Unit 2 Cardiovascular System, Blood pressure, vessels, glucose levels. Structure of the heart, cardiac cycle, obesity and CVD. Flashcards
1
Q
In what order does the blood flow through the vessels.
A
Arteries, arterioles, capillaries, venules, veins
2
Q
What happens to the blood pressure as blood moves away from the heart.
A
Blood pressure decreases.
3
Q
What type of lining is found within the inner lining of vessels?
A
Endothelium Lining
4
Q
Describe the structure of arteries.
A
Outer layer of connective tissue containing elastic fibres, thick muscular layer containing smooth muscel and more elastic fibres. Narrow lumen
(Blood travels under high pressure)
5
Q
What is the function of elastin in the elastic walls?
A
Allows the walls of the arteries to stretch and recoil to accommodate the surge of blood after each contraction of the heart.
6
Q
What is the structure and function of the capillary?
A
Capillaries have walls which are one cell thick and allow for rapid exchange of substances within tissues.
7
Q
Describe the structure of a vein.
A
Outer layer of connective tissue with elastic fibres, Wide lumen, thin muscular smooth wall (blood travels under low pressure)
Contain valves to prevent the backflow of blood.
8
Q
Describe the process of pressure filtration that occurs at the capillary bed
A
The blood arriving at the arteriole side of the capillary bed is at a higher pressure than blood in the capillaries. As blood is forced into these narrow exchange vessels, it undergoes a form of pressure filtration and much of the plasma is squeezed through the thin walls
9
Q
What is the liquid formed when blood is forced into narrow exchange vessels of the capillary called? (After pressure filtration and plasma is squeezed out.)
A
Tissue fluid
10
Q
What is the function of tissue fluid?
A
To supply the cells with oxygen, glucose, amino acids and other substances
11
Q
Name a gas which diffuses from the capillary bed back into the blood
A
Carbon Dioxide
12
Q
What happens to the tissue fluid after the substances have diffused?
A
It returns to the blood
13
Q
Name the vessels which absorb excess tissue fluid and return the lymph fluid to the circulatory system.
A
The Lymph vessels (Lymphatic system)
14
Q
What is the cardiac output?
A
The volume of blood pumped through each ventricle per minute.
15
Q
How is the cardiac output calculated?
A
Heart beat X stroke volume (the volume of blood expelled by each ventricle on contraction. The stronger the contraction , the greater the stroke volume)
16
Q
Does the right hand side of the heart and the left hand side pump the same volume of blood through the pulmonary artery and aorta?
A
Yes
17
Q
Why does the left hand side of the heart contain a bigger muscle than the right hand side?
A
The left hand side pumps blood to the whole body where as the right hand side just pumps blood to the lungs
18
Q
What is the function of the valves in the heart?
A
To prevent backflow of blood into (depending on what valve your talking about)!
19
Q
Define diastole
A
The heart relaxing
20
Q
Define systole
A
The heart contracting
21
Q
Define atrial systole
A
The atria contracting
22
Q
Define ventricular sytole
A
The ventricles contracting
23
Q
Define atrial diastole
A
The atria relaxing
24
Q
Define ventricular diastole
A
The ventricles relaxing
25
How long approximately is 1 cardiac cycle?
0.8 seconds
26
Describe the cardiac cycle in terms of systole and diastole.
Atrial systole (ventricular diastole), Ventricular systole (atrial diastole), Atrial diastole and ventricular diastole
27
Describe what is happening to the blood during this period of dual atrial and ventricular diastole.
Blood returning to the atria is flowing into the ventricles.
28
Describe what is happening to the blood during atrial systole.
The remainder of the blood is transferred through the tricuspid/biscupid valves
29
Which valves are open during arterial systole and which ones are closed?
Tricuspid and bicuspid are open and semi-lunar are closed.
30
Which valves are open during ventricular systole?
Semilunar valves
31
Which valves are closed during ventricular systole?
Biscuspid and tricuspid valve
32
What is responsible for the sounds of the heart?
Lubb is the bicuspid closing and dupp is the semi lunar closing (in the aorta)
33
Where does the heart beat originate?
Within the heart itself but it is under both hormonal and nervous control.
34
What is the vein which enters the right atrium called?
The vena cava (deoxgenated blood)
35
What is the artery leaving the right hand side of the heart called?
The pulmonary artery (deoxygenated blood)
36
What is the vein called which enters the left hand side of the heart?
Pulmonary vein (oxygenated blood)
37
What is the artery called which leaves the left hand side of the heart?
Aorta
38
What is the artery entering the kidney called?
Renal artery
39
What is the vein called which leaves the kidney?
Renal vein
40
What is the artery called which enters the liver?
Hepatic artery
41
What is the vessel connecting the liver to the small intestine?
Hepatic portal vein
42
What is the vessel called which leaves the left hand side of the heart and goes up to the head?
