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Human Biology > The Circulatroy System > Flashcards

The Circulatroy System Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

What is the name for the central space or cavity in a blood vessel?

A

The lumen

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2
Q

What is the lumen lined with in blood vessels?

A

A single layer of cells called the endothelium.

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3
Q

What are arteries and what is their structure?

A

Arteries carry blood away from the heart. Arteries have an outer layer of connective tissue containing elastic fibres and a thick middle layer containing smooth muscle with more elastic fibres. They have medium sized lumen.

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4
Q

What is vasoconstriction?

A

Vasoconstriction is the contraction of the smooth muscle of the arteries.

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5
Q

What is vasodilation?

A

Vasodilation is the relaxation of the smooth muscles in the arteries.

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6
Q

During exercise what happens to the arteries supping the muscles?

A

They vasodilate to increase blood flow.

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7
Q

During exercise what happens to the arteries supplying the abdominal muscles?

A

They vasoconstrict which reduces blood flow.

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8
Q

What are veins and what is their structure?

A

Veins carry blood towards the heart. Veins have an outer layer of connective tissue containing elastic fibres but a much thinner muscular wall than arteries. The central lumen of a vein is relatively wider than that of an artery. Valves are needed to prevent the back flow of blood as the blood flowing back to the heart at a low pressure and generally against gravity.

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9
Q

What is the structure of capillaries?

A

Capillary walls are only one cell thick, which allows quick and efficient exchange of substances with tissue.

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10
Q

What is pressure filtration?

A

Pressure filtration causes plasma to pass through capillary walls into the tissue fluid surrounding the cells.

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11
Q

What is the difference between plasma and tissue fluid.

A

Plasma contains plasma proteins that are to big to fit through the capillary walls.

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12
Q

What does tissue fluid contain?

A

Glucose, oxygen and dissolved substances, which supply the tissues with all their requirements.

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13
Q

What are lymph vessels?

A

Lymph vessels absorb excess tissue fluid and return it as lymph fluid to the circulatory system via the lymphatic system.

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14
Q

What are the four chambers of the heart?

A

Right atrium, right ventricle, left atrium and left ventricle.

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15
Q

What side of the heart collects deoxygenated blood from the body and pumps it to the lungs?

A

The right hand side.

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16
Q

What is the cardiac output and how is it calculated?

A

The cardiac output is the volume of blood pumped through each ventricle per minute. CO=HR x SV

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17
Q

What is the cardiac cycle?

A

The cardiac cycle is the pattern of contraction (systole) and relaxation (diastole) of the heart muscle in one complete heartbeat.

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18
Q

Explain the process of the cardiac cycle.

A
  • Atria and ventricles are relaxed
  • Blood flows into the right atrium from the vena cava and into the left atrium from the pulmonary vein
  • Volume of blood increases and increased pressure opens AV valves
  • Blood flows down into the ventricles
  • SL valves are closed
  • The atria contract, forcing the remaining blood through the AV valves into the ventricles
  • Ventricles contract, closing AV valves
  • SL valves are pushed open and blood is pumped out from the right ventricle to the pulmonary vein and from the left ventricle to the aorta.
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19
Q

What sets the rate at which the heart contracts? And where is it located?

A

The auto-rhythmic cells of the sino-atrial node (SAN) or pacemaker located in the wall of the right atrium.

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20
Q

Explain the role of impulses in the cardiac cycle.

A

The timing of cardiac muscle cell contraction is controlled by impulses from the SAN spreading through the atria causing atrial systole. The impulses then travel to the atrioventricular node (AVN) located in the centre of the heart. Impulses from the AVN travel down fibres in the central wall of the heart and then up through the walls of the ventricles, causing ventricular systole.

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21
Q

What can an electrocardiogram detect?

A

The currents created by the impulses in the heart.

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22
Q

What part of the brain regulates the rate of the SAN?

A

The medulla through the ANS.

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23
Q

What does a sympathetic (accelerator) nerve release to increase the heart rate?

A

Noradrenaline

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24
Q

What does a parasympathetic nerve release to decrease the heart rate?

A

Acetylcholine

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25
Q

What happens to the blood pressure during ventricular systole and diastole?

A

It increases during systole and decreases during diastole.

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26
Q

How is blood pressure measured?

A

Using a sphygmomanometer

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27
Q

What is a typical blood pressure of an young adult?

A

120/80 mmHg

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28
Q

What is hypertension ?

A

High blood pressure and is a major risk for many diseases and conditions including coronary heart disease.

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29
Q

What is atherosclerosis?

A

Atherosclerosis is the accumulation of fatty material (consisting mainly of cholesterol), fibrous material and calcium, forming an atheroma or plaque beneath the endothelium of the artery wall.

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30
Q

What happens to the artery as an atheroma grows?

A

The artery thickens and loses its elasticity as well as a reduced diameter of the lumen which restricts blood flow and results in increased blood pressure.

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31
Q

What happens when an atheroma is ruptured?

A

The endothelium is damaged, which releases clotting factors that activate a cascade of reactions, resulting in the conversion of the inactive enzyme prothrombin to active thrombin.

32
Q

What does thrombin cause?

A

Thrombin causes molecules of the plasma protein fibrinogen to form threads if fibrin which form a mesh work that clots the blood, seals he wound and provides a scaffold for the formation of scar tissue.

33
Q

What is the formation of a clot referred to as?

A

Thrombosis

34
Q

What happens when a thrombus breaks free?

A

An embolus is formed which travels through the bloodstream until it blocks a blood vessel.

35
Q

What might a thrombosis in a coronary artery lead to?

A

A myocardial infraction (also known as a heart heart).

36
Q

What might a thrombosis in an artery in the brain lead to?

