Lecture 10: The immune system part 1

Question 1

Diseases

Answer 1

Impairs the normal function of an organism

Question 2

What are the types of diseases

Answer 2

Communicable diseases
Non-communicable diseases

Question 3

What causes Disease?

Answer 3

Pathogens, Viruses, bacteria, protists or fungi
Direct contact through water/ air
Bacteria and viruses may rapidly reproduce inside the body / produce toxins that damage tissues and make you feel ill
Viruses live and reproduce inside cells causing cell damage

Question 4

Primary defence barriers

Answer 4

Eyes
Nose and mouth
Skin
Stomach acid
Breathing system (trachea and bronchi)
Blood clotting

Question 5

What prevents the entry of pathogens into the body?

Answer 5

goblet cells/mucous membranes/platelets/skin

Question 6

Binary fission

Answer 6

Replication of circular DNA and plasmids
Division of cytoplasm to produce 2 daughter cells each with a single copy of the circular DNA and variable number of copies of plasmids

Question 6

Antigens on blood cells

Answer 6

Blood types
Inherited via a single gene
Presence or absence of antigens
Glycoprotein

Question 6

Blood group O

Answer 6

no antigens
Anti A and Anti B antibodies

Question 6

Blood group A

Answer 6

Antigens = A
Anti B antibodies

Question 6

Blood group B

Answer 6

Antigens = B
Anti A antibodies

Question 7

The Immune response

Answer 7

White blood cells leukocytes -> phagocytes -> macrophages -> neutrophils (NON SPECIFIC)
White blood cells leukocytes -> lymphocytes -> B lymphocyte/T lymphocyte (Specific)

Question 8

phagocytosis

Answer 8

Cytokines (proteins that act as messenger molecules) are released by cells at the site of an infection
Opsonins (molecules in the blood) attach to foreign antigens to aid phagocytosis

Question 9

Phagocytosis-Neutrophil (first WBC to respond to pathogen)

Answer 9

Neutrophil are attracted to wounds in response from cytokines
Receptors on neutrophil attach to opsonin
Cytoplasm moves round and engulfs Pathogen
Special vacuole- Phagosome
Lysosomes move towards the phagosome
Phagolysosome - lysozyme

Question 10

Phagocytosis-Macrophage

Answer 10

All the same steps as neutrophils – additional function (antigen presentation)
At the last stage, glycoproteins (MHC) from the cytoplasm move to the phagolysosome and bind to the antigen molecules
MHC – major histocompatibility complex
Forms MHC-antigen complex
This moves to the cell surface membrane - antigens are presented to the exterior of the cell – APC (Antigen presenting cell) – presents to lymphocytes

Question 11

Antibodies – B-lymphocytes

Answer 11

Immunoglobulins
Several different types
Act as opsonins, tagging foreign bodies for phagocytosis
Stick pathogens together (agglutination)
Stick to bacterial toxins