Homeostasis Flashcards
What causes molecules to be forced through the glomerulus into the Bowman’s capsule?
the afferent arteriole being wider than the efferent arteriole; increases blood pressure
What might cause a lower glomerular filtration rate?
4 reasons
- kidney disease
- cancer
- dehydration
- low blood pressure/loss of blood
What is reabsorbed in in the proximal convuluted tubule?
water and glucose
What part of the loop of henle is permeable to ions?
ascending limb
What part of the loop of henle is permeable to water?
descending limb
What does ADH stand for?
anti-diuretic hormone
if ADH levels increase, what happens to urine output?
decrease
What is the effect of ADH on the collecting ducts permeability to water and why?
increases permeability because increase the number of aquaporins
if ADH levels are lowered, what happens to the aquaporins?
get broken down by lipsomes
What is present in the glomercular filtrate?
urea, water, glucose, inorganic ions, amino acids
Where is the loop of henle located?
medulla
Where is the proximal convuluted tubule located?
cortex
What supplies the kidney with blood?
the renal artery
Why does water move out of the descending limb?
due to concentration gradient between the descending limb and the interstitial fluid. there is a higher water potential inside the limb than outside, causes water to move out via osmosis
What connects the renal pelvis to the bladder?
ureter
What is negative feedback?
a process in which a change in some parameter brings about processes which return it back to normal/homeostasis
What is positive feedback?
a process in which a change in some parameter brings about processes that move its level further in the direction of the initial change
Define homeostasis.
the maintenance of a relatively constant internal environmental for the cells within the body
What is a set point?
ideal value of a pyhsiological factor that the body controls in homeostasis
Why is deaminiation useful?
because excess protein is not needed, and is not stored, but the energy from proteins should still be utilised
What happens in deamination?
-NH2 group (amine group) and H+ is removed from the amino acid, producing NH3 and a keto acid
What happens with the ammonia produced in deamination?
combines with carbon dioxide to produce urea and water
Why is important that ammonia is converted into urea?
because ammonia is damaging in high quantities; urea is less toxic and less soluble
What happens to the keto acid left after deamination?
- enter Kreb’s and be aerobically respired
- converted to glycogen/fat for storage
- converted to glucose
Where does deamination occur?
liver
What does a keto acid look like?
R
I
HOOC - C=O
What kind of blood does the renal artery carry?
oxygenated
What kind of blood does the renal vein carry?
Deoxygenated
What is present in the renal artery?
urea, glucose, inorganic ions, large proteins, blood cells, salts
What occurs across the glomerulus and the Bowman’s capsule?
ultrafiltration
Where does selective reabsorption occur?
PCT, loop of henle
What is the benefit of the pedicels on the podocyte cells of the Bowman’s capsule?
increase SA for increased filtration rate =? diffusion?
What is the function of the basement membrane?
- seperates the podocytes from the arteriole
- stops large proterins from getting through = filter
Why does the basement membrane have gaps?
allow fluid through -> liquid part of blood into the glomercular filtrate
What are the adaptations of the PCT?
4 points
- microvilli which increases SA for greater reabsorption
- one cell thick walls (thin) for short diffusion/active transport distance
- tight junctions to hold adjacent cells together to prevent leakage; fluid HAS to flow through cells and be filtered
- many mitochondria for active transport
