Connective Tissues: Loose, Fibrous, and Cartilage About Watch and Favorite Watch Watching this resources will notify you when proposed changes or new versions are created so you can keep track of improvements that have been made. Favorite Favoriting this resource allows you to save it in the “My Resources” tab of your account. There, you can easily access this resource later when you’re ready to customize it or assign it to your students. Connective Tissues: Loose, Fibrous, and Cartilage Connective tissue is found throughout the body, providing support and shock absorption for tissues and bones. Learning Objective Distinguish between the different types of connective tissue Key Points Fibroblasts are cells that generate any connective tissue that the body needs, as they can move throughout the body and can undergo mitosis to create new tissues. Protein fibers run throughout connective tissue, providing stability and support; they can be either collagen , elastic, or reticular fibers. Loose connective tissue is not particularly tough, but surrounds blood vessels and provides support to internal organs. Fibrous connective tissue, which is composed of parallel bundles of collagen fibers, is found in the dermis, tendons, and ligaments.

Hyaline cartilage forms the skeleton of the embryo before it is transformed into bone; it is found in the adult body at the tip of the nose and around the ends of the long bones, where it prevents friction at the joints. Fibrocartilage is the strongest of the connective tissues; it is found in regions of the body that experience large amounts of stress and require a high degree of shock absorption, such as between the vertebrae. Terms Full Text Connective Tissues Connective tissues are composed of a matrix consisting of living cells and a non-living substance, called the ground substance. The ground substance is composed of an organic substance (usually a protein) and an inorganic substance (usually a mineral or water). The principal cell of connective tissues is the fibroblast, an immature connective tissue cell that has not yet differentiated. This cell makes the fibers found in nearly all of the connective tissues. Fibroblasts are motile , able to carry out mitosis, and can synthesize whichever connective tissue is needed. Macrophages , lymphocytes , and, occasionally, leukocytes can be found in some of the tissues, while others may have specialized cells.

The matrix in connective tissues gives the tissue its density . When a connective tissue has a high concentration of cells or fibers, it has a proportionally-less-dense matrix. The organic portion, or protein fibers, found in connective tissues are either collagen, elastic, or reticular fibers. Collagen fibers provide strength to the tissue, preventing it from being torn or separated from the surrounding tissues. Elastic fibers are made of the protein elastin; this fiber can stretch to one and one half of its length, returning to its original size and shape. Elastic fibers provide flexibility to the tissues. Reticular fibers, the third type of protein fiber found in connective tissues, consist of thin strands of collagen that form a network of fibers to support the tissue and other organs to which it is connected. Loose (Areolar) Connective Tissue Loose connective tissue, also called areolar connective tissue, has a sampling of all of the components of a connective tissue. Loose connective tissue has some fibroblasts, although macrophages are present as well. Collagen fibers are relatively wide and stain a light pink, while elastic fibers are thin and stain dark blue to black .

The space between the formed elements of the tissue is filled with the matrix. The material in the connective tissue gives it a loose consistency similar to a cotton ball that has been pulled apart. Loose connective tissue is found around every blood vessel, helping to keep the vessel in place. The tissue is also found around and between most body organs. In summary, areolar tissue is tough, yet flexible, and comprises membranes. Types of Connective Tissue About Watch and Favorite Watch Watching this resources will notify you when proposed changes or new versions are created so you can keep track of improvements that have been made. Favorite Favoriting this resource allows you to save it in the “My Resources” tab of your account. There, you can easily access this resource later when you’re ready to customize it or assign it to your students. Types of Connective Tissue Connective tissues encompass a diverse array of tissue types that are involved in binding and supporting body structure and tissues. Learning Objective Describe the diverse types of connective tissue Key Points The lymphatic system is a part of the circulatory system, comprising a network of conduits called lymphatic vessels that carry a clear fluid called lymph unidirectionally towards the heart . Blood is considered a specialized form of connective tissue .

In vertebrates, it is composed of blood cells suspended in a liquid called blood plasma . The primary tissue of bone, osseous tissue, is a relatively hard and lightweight composite material, formed mostly of calcium phosphate in the chemical arrangement termed calcium hydroxylapatite. Adipose tissue or body fat is loose connective tissue composed of adipocytes. Cartilage is a flexible connective tissue found in many areas in the bodies of humans and other animals, including the joints between bones, the rib cage , the ear, the nose, the elbow, the knee , the ankle, the bronchial tubes, and the intervertebral discs . In humans, adipose tissue is located beneath the skin (subcutaneous fat), around internal organs (visceral fat), in bone marrow (yellow bone marrow), and in breast tissue. Terms Connective tissue is divided into four main categories: Connective proper Bone Blood Connective tissue proper has two subclasses: loose and dense. Loose connective tissue is divided into 1) areolar, 2) adipose, 3) reticular. Dense connective tissue is divided into 1) dense regular, 2) dense irregular, 3) elastic.

