Blood + blood cells Flashcards

1
Q

What is the composition of blood?

A

Plasma, Erythrocytes, Leucocytes and Thrombocytes.

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2
Q

What is the composition of plasma?

A

Plasma is straw - coloured liquid and it is mostly water with dissolved nutrients, hormones, salts and proteins.

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3
Q

What is the function of plasma?

A

Plasma transports: carbon dioxide to the lungs for gaseous exchange; glucose from the small intestine to the cells for energy production, nutrients from the small intestine to the cells for growth and repair and other waste products away from the cells to be removed from the body by urea or heat.

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4
Q

What is the composition of erythrocytes?

A

Erythrocytes are red blood cells that make up 45% of blood volume. These cells are formed into a biconcave disc shape to extend the surface area and have to contain enough haemoglobin.

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5
Q

What is the function of Erythrocytes?

A

The erythrocytes function is to carry oxygen to specific parts of the body and carbon dioxide to the lungs. This is why a high level of haemoglobin is required as haemoglobin is the carrier of oxygen + CO2.

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6
Q

What is the function of Leucocytes?

A

Leucocytes are active in the immune system as they are responsible for fighting infections by identifying, engulfing and destroying foreign organisms.

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7
Q

What is the function of Thrombocytes?

A

Thrombocytes are cell fragments that move through the blood stream to be used to fix any wounds or to be disposed off.

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8
Q

What is the function of arteries?

A

Arteries are the blood vessels that deliever oxygenated blood from the heart to the body at a high pressure.

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9
Q

What is the structure of arteries?

A

Arteries have three muscular layers:
The intima which is lined by a smooth tissue called endothelium.
The media which is the middle layer which allows the arteries to allow the high pressure.
And the adventitia which is connective tissues that connect the arteries to other tissues.

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10
Q

What is the structure of arterioles?

A

Arterioles are arteries’ smaller branches that connect to the capillaries.

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11
Q

What is the function of arterioles?

A

Arterioles regulate blood flow and pressure as they constrict and regulate under the control of the sympathetic nervous system.

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12
Q

What is the structure of the veins?

A

Veins are less muscular than arteries and are closer to the skin and veins have valves to prevent the back flow of blood.

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13
Q

What is the function of veins?

A

Veins carry blood to the heart.

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14
Q

What is the function of capillaries?

A

Capillaries are the smallest blood vessel - one cell thick. Capillaries exchange materials and cells such as oxygen and nutrients from the blood stream to bodily tissues and collect CO2 and waste material fluid to return them to veins.

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15
Q

What is the function of venuoles?

A

Venuoles are capillaries put together to form a blood vessel to transport deoxygenated blood from the capillary beds to the veins. Venuoles have three layers: an inner endothelium, a middle layer of muscle and elastic tissue that is poorly developed to make the walls thinner than arterioles and an outer layer of fibrous connective tissues.

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16
Q

What is venous return (VR)?

A

Venous return is the flow of blood back to the heart.

17
Q

Does stroke volume depends on venous return?

A

If venous return is low then stroke volume is low which reduces overall cardiac output.

18
Q

How do veins prevent back flow?

A

Veins have valves as active mechanisms to prevent the back flow. The body also has skeletal and respiratory pumps to prevent backflow.

19
Q

What is the function of the skeletal pump?

A

When moving, our muscles contract forcing all the blood to move towards the heart.

20
Q

What is the function of the respiratory pump?

A

When breathing air in and out of the lungs, the volume of the thoracic cavity changes, which causes pressure to force the blood in abdominal veins back into the heart.

21
Q

What is vasomotor control?

A

Vasomotor control is the flow and pressure of blood controlled by the vasomotor centre in medulla in the brain. It is stimulated by baroreceptors in the aorta and corotid arteries.

22
Q

What is vasomotor tone?

A

Vasomotor tone is the blood vessels receiving impulses. The VC controls this stimulus by a high vasomotor tone leads to vasoconstriction, lumen decreases, blood pressure decreases and blood flow decreases.
Low vasomotor tone leads to vice versa.

23
Q

Describe vascular shunt.

A

During exercise, the demand for O2 for the skeletal muscles increases massively and more oxygenated blood is needed to meet this demand. The increased stroke volume and heart rate leads to an increased CO2 + O2 so the blood needs to be redistributed so more blood reaches the skeletal muscles instead of other organs. This redistribution is achieved by vasodilation of arterioles to the skeletal muscles and the vasoconstriction of the arterioles for other organs.