B32 midterm summary .docx

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Biological Sciences
Kenneth Lam

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( the veins are where the input of blood is) , 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 AV 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 -then beta, G protein and then adnylyl cyclase( know how to spell them) !!! -rate of de is increased + frequency of AP increase( more frequent AP, faster HR) --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 so less frequency of AP --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 ,while in human heart, Ach is to decrease 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( aka the juxtamedullary cells: release renin ) -function of renin - renin secretion from baroreceptor from Juxtameddularry cells trigggered by which two factors ( medulla gada and macula densa ) what are the factors affecting ultrafiltratoin? -net hydrostatic pressure diffthats why when your body sense a drop in BP, or a decrase in GFR , renin will be released from juxtamedullary cells ( this is triggered by the the medulla obligada receptor, and the macula dnesa cells in the distal tubule) -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( recall that the ADH increase the water reabsorption by inserting more aquaprins into the distal tubule and collecting duct; while the antiogensin II act the AC to secrete aldesterone to increase the reabsoprtion of na+ into the interstitial fluid and hence water follows after -why?the increasing concentration in the interstitial fluid is maintained by the desceinding and ascending loop of Henleby actively pumping ions( active transport of NaCl into the interstitial fluid ) and passive diffusion of the NaCl into the interstitial fluid --in the upper portion, this pumping of ion is done by active transport of Nacl, and the lower you go, the more it pumps --in the lower por of the loop of Henle, this is done by passive diffusion of NaCl --after the interstitial fluid concentration is build up as you down the Loop of Henlel,you are also building up the increasing interstitial fluid concentration/osmolarity for the CT --you use CT to reabsorb water back to the blood, to maintain blood pressure --but the problem is when you go down the CT,almost at the bottom of the tubule, you want to give a push in the water reabsorption, by what ? by the passive diffusion of urea from the lumen into the intersitital fluid, which can contribute to the increasing osmolarity in the interstitial fuild ( counter-intuitive at first sight, since you want to get rid of the urea in the urine, but now you are reabsorbing it back to the blood ) 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 kidney 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+( H+ is secreted into the kidney lumen and as urine) -so H+ excretion into urine , and HCO3- reabsorption all the time -how? CO2( diffuse from the blood into the interstitia
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