Reversible Cellular Injury

Question 1

What is the difference between homeostasis, stress, adaptation, disease and failure?

Answer 1

• Homeostasis is the body’s normal set point
• When cells of the body encounter a stressor, that stressor may cause those cells to adapt in order to maintain homeostasis.
• If the stressor is presented for a long enough time and/or with increasing severity, it can lead to disease
• If the stressor remains for a long duration, the adaptations can lead to decreased organ function and failure
• Example: Homeostasis = normal BP, stressors = increased BP due to increased blood volume, adaptation = LV hypertrophy to increase pumping capacity of heart to pump against higher afterload, disease = chronic HTN, failure = stressor sustained for long duration, heart loses pumping capacity, develop heart failure

Question 2

This image shows the model of disease progression. Explain this model.

• What is normal, mild, moderate, severe disease
• What is failure
• Since a person can have disease without symptoms, how would you determine if they have disease?

Answer 2

• Normal = homeostasis
• Stressors force adaptation to new environment to maintain homeostasis, in some cases this can lead to functional changes in the tissue that can cause disease
• Mild, moderate and severe disease are quantified by the amount of stress required to induce failure
• Failure is inability to maintain homeostasis at rest and is symptomatic at rest
• To identify disease when asymptomatic - subject organ in question to stress and see how it performs, or look at the tissue itself (anatomic)

Question 3

Describe the relationship between stress and adaptation.

Answer 3

Question 4

What drives the tissue changes seen in cellular adaptation to a stressor?

Answer 4

Embryologic like changes in the cells

Question 5

What changes are seen at the organ level?

At the cell/tissue level?

Answer 5

Question 6

True/False: Hypertrophy is reversible.

Answer 6

True

Question 7

What is hypertrophy?

Answer 7

An increase in the size of the cells (cellular proteins, cytoplasm, nuclei) that results in an increase in the size of the affected organ.

Question 8

What is lipofuscin?

Answer 8

lipid containing residue of lysosomal degradation. Wear and tear pigment that appears on staining –> indicative of atrophy

Question 9

What is cachexia?

Answer 9

Loss of weight, muscle atrophy, fatigue, weakness, significant loss of appetite in someone who is not actively trying to lose weight. Loss of body mass that cannot be reversed nutritionally.

Question 10

What is metaplasia?

Answer 10