Urinary Bladder - Anatomy and Physiology Home > Urinary System > Urinary System of the Lower Torso > Urinary Bladder Urinary Bladder The urinary bladder is a hollow elastic organ that functions as the body’s urine storage tank. Urine produced by the kidneys flows through the ureters to the urinary bladder, where is it stored before passing into the urethra and exiting the body. The urinary bladder plays an important role in delaying and controlling urination so that the average person only has to urinate several times each day instead of constantly leaking small amounts of urine. The urinary bladder is roughly spherical in shape, although its shape and size vary among individuals and depends greatly upon the volume of urine that it contains.... Move up/down/left/right: Click compass arrows Rotate image: Click and drag in any direction, anywhere in the frame Identify objects: Click on them in the image 2D Interactive 3D Rotate & Zoom Change Anatomical System Change View Angle Full Urinary Bladder Description [Continued from above] . . . It is located in the pelvic cavity anterior to the rectum and superior to the reproductive organs of the pelvis.

In females the urinary bladder is somewhat reduced in size and must share the limited space of the pelvic cavity with the uterus that rests superior and posterior to it. During pregnancy the uterus takes up significantly more space and severely limits the expansion of the urinary bladder. Many tiny wrinkles, known as rugae, line the inner surface of the urinary bladder and allow it to stretch as it fills with urine. A pair of ureteral openings on the inferior end of the posterior wall of the urinary bladder allow urine from the left and right ureters to enter the hollow lumen. A small funnel forms at the inferior end of the urinary bladder leading into the urethra, the tube that carries urine out of the body during urination. The urinary bladder is made of several distinct tissue layers: The innermost layer of the bladder is the mucosa layer that lines the hollow lumen. Unlike the mucosa of other hollow organs, the urinary bladder is lined with transitional epithelial tissue that is able to stretch significantly to accommodate large volumes of urine. The transitional epithelium also provides protection to the underlying tissues from acidic or alkaline urine.

Surrounding the mucosal layer is the submucosa, a layer of connective tissue with blood vessels and nervous tissue that supports and controls the surrounding tissue layers. The visceral muscles of the muscularis layer surround the submucosa and provide the urinary bladder with its ability to expand and contract. The muscularis is commonly referred to as the detrusor muscle and contracts during urination to expel urine from the body. The muscularis also forms the internal urethral sphincter, a ring of muscle that surrounds the urethral opening and holds urine in the urinary bladde. During urination, the sphincter relaxes to allow urine to flow into the urethra. The urinary bladder sits in a unique position inferior to the peritoneum, a membrane that lines most of the abdominopelvic cavity. Due to its position, the outermost layer of the superior urinary bladder is made of serous membrane continuous with the peritoneum. Serous membrane provides protection to the bladder from friction between organs in the abdominopelvic cavity. The surface of the lateral and inferior sides of the urinary bladder forms a layer of loose connective tissue known as the adventitia.

The adventitia loosely connects the urinary bladder to the surrounding tissues of the pelvis. The urinary bladder functions as a storage vessel for urine to delay the frequency of urination. It is one of the most elastic organs of the body and is able to increase its volume greatly to accommodate between 600 to 800 ml of urine at maximum capacity. Transitional epithelium, elastic fibers, and visceral muscle tissue in the walls of the urinary bladder contribute to its distensibility and elasticity, allowing it to easily stretch and return to its original size several times each day. It also helps to expel urine from the body during urination by contraction of the detrusor muscle and the relaxation of the internal urethral sphincter. Another separate muscle, the external urethral sphincter, surrounds the urethra just inferior to the bladder and helps to control and delay urination through its contraction. The external urethral sphincter is a skeletal muscle and therefore allows for the voluntary control of the urination reflex.

Prepared by Tim Taylor, Anatomy and Physiology Instructor SEER Training:Layers of the Bladder Wall Layers of the Bladder Wall Layers of the Bladder Wall The wall of the bladder wall has three principal tissue layers or coats: mucosa Transitional epithelium; lines the bladder, ureters, and urethra Epithelial layer Contains no blood or lymphatic vessels Basement membrane Lies beneath the epithelial layer; single layer of cells separating the epithelial layer from the lamina propria; a sheet of extracellular material serving as a filtration barrier and supporting structure for the mucosal layer Submucous coat (lamina propria) Areolar connective tissue; interlaced with the muscular coat. This layer contains blood vessels, nerves, and in some regions, glands. A tumor, which has spread to this layer, can metastasize to the rest of the body via the lymphatics and blood vessels.

Muscular coat (muscularis propria) Three layers: inner longitudinal, middle circular, and outer longitudinal Serous coat (serosa) A reflection of the peritoneum, which covers only the superior surface and the upper part of the lateral surfaces Adventitia In areas on bladder where there is no serosa, the connective tissue between organs merges Perivesical fat Layer of fat surrounding bladder outside of serosa/adventitia Equivalent Terms for Layers of Bladder Wall Mucosa Detrusor muscle of bladder | Article about detrusor muscle of bladder by The Free Dictionary Detrusor muscle of bladder | Article about detrusor muscle of bladder by The Free Dictionary Also found in: Dictionary , Thesaurus , Medical . muscle, the contractile tissue that effects the movement of and within the body. Muscle tissue in the higher animals is classified as striated, smooth, or cardiac, according to its structure and function. Striated, or skeletal, muscle forms the bulk of the body's muscle tissue and gives the body its general shape. It is called striated because it appears striped, in alternating bands of light and dark, when viewed under a microscope, and animals have conscious control over most of their striate muscles.

Smooth muscle, which lines most of the hollow organs of the body, is not under voluntary control, but is regulated by the autonomic nervous system. Smooth muscle fibers are spindle-shaped, not striated, and generally are arranged in dense sheets. Smooth muscle lines the blood vessels, hair follicles, urinary tract, digestive tract, and genital tract. Its speed of contraction is slower than that of striated muscle, but it can remain contracted longer. Cardiac muscle is striated like skeletal muscle but, like smooth muscle, is controlled involuntarily. It is found only in the heart, where it forms that organ's thick walls. The contractions of cardiac muscle are stimulated by a special clump of muscle tissue located on the heart (the pacemaker), although the rate of contractions is subject to regulation by the autonomic nervous system.

