Immune System

Question 1

identify the predominant cell type involved in acute inflammatory response

Answer 1

Neutrophils

• release chemotactic factors that recruit macrophages and monocytes to the site of infection

Question 2

identify the predominant cell type involved in chronic inflammatory response

Answer 2

Macrophages: important for phagocytosis and antigen presentation

Lymphocytes: immunological functions, B cells differentiate to produce antibodies and T cells have cytotoxic functions

Plasma cells: differentiated antibody producing B lymphocytes, the presence of these usually indicates the inflammation has been present for a considerable amount of time

Question 3

Function of the innate immune system in preventing invasion by pathogens

Answer 3

Two lines of defence:

1. Skin and mucous membranes
   - skin, sweat and sebaceous glands, mucous membranes, tears and saliva, gastric acid, acidic urine, normal flora
2. Internal defences
   immune cells or substances that treat all foreign cells I much the same way. These include:
   - Phagocytes (neutrophils, macrophages)
   - NK (natural killer) cells (immunological surveillance)
   - Inflammation
   - Fever

Question 4

Function of the adaptive immune system in preventing invasion by pathogens

Answer 4

The ability of the body to defend itself against specific invading agents

has both specificity and memory

Question 5

Identify the 2 types of adaptive immunity and the cells involved

Answer 5

Cell-mediated:

• occurs with intracellular pathogens.
• cytotoxic T cells directly attack invading antigens by releasing chemicals that kill cells on contact.

Antibody-mediated:
- B cells transform to plasma cells which synthesise and secrete antibodies which can bind to and inactivate antigens.

Question 6

What is the function of B lymphocytes in adaptive immunity?

Answer 6

become plasma cells which produce antibodies – directed against specific antigens in body fluids

Question 7

What is the function of T lymphocytes in adaptive immunity?

Answer 7

for cell-mediated immunity, directed against intracellular antigens (e.g. antigens on viruses)

Question 8

Role of the T helper cells?

Answer 8

control antibody-mediated (humoral) immune response of B cells

• produce interleukins and promote cell multiplication

Question 9

Role of T cytotoxic?

Answer 9

Effector cells of cell-mediated immunity

Question 10

T suppressor cells?

Answer 10

damp down immune response

Question 11

Describe lymphocytic leukaemia

Answer 11

A clonal malignant disorder of blood and blood-forming organs

• uncontrolled proliferation of malignant leucocytes
• lymphocytes overcrowd the bone marrow, then progressively travels elsewhere in the body
• can spread to lymph nodes

Question 12

Describe lymphoma

Answer 12

Neoplasms that develop from the proliferation of malignant lymphocytes in the lymphatic system.

• lymphocytes grow out of control in lymph nodes or organs of the lymphatic system

Question 13

Describe meningococcal meningitis

Answer 13

occurs as result of bacteria entering blood stream and infecting the meninges (protects the brain and spinal cord)

• can increase ICP leading to seizures, coma and death

Question 14

Describe meningococcal septicaemia

Answer 14

Occurs when bacteria enters blood stream, dividing rapidly leading to systemic inflammatory reaction

• bacteria releases toxins which cause blood poisoning

Question 15

Define disseminated intravascular coagulation and the pathophysiological processes that may lead to this.

Answer 15

Condition that causes abnormal blood clotting throughout the body’s blood vessels.

Two major mechanisms may trigger DIC:

1. release of tissue factor or thromboplastic substances into the circulation
2. widespread injury to endothelial cells

Question 16

What are the different types of shock and their cause?

Answer 16

Septic: shock from severe infection

Hypovolaemic: shock from hypotension

Cardiogenic: inadequate function of the heart, such as pump failure

Neurogenic: spinal cord trauma, with associated autonomic regulation

Anaphylactic: shock from hypersensitivity to allergies

Question 17

Describe the vascular and cellular responses that promote healing following a wound in the skin

Answer 17

1. homeostasis - coagulation
2. inflammation - macrophages invade clot and clear way debris and dead cells
3. proliferative
   - granulation tissue grows into wound
   - epithelialisation (unravels collagen and heals wound)
4. maturation - collagen fibres reorganize, tissue remodels and matures and increase in tensile strength

Question 18

Compare active vs. passive immunity

Answer 18

Active: long lasting immunity in which memory cells and antibodies are produced (naturally through infection, or by vax)

Passive: acquired by the transfer of antibodies from an immune person to a non-immune person (no memory cells develop, antibodies break down with time)

Question 19

Compare active vs. passive immunity

Answer 19

Active: long lasting immunity in which memory cells and antibodies are produced (naturally through infection, or by vax)

Passive: acquired by the transfer of antibodies from an immune person to a non-immune person (no memory cells develop, antibodies break down with time)