Physiology of the Cardiovascular System

Question 1

Blood pressure

Answer 1

• this refers to the force per unit area that is exerted on the walls of the blood vessels by blood.
• its divided into systolic and diastolic components

Question 2

systolic/diastolic

Answer 2

it must be high enough to overcome the resistance created by arterioles and capillaries, but low enough to avoid damaging the vasculature and surrounding structures

Question 3

how is blood pressure maintained?

Answer 3

by baroreceptor and chemoreceptor reflexes.

Question 4

what does low blood pressure promote?

Answer 4

aldosterone and ADH (antidiuretic hormone) release. high blood osmolarity also promotes ADH release

Question 5

what does high blood pressure promote?

Answer 5

ANP - atrial natriueritic peptide release

Question 6

Gas and Solute Exchange

Answer 6

this occurs at the level of the capillaries and relies on the existence of concentration gradients to facilitate diffusion across the capillary walls.
-capillaries are also leaky, which aids in transport of gases and solutes

Question 7

Starling forces

Answer 7

these consist of hydrostatic pressure and osmotic (oncotic) pressure

Question 8

hydrostatic pressure and osmotic pressuer

Answer 8

this is the pressure of the fluid within the blood vessel, while osmotic pressure is the “sucking” pressure drawing water toward solutes.

Question 9

oncotic pressure

Answer 9

this is the pressure due to proteins.

Question 10

how they work together

Answer 10

hydrostatic pressure forces fluid out at the arteriolar end of a capillary bed; oncotic pressure draws it back in at the venule end

Question 11

oxygen being carried in hemoglobin

Answer 11

oxygen is carried by hemoglobin, which exhibits cooperative binding. In the lungs, there is a high partial pressure of oxygen, resulting in loading of oxygen onto hemoglobin. in the tissues, there is a low partial pressure of oxygen, resulting in unloading.

Question 12

cooperativity binding

Answer 12

due to this, each successive oxygen bound to hemoglobin increases the affinity of the other subunits, while each successive oxygen released decreases the affinity of the other subunits

Question 13

how is carbon dioxide carried in the blood?

Answer 13

in the form of carbonic acid, or bicarbonate and hydrogen atoms.
-CO2 is nonpolar and not particularly soluble, while bicarbonate, hydrogen ions, and carbonic acid are polar and highly soluble.

Question 14

what can cause a RIGHT shift in the oxyhemoglobin dissociation curve? what does it reflect?

Answer 14

high CO2 partial pressure, high [H+], low pH, high temp, and high concentration of 2,3-BPG
-this reflects a decreased affinity for oxygen

Question 15

Coagulation

Answer 15

(cont)

Question 16

clots

Answer 16

are compoesd of both coagulation factors (proteins) and platelets, and they prevent blood loss

Question 17

process

Answer 17

when the endothelium of a vlood vessel is damaged, it exposes the underlying connective tissue, which contains collagen and a protein called tissue factor.
when platelets come into contact with exposed collagen, they sense this is evidence of injury. in response, they release their contents and begin to aggregate.
-simultaneously, coagulation factors sensse tissue factor and initiate a complex activation cascade.

Question 18

whats the end result?

Answer 18

its the activation of prothrombin to form thrombin by thromboplastin.
-thrombin can then convert fibrinogen into fibrin. fibrin forms small fibers that aggregate into a woven structure, like a net, that captures RBCs and other platelets, forming a clot.