Cardiovascular System Flashcards
(145 cards)
1
Q
What are myocytes?
A
Individual cardiac muscle cells
2
Q
What are the contractile proteins?
A
- Actin
* Myosin
3
Q
What two things are cells deprived of during cardiac arrest?
A
- Oxygen
* Glucose
4
Q
What organs are the key components of the cardiovascular system?
A
- Lungs
- Heart
- Liver
- Gut
- Kidneys
5
Q
What is the pericardium?
A
The fluid-filled sac around the heart that separates it from surrounding structures
6
Q
Which circuit does the blood that enters the right side of the heart come from?
A
The systemic circuit
7
Q
Which circuit does the blood that enters the left side of the heart come from?
A
The pulmonary circuit
8
Q
What are the structures in each of the pumps in the heart?
A
Two chambers - an upper atrium and a lower ventricle
9
Q
What do papillary muscles do?
A
They prevent inward movement of the tricuspid valve
10
Q
Which valve prevents back flow of blood into the right ventricle?
A
The pulmonary semilunar valve
11
Q
What attaches papillary muscles to both tricuspid and bicuspid valves?
A
Chordate tendinae
12
Q
Which valve prevents back flow of blood into the aorta?
A
The aortic semilunar valve
13
Q
What is the myocardium?
A
The muscular tissue of the heart
14
Q
What is diastole?
A
The period between two contractions of the heart, when the heart muscle relaxes and the chambers fill with blood
15
Q
What is atrial systole?
A
The period when the atria are contracted, forcing blood into the ventricles
16
Q
What is ventricular systole?
A
The period when the ventricles are contracting
17
Q
How long is an average cardiac cycle?
A
0.8 seconds
18
Q
How many times a minute does the average heart beat?
A
75
19
Q
What is systolic pressure?
A
The maximum pressure in the system
20
Q
What is diastolic pressure?
A
The lowest pressure in the system
21
Q
What is isovolumetric contraction?
A
The period during ventricular systole when both the atrioventricular valve and the semilunar valve are both closed and blood is trapped in the ventricles
22
Q
During the peak period of isometric contraction, what is the pressure in the left ventricle?
A
Approximately 125 mmHg
23
Q
During the peak period of isometric contraction, what is the pressure in the right ventricle?
A
25 mmHg
24
Q
What is cardiac output?
A
The volume of blood pumped out of both ventricles per minute
25
On average, what is the cardiac output when a person is at rest?
5 litres min^-1
26
What is the highest that cardiac output can be?
About 25 litres min^-1
27
What is stroke volume?
The amount of blood pumped out of the heart during one beat
28
What is the formula to calculate cardiac output?
Cardiac output = stroke volume x heart rate
29
What is diastole?
Ventricular relaxation
30
What is systole?
Ventricular contraction
31
What is a distinctive characteristic of myocytes?
They can contract and relax independently of being within the heart itself
32
What is autorhythmicity?
The ability of the heart muscle to contract without input from a nerve stimulus
33
What is the sinoatrial node?
The group of cells in the wall of the right atrium which initiate the action potential responsible for the heartbeat
34
What is the atrioventricular node?
A group of specialised heart muscle fibres at the junction between the atria and ventricles which control contraction of the ventricles
35
What are Purkinje fibres?
Modified cardiac muscle fibres which are part of the atrioventricular bundle
36
What is normal sinus rhythm?
Resting heart rate
37
Which area of the brain regulates heart function?
The medulla
38
Where do the sympathetic nerves that innervate the heart originate and how do they reach the heart?
* In the cardioacceleratory centre of the brain
| * Via the spinal cord
39
Which neurotransmitter is responsible for excitation of the heart?
Noradrenaline
40
Where do the parasympathetic nerves which innervate the heart originate and how do they travel to the heart?
* In the cardioinhibitory centre
| * Via the vagus nerve
41
Which neurotransmitter do the parasympathetic fibres of the heart use?
Acetylcholine
42
Name some of the hormones which can increase heart rate?
* Noradrenalin
* Thyroxin
* Glucagon
43
What are the 3 components of blood?
* Erythrocytes
* Leukocytes
* Plasma
44
What is the haematocrit?
The ratio of red blood cells to the total volume of blood
45
What is serum?
The the remaining fluid in a blood sample after a clot has formed
46
What is serum comprised of?
* Plasma
| * Clotting factors
47
What are the precursor cells to leukocytes, erythrocytes and platelets?
Haematopoetic stem cells
48
What is erythropoesis?
The production of erythrocytes
49
Which hormone is responsible for the production of platelets and where is that hormone produced?
* Thrombopoeitin
| * The liver
50
Which hormone is responsible for the production of erythrocytes and where is that hormone produced?
