Osmoregulation Flashcards
Journey of blood to the glomerulus
Renal artery > afferent Arteriole > glomerulus capillaries inside the bowman’s capsule > (ultrafiltration) > leaves through efferent Arteriole
Glomerulus
Bowman’s capsule + glomerular capillaries
When blood enters the glomerular capillaries it is…
Under high hydrostatic pressure
Why is blood on the glomerular capillaries under high pressure?
Because the afferent Arteriole is wider than efferent Arteriole
Pressure build up between these points inside glomerular capillaries
What does high hydrostatic pressure in glomerular capillaries cause?
Force out fluid of capillaries containing glucose, water, NaCl, amino acids, ions from the blood
Into the Bowman’s capsule
Bowman’s capsule contains what after ultrafiltration?
The ‘glomerular filtrate’ = glucose, NaCl, water, amino acids, ions
Why are red blood cells not forced out of the capillary into bowman’s capsule?
Because pores in the capillary endothelium are too small so red blood cells do not allow RBCs out
Why are plasma proteins not forced out the glomerular capillaries into bowman’s capsule?
Because there is a basement membrane over the glomerular capillaries which is made up of proteins: a mesh with smaller pores to act as a ‘finer’ filter
Too small pores to force plasma proteins out
What remains in blood during ultrafiltration?
Red blood cells, plasma proteins
Can water re enter the blood in glomerular capillaries from the bowman’s capsule, following ultrafiltration?
No, water can only move OUT from blood into glomerular filtrate in bowman’s capsule due to the huge hydrostatic pressure build up
Why would water be able to re enter the blood in glomerular capillaries?
Because there is a large water potential gradient that would allow water to move by osmosis from bowman’s capsule into blood
Blood is highly concentrated with plasma proteins so low water potential