Areolar Connective Tissue These tissues are widely distributed and serve as a universal packing material between other tissues. The functions of areolar connective tissue include the support and binding of other tissues. It also helps in defending against infection . When a body region is inflamed, the areolar tissue in the area soaks up the excess fluid as a sponge and the affected area swells and becomes puffy, a condition called edema . Adipose Tissue or Body Fat This is loose connective tissue composed of adipocytes. It is technically composed of roughly only 80% fat. Its main role is to store energy in the form of lipids, although it also cushions and insulates the body. The two types of adipose tissue are white adipose tissue (WAT) and brown adipose tissue (BAT). Adipose tissue is found in specific locations, referred to as adipose depots. Yellow adipose tissue in paraffin section with lipids washed out. Reticular Connective Tissue This tissue resembles areolar connective tissue, but the only fibers in its matrix are the reticular fibers , which form a delicate network.

The reticular tissue is limited to certain sites in the body, such as internal frameworks that can support lymph nodes , spleen , and bone marrow. Dense Regular Connective Tissue This consists of closely packed bundles of collagen fibers running in the same direction. These collagen fibers are slightly wavy and can stretch a little bit. With the tensile strength of collagen, this tissue forms tendons , aponeurosis and ligaments. This tissue forms the fascia , which is a fibrous membrane that wraps around the muscles, blood vessels, and nerves . Dense Irregular Tissue This has the same structural elements as dense regular tissue, but the bundles of collagen fibers are much thicker and arranged irregularly. This tissue is found in areas where tension is exerted from many different directions. It is part of the skin dermis area and in the joint capsules of the limbs. Elastic Connective Tissue The main fibers that form this tissue are elastic in nature. These fibers allow the tissues to recoil after stretching . This is especially seen in the arterial blood vessels and walls of the bronchial tubes.

Cartilage This is a flexible connective tissue found in many areas in the bodies of humans and other animals, including the joints between bones, the rib cage, the ear, the nose, the elbow, the knee, the ankle, the bronchial tubes, and the intervertebral discs. Cartilage is composed of specialized cells called chondroblasts and, unlike other connective tissues, cartilage does not contain blood vessels. Cartilage is classified in three types: 1) elastic cartilage, 2) hyaline cartilage , and 3) fibrocartilage, which differ in the relative amounts of these three main components. Elastic Cartilage This is similar to hyaline cartilage but is more elastic in nature. Its function is to maintain the shape of the structure while allowing flexibility. It is found in the external ear (known as an auricle) and in the epiglottis . Hyaline Cartilage This is is the most abundant of all cartilage in the body. Its matrix appears transparent or glassy when viewed under a microscope. It provides strong support while providing pads for shock absorption.

It is a major part of the embryonic skeleton, the costal cartilages of the ribs, and the cartilage of the nose, trachea , and larynx. Fibrocartilage This is a blend of hyaline cartilage and dense regular connective tissue. Because it is compressible and resists tension well, fibrocartilage is found where strong support and the ability to withstand heavy pressure are required. It is found in the intervertebral discs of the bony vertebrae and knee meniscus. Bone tissue is also called the osseous tissue. The osseous tissue is relatively hard and lightweight in nature. It is mostly formed of calcium phosphate in the chemical arrangement termed calcium hydroxyapatite, which gives bones their rigidity. It has relatively high compressive strength, but poor tensile strength, and very low shear stress strength. The hard outer layer of bones is composed of compact bone tissue, so-called due to its minimal gaps and spaces. Its porosity is 5–30%. This tissue gives bones their smooth, white, and solid appearance, and accounts for 80% of the total bone mass of an adult skeleton.

Filling the interior of the bone is the trabecular bone tissue (an open cell porous network also called cancellous or spongy bone), which is composed of a network of rod and plate-like elements that make the overall organ lighter and allow room for blood vessels and marrow. Blood This is considered a specialized form of connective tissue. Blood is a bodily fluid in animals that delivers necessary substances, such as nutrients and oxygen, to the cells and transports metabolic waste products away from those same cells. It is an atypical connective tissue since it does not bind, connect, or network with any body cells. It is made up of blood cells and is surrounded by a nonliving fluid called plasma. Types of Joints Types of Joints Joints of human beings can be classified on different bases. Each base divides joints into different categories. There are three types of classifications of joints; Structural classification, Functional classification, and Regional classification. Lets have a look at all of these. Structural classification: Fibrous joints: In this type of joints the bones are joined together by means of fibrous tissue. Due to the presence of fibrous tissue these joints are either immovable or permit movement to a very little extent.

Fibrous joints are further divided into the following subtypes; Sutures: These are peculiar to skull and are immovable. According to the shape of the bony margin the sutures may be; Plane sutures Schindylesis Types of Sutures Syndesmosis: In this type of fibrous joints the bones are connected with interosseus ligament for example the inferior tibiofibular joint. Inferior tibiofibular joint Gomphosis: These are also known as peg and socket joints. Examples are tooth in the socket. Gomphosis (Teeth in their Sockets) Cartilaginous joints: In this type of joints there is a piece of cartilage between the bones which hold the bones together and makes a joint. Cartilaginous joints are further divided into the following subtypes; Primary cartilaginous joints: (synchondrosis): In this subtype the bones are united by a plate of hyaline cartilage so that the joint is immovable and strong. These joints are temporary in nature because after a certain age the cartilaginous plate is replaced by the bone.

