Cellular Response to Injury

Cellular Adaptation

How our bodies accommodate and fight against injury and stress

How do all diseases occur on the cellular level

by cellular injury, cellular malfunction and cellular death

simply how does cellular adaptation occur

through gene expression

How can cells change during cellular adaptation?

changed in the size, number and/or type of cell

why does cellular adaptation occur?

it is a stress response that is detected through receptors that detect an environmental stimulus

t/f: the change in the cell is proportional to the stimulus?

true - the change in the cell is proportional to the stimulus

what happens to the cells when the stimulus is removed?

reverse adaptation, “goes back to normal”, BUT NOT ALWAYS

cellular adaptation can be normal and abnormal

yes, normal - physiological abnormal -pathophysiological

Types of cellular adaptation that changes in cell size or number

-Atrophy -Hypertrophy -Hyperplasia

Types of cellular adaptation that changes in cell type

-metaplasia -dysplasia

atrophy

decrease on size

why does atrophy happen

from descreased demand or decreased nutrient supply

hypertrophy

increases in size

why does hypertrophy happen

from increased demand ——> ex. skeletal muscle and cardiac muscle

hyperplasia

increase in number

why does hyperplasia happen

from increased demand ——> ex. skin, intestinal, gland, hepatic, reproductive organ cells (BPH)

metaplasia

from one cell to another

why does metaplasia happen

from chronic irritation or inflammation, and the new cells type is tougher and better able to survive in the changed conditions

example of metaplasia

Barrett’s esophagus / GERD

Is metaplasia reversible?

yes it is reversible

Think about Barrett’s esophagus / GERD and explain why metaplasia happens

food is going from the stomach to the esophagus, so there is cell damage in the esophagus due to the acid, then the esophagus cells change to stomach like cells to withstand the acid.

dysplasia

cells are all messed up

why does dysplasia happen

from chronic irritation or inflammation, and the new cells types are abnormal and DO NOT dunction very well

Is dysplasia different than anaplasia?

yes it is different, because anaplasia is the loss of the mature or specialized features of a cell or tissue and is in malignant tumors —> pre-cancerous cells

anaplasia

is the loss of the mature or specialized features of a cell or tissue and is in malignant tumors —> pre-cancerous cells

What cellular adaptation is this?

atrophy - descrease in cell size because of decreased demand or decreased nutrient supply

What cellular adaptation is this?

hypertrophy - increase in cell size from increased demand —> ex. skeletal muscle and cardiac muscle

What cellular adaptation is this?

hyperplasia - increase in number from increased demand —> ex. skin, intestinal, gland, hepatic, reproductive organ cells (BPH)

What cellular adaptation is this?

metaplasia - from one cell to another, from chronic irritation or inflammation, it is so the new cells type is tougher and avle to survive to the changed conditions, but it is reversible

What cellular adaptation is this?

dysplasia - cells are all messed up, from chronic irritation or inflammation, however the new cell types are abnormal and DO NOT function very well

The nurse is reviewing the report from the bronchoscopy for a newly admitted patient who has smoked for the past 20 years. The report states that the columnar ciliated epithelial tissue of the bronchus has been replaced with stratified squamous epithelial tissue. The change in tissue type resulted from which mechanism.

A. Genetic mutation within the respiratory tract

B. Adaptation to stressors due to environmental irritants

C. A disease process that began in the cells of the respiratory tract

D. Toxins accumulating in the tissue of the lungs

B. Adaptation to stressors due to environmental irritants

A patient is being evaluated for a muscular neurodegenerative disorder. The nurse notes on assessment that the musculature on the left leg is smaller than the musculature on the right leg. How would the nurse document this finding?

A. hypertrophy

B. dystrophy

C. Dysplasia

D. atrophy

D. atrophy - decreases in size

t/f: A person with diabetes may develop hypertrophic cells due to poor circulation

False, because poor circulation doesn’t cause hypertrophy

hypertrophy - increase in size due to increased demand in skeletal or cardiac muscle cells

cellular injury

when a cell is no longer able to maintain homeostasis because there are structural and functional changes.

what are the main mechanisms of cellular inury?

Free radiacal form, hypoxic injury with ATP depletion, and dystrophoic calcification

where can dystophic calcification occur?

heart valves, and brain (basal ganglia, white matter)

hypoxic injury

brain damage caused by insufficient oxygen supply to the brain leading to cell dysfunction and death.

dystrophic calcification

a condition where calcium deposits form in damaged or dead tissue

Why does an free radical create a problem like cellular injury

because it steals a friend - another atom so it gets damaged or injured —> ex. oxidative damage or reperfusion injury —> this is when we have a lot of free radicals

How do antioxidants help cellular injury?

because they have 1 extra electron to give to free radicals —> Ex. Vitamin C, A, D

what is hypoxic injury

low oxygen —> an imbalance between oxygen demand exceeds the oxygen supply.

how does metabolism change with hypoxic injury

metabolism changes from aerobic metabolism (36ATP) to anaerobic metabolism (2ATP)

What are some of the things that happen with hypoxic injury?

lactic acid build up —> lower pH

lower ATP production —>higher intracellular Na & lower intracellular K = water follows solute so the cell swells and possibly dies

what is apoptosis

programmed/planned cell death

how does apoptosis happen?

by removing unwanted cells in an orderly way by releasing endogenous enzymes which break the cell up without signs of inflammation, so then the debris is phagocytized by other cells called phagocytes —> basically cells eat the other cells’ parts so they go bye bye

what is necrosis?

unregulated/unplanned cell death

What happens because of necrosis?

The cell products that are released cause inflammation

they are always pathologic

what does the enzyme p53 do?

It contributes to apoptosis for the intrinsic and extrinsic pathways