Patho test

What is apoptosis?

Programmed cell death

When may apoptosis increase?

When cell growth is abnormal, cell numbers are excessive, or cells are injured

How does apoptosis occur?

Cells self-destruct, appearing to digest themselves enzymatically, and then disintegrate

What is the most common cause of cell injury?

Ischemia

What is ischemia?

loss of blood supply which leads to lack of oxygen to tissues/organs

What does ischemia result in?

Insufficient oxygen reaching cells

How can ischemia occur?

Locally- blocked artery; systemically; respiratory impairment

Which organs require especially large quantities of oxygen?

brain, heart, kidneys

What is hypoxia?

lack of oxygen to body tissues

What happens to cellular metabolism during hypoxia?

it decreases, not enough oxygen for normal energy production

What is the purpose of cellular metabolism?

to produce ATP

What happens when ATP production decreases significantly?

The Na+ pump at the cell membrane fails

What happens when the Na+ (sodium) pump fails?

Na+ enters the cell with water which causes cell to swell and possibly rupture

What happens during anaerobic metabolism?

Cells produce energy w/o oxygen, resulting in lactic acid

Why is lactic acid harmful?

It contributes to cellular damage

What physical agents can cause cell injury?

Excessive heat, cold, and radiation

How can heat and cold cause cell injury

they damage blood supply and affect cellular metabolism

How can radiation cause cell injury?

It can disrupt blood flow, change chemicals in cells, damage DNA

What is mechanical damage

pressure or tearing of tissues/cells

How do chemical toxins cause cell injury?

they alter cell membrane permeability or produce reactive chemicals

What are examples of microorganisms that cause cell injury?

Bacteria, viruses, parasites

abnormal metabolites accumulate in cells due to what 2 types of abnormal processes?

inherited- genetic defects; acquired-metabolic abnormalities

How can nutritional deficits cause cell injury?

they interfere with cellular metabolism

imbalance of what 2 electrolytes can lead to cell damage?

K+ or Na+ (potassium or sodium)

What happens during primary cell damage?

Metabolism is altered- loss of cell function

What is reversible cell damage?

If cause of injury is removed quickly, cell could recover

What happens as the amount of cell damage increases?

strucuture and appearance change

What are common changes associated with cell death?

Cell swelling, rupture, lipid build up, damage to cell structures.

What happens to the nucleus after cell death?

It disintegrates

What is cell lysis?

Dissolution or rupture of a cell, releasing its contents

Why does cell lysis cause inflammation?

It releases destructive lysosomal enzymes which causes inflammation and damage to nearby cells

What is necrosis?

process of cell death caused by injury

What are the major types of necrosis? (6)

Liquefactive, coagulative, fat, caseous, fibrinoid, gangrene

What is liquefactive necrosis?

when dead cells are broken down and liquefy due to digestive enzymes

Where is liquefactive necrosis commonly seen?

The brain ( brain infarcts), bacterial infections

What is an infarction?

area of dead tissue due to lack of blood flow and oxygen

What is the gross of liquefactive necrosis?

Liquid, creamy-yellow tissue (pus)

What is the microscopic appearance of liquefactive necrosis?

Many neutrophils and cell debris

Why does bacterial infection cause liquefactive necrosis?

Neutrophils release enzymes that digest dead tissue

What happens in coagulative necrosis?

dead cell proteins become altered or denatured, but cell retains some structure

What commonly causes coagulative necrosis?

loss of blood supply leading to lack of oxygen (ischemia)

Where is coagulative necrosis commonly seen?

In any infarction except the brain

What is the gross of coagulative necrosis?

Firm tissue

What is the microscopic appearance of coagulative necrosis?

Cell outlines look ghostly, red

What is an example of coagulative necrosis?

Myocardial infarction (MI)

What is fat necrosis?

Breakdown of fatty tissue into fatty acids, often due to infection or release of enzymes such as lipase

What condition is commonly associated with fat necrosis?

Acute pancreatitis

Why can fat necrosis increase inflammation?

Free fatty acids can trigger inflammation

What causes the chalky-white appearance in fat necrosis?

fatty acids combining with calcium

What is the microscopic appearance of fat necrosis?

Shadowy outlines, sometimes bluish

What is the key association for fat necrosis?

Acute pancreatitis

Caseous necrosis is a type of _____

coagulative necrosis

caseous necrosis

affected areas look thick, yellow, cheese-like

What disease is classically associated with caseous necrosis?

Tuberculosis

Where is caseous necrosis found in Tuberculosis?

Inside a granuloma

What is a granuloma?

A small solid mass of macrophages and lymphocytes (often covered by connective tissue, which forms in some types of chronic inflammation.

What is the key association for caseous necrosis?

Tuberculosis

Where is fibrinoid necrosis commonly seen?

in immune reactions in vessels

What causes fibrinoid necrosis?

immune complexes of antigens and antibodies combined with fibrin (a protein)

Can the gross be seen in fibrinoid necrosis?

No, changes too small to see

What is the microscopic appearance of fibrinoid necrosis?

Vessel walls thickened, pinkish-red

What is the key association for fibrinoid necrosis?

Blood vessels and immune reactions

What is gangrene?

area of necrotic tissue invaded by bacteria

Where is gangrene commonly found?

internal organs like intestines or extremities w/poor blood supply

What is the gross of gangrene?

black and dead skin; underlying tissue

dry gangrene

Coagulative necrosis occurs due to loss of blood supply

wet gangrene

bacteria invades→ liquefactive or wet necrosis can develop

What are the two main types of gangrene?

Wet and dry

What are the characteristics of wet gangrene?

Common in the bowel, moist/swollen/dark tissue, bacteria, poor prognosis, venous obstruction

What are the characteristics of dry gangrene?

Common in a limb, dry/shrunken/black tissue, no bacteria, better prognosis,clear line of demarcation

What is gaseous gangrene?

a type of wet gangrene caused by anaerobic bacteria

Where can gaseous gangrene occur?

colon and muscle

Why is gaseous gangrene dangerous?

Gas build up within tissue can reduce blood supply and allow infection to spread

How is gaseous gangrene treated?

surgically removed to prevent spread of infection

Why are bacteria more likely to grow in gangrenous tissue?

Poor circulation

What nutrients allow bacteria to grow in dead tissue?

glucose

What type of necrosis occurs in a brain infarction?

Liquefactive necrosis

What type of necrosis occurs in a myocardial infarction?

Coagulative necrosis

What type of necrosis occurs in most infarctions?

Coagulative necrosis

What type of necrosis occurs in an infarction of the brain?

Liquefactive necrosis

What type of necrosis is associated with acute pancreatitis?

Fat necrosis

What type of necrosis is associated with tuberculosis?

Caseous necrosis

What type of necrosis is associated with immune reactions in blood vessels?

Fibrinoid necrosis

What condition involves poor blood supply and bacterial invasion of necrotic tissue?

Gangrene

What type of gangrene is moist, swollen, dark, and contains bacteria?

Wet gangrene

What type of gangrene is dry, shrunken, black, and has a line of demarcation?

Dry gangrene

the key association for liquefactive necrosis is the….

brain

What are the 9 ways cells are injured in the body.

Ischemia, Heat/Cold, radiation, mechanical damage, chemical toxins, microorganism, abnormal metabolites, nutritional deficits, imbalance of fluids or electrolytes