Patho Lecture Notes Cellular Adaptation CH5

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Patho Lecture 2-5-15

CH 5

Cells adapt to the (internal) environment. Cells will adapt

to a thicker layer to protect it from harm=law of adaptation. Adapt to increase

of demand.

Cellular adaptations:

In aging, cells tend to atrophy (get smaller). Decrease in

size

Hypertrophy

= increase cell size. Based on increased demand. get bigger. Lean muscles retain water

Metaplasia=

cells change from one from to another. Ex. Cuboidal to squamous cells. Occurs

in bronchials, with smoking. Can reverse if irritation is removed. Change in

form. Replacement of one type of cell with another type.

Dysplasia-

irregularity of cells. Indication of trouble. Size… etc is irregular/deranged.

Cells react to confusion of what is stimulating them.

Hyperplasia=

increase of the number of cells. Change is common with hormonal changes

(pregnancy) and is natural.

Anaplasia=

lack of change

Inside of cell there are things that accumulate that are

normal which are byproduct of the food, nutrients that we have broken down.

Some lipids, proteins, carbs, melanin are normal because natural from

nutrients. But some unnatural things can accumulate because of problems with

metabolism and chemical products are produced that are abnormal. Sometimes,

depending on what we take in; for instance we have vegetables at the grocery

stores that have been treated with pesticides or with radiation. So if

vegetable is not washed well, or if chemical gets into the plant from the soil

– who consumes them? Humans. They are digested and absorbed into the bloodstream.

Depending on the level of the chemicals, they can impact the cellular activity.

Inside the cell, nucleus, protein synthesis.. Is a protein being produced

abnormally.

Are the cells capable of repairing damage? Or is that

capacity diminished bc of that chemical? So that’s why we talk about

environment pollution (water drank, food ate, air breathe, or any exposure of)

that can be absorbed thru the blood stream , or radiation, that can go thru

body. When they accumulate in the body, theres increase in free radicals – damage the cells. Not only do they diminish cell’s

ability to protect itself and repair damage; it may induce disease changes.

Some can be ... {..casenogenic?}, in other words can affect cells they mutate

and do things they normally wouldn’t do. The longer it remains in the body

(i.e. Lead poisioning, asbestos..) the more pronounced the damage is. When a

damage cell divides it can only produce more damaged cells, causing more and

more percentage of cells in trouble. So that’s how cancer can begin. Water is

monitored and safe level. There are some things that stay in the body for a

long time and accumulate over the years. They are not easily excreted and can

become problems.

Pathological

calcifications- Abnormal tissue deposition of calcium salts. Should not be

in cell. Together with smaller amounts of iron, magnesium, and other minerals. Can

have areas that are calcified, hardened. If in wall of the blood vessel, like

an artery, that part of the artery will not be able to stretch the way that it

should. The artery loses elasticity, becomes hardened and damage is easier.

Dystrophic

calcification- Occurs in dying tissues.

Metastatic

calcification- are in normal tissues

What can cause

injury to the cell? It can be:

chemical (drugs, lead toxicity, mercury- avoid

seafood if high pollution/oil spill; carbon tetrachloride- chemical reageant

from drugs/antibiotics)

physical (mechanical, extreme temperature, or

electrical forces), radiation (ionizing – microwaving causes molecules in the

body to vibrate at a very rapid rate and mangle proteins/fibers and rearranges

the cell; UV – sun; ), lack of oxygen

biologic agents- virus, bacteria,

parasites because of toxins they release. And some grow through tissues, or

deprive host from blood supply

nutritional imbalances- excesses and

deficiencies. Obesity is strain on cardiac cells bc heart has to pump blood to

extra body mass accumulated. Exercise is more difficult, joints are strained bc

of weight to support (esp knees), shoe size has to be larger to accommodate the

extra weight. Anorexia nervosa intake is so much less than need. Deprive food

and inadequate food to supply metabolism.

Some are reversible. Counseling,

food planning, etc can help to change some of them.

Reversible cell injury impairs function, but cell doesn’t

die. Cell can recover from injury unless irreversible.

