Kidney Flashcards
who has a longer urethra
males
role of the urethra
females: urination
males: reproduction and urination
location
either side of the VC, on the post abdominal wall
behind the peritoneum, below the diaphragm
T12 and L3
lies obliquely upper pole 2.5cm closest to the spine and lower poles 7.5cm away from the kidney
right kidney lies slightly lover due to the liver
left kidney relations
sup: left adrenal gland
ant: spleen, stomach, pancreas and jejunum, splenic flexure of colon
post: diaphragm, post abdominal wall
right kidney relations
sup: right adrenal gland
ant: right liver lobe, duodenum, hepatic flexure of colon
post: diaphragm, post abdominal wall
renal capsule
inner most layer
made of collagen fibres, maintains shape and aids protection
adipose capsule
surrounds the kidney
fat people have a thicker layer
helps attach the kidney posteriorly to the abdominal wall, protecting the kidney
renal fascia
composed of dense connective tissue, final attachment of the kidney to the abdominal wall
encloses the kidney and the renal fat
renal cortex
lies next to the capsule
reddish in colour, granular appearance
renal medulla
inner most layer found deep in the cortex, consists of 6-18 renal pyramids due to the CD in the nephron
renal cortex + medulla =
renal parenchyma
(functional part)
how many nephrons inside the kidney
1-2 million
where does CD transport urine
from the pyramids to the calyces
what are the CD supported by
connective tissue containing blood vessels, nerves and lymph vessels = diffusion of nutrients and waste
what does the nephron consist of
PCT, LoH, CD, DCT and glomerulus
what is the nephron
a tubule which is closed at one end that joins a CD at the other end
the closed end is indented to form a glomerular capsule, which almost encloses a network of capillaries
the CD unites forming larger ducts which empty into minor calyces
where does the renal artery enter
hilum
what happens to the renal artery
it divides into smaller arteries and arterioles, the afferent arteriole enters the casks and subdivides into smaller artery capillaries forming the glomerulus
what are the capillary loops
made up of connective tissue, phagocytic mesogial cells which are part of the monocyte macrophage system
describe the difference in arteriole in the glomerulus
the afferent is larger in diameter increasing the hydrostatic pressure, this then drives the filtration across the capillary walls
maintaining oxygen and nutrient and removes waste
efferent arteriole subdivides into the peritubular network allowing for the exchange of fluid and blood
what happens to the venous drainage at the glomerulus
leaves the kidney at the renal vein into the IVC
glomerulus and GC composed of
composed of single layer of flattened epithelium
what are renal blood vessels supplied by
sympathetic and parasympathetic
controls diameter and blood flow independent of auto-regulation
what is the hilum
entry and exit point for blood and lymph vessels, and ureters
what are the calyx walls and pelvis wall composed of
transitional epithelium with smooth muscle
peristalsis forces prune through the calyces renal pelvis and ureters into the bladder
where is urine stored
renal pelvis
describe the renal pyramids and calyces
minor calyx sits below the pyramid which collects urine from the CD
several minor mere into a major
with 2 or 3 major forming a renal pelvis, which narrow in shape as it leaves as the ureter
renal columns separate the pyramids
renal papillae is the pointed part of the pyramid as the nephron empties urine it goes into these structures
where does urine go
through the renal papilla at the pyramid apex into a minor calyx
how much cardiac output does a kidney recieve
1/4 or 20%
what renal artery is shorter
left
the aorta lies left of the midline
what renal vein is shorter
right
IVC sits on the RHS
what does the aorta give rise to
right and left renal arteries
renal veins merge into the hilum
what is nephritis
inflamed kidney
what is the flow in lymphatics
follow the route of the renal vessels
renal hilar nodes -> para aortic nodes
blood supply
AA -> L& R renal arteries -> afferent arteriole -> glomerulus -> efferent arteriole -> L&R renal veins -> IVC
what do the ureters do
carry urine from the kidney to the urinary bladder
continuous with the renal pelvis, passes downed through the abdominal cavity behind the peritoneum and infront of the PSOAS muscle into the pelvic cavity
passes obliquely through the posterior wall of the bladder
what happens as urine builds up
pressure increases, compressing the ureters and openings into the bladder are occluded, prevents back flow
structure of the ureters
outer layer = fibrous tissue, continuous with the fibrous covering
middle muscle layer = smooth muscle fibres interlaced, additional longitudinal layer in the lower third
inner mucosa = transitional epithelium
function of the ureters
smooth muscle creates peristalsis which propels urine along
these increase in frequency with the amount of urine produced
what does low GFR impact
amount of water reabsorbed, accumulating waste
chronic kidney failure
gradual loss of kidney function/ nephron activity
loss of nephrons = low GFR
causing high levels of blood, urea and nitrogen
causes: diabetes mellitus, glomerular nephritis and hypertension
what is stage 1 of CKF
nephron loss is compensated for by the present nephrons, which become enlarged
75% can be compensated for
impact is only visible at stage 2
stage 2 of CKF
renal insufficiency, no longer able to adore to keep BUN levels stable
what is BUN
blood, urea, nitrogen
stage 3 of CKF
uraemia (high urea) sharp increase causes death
CANT BE REVERSED ONLY MANAGED
why does end renal failure occur
ph imbalance
function is lost
endocrine function is disrupted
final stages cause