Muscle Contraction Skeletal muscles are attached (with some exceptions, such as the muscles of the tongue and pharynx) to the skeleton by means of tendons, usually in pairs that pull in opposite directions, e.g., the biceps biceps , any muscle having two heads, or fixed ends of attachment, notably the biceps brachii at the front of the upper arm and the biceps femoris in the thigh. Originating in the shoulder area, the heads of the biceps merge partway down the arm to form a rounded mass of tissue ..... Click the link for more information. (flexor) and triceps triceps, any muscle having three heads, or points of attachment, but especially the triceps brachii at the back of the upper arm. One head originates on the shoulder blade and two on the upper-arm bone, or humerus. ..... Click the link for more information. (extensor) that move the forearm at the elbow. The means by which all types of muscles contract is thought to be generally the same, although muscles are classified as phasic, or fast twitch, and tonic, or slow twitch, to differentiate between the various lengths of time a muscle may require to move in response to stimulation.

Striated muscle is usually considered phasic, while cardiac and smooth muscle are thought to be tonic. Perhaps because its action is most varied, striated muscle has been studied most extensively. This type of muscle is composed of numerous cylindrically shaped bundles of cells, each enclosed in a sheath called the sarcolemma. Each muscle fiber contains several hundred to several thousand tightly packed strands called myofibrils that consist of alternating filaments of the protein substances actin actin, a protein abundantly present in many cells, especially muscle cells, that significantly contributes to the cell's structure and motility. Actin can very quickly assemble into long polymer rods called microfilaments. ..... Click the link for more information. and myosin myosin , one of the two major protein constituents responsible for contraction of muscle. In muscle cells myosin is arranged in long filaments called thick filaments that lie parallel to the microfilaments of actin. ..... Click the link for more information. . Actin and myosin interact before muscle contraction, forming the contractile material actomyosin.

The energy required for muscle contraction comes from the breakdown of adenosine triphosphate adenosine triphosphate (ATP) , organic compound composed of adenine, the sugar ribose, and three phosphate groups. ATP serves as the major energy source within the cell to drive a number of biological processes such as photosynthesis, muscle contraction, and the synthesis of ..... Click the link for more information. (ATP), a substance that is present in the cells and is formed during cellular respiration respiration, process by which an organism exchanges gases with its environment. The term now refers to the overall process by which oxygen is abstracted from air and is transported to the cells for the oxidation of organic molecules while carbon dioxide (CO2 ..... Click the link for more information. . A muscle fiber is stimulated to contract by electrical impulses from the nervous system. The point of contact between nerve and muscle is the neuromuscular junction, where the chemical substance acetylcholine acetylcholine , a small organic molecule liberated at nerve endings as a neurotransmitter. It is particularly important in the stimulation of muscle tissue. The transmission of an impulse to the end of the nerve causes it to release neurotransmitter molecules onto the surface of ..... Click the link for more information.

is secreted, initiating the changes that cause the muscle to contract. During resting states, some of the fibers in the musculature are maintained in a state of partial contraction, known as muscle tone. This permits muscles to contract quickly when stimulated without having to overcome the inertia of total relaxation. Muscle The tissue in the body in which cellular contractility has become most apparent. Almost all forms of protoplasm exhibit some degree of contractility, but in muscle fibers specialization has led to the preeminence of this property. In vertebrates three major types of muscle are recognized: smooth, cardiac, and skeletal. Smooth muscle Smooth muscle, also designated visceral and sometimes involuntary, is the simplest type. These muscles consist of elongated fusiform cells which contain a central oval nucleus. The size of such fibers varies greatly, from a few micrometers up to 0.02 in. (0.5 mm) in length. These fibers contract relatively slowly and have the ability to maintain contraction for a long time. Smooth muscle forms the major contractile elements of the viscera, especially those of the respiratory and digestive tracts, and the blood vessels. Smooth muscle fibers in the skin regulate heat loss from the body.

Those in the walls of various ducts and tubes in the body act to move the contents to their destinations, as in the biliary system, ureters, and reproductive tubes. Smooth muscle is usually arranged in sheets or layers, commonly oriented in different directions. The major physiological properties of these muscles are their intrinsic ability to contract spontaneously and their dual regulation by the autonomic nerves of the sympathetic and parasympathetic systems. See Autonomic nervous system Cardiac muscle Cardiac muscle has many properties in common with smooth muscle; for example, it is innervated by the autonomic system and retains the ability to contract spontaneously. Presumably, cardiac muscle evolved as a specialized type from the general smooth muscle of the circulatory vessels. Its rhythmic contraction begins early in embryonic development and continues until death. Variations in the rate of contraction are induced by autonomic regulation and by many other local and systemic factors. The cardiac fiber, like smooth muscle, has a central nucleus, but the cell is elongated and not symmetrical. It is a syncytium, a multinuclear cell or a multicellular structure without cell walls.

Histologically, cardiac muscle has cross-striations very similar to those of skeletal muscle, and dense transverse bands, the intercalated disks, which occur at short intervals. See Heart (vertebrate) Skeletal muscle Skeletal muscle is also called striated, somatic, and voluntary muscle, depending on whether the description is based on the appearance, the location, or the innervation. The individual cells or fibers are distinct from one another and vary greatly in size from over 6 in. (15 cm) in length to less than 0.04 in. (1 mm). These fibers do not ordinarily branch, and they are surrounded by a complex membrane, the sarcolemma. Within each fiber are many nuclei; thus it is actually a syncytium formed by the fusion of many precursor cells. The transverse striations of skeletal muscle form a characteristic pattern of light and dark bands within which are narrower bands. These bands are dependent upon the arrangement of the two sets of sliding filaments and the connections between them. See Muscle proteins , Muscular system Muscle the body tissue of the skeletal and visceral musculatures.

Muscles enable animals and man to perform very important physiological functions, such as movement of the body or its individual parts, blood circulation, respiration, passing of chyme through the digestive organs, maintenance of vascular tonus, and excretion. The contractile function of all types of muscles is due to the transformation of chemical energy from certain biochemical processes into mechanical work. This transformation occurs within the muscle fibers. However, the contraction of skeletal and visceral muscles is only a particular case of a more general phenomenon—the mechanochemical activity of living structures. The most varied manifestations of this activity, for example, the contraction of the tail of a spermatozoon, the movement of cilia in infusorians, the disjunction of chromosomes during mitosis, and the injection of phage DNA into bacteria, appear to be based on the same molecular mechanism. This common mechanism involves a change in the conformation or the relative position of the fibrillar structures in contractile proteins. Classification. Morphologists distinguish two main types of muscles: striated and smooth.