Cellular swelling- happens when Na/K

pump (pushes Na out of cell, and allows K in) inhibited from lack of oxygen or

cell poisioning, then sodium moves into the cell (bc pump is broken) leads to

water following sodium and cell swells. If it is reversed the pump will go into

action and get the sodium out, and goes back to normal. If not the cell will

burst = Hypoxic cell injury (due to

lack of oxygen in the cells/tissue)

Hypoxia=

inadequate oxygenation in the tissue.

Hypoxemia=

Inadequate/low oxygenation of the blood

Fatty changes- lose weight and replace

fat with lean muscle, things go back to normal. When fat is lost the cell does

better.

Free radicals

accumulation contributes to aging. Are highly chemically active and can cause

damage in the cell. Involved in lipid peroxidation, oxidative modification

(=damage) of proteins , and DNA damage. In the theory, free radicals contribute

to that…

Hypoxic cell

injury- can lead to acute

cellular swelling/edema because sodium moves in with the water. The longer

tissue is hypoxic, the more irreversible cell injury. So retention of fluid

(edema) in the extremities shouldn’t be taken lightly because it can indicate

underlying problem. Could be renal/heart failure, obstruction of lymphatic

vessels, malnutrition. Having a lot of fluid surrounding the tissue, means that

oxygenation of the tissues will decrease. A lot of fluid in the interstitial

space, oxygen leaving the blood to get to the tissues takes longer travel, and

tissues will end up with less oxygen they need- leading to hypoxic injury.

Regarding the air, if the overall oxygen concentration drops ( such as when

deep in a cave) then it will lead hypoxia. Respiratory disease such as

pneumonia from fluid accumulating, or COPD. Movement of oxygen to lungs is

limited, therefore concentration is low and tissue oxygen is low. Inability of

the cells to use oxygen like in poisoning, cells cannot extract oxygen. In

ischemia, decreased blood flow to tissue/organ.

What could happen if calcium can

not be used by the cell properly? Calcium is important in cell function as

second messenger. It can lead to disruption of how cell uses it… Or enzymes can

be activated in the wrong way.

Membrane can be damaged when the Na/K pump inactive,

Oxidization of phospholipid (happens when build up of reactive chemicals), and

ischemic activation of calcium.

Cell death – some

things can be reversed, others cannot. Cell death that is programmed= apoptosis. Meaning the cells

programmed to how many times they can divide. Is a natural phenomenon because

helps to eliminate worn out cells. Look at RBC’s life span around 20 days;

after that the membrane gets fragile, and they can be easily destroyed in the

spleen. This is to give way for the bone marrow to make new blood cells. It

helps to eliminate excess cells, and to replace those lost/damaged cells. Helps

to get rid of what has to go and new ones come. Also called cell suicide,

meaning it dies off gradually to make room for others. Other type is necrosis – area of the tissue that is

damaged/dead. For instance, if somebody has ulcer, the ulcer is

brown/green/unnatural= infected; and tissue is not lively. Tissue can not

increase no matter how much oxygen you pump into it. Must be cleaned so it can

grow. So necrosis refers to cell death in organ/tissues that is still alive.

(i.e. Diabetic pt that is not healing well). Interferes with cell

replacement/tissue regeneration, so it must be removed in order to heal.

Gangrene

is when a considerable amount of tissue is necrotized. Necrosis, gangrene or

infarction = Means tissue is already dead. Myocardial infarction (MI) means

that part of heart is damaged by blood flow blocked by a blood clot etc. Cannot

regenerate. But surrounding injured tissue may be revived. Ischemia= decreased

blood flow (not complete block of flow), means decreased oxygenation- but not

necrosis yet. Still reversible.

Dry

gangrene- means that the tissue is black, shrunk or shriveled, dry tissue.

Usually doesn’t spread across body, spreads slow. Tissues become dry and

shrinks. Skin is wrinkled, color changes to dark brown or black.

Wet

gangrene- area is moistened, inflamed, and smells bad (rotting eggs) bc of

bacterial infection. Type is called liquefarction because tissue melts into

watery Blelbs. Spread of infection is high.