Bladder Anatomy: Difference between revisions
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== Description == | == Description == | ||
[[File:Deterusor muscle.jpeg|thumb|250x250px|Detrusor muscle]] | [[File:Deterusor muscle.jpeg|thumb|250x250px|Detrusor muscle]] | ||
It is a hollow muscular, elastic, subperitoneal organ, , located at the lesser [[Pelvis|pelvic]] cavity, it collects the urine that is filtered through the [[kidney]] through ureters to be evacuated/ voided later on. | |||
It can accommodate about 1000 ml of urine with average about 400-600 ml | It can accommodate about 1000 ml of urine with an average of about 400-600 ml which varies from one to another. The outer layer of the bladder wall is formed of smooth involuntary muscle fibers (detrusor muscles), it contracts at urination to empty the bladder. | ||
=== '''Anatomical parts of the bladder | === '''Anatomical parts of the bladder'' === | ||
When it is filled it is like an oval, formed of four parts. The neck is the constricted part, located inferiorly and leads to urethra. The apex is anterosuperior | When it is filled it is like an oval, formed of four parts. The neck is the constricted part, located inferiorly, and leads to the urethra. The apex is anterosuperior and points to the abdominal wall. The base/ fundus is located posteriorly, it is triangular-shaped its tip points backward. The body of the bladder is the main part of the bladder and is located between the apex and fundus<ref>Shermadou ES, Rahman S, Leslie SW. Anatomy, abdomen and pelvis, bladder.2018.</ref>. | ||
'''The trigon''' is a triangular region at the base of the bladder, lined with smooth muscle, collagen, and elastin to a lesser degree. Located between the internal-urethral meatus and the two ureteral orifices<ref>Hickling DR, Sun TT, Wu XR. [https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4566164/ Anatomy and physiology of the urinary tract: relation to host defense and microbial infection. Urinary tract infections]: Molecular pathogenesis and clinical management. 2017 Feb 15:1-25.</ref>. | '''The trigon''' is a triangular region at the base of the bladder, lined with smooth muscle, collagen, and elastin to a lesser degree. Located between the internal-urethral meatus and the two ureteral orifices<ref>Hickling DR, Sun TT, Wu XR. [https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4566164/ Anatomy and physiology of the urinary tract: relation to host defense and microbial infection. Urinary tract infections]: Molecular pathogenesis and clinical management. 2017 Feb 15:1-25.</ref>. | ||
{{#ev:youtube|UkTG6ncnZFg}}<ref>Anatomic Wisdom. General Features of the Urinary Bladder | |||
. Available from: http://www.youtube.com/watch?v=UkTG6ncnZFg [last accessed 3/2/2023]</ref> | |||
=== '''Urethral sphincters''' === | === '''Urethral sphincters''' === | ||
'''Internal urethral sphincter''' | '''Internal urethral sphincter''' | ||
It is formed of smooth involuntary muscle fibbers under the control of the [[Autonomic Nervous System|autonomic nervous system]], it contains alpha-adrenergic receptors its stimulation helps to fill the bladder. In | It is formed of smooth involuntary muscle fibbers under the control of the [[Autonomic Nervous System|autonomic nervous system]], it contains alpha-adrenergic receptors its stimulation helps to fill the bladder. In females, it is formed by the bladder neck and the proximal urethra (the urethra in females is about 4 -5 cm while in males it is bout 20cm in length)<ref name=":0">Sam P, Jiang J, LaGrange CA. Anatomy, abdomen and pelvis, sphincter urethrae. InStatPearls [Internet] 2021 Nov 5. StatPearls Publishing.</ref>. | ||
'''External urethral sphincter''' | '''External urethral sphincter''' | ||
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=== Nerve === | === Nerve === | ||
[[Parasympathetic System|Parasympathetic]] (s2-s4): responds to stretch receptors of the bladder wall and it is responsible for detrusor contraction to empty the bladder. The [[Pudendal Nerve|pudendal nerve]] is a somatic parasympathetic innervates the external urethral sphincter and helps to voluntary control emptying the bladder. | [[Parasympathetic System|Parasympathetic]] (s2-s4): responds to stretch receptors of the bladder wall and it is responsible for detrusor contraction to empty the bladder. The [[Pudendal Nerve|pudendal nerve]] is a somatic parasympathetic that innervates the external urethral sphincter and helps to voluntary control the emptying of the bladder. | ||