The carotid arteries
43
What is the vein called which leaves the brain and goes back to the heart?
Jugular Vein
44
What are the vessels called which supply the heart with its own supply of glucose and oxygen?
Coronary arteries
45
Does the right hand side of the heart and the left hand side pump the same volume of blood through the pulmonary artery and aorta?
Yes
46
What is responsible for closing the AV valves?
The higher pressure in the ventricles slams shut the AV valves
47
What is the SAN?
The sino atrial node which sets the rate of the heart beat
48
How does the SAN work?
The autorythimic cells contract simultaneously. A wave of excitation spreads across the atria making them contract.
49
Which part of the brain regulates the rate of the SAN
Medulla
50
Which part of the nervous system has control of the heart
The autonomic nervous system
51
What does the sympathetic accelerator system do?
The sympathetic nerves release the hormone nor-adrenaline and speed up the heart rate
52
What does the para- sympathetic accelerator system do?
The para-sympatheic nerves acetylcholine which slows down the heart rate
53
What receives the impulse as it spreads through the atria?
The atrioventricular node
54
What happens when the atrioventricular node receives the nerve impulse?
It is passed on to bundles of fibres which spread around the walls of the ventricles causing them to contract simultaneously.
55
What is performed to detect the impulses spreading throughout the heart?
An ECG
56
How does a sphygmomanometer work? (Blood pressure cuff)
It stops blood flow and deflates gradually. The blood starts to flow (detected by pulse) at systolic pressure
57
What is systolic pressure?
The pressure detected when the heart contracts
| Pressure it takes to stop the blood flow
58
What is diastolic pressure?
When heart is relaxing
| Pressure to allow free flow of blood in artery
59
What is a typical reading of a young adult?
120/70 mmHg
60
How is blood pressure written?
Systolic/diastolic
61
Why does the blood pressure drop as it passes from the heart throughout the body?
Peripheral resistance – As blood flows through the vessels, more blood comes into contact with the vessel walls which causes friction and reduces the flow of blood.
62
What can high blood pressure lead to?
It is a major risk factor for coronary heart disease. Oedema can also become an issue (severe swelling).
63
What is atherosclerosis?
Atherosclerosis is the accumulation of fatty material (consisting mainly of cholesterol), fibrous material and calcium forming an atheroma or plaque beneath the endothelium.
64
What happens to the artery as the atheroma (Fatty accumulation) grows?
As the atheroma grows the artery thickens and loses its elasticity. The diameter of the artery becomes reduced and blood flow becomes restricted resulting in increased blood pressure.
65
Athersclerosis is said to be the root cause of what?
Atherosclerosis is the root cause of various cardio vascular diseases including angina, heart attack, stroke and peripheral vascular disease
66
What happens to the endothelium if the atheroma ruptures?
It becomes damaged
67
What is the result of the endothelium becoming damaged due to a ruptured atheroma?
Damage releases clotting factors that activate a cascade of reactions resulting in the conversion of the enzyme prothrombin to its active form thrombin.
68
Describe the process of Thrombosis
Damage releases clotting factors that activate a cascade of reactions resulting in the conversion of the enzyme prothrombin to its active form thrombin.
thrombin then causes molecules of the plasma protein fibrinogen to form threads of fibrin.
Fibrin threads form a meshwork that clots the blood, seals the wound and provides a scaffold for the formation of scar tissue.
69
Define Thrombosis.
The formation of a blood clot
70
Can a thrombus become dislodged?
In some cases a thrombus may break loose forming an embolus and travel through the bloodstream until it blocks a blood vessel.
71
When can happen if a thrombus is found in a coronary artery?
May lead to a heart attack
72
What can happen if a thrombus is found in an artery in the brain?
A thrombosis in an artery in the brain may lead to a stroke.
73
What happens to the tissues if they are deprived of oxygen?
Death of the tissues.
74
What is peripheral vascular disease?
Peripheral vascular disease is narrowing of the arteries due to atherosclerosis of arteries other than those of the heart or brain.
75
Which limb is usually affected by peripheral vascular disease?
The legs
76
What is pain in the legs due to peripheral vascular disease caused by?
A limited supply of oxygen
77
What is Deep Vein Thrombosis?
DVT is a blood clot that forms in a deep vein most commonly in the leg, and can break off and result in a pulmonary embolism.
78
Where is cholesterol produced?
Cholesterol is synthesised by all cells, although 25% of total production takes place in the liver.
79
What does a diet high in saturated fats or cholesterol cause?
A diet high in saturated fats or cholesterol causes an increase in cholesterol levels in the blood.
80
What is cholesterol a component off?
cholesterol is a component of cell membranes and a precursor for steroid synthesis
81
What does HDL transport and what does this prevent?
HDL transports excess cholesterol from the body cells to the liver for elimination. This prevents accumulation of cholesterol in the blood.
82
What does LDL transport?
LDL transports cholesterol to body cells.