* Erythropoietin
| * Kidneys and liver
51
What are the 4 blood groups?
* A
* B
* AB
* O
52
What are agglutinogens?
The antigens expressed by erythrocytes
53
Are most people Rh-positive or Rh-negative?
Rh-positive
54
Is the production of antibodies to the Rh antigen an example of adaptive or innate immune system?
Adaptive
55
What is haemostasis?
The cascade of biomechanical reactions that lead to the cessation of bleeding
56
What are the three stages of haemostasis?
* Vascular spasm
* Platelet plug formation
* Blood clotting
57
What is vascular spasm?
Constriction of blood vessels at a wound site to slow bleeding
58
How is a platelet plug formed?
When platelets stick to the exposed collagen of a damaged blood vessel
59
What is thromboxane A2?
The hormone released by clumping platelets to further increase vasoconstriction
60
What is produced as a result of the blood clotting step of wound healing?
An insoluble fibrin mesh
61
Define the term haemorrhage
To lose a large amount of blood
62
What is elastic recoil?
The return (recoil) of the arterial wall during diastole
63
What is the formula for calculating resistance to blood flow?
Resistance = pressure gradient/blood flow
64
What is the thoroughfare channel?
A direct channel through a capillary bed
65
What are the components of plasma?
* Water
* Plasma proteins
* Nutrients
* Hormones
* Waste products
* Gases
66
What are the gases found in plasma?
* Oxygen
* Nitrogen
* Carbon dioxide
67
What nutrients are found in plasma?
* Glucose
* Amino acids
* Lipids
68
What proteins are found in plasma?
* Albumin
* Fibrinogen
* Globulins
69
What waste products are found in plasma?
* Lactic acid
| * Nitrogenous waste from protein metabolism (urea) and nucleus acids (uric acid)
70
What is pulse pressure?
The difference between systolic and diastolic pressures
71
What are also known as capacitance vessels?
Veins
72
What is the purpose of veins being in skeletal muscles?
The contraction of the muscle compresses the veins which forces blood along them
73
What is peripheral resistance?
Resistance of the systemic circulation to blood flow
74
If the diameter of the blood vessel is reduced, will the flow rate be reduced?
Yes
75
Which nervous system is responsible for the contraction of smooth muscle?
Sympathetic
76
Which nervous system is responsible for the relaxation of smooth muscle?
Parasympathetic
77
What is auto regulation?
The local control of blood flow
78
What problems can occur when blood pressure is too high?
Vessels can be damaged and fluid can leak from capillaries
79
What can happen if blood pressure is too low?
Tissues and organs will be insufficiently per fused and there may be damage or organ failure
80
When does the highest value of blood pressure occur?
During systole (ventricular contraction)
81
When does the lowest value of blood pressure occur?
During diastole (ventricular relaxation)
82
How is mean arterial pressure calculated?
Diastolic pressure + (systolic pressure - diastolic pressure) / 3
83
How is blood pressure calculated?
Cardiac output x peripheral resistance
84
What are the two factors which determine cardiac output?
* Stroke volume
| * Heart rate
85
Increasing cardiac output has what outcome?
Systolic and diastolic blood pressures are raised
86
Increasing stroke volume has what effect?
Systolic blood pressure is increased, rather than diastolic pressure
87
Peripheral resistance is largely determined by what?
The diameter of arterioles
88
What is the outcome of vasoconstriction?
Peripheral resistance increases, which causes an increase in blood pressure
89
What are baroreceptors?
Nerve endings which sense arterial blood pressure
90
Where are baroreceptors located?
In the aortic arch and the walls of the carotid arteries of the neck
91
How are baroreceptors activated?
When the arterial walls are stretched
92
What do baroreceptors do?
Detect changes in blood pressure, which is relayed to the cardioacceleratory and cardioinhibitory centres of the brain in order to influence the ANS
93
What are chemoreceptors?
Nerve endings which are sensitive to chemicals
94
What do chemoreceptors do?
Monitor levels of carbon dioxide and oxygen in the blood and are sensitive to acidity
95
What is the primary function of chemoreceptors? What else do they do?
* To regulate breathing
| * During periods of severe cardiovascular disturbance they can influence cardiac output of the cardiovascular centres
96
What is hypertension?
Elevated levels of blood pressure
97
In 2015, how many deaths, globally, were due to high blood pressure?
10.4 million
98
What are the risk factors for high blood pressure?
* Alcohol intake
* Obesity
* Diabetes mellitus
* Family history
* African/Caribbean
* Smoking
* Sedentary lifestyle
* High salt intake
* Increasing age
99
What are the complications of high blood pressure?
