Week 2 Tissue

Question 1

3. Hyperplasia

Answer 1

3. Hyperplasia - increase in number of cells in an organ or tissue

Question 2

Organelles

Answer 2

	Endoplasmic reticulum
	Golgi apparatus
	Lysosome
	Peroxisome
	Mitochondria

Question 3

Cellular Functions

Answer 3

1. Transportation  passive and active
2. Ingestion  endocytosis
3. Secretion  exocytosis
4. Respiration  aerobic and anaerobic production of ATP
5. Communication  direct cell-to-cell or hormonal
6. Reproduction  mitosis and meiosis

Question 4

Homeostasis

Answer 4

Homeostasis
Maintenance of a relatively stable internal environment
•	Includes:
	Temperature
	Blood pressure 
	Blood pH, glucose, electrolytes
	O2

Question 5

Cell Stressors include:

Answer 5

• Infection – microbial agents
• Physical agents – trauma, electrical, temperature
• Radiation – ionizing, nonionizing, UV
• Chemicals – acid, alkali, toxins
• drugs, lead, CO, ethanol, mercury
• Nutritional – excesses or deficiencies
• Ischemia / infarction – lack of blood supply
• Immune reaction – auto, allo, allergy
• Genetic and metabolic disorders

Question 6

Cellular Response to Stress

Answer 6

1. Atrophy
2. Hypertrophy
3. Hyperplasia
4. Metaplasia
5. Dysplasia
6. Anaplasia
7. Intercellular accumulations and storage of products in abnormal amounts

Question 7

Atrophy

Answer 7

• decrease in size of a cell

• Results in decreased functional capability and size

Question 8

Atrophy causes include

Answer 8

• Decreases in workload / use
• Decreases in blood supply (hypoxic / ischemic)
• Decreases in nutrition (protein)
• Decreases in hormonal stimulation – testosterone decrease
• Decreases in nervous system stimulation
• Old age –

Question 9

Hypertrophy

Answer 9

increase in cell size
• The increase in size includes an increase in cellular components needed to increase cell function to adapt to work demands
• There is a limit to hypertrophy whereby further increase in tissue mass can no longer compensate for increased demands

Question 10

Physiological (“normal” or “good”) hypertrophy:

Answer 10

 Caused by an increase in workload (skeletal and cardiac muscle with exercise) or hormonal stimulation (breasts during pregnancy)

Question 11

• Pathological hypertrophy (“abnormal” or “bad”)



Answer 11

 Adaptive – myocardial hypertrophy caused by hypertension

 Compensatory – enlargement of cells of remaining kidney if other kidney is removed

Question 12

Hyperplasia

Answer 12

3. Hyperplasia - increase in number of cells in an organ or tissue
   • Occurs with increased workload or hormonal stimulus
   • Only occurs in tissues with cells that are mitotic
   • ex: epidermal cells, glandular cells, intestinal epithelium
   • Often occurs with hypertrophy

Question 13

• Examples of hyperplasia:

Answer 13

 Hormonal hyperplasia – Compensatory hyperplasia – Pathologic hyperplasia –
 Physiologic hyperplasia

Question 14

 Hormonal hyperplasia –

Answer 14

breast and uterine enlargement during pregnancy are due to estrogen stimulation

Question 15

 Compensatory hyperplasia

Answer 15

the regeneration of the liver after partial removal

Question 16

 Pathologic hyperplasia –

Answer 16

excessive estrogen production can lead to endometrial hyperplasia and abnormal menstrual bleeding

Question 17

4. Metaplasia -

Answer 17

reversible change in which one adult cell type is replaced by another adult cell type within same primary tissue group (epithelial, connective tissue)
• Allows for substitution of cells that are better able to survive the conditions

Question 18

 Pathologic metaplasia –

Answer 18

change from ciliated columnar epithelium to stratified squamous epithelium in the airways of a smoker

Question 19

Dysplasia -

Answer 19

deranged cell growth that leads to changes in size, shape and appearance
• This adaptation serves no specific function, but may be reversible if irritating stimulus is removed
• Some dysplasia can appear due to chronic irritation or inflammation
 Thought to be a precursor to cancer

Question 20

Intracellular Accumulations -

Answer 20

buildup of substances that cells cannot immediate used or dispose of
• Can be toxic or harmless, some permanently or temporarily accumulated

Question 21

• Intracellular accumulations include -



Answer 21

 Normal substances – lipids, carbohydrates, bilirubin – that are present in abnormal amounts
 Abnormal endogenous products, such as those resulting from errors of metabolism (ex: free radicals)
 Exogenous products, such as environmental agents that cannot be broken down by the cell

Question 22

• Causes of cell stress and injury

Answer 22

• Infection – microbial agents
• Physical agents – trauma, electrical, temperature
• Radiation – ionizing, nonionizing, UV
• Chemicals – acid, alkali, toxins
• drugs, lead, CO, ethanol, mercury
• Nutritional – excesses or deficiencies
• Ischemia/Infarction – lack of blood supply
• Immune reaction – auto, allo, allergy
• Genetic and metabolic disorders

Question 23

• Three main mechanisms of cell injury are

Answer 23

 Free radical injury
 Hypoxic injury causing ATP depletion and altered membrane permeability
 Impaired Ca2+ homeostasis

Question 24

Free radical injury

Answer 24

• Free radicals (oxidants) are highly reactive chemical species
• Mechanism of injury:
 damage of cell membrane, inactivation of enzymes, or damage to DNA
 Defenses against some free radicals are vitamins C and E and beta-carotene (anti-oxidants)

Question 25

Hypoxic cell injury causing ATP depletion

Answer 25

• Cells suffer from a lack of oxygen, which interrupts production of ATP • Well-differentiated cells, such as brain and heart, require large amounts of oxygen; brain cells undergo permanent damage after 4 to 6 minutes of oxygen deprivation • Mechanism of injury:  ATP depletion -> shut down of Na+K+ pump and NCX  rise in [Na+]i and [Ca2+]i -> cell swelling and Ca2+ damage -> eventual membrane damage

Question 26

• Causes of hypoxia

Answer 26

• Decreased:  O2 supply (ex: drowning)  transport of O2 across lung surfaces (ex: pneumonia)  transport of O2 (ex: anemia, CO poisoning)  hypoxemia  delivery of O2 (ex: ischemia)  ability of cell to use O2 for cell respiration (ex: cyanide)

Question 27

Impaired Ca2+ Homeostasis

Answer 27

Both free radial injury and hypoxic injury both lead to altered membrane permeability (especially for Na+) and Ca2+ imbalances • Normally, [Ca2+]i is extremely low • Calcium can activate enzymes within the cell that could lead to damage • Phospholipases can break down cell membranes • Proteases to damage DNA and mitochondria

Question 28

Cell Death

Answer 28

• Occurs either by apoptosis or necrosis

Question 29

• Apoptosis

Answer 29

* Apoptosis is controlled (programmed) cell death and is involved in normal cell deletion and renewal * occurs when cells are in excess, damaged or aged * ex. embryonic development of heart, separation of webbed fingers and toes, virus-infected cells

Question 30

• Necrosis is a

Answer 30

* Necrosis is a pathologic form of cell death resulting from cell injury * Cell swelling->  damage to mitochondria and eventual rupture of the cell membrane -> unregulated enzymatic digestion of cell