Bowel, Bladder and Sexual Function Flashcards
Urinary Bladder
- Hollow organ with strong muscular walls (smooth muscle)
- Detrusor Muscle (smooth ms in wall of bladder) forms the bladder wall
- Lies mostly inferior to the peritoneum
- Lies in the deep pelvis posterior to the pubic symphysis when empty in adults
- With filling it ascends into the anterior abdominal region and enters the false pelvis
- Always contains some urine, even after emptying
Children up to 6; bladder lies in the abdomen and descends with age.
- Some references report Bladder capacity up to 1000 ccs… and some as low as 500 ccs, with an urge to micturate at around 300 ccs; dependent on the person.
Anatomic Regions of Bladder
- Apex-Anterior aspect near pubic symphysis
- Fundus-base of bladder formed by its posterior wall; opposite the apex
- Body-major portion of bladder between apex and fundus
- Neck-the fundus and & inferolateral surfaces of bladder meet here
- Trigone-an area of the bladder defined by a smooth internal surface formed by the two ureters and the internal urethral orifice. Sensitive to expansion/stretch.
Ureters
- Two 25 – 30 cm in length, muscular tubes run through the abdomen along the pelvic brim
- Run obliquely through a gap in the muscular wall of the urinary bladder
- A flap valve is formed as the ureters enter the bladder…thus contraction of the bladder musculature acts as a sphincter, preventing urine reflux back towards the kidney during bladder emptying
Ureter Innervation
•Innervation of ureters: via the autonomic (ANS) plexus
-Sympathetic fibers
Afferent pain information follows the sympathetic fibers towards spinal cord segments T11-L2 (only go to L2)
- Refers pain ipsilateral along subcostal, ilioinguinal and genitofemoral nn. distribution
- Includes sensory stretch to ureter as well
Parasympathetic fibers (Vagus & S2,3, 4)
-Contraction & peristaltic (for urine) motion of ureters
- The pain of a blocked ureter is excruciating and radiates to the flank, top of the thigh and labium majorus in females and in males, to the scrotum and penis.
- Renal and ureteral pain fibers are activated by stretching the collecting system and ureter. Additional pain triggers are a direct injury to the mucosa. The pain stimuli are transmitted through sympathetic fibers and produce a typical visceral pain. The reflex-like activation of the subcostal nerve, genitofemoral nerve and ilioinguinal nerve produces a pain with radiating to the flanks, groin and genital region with hyperalgesia.
Kidney Stones
- The leading cause of kidney stones is a dehydration. Stones commonly have been found in those that drink less than the recommended eight to ten glasses of water a day.
- When there is not enough water to dilute the uric acid (component of urine), the pH level within the kidneys drops and becomes more acidic. An excessively acidic environment in the kidneys is conducive to the formation of kidney stones.
Referred Visceral Pain
hHeart (C8-T4) on Left
hLungs (T2-5)
- Esophagus (T4-5)
- Liver (T6-9) right
- Ovaries & fallopian tubes (T11-L1)
- Kidneys (T10-T11)
- Ureters (T11-L2)
- Colon (T8-L2)
- Bladder(T11-L3)
- Rectum, ovaries, prostate (S2-5)
- Myocardial Infarction pain is thought to originate when visceral sensory nerve endings in the myocardium are irritated and then ascends up the sympathetic trunk and enter the spinal cord through the dorsal roots of the upper four Thoracic nerves (T1-T4) and therefore the pain is felt in the sensory dermatomes supplied by these spinal nerves.
- It’s believed that there’s some spread of sensory neuronal information within the central nervous system because the pain is sometimes felt outside these dermatomes like in the face, jaw, and neck.
- In the case of inferior MI, it’s assumed that the afferents enter the spinal cord through T7, T8, T9 spinal roots thereby given referred pain the epigastric dermatomes.
- Since both the heart and the thoracic esophagus have similar visceral afferents, we should not be surprised that MI pain and pain from esophagitis may give rise to similar pain syndromes.
Male Urethra
Urethra-muscular tube 18-30 cm which leads to the external urethral orifice
- male urethra provides an exit for semen
- Male Urethra-divided into 4 parts:
- Preprostatic-contains internal urethral sphincter
- Prostatic-Prostate gland help with mobility of sperm
- Membranous-passes through the external urethral sphincter (closing)-voluntary,skeletal ms-this is why when you don’t want to pee you can hold onto your urine
- Spongy
-is smooth ms-autonomic is in charge (internal urethral sphincter, proximal to prostate gland)-this prevents backflow of semen during ejaculation
Internal Urethral Sphincter
- Involuntary sphincter of smooth muscle fibers (under ANS control)
- (Male) Prevents retrograde movement of semen into the bladder during ejaculation
•Internal urethral orifice
-Leads to the urethra
External Urethral Sphincter
- skeletal Muscle-voluntary
- Makes up part of the UG (urogential diaphragm, pierced by the urethra, consists of two muscles bilaterally: the deep transverse perineal muscles and the sphincter urethrae. The deep transverse perineal muscle arises from the ischial ramus and is inserted into the perineal body, which it supports. In the male, the sphincter urethrae, which may be fused with the deep transverse perineal muscle, arises from the inferior pubic ramus and passes medially to meet the muscle of the opposite side and surround the membranous urethra. *)
- UG diaphragm supports the contents of the deep pelvis along with the pelvic floor muscles (pelvic diaphragm)
- Ext Urethral sphincter : provides a means of stopping the escape of urine from the body.