Examples of this type of joints are joint between the epiphyses and diaphysis of a growing long bone, the costochondral joint and the first chondrosternal joint. Joint between epiphysis and diaphysis with intervening epiphyseal plate of cartilage Secondary cartilaginous joints: (symphysis): These are also known as fibro-cartilaginous joints. There articular surface is covered by a thin layer of hyaline cartilage and the bones are united by fibro-cartilage. These joints are permanent and persist throughout the life of an individual. Typically the secondary cartilaginous joints occur in the median plane of the body and permit limited movements because of compressible pad of cartilage in them. The thickness of the fibro-cartilage in these joints is directly related to the range of movement the joint offers. Examples of this type of joints are; symphysis pubis, manubrio-sternal joint and intervertebral joints between the vertebral bodies. Symphysis Pubis Synovial joints: Synovial joints are most evolved and therefore most mobile type of joints. Visit the page: Synovial Joints for more detail.

Functional classification: Immovable joints: (Synarthroses) They are fixed joints at which there is no movement. The articular surfaces are joined by tough fibrous tissue. Often the edges of the bones are dovetailed into one another as in the sutures of the skull. Partially moveable joints: (Amphiarthroses) They are joints in which slight movement is possible. A pad of cartilage lies between the bone surface and there is a fibrous capsule to hold the bone and cartilage in place. The cartilages of such joints also act as shock absorbers for example the intervertebral discs between the bodies of vertebrae where the cartilage is strengthened by extra collagen fibers. Freely moveable joints: (Diarthroses) They are the synovial joints of structural classification. They are freely moveable though at some of them the movement is restricted by the shape of the articulating surfaces and by the ligaments which hold them together. These ligaments are of elastic connective tissue.

Regional classification: Skull type: They are the joints of the skull and are immovable Vertebral type: They are the joints of vertebral column and are slightly moveable Limb type: They are the joints of upper and lower limbs and are freely moveable. Share this page: Anatomy and Physiology - Tissues of the Human Body Tissues of the Human Body Topic Review on "Title": Tissue in the human body: Epithelial: Is made of cells arranged in a continuous sheet with one or more layers, has apical & basal surfaces. A basement membrane is the attachment between the basal surface of the cell & the underlying connective tissue. Two types of epithelial tissues: (1) Covering & lining epithelia and (2) Glandular Epithelium. The number of cell layers & the shape of the cells in the top layer can classify epithelium. Simple Epithelium - one cell layer Stratified epithelium - two or more cell layers Pseudostratified Columnar Epithelium - When cells of an epithelial tissue are all anchored to the basement Membrane but not all cells reach the apical surface.

Glandular Epithelium – (1) Endocrine: Release hormones directly into the blood stream and (2) Exocrine - Secrete into ducts. Connective: contains many different cell types including: fibroblasts, macrophages, mast cells, and adipocytes. Connective Tissue Matrix is made of two materials: ground substance - proteins and polysaccharides, fiber – reticular, collagen and elastic. Classification of Connective Tissue: Loose Connective - fibers & many cell types in gelatinous matrix, found in skin, & surrounding blood vessels, nerves, and organs. Dense Connective - Bundles of parallel collagen fibers& fibroblasts, found in tendons& ligaments. Cartilage - Cartilage is made of collagen & elastin fibers embedded in a matrix glycoprotein & cells called chondrocytes, which was found in small spaces.

Cartilage has three subtypes: Hyaline cartilage – Weakest, most abundant type, Found at end of long bones, & structures like the ear and nose, Elastic cartilage- maintains shape, branching elastic fibers distinguish it from hyaline and Fibrous Cartilage - Strongest type, has dense collagen & little matrix, found in pelvis, skull & vertebral discs. Muscle: is divided into 3 categories, skeletal, cardiac and smooth. Skeletal Muscle – voluntary, striated, striations perpendicular to the muscle fibers and it is mainly found attached to bones. Cardiac Muscle – involuntary, striated, branched and has intercalated discs Smooth Muscle – involuntary, nonstriated, spindle shaped and is found in blood vessels & the GI tract. Nervous: Consists of only two cell types in the central nervous system (CNS) & peripheral nervous system (PNS): Neurons - Cells that convert stimuli into electrical impulses to the brain, and Neuroglia – supportive cells. Neurons – are made up of cell body, axon and dendrites.

