Week 3- Cell adaptations + damage

Question 1

What is cell adaptation? When may it happen & what can change to preserve cell vitality?

Answer 1

Reversible change in cells in response to environment

Stimuli may arise under physiological or pathological conditions

Cell number

Cell size

Cell type

Question 2

What are the three classes of proliferative cells? Give examples

Answer 2

1) Labile
eg: skin, epithelial
2) Stable
eg: bone
3) Permanent
eg: brain

Question 3

What are the different types of cell adaptation?

Answer 3

Hyperplasia

Hypertrophic

Meterplasia

Atrophy

Question 4

Define Hyperplasia. What is the cell type? Give examples of physiological & pathological hyperplasia including causes

Answer 4

Increase in cell number

Labile/ stable cells

Physiologically:

1) Hormonal → Endometrium
2) Compensatory → Partial hepatcetomy

Pathologically:

• Excessive growth hormone
• Chronic irritation

Can occur alongside hypertrophy

Increased risk of tumour development

Question 5

Define Hypertrophy. What cells can it occur in? Give examples of physiological & pathological hypertrophy including causes

Answer 5

Increase in cell size. More cellular structural proteins

All cells, most common: permanent cells

Physiologically:

1) Increased functional demand → Skeletal muscle
2) Hormonal/ growth factor → Uterine muscle pregnancy

Alongside hyperplasia

Pathologically:

Increased functional demand → Cardiac muscle (LV hypertrophy/ aortic stenosis)

Question 6

Define Atrophy. What are the causes of atrophy?

Answer 6

Shrinkage in cell size with self-digestion of organelles

1) Reduced workload
2) Loss nerve supply
3) Blood supply loss
4) Inadequete nutrition
5) Loss endocrine stimulation
6) Ageing

Question 7

Define Metaplasia. Talk about it- why it happens, what can happen, what it usually involves. Give examples of physiological & pathological metaplasia

Answer 7

Change in cell type from adult cell to another

Talk:

New cell type better adapted to the stimulus

Ground for the later development of cancer

Usually involves epithelium

Physiological:

1) Growth/ development → Glandular to squarmous eputhelium in pubertal cervix

Pathological:

1) Abnormal environemnt → Squarmous to glandular epithlium in GORD

Question 8

What are the different types of developmental abnormalities?

Answer 8

Agenesis: Failure to form

Aplasia: Failure to differentiate into organ specific tissue

Dysgenesis: Failure of tissue to strucurally organise themselves into organ

Hypoplasia: Failure of organ to grow to full size

Question 9

What are the types of abnormal growth?

Answer 9

Dysplasia

Neoplasia

Question 10

What is dysplasia? Talk about it. Where can it occur?

Answer 10

Presence of cellular atypia, increased cell growth, altered differentiation premelignant condition

Ocurrs:

• Cervix
• Bladder
• Stomach/ oesophagus

Question 11

What is Neoplasia? What are the types?

Answer 11

Abnormal growth of cells which persists after stimulus removed and has escaped normally regularatory processes

Benign

Malignant

Question 12

What is cell injury caused by? Is it reversible?

Answer 12

Inhrently injurous stimuli OR when the cell adaptability is exceeded.

Reversible if stimuli is removed, damage is minor + tx given

Question 13

What are the causes of cell injury/death?

Answer 13

GINPIOC

Genetic derrangements

Infectious agents

Nutritional imbalance

Physical agents

Immune response

Oxygen deprivation

Chemicals/ toxins

Question 14

What are the two types of cell death?

Answer 14

Apoptosis → Programmed

Necrosis → Unprogrammed

Question 15

Talk about Cell Death Necrosis:

(6)

What type of cell death?

What are the causes?

What happens to the cell?

Answer 15

Pathological cell death- external factors

Hypoxia, Chemical toxins

Damage to cell physiology

Degredation of cell strucutre

Influx of ions & water

Cellular organelles swell & rupture

Question 16

What is Cell Death by Apoptosis?

Answer 16

Programmed or Physiological

Constituent genes –> Cell death

Question 17

What are the Morphological feature of Necrosis?

Answer 17

Cell membrane integrity is lost & lysosomal hydrolase are released resulting in:

• Small condensed nuclei
• Deeply stained nuclei
• Nuclei fragments in particles
• Cytoplasm becomes deeply stained
• Typically affects a large group of cells
• Enzymatic digestion of cellular contents possible- may leak out
• Frequent adjacent inflammation
• Plasma membrane disrupted

Question 18

What are the Morphological Feature of Apoptosis?

Answer 18

• Organelles remain intact
• Nucleus and cytoplasm condense to form apoptotic bodies
• Intact membranes surrounding apoptotic bodies
• Apoptotic bodies phagocytosed by macrophages
• No inflammatory response
• Typically affects isolated cells

Question 19

What are the types of Necrosis?

Answer 19

Liquefactive

Fat Necrosis

Caseous

Coagulative

Gangrenous

Fibrinoid

Question 20

What is Liquefactive Cell Necrosis?

Answer 20

Tissue is replaced by liquefied material

Accompanied with enzymatic digestion of the tissues

Question 21

What is Fat necrosis Cell Necrosis?

Answer 21

Enzymatic digestions of tissue

Question 22

What is Caseous Cell Necrosis?

Answer 22

Dead tissue looks like cottage cheese (seen in TB infections)

[Midway in appearance between liquefactive & Coagulative]

Question 23

What is Coagulative Cell Necrosis?

Answer 23

• Cells are non-vital i.e. the nucleus is not identifiable but the structure of the tissue still visible histologically
• Reflects cell death WITHOUT enzymatic digestion of the tissues
• Commonly seen in ischaemic injuries (except in the brain)

Question 24

What are the mechanisms of cell damage?

Answer 24

• Free Radicals
• Loss of calcium homeostasis
• Oxidative stress
• Defects in membrane permeability
• Depletion of ATP
• Mitochondrial damage

Question 25

What is infarction?

Answer 25

Area of ischeamic necrosis in tissue/ organ due to reduced/ absent blood supply