Blood

Question 1

What are the 4 key components of blood

Answer 1

• red blood cells
• white blood cells
• plasma
• platelets

Question 2

What is plasma and why is it important?

Answer 2

• The liquid which carries the components in the blood, e.g. cells, platelets, amino acids,
• Plasma is important for the transport of carbon dioxide, digested food, urea, hormones and heat energy

Question 3

What are red blood cells, and why are they important?

Answer 3

Carry oxygen molecules from the lungs to all the cells in the body
- also contain haemoglobin: a red protein that combines with oxygen to allow for transport

Question 4

Adaptations of red blood cells for efficient gas exchange

Answer 4

• No nucleus: to create more space for haemoglobin
• Biconcave shape: to maximise surface area for oxygen to be absorbed
• Flexible: so they can fit through very narrow blood vessels
• Contain haemoglobin: a red protein that combines with oxygen to allow for transport

Question 5

What are white blood cells, and why are they important?

Answer 5

• They are a part of the immune system, which is the body’s defence against pathogens
• There are 2 types of WBCS:

Question 6

What are the functions of both types of white blood cell?

Answer 6

1. Phagocytic white blood cells
   - engulf and kill pathogen in a process called phagocytosis which is a non-specific function
2. lymphocytes
   - whose role is to produce antibodies by binding to a complimentary antigen (protein spike) on the surface of the pathogen.
   - Once antibodies begin to bind to the pathogen, the pathogens start to clump together resulting in it being easier for white blood cells to find them.

-If you become infected again with the same pathogen, the specific complementary
antibodies will be produced at a faster rate. The individual will not feel the symptoms of
the illness. They are said to be immune

Question 7

What are the names of the two types of white blood cells

Answer 7

• phagocytes

- lymphocytes

Question 8

What does it mean if you are ‘immune’ to a disease or infection

Answer 8

The specific complementary
antibodies created previously will be produced at a faster rate. The individual will not feel the symptoms of the illness. They are said to be immune

Question 9

What are platelets

Answer 9

Small fragments of cells that help blood clot

Question 10

How do platelets work

Answer 10

1) When the skin is broken (.e. there is a wound) platelets arrive to stop the bleeding
2) A series of reactions (the clotting cascade) occur within the blood plasma
3) Platelets release chemicals that cause fibrinogen proteins to form a mesh of insoluble
fibrin across the wound, trapping red blood cells and therefore forming a clot.
4) The clot eventually develops into a scab to protect the wound from bacteria entering

Question 11

What is a pathogen

Answer 11

Microorganisms that can cause disease

Question 12

In what state (kingdom) can pathogens occurs

Answer 12

• fungi
• bacteria
• protoctists
• viruses

Question 13

How do vaccines work?

Answer 13

1. dead or inactive pathogen is injected into the body. These carry antigens so even though they are harmless they still trigger an immune response
2. memory cells are also created with these cells, so if live pathogens of the same type enter the body, the antibodies will kill them faster and in greater numbers

Question 14

What are the three types of blood vessels

Answer 14

• arteries
• veins
• capillaries

Question 15

What is the role of the artery

Answer 15

• to carry blood at high pressure away from the heart

Question 16

What is the role of the vein

Answer 16

• to carry blood at a lower pressure back to the heart

Question 17

What is the role of capillaries

Answer 17

• these are involved in the exchange of materials at the tissue

Question 18

How are arteries adapted for their functions

Answer 18

• they have elastic fibres which allow them to expand

- they have very thick muscular walls and a smaller lumen

Question 19

How are veins adapted for their functions

Answer 19

• they have a thinner muscular wall and a bigger lumen to help blood flow
• they have valves to keep the blood flowing in the right direction

Question 20

How are capillaries adapted for their functions

Answer 20

• there are millions, and they carry blood very close to every cell in the body and help exchange substances like oxygen, carbon dioxide, glucose and water by diffusion
• they are one cell thick, so the diffusion distance is very short (increased rate)