heart, hormone, immuno

Question 1

cardiac output formula

Answer 1

CO = SV x HR

Question 2

how to increase CO?

Answer 2

Increase heart rate
increase contractile strength of muscle
Frank-Starling law: increase ‘stretch’ of heart muscle by increasing amount of venous return

Question 3

how to increase venous return?

Answer 3

increase total blood volume (this is done by retaining water in nephrons)
and contraction of large veins can increase venous return too

Question 4

order of events in cardiac action potential

Answer 4

Depolarization when fast sodium channels open
Slight dip when Na closes and K channels open, causing k to leave
Plateau maintained by slow calcium channels opening
Repolarization when Ca channels close
RMP when K channels finally close and the ATPase gets to work.

Question 5

action potential of the SA node (this is the pacemaker, not the AV node)

Answer 5

Self-depolarization: slow influx of NA through leak channels
Depolarization: Ca rushes in when voltage gated channels open
Repolarization: K rushes out when voltage gated channels open

Question 6

where do APs travel in heart?

Answer 6

SA node > atria depolarize and contract > travel down INTERNODAL TRACT > AV node (where it is delayed) > AV bundle (bundle of His) > R and L bundle branches > Purkinje fibers (only now do ventricles contract)

Question 7

autonomic reg of HR

Answer 7

vagus nerve synapse near the SA node and release ACh. This provides a constant level of inhibition called VAGAL TONE
As for symp, there are sympathetic neurons dropping NE directly on heart. Also, epinephrine from adrenal medulla binds to receptors on muscle cells
Lastly, there are BARORECEPTORS in carotid arteries and aortic arch that measure bp and hence adjust HR

Question 8

blood pressure

Answer 8

directly proportional to CO and peripheral resistance.

Question 9

local autoregulation

Answer 9

blood flow control on a local level. Certain metabolic wastes cause arteriolar smooth muscle to relax, thus increasing perfusion

Question 10

erythropoeitin

Answer 10

made in kidney, stimulates RBC production in bone marrow

Question 11

hemolytic disease of the newborn

Answer 11

when Rh- mother has an RH+ baby, during birth some Rh+ cells will sensitize mother, who’ll produce anti-Rh Abs. The second Rh+ baby will be killed, because these Ab can cross placenta

Question 12

chemotaxis

Answer 12

movement of WBCs directed by chemical signals

Question 13

megakaryocytes

Answer 13

give rise to platelets, RBCs, and WBCs

Question 14

thrombin

Answer 14

converts fibrinogen to fibrin (the clotting protein)

Question 15

what can decrease Hb’s affinity for O2?

Answer 15

binding fewer O2 (cooperativity)
more acidity
increased PCO2
increased temperature
^ as you can see, the last 3 are all hallmarks of a tissue during exertion. Therefore the O2 falls off Hb for the cell's use

Question 16

3 ways CO2 is transported

Answer 16

it turns to bicarbonate by carbonic anhydrase, an enzyme inside RBCs
Some can be bound to hemoglobin
And some can simply be dissolved in plasma (it is more soluble than O2)

Question 17

which 2 WBCs can squeeze through intracellular clefts?

Answer 17

macrophages, neutrophils because they are capable of amoeboid motility

Question 18

why is oncotic pressure important?

Answer 18

Proteins dissolved in plasma draw water back into capillaries. Salts are no substitute because their ions can also diffuse out

Question 19

chylomicrons

Answer 19

a lipoprotein package used to transport fats in the bloodstream

Question 20

the complement system

Answer 20

proteins called complements in blood bind to specific motifs on bacteria, leading to their destruction

Question 21

IgM

Answer 21

involved in initial immune response. Pentameric in blood; monomeric on B cell surfaces

Question 22

IgG

Answer 22

the main enzyme. Located in blood and it alone can cross placenta

Question 23

IgD

Answer 23

serves alongside IgM as the antigen receptor on B cell surfaces

Question 24

IgA

Answer 24

located in secretions including breast milk. Dimer structure.

Question 25

IgE

Answer 25

located in blood, used in allergic reactions

Question 26

epitope

Answer 26

the part of an antigen which Abs recognize

Question 27

hapten

Answer 27

the smaller molecule bound to a large molecule like a protein

Question 28

Abs have these functions against pathogens

Answer 28

binding to antigen may physically inactivate pathogen, such as preventing virus from entering cells The antibody's binding can also induce phagocytosis The antibody binding can also activate complement system to punch holes in cell membrane

Question 29

B cells

Answer 29

these are what produce antibodies Plasma cell - these actively produce antibody Memory cell - remains dormant in lymph nodes for the same infection in future

Question 30

T cells

Answer 30

T helpers - CD4. These activate B cells, killer cells, and others. It communicates with lymphokines and interleukins T killers - CD8. It destroys certain cell types: virus-infected, cancerous, and foreign cells from a transplant

Question 31

MHCI and II

Answer 31

MHC I are found on the exterior of every nucleated cell. They randomly bind peptides from inside the cell to display on the surface (so T cellscan find them) MHC II, whereas, are only found on the APCs. They phagocytose cells and display the fragments using MHC II. This will activate B cells

Question 32

bone marrow

Answer 32

synthesizes all blood types

Question 33

spleen

Answer 33

a lymphoid tissue, where B and T cells surveil lymph. Spleen also recycles aged RBCs

Question 34

thymus

Answer 34

the site where T cells mature

Question 35

difference btw Ab light and heavy chains?

Answer 35

while both have constant and variable domains, its only the heavy chains that define the class of antibody (IgM, IgA)

Question 36

Hb - O2 curve

Answer 36

it shifts LEFT in conditions of low acidity and CO2 and temp it shifts RIGHT when high acidity, CO2, temp However, PO2 does not shift the curve