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Tunica Vaginalis
The tunica vaginalis is the pouch of serous membrane that covers the testes. It is derived from the vaginal process of the peritoneum, which in the fetus precedes the descent of the testes from the abdomen into the scrotum. After its descent, that portion of the pouch which extends from the abdominal inguinal ring to near the upper part of the gland becomes obliterated; the lower portion remains as a shut sac, which invests the surface of each testis, and is reflected on to the internal surface of the scrotum; hence it may be described as consisting of a visceral and a parietal lamina. Visceral lamina The visceral lamina (lamina visceralis) covers the greater part of the testis and epididymis, connecting the latter to the testis by means of a distinct fold. From the posterior border of the gland it is reflected on to the internal surface of the scrotum. Parietal lamina The parietal lamina (lamina parietalis) is far more extensive than the visceral, extending upward for some di ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Testis
A testicle or testis (plural testes) is the male reproductive gland or gonad in all bilaterians, including humans. It is homologous to the female ovary. The functions of the testes are to produce both sperm and androgens, primarily testosterone. Testosterone release is controlled by the anterior pituitary luteinizing hormone, whereas sperm production is controlled both by the anterior pituitary follicle-stimulating hormone and gonadal testosterone. Structure Appearance Males have two testicles of similar size contained within the scrotum, which is an extension of the abdominal wall. Scrotal asymmetry, in which one testicle extends farther down into the scrotum than the other, is common. This is because of the differences in the vasculature's anatomy. For 85% of men, the right testis hangs lower than the left one. Measurement and volume The volume of the testicle can be estimated by palpating it and comparing it to ellipsoids of known sizes. Another method is to use calipe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Epididymis
The epididymis (; plural: epididymides or ) is a tube that connects a testicle to a vas deferens in the male reproductive system. It is a single, narrow, tightly-coiled tube in adult humans, in length. It serves as an interconnection between the multiple efferent ducts at the rear of a testicle (proximally), and the vas deferens (distally). Anatomy The epididymis is situated posterior and somewhat lateral to the testis. The epididymis is invested completely by the tunica vaginalis (which is continuous with the tunica vaginalis covering the testis). The epididymis can be divided into three main regions: * The head ( la, caput). The head of the epididymis receives spermatozoa via the efferent ducts of the mediastinum testis, mediastinium of the testis at the superior pole of the testis. The head is characterized histologically by a thick epithelium with long stereocilia (described below) and a little smooth muscle. It is involved in absorbing fluid to make the sperm more concentra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrocele
A hydrocele is an accumulation of serous fluid in a body cavity. A hydrocele testis, the most common form of hydrocele, is the accumulation of fluids around a testicle. It is often caused by fluid collecting within a layer wrapped around the testicle, called the tunica vaginalis, which is derived from peritoneum. Provided there is no hernia present, it goes away without treatment in the first year. Although hydroceles usually develop in males, rare instances have been described in females in the Canal of Nuck. Primary hydroceles may develop in adulthood, particularly in the elderly and in hot countries, by slow accumulation of serous fluid. This is presumably caused by impaired reabsorption, which appears to be the explanation for most primary hydroceles, although the reason remains obscure. A hydrocele can also be the result of a plugged inguinal lymphatic system caused by repeated, chronic infection of ''Wuchereria bancrofti'' or ''Brugia malayi'', two mosquito-borne parasi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mesothelioma
Mesothelioma is a type of cancer that develops from the thin layer of tissue that covers many of the internal organs (known as the mesothelium). The most common area affected is the lining of the lungs and chest wall. Less commonly the lining of the abdomen and rarely the sac surrounding the heart, or the sac surrounding the testis may be affected. Signs and symptoms of mesothelioma may include shortness of breath due to fluid around the lung, a swollen abdomen, chest wall pain, cough, feeling tired, and weight loss. These symptoms typically come on slowly. More than 80% of mesothelioma cases are caused by exposure to asbestos. The greater the exposure the greater the risk. As of 2013, about 125 million people worldwide have been exposed to asbestos at work. High rates of disease occur in people who mine asbestos, produce products from asbestos, work with asbestos products, live with asbestos workers, or work in buildings containing asbestos. Asbestos exposure and the ons ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Seminiferous Tubule
Seminiferous tubules are located within the testes, and are the specific location of meiosis, and the subsequent creation of male gametes, namely spermatozoa. Structure The epithelium of the tubule consists of a type of sustentacular cells known as Sertoli cells, which are tall, columnar type cells that line the tubule. In between the Sertoli cells are spermatogenic cells, which differentiate through meiosis to sperm cells. Sertoli cells function to nourish the developing sperm cells. They secrete androgen-binding protein, a binding protein which increases the concentration of testosterone. There are two types: convoluted and straight, convoluted toward the lateral side, and straight as the tubule comes medially to form ducts that will exit the testis. The seminiferous tubules are formed from the testis cords that develop from the primitive gonadal cords, formed from the gonadal ridge. Function Spermatogenesis, the process for producing spermatozoa, takes place in the s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lobules Of Testis
