A & P - Urinary System Flashcards
what does the urinary system consist of?
kidneys
bladder
ureter
urethra
what is the function of the bladder?
storing urine
what are the layers of the bladder?
serous
muscular
inner mucous coat
how much urine can the bladder hold?
250-300ml normally but up to 500ml
what is the function of the urethra?
to pass urine from bladder to exterior
how does the urethra differ in men and women?
women - shorter (4cm), only serves urinary system
men - longer (18-20cm), serve urinary and repro. systems
what is the function of the ureter?
to carry urine from kidney to bladder
what is the structure of the ureter?
25-30cm long, thick walled tube ~3mm thick
uses peristalsis contractions 4-5 times a min
what are the functions of the kidneys?
reg. body fluid / volume / osmolality maintains electrolyte balance formation of urine excretion of metabolic waste acid base balance production of hormones / enzymes activation of vit D
what is osmolality?
concentration of solutes in body fluid
what is the normal osmolality of the body?
280-300mOsm Kg
what % of the body is fluid?
70% (32-40l)
describe the distribution of fluid in the body
intracellular - 25l
interstitial - 11l
plasma - 3-5l
what is the functional part of the kidney called and what are they made of?
function part - parenchyma made of - cortex and renal pyramids
what di the renal pyramids consist of?
straight tubules
how many nephron does each parenchyma have?
~ 1 million
describe the path of blood flow through the kidney
renal artery interlobar arteries arcuate arteries interlobular arteries interlobular veins arculate veins interlobar veins renal veins
name two types of nephron
juxtamedullary nephron
cortical nephron
name 4 functions of the nephron
- glomerular filtration
- tubule reabsorption
- tubule secretion
- water conservation
what is the endothelial-capsular membrane?
3 layers that act as a filter - lets some material from blood pass and restricts others
what is the usual glomerulus filtration rate?
women - 115ml/min = 160l plasma p/day
men - 125ml/min = 180l plasma p /day
what is a usual daily urine output and what does it consist of?
1-2l per/day - most water and solutes reabsorbed
what is the standard measure of glomerulus filtration?
check creatinine
describe the structure and function of the proximal convoluted tubule (PCT)
long length and microvilli increase surface area
mitochondria - for active transport
reabsorbs chemicals
name 4 chemicals reabsorbed in the proximal convoluted tubule, by which method are they absorbed and how much
sodium - 65% (active transport)
glucose - 100% (secondary active transport)
amino acids - 100% (secondary active transport)
water - 65% (osmosis)
what happens when the transport proteins used in active transport are saturated?
glucose (>220mg/dl) remains in the urine (glycosuria)
what is reabsorbed in the loop of henle and in what amounts?
sodium 25% (AT)
water 25% (osmosis)
what is reabsorbed in the distal tubule and collecting duct and in what amounts?
sodium 8-10% (AT)
water 8-10% (osmosis)
what controls the sodium and water balance in the nephron? and what is its purpose?
hormones control sodium and water balance which regulates blood pressure
which hormones are involved in the regulation of sodium and water balance?
aldosterone
atrial natriuretic peptide (ANP)
anti-diuretic hormone (ADH)
what function does aldosterone serve?
stimulates sodium reabsorption
increases blood volume
what function does atrial natriuretic peptide (ANP) serve?
increase sodium excretion
decreases blood volume
what function does atrial anti-diuretic hormone (ADH)serve?
more - increases water reabsorption
less - decreases water reasborption
which part of the nephron do hormones work to control sodium and water balance?
distal tubule and collecting duct
what is blood pH?
measurement of concentration of H+
what is a usually blood pH?
atrial pH - 7.45
venous pH 7.35
(acceptable range 6.8-8.0)
what is acidosis and what are the symptoms?
pH be 7.35
depression of CNS, disorientation, coma
what is alkalosis and what are the symptoms?
pH above 7.45
convulsions, respiratory spasm
what are the metabolic causes of H+ in blood?
- carbonic acid formation
- catabolism of organic nutrients, meats, proteins (form sulphuric and phosphoric acid)
- organic acids from intermeditate metabolism of fatty acids during meat metabolism and lactic acid from excercise
how is acid base balance maintained?
