First Lecture

Question 1

Causes of cellular injuries

Answer 1

1. Hypoxia – Ischemia
2. Physical Agents
3. Chemical Agents & Drugs
4. Infectious Agents
 5. Immunologic Reactions 
6. Genetic derangement 
7. Nutritional Imbalance 
8.Ageing

Question 2

Main reasons for hypoxia_ischemia

Answer 2

A- Atherosclerosis & Thrombi
B- Cardiopulmonary failure
C- Loss of oxygen carrying capacity, e.g. pneumonia, anemia, CO poisoning

Question 3

Physical Agents that cause cell injuries

Answer 3

A- Mechanical trauma 
B- Extremes of temperatures 
C- Sudden change in atmospheric pressure 
D- Radiation 
E- Electric Shock

Question 4

Example of Chemical Agents & Drugs that may causes a cell injury

Answer 4

A-Glucose and salts 
B-Oxygen 
C- Heavy Metals 
D- Insecticides 
E- Ethanol
 F-Carbon Monoxide

Question 5

Physiologic Cellular Adaptation to Injury

Answer 5

Normal stimulation by hormones, e.g. enlargement of breasts in pregnancy and lactation

Question 6

Pathologic Cellular Adaptation to Injury

Answer 6

1. Atrophy
2. Hypertrophy
3. Hyperplasia

Question 7

Atrophy defenition

Answer 7

Shrinkage in the size of the cell due to loss of cell substance -> diminished function

Question 8

Causes of atrophy

Answer 8

1. Decreased workload
2. Loss of innervation
3. Decreased blood supply
4. Inadequate nutrition
5. Loss of endocrine stimulation
6. Ageing

Question 9

What is the Autophagy

Answer 9

starved cell eats its own components to find nutrients

Question 10

Cells contain 2 proteolytic systems (enzymes) that result in protein degradation

Answer 10

1- Lysosomes

2- Ubiquitin

Question 11

The degradation of cellular proteins occurs mainly be the

Answer 11

ubiquitin-proteasome pathway

Question 12

What cause activate ubiquitin ligases, and what does it do

Answer 12

Nutrient deficiency and disuse may activate ubiquitin ligases, which attach multiple copies of the small peptide ubiquitin to cellular proteins and target these proteins for degradation in proteasomes.

Question 13

Hypertrophy mean

Answer 13

It is an increase in the size of cells and with such change, an increase in the size of the organ.
- More structural component

Question 14

Example of physiological hypertrophy

Answer 14

The uterus during pregnancy, Muscle building.

Question 15

Example of pathological hypertrophy

Answer 15

Cardiac hypertrophy in hypertension and cardiac valve diseases.

Question 16

The result of atrophy

Answer 16

Decrease in the structural component of the cell. Imbalance between protein synthesis and degradation, .i.e. Decreased synthesis, Increased degradation, or both
Autophagy : starved cell eats its own components to find nutrients

Question 17

The result of hypertrophy

Answer 17

1- The synthesis of more proteins and myofilaments per cell.
2- There may also be a switch of contractile proteins from adult to fetal or neonatal forms.(during muscle hypertrophy, the α-myosin heavy chain is replaced by the β form of the myosin heavy chain, which has a slower, more energetically economical contraction.)

Question 18

Hyperplasia mean

Answer 18

It is an increase in the number of cells in an organ or tissue

Question 19

Cells are divided into 3 types depending on their ability to divide

Answer 19

1- Cells with high capacity for hyperplastic growth (labile cells)
e.g. hematopoietic cells in bone marrow, epidermis, intestinal epithelium, exocrine duct epithelia, and transitional epithelia of the urinary bladder.
2- Cells with low capacity (permanent cells)
E.g. Nerves and cardiac muscle cells
3- Cells with intermediate capacity (stable cells)
E.g. Cartilage and smooth muscle cells

Question 20

Hyperplasia can be divided into

Answer 20

1- Physiologic : A. Hormonal hyperplasia (breast, uterus) B. Compensatory hyperplasia (liver) 2- Pathologic : A. Excessive hormonal stimulation (endometrial hyperplasia) B. Effects of growth factors on target cells. (Stimulation by growth factors, wound healing, viral infections