Second line of defence

Question 1

What does the second line of defence include

Answer 1

Phagocytosis, Inflammation, Fever

Question 2

What does the immune system consist of

Answer 2

Lymph nodes, Lymph vessels, Lymphoid tissues (Thymus, Spleen, Bone marrow), Leucocytes (White blood cells)

Question 3

What does the immune system do

Answer 3

Carries out both specific and non-specific responses

Question 4

Lymph vessel and movement through it

Answer 4

Lymph vessel has valves, blind-ended tubes, thin, not muscular, Lymph moves through the lymph vessel via contractions of the muscle pushing the lymph up which is then stopped from going back down by the valves

Question 5

What does the lymphatic system do

Answer 5

Drains intercellular fluid back to the heart and circulatory system

Question 6

White blood cells/leucocytes

Answer 6

can leave the blood capillaries and migrate to places of infection or injury

Question 7

Macrophages

Answer 7

leucocyte that can undergo a specific and non-specific defence, phagocytes, release substances which destroy micro-organisms

Question 8

Lymphocytes (B and T cells)

Answer 8

leucocytes that can only undergo a specific defence only, produced in bone marrow and lymphoid tissue, circulate through tissue, blood, lymph

Question 9

Phagocyte

Answer 9

white blood cell that is capable of engulfing and digesting micro-organisms and cell debris

Question 10

Cause of inflammation

Answer 10

Response to tissue damage

Question 11

Purpose of inflammation (4)

Answer 11

Reduce spread, destroy and stop further entry of pathogens, Remove damaged tissue/cell debris, Begin repair of damaged tissues

Question 12

5 signs of inflammation

Answer 12

Redness, heat, swelling, pus, pain

Question 13

What causes redness

Answer 13

increased blood flow, increased Vaso dilation and increased capillary permeability

Question 14

What causes heat

Answer 14

increased blood flow, increased Vaso dilation and increased capillary permeability

Question 15

What causes swelling

Answer 15

leaking fluid from the blood vessels, increased Vaso dilation and increased capillary permeability

Question 16

What causes pus

Answer 16

dead phagocytes that have been drawn to the area

Question 17

What causes pain

Answer 17

pain receptors being stimulated by increased blood flow pressing on them

Question 18

Inflammatory response

Answer 18

Non-specific, When cell damage occurs, mast cells (specialised leucocytes that line tissues) release histamine and heparin into intercellular fluid, Histamine increases blood flow to the area by increasing capillary permeability (spreads lining cells out) and causing blood vessels to dilate, Heparin prevents immediate clotting which allows leucocytes to get to the area that is infected/injured, Phagocytes are attracted by chemicals from the mast cells and move in to conduct phagocytosis

Question 19

Fever

Answer 19

Non-specific response, elevation of body temperature

Question 20

Why are fevers beneficial (4)

Answer 20

Increases production of killer T cells (which speeds up the cell mediated immune response, Increases metabolic rate which speeds up tissue repair, Increases heart rate/blood flow which enables lymphocytes to reach sites of infection faster, Creates non-optimum temperature/high temperature which inhibits/kills pathogen

Question 21

When can a fever be harmfull

Answer 21

body temperature gets too high (44-45 degrees) as enzymes start to denature

Question 22

What causes a fever

Answer 22

Pathogens release chemicals called pyrogens which causes the sensors in the hypothalamus to increase body temperature, Macrophages respond to the pathogen by ingesting it, releasing a chemical called interleukin 1 which the hypothalamus responds to by increasing the bodies temperature

Question 23

When the body feels cold whilst a fever is occuring

Answer 23

happens because the “internal thermostat” is raised meaning normal temp=cold, causes body to respond by shivering and vasoconstricting the blood vessels in your skin in an attempt to warm up

Question 24

Fever has broken

Answer 24

when infection is over and there are no more pyrogens meaning the hypothalamus will re-set the set point back to 37.5 meaning the body needs to cool down by sweating and vaso-dilation