Patho I , CELLULAR ALTERATIONS

Cells adapt to changes in the internal environment by changing in

size, number, and type

What is the decrease in cell size, usually as the result of a decrease in work demands or adverse environmental conditions?

atrophy

identify:

• decreasse in cell size, usuallt as the result of decrease in work demands or adverse environmental conditions

• reduces oxygen consumption and other cell functions

• entire tissue or muscle may atrophy

• Causes:

  • disuse

  • denervation

  • loss of endocrin stimulation

  • inadequeate nutrition

  • ischemia or decreased blood flow

atrophy

What is the being described here?

• increase in cell size and functioning tissue mass

• commonly seen in cardiac and skeletal muscle tissue

• may be due to biomechanical stress or neurohormonal factors

• limits are eventually reached —> increased size can no longer compensate for increased workload demands

hypertrophy

What is normal, physiologic hypertrophy?

increase in muscle mass with exercise/ increase in skeletal muscle mass with increased workload

what is pathologic hypertrophy?

result of disease/conditions. May be adapative or compensatory (for example if you remove on kidneym the kidney that is left has to increase work load)

What is the increase in the number of cells in an organ or tissue?

hyperplasia

Identify this:

• increase in the number of cells in an organ or tissue

• occurs in tissues that are capable of mitotic division

• often triggered by the same mechanisms as hypertrophy and can occur at the same time

• Physiologic ________ - Normal

  • hormonal

  • compensatory

• Non-physiologic(pathologic) _______:

  • may be a risk factor for some cancers

    • excessive hormonal stimulation

    • effects of growth factors on target issues

hyperplasia

What is the best definition for physiologic hyperplasia?

normal, important response in wound healing. may be hormonal or compensatory

• hormonal example: breat and uterine enlargements during pregnancy

• compensatory: regeneration of the liver after a partial hepatectomy

What is the best definition of non-physiologic (pathologic) hyperplasia

Mostly due to excessive hormonal stimulation or the effects of growth on target tissues.

• May be serious issue and risk factor for some cancers.

Examples: skin warts, beningn prostatic hyperplasia (BPH) (too many cells in prostate= enlarged prostate)

Identify this:

• Reversible change in which one adult cell type is replaced by another cell type

  • involves reprogramming of undifferentiated stem cells

  • usually in response to chronic irritation and inflammation- allows fragile cells to “substitute” with a tougher cell

  • primary tissue remains the same

  • ex: epithelial cells in the trachea and large airways of a smoker

metaplasia

Identify this:

• deranged cell growth that results in cells that vary in size, shape, and organization

  • minor _____ may be associated with irritation/inflammation

  • abnormal, but adaptive - may be reversed if the if the irritation is removed

  • ***Dysplastic changes are strongly implicated as a precursor of cancer

  • example: HPV, persistent infection can lead to ______

dysplasia

What changes are strongly implicated as a precursor of cancer?

dysplastic

What is the buildup of substances within a cell that cannot be immediately used or excreted? May be caused by:

• normal body substabnces (lipids, proteins, carbs, bilirubin, etc.)

• abnormal endogenous(comes from within the body( products (some genetic disorders)

• exogenous(comes form outside the body) products (lead poisoning)

intracellular accumulations

What is one example of intracellular accumulations from an exogenous product?

lead

Abnormal tissue deposition of calcium salts, iron, magnesium, and other minerals

various types

pathologic calcifications

The extend of cellular injury and death depends on:

• intensisty and duration of the injury

• type of cell involved

• blood supply to the cell

• nutritional status

• regenerative capactiy of the cell

What are some causes of cell injury

physical agents, radiation injury, chemical injury, biological agents, nutritional imbalances

What are some physical agents of cell injury?

• mechanical forces: trauma due to impact

  • tear tissue, fracture bones, injure blood vessels, and disrupt blood flow

• extreme of temperature: hot or cold

  • Intense heat: coagulation of blood vessels and tissue proteins

  • cold exposure: increases blood viscosity and induces vasoconstriction, leading to hypoxic cell injury

• electrical injury:

  • volatage

  • current type

  • amperage

  • pathway, this is a big deal with electrical injuries theres a pathway of destruction, most severe tissue injury sites are where the current enters and exit , the exit wounds are usually worse

  • resistance

  • interval

radiation injury:

• ionizing: free radiacal destroy cells

• ultraviolet radiation: causes sunburn and increases skin cancer risk

What kind of radiation injury is being described below:

1. directly breaks chemical bonds by the release of free radicals that destroy cells and directly hit target molecules in the cell

2. immediately kills, interrups cell replication, or causes genetic mutations

3. localized irridation is used in the treatment of cancer

4. rapidly dividing cells are more vulnerable to radiation injury than other tissues

5. long-term exposure can result in increased risk for various types of cancer

ionizing radiation

What kind of radiation injury is being described below:

1. causes sunburn and increases the risk of skin cancer

2. risk is determined by the type of UV rays, intensity of exposure, and amount of protective melanin pigment in the skin

3. skin damage occurs, as well as damage to the cellular DNA

ultraviolet radiation

What kind of cell injury being described here?

• Chemical agents can injure cell membranes or other cell structures and disrupt cellular processes

• medications/drugs: alcohol, prescription or over-the-counter drugs(ex: tylenol is toxic to liver), street drugs- capable of directly or indirectly damaging tissues

• mercury and lead: most toxic metals

chemical injury

What are some cell injuries from biologic agents?

• viruses

• bacteria

• fungi

• parasites

• ****Able to replicate and continute to produce their injurious effects

What is cell injury from nutritonal imbalances?