Striated muscles include the entire skeletal musculature, which makes voluntary movement possible in vertebrate animals and in man; muscles of the tongue and upper third of the esophagus; heart muscle, or myocardium, which has a unique protein composition and contractile nature; and muscles of arthropods and some other invertebrates. Smooth muscles make up most of the musculature of invertebrates. In animals and man the muscular layers of the viscera and of the walls of blood vessels are also made up of smooth muscles. These muscular layers take part in the most important physiological functions. Some histologists distinguish a third type of muscle in invertebrates, muscle with double oblique striation. STRUCTURAL ELEMENTS . All types of muscles consist of muscle fibers. Striated muscle fibers in skeletal muscles form bundles joined together by layers of connective tissue. The ends of muscle fibers are intertwined with tendon fibers, and through this combination muscular tension is transmitted to the skeletal bones. Striated muscle fibers are giant, polynucleated cells ranging from 10 to 100 μ in diameter. They are frequently as long as the muscles themselves, reaching a length of 12 cm in some human muscles.

The fiber is covered with an elastic sheath, or sarcolemma. The cell is filled with a sarcoplasm that contains such organelles as mitochondria, ribosomes, the tubules and vacuoles of the sarcoplasmic reticulum and of the T-system, and various inclusion bodies. The sarcoplasm usually contains bundles of numerous threadlike structures, myofibrils, which are also cross-striated, like the muscles of which they are a part. Myofibrils are from 0.5 μ to several microns thick. Every myofibril is divided into several hundred segments, 2.5 to 3 μ in length, called sarcomeres. Every sarcomere consists, in turn, of alternating bands that differ in optical density and impart to the myofibrils and to muscle fiber as a whole a characteristic striation that can be clearly seen under a phase-contrast microscope. The darker bands are bire-fringent and are called anisotropic, or A, bands. The lighter bands do not have this capacity and are called isotropic, or I, bands. The middle of the A band is occupied by a zone of weaker birefringence, the H zone.

The I band is divided into the two equal halves of the dark Z membrane, which separates one sarcomere from another. Every sarcomere has two types of filaments, which consist of the muscle proteins thick myosin and thin actin. Smooth muscle fibers have a somewhat different structure. They are spindle-shaped, mononuclear cells lacking cross-striations. They are usually 50–250 μ long and 4–8 μ wide. Uterine smooth muscle fibers are 500 m μ long. Smooth muscle myofilaments are usually not combined into separate myofibrils but are arranged along the length of the fiber in the form of numerous single actin filaments. There is no ordered system of myosin filaments in smooth muscle cells. Tropomyosin A fibers in the smooth musculature of mollusks appear to play a major role in performing the obturator function (closing of the shell). CHEMICAL COMPOSITION . The chemical composition of muscles varies with the species, with the age of the animal, with the type and the functional condition of the muscle, and with some other factors. The principal constituents of human and animal striated muscles are presented in Table 1.

Table 1. Chemical components of striated muscle (in percent of total wet weight of muscle) Water ............... Ash ............... 1.0–1.5 On the average, water constitutes 75 percent of the wet weight of muscle. Proteins account for most of the solid mass. A distinction is made between the myofibrillar contractile proteins (myosin and actin and their complex—actomyosin—tropomyosin, α and β actins, troponin, and others) and the sarcoplasmic proteins (globulin X, myogens, respiratory pigments—such as myoglobin—nucleoproteins, and enzymes that participate in the metabolic processes in muscle). The extractive compounds that participate in metabolism and perform the contractile function of muscle are the most important of the remaining compounds in muscle fiber.

These include ATP, phosphocreatine, carnosine, and anserine; phospholipides, which play a major role in metabolism and in the formation of cellular microstructures; nitrogen-free substances, for example, glycogen and its decomposition products (glucose, lactic acid, and so forth), neutral fats, and cholesterol; and finally, salts of sodium, potassium, calcium, and magnesium. Smooth muscles differ significantly in chemical composition from striated muscles, having a lower content of the contractile protein actomyosin and of high-energy compounds and dipeptides. FUNCTIONAL CHARACTERISTICS OF STRIATED MUSCLES . Striated muscles are richly supplied with the nerves by which muscular activity is regulated from the nerve centers. The most important are the motor nerves, which conduct impulses to the muscles, causing them to become excited and to contract; the sensory nerves, along which information about the condition of the muscles reaches the nerve centers; and the adaptatotrophic fibers of the sympathetic nervous system, which act on the metabolism and slow the onset of muscle fatigue. The combination of a motor nerve and the group of muscle fibers that it innervates is called the motor unit.

Each branch of a motor nerve in a motor unit extends to a separate muscle fiber. All the muscle fibers that constitute such a unit contract almost simultaneously when they are excited. The nerve impulse causes a mediator, acetylcholine, to be released at the end of the motor nerve. Acetylcholine then reacts with the choline receptor at the postsynaptic membrane. This increases the permeability of the membrane to sodium and potassium ions, causing the membrane to become depolarized: a postsynaptic potential appears. A wave of electronegativity then arises in adjacent portions of the skeletal muscle fiber membrane and is propagated along the muscle fiber, usually at the rate of several meters per second. The elastic properties of muscles change as a result of excitation. If the points of attachment of the muscle are not rigidly fixed, the muscle contracts, performing mechanical work. If the points of attachment of the muscle are fixed, tension develops in the muscle. A latent period ensues between the origin of excitation and the appearance of a wave of contraction or tension. Muscular contraction is accompanied by a release of heat that continues for some time even after the muscle relaxes.

The muscles of mammals and man can consist of slow (red) muscle fibers, containing the respiratory pigment myoglobin, and rapid (white) fibers, containing no myoglobin. Rapid and slow fibers differ from one another both in the rate of conduction of the contractile wave and in the wave’s duration. In mammals the duration of the wave of contraction in slow fibers is five times as great as in rapid fibers, but the rate of conduction is only half as great as in rapid fibers. Almost all skeletal muscles are of a mixed type, that is, they contain both rapid and slow fibers. Either single (or phasic) contraction of the muscle fibers or tetanic (or prolonged) contraction can arise, depending on the nature of the stimulus. Tetany occurs when a series of stimulations reaches a muscle at such a rate that each successive stimulation still leaves the muscle in a state of contraction, causing a superimposition of the contractile waves. N. E.

Vbedenskii discovered that increasing the rate of stimulation intensifies the tetany, but only to a certain limit, which he called the “optimum.” Further increases in the rate of stimulation diminishes tetanic contraction to the “pessimum.” The onset of tetany is important in the contraction of slow muscle fibers. In muscles with a predominance of rapid fibers, maximum contraction usually results from the superimposition of contractions from all those motor units that are simultaneously active. To accomplish this, the nerve impulses usually reach these motor units asynchronously. Striated muscles also contain a third type of fiber, purely tonic fibers, which are especially well represented in the muscles of amphibians and reptiles. Tonic fibers help to maintain a continuous muscle tonus. Tonic contractions are slowly developing, coordinated contractions, capable of persisting a long time without a significant energy loss. Muscles in tonic contraction manifest a continuous resistance to any external forces that are applied toward dilating a muscular organ. Tonic fibers react to a nerve impulse with a contractile wave only at the site of stimulation. Nevertheless, owing to the large number of motor endplates—stimulation sites—a tonic fiber can still become excited and completely contract.

