case 8 Flashcards
bladder
• The urinary bladder is a smooth muscle chamber composed of two main parts:
- The body – urine collects here.
- The neck - is a funnel-shaped extension of the body, passing inferiorly and anteriorly into the urogenital triangle and connecting with the urethra. The lower part of the bladder neck is also called the posterior urethra because of its relation to the urethra.
detrusor muscle
• The smooth muscle of the bladder is called the detrusor muscle.
Its muscle fibres extend in all directions.
When contracted, can the pressure inside the bladder is increased. This allows the emptying of the bladder (normal range = ≤ 15-20 cmH20)
Smooth muscle cells of the detrusor muscle fuse with one another so that low-resistance electrical pathways exist from one muscle cell to the other.
Therefore, an action potential can spread throughout the detrusor muscle, from one muscle cell to the next, to cause contraction of the entire bladder at once.
trigone of the bladder
• On the posterior wall of the bladder, lying immediately above the bladder neck, is a small triangular area called the trigone.
The mucosa of trigone is smooth, in contrast to the remaining bladder mucosa, which is folded to form rugae.
The two ureters enter the bladder at the uppermost angles of the trigone.
Each ureter, as it enters the bladder, courses obliquely through the detrusor muscle and then passes another 1-2cm beneath the bladder mucosa before emptying into the bladder.
posterior urethra
At the lowermost apex of the trigone, the bladder neck opens into the posterior urethra.
This is 2-3cm long, and its wall is composed of detrusor muscle interlaced with a large amount of elastic tissue.
The muscle in this area is called the internal sphincter.
o Its natural tone normally keeps the bladder neck and posterior urethra empty of urine and, therefore, prevents emptying of the bladder until the pressure in the main part of the bladder rises above a critical threshold.
external sphincter of the bladder
• Beyond the posterior urethra, the urethra passes through the urogenital diaphragm, which contains a layer of muscle called the external sphincter of the bladder.
This muscle is a voluntary skeletal muscle, in contrast to the muscle of the bladder body and bladder neck, which is entirely smooth muscle.
The external sphincter muscle is under voluntary control of the nervous system and can be used to consciously prevent urination even when involuntary controls are attempting to empty the bladder.
types of muscle in the bladder
- Internal sphincter = smooth muscle = involuntary control (parasympathetic)
- External sphincter = skeletal muscle = voluntary control (somatic)
- The normal urine flow = 20-50 ml/s
parasympathetic innervation of the bladder-autonomic
- the principal nerve supply of the bladder is by way of the PELVIC SPLANCHNIC NERVES, which connect with the spinal cord through the sacral plexus (S2,3,4):
Sensory nerve fibres(afferent)
These detect the degree of stretch in the bladder wall.
Stretch signals from the posterior urethra are especially strong and are mainly responsible for initiating the reflexes that cause bladder emptying.
Motor nerve fibres (efferent)
These terminate on ganglion cells located in the wall of the bladder.
Short postganglionic nerves then innervate the detrusor muscle (M3 receptor).
This aids micturition.
sympathetic innervation of the bladder-autonomic
the bladder receives sympathetic innervation from the sympathetic chain through the HYPOGASTRIC NERVES (L2).
These cause relaxation of detrusor muscle (B3 receptor) and contraction of urethra (a1 receptor), thus allowing bladder to fill.
Some sensory nerve fibres also pass by way of the sympathetic nerves and may be important in the sensation of fullness and, in some instances, pain.
somatic innervation of the bladder-voluntary
other innervation of the bladder is skeletal motor fibres transmitted through the PUDENDAL NERVE to the external sphincter.
These innervate and provide voluntary control over the skeletal muscle of the external sphincter (ACh).
Higher centres can override this contraction and cause the external sphincter to relax.
overall innervation to the bladder and its effects
• Parasympathetic nerve fibres (S2,3,4) cause:
Contraction of detrusor muscle in the body of the bladder (M3 receptor).
Relaxation of the urethra.
This aids micturition.
• Sympathetic nerve fibres (T11-L2) cause:
Relaxation of the detrusor muscle in the body of the bladder (B3 receptor).
Contraction of the urethra (a1 receptor).
This aids the filling of the bladder.
• Somatic nerve fibres (S2,3,4) cause:
Contraction of the external sphincter.
