Lecture 4

Question 1

What are the 9 methods through which microorganisms can injure the host?

Answer 1

Exotoxins, Endotoxin, Other cellwall fragments, Hydrolytic enzymes, Inhibition of secretory products, Invasion and intracellular multiplication, Induction of autoantibodies, Mutation, Obstruction

Question 2

What are the 5 ways in which exotoxins can damage cells? give an example for each

Answer 2

Secretion of electrolytes (as in cholrea)
Necrosis (Leukocidin from staphylococcus aureus)
Apoptosis (programmed cell death caused by shiga toxins)
Nerve synapse inhibition (tetanus)
Super antigens (trigger cytokine release resulting in toxic shock)

Question 3

How can endotoxins from gram negative bacteria damage the host?

Answer 3

Lipopolysaccharide in cell wall of gram negative bacteria initiates inflammation cascade

Question 4

How can cell walls of gram positive bacteria damage hosts?

Answer 4

Lipotechoic acid begins an inflammation cascade

Question 5

What is the purpose of hydrolytic enzymes?

Answer 5

Allows bacterial spread through out tissues

Question 6

Give an example of inhibition of secretory products causing harm

Answer 6

Inhibition of stomach acid or digestive enzymes

Question 7

How is invasion and intracellular multiplication damaging?

Answer 7

Viruses enter the cell and cause them to lyse at the end of their reproductive cycle

Question 8

What is induction of autoantibodies?

Answer 8

When microbes have antigens similar to the host which results in an autoimmune attack

Question 9

What damage can be caused by mutations from viruses?

Answer 9

Viruses can integrate with host DNA an introduce things such as oncogenes

Question 10

What are the two ways in which the immune system responds to threats?

Answer 10

Inflammation (non-specific), immune responses (specific)

Question 11

What are the 5 signs of inflammation?

Answer 11

Redness, swelling, heat, pain, loss of function

Question 12

What is a suppuration?

Answer 12

inflammation in solid tisssue with a pyogenic casual agent

Question 13

What is pyrexia

Answer 13

fever

Question 14

What is an abcess?

Answer 14

An inflammation occurring in the fibroblastic boundry with a pus filled centre

Question 15

What is an Ulcer?

Answer 15

A lesion caused by inflammation in the epithelia

Question 16

What is cellulitis?

Answer 16

An inflammation which is in connective tissue

Question 17

What is the process of inflammation?

Answer 17

Mediators are released from activated cells and plasma
These mediators result in vasodilation and increased permeablilty causing an abnormal increase in blood flow
This causes redness and heat
Leukocytes migrate to the site of infection as a result of chemotaxis

Question 18

What is hyperaemia?

Answer 18

The increase in blood flow caused by the inflammation response

Question 19

What are the effects of inflammation?

Answer 19

Pyrexia, Leukocytosis, Acute phase proteins, Endocrine changes

Question 20

What causes pyrexia?

Answer 20

Cytokines such as interleukin-1 from monocytes and macrophages

Question 21

What is leukocytosis?

Answer 21

Increased production and release of neutrophils and monocytes

Question 22

What are acute phase proteins?

Answer 22

Proteins who act to limit the damage of infections and resolve them, they have increased production during the inflammatory response

Question 23

What are the endocrine changes seen during infection?

Answer 23

Increased production of glucocorticoid steroids

Question 24

What is a primary lymphoid organ? And name two

Answer 24

An organ which produces lymphocytes such as the thymus and bone marrow

Question 25

What is a secondary lymphoid organ?

Answer 25

Where mature lymphocytes migrate to and are predominately found, their key role is to filter out foreign matter

Question 26

What proportion of your lymphocytes are in your bloodstream?

Answer 26

10%

Question 27

What are the two major functions of the lymphatic system?

Answer 27

To transport material such as antigens to secondary lymphoid organs in order to generate an immune response
To return fluid from the tissues and return it to the bloodstream

Question 28

What is antigen presenting cell?

Answer 28

A cell which takes material from a microorgansim and transfers it to the nearest secondary lymphoid organ