•Under voluntary control-via somatic efferents (pudendal n. S2-S4-NOT PARASYMPATHETIC N.)
Bladder Innervation
Innervation to Bladder (sensory and motor)
- Via parasympathetic fibers (pelvic splanchnic nerves-S2,3,4-not pudendal n.) (NOT ALWAYS SPECIFICALLY PARASYMPA OR SYMPA IN GENERAL) which carry the following neural messages….
- Visceral afferent: Sensory to the detrusor muscle to determine level of stretch and relays pain from lower bladder
- Motor to the detrusor muscles-causes smooth muscle wall of bladder to contract
- Inhibition to the internal sphincter (so it relaxes and urine will flow)
- Via sympathetic fibers (hypogastric plexus through T11 through L2 portions of spinal cord)
- Visceral afferents: sensation of Pain from the superior aspect of the bladder
*not under voluntary control! Is autonomic, but its under our control to dampen when exactly to relieve*
Micturition Reflex
- Visceral afferent fibers stimulated by bladder stretch (~350-400 mls) causes the bladder to contract reflexively while the internal sphincter relaxes & urine flows into the urethra
- With training & intact neural pathway from supraspinal centers, we can suppress this reflex until it is convenient
- E.g. External urethral sphincter remains contracted (voluntary control-pudendal nerve, not parasympathetic S2,S3,S4, just plain old motor and sensory)
Innervation Take Home
- pudendal is not parasympathetic, is motor and sensory plain old
- parasympa n fibers arrive from portions of the cord, pudendal has motor and sensory but not parasympa, pelvic splanchnics are what carry the S2,S3,S4 (parasympa only), thoracic and cervical splanchnics are (sympa only)
- Internal urethral sphincter-pelvic splanchnic
*as soon as bladder becomes full, it contracts, internal urethral sphincter relaxes, and external relaxes and urine will flow
Mictruition Qs
- when bladder becomes stretched theres an increase in APs travelling from? The urinary bladder to the sacral region
- who innervates the bladder? Parasympa neurons from spinal cord to bladder
- who innervates the external urinary sphincter? Somatic motor neuron
- if urination not convenient, brain sends impulses down spinal cors to inhibit mictruition reflex? True
Testes
- male sex organs that lie within the scrotum; produce sperm and the male sex hormone, testosterone, are outside of scrotal sac bc of temp, is lil cooler
- Semen: The fluid that is released through the penis during orgasm. Semen is made up of fluid and of sperm. The fluid comes from the prostate gland, seminal vesicle and other sex glands. The sperm are manufactured in the testicles. The seminal fluid helps transport the sperm during orgasm. Seminal fluid contains sugar as an energy source for sperm.
Epididymis
-Portion of the male genital tract next to the testes where sperm maturation is partially accomplished. Receives sperm from the testes and continues as the ductus deferens
Ductus Deferens
•Ductus deferens (aka vas deferens)-A thick walled tubular structure running from each testis into the ejaculatory duct. These structures carry sperm from the epididymis towards the penis.
Seminal Vesicles
•Seminal vesicles-produce semen, a fluid that activates and protects the sperm after it has left the penis during ejaculation
Prostate
•Prostate- gland in the male that surrounds a portion of the urethra. It secretes an alkaline liquid that neutralizes acid in the urethra and stimulates motility of the sperm.
Bulbourethal glands (Cowpers glands)
•Bulbourethral glands (Cowper’s glands) two small, rounded, pea sized bodies posterolateral to the membranous portion of the urethra. They discharge a component of seminal fluid into the urethra (not seen in this view); location= CG
Ejaculatory Duct
•Ejaculatory duct-begins at the seminal vesicles, passes through the prostate, and empties into the urethra. During ejaculation, semen passes through the EJ ducts
Female Urethra
- 4-6 cm in length which leads to the external urethral orifice
- Lies anterior to the vagina
- Passes with the vagina through the pelvic diaphragm & then through the external urethral sphincter
- External Urethral Sphincter under voluntary control
- Innervation: branches from pudendal n. (S2-4, not parasympa) to external urethral sphincter
- Sensory Afferents (pain) from urethra run in the pelvic splanchnic nerves (parasymp)
- Internal Urethral sphincter: literature suggests no function in female or it does not exist b/c function specific to male(prevent backflow of semen during ejaculation)
Female Internal Genital Organs
•Vagina-7-9 cm long extending from the cervix of the uterus passing between the levator ani muscles
- Located between the urethra and rectum
- Innervation: sympathetics; parasympathetics (S2-4 via pelvic splanchnics)
- Uterus
- Uterine (fallopian) tubes
- Ovaries
- Support: Round Ligament/Broad Ligament of Uterus
