Cell Adaptation

Question 1

Summarize cell adaptation to non lethal injury

Answer 1

1. Alteration in size
   - Atrophy
   
   • Decrease in size of existing cells
     - Hypertrophy
   • Increase in size of existing cells
2. Increase in number
   
   • Hyperplasia
3. Change in differentiation
   - Metaplasia

Question 2

How does a myocyte respond to stress and injury?

Answer 2

Adaptation: response to increased load, adapted myocytes (hypertrophy)

Reversible injured myocytes leads to cell death

Question 3

What are the early cellular responses to injury?

Answer 3

• Mild damage to cell components
• Cell degeneration
• Reversible

1. Cloudy swelling
   - Earliest evidence of injury.
   - Loss of normal staining intensity due to swelling of organelles
2. Hydropic degeneration
   - Continued swelling of organelles
   - Vacuoles appear in cytoplasm
   
   • Stains faintly with basophilia
3. Fatty change (steatosis)
   - Accumulation of triglycerides in cytoplasm
   - Most common in liver-rarely in cardiac & skeketal muscle

Common causes

• Toxins
  
  • Alcohol
• Chronic hypoxia

Question 4

What are the causes and effects of hypertrophy?

Answer 4

Increase in size of cells which can result in increased in size of organ

• Reversible
• No change in cell number

Cause

• increased functional demand
• Specific hormonal stimulation

Question 5

What tissues are commonly affected by hypertrophy?

Answer 5

Cardiac muscle

• increased demand
  
  • hypertension
• Skeletal muscle
  
  • Increased workload
    
    • Exercise
• Uterus
  
  • Hormonal
    
    • pregnancy

Question 6

What are the causes and effects of atrophy?

Answer 6

Reduction in functional cell mass

• decreased size & function of cells
• reversible

Cause:

• decreased functional demand
• Decreased blood supply
• loss of innervation
• Loss of endocrine stimulation
• Nutritional deficiency
• Aging

Question 7

What tissues are commonly affected by atrophy?

Answer 7

-Testis in elderly

• Skeletal muscle
  
  • Disuse
  • Loss of innervation

Brain

• neuridegenerative
• aging

Question 8

What are the causes and effects of hyperplasia?

Answer 8

Increase in number of cells(reversible)

Causes

• increased functional demand
• Hormonal stimulation

Question 9

What is compensatory hyperplasia?

Answer 9

Increase in tissue mass after damage or partial restriction (Ex. Liver)

Question 10

What tissues are commonly affected by hyperplasia?

Answer 10

• Endometrium
  
  • Hormonal stimulation

Prostate gland
-Hormonal stimulation

Red blood cells
-High altitude

Glandular epithelium of breast
-hormonal stimulation

Uterine enlargement
-Pregnancy

Question 11

What are the causes and effects of metaplasia?

Answer 11

Change in cell differentiation

• Reversible
• One differentiated cell type is replaced by another differentiated cell type
  
  • Reprogrammed stem cells

Cause:

• Adaptive response to environmental stimuli
  
  • Cigarrete smoke
  • Acid reflux

Question 12

What tissues are commonly affected by metaplasia?

Answer 12

• respiratory epithelium
• Cervical epithelium
• Esophageal epithelium

Question 13

Metaplasia leads to…

Answer 13

Increased risk for dysplasia and neoplasia

Question 14

What are the causes and effects of dysplasia?

Answer 14

Failure of differentiation and maturation

• cellular atypia
  
  • structurally abnormal
• High nuclear to cytoplasm ratio
• Large nuclei with dark staining chromatin

Cause:

• Rapid multiplication of cells
• May demonstrate genetic abnormalities

Question 15

What tissues are affected by dysplasia?

Answer 15

Cervix, skin

Question 16

Dysplasia May come from …

Answer 16

Tissue With Metaplasia

May also increase risk of neoplasia

Question 17

What are the two main groups of neoplasia?

Answer 17

1. Benign -grows slowly, remain localized to site of origin

2. Malignant - grows rapidly, invasion & metastasis

Question 18

What is neoplasia?

Answer 18

Neoplasm-abnormal mass of cells

• Cellular proliferation and growth in the absence of an external stimulus
• Variable states of differentiation

Question 19

Contrast the behavior of benign and malignant neoplasms

Answer 19

Benign-expansile growth only; grows only. Often encapsulated

Malignant- expansive, invasive, May metastatise, not encapsulated

Question 20

Describe the histology of benign neoplasm

Answer 20

• resembles cell of origin (well differentiated)
• few mitosis
• Normal or slight increase ratio of nucleus to cytoplasm
• Cells are uniform throughout the tumor

Question 21

Describe the histology of malignant neoplasm

Answer 21

• May show failure of cellular differentiation
• Many mitoses, some of which are abnormal forms
• High nuclear to cytoplasmic ratio
• Cells vary in shape and size (cellular pleomorphism) and/or nuclei vary in shape and size (nuclear pleomorphism)

Question 22

Describe carcinoma in situ

Answer 22

EpitheliaL tissue shows features of carcinoma without a breach of basement membrane

• Structural abnormalities
• Cell crowding
• Pleomorphisms
• Increased & abnormal mitotic activity

May become invasive if left untreated