| Urethra | |
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| Female anatomy. (Urethra labeled at bottom left. ) | |
| Latin | Female urethra: urethra feminina Male urethra: urethra masculina |
| Gray's | subject #256 1234 |
| Precursor | Urogenital sinus |
| MeSH | urethra |
| Dorlands/Elsevier | u_03/12838693 |
In anatomy, the urethra (from Greek ουρήθρα - ourethra) is a tube which connects the urinary bladder to the outside of the body. Latin ( lingua Latīna, laˈtiːna is an Italic language, historically spoken in Latium and Ancient Rome. Gray's Anatomy the Respiratory apparatus ( Apparatus Respiratorius Respiratory system Respiratory apparatus Embryology (from Greek grc ἔμβρυον embryon, "unborn embryo" and grc -λογία -logia) is the study of the development The urogenital sinus (also known as the persistent cloaca) is a part of the human body only present in the Development of the urinary and reproductive organs. Medical Subject Headings ( MeSH) is a huge Controlled vocabulary (or metadata system for the purpose of indexing journal articles and books Elsevier, the world's largest Publisher of Medical and Scientific literature, forms part of the Reed Elsevier group Anatomy (from the Greek anatomia, from ana separate apart from and temnein, to cut up cut open is a branch of Biology that is the consideration Greek (el ελληνική γλώσσα or simply el ελληνικά — "Hellenic" is an Indo-European language, spoken today by 15-22 million people mainly In Anatomy, the urinary bladder is a hollow muscular, and distensible (or elastic organ that sits on the Pelvic floor in Mammals It is the The urethra has an excretory function in both sexes to pass urine to the outside, and also a reproductive function in the male, as a passage for semen. Urine is a liquid waste product of the body secreted by the Kidneys by a process of filtration from Blood and Excreted through the Urethra. Physiological aspects Internal and external fertilization Depending on the Species, spermatozoa can fertilize
The external urethral sphincter is a striated muscle that allows voluntary control over urination. The urethral sphincter is a collective name for the Muscles used to control the flow of Urine (micturition from the Urinary bladder. Urination, also known as micturition, voiding, and more rarely emiction, is the process of disposing Urine from the Urinary bladder
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Anatomy
Female urethra
In the human female, the urethra is about 1 1/2-2 inches (3-5 cm) long and opens in the vulva between the clitoris and the vaginal opening, extending from the internal to the external urethral orifice. The vulva (from Latin, vulva, plural vulvae or vulvas; see etymology) is the region of the external genital organs The clitoris is a sexual organ that is present only in Female Mammals In humans the visible button-like portion is located near the Anterior The vagina (from Latin, literally " Sheath " or " Scabbard " is a fibromuscular tubular tract leading from the Uterus It is placed behind the symphysis pubis, imbedded in the anterior wall of the vagina, and its direction is obliquely downward and forward; it is slightly curved with the concavity directed forward. Its lining is composed of stratified squamous epithelium, which becomes transitional near the bladder. The urethra consists of three coats: muscular, erectile, and mucous, the muscular layer being a continuation of that of the bladder. Between the superior and inferior fascia of the urogenital diaphragm, the female urethra is surrounded by the Sphincter urethae. Somatic innervation of the external urethral sphincter is supplied by the pudendal nerve. The uro-genital sinus may be divided into three component parts. The first of these is the cranial portion which is continuous with the allantois and forms the bladder proper. The pelvic part of the sinus forms the prostatic urethra and epithelium as well as the membranous urethra and bulbo urethral glands in the male and the membranous urethra and part of the vagina in females.