There are 3 types of neurons: Motor Neuron – carry impulses from CNS to muscles and glands, Interneuron - interpret input from sensory neurons and end responses to motor neurons Sensory Neuron – receive information from environment and transmit to CNS. Neuroglia – is made up of astrocytes, oligodendrocytes, ependymal cells and microglia in the CNS, and schwann cells and satellite cells in the PNS. Development: All tissues of the body develop from the three primary germ cell layers that form the embryo: Mesoderm – develops into epithelial tissue, connective tissue and muscle tissue. Ectoderm - develops into nervous tissue and epithelial tissue. Endoderm – develops into epithelial tissue. Cell Junctions: Tight Junctions - Form a seal between cells, define apical and basal sides of an epithelial cell Gap Junctions - An open junction between two cells, which allows ions, & small molecules to pass freely between the cells. Adherens Junctions - Link actin cytoskeletal elements in two cells. Desmosomes - Link keratin filaments in adjoining cells and resist shearing forces.

Hemidesmosomes - Anchor keratin fibers in epithelial cells to the basement membrane through integrin anchors. Rapid Study Kit for "Title": Flash Movie Review Cheat Sheet "Title" Tutorial Summary : This tutorial covers the four main types of tissue in the human body. It also includes a description of the anatomical location of those tissues within the body. All 4 types of tissue originate from 3 primary layers in the developing human embryo. There are a number of cell junctions used by the various tissue types for contact with surrounding cells and the basement membrane, communication and for structural integrity. Tutorial Features: Specific Tutorial Features: A detailed description of the epithelial tissue in the body is presented including a histological description, subtype classification and location within organs and glands and the function. Series Features: Concept map showing inter-connections of new concepts in this tutorial and those previously introduced. Definition slides introduce terms as they are needed. Visual representation of concepts Examples given throughout to illustrate how the concepts apply. A concise summary is given at the conclusion of the tutorial. "Title" Topic List: The four types of tissue in the human body: A tissue is a group of cells that is from similar embryological origin and is specialized for a particular function.

Four types: epithelial, connective, muscle and nervous. Epithelial Tissues of the Human Body: Muscle Tissue Cardiac muscle Smooth muscle The Vertebral Column - Joints - Vertebrae - Vertebral Structure The Vertebral Column Last Updated: December 23, 2016 Contents The vertebral column is a vertical series of approximately 33 small bones (known as vertebrae), which are separated by intervertebral discs. It can be separated into five different regions, with each region characterised by a different vertebral structure. In this article, we shall look at the anatomy of the vertebral column – its structure, joints and ligaments. Functions The vertebral column has four main functions: Protection – encloses and protects the spinal cord within the spinal canal. Support – carries the weight of the body above the pelvis. Axis – forms the central axis of the body. Movement – has roles in both posture and movement. Adapted from work by Pereru [CC BY-SA 3.0], via Wikimedia Commons Fig 1 – The vertebral column viewed from the side. The five different regions are shown and labelled.

Vertebral Structure All vertebrae share a basic common structure. They each consist of a vertebral body, situated anteriorly, and a posterior vertebral arch. Vertebral Body The vertebral body is the anterior part of the vertebrae. It is the weight-bearing component, and its size increases as the vertebral column descends (having to support increasing amounts of weight). The superior and inferior aspects of the vertebral body are lined with hyaline cartilage. Adjacent vertebral bodies are separated by a fibrocartilginous intervertebral disc. © 2015-2016 TeachMeAnatomy.com [CC-BY-NC-ND 4.0] Fig 1.2 – Herniation of an intervertebral disc. The intervertebral disc is a fibrocartilaginous cylinder that lies between the vertebrae, joining them together. They act to permit the flexibility of the spine, and also act as a shock absorber. In the lumbar and thoracic regions they are wedge shaped, supporting the curvature of the spine. There are two regions in the vertebral disc; the nucleus pulposus and annulus fibrosus.

The annulus fibrosis is tough and collagenous, surrounding the nucleus pulposus. The nucleus pulposus is jelly-like, and is located posteriorly. In a herniation of the intervertebral disc, the nucleus pulposus ruptures, breaking through the annulus fibrosus. This most commonly occurs in a poste, putting pressure on the spinal cord, resulting in a variety of neurological and muscular symptoms. Vertebral Arch The vertebral arch refers to the lateral and posterior parts of the vertebrae. With the vertebral body, the vertebral arch forms an enclosed hole, called a vertebral foramen. The foramina of the all vertebrae line up to form the vertebral canal, which encloses the spinal cord. The vertebral arches have a number of bony prominences, which act as attachment sites for muscles and ligaments: Pedicles: There are two of these, one left and one right. They point posteriorly, meeting the flatter laminae. Lamina: The bone between the transverse and spinal processes. Transverse processes: These extend laterally and posteriorly away from the pedicles. In the thoracic vertebrae, the transverse processes articulate with the ribs.

