[16.5] control of blood water potential - structure of nephron Flashcards
what is osmoregulation?
the homeostatic control of the water potential of the blood
what does blood plasma contain? (6)
- water
- urea
- glucose
- ions (Na, Cl etc.)
- plasma proteins
- amino acids
where does urea come from?
- nitrogenous waste
- we can’t store excess AA in the basic structure form
- you can use one AA to make another by changing the R groups
how does deamination occur?
- remove the R group
- slice NH₃ / COOH
- COOH can be used as a respiratory substrate
- ammonia (NH₃) is the main toxic waste product
what is NH₃ converted into?
- NH₃ is too toxic
- converted into urea
- urea is not toxic enough that it can go through liver to kidneys etc.
- ammonia + carbon dioxide -> urea
what are the different components of the kidney? (7)
- fibrous capsule
- cortex
- medulla
- renal pelvis
- ureter
- renal artery
- renal vein
what is the fibrous capsule?
outer membrane that protects the kidney
what is the cortex?
- lighter coloured outer region
- made up of renal (bowman’s) capsules, convoluted tubules and blood vessels
what is the medulla?
- darker coloured inner region
- made up of loops of henle, collecting ducts and blood vessels
what is the renal pelvis?
funnel-shaped cavity that collects urine into the ureter
what is the ureter?
tube that carries urine to the bladder
what does the renal artery do?
supplies oxygenated blood to kidney from the heart via the aorta
what does the renal vein do?
- removes blood from kidney
- returns deoxygenated blood to the heart via the vena cava
how do renal arteries and veins differ?
different compositions ie. concentrations of substances in the blood plasma
what is a nephron?
functional unit of the kidney
what are the different components of a nephron? (5)
- renal (bowman’s) capsule
- proximal convoluted tubule (PCT)
- loop of henle
- distal convoluted tubule
- collecting duct
what are podocytes?
specialised cells making up the inner layer of bowman’s capsule
describe the proximal convoluted tubule
- series of loops surrounded by blood capillaries
- walls made of epithelial cells which have microvilli
describe the loop of henle
- loop that extends from the cortex into the medulla of the kidney and back again
- has descending limb and ascending limb
- surrounded by blood capillaries
describe the distal convoluted tubule
- series of loops surrounded by blood capillaries
- surrounded by fewer capillaries than PCT
- walls are made of epithelial cells
describe the collecting duct
- where many DCTs from many nephrons empty
- lined by epithelian cells
- becomes increasingly wide as it empties into the pelvis of the kidney
what are the blood vessels associated with each nephron? (4)
- afferent arteriole
- glomerulus
- efferent arteriole
- blood capillaries
describe the afferent arteriole
- arises from renal artery
- supplies nephron with blood
- afferent arteriole enters bowman’s capsule where it forms the glomerulus
describe the glomerulus
- mass of blood capillaries in bowman’s capsule
- where fluid is forced out of the blood
- glomerular capillaries recombine to form the efferent arteriole
