Difference between revisions of "Urethra - Anatomy & Physiology"
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| + | {{toplink | ||
| + | |backcolour = C1F0F6 | ||
| + | |linkpage =Urinary System - Anatomy & Physiology | ||
| + | |linktext =URINARY SYSTEM | ||
| + | |maplink = Urinary System (Content Map) - Anatomy & Physiology | ||
| + | |pagetype =Anatomy | ||
| + | }} | ||
| + | <br> | ||
==Introduction== | ==Introduction== | ||
This muscular tube is the connection between the bladder and the external environment and plays a vital role in concious urinary continence. | This muscular tube is the connection between the bladder and the external environment and plays a vital role in concious urinary continence. | ||
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==Female== | ==Female== | ||
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* This is often at the vestibulo vaginal junction | * This is often at the vestibulo vaginal junction | ||
* Only urine passes through it | * Only urine passes through it | ||
| + | * The urethral submucosa has a network of veins which may contribute to continence by forming a kind of erectile tissue. | ||
* Length and diameter is species specific | * Length and diameter is species specific | ||
** Short and wide - mare | ** Short and wide - mare | ||
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==Male== | ==Male== | ||
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* Empties at tip of penis | * Empties at tip of penis | ||
* Divided into 3 parts | * Divided into 3 parts | ||
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The '''urethralis''' muscle runs the entire length of the urethra and forms the external urethral sphincter. | The '''urethralis''' muscle runs the entire length of the urethra and forms the external urethral sphincter. | ||
| − | Unlike the [[ | + | Unlike the [[Bladder - Anatomy & Physiology#Internal Urethral Sphincter|internal sphincter]] the external sphincter is composed of striated muscle fibres which are under the voluntary control of the somatic nervous system. |
=====Somatic Motor Supply - External Urethral Sphincter===== | =====Somatic Motor Supply - External Urethral Sphincter===== | ||
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==Blood Supply== | ==Blood Supply== | ||
| − | Blood Supply comes from the Urethral Artery | + | Blood Supply comes from the Urethral Artery |
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Revision as of 11:25, 6 September 2008
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Introduction
This muscular tube is the connection between the bladder and the external environment and plays a vital role in concious urinary continence.
Female
- Empties at the external urethral orifice on the ventral wall of the vagina
- This is often at the vestibulo vaginal junction
- Only urine passes through it
- The urethral submucosa has a network of veins which may contribute to continence by forming a kind of erectile tissue.
- Length and diameter is species specific
- Short and wide - mare
- 2 fossa - bitch
- Suburethral diverticulum - cow and sow
Male
- Empties at tip of penis
- Divided into 3 parts
- Pre-prostatic - bladder neck to seminal hillock
- Prostatic portion - openings of deferant, vesicular and prostatic ducts
- Penile portion - ischial arch to penile tip
- Note the first 2 combined are called the pelvic portion
Muscles of the Urethra
The urethralis muscle runs the entire length of the urethra and forms the external urethral sphincter.
Unlike the internal sphincter the external sphincter is composed of striated muscle fibres which are under the voluntary control of the somatic nervous system.
Somatic Motor Supply - External Urethral Sphincter
- S1-S2
- Pudendal Nerve
- No synapse
- Innervates the urethral skeletal muscle - external urethral sphincter
- Function is to contract and retain urine
Blood Supply
Blood Supply comes from the Urethral Artery