What Innervates the external sphincter?

What Innervates the external sphincter?

Innervation. The external anal sphincter receives somatic innervation from the inferior anal nerve, a branch of the pudendal nerve (S2-S4). As a result, this muscle is under voluntary control.

Which sphincter controls bladder?

The internal urethral sphincter regulates involuntary control of urine flow from the bladder to the urethra, and the external urethral sphincter provides voluntary control of urine flow from the bladder to the urethra.

What is the sphincter ani Externus?

The Sphincter ani externus (External sphincter ani) is a flat plane of muscular fibers, elliptical in shape and intimately adherent to the integument surrounding the margin of the anus. It measures about 8 to 10 cm. in length, from its anterior to its posterior extremity, and is about 2.5 cm. broad opposite the anus.

What type of tissue are the sphincters composed of quizlet?

Its part of the inner surface of the canal; it is composed of concentric layers of circular muscle tissue and is not under voluntary control.

Where is the Pectinate line?

anal canal
Anatomical terminology The pectinate line (dentate line) is a line which divides the upper two-thirds and lower third of the anal canal. Developmentally, this line represents the hindgut-proctodeum junction.

What is a sphincter Vesicae?

Noun. 1. musculus sphincter vesicae – the sphincter muscle of the urinary bladder; made up of a thickened muscular layer of bladder around the urethral opening. bladder sphincter. urinary bladder – a membranous sac for temporary retention of urine.

What do you mean by micturition?

Urination
Micturition: Urination; the act of urinating.

What type of tissue are the sphincters composed of?

circular muscle tissue
The internal sphincter is part of the inner surface of the canal; it is composed of concentric layers of circular muscle tissue and is not under voluntary control. The external sphincter is a layer of voluntary (striated) muscle encircling the outside wall of the anal canal…

What is the perineum made of?

The perineum has a roof formed by the pelvic diaphragm and a floor of fascia and skin. It also contains the muscles and neurovasculature associated with urogenital structures and the anus.

What are sphincters quizlet?

sphincter. a circular muscle surrounding, and able to close, a body opening. pyloric valve. the circular muslce of the lower stomach that regulates the flow of partly digested food into the small intestine.

What does the pectinate line separate?

The pectinate line (dentate line) is a line which divides the upper two-thirds and lower third of the anal canal. Developmentally, this line represents the hindgut-proctodeum junction.

What structures are below the pectinate line?

Below the Pectinate Line The middle rectal artery is a branch of the internal iliac artery, while the inferior rectal artery is a branch of the internal pudendal artery. The lymphatic drainage below the pectinate line is to the superficial inguinal lymph nodes.

What are the sphincters of the bladder and urethra?

Anatomy, Abdomen and Pelvis, Sphincter Urethrae – StatPearls – NCBI Bookshelf The urethral sphincter is a muscular structure that regulates the outflow of urine from the bladder into the urethra. There are 2 urethral sphincters, the external and internal urethral sphincters.

How is the urethral sphincter related to the levator ani?

The external urethral sphincter is closely related to the levator ani, deep transverse perineal and rectourethral muscles. The puboperineal component of the levator ani muscle, forms an open circle around the external sphincter creating a hiatus at the ventral aspect.

Where is the sphincter located in the male body?

Contraction of urethrovaginal sphincter leads to constriction of both the urethra and vagina. In males, the external urethral sphincter is located at the same level as the membranous urethra and is composed of circular muscle fibers. The external urethral sphincter is continuous with the isthmus of the prostate.

How does Onuf’s nucleus affect the urethral sphincter?

When stimulated, Onuf’s nucleus acts to increase the resting tone in the external urethral sphincter, the skeletal muscle is contracted and urination is stopped or slowed. Central nervous system inhibition of Onuf’s nucleus results in relaxation of the external urethral sphincter.

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