Week 10- Renal System Flashcards
What is the glomerular filtration rate determined on
Filtration rate
What does filtration rate need to be
Constant
What happens if the filtration rate is too fast
Filtration wont be reabsorbed
What happens if the filtration rate is too slow
Everything is reabsorbed
What drives fluid out
Hydrostatic pressure
Effect of proteins in arterioles
Has osmotic pressure in blood to oppose movement of fluid out as does hydrostatic pressure of filtrate
What regulates filtration
Arterioles size
Describe the juxtaglobular complex
The wall of distil convoluted tubule connects with afferent arterioles. When flood flows too quickly through the DCT the MACULA DENSA releases ATP which causes the afferent arteriole to constrict
Describe the process of reabsoprtion
Sodium potassium pump used to remove sodium from basal region
Sodium used to co transport other useful substances such as glucose
Peritubular hydrostsatic pressure s low and osmotic pressure is high so water (osmosis) and other ions move out the proximal convoluted tubule
What increases glomerular filtration rate
What wil this cause
Increases resistance of efferent arterole (constriction)
Increased pH in GFR
What decreases glomerular filtration rate
What will this cause
INCREASES RESISTANCE IN AFFERENT ARTEROLE (constriction)
Decrease capillary BP, decrease in pH
What does the wall of sitar convoluted tubule connect to
Afferent arterole
Describe juxtaglomerular process
The wall of distal convoluted tubule connects with afferent arterioles. When fluid flows too quickly through DCT, the MACULA DENSA releases ATP which amuses afferent arterole to constrict
What causes afferent arterole to constrict
JUXTAGLOMERULAR PROCESS
The wall of distal convoluted tubule connects with afferent arterioles. When fluid flows too quickly through DCT, the MACULA DENSA releases ATP which amuses afferent arterole to constrict
How many times is plasma filtered a day
60
What cell help with re absorption
Microvilli
Increase SA:V
Define blood pressure
The force applied to a unit area of surface of blood vessel wall by the blood contained within it
Which arterole is first
Afferent
Where does selective reabsorptoion occur
Proximal convoluted tubule
Substances are more likely to pass from the glomerulus into the proximal a convoluted tubule if they are ?s
Small and under high pressure
What is the glomerulus filtration rate
Flow of plasma from glomerulus into bowman’s capsule
What makes up the juxtaglomerular complex
Macula DENSA cells In loop of Henley and granular cells of afferent arterole of glomerulus
What do macula densa cells do
When the flow of filtrate is high it releases ATP into afferent arterole ofglomerulus causing it to contract
Where does reabsorption mainkhy occur
Proximal convoluted tubule
How are glucose molecules reabsorbed
Combination of active and passive transport across tubule cells
Why can hyperglycaemia in diabetes melitus cause glucose to enter urine
Excessive glucose in filtrate saturates the glucose co-transported
What makes the tubule cells impermeable
Lots of tight junctions and water
When does the hypothalamus shrink
When osmoreceptors detect when blood is concentrated
Or a drop in bpdetetced
What do osmoreceptors release when conc blood is detected
What does this do
ANTIDIURETIC HORMONE(ADH) / VASOPRESSIN
This circulates kidney and can cause behavioural change- thirst
Once ADH is released, what does it do? What does this cause?
Binds to its receptor in the DST and collecting ducts
Causes a release in AQUAPORINS
AQUAPORINS become membrane bound and allow the passage of water acros the cells and into capillaries by osmosis
By the time filtrate reaches DCT, how much water and sodium remains
Water- 25%
Na- 10%
Function of adrenal cortex of adrenal glands
Monitor sodium and potassium (electrolytes)
HIGH K+ or LOW Na+ stimulate release of the hormone ALDOSTERONE
Function of ALDOSTERONE
Stimulate DCT and collecting ducts
Increase rate of sodium potassium pump, increased rate of sodium uptake and potassium excretion
Cause production of more channels and pumps in longer term
What affects bp
Vessel diameter
Vessel length
Blood viscosity
Function of granular cells
Sensitive to BP in arterioles, release an enzyme called RENIN
STIMULATED BY THE CV CENTRE is sympathetic nerves and macula densa if flow is too slow
How is water reabsorbed in DCT
ADH stimulates release o9f AQUAPORINS
How would an increase in ADH change urine production and blood pressure
Decrease urine production
Increase blood pressure
Where is aldosterone produced
Adrenal cortex
What effect has aldosterone on kidney
Reabsorption if sodium ions
Excretion of potassium ions
What is rennin and where is it released from
Enzyme
Released from granular cells of JGC
What does renin do
Concert angiotensinogen to angiotensin 1
What affect does angiotensin 11 have
Increases cardiac output
Stimulates the release of ADH
stimulates release of aldosterone
Stimulates vasoconstriction