• nutritional excess and nutritional defciency

• obesity and starvation

What are the mechanisms of cell injury?

• Free radical injury

• Hypoxic cell injury*****

• imparied calcium homeostasis

identify what mechanish of cell injury this is:

• Free radiacals - highly reactive atoms with unpairs electron in the outer orbit

• free radicals react with molecules nearby: proteins, lipids, carbs

• free radicals damage cell membrnaes, inactive enzymes, and damage DNA
  
  

free radical injury

highly reactive atoms with an unpaired electron in the outer orbit

free radicals

identify what mechanism of cell injury this is:

• most common form of cellular injury

• hypoxia interrupts aerobic metabolism and the generation of ATP

  • cells need oxygen to generate ATP

• extent of injury depends on degree of oxygen deprivation, and the metabolic needs of the cell

hypoxic cell injury

What is hypoxia?

decreased oxygen

What is hypoxemia?

decreased oxygen in the blood

What is anoxia?

without oxygen

What is ischemia?

cell injury related to decreased oxygen supply from the blood

What is infarction?

cell death related to decreaed oxygen supply from the blood

What can hypoxia result from?

• indequate oxygen in the air

• respiratory disease

• ischemia

  • impaired oxygeb delivery and imparied removal of metabolic end products such as lactic acid

  • decrease in blood flow to certain tissures = decreased oxygen delivery. produces local tissue injury

• anemia

• edema

• inability of cells to use oxygen

What is the ultimate cause of cell death from many injuries?

hypoxia

What kind of metabolism is being described?

• when oxygen is given to a cell it produces ATP

• waste product: CO2

aerobic metabolism

What kind of metabolism is being descibed here?

• No oxygen

• uses energy stored to do what it needs to do

• waste product: lactic acid(makes cell swell)

anaerobic metabolism

How is “power failure” caused in the cell during hypoxic cell injury

1. aerobic —→ anaerobic metabolism

2. lactic acid accumulation leads leads to a reduction in cellular pH

3. low pH damages cellular structures and functions .(increased cell membrane permiability)

What happens when:

Reduced ATP —> failure of the Na/K - ATP pump

(during hypoxic cell injury)

1. intracellular potassium levels decrease

2. intracellular calcium, sodium and water levels increase —→ cellular swelling

Is hypoxic cell injury reversible?

yes, if oxygen is restored

Is complete cell death reversible?

no

Impaired calcium homeostasis

• normally, intracellular calcium levels are very low compared with extracellular calcium levels

• ischemia and/or certain toxins can increase intracellurlar calcium levels

• increased intracellular calcium levels activate enzymes with damaging effects

What description best fits reversible cell injury?

• may impair cellular function but does not result in cell death

• two patterns:

  • cellular swelling- impairment of the Na/L - ATP membrane pump. usually the result of hypoxic cell injury

  • Fatty change- worse prognosis but still reversible. Indicates severe injury. either cells are presented with a increased fat load, or injured cells are unable to metabolize fat properly. Fatty infiltrates occur within and around the cell.

What are the pattern of reversible cell injury?

• cellular swelling- impairment of the Na/L - ATP membrane pump. usually the result of hypoxic cell injury

• Fatty change- worse prognosis but still reversible. Indicates severe injury. either cells are presented with a increased fat load, or injured cells are unable to metabolize fat properly. Fatty infiltrates occur within and around the cell.

What is cellular swelling?

Reversible patter of cell injury from impairment of the Na/L - ATP membrane pump. usually the result of hypoxic cell injury

What is fatty change?

Reversible cell injury ppatter with worse prognosis but still reversible. Indicates severe injury. either cells are presented with a increased fat load, or injured cells are unable to metabolize fat properly. Fatty infiltrates occur within and around the cell.

What description best fits programmed cell death/ apoptosis?

• selctive process that eliminates injured and aged cells

• controls tissue regulation

• examples:

  1. Programmed destruction of cells during embryonic development

  2. Hormone-dependent reduction of tissue

  3. death of immune cells

  4. cell death by cytotoxic cells

  5. cell death of proliferating cell populations

What is apoptosis?

programmed cell death; a selective process that eliminates injured and aged cells and controls tissue regulation

What description best fits cell death- necrosis

• cell death in an organ/ tissue that is still part of a living organism

• impairs cell membrane integrity, causes enzymatic breakdown of cell parts, and triggers inflammatory response. Often interfers with cell replacement and tissue regeneration

• many types

  • gangrene

What is gangrene?

• considerable mass of tissue has undergon necrosis

• classified as

  • dry

  • moist/wet

  • gas

What results from interference with arteriole blood supply with normal venous return; tissue becomes dry and shrinks

• color: dark brown/black tissue

• slow spread

• has clear line of demarcation (clear line between living and dead tissue)

• usually confined to extremities

• symptoms are less severe than moist gangrene

dry gangrene

What is king of gangrene is being descibed here:

• Bacterial invasion plays a major role; associated with venous blood return impairment; skin is moist, cold, swollen; spread of tissue damage is rapid

• normal arteriole blood flow

• issue with venous blood flow

• colors, yellow, brown, red, has a waxy/shiny apperance

• foul smell/odor (bacteria makes it smell)

• no clear line of demarcation

• severe systemic (in whole body)symptoms

moist gangrene

What kind of gangrene is being described:

Special type of moist gangrene from Clostridium perfringens(bacteria) infection; hydrogen sulfide gas bubbles form on muscle; serious and potentially fatal

• amputation likely required to prevent spread

gas gangrene