0.2 Tissue response to Injury

Question 1

What is necrosis?

Answer 1

Evidence of cell death in a living body

Callular leakage leading to inflammation which removes cellular debris

Question 2

What is coagulative necrosis associated with?

Answer 2

Ischemia (reduced blood flow / lack of oxygen)

Pyknosis, Karyorrhexis, and Karyolysis

Question 3

What is liquefactive necrosis associated with?

Answer 3

Related to microbial growth

Tissue transformed into liquid / viscous mass (microbes eat biological tissue turning stucture into liquid / pus)

Question 4

What is caseous necrosis associated with and how does it visually appear macroscopically and microscopically?

Answer 4

Specific to TB, syphilis, and some fungi

Macroscopically = cheesy tan/white

Microscopically = pink, proteinaceous mass encapsulated by granulomatous processes

Question 5

What is apoptosis?

Answer 5

Programmed cell death

No cell leakage, no inflammation

Question 6

What is acute inflammation?

Answer 6

Coordinated host response to injury

Preprogrammed = similar for all causes

Mostly vascular and local changes

Question 7

What is chronic inflammation?

Answer 7

Next progression, if acute inflammation is unable to deal with bacterial load

Long standing response to long standing injury in which injury and repair occur simultaneously

Different patterns depending on case, but feature emigration of monocytes/lymphocytes into tissues

Question 8

Wound healing can be undertaken by regeneration or repair. What is the difference between them?

Answer 8

Regeneration = replacement of tissue with original tissue eg liver

Repair = blood clot or nectrotic tissue replaced with granulation tissue (matures to scar/bone/adipose)

Question 9

What are the two types of immunity?

Answer 9

1. Non-specific / innate
2. Specific / adaptive

Question 10

What are the characteristics of non-specific / innate immunity?

Answer 10

1. Not targeted to specific organsims
2. Does not increase after first exposure to organism

Question 11

What are the characteristics of specific / adaptive immunity?

Answer 11

1. Targeted to specific organisms
2. Increases following exposure
3. Confers future protection against organism

Question 12

What are the four classical signs of acute inflammation?

Answer 12

1. Swelling
2. Pain
3. Redness
4. Heat

Question 13

The major changes for acute inflammation are vascular to better get blood into tissues with leukocytes and plasma protective factors. How do these changes relate to the classical signs of acute inflammation?

Answer 13

1. Vascular leakage = swelling
2. Limited movement = pain
3. Vasodilation = Redness + heat

Question 14

What are the 3 morphological types of acute inflammation?

Answer 14

1. Suppurative = pus formation
2. Serous = voluminous clear fluid produced
3. Fibrinous = fibrin deposited on a surface

Question 15

Opening of vasculature brings blood to the body surface, which is normally cooler than the core temperature, resulting in redness and heat. What are the steps behind vascular dilation?

Answer 15

1. Increased blood flow = arteriole + venule dilation and the expansion of capillary bed
2. Leads to edema = swelling + leakage of plasma/proteins in ECM
3. Neutrophils emigrate into EM (normally only occasional lymphocytes + macrophages)

Question 16

What are Starling’s forces?

Answer 16

Relationship between hydrostatic and oncotic pressure

Question 17

What is the process behind vascular leakage?

Answer 17

Inflammatory mediators increase endothelial permeability

Protein leaks out, water follows = protein rich exudate / inflammatory oedema

Question 18

Swelling in acute inflammation is caused by increased vascular permeability and vascular leakage. Starling’s forces play a key role in this. Explain how.

Answer 18

1. Net Flow shifts from normal to outward via increased hydrostatic pressure
2. Vessel dilates to accomodate pressure changes
3. Pressure changes allow plasma proteins + water to leak out in rich exudate (oedema)

Question 19

Oedema plays an important role in acute inflammation. What is it?

Answer 19

1. Oedema dilutes toxins and increases lymph flow
2. Lymph flow takes toxins / bacterial products out of area
3. Bacterial antigens + toxins presented to lymph nodes for development of immune response