Higher centres can override this contraction and cause the external sphincter to relax.
clinical differences in male and female urethras
The female urethra is distensible because it contains considerable elastic tissue, as well as smooth muscle. It can be easily dilated without injury; consequently, the passage of catheters or cystoscopes is easier in females than in males. Infections of the urethra, and especially the bladder, are more common in women because the female urethra is short, more distensible, and is open to the exterior through the vestibule of the vagina.
female urethra
The female urethra (approximately 4 cm long and 6 mm in diameter) passes anteroinferiorly from the internal urethral orifice of the urinary bladder, posterior and then inferior to the pubic symphysis, to the external urethral orifice. The musculature surrounding the internal urethral orifice of the female bladder is not organized into an internal sphincter. In females, the external urethral orifice is located in the vestibule, the cleft between the labia minora of the external genitalia, directly anterior to the vaginal orifice. The urethra lies anterior to the vagina (forming an elevation in the anterior vaginal wall). The urethra passes with the vagina through the pelvic diaphragm, external urethral sphincter, and perineal membrane. Urethral glands are present, particularly in the superior part of the urethra. One group of glands on each side, the paraurethral glands, are homologs to the prostate. These glands have a common paraurethral duct, which opens (one on each side) near the external urethral orifice.
male urethra
The male urethra originates at the bladder neck and terminates at the urethral meatus on the glans penis. It is roughly 15-25 cm long in the adult and forms an “S” curve when viewed from a median sagittal plane in an upright, flaccid position.
The male urethra is often divided into 4 segments on the basis of its investing structures:
• Preprostatic urethra (the bladder neck).
• Prostatic urethra.
• Membranous (or intermediate) urethra.
• Spongy (or penile) urethra.
prostatic urethra
It originates in the region of the bladder neck, courses roughly 2.5 cm inferiorly, and terminates at the membranous urethra. It lies in a retropubic location and is bordered superiorly by the bladder and supported inferiorly by the external urethral sphincter muscle and the urogenital diaphragm. It is invested in the prostate
membranous urethra
The shortest and least distensible portion of the urethra. This region spans from the apex of the prostate to the bulb of the penis. It is invested in the external urethral sphincter muscle and the perineal membrane. The external sphincter is related anteriorly to the dorsal venous complex and is connected to the puboprostatic ligaments and the suspensory ligament of the penis. The external urethral sphincter muscle and the perineal membrane fix the urethra firmly to the ischial rami and inferior pubic rami, rendering this portion of the urethra susceptible to disruption with pelvic fracture.
spongey urethra
The spongy urethra is the region that spans the corpus spongiosum of the penis. It is divided into the pendulous urethra and the bulbous (or bulbar) urethra. The pendulous urethra is invested in the corpus spongiosum of the penis in the pendulous portion of the penis. The urethra is located concentrically within the corpus spongiosum. The bulbous urethra is invested in the bulb of the penis, the portion of corpus spongiosum that lies between the split corpora cavernosa in the superficial perineal space.
female urethra blood supply and innervation
Blood Supply – Urethral artery (branch of internal pudendal) and vaginal artery. The veins follow the arteries and have similar names.
Innervation – Nerves to the urethra: Vesical plexus & pudendal nerve. Nerves from the urethra: Mostly pelvic splanchnic nerves, but the termination of the urethra has signals transmitted via the pudendal nerve. All afferent nerves = S2-S4
male proximal (pre prostatic and prostatic) urethra blood supply and innervation
Blood Supply – Prostatic branches of the inferior vesical & middle rectal arteries. The veins from the proximal 2 parts of the urethra drain into the prostatic venous plexus.
Innervation – Sympathetic, parasympathetic, and visceral afferent nerve fibres run together in nerves of the prostatic plexus (arising from the inferior hypogastric plexus).
male distal (membranous and spongey) urethra blood supply and innervation
Blood Supply – Arterial branches arise from the dorsal artery of the penis. Veins accompany the arteries and have similar names.
Innervation - Membranous urethra has the same innervation as the proximal urethra. The spongy urethra has sympathetic innervation from lumbar splanchnic nerves and parasympathetic innervation from pelvic splanchnic nerves (sacral spinal cord level). It transmits visceral afferent fibres alongside the parasympathetic fibres to sacral spinal sensory ganglia. Somatic innervation is provided via the dorsal nerve of the penis (branch of pudendal nerve).
lymphatic drainage of the urethra
The lymphatic vessels of the membranous and prostatic urethrae in males and the whole of the urethra in the female, pass to the internal iliac nodes, although a few may enter the external nodes. Vessels coming from the spongy urethra drain with the glans penis into the deep inguinal nodes. Some of the vessels may enter the superficial inguinal nodes and may pass through the inguinal canal to reach the external iliac nodes.
From these nodes they drain into the lateral aortic nodes. From the nodes, efferents issue to the lumbar lymph trunk. The lumbar lymph trunks help to form the abdominal confluence of lymph ducts or the cisterna chyli. Cisterna chyli drains into thoracic duct.
micturition
• Micturition is the process by which the urinary bladder empties when it becomes filled.
