8.1: Blood Vessels

Question 1

what type of circulatory system do humans have?

Answer 1

closed, double circulatory

Question 2

what does it mean when you say “double circulatory system”?

Answer 2

blood passes twice through the heart in a single cycle

Question 3

what does it mean when you say “closed circulation”?

Answer 3

blood is transported by vessels

Question 4

pulmonary cycle

Answer 4

blood goes from heart to lungs & back

Question 5

pulmonary artery

Answer 5

deoxygenated blood from heart to lungs

Question 6

pulmonary vein

Answer 6

deoxygenated blood from lungs to heart

Question 7

systemic cycle

Answer 7

blood goes from heart to body and back

Question 8

ARTERIES

role

Answer 8

carry blood away from heart

Question 9

ARTERIES

composition of outer later

Answer 9

elastic fibres and muscle fibres, proportion varies acc. to role

Question 10

ARTERIES

composition of middle layer

Answer 10

smooth muscle + collagen and elastic fibres

Question 11

ARTERIES

lumen

Answer 11

relatively narrow

Question 12

ARTERIES

inner layer

Answer 12

consists of squamous epithelial cells

Question 13

VEINS

role

Answer 13

carry blood to heart

Question 14

VEINS

outer layer

Answer 14

mostly collagen fibres, thin

Question 15

VEINS

middle layer

Answer 15

some smooth muscle

Question 16

VEINS

inner layer

Answer 16

consists of squamous epithelial cells

Question 17

VEINS

lumen

Answer 17

relatively large

Question 18

VEINS

semilunar valves - function

Answer 18

prevent backward flow of blood

Question 19

VEINS

name of valves

Answer 19

semilunar

Question 20

CAPILLARIES

role

Answer 20

link arterioles and venules, taking blood to nearly every cell in body

Question 21

CAPILLARIES

diameter

Answer 21

7 micrometres

Question 22

CAPILLARIES

where are capillary beds not present? (3)

Answer 22

in the brain, cornea and cartilage

Question 23

ELASTIC ARTERIES

function

Answer 23

carry blood at very high pressure

Question 24

ELASTIC ARTERIES

structure

Answer 24

contain a lot of elastic fibres in the middle layer

Question 25

MUSCULAR ARTERIES

function

Answer 25

control the volume of blood going to a particular organ

Question 26

MUSCULAR ARTERIES

structure

Answer 26

high proportion of smooth muscle in walls

Question 27

AORTA

overall diameter

Answer 27

2.5 cm

Question 28

AORTA

wall thickness

Answer 28

2 mm

Question 29

AORTA

impact of thick walls

Answer 29

high strength, resilience and elasticity

Question 30

AORTA

blood pressure

Answer 30

approx. 120 mmHg

Question 31

CAPILLARIES

blood pressure

Answer 31

approx. 10 - 35 mmHg

Question 32

VEINS

blood pressure

Answer 32

less than 5 mmHg

Question 33

ARTERIOLES

structure

Answer 33

very narrow, with high amounts of smooth muscle. walls also have a nerve supply.

Question 34

ARTERIOLES

benefits of being narrow (2)

Answer 34

blood slows down, lowering pressure and reducing the chances of edema (build-up of tissue fluid)

Question 35

ARTERIOLES

role of nerve supply

Answer 35

cause vasoconstriction and vasodilation, depending on body’s requirements

Question 36

ARTERIOLES

vasodilation

Answer 36

smooth muscles relax = high blood flow to an area

Question 37

ARTERIOLES

vasoconstriction

Answer 37

smooth muscles contract = lowered blood flow to an area (allows for diversion of blood flow)

Question 38

ARTERIOLES

blood pressure

Answer 38

approx. 70 mmHg