Such fibers contract so slowly that even at very low frequencies of stimulation, individual waves of contraction superimpose and merge to produce a single, prolonged contraction. The prolonged resistance of tonic fibers and slow phasic fibers to a tensile force is ensured not only by the contractile function of the muscle proteins but also by increased viscosity of the proteins. The contractile ability of a muscle is expressed in terms of the muscle’s absolute strength, the ratio of a muscle’s mass to the area of its cross-section taken at the plane perpendicular to the fibers. Absolute strength is expressed in kilograms per centimeter squared (kg/cm2). For example, the absolute strength of the human biceps is 11.4 kg/cm2, and that of the gastrocnemius, 5.9 kg/cm2. Systematic exercise of muscles increases their mass, strength, and efficiency. However, excessive work results in fatigue, that is, loss of muscular efficiency. Inactivity causes muscles to atrophy. FUNCTIONAL CHARACTERISTICS OF SMOOTH MUSCLES . Smooth muscles of the internal organs differ significantly from skeletal muscles in the manner of innervation, excitation, and contraction. The waves of excitation and contraction proceed very slowly in smooth muscles.

In such muscles the development of a continuous muscle tonus is related, as in tonic skeletal fibers, to the slow rate of propagation of the contractile waves, which merge with one another even after infrequent rhythmic stimulation. The phenomenon of automatism (activity not caused by the entry of nerve impulses from the central nervous system into the muscle) is also characteristic of smooth muscles. Both the nerve cells that innervate smooth muscle and the smooth-muscle cells themselves have been found to be capable of spontaneous—independent of central nervous system stimulation—rhythmic excitation and contraction. Smooth muscles in vertebrates are unique not only in their innervation and histological structure but also in their chemical composition. They have a lower content of the contractile protein actomyosin; fewer high-energy compounds, particularly ATP; a low ATPase activity in the myosin fraction; and a water-soluble variety of actomyosin, called tonoactomyosin. Of great importance to the organism is the ability of smooth muscles to change length without increasing the tension exerted. Such a situation arises, for example, during the filling of hollow organs, such as the urinary bladder and stomach. I. I. I VANOV Skeletal muscles in man.

Skeletal muscles in man, which differ from one another in shape, size, and position, constitute about 40 percent of the body mass. Upon contracting, the muscle can shorten to 60 percent of its length. The longer the muscle (the longest muscle, the sartorius, is 50 cm long), the greater its range of movements. Contraction of a dome-shaped muscle, for example, the diaphragm, results in flattening, while contraction of a ring-shaped muscle, for example, a sphincter, results in constriction or closure of the opening that the muscle surrounds. A radial muscle, on the other hand, widens the opening when it contracts. The contraction of muscles that are located between bony prominences and the skin changes the shape of the skin surface. All skeletal, or somatic, muscles can be classified according to their location into muscles of the head (these include the facial muscles and the masseter muscles controlling the lower jaw) and muscles of the neck, the trunk, and the extremities. Since truncal muscles cover the chest and form the walls to the abdominal cavity, they are divided into thoracic, abdominal, and spinal muscles.

Muscles of the extremities are classified according to which segment of the skeleton they are associated with. In the upper extremities there are the muscles of the shoulder girdle, of the shoulder, of the forearm, and of the hand; in the lower extremities there are the muscles of the pelvic girdle, of the hip, of the shin, and of the foot. In man there are about 500 muscles attached to the skeleton. Some of them are large, for example, the quadriceps femoris, while others are small, for example, the short muscles of the back. Work that involves several muscles is performed synergistically, although some functional muscle groups work antagonistically when carrying out certain movements. For example, the biceps and the brachialis muscles in the front of the forearm flex the forearm at the elbow joint, while the triceps brachii, located in back, serves to extend the forearm. Both simple and complex movements occur in the spheroid articulations. For example, the hip is flexed at the hip joint by the iliopsoas and extended by the gluteus maximus.

The hip is abducted by the gluteus minimus and the gluteus medius and adducted by five muscles of the medial group of the hip. The hip joint is also surrounded by muscles that rotate the hip laterally and medially. The most powerful muscles are those of the trunk. They include the muscles of the back, which keep the trunk erect, and the abdominal muscles, which constitute an unusual formation in man, the prelum abdominale. In the course of evolution, the muscles of the lower extremities in man have become stronger on account of the vertical position of the body. They support the body as well as participate in locomotion. The muscles of the upper extremities, conversely, have become more dextrous in order to guarantee the execution of rapid and precise movements. On the basis of physical location and functional activity, modern science also classifies muscles according to the following group: the muscle group that controls movement in the trunk, head, and neck; the muscle group that controls movement of the shoulder girdle and the free upper extremity; and the muscles of the lower extremity. Smaller divisions are distinguished within these groups. V. V. K UPRHANOV Pathology of muscles.

The impairment of contractility and the development of a prolonged muscle tonus are observed in the following disturbances, to name a few: in hypertension, myocardial infarction, and myodystrophy; in atonia of the uterus, intestine, and urinary bladder; in some forms of paralysis, for example, after recovery from poliomyelitis. Pathological changes in the functioning of muscular organs may result from disturbances in nervous or humoral regulation, from injuries to any part of the muscles (for example, in myocardial infarction), or from changes at the cellular and subcellular levels. Subcellular and cellular disturbances can involve a change in the contractile protein substrate or a change in metabolism. Metabolic changes usually occur within the enzymatic system that is concerned with the regeneration of high-energy compounds, especially ATP. Subcellular and cellular changes may be caused by the insufficient production of muscle proteins that follows the impairment of messenger RNA synthesis. Such impairment results in congenital defects in the structure of the chromosomal DNA. This last group of diseases is therefore considered hereditary.

The sarcoplasmic proteins in skeletal and smooth muscles are of interest not only because they participate in the development of the viscous aftereffect but also because many of them are enzymatically active and take part in the cell’s metabolism. When muscular organs are injured, as in myocardial infarction, or when the permeability of the surface membranes of muscle fibers is impaired, enzymes such as creatine kinase, lactate dehydrogenase, aldolase, and transaminase may escape into the blood. Thus, in certain diseases, such as myocardial infarctions and myopathies, it is of considerable clinical interest to determine the activity of these enzymes in the plasma. REFERENCES Engel’gardt, V. A. “Fermentativnye i mekhanicheskie svoistva belkov myshts.” Uspekhi sovremennoi biologii, 1941, vol. 14, issue 2. Szent-Gyorgyi, A. O myshechnoi deiatel’nosti. Moscow, 1947. (Translated from English.) Ivanov, I. I., and V. A. Iur’ev.

