Altered cells and tissue function

cell membrane function

cell membrane function

interact with outside world, transport

chromosomes and their genes function in cells

code information and translate instructions

mitochondria function

create energy

endoplasmic reticulum and Golgi bodies function

make protein machinery to do things

dysplasia

refers to changes in cell size, shape, uniformity, arrangement and structure

large nuclei are frequently present and the rate of mitosis in increased- meaning they are replicating faster than they should

atrophy

decrease in cellular size ex; dementia, muscle loss

hypertrophy

increase in cellular size

hyperplasia

increase in number of cells

metaplasia

replacement of one type of cell with another

cardiomyopathy

hypertrophy of heart tissue

breast tissue adaptation in puberty, pregnancy, and menopause

puberty - hyperplasia

pregnancy - hypertrophy

menopause - atrophy

cellular changes in dysplasia

• large squamous cells with small nuclei

• nucleus increasing in size and darkening in color

• markedly enlarged and darkened nucleus with abnormal chromatin

anaplasia

describes cells that have lost the distinct characteristics which define them as particular tissue types

oxidative stress

exposure of cells to reactive oxygen species (ROS), toxic oxygen molecules (radicals) that are formed by the reaction between oxygen and water during mitochondrial respiration

• can be increased in many conditions including aging, infection, use of drugs

• ROS species include: superoxide, hydrogen peroxide

free radical injury

damage of DNA or RNA

oxidations of polyunsaturated fatty acids in lipids

oxidations of amino acids in proteins

damage to mitochondria

• damages cells ability to function and replicate properly

• results in inflammation

• long term effects are heart disease, diabetes, cancer

hypoxic injury

single most common cause of cellular injury

results from decreased oxygen in air, loss of hemoglobin r decreased efficacy of hemoglobin, decreased RBC production etc.

ischemia

most common cause of hypoxia

ischemia - reperfusion injury

reoxygenation can cause damage

• when you reflood the body with oxygen it can cause an excess of oxygen and create reactive oxygen species, cause increased intracellular calcium, inflammation, complement activation resulting in inflammation and damage

examples of immunologic and inflammatory injury

chrons, diabetes, rheumatoid arthritis

cellular accumulations

a manifestation of cellular injury caused by an infiltration of excess cellular products such as water, lipids, proteins

bruising

1. extravasated red cells (broken red cells accumulate in skin)

2. phagocytosis of red cells by macrophages causes colour change

3. hemosiderin and iron free pigments

necrosis

irreversible cell injury causing death - causes by hypoxic injury

coagulative hypoxic injury

in kidneys and heart-albumin becomes firm and tissue swells

liquefactive hypoxic injury

in glial cells and brain - enzymes in brain cells liquify cells and form cysts

apoptosis

cellular death caused by other cell processes besides hypoxia such as mitochondrial death

caseous hypoxic injury

from TB in lungs

fat hypoxic injury

lipases break down breast and pancreas tissue, combines with calcium and necrosis looks chalky and white

gangrenous hypoxic injury

severe blockage in lower leg arteries, skin breaks down, bacteria move in and tissue dies

gas gangrene hypoxic injury

caused by infection of tissue with clostridium species - anaerobic bacteria make enzymes that destroy tissue

pathophysiology of cardiac hypertrophy

can occur in right or left ventricle

increased pressure in pulmonary or systemic circulating

cardiac muscle becomes thickened and stiff as a result of increased myocardial cell size

lack of compliance results in lack of adequate filling and decreased cardiac output, heart would not be able to supply for larger oxygen demand in body

eventually results in heart failure

clinical manifestation in cardiac hypertrophy

dyspnea- trouble breathing

angina- heart pain

syncope - fainting

cardiac dysrhythmias - because heart is not perfused well

fatigue - from lack of oxygen

treatment of cardiac hypertrophy

surgical (septal myectomy)

drugs:

• drugs that relax the ventricles (calcium channel blockers such as diltiazem)

• drugs that reduce the workload of the heart (beta blockers such as metoprolol)

• drugs decrease the pressure that the heart must pump against ( beta blockers such as propranolol)

  nonpharmacologic - low level exercise, healthy weight, nutrition, reduce alcohol

acromegaly -cellular hyperplasia

hyperplasia resulting from excessive growth hormone stimulation

usually caused by a pituitary tumor ( adenoma )

GH binds to cell receptors and stimulates cell proliferation GH stimulates the IGF - 1 in the liver which promotes growth in bones, cartilage, soft tissues and organs

aging and altered cellular and tissue biology

systemic aging causes sarcopenia (loss of muscle) from atrophy and loss of cells

the cellular changes proceed slowly and in small increments

maintaining muscle strength and mobility is key to a long and healthy life

somatic death

death of entire person

their are many postmortem changes

algor mortis (decreased body temp), livor mortis (purple color from blood pooling), rigor mortis (acidic compounds build up in muscles causing stiffening), an postmortem autolysis (release of enzymes and petrification)