Cellular Adaptations

Question 1

Define Atrophy

Answer 1

Reduction of the number and size of cells, tissue and organ thus causes decrease or stopping of function

Question 2

What Physiological atrophy

Answer 2

Physiological= this is a normal process of ageing

1. Atrophy of lymphoid tissue in lymph nodes, appendix and thymus.
2. Atrophy of gonads after menopause.
3. Atrophy of brain.
4. Atrophy of bones.

Pathological= This can be subcategorized as general or local.

General= Oncologic and chronic diseases.
• Starvation.
• Injury of hypophysis (endocrine cachexia).
• Injury of hypothalamus (cerebral cachexia).

Exhaustion
decreased adipose tissue
osteoporosis (weakness of bones)

Question 3

What will you witness Histologically regarding

Answer 3

Cells become smaller but are not dead

Accumulation of lipofuscin around nucleus takes place.
Lipofuscin (“wear and tear”
pigment) is a golden yellow pigment representing undigested lipid material derived from cellular metabolism

Question 4

What is local atrophy

Answer 4

Ischemic
Dysfunctional atrophy
Neuropathic
Endocrine
Pressure
Due to chemical and physical influences
Idiopathic atrophy (Disease whereby the cause is unknown)

Question 5

Define Hypertrophy and Hyperplasia

Answer 5

Hyperplasia= This is an abnormal increase in the amount of parenchymal cells, resulting in enlargement of the organ or tissue

Hypertrophy= This is the increase in size of the parenchymal organ without any changes to the number of cells

These 2 processes usually happen simultaneously

Question 6

List the causes of both hypertrophy and hyperplasia

Answer 6

Physiological factors

Neurohumoral hypertrophy(Neurohumoral activation refers to increased activity of the sympathetic nervous system, renin-angiotensin system, vasopressin and atrial natriuretic peptide. and hormonal production )= Hypertrophy of female breast after puberty or after pregnancy

Working Hypertrophy= of skeletal muscle this can be due to exercise

Pathological Hypertrophy

Neurohumoral= overactivity of oestrogen production will increase male breast

Compensatory reparative hypertrophy= increase in size after partial hepectomy or regeneration of epidermis tissue after injury

Vicarious hypertrophy

hypertrophi

Question 7

Define concentric, eccentic and myogenic dilation

Answer 7

Concentric hypertrophy= this is when the walls of the heart are thickened without any other structures being enlarged

Eccentric hypertrophy= This is when the myocardium is enlarged without the chambers of the heart being dilated and this leads to myogenic dilation

Question 8

Define Metaplasia

Answer 8

This is a reversible change of one type to another type of adult epithelial or mesenchymal cells, usually in response to abnormal stimuli, and often reverts back to normal on removal of stimulus.
There are 2 types A.Epithelial metaplasia
and B.Meesenhymal metaplasia

Question 9

Define Dysplasia

Answer 9

This is the quantity of abnormal cells it is usually accompanied with metaplasia and hyperplasia.
Hyperplasia of epithelial layers.
• Disorderly arrangement of cells from basal layer to the surface layer.
• Cellular and nuclear pleomorphism.
• Increased nucleocytoplasmic ratios.
• Nuclear hyperchromatism.
• Increased mitotic activity.
The two most common examples of dysplastic changes are the uterine cervix and respiratory tract.