Biokhimiia i patobiokhimiia myshts. Leningrad, 1961. Poglazov, B. F. Struktura i funktsii sokratitel’nykh belkov. Moscow, 1965. Hayashi, T. “Kak kletki dvizhutsia.” In Zhivaia kletka, 2nd ed. Moscow, 1966. (Translated from English.) Huxley, G. “Mekhanizm myshechnogo sokrashcheniia.” In the collection Molekuly i kletki, fasc. 2. Moscow, 1967. (Translated from English.) Smith, D. “Letatel’nye myshtsy nasekomykh.” Ibid. Bendoll, J. Myshtsy, molekuly i dvizhenie. Moscow, 1970. (Translated from English.) Arronet, N. I. Myshechnye i kletochnye sokratitel’nye (dvigatel’nye) modeli. Leningrad, 1971.

Loewy, A., and P. Siekewitz. Struktura i funktsii kletki. Moscow, 1971. (Translated from English.) Ivanov, I. I. “Nekotorye aktual’nye problemy evoliutsionnoi biokhimii myshts.” Zhurnal evoliutsionnoi biokhimii i fiziologii, 1972, vol. 8, no. 3. Gibbons, I. R. “The Biochemistry of Motility.” Annual Review of Biochemistry, 1968, vol. 37, p. 521. I. I. I Urinary Bladder Urinary Bladder Human Anatomy » Body Systems » Urinary System » Urinary Bladder Urinary bladder is the sac-like hollow muscular and distensible organ that collects urine formed in the kidney and temporarily stores it before it can be excreted from the body. Urinary bladder is situated immediately behind the pubic bones within the pelvis. It has strong muscular walls with three openings: two for ureters and one for urethra.

Location: Urinary bladder of an adult person has a maximum capacity of about 500ml. Its shape and relations vary according to the amount of urine that it contains. Empty bladder lies entirely within the pelvis, however, as it fills with urine, superior wall rises up into the hypogastric region. Shape: Empty bladder is pyramidal in shape. It has an apex, a base, a superior surface and two inferolateral surfaces. The apex points anteriorly and lies behind the upper margin of the symphysis pubis. It is connected to the umbilicus by the median umbilical ligament, which represents the remains of the urachus. The base of the bladder is triangular and faces posteriorly. The superolateral angles of the bladder are joined by the ureters and the inferior angle is joined by the urethra. The vasa deferentia lie side by side on the posterior surface, separating the seminal vesicles from one another. Peritoneal covering: The upper part of the posterior surface of the bladder is covered by peritoneum. This part forms the anterior wall of the rectovesical pouch in males. The lower part of the posterior surface is devoid of peritoneum.

The superior surface of the bladder is covered completely by peritoneum. Along the lateral margins, the peritoneum passes onto the lateral walls of the pelvis. This means that anterior and lateral parts of the bladder are devoid of peritoneum. As the bladder fills with urine, the peritoneum peels off from the anterior wall of pelvis so that the bladder comes in direct contact with the anterior abdominal wall. Neck of bladder: Neck of the urinary bladder is its inferior part that rests on the prostate gland. Here the smooth muscle fibers of the bladder are continuous with those of the prostate. The neck is also supported by the puboprostatic ligaments (in males) or pubovesical ligaments (in females). These ligaments are thickenings of pelvic fascia. When the bladder gets filled with urine, the support of the neck makes it stationary and only the superior surface of the bladder rises into the abdominal cavity. Trigone: Trigone is the triangular area of mucous membrane covering the internal surface of the base of the bladder between the two ureteral orifices superiorly and the urethral orifice inferiorly.

Unlike the rest of the bladder, the mucous membrane of trigone is always devoid of folds, even when the bladder is empty. The reason is that in this region the mucous membrane is firmly adherent to the underlying muscular coat. Embryologically, the trigone has a different origin than the rest of the bladder. It arises from mesonephric ducts (mesodermal in origin) while the rest of the bladder is endodermal in origin. Detrusor muscle: The layer of bladder wall made of smooth muscle is collectively called detrusor muscle. It is composed of three layers of smooth muscle fibers: spiral, longitudinal and circular. It is the detrusor muscle whose contraction causes expulsion of urine from the bladder, under the action of parasympathetic nervous system. Blood supply: Arterial supply is through superior and inferior vesical arteries, which are both branches of internal iliac artery. Venous drainage occurs by the way of vesical venous plexus, which drains into the internal iliac nodes. Lymph drainage: Lymph from the bladder drains into internal and external iliac nodes. Nerve supply: Nerve supply to bladder comes from the inferior hypogastric plexus.

Sympathetic fibers originate in 1st and 2nd lumbar ganglia Parasympathetic fibers arise as pelvic splanchnic nerves Afferent sensory fibers reach the central nervous system via the pelvic splanchnic nerves Generally, the sympathetic fibers inhibit contraction of the bladder wall and close the sphincter. Thus they inhibit micturition. On the other hand, parasympathetic fibers contract the bladder wall and relax the sphincters, thus they promote micturition. Share this page: Anatomy of the Bladder and Urethra: Section about the Renal System (also known as the Urinary System). No significant benefit from routine use of antibiotics for malnourished children - 8 Feb 2016 Anatomy of the Bladder and Urethra Remember (from the page about the functions of the urinary system ) that the purpose of the urinary bladder is to store urine prior to the elimination of the urine from the body. The bladder expels urine into a tube called the urethra that leads to the exterior of the body. Elimination of urine occurs by a process called micturition - which is also known as urination.

This page describes the structures of the human urinary bladder* then links on to details of the male and female urethras - illustrated and described separately. General location in the body The bladder is located on the floor of the pelvic cavity. (Other organs, glands and tissues located in the pelvic cavity include the rectum, gender-specific reproductive organs, parts of the small intestine, blood vessels, lymphatic vessels, and nerves.) The bladder is located anterior to (i.e. in front of) the rectum in males. In females it is also in front of the uterus and upper vagina so its location is described simply as "anterior to the uterus and upper vagina". The Structure of the Bladder (structure common to male and female) The urinary bladder is a musculomembranous sac whose shape is affected by factors including the person's age and sex - as well as the volume of urine it contains at the time. Outer surfaces of the Bladder The upper and side surfaces (i.e. the "superior" or "abdominal" surfaces, and the "lateral" surfaces) of the bladder are covered by peritoneum. This is the serous membrane of the abdominal cavity.