- lungs
- proximal tubules (PCT) cells
- type A intercalated cells in collecting ducts
how do the proximal tubules (PCT) cells maintain acid base balance?
secrete H+ ions
reabsorb HCO3 ions
excrete ammonium ions
generate HCO3
how do the type A intercalated cells in collecting ducts maintain acid base balance?
secrete H+ ions
reabsorb HCO3 ions
excrete dihydrogen phosphate ions
generate HCO3
which hormones are secreted by the kidney and what are their roles?
renin - control total body fluids
erythropoietin - stimulates RBC production
what does the kidney activate?
vitamin D, needed for calcitriol which regulates calcium and phosphorus in blood
why is urine yellow?
urochrome from breakdown of haemoglobin
what gives urine its odour?
bacteria degrade urea to ammonia
what is the osmolality of urine?
50-1200 mOsm/kg
what is the pH range of urine?
4.5 - 8.2 (usually 6.0)
what is the chemical composition of urine?
95% water
~ 5% solutes (urea, NaCl, creatinine, uric acid)
what controls bladder function?
stretch receptors
sensory fibres
interneuron relays
parasympathetic motor fibres
what role do the interneuron relays play in bladder function?
sends sensation to thalamus, then cerebral cortex - makes you aware you want to wee
what role do the parasympathetic motor fibres play in bladder function?
relay impulses from pelvis to post-ganglionic neurons - stimulate detrusor muscle to contract, micturition occurs after voluntary relaxation of sphincter
what is the cause of kidney disease in diabetic patients?
damage to large and small renal blood vessels - leads to lack of blood supply to kidney and cell death
why can hypertension cause kidney failure?
nephron glomeruli damaged by high pressure so no longer filters blood
in both diabetes and hypertension the renal blood vessels become damaged, what effect does this have on the glomeruli?
glomeruli become ‘leaky’ allowing albumin to enter urine
name two congenital renal abnormalities
autosomal dominant polycystic kidney disease (ADPKD) - renal cysts
renal chloride diseases - barters syndrome, gitelmans syndrome, dents syndrome
what are kidney stones?
calcium compounds - oxalate or phoshate
what do the terms nephrolithiasis and urolithiasis mean?
nephrolithiasis - stones in kidneys
urolithiasis - stones anywhere in urinary system
what are the symptoms of kidney stones?
often none sharp back pain or in side, abdomen, groin nausea/vomiting haematuria (blood in urine) infection
what is glomerulonephritis and what causes it?
inflammation of kidney glomeruli - impaired filtering
causes - post infection complications, lupus
symptoms - blood/protein in urine
what is acute kidney failure and what are the causes?
sudden loss of renal function
causes - ureter or bladder obstruction, extreme low BP, toxic injury, blockage of renal blood supply
what is chronic kidney disease (CKD)?
gradual loss of renal function, marked by 5 stages
list the stages of chronic kidney disease and the glomeruli filtration rate at each stage
stage 1 - GFR >90ml/min stage2 - 60-89ml/min stage 3 - 30-59ml/min stage 4 - 15-29ml/min stage 5 - <15ml/min
what treatment is given for renal failure (end stage renal disease)?
dialysis or transplantation
what are the early symptoms of chronic kidney disease?
high BP
frequent urination
difficult/painful urination
swollen hands/feet
how is urinalysis used to detect kidney damage?
detects proteinuria (early marker)
detects abundant protein albumin
usually 30mg/day but in proteinuria 300mg/day
what risk factors are linked with chronic kidney disease?
obesity (itself and increase risk of diabetes/hypertension)
genetic factors
usually due to multiple risk factors
what treatments are available for chronic kidney disease?
control of blood pressure
weight control
dialysis
how can diet be used to control CKD?
reduces work of kidneys if the following are reduced:
protein (urea build up)
phosphorus (removes calcium)
sodium (reduce BP)
name the two types of dialysis which can be used in end stage CKD
haemodialysis
peritoneal dialysis
explain how a kidney transplant is performed
new kidney - lower abdo.
joined to iliac vein in leg
renal artery joined onto iliac artery
ureter joined to bladder
list three problems with kidney transplant
requires donor
risk of infection
immunosuppressive drugs - increase risk if cancer and infection
