Genitourinary System Flashcards
describe the peritoneum characteristics
serous membrane lining abdominal cavity
2 layers of mesothelium
peritoneal space inbetween 2 layers
where does the parietal peritoneum line and what is it derived from?
lines internal surface of the abdominal-pelvic cavity
derived from somatic mesoderm
what does the visceral peritoneum line?
invaginates and lines abdominal organs
what is the difference between pain in the visceral and parietal peritoneum?
visceral - poorly localised
parietal - well localised
what are the 3 intraperitoneal organs?
stomach, liver, spleen
what are the 3 main retroperitoneal organs and how are they covered by the peritoneum?
oesophagus, rectum, kidneys
peritoneum only covers anteriorly
what are the functions of the kidney?
filter waste (urine production)
regulates blood (BP/ions/pH/osmolarity/volume/glucose levels)
hormone production such as calcitrol (active vitamin D) or erythropoetin
what are the 3 structures found in the hilum?
renal artery, renal vein, ureter (forms at renal pelvis)
what does the cortex of the kidney contain and what is its function?
provides supporting tissue
contains glomeruli, bowman’s capsule and convoluted tubules
what is the function of the kidney’s medulla and how is it organised?
function - main site of filtration
organised into renal/medullary pyramids
what are the functioning units of the kidneys?
nephrons and collecting tubules
what 2 structures make up the renal corpuscle?
glomerulus and bowmans capsule
what are nephron collecting tubules comprised of?
renal corpuscle and renal tubules
what are the 4 basic steps of the nephron collecting tubules function?
filtration, reabsorption, secretion, excretion
what are renal tubules comprised of?
PCT, LoH, DCT, diuretics (Na linked)
what 3 blood vessels are located in the kidney and where do they supply?
interlobal - lobes
cortical - cortex
arcuate - between cortex/medulla
explain the calyx system
papillas link medulla pyramids to the minor calyx which drains the pyramid into a major calyx, which all connects to the renal pelvis which transports the urine to the bladder
what muscle near the kidneys is important for hip flexion?
psoas major
name the arteries that supply the area around the kidneys with blood
R/L suprarenal arteries
R/L inferior phrenic arteries
R/L renal arteries
R/L testicular/ovarian arteries
inf/sup mesenteric arteries
name the veins around the renal system responsible for blood drainage
R/L renal veins
L inferior phrenic vein
R/L testicular/ovarian veins
what is the function of the ureters?
transports urine to urinary bladder
what is a common problem of the ureters?
highly sensetive and can be blocked by kidney stones
what are the 3 main areas where kidney stones can block the ureter?
pelvoureteric junction
pelvic brim
trigone
name the layers of the urinary bladder from superficial to deep
detrusor muscle
submucosa
lamina propria
transitional epithelium
where do the ureters enter the bladder?
the ureteric meatus’
what is the trigone?
a triangular area from the orifices of the ureter openings and the urethra
what does the vas deferens connect?
testes to urethra
name the layers of the testes from superficial to deep
scrotum skin
superficial fascia
external spermatic fascia
crewmaster muscle (+ fascia)
internal spermatic fascia
parietal tunica vaginalis
visceral tunica vaginalis
tunica albuginea of testis
what are the exocrine and endocrine functions of the testes?
exocrine - sperm cells
endocrine - testosterone
what structures in the testes does the tunica albuginea form?
200-300 lobules
what does each singular lobule contain?
1-4 seminiferous tubules
what 5 structures (in order) does sperm travel through?
seminiferous tubules
straight tubules (tubulus rectus)
rete testes
efferent ductules
epididymus
where are sperm cells produced and matured?
produced - seminiferous tubules (as spermatozoa)
matured - epididymus
what are the 3 parts of the urethra?
prostatic, membranous, pendulous
what is the urethral crest and what is its function?
long fold in posterior urethra wall stopping sperm entering the bladder
what is the function of the sphincter urethrae muscles?
controls urine expulsion
what is the function of bulbourethral (cowper’s) glands?
glycoprotein secretion in mucous during arousal
lubricates urethra/penis, controls acidity and removes dead cells
what is the function of the prostate?
produces enzymes to break down proteins, stop clotting and maintain semen in a fluid state
what are the 4 uterine positions?
anteverted and anteflexed
retroflexed
retroverted
retroverted and retroflexed
what ligaments hold the uterus in place?
round ligament - maintains forward orientation (anteflexus)
broad ligament - acts as a mesentery
what does the ovarian ligament connect?
ovary and lateral uterus
what does the suspensory ligament do?
contains blood supply to the ovarian artery/vein and connects to anterior abdominal wall
what is the rectouterine pouch?
a double fold of peritoneum between the rectum and the back wall of the uterus
what can occur if uterine tubes or the ampulla become blocked?
ectopic pregnancy
what can happen if water/electrolyte homeostasis isn’t maintained?
haemorrhage, dehydration, unusual eating/drinking behaviour
what is the typical water intake/output per day?
2.5 litres
what is the sequence of blood vessels in the kidneys?
afferent arteriole -> glomerular capillaries -> efferent arteriole -> tubular capillaries -> venule
name the 2 nephron types and state which one has more effective water reabsorption
superficial
juxtamedullary (more water reabsorption)
what are the 4 sections of the nephron?