Sometimes referred to as "serosa" this transparent membrane consists of mesthelium and elastic fibrous connective tissue. Note that, strictly, it is "visceral peritoneum" that covers the bladder and other abdominal organs, while "parietal peritoneum" lines the abdomen walls. Ureters The ureters deliver urine to the bladder from the kidneys (one ureter from each kidney - see components of human urinary system ). The ureters are retroperitoneal, which means that they are located in the retroperitoneal space (i.e. the area between the back/"posterior" surface of the parietal peritoneum and the front/"anterior" of the lumbar vertebrae). This makes sense when it is remembered that the kidneys are among the organs and glands located in the retroperitoneal space - and the ureters connect the kidneys to the bladder. In adults the ureters are approx 12 inches (30 cm) long and have a muscular coat (not shown in diagram) that tightens and relaxes to move urine away from the kidney.

This muscular action is controlled by the autonomic nervous system (ANS) and operates in a similar way to that of peristalsis in the digestive system. The ureters pass through the posterior surface of the bladder at the Ureter Orifices (as shown for male and female bladders). Urine drains through the ureters directly into the bladder as there are no sphincter muscles or valves at the ureter orifices. Structure of Bladder (Detail) The bladder itself ("musculomembranous sac") consists of 4 layers: Serous SEER Training:Urinary Bladder Urinary Bladder Updates Urinary Bladder The urinary bladder is a temporary storage reservoir for urine. It is located in the pelvic cavity, posterior to the symphysis pubis, and below the parietal peritoneum . The size and shape of the urinary bladder varies with the amount of urine it contains and with the pressure it receives from surrounding organs. The inner lining of the urinary bladder is a mucous membrane of transitional epithelium that is continuous with that in the ureters. When the bladder is empty, the mucosa has numerous folds called rugae.

The rugae and transitional epithelium allow the bladder to expand as it fills. The second layer in the walls is the submucosa, which supports the mucous membrane. It is composed of connective tissue with elastic fibers. The next layer is the muscularis, which is composed of smooth muscle. The smooth muscle fibers are interwoven in all directions and, collectively, these are called the detrusor muscle. Contraction of this muscle expels urine from the bladder. On the superior surface, the outer layer of the bladder wall is parietal peritoneum. In all other regions, the outer layer is fibrous connective tissue. There is a triangular area, called the trigone, formed by three openings in the floor of the urinary bladder. Two of the openings are from the ureters and form the base of the trigone. Small flaps of mucosa cover these openings and act as valves that allow urine to enter the bladder but prevent it from backing up from the bladder into the ureters. The third opening, at the apex of the trigone, is the opening into the urethra. A band of the detrusor muscle encircles this opening to form the internal urethral sphincter.

Bladder Anatomy: Overview, Gross Anatomy, Microscopic Anatomy Microscopic Anatomy Overview Overview The bladder is an extraperitoneal muscular urine reservoir that lies behind the pubic symphysis in the pelvis. A normal bladder functions through a complex coordination of musculoskeletal, neurologic, and psychological functions that allow filling and emptying of the bladder contents. The prime effector of continence is the synergic relaxation of detrusor muscles and contraction of the bladder neck and pelvic floor muscles. This occurs during bladder filling and urine storage. See the image below. Gross anatomy of the bladder. View Media Gallery The normal adult bladder accommodates 300-600 mL of urine. A central nervous system response is usually triggered when the volume reaches 400 mL and is perceived as the sensation of bladder fullness and the need to void. However, urination can be prevented by cortical suppression of the peripheral nervous system or by voluntary contraction of the external urethral sphincter. [ 1 ] Next: Gross Anatomy The adult bladder is located in the anterior pelvis and is enveloped by extraperitoneal fat and connective tissue.

It is separated from the pubic symphysis by an anterior prevesical space known as the space of Retzius or retropubic space. The dome of the bladder is covered by peritoneum, and the bladder neck is fixed to neighboring structures by reflections of the pelvic fascia and by true ligaments of the pelvis. The body of the bladder receives inferior support from the pelvic diaphragm in females or prostate in males and lateral support from the obturator internus and levator ani muscles. At its apex, the medial umbilical ligament, or the urachal remnant, courses along the anterior abdominal wall to the umbilicus. [ 2 , 3 ] See the image below. Gross anatomy of the bladder. View Media Gallery Bladder neck The bladder neck serves as the internal sphincter in women. At the bladder neck, the muscular bladder wall is more organized and 3 relatively distinct layers become apparent. The inner longitudinal muscle layer fuses with the inner longitudinal layer of the urethra. The middle circumferential muscle layer is most prominent in the proximity of the bladder neck, and it fuses with the deep trigonal muscle layer.

The outer longitudinal muscle layer contributes some anterior fibers to what become the pubovesical muscles, which terminate on the posterior surface of the pubic bone. Posteriorly, the outer longitudinal fibers interdigitate with deep trigonal fibers and the detrusor muscle. See the image below. The female bladder, internal sphincter, external sphincter, and urethra. The internal sphincter is more of a functional concept than a distinct anatomic entity. View Media Gallery It is thought that the differing groups of muscle fibers aid in bladder neck opening during micturition and bladder neck closure during bladder filling and urine storage phases. In addition to these muscle layers, the pubourethral ligament serves to support the bladder neck and urethra via attaching these structures to the dorsal aspect of the pubis. In males, the bladder neck is contiguous with the prostate and both serve together as the internal urethral sphincter. The prostate is attached to the pubis by puboprostatic ligaments.

Trigone The trigone is a triangular portion of the bladder floor bordered (ventrally) by the internal urethral opening or bladder neck and (dorsolaterally) by the orifices of the right ureter and left ureter. The ureters , which transport urine from the kidneys to the bladder and insert into the trigone, approach the bladder as they course inferiorly from their posterolateral locations. The superior or dorsal border of the trigone is a raised area termed the interureteric ridge, which courses from one ureteral meatus to the other. The intravesical ureteral orifices are roughly 2-3 cm apart. The intramural ureters are each about 1.5 cm in length. Vascular supply The arterial blood supply of the bladder arrives primarily via the internal iliac (hypogastric) arteries. These branch into the umbilical artery, which supplies several superior vesicle branches, and inferior vesical arteries, which come as direct internal iliac branches in males or from the vaginal arteries in females. The arterial supply of the bladder is also derived in part from the obturator artery and inferior gluteal artery.