Articular processes: At the junction of the lamina and the pedicles, superior and inferior processes arise. These articulate with the articular processes of the vertebrae above and below. Spinous processes: Posterior and inferior projection of bone, a site of attachment for muscles and ligaments. Fig 1.3 – Superior view of a lumbar vertebrae, showing its characteristic features. Classifications of Vertebrae Fig 1.3 – Distinguishing features of a cervical vertebrae. Note the triangular shape of the vertebral foramen. There are seven cervical vertebrae in the human body. They have three main distinguishing features: The spinous process bifurcates into two parts, and so is known as a bifid spinous process. There are two transverse foramina, one in each transverse process. These conduct the vertebral arteries. The vertebral foramen is triangular in shape There are some cervical vertebrae that are unique. C1 and C2 (called the atlas and axis respectively), are specialised to allow for the movement of the head. The C7 vertebrae has a much longer spinous process, which does not bifurcate. For more on the cervical spine, click here .

Thoracic Vertebrae The twelve thoracic vertebrae are medium-sized, and increase in size as they move down the back. Their main function is to articulate with ribs, producing the bony thorax . Each thoracic vertebrae has two ‘demi facets‘ on each side of its vertebral body. These articulate with the head of the respective rib, and the rib inferior to it. On the transverse processes of the thoracic vertebrae there is a costal facet for articulation with its respective rib. The spinous processes are slanted inferiorly and anteriorly. This offers increased protection to the spinal cord, preventing an object like a knife entering the spinal canal through the intervertebral discs. In contrast to the cervical vertebrae, the vertebral foramen is circular. For more on the thoracic spine, click here . Fig 1.3 – Lateral view of a thoracic vertebrae. Lumbar Vertebrae These are the largest of the vertebrae, of which there are five. They act to support the weight of the upper body, and have various specialisations to enable them do this. Lumbar vertebrae have very large vertebral bodies, which are kidney-shaped.

They lack the characteristic features of other vertebrae, with no transverse foramina, costal facets, or bifid spinous processes. However, like the cervical vertebral, they have a triangular shaped vertebral foramen. Sacrum and Coccyx © 2015-2016 TeachMeAnatomy.com [CC-BY-NC-ND 4.0] Fig 1.4 – Diagram of the sacrum and coccyx, articulating with the pelvic bones The sacrum is a collection of five fused vertebrae. It is described as an upside down triangle, with the apex pointing inferiorly. On the lateral walls of the sacrum are facets, for articulation with the pelvis at the sacro-iliac joints. The coccyx is a small bone, which articulates with the apex of the sacrum. It is recognised by its lack of vertebral arches. Due to the lack of vertebral arches, there is no vertebral canal, and so the coccyx does not transmit the spinal cord. Joints For every vertebrae, there are five articulations. The vertebral bodies indirectly articulate with each other, and the articular processes also form joints.

The vertebral body joints are cartilaginous joints, designed for weight-bearing. The articular surfaces are covered by hyaline cartilage, and are connected by a fibrocartilage intervertebral disc. There are two ligaments that strengthen these joints; the anterior and posterior longitudinal ligaments. The anterior longitudinal ligament is thick and prevents hyperextension of the vertebral column. The posterior longitudinal ligament is weaker and prevents hyperflexion. The joints between the articular facets are called facet joints. These allow for some gliding motions between the vertebrae. They are strengthened by various ligaments: Ligamentum Flavum: extends from lamina to lamina. Interspinous and Supraspinous ligaments: These join the spinous processes together. The interspinous ligaments attach between processes, and the supraspinous ligaments attach to the tips. Intertransverse ligaments: extends between transverse processes. Clinical Relevance: Abnormal Morphology of the Spine Fig 1.5 – Radiograph of scoliosis of the spine.

There are several clinical syndromes resulting from an abnormal curvature of the spine: Kyphosis: Excessive thoracic curvature, causing a hunchback deformity. Lordosis: Excessive lumbar curvature, causing a swayback deformity. Scoliosis: A lateral curvature of the spine, usually of unknown cause. Cervical Spondylosis: A decrease in the size of the intervertebral foramina, usually due to degeneration of the joints of the spine. The smaller size of the intervertebral foramina puts pressure on the exiting nerves, causing pain. Spine Anatomy Video Collectively, the vertebral bodies comprise the boney building blocks of the spine. They are stacked on top of each other with a disc in between each one. All of the vertebral bodies act as a support column to hold up the spine. This column supports about half of the weight of the body, with the other half supported by the muscles. Each area of the spine has some differences in the form and function of vertebral bodies and how they are attached to adjacent structures. Vertebral Bodies in the Cervical Spine (Neck) Cervical Spine Anatomy Video The cervical spine has seven vertebral bodies (segments).

The top two segments are unique: The first cervical segment (called the atlas) is a ring that does not have a vertebral body. It is attached to the second vertebral body (the axis), which acts as a post that the first vertebral ring rotates around. Most of the rotation in the neck is located in these top two segments. Like the rest of the spine, the next five vertebral segments have three joints at each segment, including one disc in the front and paired facet joints in the back. Unlike the rest of the spine, the segments in the cervical spine contain openings in each vertebral body for arteries to carry blood to the brain (vertebral artery running through the transverse foramen). Lumbar Spine Anatomy Video The thoracic spine has twelve vertebral bodies. These structures have very little motion because they are firmly attached to the ribs and sternum (breastbone). Because there is little motion, this region of the spine is not usually a source of back pain, although the junction between the spine and the ribs (costovertebral junction) can be a source of pain.

