Unit 3 - Blood and blood vessels

Question 1

What is plasma?

Answer 1

Liquid component of blood

Question 2

What is the function of plasma?

Answer 2

Transports dissolved substances e.g glucose, amino acids, mineral ions, hormones, albumin and fibrinogens

Question 3

Why is albumin important?

Answer 3

It helps to maintain osmotic pressure

Question 4

Why are fibrinogens important?

Answer 4

Involved in blood clotting

Question 5

What are platelets?

Answer 5

Small fragments of cells

Question 6

Which is the function of platelets?

Answer 6

Start the process of blood clotting

Question 7

What triggers blood clotting?

Answer 7

• a rough surface

- exposure to air

Question 8

What is the function of erythrocytes?

Answer 8

-carry oxygen and carbon dioxide around the blood

Question 9

What are the characteristics of granulocytes?

Answer 9

• lobed nucleus

- granular cytoplasm

Question 10

What are the characteristics of monocytes?

Answer 10

• kidney bean shaped nucleus

- cytoplasm not granular

Question 11

What are the characteristics of lymphocytes?

Answer 11

• large round nucleus

- cytoplasm not granularr

Question 12

What is the function of granulocytes?

Answer 12

• some phagocytic

- involved in allergy/inflammation

Question 13

What is the function of monocytes?

Answer 13

-involved in defence against pathogens

Question 14

What is the function of lymphocytes?

Answer 14

-produces new antibodies

Question 15

What are the functions of blood as a whole?

Answer 15

• transport of oxygen and carbon dioxide to and from respiring cells
• transport hormones
• transport nitrogenous waste products from cells to excretory organs
• transporting cells and antibodies involved in the immune response
• helps to maintain steady body temperature
• acts as a buffer to minimise pH changes

Question 16

What are the 3 layers of arteries called?

Answer 16

Tunica intima
Tunica media
Tunica externa

Question 17

What makes up the tunica initima?

Answer 17

squamous epithelial

Question 18

What are the functions of the arteries?

Answer 18

Carry oxygenated blood away from the heart apart from the pulmonary artery

Question 19

What is bloodflow into arteries like?

Answer 19

• high pressure
• pulsatile
• fast

Question 20

Why do arteries need to maintain high pressure of the arteries?

Answer 20

So that blood can reach tissues in the body

Question 21

What makes up the tunica media of the arteries?

Answer 21

Smooth muscle and elastic fibres

Question 22

What makes up the tunica externa of the arteries?

Answer 22

Collagen

Question 23

What do the elastic fibres in the tunica media of the arteries do?

Answer 23

Stretch to receive blood and recoil between contractions of the heart which helps to maintain pressure and even out bloodflow

Question 24

What is the function of collagen in the tunica externa of arteries?

Answer 24

Prevents blood vessels from bursting under high pressure

Question 25

Why is the tunica initmia of arteries smooth?

Answer 25

So blood flows over it easily

Question 26

What does contact of blood with artery walls cause?

Answer 26

• friction
• slows blood down
• evens out pulsatile flow

Question 27

What is the function of laminas?

Answer 27

Separate the inner from middle and the middle from outer

Question 28

What is the function of basement membranes?

Answer 28

Anchors the endothelium to the connective tissue and supports endothelial cells

Question 29

What is the function arterioles?

Answer 29

regulate the flow of blood into capillaries

Question 30

Do arterioles have a higher proportion of smooth muscle than arteries?

Answer 30

Yes

Question 31

What is the function of the smooth muscle?

Answer 31

It is neuronally stimulated causing vasoconstriction of vasodilation which controls the flow of blood into capillaries e.g during body temperature regulation

Question 32

Why do arterioles have a lower proportion of elastin in their walls compared to arteries?

Answer 32

The blood flow isn’t very pulsatile

Question 33

Why is blood slower in the arterioles?

Answer 33

Due to friction with the vessel walls

Question 34

How does the slightly wider lumen in arterioles affect pressure?

Answer 34

Reduces it slightly

Question 35

What is the function of capillaries?

Answer 35

To exchange substances between the blood and tissues

Question 36

What is the advantage of capillaries being one cell thick?

Answer 36

Gives a short diffusion path

Question 37

What is the advantage of blood flow being slow through capillaries?

Answer 37

Gives a longer time for the exchange of substances

Question 38

Why is the blood flow low pressure through capillaries?

Answer 38

Prevents them from bursting

Pressure is spread across many vessels

Question 39

What is blood flow like through capillaries?

Answer 39

Smooth, low pressure, slow

Question 40

What is the function of venules?

Answer 40

to link capillaries to veins

Question 41

What are the walls of venules mostly made of?

Answer 41

Collagen

Question 42

Why do venules have a thin tunica media?

Answer 42

low pressure flow doesn’t require muscle or elastic fibres

Question 43

Why do veins have a wide lumen?

Answer 43

To accommodate the large volume of blood carried

Question 44

What is the blood flow through veins like?

Answer 44

Very slow, low pressure, smooth

Question 45

Why are valves present in veins?

Answer 45

Prevent backflow

Question 46

What 3 mechanisms aid blood flow back to the heart?

Answer 46

-Movement of skeletal muscles contract/relax and push
blood through veins as they lie near the surface
-Pocket valves prevent backflow
-Breathing mechanism causes negative pressure in the thorax so pulls blood towards the heart