* Blindness
* Stroke
* Heart attack/failure
* Atherosclerosis (blood vessel damage)
* Kidney failure
100
What causes atherosclerosis?
Deposits of lipids, cellular debris and calcium salts on the inside of artery walls
101
What are the two main possible complications due to atherosclerosis?
* Infarcation
| * Ischaemia
102
What is infarction?
Death of tissue as a result of lack of blood supply
103
What is ischaemia?
Tissue damage as a result of lack of blood supply
104
What is atherosclerosis?
The degeneration of arteries through the gradual restriction of blood flow, caused by build-up of fatty material and plaque on arterial walls
105
What major blood vessels does atherosclerosis affect?
Coronary, cerebral and peripheral arteries
106
What are the types of material which atherosclerosis deposits on arterial walls?
* Lipids
* Cellular debris
* Calcium salts
107
What is the purpose of high-density lipoprotein?
To transport cholesterol from tissues to the liver
108
What is the purpose of low-density lipoprotein?
To transport cholesterol to the tissues
109
What are chylomicrons?
Droplets of fat present in blood or lymph which transport cholesterol and lipids from the lumen of the gut to the liver
110
What are statins?
Drugs to help lower cholesterol
111
How do statins work?
They inhibit production of cholesterol in the liver. This produces a gradient for low density lipoproteins to the liver, which removes their concentration in the blood
112
What is angina pectoris?
Pain caused by ischaemia in the heart muscle
113
What is myocardial infarction?
A disease state when blood flow to part of the heart is cut off. It is the main cause of heart failure
114
How do nitrovasodilators work?
* They produce nitric oxide, which is a vasodilator.
| * They reduce venous return, which reduces ventricular end-diastolic volume and active distension of the heart wall
115
How do beta blockers work?
They reduce blood pressure and peripheral resistance by blocking effects of the sympathetic nervous system
116
How do calcium antagonists work?
They reduce blood pressure and peripheral resistance by relaxation of smooth muscle in blood vessels
117
What is angioplasty?
The widening of narrowed coronary arteries by using a balloon
118
What is a stent?
A metal tube used to widen a narrowed coronary artery
119
What is one of the hormones released into the blood by necrotic tissue after a myocardial infarction?
Troponin
120
Which has more significant consequences for heart function, ventricular or atrial fibrillation?
Ventricular fibrillation
121
Define fibrillation.
It is when the heart beats in a spontaneously chaotic manner
122
Via what does blood return from the systemic circuit to the heart?
The superior and inferior vena cava
123
Via what does blood return to the heart from the systemic circuit?
The superior vena cava and inferior vena cava
124
Where does the blood pass to after the right ventricle contracts?
The pulmonary artery
125
What is the pulmonary semilunar valve?
The valve which closes when the right ventricle relaxes, preventing blood flowing back into the right ventricle
126
Via the pulmonary vein, where does blood return to?
The left atrium
127
What separates the left and right sides of the heart?
The intraventricular septum
128
What are the steps in the cardiac circuit?
Heart > Arteries > Arterioles > Capillaries > Venules > Veins > Heart
129
What are the three stages of the cardiac cycle?
* Diastole
* Arterial Systole
* Ventricular Systole
130
Which part of the nervous system controls the heart and blood vessels?
The ANS
131
Which circuit does the blood which is ejected from the left ventricle supply?
The systemic circuit
132
Which circuit does the blood which is ejected from the right ventricle supply?
The pulmonary circuit
133
What processes happen as a result of blood flow through the pulmonary circuit?
Blood taking up oxygen and releasing carbon dioxide
134
What processes happen as a result of blood flow through the systemic circuit?
Oxygen is delivered to cells and carbon dioxide is taken up
135
In an ECG, what is represented by the P waves?
Atrial depolarisation
136
In an ECG, what is represented by the PR interval?
The time taken for electrical activity to move between atria and ventricles
137
In an ECG, what is represented by the QRS complex?
The depolarisation of the ventricles
138
In an ECG, what is represented by the ST segment?
Ventricular contraction
139
In an ECG, what is represented by the QT interval?
The time taken for the ventricles to depolarise, then repolarise
140
In an ECG, what is represented by the R wave?
Ventricular depolarisation
141
In an ECG, what is represented by the T wave?
Ventricular depolarisation
142
In an ECG, what is represented by the ST segment?
If it is not a flat line, any myocardial infarction
143
What is the sinoatrial node?
A group of cells embedded in the wall of the right atrium which initiate the wave of depolarisation that causes the heart to contract
144
What is the atrioventricular node?
A group of specialised heart muscle fibres which control the contraction of the ventricles
145
Which areas of the heart are innervated by the sympathetic nervous system?
The sinoatrial and atrioventricular nodes
