A-Level Biology Revision Notes

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1. Define terms:

Rouleaux:

A cylindrical structure in the blood formed from several red blood cells piled one upon the other and adhering by their rims.

Transient Ischaemic Attack: (TIA)

The result of temporary disruption of the circulation to part of the brain due to embolism, thrombosis to brain arteries, or spasm of the vessel walls. The symptoms maybe similar to those of a stroke but patients recover within 24 hours.

ESR: (Erythrocyte Sedimentation Rate)

The rate at which red blood cells (erythrocytes) settle out of suspension in blood plasma, measured under standardized conditions. The ESR increases if the level of certain proteins in the plasma rises, as in rheumatic disease, chronic infections, and malignant disease, and thus provides a simple but valuable screening test for these conditions.

Serum Ferritin:

An iron-protein complex that is one of the forms in which iron is stored in the tissues.

Reticulocytes:

An immature red blood cell (erythrocyte). Reticulocytes maybe detected and counted by staining living red cells with certain dyes that result in the formation of a blue precipitate (reticulum) within the reticulocytes. They normally comprise about 1% of the total red cells and are increased (reticulocytosis) whenever the rate of red cell production increases.

Total Iron Binding Capacity:

A test that measures indirectly the transferrin level in the bloodstream. Transferrin is a  that carries iron in the body. Normal values are 240 to 450 . This test is used to evaluate . Greater than normal TIBC can be seen in: iron deficiency anemia, late pregnancy, and . Lower than normal TIBC can be seen in , , hypoproteinemia, , and . The use of birth control pills can lead to increased TIBC measurements.

Splinter Haemorrhages:

A linear haemorrhage below the nails, usually the result of trauma but also occurring in such conditions as subacute bacterial endocarditis or severe rheumatoid artheritis.

Microcytosis: (Hypochromic microcytic)

The presence of abnormally small red blood cells (microcytes) in the blood. Microcytosis is a feature of certain anaemias (microcytic anaemias), including iron-deficiency anaemias, certain haemoglobinopathies, anaemias associated with chronic infections etc.

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Characteristic features: Low MCV. (under 80 fl).

2. Mechanisms of TIA:

  • Symptoms:

Sudden loss of function in one region of the brain. Symptoms reach peak in seconds, lasts for minutes or hours. But stops in under 24 hours.

Site of lesion is suggested by the pattern of attack.

  • Signs:

Diagnosis of TIA is often based on description of event. During attack loss of function can be demonstrated. Consciousness is usually preserved.

Clinical evidence of embolus:

-Carotid artery stenosis (arterial bruit)

-Atrial fibrillation (or other disrhythmia)

-Valvular Heart disease or endocarditis

-Recent Myocardial Infarction

-Difference between right ...

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This is well researched report that contains a lot of information. 1. The report lacks direction. There should be an aim and an introduction that lays out the intention of the report. 2. The researched information needs to be referenced. 3. Information that has been taken from a source should be rewritten. 4. There are too many lists. Descriptions and explanations are better. ***