In females, this is via the uterine artery and vaginal artery. The venous return of the bladder is a rich network of vessels that generally parallels the arteries in both anatomic course and name. The vast majority of venous return from the bladder drains into the internal iliac vein. Lymphatic drainage The lymphatic drainage of the bladder is into the obturator, external iliac, internal iliac (hypogastric), and common iliac lymph nodes. As with any region of the body, prior surgery may alter the lymphatic outflow of the region. The internal iliac lymph nodes are usually the primary site of lymphadenopathy related to bladder pathology. Bladder in relation to nearby structures In males, the seminal vesicles, ductus deferens, ureters, and rectum border the inferoposterior aspect of the bladder and prostate. Anterior to the bladder is the space of Retzius or retropubic space, which is composed of fibroadipose tissue and the prevesical fascia. The dome and posterior surface of the bladder are covered by parietal peritoneum, which reflects superiorly to the seminal vesicles and is continuous with the anterior rectal peritoneum.

In females, the posterior peritoneal reflection is continuous with the uterus and vagina and is referred to as the anterior cul-de-sac or vesicouterine pouch. The inferoposterior aspect of the bladder thus rests on the anterior vaginal wall, through which the urethra courses. As a result of positioning adjacent to the reproductive organs and behind the bony pubis, the bladder neck and urethra are at risk for both direct and hypoxic injury during childbirth. [ 4 , 5 ] See the image below. Gross anatomy of the female pelvis. Urinary Bladder Development - Embryology Urinary Bladder Development Expand to Translate Google Translate - select your language from the list shown below (this will open a new external page) Introduction Interior of the urinary bladder The paired adult kidneys filter blood, reabsorb water, have endocrine functions and excrete waste. The waste in the form of urine for excretion, collects initially in the renal pelvis and flows through the ureters to the urinary bladder. The wall of the urinary bladder is composed of layers of smooth muscle and in the male has close anatomical relationship with the prostate gland. (More?

Prostate Development ) Abnormalities in renal development can lead to ureter obstruction and interfere with flow of urine to the bladder during the fetal period. The common name for the urinary bladder is simply the "bladder". Some Recent Findings Mouse cloacal septation Morphology of the fetal bladder during the second trimester: Comparing genders [1] "Forty bladders, which were obtained from 40 human fetuses (20 males and 20 females) ranging in age from 13 to 23 weeks post-conception (WPC), were studied. The fetuses weighed between 60 and 490 g, and had crown-rump lengths between 9.5 and 20.4 cm. No elastic system fibers were observed in any bladders.

...The histological analysis of the smooth muscle, collagen, nerves and connective tissue of the developing bladders revealed that there are no gender differences during weeks 13-23 of gestation." Spatio-temporal distribution of Smads and role of Smads/TGF-β/BMP-4 in the regulation of mouse bladder organogenesis [2] "Although Shh, TGF-β and BMP-4 regulate radial patterning of the bladder mesenchyme and smooth muscle differentiation, it is not known what transcription factors, local environmental cues or signaling cascades mediate bladder smooth muscle differentiation. ...Based on the Smad expression patterns, we suggest that individual or combinations of Smads may be necessary during mouse bladder organogenesis and may be critical mediators for bladder smooth muscle differentiation." TGF-beta Endodermal origin of bladder trigone inferred from mesenchymal-epithelial interaction [3] "In the classic view of bladder development the trigone originates from the mesoderm derived wolffian ducts while the remainder of the bladder originates from the endoderm derived urogenital sinus. Recent molecular developmental studies have questioned the veracity of this received wisdom, suggesting an endodermal origin for the trigone.

To shed further light on this issue we observed mesenchymal-epithelial interactions between trigone epithelium and fetal urogenital sinus mesenchyma to infer the trigonal germ layer of origin." More recent papers This table shows an automated computer PubMed search using the listed sub-heading term. Therefore the list of references do not reflect any editorial selection of material based on content or relevance. References appear in this list based upon the date of the actual page viewing. References listed on the rest of the content page and the associated discussion page (listed under the publication year sub-headings) do include some editorial selection based upon both relevance and availability. Search term: Bladder Embryology Michael Stark, Ospan Mynbaev, Yuri Vassilevski, Patrick Rozenberg Could Revision of the Embryology Influence Our Cesarean Delivery Technique: Towards an Optimized Cesarean Delivery for Universal Use.

AJP Rep: 2016, 6(3);e352-e354 PubMed 28078171 Marilena Manthou, Diana Saad Yousif Abdulla, Stoyan Pavlov Pavlov, Ramona Jansen, Habib Bendella, Klaus Nohroudi, Gregor Stein, Carolin Mmeyer, Ozlem Ozsoy, Umut Ozsoy, Yasemin Behram Kandemir, Levent Sarikcioglu, Oliver Semler, Eckhard Schoenau, Sarah Dunlop, Doychin Nikolov Angelov Whole body vibration (WBV) following spinal cord injury (SCI) in rats: Timing of intervention. Restor. Neurol. Neurosci.: 2017; PubMed 28059803 Magdalena Kowalska, Mateusz Hermyt, Weronika Rupik Three-dimensional reconstruction of the embryonic pancreas in the grass snake Natrix natrix L. (Lepidosauria, Serpentes) based on histological studies.

Zoology (Jena): 2016; PubMed 27889104 Maria-Giuliana Vannucchi, Maria-Simonetta Faussone-Pellegrini The Telocyte Subtypes. Adv. Exp. Med. Biol.: 2016, 913;115-126 PubMed 27796883 M İrfan Dönmez, Kubilay İnci, Naciye Dilara Zeybek, H Serkan Doğan, Ali Ergen The Early Histological Effects of Intravesical Instillation of Platelet-Rich Plasma in Cystitis Models. Int Neurourol J: 2016, 20(3);188-196 PubMed 27706013 Textbook References The Developing Human: Clinically Oriented Embryology (8th Edition) by Keith L. Moore and T.V.N Persaud - Moore & Persaud Chapter 13 p303-346 Larsen’s Human Embryology by GC. Schoenwolf, SB. Bleyl, PR.

