Lecture 9: Intro to Cardiovascular Physiology

Question 1

functions of the cardiovascular system?

Answer 1

• GAS TRANSPORT (delivers oxygen to tissues and returns CO2 to lungs)
• regulates body temp
• transports hormones to site of action
• transports waste
• transports nutrients
• stabilize pH
• transport cells that fight infection

Question 2

what is carbonic anhydrase and why is it so important

Answer 2

an enzyme that facilitates the reaction of CO2+H20 <–> HCO3- + H+

Question 3

CO2 in the blood generates ____?

Answer 3

H+

Question 4

why does the body have to constantly transport gases

Answer 4

b/c ATP is not stored, it must be continuously produced in cells by the oxidation of metabolic fuels (Krebs cycle + Oxidative phosphorylation)

Glucose (or fatty acids) + O2 –> CO2+H20+ATP

Question 5

What issues arise in the absence of carbonic anhydrase

Answer 5

inability to aerobically metabolize glucose and an accumulation of H+ ions

Question 6

why does an overabundance of positive charges caused by H+ ions interfere with RBCs

Answer 6

too much H+ damages RBCs by binding to hemoglobin and other proteins

protein function is compromised as H+ ions bind to the carboxyl group of the amino acids that make up the proteins, changing their conformation and therefore function

Question 7

pH of arterial blood

Answer 7

7.45
cannot survive if arterial blood is <6.8 or >8.0

Question 8

affects of acidosis

Answer 8

denaturation of metabolic enzymes and ion channels

decreased CNS function can lead to coma, death

Question 9

affects of Alkalosis

Answer 9

neurons become hyper-excitable

tingling, fasciculation, paralysis of respiratory muscles

Question 10

What are the components of the true circulatory system

Answer 10

muscular pump (heart)
fluid (blood)
conduits (blood vessels)

Question 11

what animals lack a true circulatory system and why

Answer 11

sponges, jellyfish and flatworms

they do have a contractile pumping device

Question 12

what are platelets formed from

Answer 12

megakaryocytes

Question 13

the liquid portion of blood is made of _____?

Answer 13

plasma (92% of plasma is water)

plasma contains proteins, electrolytes, gases in solution and nutrients

Question 14

intracellular vs extracellular fluid

Answer 14

intracellular - fluid contained w/in all body cells

extracellular - blood plasma & interstitial fluid bathes and surrounds cells)

Question 15

why is blood kept separate from interstitial fluid

Answer 15

bc it has specific transport functions and transport components that aren’t found in the interstitial fluid

Question 16

drains capillary beds and forms veins which deliver blood back to the heart (bulk flow)

Answer 16

VENULES

Question 17

carry blood away from the heart and branch into arterioles that feed capillary beds (bulk flow)

Answer 17

arteries

Question 18

mechanism by which dissolved substances move across the wall of blood vessels

Answer 18

diffusion

Question 19

what is bulk flow

Answer 19

blood flowing through the heart and blood vessels is via bulk flow

Question 20

What variables does bulk flow depend on

Answer 20

pressure, volume, diameter

Question 21

what is blood pressure (P) and what factors determine it

Answer 21

force of blood exerted against walls of vessels

determined by rate & pressure

Question 22

what is blood flow (F)

Answer 22

volume of blood flowing through a structure per unit time (ml/min)

Question 23

Blood flow rate is proportional to what

Answer 23

resistance

Question 24

what is resistance (R) and what factors determine it

Answer 24

opposition to blood flow through a vessel

determined by diameter and viscosity of the fluid

Question 25

what is cardiac output (CO)?

Answer 25

the volume of blood pumped each minute by one ventricle

Question 26

blood always flows from a region of higher pressure to a region of lower pressure by _____

Answer 26

bulk flow

Question 27

what causes blood flow to increase

Answer 27

- as pressure difference between 2 points increases - as resistance to flow decreases

Question 28

how does heartworm (dirofilaria immitis) cause primary cardiovascular dysfunction

Answer 28

heart worms lodge themselves in the Right Ventricle and Pulmonary Artery - this blocks flow to the pulmonary circuit and cardiac output - resulting in: shortness of breath and exercise intolerance due to the dramatic change in pressure differential

Question 29

How do blood worms (Strongylus vulgaris) affect cardiovascular function

Answer 29

bloodworms lodge themselves in mesenteric arteries - causes decreased blood flow to the intestines, causing ISCHEMIA --> decreased motility, secretion and absorption in the GI tract

Question 30

what type of circulatory system do fish have

Answer 30

single circuit: heart --> gills --> body --> heart

Question 31

How are fish able to have a low pressure system

Answer 31

b/c they have a lower metabolic rate and therefore their set point for body temp is much lower low pressure = low blood flow rate = less supply of gases and nutrients

Question 32

what are the advantages of a 4-chambered heart

Answer 32

- oxygenated blood is completely separate from deoxygenated blood - high pressure systemic circuit + low pressure pulmonary circuit - high pressure systemic circuit supports high metabolism -low pressure pulmonary circuit protects fragile lung tissue

Question 33

what is Patent ductus arteriosus (PDA

Answer 33

normally within a few minutes to days after birth, the ductus arteriosus closes in PDA, it remains open, resulting in abnormal blood flow b/w the pulmonary artery and aorta

Question 34

what would happen in the pulmonary and systemic circuits were not seperated

Answer 34

- volume overload of left heart - left ventricular and arterial dilation - left sided congestive heart failure

Question 35

what makes it possible for there to be limited mixing of deoxygenated/oxygenated blood in 3-chambered hearts like in frogs/reptiles

Answer 35

spiral valve in conus arteriosus

Question 36

in a 3 chambered heart, there is high blood pressure/flow to what system

Answer 36

systemic capillaries