Transport in Humans Flashcards

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1
Q

Description of plasma

A
  • Liquid part of blood
  • Mainly water
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2
Q

Function of plasma

A
  • Carries blood cells around the body
  • Carries dissolved nutrients, hormones, carbon dioxide and urea
  • Distributes heat around the body
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3
Q

Description of erythrocytes

A

Biconcave, disc-like cell with no nucleus; Millions in each mm cubed of blood

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4
Q

Function of erythrocytes

A

Transport oxygen - contain mainly haemoglobin

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5
Q

Description of lymphocytes

A

About the same size as red cells with a large spherical nucleus

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6
Q

Function of lymphocytes

A
  • Produced antibodies to destroy microorganisms
  • Some persist in our blood after infection and give us immmunity
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7
Q

Description of phagocytes

A

Much larger than red cells with a spherical or lobed nucleus

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8
Q

Function of phagocytes

A

Digest and destroy microorganisms that have infected our bodies

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9
Q

Description of platelets

A

The smallest cells -really fragments of other cells

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10
Q

Function of platelets

A

Release chemicals to make blood clot when we cut ourselves

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11
Q

Describe an immune response

A
  1. A pathogen enters the body
  2. Antigens on the microbe’s surface alert the white blood cells
  3. Lymphocytes release Y-shaped antibodies against the microbe
  4. Antibodies stick to the antigens and either stick microbes together so that phagocytes can ingest them more easily; mark microbes for attack by phagocytes; cause microbes to burst open or neutralise poisons (toxins) produced by the pathogen
  5. Phagocytes surround and engulf the microbe
  6. Phagocytes use digestive enzymes to destroy the microbes
  7. Memory cells remain in the blood after the attack, ready to produce a fast response if the same microbe infects the body again
  8. Once memory cells have been made, we are said to be immune to this disease
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12
Q

How does a vaccine work?

A

It injects an inactive pathogen to activate an immune response and produce memory cells

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13
Q

How does exposure to air stimulate platelets to clot the blood?

A

Platelets produce a chemical which causes the soluble plasma protein fibrinogen to change into insoluble fibres of fibrin. The fibrin forms a network across a wound, in which red blood cells get trapped forming a clot and preventing further blood loss and the entry of microorganisms

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14
Q

Describe a heart beat

A
  1. Blood enters the atria though cannot pass into the ventricles because the atrio-ventricular valves are closed
  2. The walls of the atria constrict, easing the blood pressure which forces the atrio-ventricular valves open and blood passes into the ventricles
  3. When the ventricles are full, they contract, increasing the blood pressure and closing the atrio-ventricular valves, preventing blood from returning to the atria
  4. The ventricles continue to contract and the blood pressure increases, forcing open the semi-lunar valves and ejecting blood into the pulmonary artery and the aorta
  5. As the ventricles empty, higher pressure in the arteries closes the semi-lunar valves and the cycle begins again
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15
Q

What does adrenaline do?

A

Increase heart rate

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16
Q

What happens when we exercise?

A

Our muscles need more energy so respire more and require more oxygen. To deliver the extra oxygen heart rate increases and stroke volume increases

17
Q

How does our heart rate increase during exercise?

A

Our muscles produce more carbon dioxide through aerobic respiration. Receptors in the aorta and carotid artery (to the head) detect this change and send nerve impulses to the medulla through the sensory nerve. The medulla responds by sending an impulse along the accelerator nerve

18
Q

What happens we when stop exercising?

A

Carbon dioxide levels return to normal and the medulla receives fewer impulses so sends a signal along the decelerated nerve to return the heart rate to normal

19
Q

Factors that increase the risk of coronary heart disease

A
  • Hereditary - some people inherit a tendency to develop coronary heart disease
  • High blood pressure - puts more strain on the heart
  • Diet - eating larger amount of saturated fats is likely to raise cholesterol levels
  • Smoking - raises blood pressure and makes blood clots more likely to form
  • Stress - raises blood pressure
  • Lack of exercise - regular exercise helps to reduce blood pressure and strengthens the heart
20
Q

Features of arteries

A
  • Small lumen
  • Thick wall with elastic fibres
  • Carries blood away from the heart
  • High pressure
  • Muscle constricts/dilated, elastic fibre stretches/recoils
  • No valves
21
Q

Features of veins

A
  • Large lumen
  • Lining (endothelium)
  • Carries blood towards the heart
  • Low pressure
  • Thinner wall than arteries
  • Less muscle and elastic tissue than arteries
  • Yes valves
22
Q

Features of capillaries

A
  • Room for only one blood cell
  • Wall is one cell thick
  • Exchanges of molecules
  • Very low pressure
  • No muscle or elastic fibre
  • No valves
23
Q

What is the name of the vessel that carries blood to the lungs?

A

Pulmonary artery

24
Q

What is the name of the vessel that carries blood to the body?

A

Aorta

25
Q

What is the name of the vessel that carries blood to the liver?

A

Hepatic artery

26
Q

What is the name of the vessel that carries blood to the kidneys?

A

Renal artery

27
Q

What is the name of the vessel that carries blood from the digestive system to the liver?

A

Hepatic portal vein

28
Q

What is the name of the vessel that brings blood from the head?

A

Superior Vena Cava

29
Q

What is the name of the vessel that brings blood from the body?

A

Inferior Vena Cava

30
Q

What is the name of the vessel that brings blood from the liver?

A

Hepatic vein

31
Q

What is the name of the vessel that brings blood from the kidneys?

A

Renal vein