circulatory and vascular system

Question 1

what is this system divided into

Answer 1

divided into 2 : taking blood away from the heart (arteries) and back to the heart (veins)

Question 2

what type of blood does the left side of the heart carry?

Answer 2

oxygenated blood

Question 3

what type of blood does the right side of the heart carry

Answer 3

deoxygenated blood

Question 4

name some types of blood vessels

Answer 4

• elastic conducting arteries
• muscular distributing arteries
• arterioles
• capillaries
• venules
• veins

Question 5

what is the tunica intima

Answer 5

• its the innermost layer
• endothelium
• thin/single layer
• has tight junctions to prevent leaks
• produces vasoactive substances (dialate or constrict)

Question 6

what is the tunica media

Answer 6

• its the middle layer
• connective tissue and smooth muscle
• adds strength so can withstand a lot of pressure
• has internal/external lamina
• has nerves for sympathetic innervation
• its important for the control of blood pressure as can change diameter.

Question 7

what is the tunica adventitia/ externa

Answer 7

• connective tissue (collagen and elastin)
• controls over expansion /collapse
• vasa-vasorum (needed if blood vessels are too big- so own blood supply) in some large vessels

Question 8

what is endothelial dysfunction

Answer 8

when the large blood vessels on the hearts surface constrict instead of dialating

Question 9

composition of capillaries

Answer 9

• very small lumen
• wall is one cell thick (endothelium)

Question 10

composition of arteries

Answer 10

• small lumen
• thick layer of muscle and elastic fibres
• thick outer wall

Question 11

composition of veins

Answer 11

• large lumen
• thin layer of muscle and elastic fibres
• fairly thin outer wall
• has valves

Question 12

what is the difference between arteries and veins

Answer 12

• veins have valves and arteries don’t
• arteries have thick layers whereas veins have thin layers

Question 13

how is the diameter of blood vessels regulated

Answer 13

by mediators which are released by the inner layer endothelial cell. these mediators are called vasoconstrictors and vasodialators

Question 14

what are examples of vasoconstrictors

Answer 14

noradrenalin, endothelin, thromboxane and adrenaline

Question 15

what are examples of vasodialators

Answer 15

histamine, nitric acid, bradykinin and adenosine

Question 16

composition of venules

Answer 16

• narrow lumen
• no tunica media

Question 17

composition of medium diameter veins

Answer 17

• thin tunica media
• some smooth muscle

Question 18

composition of large diameter veins

Answer 18

• thick tunica externa
• relatively thick tunica media

Question 18

what is blood flow controlled by

Answer 18

the vasoconstriction or dialation of small arteries or arterioles

Question 18

composition of larger veins

Answer 18

• has valves
• varicose veins form in valves

Question 19

what are precapillary sphincters

Answer 19

they help control blood flow in capillaries

Question 20

what are smooth muscle contractions and relaxation of precapillary sphincters regulated by

Answer 20

by local (metabolism) and extrinsic (neural) mechanisms

Question 21

what happens to blood flow to skeletal muscle and intestines when exercising

Answer 21

the blood flow to skeletal muscles increases but flow to the intestines decreases

Question 22

Are there valves in the veins in the brain

Answer 22

No

Question 23

Why is the flow slow in the capillaries for gas exchange

Answer 23

For better gas and nutrients exchange

Question 24

Describe the exchange of fluids in the capillaries

Answer 24

There is a net of loss of fluid that goes in the interstitial fluid causing a fall in blood pressure. The plasma protein causes an osmotic gradient. The fluids then form urine in the kidneys and lymph

Question 25

Where are lymphatic capillaries found and not found

Answer 25

They are found in tissues all over the body but not in the CNS, bone marrow and epidermis

Question 26

Why is the fluid that enters the lymph capillaries returned to the blood

Answer 26

To prevent edema (swelling fit to accumulated fluid) and to maintain normal blood pressure and volume

Question 27

What vein does the lymph flow to

Answer 27

Subclavian vein

Question 28

What type of white blood cells does lymphatic fluid contain and not contain

Answer 28

Contains white blood cells but no red blood cells

Question 29

What system are the lymph nodes also part of

Answer 29

Immune system