The glandular structure of the testis consists of numerous lobules. Their number, in a single testis, is estimated by Berres at 250, and by Krause at 400. Anatomic studies have demonstrated figures of 250–290 for the same. They differ in size according to their position, those in the middle of the gland being larger and longer. The lobules are conical in shape, the base being directed toward the circumference of the organ, the apex toward the mediastinum testis. Each lobule is contained in one of the intervals between the fibrous septa The Southeastern Pennsylvania Transportation Authority (SEPTA) is a regional public transportation authority that operates bus, rapid transit, commuter rail, light rail, and electric trolleybus services for nearly 4 million people in five cou ... which extend between the mediastinum testis and the tunica albuginea, and consists of from one to three, or more, minute convoluted tubes, the tubuli seminiferi. Additional images File:Gray114 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tunica Albuginea Of Testis
The tunica albuginea is the fibrous tissue covering of the testis. It is a dense blue-grey membrane, composed of bundles of white fibrous connective tissue, from which it derives its name '' albuginea'', which interlace in every direction. Structure The tunica albuginea is a layer of fibrous tissue capsule covering the testis. It is covered by the tunica vaginalis, except at the points of attachment of the epididymis to the testis, and along its posterior border, where the spermatic vessels enter the gland. It is thicker than the tunica albuginea of the ovary. The tunica albuginea is applied to the tunica vasculosa over the glandular substance of the testis, and, at its posterior border, is reflected into the interior of the gland, forming an incomplete vertical septum, called the mediastinum testis (corpus Highmori). Additional images File:Gray1145.png, Transverse section through the left side of the scrotum and the left testis. File:Gray1114.png, Section of a genital c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Testicle
A testicle or testis (plural testes) is the male reproductive gland or gonad in all bilaterians, including humans. It is homologous to the female ovary. The functions of the testes are to produce both sperm and androgens, primarily testosterone. Testosterone release is controlled by the anterior pituitary luteinizing hormone, whereas sperm production is controlled both by the anterior pituitary follicle-stimulating hormone and gonadal testosterone. Structure Appearance Males have two testicles of similar size contained within the scrotum, which is an extension of the abdominal wall. Scrotal asymmetry, in which one testicle extends farther down into the scrotum than the other, is common. This is because of the differences in the vasculature's anatomy. For 85% of men, the right testis hangs lower than the left one. Measurement and volume The volume of the testicle can be estimated by palpating it and comparing it to ellipsoids of known sizes. Another method is to use cal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mesorchium
The testes, at an early period of foetal life, are placed at the back part of the abdominal cavity, behind the peritoneum, and each is attached by a peritoneal fold, the mesorchium, to the mesonephros. See also * mesentery The mesentery is an organ that attaches the intestines to the posterior abdominal wall in humans and is formed by the double fold of peritoneum. It helps in storing fat and allowing blood vessels, lymphatics, and nerves to supply the intesti ... * mesovarium Mesorchium is the fibrous sheath which attaches vascular and avascular structures of spermatic cord together. References External links * - "Inguinal Region, Scrotum and Testes: Coverings of the Testis" * Animal developmental biology {{Portal bar, Anatomy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mesothelial
The mesothelium is a membrane composed of simple squamous epithelial cells of mesodermal origin, which forms the lining of several body cavities: the pleura ( pleural cavity around the lungs), peritoneum ( abdominopelvic cavity including the mesentery, omenta, falciform ligament and the perimetrium) and pericardium (around the heart). Mesothelial tissue also surrounds the male testis (as the tunica vaginalis) and occasionally the spermatic cord (in a patent processus vaginalis). Mesothelium that covers the internal organs is called visceral mesothelium, while one that covers the surrounding body walls is called the parietal mesothelium. The mesothelium that secretes serous fluid as a main function is also known as a serosa. Origin Mesothelium derives from the embryonic mesoderm cell layer, that lines the coelom (body cavity) in the embryo. It develops into the layer of cells that covers and protects most of the internal organs of the body. Structure The mes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Viscus
In biology, an organ is a collection of tissues joined in a structural unit to serve a common function. In the hierarchy of life, an organ lies between tissue and an organ system. Tissues are formed from same type cells to act together in a function. Tissues of different types combine to form an organ which has a specific function. The intestinal wall for example is formed by epithelial tissue and smooth muscle tissue. Two or more organs working together in the execution of a specific body function form an organ system, also called a biological system or body system. An organ's tissues can be broadly categorized as parenchyma, the functional tissue, and stroma, the structural tissue with supportive, connective, or ancillary functions. For example, the gland's tissue that makes the hormones is the parenchyma, whereas the stroma includes the nerves that innervate the parenchyma, the blood vessels that oxygenate and nourish it and carry away its metabolic wastes, and the conne ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tunica (biology)
In biology, a tunica (, ; ) is a layer, coat, sheath, or similar covering. The word came to English from the New Latin of science and medicine. Its literal sense is about the same as that of the word ''tunic'', with which it is cognate. In biology one of its senses used to be the taxonomic name of a genus of plants, but the nomenclature has been revised and those plants are now included in the genus ''Petrorhagia''. In modern biology in general, ''tunica'' occurs as a technical or anatomical term mainly in botany and zoology. It usually refers to membranous structures that line or cover particular organs. In many such contexts ''tunica'' is used interchangeably with ''tunic'' according to preference. An organ or organism that has a tunic(a) may be said to be ''tunicate'', as in a ''tunicate bulb''. This adjective ''tunicate'' is not to be confused with the noun ''tunicate'', which refers to a member of the subphylum '' Tunicata''. Botanical and related usages In botany there are s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