itching, vomiting, muscle twitching, seizures, drowsiness, coma
kidney functions
urine formation
electrolyte balance
production and secretion of erythropoietin
water regulation
ph balance
maintenance of blood pressure
juxtaglomerular apparatus
exocrine structure which produces renin, erthropeotin, regulating BP, Hb and volume
assists in the regulation of GFR
close to the afferent arteriole
urine is composed of
water
ammonia, Na, K, Cl, phosphates, sulphates, oxalates
urea
uric acid
what gives urine its colour
urobilin
what reflects urines composition
exchange of substances, between the nephron and the blood in the renal capillaries
waste products of protein metabolism are excreted
water and electrolytes are reabsorbed through the excretion of H +
what are the three processes within urine formation
filtration
selective reabsorption
tubular secretion
glomerular filtration
occurs in the renal corpuscle (glomerulus and the BC)
the walls are porus which allows small molecules to pass through whilst plasma proteins remain in the capillaries. filtrate is high in solutes
filtrate has a similar composition to plasma apart fromthe plasma proteins and blood cells
filtration occurs due to the hydrostatic pressure difference, as the efferent is narrower it builds up the hydrostatic pressure
structure of the capsule
blind ended podocytes hug the capsule, with the gaps allowing the filtrate through
single layer of flattened epithelium
is filtration passive or active
passive process, which follows a negative pressure difference gradient
GFR
volume of filtrate formed/ min
tells us how quickly the kidneys can process chemo
can be calculated by injecting a RS monitoring at regular intervals
what is filtration controlled by
- renal auto regulation
maintain GFR at a constant pressure
operates independently to the NS, stimulated by pressure changes or fluctuating levels of metabolites
diameter alters itself at the afferent (decrease blood flow = small diameter). If BP is too low auto regulation will stop - neural regulation - stimulation of fibres causes vasoconstriction, reducing flow, less blood will decrease urine formation
blood is directed to other regions of the body
where does selective reabsorption occur
PCT
describe the structure of the PCT and LoH
PCT = cuboidal cells and microvilli
LoH = after the descending limb it becomes squamous epithelium
what are reabsorbed at the LoH
sodium so the filtrate at the CD is dilute
Na and Cl can be transported actively and passively
where does most water reabsorption occur
CD
what’s the transport maximum
maximum capacity for reabsorption of a substance
it takes into account the number of pumps
hormones which influence SR
parathyroid
aldosterone
ADH
ANP
parathyroid
secreted by the parathyroid gland
calcitonin regulates reabsorption of calcium and phosphate from the distal CD
parathyroid increases Ca
calcitonin decreases calcium levels
ADH
secreted by the posterior pituitary gland, which increases permeability in the DCT and CD
aldosterone
secreted by the adrenal cortex, which increases the reabsorption of Na and water, and excretion of K
ANP
atrial natriuretic petide
secreted by the atria in response to stretching of the atrium, when the volume increase, reabsorption decrease of Na and water from the PCT and CD
tubular secretion
mainly in the DCT
actively removes substances
cuboidal epithelium, lack of microvilli
secretion of H+ ions maintains normal blood pH
water balance
osmoreceptors in the hypothalamus detect changes in the OP in blood, which causes the release of ADH
when OP is high, ADH increases reabsorption in the CD and DCT increases, OP decreases
when BV increases, ANP is released which lowers reabsorption of sodium and water in the CD and PT so more is excreted, low blood volume and reduced atrial stretching
high levels of ANP inhibits aldosterone and ADH
what is electrolyte conc dependent on
water levels and electrolyte levels
what is the most common extracellular cation
sodium
what is the most common intracellular cation
potassium
what does the renin-aldosterone system do for sodium and potassium
maintains the levels
what juice is high is sodium
gastric
what juice is high in potassium
pancreatic and intestinal
renin-angiotensin-aldostrone system
aldosterone regulates sodium excretion, secrete by the adrenal cortex
cells in the afferent arteriole secrete renin in response to sympathetic stimulation, low BP or low BV
renin converts angiotensinogen to angiotensin 1
angiotensin converting enzymes converts angiotensin 1 to angiotensin 2 which is a vasoconstrictor increasing BP
renin and high potassium stimulates the adrenal gland to secrete aldosterone
reabsoprtion of water and sodium increases BV which reduces renin secretion
sodium reabsorption is high, potassium excretion is high reducing intracellular potassium
pH balance
PCT secrete H+ into the filtrate, combines with buffers
H+ + HCO3 = H2CO3 (carbonic acid)
H+ + NH3 = NH4+
H+ + HPO3 + H2PO3
carbonic acid dissociates into carbon dioxide and water
carbon dioxide is reabsorbed maintaining the buffering system
acute renal failure
sudden loss in function especially GF
can’t remove waste, can’t produce urine
obstruction
reduced renal flow (pre renal)
renal: damage to kidney
post renal: obstruction to outflow of urine
reduction in GFR and kidney function
oliguria and anuria accompanied by acidosis due to H+ retention, electrolyte balance and accumulation of nitrogenous waste
signs and symptoms
dysuria - oliguria (reduced urine), anuria (no urine)
polyuria - large volumes of dilute urine
anaemia - reduced RBC shortness in breath, fatigue, dyspnoea, cardiac failure
high in creatinine
over hydration: water retention, decrease in appetite, confusion
acidosis: high urea therefore high potassium, pH and H+
