Cardio-vascular System Flashcards
(90 cards)
1
Q
What is diastole?
A
Period when the ventricles and atria relax, allowing blood to flow into them
2
Q
What happens during diastole?
A
- The atria relaxes, allowing blood to flow into them and the atrioventricular valves shut, preventing blood flow into ventricles
- Pressure builds in atria and the atrioventricular valves open so blood flows into relaxed ventricles
3
Q
What is systole?
A
Period when the ventricles and atria are contracting, allowing blood to flow out of the heart
4
Q
What happens during systole?
A
- The atria contracts, allowing remaining blood to flow into ventricles
- Ventricles contract which raises the blood pressure and forces open the semilunar valves which allows blood to be forced out of the aorta and PA
5
Q
What is the definition of health?
A
A state of complete physical, mental and social well-being and not merely the absence of disease or infirmity
6
Q
What is the definition of fitness?
A
The ability to meet the demands of the environment
7
Q
What is the definition of stroke volume?
A
Amount of blood ejected from the heart per beat
8
Q
What is the definition of cardiac output?
A
Amount of blood ejected from heart per minute
9
Q
What does stroke volume depend on?
A
Venous return
Elasticity of cardiac fibres
Cardiac tissue contractility
10
Q
What is the definition of venous return?
A
The volume of blood returning to the heart via the veins - if venous return increases, SV increases
11
Q
What is meant by the elasticity of cardiac fibres?
A
The stretch of cardiac fibres during diastole
12
Q
What does Starling’s Law state?
A
The greater the venous return, the greater the stroke volume is.
13
Q
What is anticipatory rise?
A
The increase in HR is caused by increased activity of the sympathetic nervous system causing the adrenal glands to release adrenaline into the bloodstream.
14
Q
What is sub-maximal exercise?
A
Any activity that doesn’t exceed 85% max heart rate and causes CO to remain relatively unchanged
15
Q
What is maximal exercise?
A
Cardiac output increases significantly in untrained individuals.
16
Q
What is blood redistribution controlled by?
A
Th process of Vasomotor Control in the Medulla Oblongata
17
Q
What do chemoreceptors pass on to the Vasomotor centre?
A
If they detect an increase in CO2 and blood acidity
18
Q
Which nerves does the Vasomotor Centre stimulate?
A
The sympathetic nerves located in the walls of blood vessels
19
Q
What do sympathetic nerves do?
A
They cause the arterioles and pre-capillary sphincters to constrict and dilate, decreasing blood flow to non-essential areas and increasing blood flow to the working muscles
20
Q
What is the heart?
A
The heart is myogenic - generates its own impulses through its pacemaker - the SA node
21
Q
When is haemoglobin fully saturated?
A
When 4 oxygen molecules are bound to it
22
Q
When is haemoglobin partially saturated?
A
When only a few oxygen molecules are bound to it
23
Q
What does the amount of oxygen binding to haemoglobin depend on?
A
The partial pressure in the blood
If PO2 is high, oxygen will readily combine with haemoglobin
24
Q
What does myoglobin do?
A
Transports the oxygen dissociated from the haemoglobin to the mitochondria
25
What are the factors which affect haemoglobin saturation?
Decrease in blood activity
Increase in blood temperature
Increase in partial pressure of CO2 concentration
26
What is the order of the cardiac cycle?
1. The Sino-atrial node sends an impulse across the atria which stimulates them to contract
2. Diastole stage - The impulse arrives at the atrioventricular node, where it is delayed, allowing the ventricles to fill with blood
3. The impulse then travels down the bundle of His which is in the septum
4. Systole stage - The impulse travels along the Purkinje fibres which branch along the base of the right and left ventricles and cause the ventricles to contract
27
What is vascular shunt?
Controlled by the vasomotor centre in the Medulla Oblongata which alters the diameter of the arteries via the sympathetic nervous system
28
What is the SA node?
A small mass of cardiac muscle found in the wall of the RA that generates the heart beat
29
What is the AV node?
Relays the impulse between the upper and lower sections of the heart
30
What is the bundle of his?
A collection of heart muscle cells that transmit electrical impulses from the AV node via the bundle branches to ventricles
31
What are Purkinje fibres?
