The Blood and Immunity

Question 1

What does the blood consist of and how much percentage of is there.

Answer 1

RBC (red blood cells), WBC ( white blood cells) and plasma and platelets
45% = RBC, WBC and platelets
55%= plasma

Question 2

Red blood cell structure

Answer 2

Biconcave discs containing no nucleus but plenty of protein haemoglobin

Question 3

White blood cell structure

Answer 3

Large cells containing nucleus, different types have slightly different structure and functions.

Question 4

Platelets structures

Answer 4

Fragments of cells

Question 5

Plasma structure

Answer 5

straw coloured liquid

Question 6

Role of plasma and what it carries and importance.

Answer 6

Plasma is the liquid which carries the components in the blood, e.g. cells, platelets, amino acids, hormones etc.
Important for transport of CO2, digested food, urea, hormones and heat energy.

Question 7

Where does the plasma carry carbon dioxide

Answer 7

Carries waste CO2 away from respiring cells to the lungs for exhalation

Question 8

Where does the plasma carry digested food

Answer 8

Carries digested food(amino acids, glucose) to cells for respiration or assimilation ( absorption of nutrients)

Question 9

Where does the plasma carry Urea

Answer 9

Waste made in the liver as a result of the deamination of of amino group carried by plasma to kidney for excretion in urine.

Question 10

Why does the plasma carry Hormones

Answer 10

Made in endocrine glands, secreted into plasma and sent to target organ to simulate changes in body conditions.

Question 11

Where does the plasma carry Heat energy

Answer 11

Plasma is mainly made out of H2O which has high heat capacity so in crucial for maintain balanced temperature in body.

Question 12

What does the RBC do

Answer 12

Red blood cells transport oxygen around the body from the lungs to cells which require it for aerobic respiration

Question 13

Why does RBC have haemoglobin and what is haemoglobin

Answer 13

Has large quantity of haemoglobin (protein that combines oxygen ) to allow cell to transport oxygen to respiring cells.

Question 14

Why does RBC have no nucleus

Answer 14

No nucleus so more space in the cell for haemoglobin, allowing more oxygen to be transported to respiring cells.

Question 15

Why are RBC small and flexible

Answer 15

Allows them to squeeze through narrow capillaries and blood vessels without getting stuck.

Question 16

Why does RBC have a biconcave

Answer 16

Flattened disc to allow greater surface area to volume ratio to increase diffusion rate of oxygen.

Question 17

What does the WBC do

Answer 17

White blood cells are part of the body’s immune system, defending against infection by pathogenic microorganisms

Question 18

What are the two main types of WBC

Answer 18

two main types, phagocytes and lymphocytes

Question 19

What does Phagocytes do and how.

Answer 19

• Carry out phagocytosis by engulfing and digesting pathogens.
  1. have a sensitive cell surface membrane that can detect chemicals produced by pathogenic cells
  2. Once encountered, they release digestive enzymes to digest it
  3. The pathogenic cells can be recognised easily by their multi-lobed nucleus and their ability to change shape easily.
  4. They do it to all pathogenic cells they encounter and it is known as non-specific immune response.

Question 20

What does Lymphocytes do and how.

Answer 20

• Produce antibodies to destroy pathogenic cells and antitoxins to neutralise toxins released by pathogens
  1. Make antibodies ( protein molecules) which stick to antigens on a pathogenic cell.
  2. This triggers pathogen to be destroyed by enzymes split opening the pathogen cell membrane.
  3. It makes it easier for Phagocytes to find it.
  4. Also causes agglutination (clumping together) of pathogens making it harder for them to damage our cells and make it easier for phagocytes to find.

Question 21

What are some features of the Lymphocytes and what is immunity

Answer 21

1. The antigens they produce are very specific to to that type of cell.
2. Since each lymphocyte only make one type of antibody makes it harder for body to find specific one for that pathogen making you sick.
3. After the first time Lymphocytes produce memory cells retain the instructions for making those specific antibodies for that type of pathogen.
4. Therefore it can produce antigens before the pathogen cells can make you sick
   * This is known as immunity as you can’t get sick from the same pathogen the second time.

Question 22

What is vaccination and how does it work?

Answer 22

1. Involves introducing small quantities of dead or inactive forms of pathogens to enter the body.( can’t lead to a disease in a patient.)
2. The WBC are stimulated to produces antibodies against the dead pathogen, they attach themselves to the antigen in order to make memory cells
3. Same time WBC divides by mitosis and make many copies of themselves.
4. These memory cells or WBC stay in the blood for decades, so if the same pathogen enters the body, antibodies are produced quick and infection would be prevented.

Question 23

What are platelets and what’s the need for blood clotting.

Answer 23

Platelets are blood fragments which are involved in blood clotting. This prevents continued / significant blood loss from wounds. A scab is formed sealing the wound with insoluble patch that prevents entry of microorganisms that could cause infection and remains until skin heals under it.

Question 24

How are platelets involved in the clotting of blood?

Answer 24

1. When there is a wound collagen is exposed which attracts platelets to the area.
2. They quickly build a barrier preventing much blood loss.
3. Platelet release chemicals that cause soluble fibrinogen proteins to convert into insoluble fibrin
4. This forms a insoluble mesh across the wound trapping RBC therefore forming a clot.(the fibrin make the clot stronger. )
5. clot eventually dries and develops into a scab to protect the wound from bacteria entering