Circulation and Blood Vessels

Question 1

What is pulmonary circulation?

Answer 1

blood flow between the heart and lungs

Question 2

What is systemic circulation?

Answer 2

blood flow from the heart to the rest of the body

Question 3

What is cardiac/coronary circulation?

Answer 3

blood flow within the heart

Question 4

Describe the process of blood flowing around the body.

Answer 4

1. The process begins with the contraction of the right ventricle which pumps blood to the lungs via the pulmonary arteries.
2. Blood flows through the capillery beds in the lungs, where CO2 and O2 are exchanged.
3. The oxygen-rich blood then returns to the heart via the pulmonary veins to the left atrium of the heart.
4. The oxygen rich blood then flows into the left ventricle, which pumps the blood out to the body tissues through the systemic circuit.
5. The blood exits the heart through the aorta which moves blood to arteries throughout the body.
6. The arteries branch out and become arterioles, which then lead to capillary beds. O2 and CO2 are exchanged.
7. the capillaries rejoin to form venules and then veins.
8. The oxygen poor blood is them channeled into the superior vena cava.
9. The inferior vena cava drains the blood from the trunk and hindlimbs, which empty into the right atrium, which then flows into the right ventricle restarting the cycle.

Question 5

What’s the function of the artery and arteriole?

Answer 5

to transport blood away from the heart

Question 6

What are some examples of arteries and arterioles?

Answer 6

the aorta
pulmoary artery

Question 7

What’s the function of the veins and venules?

Answer 7

to transport the blood towards the heart

Question 8

What are some examples of veins and venules?

Answer 8

the vena cava and pulmonary vein

Question 9

What is the function of a capillary?

Answer 9

the material exchange between blood and body

Question 10

What materials are exchanged through the capillaries?

Answer 10

• gases (oxygen and carbon dioxide)
• nutrients
• waste

Question 11

How thick are the walls of capillaries? Why?

Answer 11

They have walls made up of one thin layer of cells which allow for rapid diffusion of materials from blood to surrounding tissue

Question 12

What control the flow of the blood into capillaries?

Answer 12

the sphincter muscles where arterioles branch into capillaries

Question 13

Are there muscles in the capillaries?

Answer 13

No. No smoothe muscles in the capillaries to control the diameter and therefore the blood flow

Question 14

What happens if blood is not required in an area?

Answer 14

sphincters will constrict

Question 15

What are the three layers in the arteries and veins?

Answer 15

• outermost layer
• middle layer
• innermost layer

Question 16

What’s in the outermost layer of the arteries and veins?

Answer 16

connective tissue

Question 17

What’s in the middle layer of the arteries and veins?

Answer 17

alternating circular bands of elastic fibres and smooth muscle. It provides elasticity to vessles

Question 18

What’s in the innermost layer of the arteries and veins?

Answer 18

epithelial cells that reduce friction and blood courses through vessels

Question 19

How thick is the innermost layer of the arteries and veins?

Answer 19

a single cell thick

Question 20

What characteristic do the elastic fibers near the heart have?

Answer 20

more elastic fibers

Question 21

What do the arteries further from the heart have more of?

Answer 21

more smooth muscle

Question 22

What does the structure of the arteries ensure?

Answer 22

continuous blood flow even when the heart is relaxed

Question 23

What’s in the middle layer of the artery? What do they do?

Answer 23

a thick middle elastic layer. It provides resistance to withstand high pressure

Question 24

What does the muscle tissue in an artery do?

Answer 24

helps maintain pressure by having contractile ability, which is the ability to expand and contract to keep blood moving

Question 25

What is a pulse?

Answer 25

a rhythmic expansion and contraction of an artery as blood moves through it

Question 26

What qualities must an artery have to feel a pulse?

Answer 26

• be large
• close to the skin surface
• against a bone or other firm structure

Question 27

What arteries are commonly used to detect a pulse?

Answer 27

radial, brochial or carotid arteries

Question 28

What are the characteristics of veins?

Answer 28

• thinner walls
• less elastic and muscle tissue
• larger circumference
• lacks elasticity but has greater capacity (veins hold twice as much blood as arteries)
• blood pressure is low
• blood flow is slower

Question 29

What contribute to returning the blood to the heart around veins?

Answer 29

surrounding skeletal muscles

Question 30

When do valves open in veins?

Answer 30

when surrounding muscles contract allowing blood to return to the heart?

Question 31

When do valves in the veins close?

Answer 31

when muscles relax so that blood cannot flow backwards.

Question 32

What are varicose veins?

Answer 32

deformed valves

Question 33

What are endotherms?

Answer 33

organisms that maintain an internal body temperature

Question 34

What are the physiological responses to cold in endotherms?

Answer 34

• shivering
• vasoconstriction

Question 35

What’s the physiological response to heat in endotherms?

Answer 35

• sweating
• vasodilation

Question 36

What is vasoconstriction?

Answer 36

muscles contract walls of blood vessels in exterminites, which leads to narrowed blood vessels and reduced blood flow, the blood is redirected to the torso

Question 37

What is vasodilation?

Answer 37

blood vessels in extermities dilated, which leads to increased blood flow at skin surface, excess heat is released into the environment.