W9 Renal Physiology Flashcards
Where are the kidneys located
one on either side of the spine located in the posterior wall of the abdominal cavity just below the rib cage
why is the right kidney slightly lower than the left because of the position of the liver
due to the position of the liver
what is the average weight of an adult human kidney
120 - 140g
what flows in the renal artery
nutrients such as
- Na+
- K
- Amino acids
- Glucose
Oxygen
Waste such as
- Urea
what is the vasa recta
the capillary networks that supply blood to the medulla
what are peritubular capillaries
tiny blood vessels in your kidneys. They deliver wastes to be secreted into urine (pee). They also reabsorb nutrients your body needs. Peritubular capillaries play an essential role in your urinary system.
how much of the cardiac output do the kidneys recieve
25%
how much plasma on average do the kidneys filter in a 70kg human
120 litres
Label a kidney
slide 1
what are the three main parts of the nephron
renal corpuscle
renal tobule
capillary network
label a nephron
label a nephron
where do the peritubular capillaries surround
they surround the proximal and distal convoluted tubules
what does the vasa recta surround
the loop of henle
what are the three main processes that take place in the nephron
ultra filtration
reabsorption
secretion
Where does ultra filtration take place
occurs in the glomerulus & bowmans capsule
how does ultra filtration take place
blood enters the glomerulus under a high pressure due to the size difference in the lumen of afferent and efferent arteriole at either end of the glomerulus
the constituents from the blood leave the glomerulus and enter the nephron which forms the filtrate.
what is filtration dependent on
filtration is determined on the size of the molecule for example small molecules such as water and have a molecular mass of up to 5000 flow freely however larger molecules such as albumin with 69,000 mw are less likely to move across
what is reabsorption
movement of constituents from the tubular fluid back into the blood to stop the constituents from being excreted.
what is reabsorption aided by
vasa recta + peritubular capillaries
what is transcellular and paracellular mean
Transcellular transport involves the transportation of solutes by a cell through a cell
Paracellular transport refers to the transfer of substances across an epithelium by passing through the intercellular space between the cells.
in what form of transport does reabsorption rely on
both paracellular + transcellular
what is secretion
movement of constituents from the blood into the tubular fluid so that they are excreted in the urine
what is the easiest way to remember the difference between secretion and reabsorption
reabsorption is removing stuff from final product of urine
secretion adds to final product of the urine
what form of transport does secretion rely upon
both paracellular + transcellular
what are the 4 main roles of the kidney
homeostasis
produce an active form of vitamin D that promotes strong and healthy bones
control the production of red blood cells
remove drugs from the body
how is the kidney involved in homeostasis
removing waste products from the body
regulating the pH of your blood and blood pressure by regulating inorganic ions
regulating water balance to maintain osmolality
releasing hormones that influence water balance and regulate blood pressure
what is the main component of urine
urea
what is contained in the urine
urea
uric acid
creatinine
what is completely reabsorbed by the body
protein and glucose
how much Na+ is reabsorbed
60-70%
how much HCO3- is reabsorbed
90%
where is Na+ and HCO3- reabsorbed
proximal convoluted tubule
is the descending limb of the loop of henle impermeable to ions
yes
what does the ascending limb contain
Na/K pumps
Na/K/Cl transporters
what does the containment of pumps and transporters in the asscending limb mean
Na, Cl and K ions leave the tubular fluid via the vasa recta
where does the reabsorption of water take place
tubules of the nephrons
what are the two ways in which we can reabsorb water
along an osmotic gradient (passive)
by the release of hormones from the kidneys (active)
what is the general relationship with sodium and water
wherever sodium goes water follows
where is the majority of the water absorbed
proximal convoluted tubule as this is where 60-70% of the sodium is reabsorbed
what hormones does the kidney release to regulate blood pressure
anti diuretic hormone
it is also involved in the renin angiotensin aldosterone system
what cell is involved in the release of renin
juxtaglomerular cells
when do they release renin
when we have a low blood pressure
sympathetic nerves
low sodium levels picked up by the mascular densa cells
what are the mascular densa cells
Macula densa (MD) cells are chief cells within the kidney, playing key sensory and regulatory functions in the maintenance of body fluid, electrolyte homeostasis, and blood pressure.
what is a chief cell
chief cells (zymogenic) are basophilic cells that are located in the bottom of the gland and which produce different gastric enzyme precursors
describe the affects of rennin
liver produces angiotensinogen which is inactive
renin combines with this to produce angiotensin 1
endothelial cells produce angiotensin converting enzyme (ACE)
ACE combines with angiotensin 1 to produce angiotensin 2
what does angiotensin 2 target
smooth muscle cells causing increased resistance in the form of vasoconstriction increasing blood pressure
kidneys as it signal them to reabsorb more Na+ and therefor more water
pituatary gland signaling for the release of anti diuretic hormone (ADH)
Adrenal gland signalling to release aldosterone
where is ADH released from
pituitary gland
what is the goal of ADH
reabsorption of water
what is release of ADH triggered by
angiotensin 2 (Renin angiotensin aldesterone system)
osmoreceptors if there is a higher concentration of blood
low blood volume: the sympathetic nerve ending in the veins of the heart will sense this
low blood pressure: sympathetic nerve endings in the arteries of the heart will sense this
what is a condition that can cause ADH to not work correctly
diabetes insipidus
- kidneys are unable to conserve water making pale watery urine at an increased rate of urination (15-20 mins) increased thirst, always feeling dry
what are the two types of diabetes insipidus
cranial diabetes insipidus
nephrogenic diabetes isnipidus
what can cause cranial diabetes insipidus
brain trauma damaging hypothalamus or pituitary gland
severe head injury damaging hypothalamus or pituitary gland
complications that occur during brain or pituitary gland surgery
what are the causes of nephrogenic diabetes insipidus
nephrons unable to respond to ADH
genetic
acquire from use of longterm lithium for bipolar disease or other causes such as hypercalcaemia or obstruction of the ureters