Male urethra
In the human male, the urethra is about 8 inches (15 cm) long and opens at the end of the penis. The penis (plural penises, penes The inside of the urethra has a spiral groove (like rifling in a gun barrel), which makes the urine flow in a wide stream. Rifling refers to the Helix -shaped pattern in the barrel of a Firearm, which imparts a spin to a Projectile around its long axis
The urethra is divided into four parts in men, named after the location:
| Region | Description | Epithelium |
| pre-prostatic urethra | This is the intramural part of the urethra and varies between 0. In biology and medicine epithelium is a tissue composed of cells that line the cavities and surfaces of structures throughout the body The pre-prostatic urethra is one of the four parts of the male Urethra. 5 and 1. 5 cm in length depending the fullness of the bladder. | Transitional |
| prostatic urethra | Crosses through the prostate gland. Transitional epithelium (also known as urothelium is a type of tissue consisting of multiple layers of Epithelial cells which can contract and expand The prostatic urethra, the widest and most dilatable part of the Urethra canal is about 3 cm The prostate (from Greek προστάτης - prostates, literally "one who stands before" "protector" "guardian" is a There are several openings: (1) a small opening where sperm from the vas deferens and ejaculatory duct enters, (2) the prostatic ducts where fluid from the prostate enters, (3) an opening for the prostatic utricle, but nothing is added from it. A spermatozoon or spermatozoan ( pl spermatozoa) from the Ancient Greek σπέρμα (seed and ζῷον (living being and more commonly known The vas deferens (plural vasa deferentia also called ductus deferens, ( Latin: "carrying-away vessel" is part of the Male Anatomy The Ejaculatory ducts ( ductus ejaculatorii) are paired structures in male Anatomy, about 2 cm in length The prostatic ducts (or prostatic ductules) open into the floor of the Prostatic portion of the urethra, and are lined by two layers of Epithelium, the The prostate (from Greek προστάτης - prostates, literally "one who stands before" "protector" "guardian" is a The prostatic utricle (Latin for "pouch of the Prostate " is a small indentation located in the Prostatic urethra, at the apex of the Urethral crest These openings are collectively called the verumontanum. | Transitional |
| membranous urethra | A small (1 or 2 cm) portion passing through the external urethral sphincter. The intermediate part of male urethra ( membranous portion) is the shortest least dilatable and with the exception of the external orifice the narrowest part of the canal This is the narrowest part of the urethra. It is located in the deep perineal pouch. The deep perineal pouch (also deep perineal space) is an anatomical term that refers to the space enclosed in part by the Perineum, and located superior to the The ducts from the bulbourethral glands enter here. A bulbourethral Gland (or Cowper 's gland) is one of two small Exocrine glands present in the Reproductive system of human males | Pseudostratified columnar |
| spongy urethra (or penile urethra) | Runs along the length of the penis on its ventral (underneath) surface. A pseudostratified epithelium is a type of Epithelium that though comprising only a single layer of cells, has its cell nuclei positioned in a manner The spongy urethra ( cavernous portion of urethra, penile urethra) is the longest part of the male Urethra, and is contained in the Corpus spongiosum It is about 15-16 cm in length, and travels through the corpus spongiosum. Corpus spongiosum (Plural Corpora Spongiosa (also known as corpus cavernosum urethrae in older texts is the mass of spongy tissue surrounding the male Urethra The ducts from the urethral gland enter here. The term urethral or periurethral gland (also Littre gland after Alexis Littré, or preputial glands) is used to refer to any of the many Glands Some textbooks will subdivide the spongy urethra into two parts, the bulbous and pendulous urethra. | Pseudostratified columnar - proximally, Stratified squamous - distally |
The length of a male's urethra, and the fact it contains a number of bends, makes catheterisation more difficult. A pseudostratified epithelium is a type of Epithelium that though comprising only a single layer of cells, has its cell nuclei positioned in a manner In Anatomy, squamous epithelium (from Latin squama, "scale" is an Epithelium characterised by its most superficial layer consisting In Medicine a catheter is a tube that can be inserted into a body cavity duct or vessel
Histology
