Cell pathology 1- Cell injury

Question 1

8 causes of cell injury

Answer 1

1.Immunological reactions

2. Genetic defects
3. Oxygen deprivation
4. Physical Agents
5. Aging
6. Nutritional imbalances
7. Infectious Agents
8. Chemical Agents

(I GO PANIC)

Question 2

What does the cellular response to injury depends on:

Answer 2

Type of injury

Duration

Severity

Question 3

Consequences of an injurious stimulus depends on (4)

Answer 3

Type of cell (e.g. brain and heart need lots of oxygen whereas bone and fat are more resistant to hypoxia)

Status

Adaptability

Genetic makeup

Question 4

What are 4 intracellular mechanisms are vulnerable to cell injury?

Answer 4

Cell membrane integrity

ATP generation - important in maintaining cell integrity

Protein synthesis - affect cell membrane

Integrity of the genetic apparatus - if damaged there could be a malfunction in protein synthesis

Question 5

What 6 cell adaptation to injury are there?

Answer 5

Atrophy
Hypertrohy
hyperplasia
metaplasia
dysplasia
apoptosis

Question 6

Describe Atrophy

Answer 6

shrinking in the size of the cell or organ by the loss of cell substance

Question 7

Describe Hypertrohy

Answer 7

increase in the size of cells and, consequently, an increase in the size of the organ

can be pathological or physiological

Question 8

Describe hyperplasia

Answer 8

increase in the NUMBER of cells in an organ

Can be physiological or pathological

Physiological Hyperplasia: hormonal or compensatory

Hormonal - oestrogenic wave of proliferation of the endometrium

Compensatory - if some tissue is lost

Question 9

Describe metaplasia

Answer 9

a reversible change in which one adult cell type is replaced by another

Question 10

Describe dysplasia

Answer 10

precancerous cells which show the genetic and cytological features of malignancy but not invading the underlying tissue

Dysplasia means that it hasn’t invaded the basal lamina

Cervical cancer screening - aims to identify cells in the dysplastic stage

Question 11

Describe apoptosis

Answer 11

Programmed Death of SINGLE CELLS

Causes:
Embryogenesis - intestines have a lumen because of apoptosis during development

Deletion of auto-reactive T cells in the thymus

Hormone dependent physiological involution - e.g. shedding of endometrium

Cell deletion in proliferating populations

A variety of mild injurious stimuli that cause irreparable DNA damage that triggers cell suicide pathways

Question 12

Differences between apoptosis and necrosis

Answer 12

Apoptosis may be physiological

Apoptosis is an active energy dependent process

Apoptosis is NOT associated with inflammation

Question 13

What are the light microscope changes associated with reversible injury

Answer 13

Fatty change

Cellular swelling

Question 14

What are the light microscope changes associated with non-reversible injury (4)

Answer 14

Coagulative Necrosis-
The substance changes but the shape of the molecule DOES NOT change
the tissue retains the same structure but the nuclei have all gone
The cells in between are inflammatory cells

Liquefactive Necrosis
The brain has totally liquefied
It is an empty space - can only identify cells by looking at the cells around the cyst

Caseous Necrosis-
‘Cheesy’ necrosis
Associated with Pulmonary TB
The necrotic area is GRANULAR which makes it caseous

Fat Necrosis
Associated with ACUTE PANCREATITIS
Acute pancreatitis - you get release of lipases which digests the fat and hydrolyses triglycerides to free fatty acids and glycerol
The free fatty acids combine with calcium in the extracellular fluid and deposits
Each of the deposits (white parts) are areas of fat necrosis

Question 15

What is an ulcer

Answer 15

a local defect, or excavation of the surface, of an organ or tissue, produced by sloughing of necrotic inflammatory tissue

Question 16

Define subleathal injury

Answer 16

• produce injury not amounting to cell death, may be reversible or progress to cell death