• This involves two main steps:
1. The bladder fills until the tension in its walls rises above a threshold level.
2. This elicits a nervous reflex called the micturition reflex that empties the bladder or, if this fails, at least causes a conscious desire to urinate.
• Although the micturition reflex is an autonomic spinal cord reflex, it can also be inhibited or facilitated by centres in the cerebral cortex or brain stem.
transport of urine from the kidneys to ureters to bladder
- Urine that is expelled from the bladder has the same composition as fluid flowing out of the collecting ducts of the kidneys.
- Urine flows from the collecting ducts into the renal calyces, thus stretching them.
- This increases their pacemaker activity, which in turn initiates peristaltic contractions that spread to the renal pelvis and then downward along the length of the ureter, thereby forcing urine from the renal pelvis to the bladder.
• The walls of the ureters contain smooth muscle.
These are innervated by both sympathetic and parasympathetic nerves and by an intramural plexus (nerve plexus within the wall) that extends along the entire length of the ureters.
Peristaltic contractions in the ureter are enhanced by parasympathetic stimulation and inhibited by sympathetic stimulation.
• The ureters enter the bladder through the detrusor muscle in the trigone region.
The normal tone of the detrusor muscle in the bladder wall tends to compress the ureter, thereby preventing back flow of urine from the bladder when pressure builds up in the bladder during micturition or bladder compression
problems of backflow of urine
- Sometimes, the contraction of the bladder during micturition does not always lead to complete occlusion of the ureter (valve).
- As a result, some of the urine in the bladder is propelled backward into the ureter - vesicoureteral reflux.
- Such reflux can lead to enlargement (dilatation) of the ureters.
- If severe it increases the pressure in the renal calyces and the renal medulla, causing renal dysfunction.
pain sensation in the ureters - uterorenal reflex
- The ureters are well supplied with pain nerve fibres.
- When a ureter becomes blocked (e.g. by a ureteral stone), intense reflex constriction occurs, associated with severe pain.
- Also, the pain impulses cause a sympathetic reflex back to the kidney to constrict the renal arterioles, thereby decreasing urine output from the kidney.
- This effect is called the ureterorenal reflex and is important for preventing excessive flow of fluid into the pelvis of a kidney with a blocked ureter.
micturition reflex
• The micturition contractions are as a result of the micturition reflex.
• Micturition reflex:
As the bladder is filling, sensory stretch receptors in the bladder wall, especially by the receptors in the posterior urethra, initiate a stretch reflex.
Sensory signals from these stretch receptors are conducted to the sacral plexus through the ‘sensory’ afferents of the pelvic splanchnic nerves and then reflexively back to the bladder through the ‘motor’ efferent fibres of the same pelvic splanchnic nerves.
When the bladder is only partially filled, these micturition contractions usually relax and the detrusor muscles stop contracting, and pressure falls back to the baseline.
As the bladder continues to fill, the micturition reflexes become more frequent and cause greater contractions (more powerful) of the detrusor muscle.
Once a micturition reflex begins, it is “self-regenerative”.
That is, initial contraction of the bladder activates the stretch receptors to cause a greater increase in sensory impulses to the bladder and posterior urethra, which causes a further increase in reflex contraction of the bladder; thus, the cycle is repeated again and again until the bladder has reached a strong degree of contraction.
After a little while, the self-regenerative reflex begins to fatigue and the regenerative cycle of the micturition reflex ceases, permitting the bladder to relax.
full bladder and micturation
- As the bladder becomes more and more filled, micturition reflexes occur more frequently and more powerfully.
- Once the micturition reflex becomes powerful enough, it causes another reflex, which passes through the pudendal nerves to the external sphincter to inhibit it.
- If this inhibition is more potent in the brain than the voluntary constrictor signals to the external sphincter, urination will occur.
- If not, urination will not occur until the bladder fills still further and the micturition reflex becomes more powerful.
facilitation or inhibition of micturition by the brain
• The micturition reflex is a completely autonomic spinal cord reflex, but it can be inhibited or facilitated by centres in the brain.
• These centres are located in the:
1. Brainstem (pons) – these are strong facilitative and inhibitory centres.
2. Cerebral cortex – these are mainly inhibitory but can become excitatory.
1. The higher centres keep the micturition reflex partially inhibited, except when micturition is desired.
2. The higher centres can prevent micturition, even if the micturition reflex occurs, by continual tonic contraction of the external sphincter until a convenient time presents itself.
3. When it is time to urinate, the cortical centres can facilitate the sacral micturition centres to help initiate a micturition reflex and at the same time inhibit the external urinary sphincter so that urination can occur
voluntary urination
is usually initiated in the following way:
1. Voluntary contraction of abdominal muscles.
2. This increases the pressure in the bladder and allows extra urine to enter the bladder neck and posterior urethra under pressure, thus stretching their walls.