Muscle fibres that conduct impulses in the walls of ventricles
32
What do proprioceptors do?
Detect changes in movement and stimulate the inspiratory control centre to increase inspiration when moving
33
What do baroreceptors do?
Detect changes in blood pressure. When blood pressure drops, this initiates an increase in HR.
34
What do stretch receptors do?
Detect the stretch of the lungs which accompanies exercise and stimulates the expiratory control centre to increase expiration
35
What are pre-capillary sphincters?
They're tiny rings of muscle located at the opening of the capillaries.
36
What do pre-capillary sphincters do?
- Aids blood redistribution by constricting or dilating
- When they constrict, the blood flow is restricted through the capillary
- When they dilate, blood flow is increased
- During exercise, the capillary networks supplying skeletal muscle will be dilated to increase blood flow and saturate the tissues with oxygen.
37
What is Bohr Shift?
- The movement of the oxygen dissociation curve to the right of normal
- When exercising, there is an increase in acidity.
- This is caused by an increase in carbon dioxide in the blood, which increases the concentration of hydrogen ions in the blood, lowering the pH.
38
What are the factors responsible for Bohr shift?
Increase in blood temperature - oxygen dissociates more easily
Partial pressure of CO increases - Oxygen dissociates faster than haemoglobin
pH decreases - Oxygen dissociates faster from haemoglobin
39
What is dependent on venous return?
CO
40
What does a rapid increase in venous return result in?
A significant increase in stroke volume and therefore, cardiac output.
41
What are the 3 ways venous return can be overcome by?
1. Skeletal pump
2. Inspiration/Expiration - Respiratory pump
3. Valves
42
What is skeletal pump and how does it overcome venous return?
The muscles surrounding the veins expand and contract, pressing on veins and causing a pumping effect
Maintains venous return during exercise
43
What is the respiratory pump and how does it overcome venous return?
Muscles around the thoracic and abdominal regions cause changes in pressure
Changes in pressure allow the veins in this region to compress, causing blood to be ‘sucked’ through them
44
What are valves and how do they overcome venous return?
At regular intervals, there are semi-lunar pocket valves situated at large veins
They prevent blood from flowing away from the heart
45
What is blood pressure?
Blood pressure is defined as the force exerted by the blood against the walls of the blood vessels
It is necessary to maintain blood flow through the circulatory system
46
What is blood pressure determined by?
Cardiac Output
Resistance to flow
47
What is the equation for blood pressure?
Blood pressure = Cardiac Output x Resistance
48
How is BP measured and what by?
It is measured at the brachial artery using a sphygmomanometer and is recorded as mmHg
49
What is cardio-vascular drift?
Research has shown that HR doesn’t remain the same but increases slowly
It occurs during prolonged exercise in a warm environment despite the intensity of the exercise remaining the same.
50
What is arterial-venous oxygen difference?
The difference in the oxygen content of the arterial blood arriving at the muscles and the venous blood leaving the muscles.
51
What happens to the arterial venous oxygen difference at rest?
The arterio-venous difference is low because the muscles don’t require much oxygen.
52
What happens to the arterial-venous oxygen difference during exercise?
the muscles need more oxygen from the blood, so the arterio-venous difference is high.
53
What is tidal volume, its average value at rest and what happens during exercise?
The volume of air inspired or expired per breath
0.5 litres
Increases
54
How can the volume of air inspired or expired pe minute be calculated?
Number of breaths * Tidal volume = Minute ventilation (per min)
55
How is the total lung capacity calculated?
Adding the vital capacity of the lungs to the residual volume
56
What is tidal inspiratory reserve volume its average value at rest and what happens during exercise?
Volume of air that can be forcibly inspired after a normal breath
3.0 litres
Decrease
57
What is expiratory reserve volume, its average value at rest and what happens during exercise?
The volume of air that can be forcibly expired after a normal breath
1.3 litres
Small decrease
58
What is residual volume, its average value at rest and what happens during exercise?
Volume of air that remains in the lungs after max expiration
1.2 litres
No change
59
What is minute ventilation, its average value at rest and what happens during exercise?
The volume of air breathed in or our per minute
6.0 litres
Big increase
60
What happens in respiration?
Ventilation
External respiration
Transport of gases
Internal respiration
Cellular respiration
61
Where is the respiratory control centre located?