A

A stroke

37
Q

What is peripheral vascular disease?

A

The narrowing of arteries due to atherosclerosis of arteries other than that of those of the heart or brain.

38
Q

What is a deep vein thrombosis (DVT)?

A

A blood clot that forms in a deep vein, most commonly in the leg.

39
Q

What is a pulmonary embolism?

A

A pulmonary embolism is caused by part of a thrombosis breaking free and travelling through the bloodstream to the pulmonary artery, where it can cause a blockage, resulting in chest pain and breathing difficulties.

40
Q

What is cholesterol?

A

A type of lipid found in the cell membrane.

41
Q

What is cholesterol used to make?

A

To make testosterone, oestrogen and progesterone .

42
Q

What May a thrombosis is an artery in the brain lead to?

A

A stroke

43
Q

What do thrombosis’ normally result in?

A

The death of some of the tissue served by the blocked artery as the cells are deprived of oxygen.

44
Q

What is peripheral vascular disease?

A

The narrowing of arteries did to atherosclerosis of arteries other than those of the heart or brain.

45
Q

What is a deep vein thrombosis?

A

A DVT is a blood clot that forms in a deep vein, most commonly in the leg.

46
Q

What is a pulmonary embolism?

A

A pulmonary embolism is caused by part of a thrombosis breaking free and traveling through the bloodstream to the pulmonary artery, where it can cause a blockage, resulting in chest pain and breathing difficulties.

47
Q

What is cholesterol?

A

Cholesterol is a type of lipid found in the cell membrane.

48
Q

State a use of cholesterol.

A

To make testosterone, oestrogen and progesterone.

49
Q

Where is 25% of the cholesterol produced?

A

In the liver

50
Q

What type of diet causes an increase in cholesterol in the blood.

A

A diet high in saturated fats or cholesterol.

51
Q

What are high density lipoproteins?

A

HDL transport excess cholesterol from the body cells to the liver for elimination.

52
Q

What are low density lipoproteins?

A

LDL transport cholesterol to body cells.

53
Q

What are LDL receptors?

A

Most cells have LDL receptors that take LDL into the cells, where it releases cholesterol.

54
Q

What happens once a cell has sufficient cholesterol?

A

A negative feedback system inhibits the synthesise of new LDL receptors and LDL circulates in the blood where it may deposit cholesterol in the arteries forming atheromas.

55
Q

What type of ratio of HDL to LDL will result in lower blood cholesterol?

A

A higher ratio of HDL to LDL

56
Q

What tends to raise HDL?

A

Regular physical activity.

57
Q

What is the name of the drugs that reduce blood cholesterol by inhibiting the synthesis of cholesterol by liver cells?

A

Statins

58
Q

What happens when there is a chronic elevation of blood glucose level due to untreated diabetes?

A

The endothelial cells lining the blood vessels take in more glucose than normal, which damages the blood vessels. This may lead to atherosclerosis leading to CVD, stroke or peripheral vascular disease.

59
Q

What monitors blood glucose concentration?

A

Receptors in the pancreas.

60
Q

Where do insulin and glucagon travel to in the blood after being produced by the pancreas?

A

To the liver.

61
Q

What happens when blood glucose concentration is raised?

A

Pancreatic receptors respond to raised blood glucose levels by increasing secretion of insulin from the pancreas.

62
Q

What does insulin do?

A

Insulin activates the conversion of glucose to glycogen in the liver, which decreases blood glucose concentration.

63
Q

What happens when blood glucose concentration is lowered?

A

Pancreatic receptors respond to lowered blood glucose levels by increasing secretion of glucagon from the pancreas.

64
Q

What does glucagon do?

A

Glucagon activates the conversion of glycogen to glucose in the liver, which increases blood glucose concentration.

65
Q

What do the adrenal glands release during exercise (or during fight or flight response)?

A

Adrenaline

66
Q

What does adrenaline do?

A

Adrenaline stimulates glucagon secretion and inhibits insulin secretion. Which increases blood glucose concentration.

67
Q

Explain type one diabetes.

A

Type 1 diabetes usually occurs in childhood. A person with type 1 diabetes is unable to produce insulin and can be treated with regular doses of insulin.

68
Q

Explain type 2 diabetes.

A

Type 2 diabetes usually develops later in life. The likelihood of developing type 2 diabetes is increased by being overweight. In type 2 diabetes, individuals produce insulin but their cells are less sensitive to it. This insulin resistance is linked to a decrease in the number of insulin receptors in the liver, leading to a failure to convert glucose to glycogen.

69
Q

What is often used as an indication of diabetes and why?

A

Glucose in the urine, as individuals with diabetes will have their blood glucose concentration increase after a meal and the kidneys will be unable to absorb all the glucose which results in glucose appearing in the urine.

70
Q

Explain the process of the glucose tolerance test.

A

Initially, the blood glucose concentration is measured after fasting. The individual then drinks a glucose solution and changes in their blood glucose concentration are measured for the next two hours. The glucose concentration of a diabetic usually starts at a higher level than that of a non-diabetic. During the test, a diabetics blood glucose concentration increases to a much higher level than a non-diabetics and takes longer to return to its starting concentration.

71
Q

What is obesity?

A

Obesity is characterised by excess fat in relation to lean body tissue such as muscle.

72
Q

What is the body mass index?

A

BMU is a measurement of body fat based on height and body mass.

73
Q

How do you calculate BMI?

A

BMI = body mass
——————
height ^2

74
Q

What BMI indicates obesity?

A

A BMI of greater than 30kgm-2

75
Q

What is wrong with BMI?

A

It can wrongly classify muscular individuals as obese.

76
Q

What can help decrease the chance of obesity?

A

Exercise and a diet limiting fats and free sugars.

Human Biology (6 decks)

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