Brauer and PH. Francis-West - Chapter 10 p261-306 Movies Dorsal view of developing bladder ‎‎Trigone Ultrasound measurement of the bladder size can be used as a diagnostic tool for developmental abnormalities. Bladder Structure Urinary bladder histology Can be described anatomically by its 4 layers from outside inward: Serous - the superior or abdominal surfaces and the lateral" surfaces of the bladder are covered by visceral peritoneum, the serous membrane (serosa) of the abdominal cavity, consisting of mesthelium and elastic fibrous connective tissue. Muscular - the detrusor muscle is the muscle of the urinary bladder wall. Submucosa - connects the muscular layer with the mucous layer. Mucosa - (mucus layer) a transitional epithelium layer formed into folds (rugae). Urinary bladder wall drawing The adult detrusor muscle consists of three layers of smooth (involuntary) muscle fibres.

external layer - fibres arranged longitudinally middle layer - fibres arranged circularly internal layer - fibres arranged longitudinally Ureter Development The adult ureter is a thick-walled muscular tube, 25 - 30 cm in length, running from the kidney to the urinary bladder. Anatomically can be described in two parts the abdominal part (pars abdominalis) and pelvic part (pars pelvina). The ureter is composed of three layers: outer fibrous layer (tunica adventitia), muscular layer (tunica muscularis) and mucous layer (tunica mucosa). The muscular layer can also be subdivided into 3 fibre layers: an external longitudinal, a middle circular, and an internal longitudinal. Trigone Development Page | Play Week 8 The Carnegie stage 22 human male embryo is 27mm (CRL) in size and approximately equal to day 54 - 56 of development. These images have been selected to show some key features of late embryo development. Horseshoe kidney fusion of the lower poles of the kidney. During migration from the sacral region the two metanephric blastemas can come into contact, mainly at the lower pole.

The ureters pass in front of the zone of fusion of the kidneys. The kidneys and ureters usually function adequately but there is an increased incidence of upper urinary tract obstruction or infection. Some horseshoe variations have been described as having associated ureter abnormalities including duplications. Urorectal Septum Malformation thought to be a deficiency in caudal mesoderm which in turn leads to the malformation of the urorectal septum and other structures in the pelvic region. Recent research has also identified the potential presence of a persistent urachus prior to septation of the cloaca (common urogenital sinus). Bladder absent or small bladder - associated with renal agenesis. Bladder Exstrophy Bladder_Exstrophy developmental abnormality associated with bladder development. origins appear to occur not just by abnormal bladder development, but by a congenital malformation of the ventral wall of abdomen (between umbilicus and pubic symphysis). There may also be other anomolies associated with failure of closure of abdominal wall and bladder (epispadias, pubic bone anomolies).

Ureter and Urethra Urethra- Urethral Obstruction and Hypospadias Prune Belly Syndrome Keith, A. (1902) Human Embryology and Morphology . London: Edward Arnold. The Uro-genital System Fig. 99. A section of the male bladder and urethra at birth References ↑ L A Favorito, H M Pazos, S F Costa, W S Costa, F J Sampaio Morphology of the fetal bladder during the second trimester: Comparing genders. J Pediatr Urol: 2014; PubMed 25434295 ↑ 2.0 2.1 Syed S Islam, Reza Bayat Mokhtari, Sushil Kumar, Joe Maalouf, Sara Arab, Herman Yeger, Walid A Farhat Spatio-temporal distribution of Smads and role of Smads/TGF-β/BMP-4 in the regulation of mouse bladder organogenesis.

PLoS ONE: 2013, 8(4);e61340 PubMed 23620745 ↑ Stacy T Tanaka, Kenichiro Ishii, Romano T Demarco, John C Pope, John W Brock, Simon W Hayward Endodermal origin of bladder trigone inferred from mesenchymal-epithelial interaction. J. Urol.: 2010, 183(1);386-91 PubMed 19914648 PMC2794964 | J Urol. ↑ Sahar N Saleem Fetal MRI: An approach to practice: A review. J Advanc Res: 2014, 5(5);507-23 PubMed 25685519 | J Adv Res. ↑ Vishal Gajbhiye, Sasanka Nath, Priya Ghosh, Argha Chatterjee, Dipanjan Haldar, Sukanta K Das Complete duplication of the urinary bladder: An extremely rare congenital anomaly.

Urol Ann: 2013, 7(1);91-3 PubMed 25657554 | Urol Ann. Reviews Ellen Shapiro Clinical implications of genitourinary embryology. Curr Opin Urol: 2009, 19(4);427-33 PubMed 19461520 Andrea Brenner-Anantharam, Cristina Cebrian, Richard Guillaume, Romulo Hurtado, Tung-Tien Sun, Doris Herzlinger Tailbud-derived mesenchyme promotes urinary tract segmentation via BMP4 signaling. Development: 2007, 134(10);1967-75 PubMed 17442697 Frank Costantini Renal branching morphogenesis: concepts, questions, and recent advances.

Differentiation: 2006, 74(7);402-21 PubMed 16916378 Search Bookshelf bladder development | trigone development ureter development Articles Renata Viana, Ekatherina Batourina, Hongying Huang, Gregory R Dressler, Akio Kobayashi, Richard R Behringer, Ellen Shapiro, Terry Hensle, Sarah Lambert, Cathy Mendelsohn The development of the bladder trigone, the center of the anti-reflux mechanism. Development: 2007, 134(20);3763-9 PubMed 17881488 Search PubMed Search Pubmed: urinary bladder development | bladder development Terms bladder exstrophy - A congenital malformation with bladder open to ventral wall of abdomen (between umbilicus and pubic symphysis) and may have other anomolies associated with failure of closure of abdominal wall and bladder (epispadias, pubic bone anomolies). hydronephrosis - (congenital hydronephrosis, Greek, hydro = water) A kidney abnormality due to partial or complete obstruction at the pelvi-ureteric junction.

This leads to a grossly dilated renal pelvis causing extensive renal damage before birth. mesonephric duct - (= Wollfian duct) An early developing urogenital duct running the length of the embryo that will differentiate and form the male reproductive duct system. In females this duct degenerates (some remnants may remain associated in broad ligament). proteinuria - The abnormal presence of protein in the urine and an indicator of diesease including diabetic kidney disease (DKD, diabetic nephropathy). renal - (Latin, renes = kidney) Term used in relation to the kidney and associated structures (renal pelvis, renal artery) ureter - The two ureters are hollow tubes that link and carries urine from kidney to the bladder. The tubes have a muscular wall lined with transitional epithelium. urethra - The single muscular tube that links and carries urine from the bladder to the exterior. In humans, the urethral length differs between the sexes (male longer, female shorter). urinary - Term used to describe all components of the kidney system including the bladder, ureters and urethra.

urine - Term used to describe the liquid waste produced by the kidney, stored in the bladder and excreted from teh body through the urethra. urorectal septum - (URS) The structure which develops to separate the cloaca (common urogenital sinus) into an anterior urinary part and a posterior rectal part. Wolffian duct - (= mesonephric duct, preferred terminology), runs from the mesonephros to cloaca, differentiates to form the male vas deferens and in the female regresses. Named after Caspar Friedrich Wolff (1733-1794), a German scientist and early embryology researcher and is said to have established the doctrine of germ layers. (More? Caspar Friedrich Wolff )

Question: A detrusor is a muscle which forms a layer on the wall of which part of the human body?
Answer: Bladder