Vertebral Bodies in the Lumbar Spine (Lower Back) The lumbar spine has five vertebral bodies that extend from the lower thoracic spine (upper back) to the sacrum (bottom of the spine). The vertebral bodies of the lower back are the largest of the spine because they bear the majority of the body's weight. The paired facet joints on the back of the vertebral segments are aligned so that they allow flexion/extension but not a lot of rotation. Most causes of back pain originate in the lumbar spine. In This Article: Spine Anatomy Interactive Video Vertebral Components of the Lumbar Spine The thick oval segment of bone forming the front of the vertebral segment is the vertebral body. Each segment of the lumbar spine is comprised of the following structures: The vertebral bodies are attached to a bony arch through which all the nerve roots run. The vertebral arch is comprised of two pedicles, the short stout processes that extend from the sides of the vertebral body and two laminae, the broad flat plates that project from the pedicles and join in a triangle to form a hollow archway (the foramen).

The vertebral arches are interconnected by paired facet joints, which in combination with the disc, create a three joint complex at each vertebral motion segment. This three-joint complex at each vertebral segment (the facet joint) allows for motion in flexion, extension, rotation, and lateral bending. The facet joints have cartilage on each surface and a capsule around them. The cartilage can degenerate as one ages, and lead to degenerative arthritis. The spinous process protrudes from the junction of the two laminae and these are the ridges that can be felt through the skin along the back of the spine. Transverse processes project from the junction of the pedicles and lamina. The structures of the vertebral arch protect the spinal nerves that run through the spinal canal. A back surgery known as a lumbar laminectomy involves the removal of the laminae to gain access to the vertebral canal. Lower Back Motion and Back Pain Fifty percent of flexion (bending forward) occurs at the hips, and fifty percent occurs at the lumbar spine (lower back).

The motion is divided between the five motion segments in the lower back, although a disproportionate amount of the motion is at L4-L5 (lumbar segment 4 and 5) and L3-L4 (lumbar segment 3 and 4). Consequently, these two segments of the lower back are the most likely to break down with degeneration. As these segments break down they can become unstable with an excess of motion creating lower back pain . There are a number of non-surgical treatments available to help manage the low back pain, and a surgical fusion can help alleviate the back pain by stopping the motion. Vertebral Compression Fractures and Back Pain Since they are major load bearing structures, vertebral bodies are also prone to developing compression fractures , particularly in patients with osteoporosis (which weakens the bone). These fractures can lead to chronic back pain and progressive misalignment or deformity of the spine. Over time, a misalignment or deformity in the spine places stress on muscles, tendons, ligaments, and bones throughout the back and can result in impaired balance or walking ability.

Cartilage Cartilage Science Main Index Cartilage is a connective tissue found in many areas of the body such as joints between bones (e.g., elbow, knee and ankle), rib cage, ear, nose, bronchial tubes, and intervertebral discs. Read on to learn more about cartilage, and its role in the muscular system. On this page: Top of Page Cartilage Cartilage is not as rigid as bone, but is less flexible than muscle. It provides structure and support to other body tissues, and provides cushioning between joints. There are three types of cartilage: hyaline cartilage, elastic cartilage, and fibrocartilage. Hyaline cartilage can be found on the end of bones at joints, on the end of ribs, and on the larynx, trachea, and bronchi. Elastic cartilage is found in the outer ear, larynx, and epiglottis. As the name implies, it is more elastic than the other forms of cartilage. This elastic nature provides greater flexibility so it can withstand repeated bending. Bend your outer ear and you can feel elastic cartilage at work.

Fibrocartilage can be found in intervertebral discs, meniscus (e.g., knee joint), and the jaw joint. It is flexible, and yet has the highest tensile strength of the cartilage types. This strength under compression provides for effective cushioning between vertebral discs, and other joints subject to considerable pressure. Pre-Lab Reading Introduction Connective tissue is a term used to describe the tissue of mesodermal origin that that forms a matrix beneath the epithelial layer and is a connecting or supporting framework for most of the organs of the body. This lab will focus on the so-called connective tissue proper and cartilage; the next lab will focus on bone. Overview of Connective Tissue In contrast to epithelia, connective tissue is sparsely populated by cells and contains an extensive extracellular matrix consisting of protein fibers, glycoproteins, and proteoglycans. The function of this type of tissue is to provide structural and mechanical support for other tissues, and to mediate the exchange of nutrients and waste between the circulation and other tissues. These tissues have two principal components, an extracellular matrix and a variety of support cells. These two components will be the focus of this lab.

