Human Biology

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  • Created by: kez
  • Created on: 03-11-12 04:01
What is oxygenated blood?
Blood with a high proportion of oxyhaemoglobin. Oxyhaemoglobin is bright red in colour, so the blood in the arterties (excluding the lungs) is bright red. Haemoglobin is dark red or purplish in colour.
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What is deoxygenated blood?
Blood that has released its oxygen. It is dark red in color with a tinge of blue. Found in veins and pulmonary artery. Oxygen bonds to haemoglobin in the blood cells & transported where it is needed in the body & exchanges with carbon dioxide.
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Why are red blood cells well suited to their function of oxygen transport?
Because they contain haemoglobin (able to combine with oxygen), have no nucleus (more room for haemoglobin), are shaped like biconcave discs (more room for haemoglobin).
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How is the carbon dioxide in the blood carried?
7-8% is dissolved in the plasma and carried in solution. 22% combines with the globin part of the haemoglobin to form carbaminohaemoglobin. 70% is carried in the plasma as bicarbonate ions, HCO3-.
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What occurs in the alveoli (air sacs of the lungs)?
They are surrounded by a dense network of capillaries. Carbon dioxide dissolved in the plasma diffuses out of the blood into the air in the alveolus. Carbaminohaemoglobin breaks down, carbon dioxide molecules released also diffuse into the alveolus.
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What happens to the hydrogen and bicarbonate ions in the alveoli?
They recombine to form carbonic acid, which then breaks down under enxyme action into water and carbon dioxide. This carbon dioxide also diffuses into the alveolus.
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What are nutrients?
Essential elements and molecules obtained from food. Inorganic nutrients transported as ions. Important ions dissolved in blood plasma are sodium, calcium, potassium. Organic nutrients dissolved - glucose, vitamins, amino acids, fatty acids, glycerol
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What are wastes (metabolic wastes)?
Substances produced by the cells that cannot be used, would be harmful if allowed to accumulate. Mos timportant organic wastes transported in solution in blood plasma - urea, creatinine and uric acid.
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What is the heart?
A pump that pushes blood around the body. Located - middle of the chest cavity. Conical. Around the heart, membrane called pericardium. Holds heart in place but allows it to move. Wall of heart made of cardiac muscle.
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What are blood vessels?
Blood is pumped by heart into blood vessels, carry blood to the cells of body or lungs and then bring back to heart again. Same blood flows continuously through the heart, referred to as circulation.
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What are the functions of arteries, capillaries, and veins?
Arteries carry blood away from the heart, capillaries are tiny vessels that carry blood between the cells (form a network, carrying blood to nearly every cell in body), and veins carry blood back to the heart.
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What is the cardiac cycle (heartbeat)?
A sequence of events that occurs in one complete beat of heart. Pumping phase of cycle (heart contracts) - systole. Filling phase (muscles relax) - diastole. Contraction of the atria - atrial systole. Ventricles contract - ventricular systole.
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Explain cardiac output.
The amount of blood leaving one of the ventricles every minute. CARDIAC OUTPUT (mL) = STROKE VOLUME (mL) x HEART RATE (beats/minute).
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What is vasocontriction and vasodilation?
Vasoconstriction is the contraction of a blood vessel. The relax of the muscle causing increased blood flow to an organ is vasodilation.
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What are arterioles?
The large arteries that receive blood pumped by the ventricles divide into smaller arteries. These in turn divide into very small arteries, known as arterioles. These supply blood to the capillaries. Have smooth muscle in their walls.
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What are veins and venules?
Veins carry blood towards the heart, don't have muscular wars, are not able to change their diameter in the way arteries do. Venules are tiny veins that carry blood away from the capillaries, also cannot change diameter b/c no muscle in their walls.
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What is the SA node?
A collection of nerve cells. The SA node acts as a 'pacemaker' for the heart. It is found in the wall of the right atrium of the heart. Begins each cardiac cycle with nerve impulses that spread over the atria causing them to contract.
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Other cards in this set

Card 2

Front

What is deoxygenated blood?

Back

Blood that has released its oxygen. It is dark red in color with a tinge of blue. Found in veins and pulmonary artery. Oxygen bonds to haemoglobin in the blood cells & transported where it is needed in the body & exchanges with carbon dioxide.

Card 3

Front

Why are red blood cells well suited to their function of oxygen transport?

Back

Preview of the front of card 3

Card 4

Front

How is the carbon dioxide in the blood carried?

Back

Preview of the front of card 4

Card 5

Front

What occurs in the alveoli (air sacs of the lungs)?

Back

Preview of the front of card 5
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