Medulla oblongta
62
What does the inspiratory control centre do?
controls the rate and depth of expiration
63
What does the sympathetic nervous system do?
Increases breathing rate, which helps in preparation for exercise
64
What happens within the chemical control?
Chemoreceptors detect changes in the blood pH in the aorta and medulla oblongata. They stimulate the inspiratory control centre to increase inspiration hen carbon dioxide levels increase.
65
What happens in the neutral control?
Proprioceptors – detect changes in movement and stimulate the inspiratory control centre to increase inspiration when moving
Baroreceptors – detect changes in blood pressure. When blood pressure drops, this initiates an increase in HR.
Stretch receptors – detect the stretch of the lungs which accompanies exercise and stimulates the expiratory control centre to increase expiration
66
What is partial pressure?
explains the movement of gases in the body
Pressure is measured in mmHg
67
What is the atmospheric air made up of?
Nitrogen – 79%
Oxygen – 21%
Carbon Dioxide – 0.03%
68
What is the difference between any two pressures?
Diffusion gradient
69
What is the definition of diffusion?
The net movement of particles from an area of high concentration to an area of lower concentration.
70
What is the pathway of air?
Nose/mouth
Larynx
Trachea
Bronchus
Bronchioles
Alveoli
71
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76
What happens during internal respiration?
O2 diffuses from systemic capillaries into cells
CO2 diffuses from cells into systemic capillaries
76
What 3 factors cause internal respiration to occur?
1. Available surface area, which varies in different tissues
2. Partial pressure gradient
3. The rate of blood flow varies (e.g., metabolic rate of tissue)
76
What 3 factors does external respiration depend on for it to be efficient?
1. Surface Area and structure of the respiratory membrane
2. Partial pressure gradients
3. Matching alveolar airflow to pulmonary capillary blood flow
77
What happens during external respiration?
Co2 diffuses from pulmonary capillaries into alveoli
O2 diffuses from alveoli into the pulmonary capillaries
77
What 3 factors cause external respiration to occur?
1. The partial pressure of gases in the alveoli differs from those in the atmosphere
2. Humidification of inhaled air
3. Gas exchange between alveoli and pulmonary capillaries
78
Which bodily functions is gaseous exchange promoted through?
1. Capillaries very near to alveoli, so diffusion distance is very short
2. Large SA of alveoli allows diffusion to take place
3. A vast network of capillaries surrounds alveoli which increases SA further
79
Which mechanics of breathing take place while inspiring at rest?
- The intercostal muscles contract and pull the rib cage up and out
- The diaphragm contracts causing it to flatten
- The thoracic (chest) cavity gets larger causing pressure in the lungs to decrease
- Air moves into the lungs from the higher outside pressure
80
Which mechanics of breathing take place while expiring at rest?
- The intercostal muscles relax and so the rib cage falls in
- The diaphragm relaxes pushing it up into a dome shape
- The thoracic (chest) cavity gets smaller and so the pressure in the lungs increases
- Air flows out of the lungs
81
What are the lifestyle choices that affect the respiratory system?
* Lack of exercise
* Poor diet
* Smoking
* Alcohol
82
What are the effects of smoking on the alveoli and lung function?
Alveoli can be damaged as their walls break down and join forming larger air sacs than normal, as this reduces their surface area, which makes gaseous exchange inefficient.
83
What are the effects of the carbon monoxide from smoking?
Carbon monoxide in cigarettes attaches to haemoglobin in the blood more easily than oxygen does so the blood carries less oxygen
84
What are the effects of smoking on the trachea, bronchi and cillia?
Smoking damages the cell lining of the trachea, bronchi and bronchioles. As cilia are damaged, this leads to excess mucus (smokers cough).
85
What is COPD?
COPD is a chronic obstructive pulmonary disease, it is a common lung disease which causes restricted air flow and breathing problems.
86
What are the five methods which support venous return?
The skeletal muscle pump
Pressure gradient between the thoracic and abdominal cavities forces blood through the veins
Valves
Smooth muscle
Gravity
87
What is intrapleural pressure?
Pressure in the thoracic space between the organs
The thoracic space puts pressure onto the vena cava and right atrium
