Information: - Semen, also known as seminal fluid, is an organic fluid that may contain spermatozoa. It is secreted by the gonads (sexual glands) and other sexual organs of male or hermaphroditic animals and can fertilize female ova. In humans, seminal fluid contains several components besides spermatozoa: proteolytic and other enzymes as well as fructose are elements of seminal fluid which promote the survival of spermatozoa, and provide a medium through which they can move or "swim". - The urinary bladder is a hollow muscular organ that collects urine from the kidneys before disposal by urination. A hollow muscular, and distensible (or elastic) organ, the bladder sits on the pelvic floor. Urine enters the bladder via the ureters and exits via the urethra. The typical human bladder capacity is between 300 and (10.14 and ). - In mammals, the vagina is a muscular and tubular part of the female genital tract, which in humans extends from the vulva to the cervix. The outer vaginal opening may be partly covered by a membrane called the hymen. At the deep end, the cervix (neck of the uterus) bulges into the vagina. The vagina allows for sexual intercourse and childbirth, and channels menstrual flow, which occurs periodically as part of the menstrual cycle. - Urine is a liquid by-product of metabolism in the bodies of many animals, including humans. It is expelled from the kidneys and flows through the ureters to the urinary bladder, from which it is soon excreted from the body through the urethra during urination. - A penis (plural "penises" or "penes" ) is the primary sexual organ that male animals use to inseminate sexually receptive mates (usually females and hermaphrodites respectively) during copulation. Such organs occur in many animals, both vertebrate and invertebrate, but males do not bear a penis in every animal species, and in those species in which the male does bear a so-called penis, the penes in the various species are not necessarily homologous. For example, the penis of a mammal is at most analogous to the penis of a male insect or barnacle. - Urination is the release of urine from the urinary bladder through the urethra to the urinary meatus outside of the body . It is also known medically as micturition , voiding , uresis , or , rarely , emiction , and known colloquially by various names including tinkling , peeing , weeing , and pissing . In healthy humans ( and many other animals ) the process of urination is under voluntary control . In infants , some elderly individuals , and those with neurological injury , urination may occur as a reflex . It is normal for adult humans to urinate up to seven times during the day . In some animals , in addition to expelling waste material , urination can mark territory or express submissiveness . Physiologically , urination involves coordination between the central , autonomic , and somatic nervous systems . Brain centers that regulate urination include the pontine micturition center , periaqueductal gray , and the cerebral cortex . In male placental mammals , urine is ejected through the penis . In female placental mammals , urine is ejected through the vulva or pseudo-penis . - In human anatomy, the ureters are tubes made of smooth muscle fibers that propel urine from the kidneys to the urinary bladder. In the adult, the ureters are usually long and ~34mm in diameter. Histologically, the ureter contains transitional epithelium and an additional smooth muscle layer in the more distal one-third to assist with peristalsis. - Animals are multicellular, eukaryotic organisms of the kingdom Animalia (also called Metazoa). The animal kingdom emerged as a basal clade within Apoikozoa as a sister of the choanoflagellates. Sponges are the most basal clade of animals. Animals are motile, meaning they can move spontaneously and independently at some point in their lives. Their body plan eventually becomes fixed as they develop, although some undergo a process of metamorphosis later in their lives. All animals are heterotrophs: they must ingest other organisms or their products for sustenance. - Anatomy is the branch of biology concerned with the study of the structure of organisms and their parts. Anatomy is inherently tied to embryology, comparative anatomy, evolutionary biology, and phylogeny, as these are the processes by which anatomy is generated over immediate (embryology) and long (evolution) timescales. Human anatomy is one of the basic essential sciences of medicine. - The pelvic floor or pelvic diaphragm is composed of muscle fibers of the levator ani, the coccygeus muscle, and associated connective tissue which span the area underneath the pelvis. The pelvic diaphragm is a muscular partition formed by the levatores ani and coccygei, with which may be included the parietal pelvic fascia on their upper and lower aspects. The pelvic floor separates the pelvic cavity above from the perineal region (including perineum) below. - Metabolism (from "metabol", "change") is the set of life-sustaining chemical transformations within the cells of living organisms. The three main purposes of metabolism are the conversion of food/fuel to energy to run cellular processes, the conversion of food/fuel to building blocks for proteins, lipids, nucleic acids, and some carbohydrates, and the elimination of nitrogenous wastes. These enzyme-catalyzed reactions allow organisms to grow and reproduce, maintain their structures, and respond to their environments. The word metabolism can also refer to the sum of all chemical reactions that occur in living organisms, including digestion and the transport of substances into and between different cells, in which case the set of reactions within the cells is called intermediary metabolism or intermediate metabolism. - The urinary meatus, also known as the external urethral orifice, is the opening or meatus of the urethra. It is the point where urine exits the urethra in males and in females, and also where semen exits the urethra in males. The meatus has varying degrees of sensitivity to touch. The meatus is located on the glans penis in males and in the vulval vestibule in females. - Urination is the release of urine from the urinary bladder through the urethra to the outside of the body. It is the urinary system's form of excretion. It is also known medically as micturition, voiding, uresis, or, rarely, emiction, and known colloquially by various names including tinkling, peeing, weeing, whizzing, pissing, and draining the snake. - A liquid is a nearly incompressible fluid that conforms to the shape of its container but retains a (nearly) constant volume independent of pressure. As such, it is one of the four fundamental states of matter (the others being solid, gas, and plasma), and is the only state with a definite volume but no fixed shape. A liquid is made up of tiny vibrating particles of matter, such as atoms, held together by intermolecular bonds. Water is, by far, the most common liquid on Earth. Like a gas, a liquid is able to flow and take the shape of a container. Most liquids resist compression, although others can be compressed. Unlike a gas, a liquid does not disperse to fill every space of a container, and maintains a fairly constant density. A distinctive property of the liquid state is surface tension, leading to wetting phenomena. - The kidneys are two bean-shaped organs found on the left and right sides of the body in vertebrates. They filter the blood in order to make urine, to release and retain water, and to remove waste. They also control the ion concentrations and acid-base balance of the blood. Each kidney feeds urine into the bladder by means of a tube known as the ureter. - In anatomy, the urethra (from Greek "ourthr") is a tube that connects the urinary bladder to the urinary meatus for the removal of fluids from the body. In male placental mammals, the urethra travels through the penis, and carries semen as well as urine. In female placental mammals, the urethra is shorter and emerges at the female external urethral orifice above the vaginal opening. What entity does 'urination' has the relation 'subclass of' with?
excretion