83
What receptors do most cells have?
Most cells have LDL receptors that take LDL into the cell where it releases cholesterol
84
What happens once a cell has sufficient cholesterol?
Once a cell has sufficient cholesterol a negative feedback system inhibits the synthesis of new LDL receptors and LDL circulates in the blood where it may deposit cholesterol in the arteries forming atheromas.
85
What happens if you have a higher HDL to LDL ratio?
A higher ratio of HDL to LDL will result in lower blood cholesterol and a reduced chance of atherosclerosis.
86
What does regular physical activity do to HDL levels?
Regular physical activity tends to raise HDL levels.
87
Why diatary changes can people make to support a healthier lifestyle with regard to cholesterol?
Dietary changes aim to reduce the levels of total fat in the diet and to replace saturated with unsaturated fats.
88
Name the drugs that reduce blood cholesterol by inhibiting the synthesis of cholesterol by liver cells.
Statins
89
What gene predisposes individuals to developing high levels of cholesterol?
Familial hypercholesterolaemia (FH) due to an autosomal dominant gene
90
What is the impact of the Familial hypercholesterolaemia (FH) gene?
Reduced number of LDL receptors or an altered receptor structure
91
What can be done to detect Familial hypercholesterolaemia gene and what treatment can be offered?
Genetic testing can determine if the FH gene has been inherited and it can be treated with lifestyle modification and drugs.
92
What is the effect of chronic elevation of blood glucose levels on blood vessels? Explain how this happens.
chronic elevation of blood glucose levels leads to the endothelium cells taking in more glucose than normal damaging the blood vessels
93
What can atherosclerosis cause?
Atherosclerosis may develop leading to cardio vascular disease, stroke or peripheral vascular disease.
94
If small blood vessels become damaged because of elevated blood glucose levels, what can happen?
small blood vessels damaged by elevated glucose levels may result in haemorrhage of blood vessels in the retina, renal failure or peripheral nerve dysfunction.
95
How do pancreatic receptors respond when they detect high levels of glucose?
Pancreatic receptors respond to high blood glucose levels by causing secretion of insulin.
96
What does Insulin activate in the liver?
Insulin activates the conversion of glucose to glycogen in the liver decreasing blood glucose concentration
97
How do pancreatic receptors respond to low glucose levels?
Pancreatic receptors respond to low blood glucose levels by producing glucagon.
98
What does Glucagon activate in the liver?
Glucagon activates the conversion of glycogen to glucose in the liver increasing blood glucose level.
99
What happens to the glucose levels during exercise and the fight or flight response?
during exercise and fight or flight responses glucose levels are raised.
100
What is this elevated blood glucose levels during the flight of flight response caused by?
Adrenaline (epinephrine) is released from the adrenal glands stimulating glucagon secretion and inhibiting insulin secretion.
101
What can vascular disease be a complication of?
Diabetes
102
When does Type 1 diabetes usually occur?
Childhood
103
When does Type 2 Diabetes usually occur?
Type 2 diabetes or adult onset diabetes typically develops later in life and occurs mainly in overweight individuals.
104
Why is a person described as having Type 1 diabetes?
People with type 1 diabetes are unable to produce insulin and can be treated with regular doses of insulin.
105
Why is a person described as having Type 2 diabetes?
Type 2 diabetes individuals produce insulin but their cells are less sensitive to it.
106
What is insulin resistance linked to?
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.
107
Why is glucose lost in the urine in both types of diabetes?
in both types of diabetes, individual blood glucose levels will rise rapidly after a meal and the kidneys are unable to cope resulting in glucose being lost in the urine.
108
What two tests can a doctor perform to indicate diabetes?
Testing urine for glucose is often used as an indicator of diabetes. A glucose tolerance test is used to diagnose diabetes.
109
When are glucose levels of a suspected diabetic sufferer measured?
The blood glucose levels of the individual are measured after fasting and two hours after drinking 250–300 ml of glucose solution
110
What is obesity a major risk factor for?
Obesity is a major risk factor for cardiovascular disease and type 2 diabetes.
111
What is obesity characterised by?
By excess body fat in relation to lean body tissue (muscle).
112
You are said to be obese if you have a BMI of over what?
A body mass index (weight divided by height squared) greater than 30 is used to indicate obesity.
113
How do you calculate BMI?
weight divided by height squared
114
What is required to be measured to get an accurate measurement of body fat?
Requires the measurement of body density.
115
What lifestyle factors is obesity linked too?
High fat diet and a decrease in physical activity
116
Energy intake in the diet should limit what?
Fats and free sugars as fats have a high calorific value per gram and free sugars require no metabolic energy to be expended in their digestion.
117
What does exercise increase and preserve?
Exercise increases energy expenditure and preserves lean tissue.
118
How can exercise help reduce risk factors for CVD?
By keeping weight under control, minimising stress, reducing hypertension and improving HDL blood lipid profiles.
