respiratory 3

Question 1

human RBCs are unique, when they are mature and released in blood stream, they have no ___, so…, they have no ___, so…., they have no ____, soooo, and they have no ___, so they are this size

Answer 1

nucleus, so cannot divide once mature
ER, no protein synthesis-cannot grow or repair themselves
mitochondria, so energetically, they are limited to glycolysis
no other internal organelles, so they are not spherical b/c nothing to give them shape, so they are called biconclaved discs

Question 2

human RBCs have a ___ biological life span in the circulatory system

Answer 2

relatively short
at max, last 120 days and then rupture

Question 3

what is an important measurement of human RBCs? it is defined as the ___

Answer 3

hematocrit (HCT), defined as the fraction of total blood volume made up of the RBCs

Question 4

to measure hematocrit levels, fill capillary tube with blood and centrifuge, blood on bottom & plasma on top, the WBCs make a white band on top called ___, put tube on reader and it tells you the % that total volume is made of ___

Answer 4

buffy coat
RBCs

Question 5

hematocrit changes with different factors…

Answer 5

developmental life stages
certain diseases (polycythemia, cigs)
environmental factors- high altitudes

also a measure of athletic training and elite performance

Question 6

___ is a form of blood cancer in which RBCs that are made in the bone marrow have a mutation of a certain gene that results in…

Answer 6

polycythemia
overproduction of RBCs

Question 7

since RBCs have no internal organelles, what are the advantages of this?

Answer 7

1- all the room inside is available to pack as much hemoglobin in those cells as possible (250 million hemoglobins per RBC & each hemoglobin carries 4 oxygens –> supports the high metabolism in animals)

2- the RBC is very flexible, it can bend (advantage when RBC has to go through individual capillaries –> diameter of RBC is bigger than diameter of capillary, so RBC bends back on itself as it goes thru capillaries and in a single file, there is almost no distance b/w the wall of the capillary and the RBC, this decreases the diffusion distance oxygen has to travel to get from RBC to tissue its traveling to

Question 8

___ is the 3rd most abundant protein in the body

Answer 8

hemoglobin

Question 9

RBCs are synthesized in the ___ in process called ___

Answer 9

bone marrow
erythropoiesis

Question 10

erythropoiesis is under hormonal control by ___, which is synthesized in response to ____

Answer 10

erythropoietin (Epo)
low oxygen and aerobic exercise (athletic training)

Question 11

when the maturing RBC exits bone marrow and goes into blood stream, it has to go through ___, it gets deformed and ___ gets pushed out of cell

Answer 11

sinusoid bone marrow
nucleus

Question 12

erythropoiesis is under control of the hormone Epo, this has some downstream effects…

Answer 12

• cancer patients undergoing chemo, which target rapidly dividing cells, end up targeting hair cells and RBCs –> patients become anemic, they are given Epo in order to maintain normal levels of RBCs

–> athletes realized this could be a powerful tool to give them endurance (used Epo to increase aerobic capacity, especially competitive cyclists), however, bad consequence, blood gets thicker and heart has to work harder and harder for RBC to get thru capillary –> died from strokes

Question 13

CO2 is __x more/less water soluble than oxygen

Answer 13

28x more

Question 14

CO2 is transported very differently than oxygen b/c it has diff properties, even tho CO2 is a nonpolar gas, it is not as nonpolar as oxygen, so it is not as ___

Answer 14

water insoluble, 28x more water soluble

Question 15

blood can hold 28x more CO2 dissolved in ____…

Co2 reacts with….

Answer 15

water environment
CO2 reacts with water to form carbonic acid –> dissociated into bicarbonate and protons

Co2 can exist in blood in 3 diff chemical forms/species: molecular CO2, carbonic acid, or carbonic ion

Question 16

CO2 reacts with water slowly…

Answer 16

enzyme called carbonic anhydrase speeds it up (one of fastest enzymes known), 1 molecule of carbonic anhydrase can convert 1 million molecules per second

Question 17

what does equilibrium of the CO2 –> bicarbonate rxn depend on

Answer 17

pH of the blood

molecular CO2 is 5% of total, bicarbonate is 95%, carbonic acid is 1/100%

Question 18

___ is the most abundant form of CO2 in the blood

Answer 18

bicarbonate

Question 19

CO2 enters blood as this form of CO2, ___, and exits blood through the lung as this form, __

Answer 19

molecular CO2
molecular CO2

Question 20

CO2 moves thru body: CO2 diffuses into blood –> once in blood, some can simply exist as dissolved CO2, can also combine with water to form ___ (accounts for very little), whatever bicarbonate exists stays in the ___; most CO2 dissolves into ___ (can bind directly to ___ and forms ___, which alters ____…); CO2 combines chemically with water with enzyme carbonic anhydrase to form ___ and ___ very rapidly –> protons produced bind ___ and result in ___ to give up oxygen to tissues

Answer 20

carbonic acid
plasma
RBCs
oxyhaemoglobin
carbaminohemoglobin
alters oxygen affinity, facilitates the off-loading of oxygen from hemoglobin and delivery to tissues

bicarbonate & protons
oxyhaemoglobin, Borh shift

Question 21

as CO2 moves thru circulation, at end, have to get rid of bicarbonate by a transport protein in RBC membrane called ____…

Answer 21

chloride bicarbonate exchange protein (band 3 anion exchange protein)

binds bicarbonate on inside of membrane and binds chloride on outside –> transports chloride in and bicarbonate out, process called chloride shift

Question 22

as CO2 is expelled frm body and processes go in reverse, without carbonic anhydrase, what would happen?

Answer 22

conversion of bicarbonate back to CO2 is really slow