Cell injury and cell death

Skin, vagina, cervix, oral cavity, endocrine ducts, and GI tract

What tissue have the proliferative capacity that is continuously dividing

Endothelial cells, Fibroblasts, smooth muscle, and Most solid organs (liver, pancreas, and kidney)

What tissues have the proliferative capacity that is stable

Neurons, cardiac muscle and skeletal muscle

What tissues have proliferative capacity that is permanent

Tissues only divides in response to injury

What does it mean to have a stable proliferative capacity?

No proliferation after birth

What does it meant to have permanent proliferative capacity

Endogenous and exogenous

What are the two main causes of cell stress on injury

Hypoxia, Autoimmune reaction, genetic abnormalities, and Aging

What are examples of endogenous causes of cell stress or injury

Toxins, pathogens, nutritional imbalance, trauma

What are examples of exogenous casued of cell stress or injury

The increase in size of cell

What is hypertrophy

The increase in number of cells

What is hyper plasma

Decrease in cell size

What is atrophy

When a cell type is replace by another cell type that can handle stress better

What is metaplasia?

In cells that have limited capacity to divide

Where can hypertrophy occur

In tissue that is capable of division

Where does hyperplasia occur

Developmental hormones, Compensatory, or pathologic excessive hormonal stimulation

What factors can induce hyperplasia

Hyperplasia is controlled where as neoplasia is unregulated

What is the difference between hyperplasia and neoplasia

Cells reduce their protein synthesis which causes loss of cell substance

How does atrophy occur

Decreased workload, limited blood supply, limited nutrients, loss of endocrine stimulation, and aging

What causes atrophy

Disordered cell growth, proliferation of precancerous cells

What is dysplasia

Possibly

Can dysplasia be reversed

Possibly, not always

Can dysplasia develop into cancer

Failure of cell production during embryogenesis, missing structure

What is Aplasia

Decrease in cell production during embryogenesis, smaller than normal structure

What is hypoplasia

Hypertrophy, hyperplasia, atrophy, metaplasia

What are the main cellular adaptions to stress

Loss of blood flow

What is ischemia

3-5 min

How long can neuron tolerate lack of blood flow without injury

1-2 hours

How long can myocardial cells tolerate lack of blood flow with out injury

Hours

How long can skeletal muscle cells with lack of blood flow without injury

Lack of breathing or ischemia

What can cause hypoxia

Failure of metabolic pathways leading to cell death

What are the effects of hypoxia

Cell damaged cause by reactive oxygen species (ROS)

What is oxidative stress

Nucleic acid, cellular protein and lipids

What does ROS attack

Neutrophils and macrophages

What cells produce ROS

Respiration and energy generation

Where can a small amount of ROS be produced

Absorption of UV/ X-rays, metabolism of chemicals, and inflammation

Where can ROS accumulate

Molecules that help remove ROS

What are free radial scavengers

Superoxide dismutase, glutathione peroxidases, and catalase

What are examples of free radical scavengers

Molecules that block the formation of free radials

What are antioxidants

Vitamin A, C, E and beta-carotene

What are examples of antioxidants

Berries and spinach

What foods are rich with antioxidants

Membrane and DNA damage and protein cross linking

What damage can ROS do

Cellular swelling

What does reversible cell injury consist of

Loss of mitochondrial function, loss of structure/function of membrane, loss of DNA and chromatin structure

What re the 3 main causes of irreversible cell injury

When the nucleus is condensed

What is pyknosis

When the nucleus breaks up in to small fragments (fragmentation)

What is karyorrhexis

When the cell no longer has a nucleus (dissolution)

What is karyolysis

When cellular membranes fall apart and cellular enzymes leak out and digest the cell

What is necrosis

Inflammatory response

What causes necrosis

An infarct in solid organ

What is coagulative necrosis

The brain

Where does coagulative necrosis NOT occur

Tissue looks firm

What is the gross appearance of coagulative necrosis

Cell out lives preserved but no nucleus (eosinophilic)

What are the histologic features of coagulative necrosis

Necrosis causes dissolution of tissue into viscous liquid

What is liquefactive necrosis

Bacterial/fungal infection or hypoxia in CNS

What causes Liquefactive necrosis

Coagulative necrosis that resembles mummified tissue and can have superimposed liquefactive necrosis

What is gangrenous necrosis

Ischemia of a limb

What causes gangrenous necrosis

Necrosis that appears cheese like friable yellow/white tissue

What is caseous necrosis

Tuberculosis infection, body tries to wall off infection

What casues caseous necrosis

Caseating granulomas

What is a major histiological feature of caseous necrosis

Group of macrophages

What is a granulomas

Infection, inflammation, foreign materials

What can casue granulomas

Granulomas surround area of necrosis

What is caseating granulomas

Necrosis that appears like chalky, white deposits in fat

What is fat necrosis

Lipase breaks down fat cells and calcium accumulates

What is the cause of fat necrosis

Pancreatitis

What condition can fat necrosis be found in

Eosinophilic pink deposits in the wall of blood vessels

What is fibrinoid necrosis

Immune-mediated and hypertension

What is the casue of fibrinoid necrosis

Cell shrinks, nucleus condenses and fragments, bless of cells separate from cell and is then digested by macrophage

What is the process of apoptosis

NO

Does apoptosis cause an inflammatory reaction