[[Sympathetic Nervous System|Sympathetic]] (t12-l2): store the urine as it | [[Sympathetic Nervous System|Sympathetic]] (t12-l2): store the urine as it causes relaxation of the detrusor muscle of the bladder. | ||
=== Artery === | === Artery === | ||
Branches from internal iliac artery; superior and inferior vesicle arteries. | Branches from internal iliac artery; superior and inferior vesicle arteries. | ||
Small branches from obturator and inferior gluteal artery. | Small branches from the obturator and inferior gluteal artery. | ||
=== Lymphatic drainage === | === Lymphatic drainage === | ||
The neck and fundus of bladder through internal, sacral and common iliac lymph nodes. | The neck and fundus of the bladder through internal, sacral, and common iliac lymph nodes. | ||
The superolateral aspect of the bladder through the external iliac lymph nodes. | The superolateral aspect of the bladder is through the external iliac lymph nodes. | ||
== Clinical relevance == | == Clinical relevance == | ||
Revision as of 03:43, 3 February 2023
Original Editor - User Name
Top Contributors - Khloud Shreif and David Olukayode
Description[edit | edit source]
It is a hollow muscular, elastic, subperitoneal organ, , located at the lesser pelvic cavity, it collects the urine that is filtered through the kidney through ureters to be evacuated/ voided later on.
It can accommodate about 1000 ml of urine with an average of about 400-600 ml which varies from one to another. The outer layer of the bladder wall is formed of smooth involuntary muscle fibers (detrusor muscles), it contracts at urination to empty the bladder.
'Anatomical parts of the bladder[edit | edit source]
When it is filled it is like an oval, formed of four parts. The neck is the constricted part, located inferiorly, and leads to the urethra. The apex is anterosuperior and points to the abdominal wall. The base/ fundus is located posteriorly, it is triangular-shaped its tip points backward. The body of the bladder is the main part of the bladder and is located between the apex and fundus[1].
The trigon is a triangular region at the base of the bladder, lined with smooth muscle, collagen, and elastin to a lesser degree. Located between the internal-urethral meatus and the two ureteral orifices[2].
Urethral sphincters[edit | edit source]
Internal urethral sphincter
It is formed of smooth involuntary muscle fibbers under the control of the autonomic nervous system, it contains alpha-adrenergic receptors its stimulation helps to fill the bladder. In females, it is formed by the bladder neck and the proximal urethra (the urethra in females is about 4 -5 cm while in males it is bout 20cm in length)[4].
External urethral sphincter
It is consisted of skeletal muscle fibers, it is under voluntary control, and contains nicotinic receptors[4].
Innervation[edit | edit source]
Nerve[edit | edit source]
Parasympathetic (s2-s4): responds to stretch receptors of the bladder wall and it is responsible for detrusor contraction to empty the bladder. The pudendal nerve is a somatic parasympathetic that innervates the external urethral sphincter and helps to voluntary control the emptying of the bladder.
Sympathetic (t12-l2): store the urine as it causes relaxation of the detrusor muscle of the bladder.
Artery[edit | edit source]
Branches from internal iliac artery; superior and inferior vesicle arteries.
Small branches from the obturator and inferior gluteal artery.
Lymphatic drainage[edit | edit source]
The neck and fundus of the bladder through internal, sacral, and common iliac lymph nodes.
The superolateral aspect of the bladder is through the external iliac lymph nodes.
Clinical relevance[edit | edit source]
Detrusor sphincter dyssynergia
Atonic bladder
Neurogenic bladder
Treatment[edit | edit source]
Resources[edit | edit source]
- ↑ Shermadou ES, Rahman S, Leslie SW. Anatomy, abdomen and pelvis, bladder.2018.
- ↑ Hickling DR, Sun TT, Wu XR. Anatomy and physiology of the urinary tract: relation to host defense and microbial infection. Urinary tract infections: Molecular pathogenesis and clinical management. 2017 Feb 15:1-25.
- ↑ Anatomic Wisdom. General Features of the Urinary Bladder . Available from: http://www.youtube.com/watch?v=UkTG6ncnZFg [last accessed 3/2/2023]
- ↑ 4.0 4.1 Sam P, Jiang J, LaGrange CA. Anatomy, abdomen and pelvis, sphincter urethrae. InStatPearls [Internet] 2021 Nov 5. StatPearls Publishing.
