Class Notes (1,100,000)
CA (630,000)
UTSC (30,000)
BIOB32H3 (100)
Lecture

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Department
Biological Sciences
Course Code
BIOB32H3
Professor
Kenneth Lam

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B32
LEc 6
what's the meaning of 60Hz
Nernst equation for one single ion
Goldman equation for multiple ion ( na= and K+_ )
lec 5
bulk flow =convective transport
the sequence for blood flow in bony fish heart
--sinus venous, and then atrium, and then ventricle, and then bulbus arteriousu
where the pacemaker located for the fish and vertebrate animals?
-sinous venous
-sinoatrail node
what are the two types of conduction fibres
internodal pathway and purkinje fibres
sequece of AP conduction : first internal pathway, then AC node, then AV bundle
(bundle of his) then purkinje fibres
what are the method to upregulate and downregulate the heart rate?--by intervention
from nerves
-note that it's not direcly acting upon changing the movement of ions, but by acting on
the mscarinic receptor or the G protein, which then control the movement of the ion
through the ion channels, --so they( the receptors receiving the NT) are not ionic
channels
--sympathetic regulatoin
-neuron secrete NE, or neurone ask the adrenal medulla to secrete E

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-then beta, G protein and then adnylyl cyclase( know how to spell them) !!!
-rate of de is increased + frequency of AP increse
--para: to decrease HR
-para neuron secrete Ach
-muscarinic receptor ( not direcly control the movement of ion, so similar to beta
receipr and G protein )
-wich then act on G protein
-which act on the K+ and Ca++ channels
--what kind of effect may b seen here?
-to resist the further depolarization
--slowing the slope
==time for depolarization is longer
==increasing the distance between the potentials
--increase time for depolarization
-decrease frequency of AP
-so both involve the Ca2+ channel
but in anthropoid heart, which is neurogenic
--you see the Ach to increase HR
if i give you bath two types of heart ( my heart and antropod heart) into Ach-bathed solution,
then you expec tto see opposite heart rate change
lec 4
the bird 's air sac's function
--to disassociate the movement in the mouth and trachea ( deadspace) with the foliation of
the lungs, so that the lungs can still do gas exchange without fresh air getting into the bronchi
birds and fish do counter-current in respiration --in parabronchin
huma do concurrent respiration -in alveolar and bronchi
macula densa : distal tubule
granular cells: release renin
-function of renin -™
what are the factors affecting ultrafiltratoin?
-net hydrostatic pressure diff
-colloid osmotic pressure of blood( attraction by protein in the blood)
-hydraulic permeability along capillary
urine formation
1 as you go down the luman, you see increasing conc in the interstitial fluid
-for what?--to make sure water is reabsorbing by osmosis from the lumen into the
interstitial fluid
-why?-- by pumping ions and urea out of the lumen
--in the upper portion, this pumping of ion is done by active transport of Nacl, and
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the lower you go, the more it pumps
--in the lower port, in the CT, this is done by passive diffusion of urea ( counter-
intuitive at first sight, since you want to get rid of the urea in the urine )
2
renal corpuscle, ( B and gloomier) : ultrafiltrate the glucose and AA from blood into the lumen ,
but most (100%)of which is reabsorbed back in the next step
prox. tubule: site of glucose and AA reabsorption
dist, and CT: filtrate K+, H+ and NH3(buffer) into lumen --that's why human and birds have
slightly acidic urine
: reabsorb Na+ and Cl- and HCO3- into interstitial fluid and then to the blood ,
but Cl- wll stay inside the interstitial fluid
glucose reabsorption -3 method
your blood have mostly HCO3-, and almost no H+
-so H+ excretion into urine , and HCO3- reabsorption all the time
-how?
CO2( diffuse from the blood into the interstitial fluid) 's CA reaction to make H+and HCO3-
--slide to pump H+ into lumen, and HCO3 reabsorb back to blood
how to make sure H+ keeps going into the lumen, even when there's lots of H+ already in the
lumen? --note that H+ pump stops when urine pH is lower than 4.5, so how does it keeps on
pumping h+ into the lumen?
-by buffering chemical: ammonia ( NH3) from the blood by diffusion, or phosphate
( HPO42-) by filtration in the Renal corpuscle
-ammonia is a breakdown product of protein, so if you eat lots of protein, then you'll
have acidic urine
-cause too much buffer ( NH3) in the blood from SI, and then in the lumen
how does renin -angiotensin system work , and how does anti-diuretic hormone work?
what happens when your BP is dropping /when you are loosing water?
-increased renin, and all the downstream enzymes( antiogensin I, II), aldosterone from
AC( in charge of Na+ reabsorption), and increase ADH ( in charge of H20 reabsorption by
permeability control) in CT
ADH=vassopression =anti-diuretic hormone ( reserve water, instead of pee it out)
-the two signals to stimulate its secretion
--low BP and high plasma osmolarity
--the reverse of which are to inhibit
-how does it increase the water reabsorption?
--by increase the amount of aquaporin --process!!!!
vasopression to G receptor, then AC, then cAMP from ATP , then protein
kinase A( PKA), then Pi of vesicles, and then translocation of vesicles to insert their aquaporin
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