3. This stimulates the stretch receptors, which excites the micturition reflex and simultaneously inhibits the external urethral sphincter.
• Ordinarily, all the urine will be emptied, with rarely more than 5-10 ml left in the bladder
BPH terminology
Benign Prostatic Enlargement • BPE • Clinical Dx • Benign Prostatic Hyperplasia • BPH • Pathological Dx • Bladder Outflow Obstruction • BOO • Urodynamic Dx
phytotherapy
Phytotherapy is the study of the use of extracts of natural origin as medicines or health-promoting agents. Phytotherapy medicines differ from plant-derived medicines in standard pharmacology.
culture
Definition: Symbolic and learned aspects of society, including
language, custom and convention
(Abercrombie et al, 1994)
Symbolic aspects of the body influence how people experience and
respond to disease and illness
Culture influences what is perceived
to be ‘normal’ / the norms of a given society/ group
folk models and diet
People draw on popular cultural beliefs about
illness and causation, e.g.
Hypertension as folk illness: ‘high blood’
Belief that amount of blood in the body
increases or falls in volume due to diet
Low blood associated with too much salt, so
salt increased for high blood
definition of sex and gender
Sex: The biological and physical
characteristics defining males and females
Gender: a social construct defined by the
roles, behaviours, responsibilities, activities
and attributes considered appropriate within
a particular society or culture for a man or
woman
gender culture and inequalities
A woman cannot receive needed health care because norms in her community
prevent her from travelling alone to a clinic.
◦ A teenage boy dies in an accident because of trying to live up to his peers’
expectations that young men should be “bold” risk-takers.
◦ A married woman contracts HIV because societal standards encourage her husband’s
promiscuity while simultaneously preventing her from insisting on condom use.
◦ A country’s lung cancer mortality rate for men far outstrips the corresponding rate
for women because smoking is considered an attractive marker of masculinity, while
it is frowned upon in women.
gender differences in access and use of health services
Women have more routine contact with health services Cultural expectations of masculine/ feminine behaviour Social relationships Wider cultural context Preferences for consulting male/ female doctor
stigma
branding or marking. enacted is societal reaction with a discriminatory experience. felt is expected societal reactions change their self identity.
worsened health outcomes
cortesy: spread to his connections
stigma and urinary symptoms
People with urinary symptoms perceive themselves to be stigmatised for behaviours associated with urinary symptoms The stigma of frequency/ urgency is rooted in social interruption, loss of control of the body, speculation about the ‘problem’ & visibility of symptoms Men and women experience stigma related to urinary symptoms differently, and Hispanic people in particular had a tendency to keep urinary symptoms a secret from others
what can healthcare providers do about stigma
Need to deliver culturally sensitive healthcare Avoid discrimination based on assumptions about gender and sexuality Increase awareness about cultural sensitivities to promote disclosure of symptoms and other health information Assess for stigma consequences (e.g. depression and anxiety) and discuss management options
negative emotions and pain
Anxiety and depression predict postoperative pain (Arpino et al 2004; Munafó et al 2001) • Negative emotions can increase perception of pain –Experimental study: group in which negative emotion induced reported higher levels of pain (immersion of hand in hot water) (Rainville et al 2005)
influence on wound healing
Stress: associated with impaired healing (see Walburn et al 2009 for review). • E.g. Marucha et al 1998 –Dental students, punch biopsy to mouth roof 1) end of vacation, 2) exam time –On average, 3 days slower to heal during exams.
stress influence on behaviour
People high in anxiety may find it more
difficult to understand information and
follow instructions
→ could e.g. prolong procedure
information provision
Procedural information
–What, when, how?
– Reduce anxiety by eliminating unexpected
anxiety-provoking events (Ridgeway &
Matthews 1982)
• Sensory information
–What will it feel like, look like, sound like, taste like?
–Goal: reduce discrepancy between expected
and actual sensation (Johnson, 1973)
important how word things and when say it - not when on drugs,
behavioural instructions
Telling people what they should do – e.g. –After joint replacement surgery – how soon should start walking –Techniques for effective pain control with analgesia –How to move after surgery without damaging wound site.
communication behaviours
Difficult to determine anxiety/pain e.g. Johnston 1982, Marquié et al. 2003 • May be unwilling to bother staff • Pre-procedure training can facilitate patients’ communication to staff • E.g. reassure appropriate to tell staff about anxiety/pain • Teach how to communicate – e.g. how to use quick, easy rating scales
cognitive interventions
Change how a person thinks – goal: reduce negative thinking and/or anxiety – e.g.: –Reframing cognitions - training to find positive responses to worrying situations – e.g. reason for surgeon’s visit – Distraction - encourage thinking about something else