Most frequently, the different types of connective tissues are specified by their content of three distinguishing types of extracellular fibers: collagenous fibers, elastic fibers, and reticular fibers. Ground Substance The ground substance is an aqueous gel of glycoproteins and proteoglycans that occupies the space between cellular and fibrillar elements of the connective tissue. It is characterized by a gel-like viscous consistency and is polyanionic. The characteristics of the ground substance determine the permeability of the connective tissue layer to solutes and proteins. Collagenous Fibers Collagenous fibers consist of types I, II, or III collagen and are present in all types of connective tissue. Collagenous connective tissue is divided into two types, based upon the ratio of collagen fibers to ground substance: Loose (areolar connective tissue) is the most abundant form of collagenous connective tissue. It occurs in small, elongated bundles separated by regions that contain ground substance. Dense connective tissue is enriched in collagen fibers with little ground substance. If the closely packed bundles of fibers are located in one direction, it is called regular; if oriented in multiple directions, it is referred to as irregular.

An example of regular dense connective tissue is that of tendons; an example of irregular dense connective tissue is that of the dermis. Reticular Fibers Reticular fibers are composed of type III collagen. Unlike the thick and coarse collagenous fibers, reticular fibers form a thin reticular network. Such networks are widespread among different tissues and form supporting frameworks in the liver, lymphoid organs, capillary endothelia, and muscle fibers. Elastic Fibers Elastic fibers contain the protein elastin, which co-polymerizes with the protein fibrillin. These fibers are often organized into lamellar sheets, as in the walls of arteries. Dense, regular, elastic tissue characterizes ligaments. Elastic fibers are stretchable because they are normally disorganized – stretching these fibers makes them take on an organized structure. Cells of the Connective Tissue Proper Although the connective tissue has a lower density of cells than the other tissues you will study this year, the cells of these tissues are extremely important. Fibroblasts are by far the most common native cell type of connective tissue. The fibroblast synthesizes the collagen and ground substance of the extracellular matrix.

These cells make a large amount of protein that they secrete to build the connective tissue layer. Some fibroblasts have a contractile function; these are called myofibroblasts. Chondrocytes and osteocytes form the extracellular matrix of cartilage and bone. More details and chondrocytes can be found later in this laboratory; osteocytes will be covered in the Laboratory on Bone. The macrophage is the connective tissue representative of the reticuloendothelial, or mononuclear phagocyte, system. This system consists of a number of tissue-specific, mobile, phagocytic cells that descend from monocytes - these include the Kupffer cells of the liver, the alveolar macrophages of the lung, the microglia of the central nervous system, and the reticular cells of the spleen. You will encounter each of these later in the course; for now, make sure you recognize that they all descend from monocytes, and that the macrophage is the connective tissue version. Macrophages are indistinguishable from fibroblasts, but can be recognized when they internalize large amounts of visible tracer substances like dyes or carbon particles.

Macrophages phagocytose foreign material in the connective tissue layer and also play an important role as antigen presenting cells, a function that you will learn more about in Immunobiology. Mast cells are granulated cells typically found in connective tissue. These cells mediate immune responses to foreign particles. In particular, they release large amounts of histamine and enzymes in response to antigen recognition. This degranulation process is protective when foreign organisms invade the body, but is also the cause of many allergic reactions. White fat cells are specialized for the storage of triglyceride, and occur singly or in small groups scattered throughout the loose connective tissue. They are especially common along smaller blood vessels. When fat cells have accumulated in such abundance that they crowd out or replace cellular and fibrous elements, the accumulation is termed adipose tissue. These cells can grow up to 100 microns and usually contain once centrally located vacuole of lipid - the cytoplasm forms a circular ring around this vacuole, and the nucleus is compressed and displaced to the side. The function of white fat is to serve as an energy source and thermal insulator. Brown fat cells are highly specialized for temperature regulation.

These cells are abundant in newborns and hibernating mammals, but are rare in adults. They have numerous, smaller lipid droplets and a large number of mitochondria, whose cytochromes impart the brown color of the tissue. The electron transport chain of these mitochondria is disrupted by an uncoupling protein, which causes the dissipation of the mitochondrial hydrogen ion gradient without ATP production. This generates heat. Cartilage Cartilage is a specialized form of connective tissue produced by differentiated fibroblast-like cells called chondrocytes. It is characterized by a prominent extracellular matrix consisting of various proportions of connective tissue fibers embedded in a gel-like matrix. Chondrocytes are located within lacunae in the matrix that they have built around themselves. Individual lacunae may contain multiple cells deriving from a common progenitor. Lacunae are separated from one another as a result of the secretory activity of the chondrocytes. A highly fibrous, organized, dense connective tissue capsule known as the perichondrium surrounds cartilage. The fibroblast-like cells of this layer have chondrogenic potentiality, and are responsible for the enlargement of cartilage plates by appositional growth.

Appositional growth involves cell division, differentiation, and secretion of new extracellular matrix, thereby contributing mass and new cells at the cartilage surface. It is in contrast to interstitial growth, in which new matrix is deposited within mature cartilage. Three kinds of cartilage are classified according to the abundance of certain fibers and the characteristics of their matrix: Hyaline cartilage has a matrix composed of type II collagen and chondromucoprotein, a copolymer of chondroitin sulfates A and C with protein. Its high concentration of negatively-charged sulfate groups makes it appear intensely basophilic under H&E. This cartilage is found in the nose, tracheal rings, and where the ribs join the sternum. Fibrocartilage is distinguished by its high content and orderly arrangement of type I collagen fibers. It is typically located in regions where tendons attach to bones, the intervertebral discs, and the pubic symphysis. Elastic cartilage is characterized by the presence of abundant elastic fibers and is quite cellular. It is made up of type II collagen and is located in the auricle of the ear and the epiglottis.