The epithelium of the urethra starts off as transitional cells as it exits the bladder. In biology and medicine epithelium is a tissue composed of cells that line the cavities and surfaces of structures throughout the body Transitional epithelium (also known as urothelium is a type of tissue consisting of multiple layers of Epithelial cells which can contract and expand Further along the urethra there are stratified columnar cells, then stratified squamous cells near the external meatus (exit hole). Stratified columnar epithelia have several layers with Columnar cells as the outermost of these In Anatomy, squamous epithelium (from Latin squama, "scale" is an Epithelium characterised by its most superficial layer consisting
There are small mucus-secreting urethral glands, that help protect the epithelium from the corrosive urine. In vertebrates mucus is a slippery secretion produced by and covering Mucous membranes It is a viscous Colloid containing Antiseptic enzymes (such as
Medical problems of the urethra
- Hypospadias and epispadias are forms of abnormal development of the urethra in the male, where the meatus is not located at the distal end of the penis (it occurs lower than normal with hypospadias, and higher with epispadias). Hypospadias is a Birth defect of the Urethra in the Male that involves an abnormally placed Urinary meatus (opening An epispadias is a rare type of malformation of the Penis in which the Urethra ends in an opening on the upper aspect (the dorsum of the penis The urinary meatus (pronounced /mē-ˈā-təs/) is the external Orifice of the Urethra, from which Urine is ejected during Urination In fields of Anatomy, anatomical terms of location are descriptive terms to help identify relative positions or directions within a species In a severe chordee, the urethra can develop between the penis and the scrotum. Presentation It is usually considered a Congenital malformation of unknown cause In some Male Mammals the scrotum - also 'scrutum' or 'scrootum' - is a protuberance of Skin and Muscle containing the Testicles
- Infection of the urethra is urethritis, said to be more common in females than males. Urethritis is inflammation of the Urethra. The main symptom is Dysuria, which is painful or difficult urination Urethritis is a common cause of dysuria (pain when urinating). In Medicine, specifically Urology, dysuria refers to painful Urination.
- Related to urethritis is so called urethral syndrome
- Passage of kidney stones through the urethra can be painful and subsequently it can lead to urethral strictures. Urethral syndrome is defined as symptoms suggestive of a lower urinary tract infection but in the absence of significant bacteruria with a conventional Pathogen. Kidney stones, also called renal calculi, are solid concretions (crystal aggregations of dissolved minerals in Urine; calculi typically form A urethral stricture is a narrowing of the Urethra caused by injury or disease such as Urinary tract infections or other forms of Urethritis.
Endoscopy of the bladder via the urethra is called cystoscopy. Endoscopy of the Urinary bladder via the Urethra is called cystoscopy
Sexual physiology
The male urethra is the conduit for semen during sexual intercourse. Sexual intercourse, in its biological sense is the act in which the male reproductive organ (in humans and other higher animals enters the female reproductive tract It also serves as a passage for urine to flow.
See also
- Perineal urethra
- Vulvovaginal health
- Urethral sponge
- G-spot
- Urethral sounding
- Urethrotomy
- External urethral orifice
- Internal urethral orifice
Additional images
 Urinary system |
 Muscles of the female perineum. A perineal urethra is a human Urethral opening that is located on the Perineum rather than at the tip of the Phallus. Vulvovaginal health is the health and sanitation of the Human Female Vulva and Vagina. The urethral sponge is a spongy cushion of tissue, found in the lower genital area of Women, that sits against both the Pubic bone The Gräfenberg spot, or G-spot, is a female Erogenous zone which when stimulated leads to high levels of sexual arousal and powerful Orgasms Sounding or urethral sounding is the medical use of probes called sounds to increase the inner diameter of the Urethra and to locate obstructions in it The internal urethral orifice is the opening of the Urinary bladder into the Urethra. |
 Transverse section of the penis. |
External links
- Histology at KUMC epithel-epith07 "Male Urethra"
Dictionary
urethra
-noun
- (anatomy) The tube through which urine exits the body and, in males, through which semen is ejaculated.
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