Unit 3 - Blood and blood vessels Flashcards Preview

LGS A-Level OCR Biology > Unit 3 - Blood and blood vessels > Flashcards

Flashcards in Unit 3 - Blood and blood vessels Deck (46)
Loading flashcards...
1
Q

What is plasma?

A

Liquid component of blood

2
Q

What is the function of plasma?

A

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

3
Q

Why is albumin important?

A

It helps to maintain osmotic pressure

4
Q

Why are fibrinogens important?

A

Involved in blood clotting

5
Q

What are platelets?

A

Small fragments of cells

6
Q

Which is the function of platelets?

A

Start the process of blood clotting

7
Q

What triggers blood clotting?

A
  • a rough surface

- exposure to air

8
Q

What is the function of erythrocytes?

A

-carry oxygen and carbon dioxide around the blood

9
Q

What are the characteristics of granulocytes?

A
  • lobed nucleus

- granular cytoplasm

10
Q

What are the characteristics of monocytes?

A
  • kidney bean shaped nucleus

- cytoplasm not granular

11
Q

What are the characteristics of lymphocytes?

A
  • large round nucleus

- cytoplasm not granularr

12
Q

What is the function of granulocytes?

A
  • some phagocytic

- involved in allergy/inflammation

13
Q

What is the function of monocytes?

A

-involved in defence against pathogens

14
Q

What is the function of lymphocytes?

A

-produces new antibodies

15
Q

What are the functions of blood as a whole?

A
  • 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
16
Q

What are the 3 layers of arteries called?

A

Tunica intima
Tunica media
Tunica externa

17
Q

What makes up the tunica initima?

A

squamous epithelial

18
Q

What are the functions of the arteries?

A

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

19
Q

What is bloodflow into arteries like?

A
  • high pressure
  • pulsatile
  • fast
20
Q

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

A

So that blood can reach tissues in the body

21
Q

What makes up the tunica media of the arteries?

A

Smooth muscle and elastic fibres

22
Q

What makes up the tunica externa of the arteries?

A

Collagen

23
Q

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

A

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

24
Q

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

A

Prevents blood vessels from bursting under high pressure

25
Q

Why is the tunica initmia of arteries smooth?

A

So blood flows over it easily

26
Q

What does contact of blood with artery walls cause?

A
  • friction
  • slows blood down
  • evens out pulsatile flow
27
Q

What is the function of laminas?

A

Separate the inner from middle and the middle from outer

28
Q

What is the function of basement membranes?

A

Anchors the endothelium to the connective tissue and supports endothelial cells

29
Q

What is the function arterioles?

A

regulate the flow of blood into capillaries

30
Q

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

A

Yes

31
Q

What is the function of the smooth muscle?

A

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

32
Q

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

A

The blood flow isn’t very pulsatile

33
Q

Why is blood slower in the arterioles?

A

Due to friction with the vessel walls

34
Q

How does the slightly wider lumen in arterioles affect pressure?

A

Reduces it slightly

35
Q

What is the function of capillaries?

A

To exchange substances between the blood and tissues

36
Q

What is the advantage of capillaries being one cell thick?

A

Gives a short diffusion path

37
Q

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

A

Gives a longer time for the exchange of substances

38
Q

Why is the blood flow low pressure through capillaries?

A

Prevents them from bursting

Pressure is spread across many vessels

39
Q

What is blood flow like through capillaries?

A

Smooth, low pressure, slow

40
Q

What is the function of venules?

A

to link capillaries to veins

41
Q

What are the walls of venules mostly made of?

A

Collagen

42
Q

Why do venules have a thin tunica media?

A

low pressure flow doesn’t require muscle or elastic fibres

43
Q

Why do veins have a wide lumen?

A

To accommodate the large volume of blood carried

44
Q

What is the blood flow through veins like?

A

Very slow, low pressure, smooth

45
Q

Why are valves present in veins?

A

Prevent backflow

46
Q

What 3 mechanisms aid blood flow back to the heart?

A

-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