Lecture 20: Intro to blood and immune

Question 1

What are the components of blood?

Answer 1

Plasma - water and dissolved substances
White blood cells
Platelets
Red blood cells

Question 2

What is the function of red blood cells?

Answer 2

Carry oxygen in blood

Question 3

What is the function of white blood cells?

Answer 3

Involved in immune response

Question 4

What is the function of platelets?

Answer 4

Blood clotting

Question 5

What are neutrophils?

Answer 5

White blood cells that engulf pathogens - phagocytosis

Question 6

What are lymphocytes?

Answer 6

B and T cells - they have a range of functions e.g. carry receptors to sense pathogens

Question 7

What are monocytes?

Answer 7

Precursor to macrophages (phagocytes)

Scavenge and sense pathogens

Question 8

What are the two functions of immune system?

Answer 8

Differentiate between self and non-self antigens

Seek and destroy non-self antigens

Question 9

Define pathology

Answer 9

Study of diseases and how they progress

Question 10

Define pathogen

Answer 10

Something that causes a disease, for example bacteria or virus

Question 11

Define immune system

Answer 11

A system of defenses to stop invading pathogens

Question 12

Define immunogenic

Answer 12

Something which induces an immune response in the body

Question 13

Define antigen

Answer 13

A molecule which induces an immune response via a lymphocyte - pathogens show antigens on their surface

Question 14

Define antibody

Answer 14

A molecular component of the immune system that recognises and binds with antigens

Question 15

What is innate immunity?

Answer 15

The defense systems that are always deployed

Question 16

What are the 3 lines of defense? Classify innate and adaptive immunity

Answer 16

First line of defense (innate)

• skin
• secretions
• mucous membranes

Second line of defense (innate)

• phagocytic cells
• natural killer cells
• defensive proteins
• inflammatory response

Third line of defense (adaptive)

• adaptive defenses
• lymphocytes (B and T cells)
• antibodies

Question 17

Which body system is part of the immune system and at which stage does it function?

Answer 17

The lymphatic system is involved in both the second and third line of defense - involved in innate and adaptive immunity

Question 18

How do pathogens enter the body?

Answer 18

Eat, breathe, touch - hence blocked by external defenses first

Question 19

What are external innate defenses?

Answer 19

Bodies first line of defense to invading pathogens

• skin
• secretions
• mucous membranes

Question 20

What are internal innate defenses?

Answer 20

Second line of defense

• phagocytic cells
• natural killer cells
• defensive proteins
• inflammatory response

Question 21

How does the inflammatory response occur?

Answer 21

Histamine is released from injury site

The blood vessel dilates and its permeability increases

This allows blood cells to leave the blood vessels and enter injury site causing redness and swelling

Cells carry out phagocytosis

Virus-infected and cancer cells are killed

Question 22

How does phagocytosis occur?

Answer 22

Phagocytes have receptors that detect pathogens

A phagosome is formed as the bacteria is engulfed

Phagosome binds with lysosomes to form phagolysosomes

Bacteria broken down and soluble debris leaves

Question 23

What is the internal adaptive defenses?

Answer 23

Third line of defense:

B lymphocytes and T lymphocytes

Antibodies

Question 24

Where are B cells produced and what is its function?

Answer 24

Develop and specialise in the bone marrow

They make antibodies

Question 25

Where are T cells produced?

Answer 25

Develop in bone marrow and mature in the thymus

Question 26

How are B and T cells activated?

Answer 26

Specific shapes of receptors detect specific pathogens

Question 27

What are the characteristics of antigens?

Answer 27

1. Immunogenicity - ability to provoke an immune response by stimulating production of antibodies or T cells
2. Reactivity - ability of antigen to react specifically with antibodies or cells it provoked

Question 28

What happens on second exposure to a pathogen?

Answer 28

There would be memory B and T cells in the lymph nodes

These are activated if the body is exposed a second time to the same pathogen

The secondary response is much faster, stronger and lasts longer than the first

(this is how vaccines work)

Question 29

What is serology?

Answer 29

Study involving determination of whether an infection is acute or historical

Question 30

What is a serosurvey?

Answer 30

Collection and blood testing of blood from a defined population to estimate the prevalence of antibodies against an infectious pathogen as an indicator of exposure