Lecture Exam 3 - 34H) - 34I) Circulation and Gas Exchange – Mammals specifically humans

Question 1

• Atria has what kind of walls?

Answer 1

thin

Question 2

• What does the atria do?

Answer 2

Receives blood into the heart to drive it into the ventricles

Question 3

• The ventricles have what kind of walls?

Answer 3

thick

Question 4

• So what does the Atrioventricular valve do? Specially How?

Answer 4

it prevents backflow between atria and ventricles – it closes in

Question 5

• How are semilunar valves the 2 exit points from the heart?

Answer 5

Prevents backflow to the right ventricle

Question 6

• What is the beat origin of the heart?

Answer 6

Via the SA node as an electrical impulse that causes the walls of the atria to contract

Question 7

• If cardiac muscles are autorhythmic, what does this then mean?

Answer 7

No signals from the nervous system

Question 8

• In the Cardiac Cycle, what is the difference between systole vs diastole? What else does it do?

Answer 8

Systole: Contraction – of the ventricles. Diastole: relaxation – of the arteries. Allows blood to move from our lungs to our heart to the rest of the body

Question 9

• What is the Cardiac Cycle about?

Answer 9

About the complete sequence of pumping and filling

Question 10

• In the Cardiac Cycle, what is the pace maker called? And what does it do?

Answer 10

Sinoatrial (SA) node which set the contraction for the cardiac muscle

Question 11

• How does the atrioventricular (AV) node relay messages? Is it done on the top or bottom of the heart? Then where else?

Answer 11

Top – ventricles – b/c remember it prevents backflow back to the ventricles

Question 12

• Arteries are much thicker wall so they are dealing with pumping of the ___

Answer 12

heart

Question 13

• What are Endothelium?

Answer 13

are epithelial cells lining the central cavities

Question 14

• How does Endothelium help with friction?

Answer 14

It decreases the amount of friction to allow blood to move through vessels – also, as we get older and build up plaque in our veins it decreases the amount of blood flow and becomes a problem

Question 15

• Are Capillaries thin walled?

Answer 15

Yes

Question 16

• Capillaries are the size of what?

Answer 16

red blood cells

Question 17

• Do capillaries have endothelium?

Answer 17

They do - remember they are the walls of the Capillary beds, which are thin

Question 18

• How does blood-interstitial fluid exchange within the Capillaries?

Answer 18

Due to the thin walls – where diffusion also takes place.

Question 19

• what do red blood cells have to do with Capillary?

Answer 19

As red blood cells pass through the capillaries, they drop off the oxygen that your cells need to live, and pick up the waste gas, carbon dioxide

Question 20

• In a capillary, what does the thin basal lamina surround?

Answer 20

The endothelium – it’s thin layered

Question 21

• blood-interstitial fluid exchange only occur in Capillaries due to what?

Answer 21

The thin walls in Capillaries.

Question 22

• What is the outer layer of Arteries & Veins?

Answer 22

elastic fiber, collagen connective tissue

Question 23

• What is the inside layer of Arteries & Veins?

Answer 23

smooth muscle to allow smooth movement of blood; elastic fibers

Question 24

• What does blood flow velocity do?

Answer 24

it slows arteries and arterioles – blood flow is slowest in Capillaries

Question 25

• In Blood Flow Velocity, what is Vasoconstriction?

Answer 25

Results in the narrowing of the blood vessels/smooth muscles in arteriole walls contract & increases blood pressure up from where it occurs

However - the widening of blood vessels - is Vasodilation - blood pressure decreases

Question 26

• So what is blood flow velocity –

Answer 26

moves slow when it moves into the arteries and then moves slower into arterioles then makes it way into the Capillaries

Question 27

• How do smooth muscles in arteriole walls contract? Are they narrow?

Answer 27

They are narrow – as the smooth walls in the tunica media contract, it makes the lumen narrower

Question 28

• In Vasodilation, do smooth muscles relax and open?

Answer 28

Yes

Question 29

• In Vasodilation, what happens to blood pressure up from where it occurs?

Answer 29

it decreases blood pressure