Pre-Lab Quiz Review the four primary types of collagen and where they are typically found. Answer: Type 1 - Bone, Ligaments, Skin, Tendons. Type 2 - Cartilage. Type 3 - Reticular Fibers. Type 4 - Basement Membrane What is the difference between white and brown adipose tissue? What makes white fat "white" and brown fat "brown" under the microscope? Answer: White adipose tissue is composed of large cells with prominent central vacuoles. It is white because the lipid is washed away during fixation and the vacuoles appear white under the microscope. Brown adipose tissue has smaller cells with many lipid droplets and mitochondria. It is brown because of the large number of cytochromes present. Distinguish the three kinds of cartilage. What type of collagen are they made of, and where are they found? Answer: Hyaline cartilage – type II collagen – nose, tracheal rings, end of ribs. Fibrocartilage - type I collagen - tendons, intervertebral discs. Elastic cartilage - type II collagen - ear and epiglottis.

How would you distinguish a fibroblast, macrophage, and mast cell under the light microscope? Answer: Fibroblast may be very basophilic because it has a lot of RER, and you may actually be able to see it releasing collagen. Macrophages are mononuclear cells that are generally nondescript, although they are easily identifiable if they have been actively phagocytosing particles. Mast cells have a characteristic granulated appearance. Slides Please select whether to view the slides in study mode or quiz mode. In study mode, the images will contain labels and a description. In quiz mode, labels and description will be hidden. What is Articular Cartilage? (with pictures) What is Articular Cartilage? Last Modified Date: 28 December 2016 Copyright Protected: Top 10 amazing movie makeup transformations Articular cartilage is a white, smooth tissue which covers the ends of bones in joints. It enables bones of a joint to easily glide over one another with very little friction. This establishes easy movement. Many areas of the body can contain this kind of cartilage. Joints between the bones, knee, elbow, and rib cage are some typical locations.

Cartilage is a connective tissue that is stiff yet flexible. Some of the main types include fibrous, elastic, and hyaline. Fibrous cartilage may be found in such areas as between vertebral discs of the spinal cord. The outer ear, nose, and larynx are some locations of elastic. Hyaline cartilage, also referred to as articular cartilage, covers joint surfaces and additionally may be found in the shoulder and hips as well. Acting as a cushion between joints, cartilage can help distribute the load of pressure and weight over the surface of joints. It also can serve as a shock absorber. Composed mainly of water and collagen, shock absorbency can be possible by the hydration in the tissue. Proper function is enabled by the arrangement of internal components and composition. One articular cartilage function is to provide smooth and low-friction interaction between the bones of a joint. This may allow the withstanding of pressure and weight-bearing brought about by the motions of daily and athletic activities. By keeping the bones from gliding against each other, it can provide a measure of protection and a surface that is wear resistant. Tension and joint compression also may be better tolerated by this type of cartilage.

Normal wear and tear of everyday activities may cause articular cartilage damage . When cartilage wears away, the attached joints may become stiff, painful and face limited ranges of motion. Overuse, excessive weight and activity and improper alignment are some ways damage may occur. Additionally, articular cartilage injury may be caused by exercising, by playing sports, or be in conjunction with knee injuries. The fluidity of movement in the joints may be impaired by damages and injury. Extreme stress on the bones of a joint may lead to the loss of cartilage. As a result, the bones may begin to rub together which can cause a great deal of pain and discomfort. A condition known as osteoarthritis may be a result of this process. Osteoarthritis may cause a degenerating articular surface which could be debilitating. Symptoms of damage may include pain, swelling, stiffness, and a reduced range of joint movement. There also can be tenderness. Knee pain may be particularly common if the injured cartilage is in the knee. The sensation of joints catching or locking also may be a problem. If symptoms are too severe, it may be necessary to eliminate or adjust the activities which cause the most pain.

Damages may be diagnosed in a variety of ways. Plain X-rays generally are not very useful. Magnetic resonance imaging ( MRI ) scans often are used to make a diagnosis. A procedure known as arthroscopy also may be used. This involves making a keyhole to look directly inside the joint with a small camera. Generally, there is no direct blood supply to the cartilage. If it is damaged or injured, an articular cartilage repair may be done with surgery. This may depend on the location of the injury as well as the extent of damage. Early detection and treatment can prevent further damage and the onset of other problems such as osteoarthritis. A doctor may make a proper diagnosis and help to decide the best treatment options for damages and injuries. Ad

Question: What is the name of the structural tissue found in the ear, the nose, and in between the vertebral discs?
Answer: Cartilage