PCT
LoH
DCT
collecting duct
what is nephron reabsorption?
the active pumping of filtrate into tubules in substances being retained (water/glucose)
what is nephron secretion?
the active pumping of filtrate into tubules for substances being eliminated (ammonia/uric acid)
what is ultrafiltration driven by?
BP in glomerular capillaries
what are the components of a glomerulus?
afferent/efferent arterioles
glomerular tuft
glomerular capillary
what composes the filtration barrier of the glomerular capillary?
podocyte foot processes
fenestrated endothelial cells
glomerular BM
slit diaphragm
what occurs in glomerulus ultrafiltration?
high glomerular capillary pressure (55mmHg)
water and small molecules filter through slits between podocytes at a normal filtration rate of 90-140ml/min
explain what occurs in proximal CT active reabsorption
in the brush border:
Na, K, AAs and glucose reabsorbed through co-transporters and membrame pumps
substantial water reabsorption and complete glucose/AA reabsorption
filtrate volume reduced by 2/3
what differences does the wall of the LoH have at different points?
thinner during descent into medulla
thicker during ascent from medulla
explain the counter current mechanism of the loop of henle
solute is actively pumped up ascending tube
solute diffuses into descending tube
this recycles the solute
what is the function and characteristics of the DCT?
function - solute absorption and secretion
less intense electrolyte/water reabsorption than PCT
ion pumping controlled by aldosterone (hormone that ‘fine tunes’ Na/K exchange)
what does AVP do?
decreases water loss by increasing uptake of water reabsorption in collective duct
how does ADH work?
promotes water reabsorption in DCT and collecting duct
what is the collecting duct permeability set by?
ADH and AVP
what occurs in collecting ducts permeable to water?
water moves out of the duct to concentrate filtrate
explain the function of aquaporins
they are inserted into luminal membrane to allow water movement when ADH or AVP is present
what is blood/plasma osmolarity?
a measure of the chemical components of the blood concentration
what is a normal value for blood osmolarity?
300 mOsm
what happens when water intake is restricted?
plasma osmolarity decreases
more ADH/AVP is secreted by the hypothalamus to reabsorb more water and concentrate urine
what is the maximum concentration of urine?
1200 mOsm
what is the minimum and maximum accepted urine output?
minimum - 1ml/min
maximum - 20ml/min
what is the second stage of filtration pressure and BP control in the kidney?
renin splits angiotensinogen into angiotensin 1 which is converted to angiotensin 2 (powerful vasoconstrictor)
what controls the salt balance in kidneys when electrolytes fall?
aldosterone
promotes reabsorption of Na/Cl ions and promotes K secretion
what signals volume in the bladder?
stretch receptors
what maintains bladder continence? (holding it in)
sphincter activity (can be unconcious or concious)
what measures bladder behaviour and compliance?
cystometrogram
what is the detrusor muscle affected by?
reflexes
wall stretching triggers contractions which produce additional force and pressure
what sphincter is present at the bottom of the urinary tract and how does it differ in M and F?
external sphincter
in males it is stronger with more skeletal muscle
what is notable about bladder pressure in the beginning of the storage phase?
no bladder sensations due to stretchy bladder walls, pressure remains fairly constant
what happens to the external sphincter when sensation is felt?
contraction
what is voiding?
the emptying of the bladder
what occurs straight after voluntary voiding?
bladder wall contracts
internal/external sphincters begin to relax
how can voiding be halted voluntarily?
contractions of both sphincters causing spike in bladder pressure
why does bladder pressure not immediately decrease during voiding?
to keep pushing the urine past the sphincters to empty the bladder
explain urine flow in terms of bladder and sphincter pressure
urine will flow out and void when bladder pressure exceeds sphincter pressure
what makes the coordination between the bladder and sphincters complex?
the external sphincter is skeletal muscle which changes force faster than the urethra (smooth muscle)
what sympathetic innervation does L1/L2 supply?
bladder and internal sphincter
what parasympathetic inervation does S2/3/4 supply?
bladder wall
what somatic innervations do S2/3/4 supply?
external sphincter
describe the afferent bladder control pathways
sensory fibres sense bladder wall stretching (through hypogastric nerve entering cord in upper lumar roots)
urethra sensors sense urine flow
skeletal muscle sensors sense external sphincter
describe the efferent bladder control pathways
parasympathetic to detrusor
sympathetic to internal sphincter
what causes contraction and relaxation of the detrusor?
contraction - pelvic splanchric nerve fibres
relaxation - hypogastric nerve fibres
what effects dominate the storage and voiding phases?
storage - sympathetic
voiding - parasympathetic
name the sensations accompanied with bladder filling in order
first fullness sense -> fullness -> desire to micturate -> discomfort -> pain
what nerve fibres provide sensation to the bladder?
large myleinated fibres - intense sensation
small unmyleinated fibres - less intense sensation
what is the general maximum bladder capacity?
400-600ml
what is the maximum micturition and detrusor pressure in the bladder?
micturition - 75-90cmH2O
detrusor - 55-75cmH2O
what are the 3 volume-pressure relationships?
normal - fills slowly to 375ml then reflex contractions start, then stop
neurogenic bladder - reflexes overactive and stiff bladder, higher pressures at lower volumes
atonic bladder - reflexes underactive and small
what is the problem of prostate hypertrophy?
urethra compression, slowing urine flow
what is the first stage of controlling filtration pressure and BP in kidneys?
hypofiltration initiates renin secretion by the juxtoglomerular apparatus
