Pathology PresentationImportant Terms and Definitions

Dr. Asra Hameed Pharm.D (JUW) asra_hameed1@hotmail.com

1. Ischemia• Ischemia usually happens because of a shortage

of blood and oxygen to the heart muscle. • It is usually due to narrowing or blockage of one

or more of the coronary arteries (which supply blood to the heart muscle).

• In many cases ischemia is a temporary problem.

2.Hypoxia• A deficiency of oxygen reaching the tissues of the

body • There are four types:

hypoxemic, from low blood oxygen content anemic, from low blood oxygen-carrying

capacity distributive, from low blood flow histotoxic, from poisoning

• If not reversed quickly, hypoxia can lead to necrosis (tissue death), as in heart attack.

Ischemia and HypoxiaIschemia

• Ischemia is insufficient blood flow to provide adequate oxygenation.

• Ischemia always results in hypoxia;

Hypoxia• This, in turn, leads to

tissue hypoxia (reduced oxygen) or anoxia (absence of oxygen).

• hypoxia can occur without ischemia if, for example, the oxygen content of the arterial blood decreases as occurs with anemia.

3.Necrosis • Necrosis is the premature death of cells and living

tissue.• Necrosis is caused by factors external to the cell

or tissue, such as infection, toxins, or trauma.

4.Infarction• Obsolete term for fracture; especially one without

displacement.• The term "myocardial infarction" focuses on the

myocardium (the heart muscle) and the changes that occur in it due to the sudden deprivation of circulating blood.

• The main change is necrosis (death) of myocardial tissue.

Necrosis and Infarction(localized tissue death)

• Infarction refers to tissue death(necrosis) that is caused by a local lack of oxygen to an organ. • The most common type of infarction people are familiar with

is a myocardial infarction or heart attack. • Basically one or more of the coronary arteries that supply

the heart with blood gets occluded from atherosclerosis (hardening and thickening of the arteries).

• Because the blood can no longer reach that particular portion of the heart, that portion of the heart muscle dies.

• When portions of the heart muscle die it can cause an arrhythmia (irregular heart beat) and the patient has a “heart attack”.

5.Atrophy• Atrophy, decrease in size of a body part, cell,

organ, or tissue. • In atrophy of an organ or body part, there may be

a reduction in the number or in the size of the component cells, or in both.

• One example of atrophy is the progressive loss of bone that occurs in osteoporosis

6.Hypertrophy • Abnormal enlargement of a part or organ;

excessive growth. OR • Excessive growth or accumulation of any kind. • Cardiac hypertrophy is a thickening of the heart

muscle (myocardium) which results in a decrease in size of the chamber of the heart, including the left and right ventricles.

• A common cause of cardiac hypertrophy is high blood pressure (hypertension) and heart valve stenosis.

Atrophy and HypertrophyHypertrophy

• In hypertrophy, the rate of synthesis is much higher than the rate of degradation of muscle contractile proteins, leading to an increase in the size or volume of an organ due to enlargement of existing cells.

• This defect may occur as a result of lack of nutrition, loss of nerve supply, micro-gravity, ageing, systemic disease, prolonged immobilization or disuse.

Atrophy• When a muscle remains in

disuse for a long period, the rate of degradation of contractile proteins becomes greater than the rate of replacement, resulting in muscle atrophy.

• This defect may occur as a result of lack of nutrition, loss of nerve supply, micro-gravity, ageing, systemic disease, prolonged immobilization or disuse.

7.Hyperplasia• This disease is associated with the increase in

number of cells. • As a result of this disease, an organ can get

enlarged. • The cells look like normal cells but they are more

in number if we compare them with normal human body.

8.Metaplasia• Transformation of one tissue into another • Abnormal replacement of cells of one type by

cells of another

Hyperplasia and MetaplasiaHyperplasia

• Hyperplasia is increased cell numbers in response to hormones and other growth factors; occurs in tissues whose cells are able to divide or contain abundant tissue stem cells, whereas

Metaplasia• Metaplasia is change in

phenotype of differentiated cells, often in response to chronic irritation, that makes cells better able to withstand the stress; usually induced by altered differentiation pathway of tissue stem cells; may result in reduced functions or increased propensity for malignant transformation.

9.Aplasia• Aplasia is defined as incomplete or faulty

development of an organ or body part.• Thumb hypoplasia, also commonly called

hypoplastic thumb, means that your child’s thumb is unusually small or underdeveloped. Thumb aplasia means that your child’s thumb is missing altogether.

10.Anaplasia• It is the change in the structure of cells and their

orientation to each other.• (ana- means excessive, -plasia means formation)• This abnormal cell development is characteristic

of tumor formation in cancers.

Aplasia and AnaplasiaAplasia

• Aplasia is when an entire organ or a part of an organ is missing, means incomplete tissue formation

Anaplasia• Anaplasia is abnormal

tissue formation.• When differentiation of

cells gets back to the original cells this situation is called as Anaplasia.

Any Question?????The End