Anatomy and physiology Flashcards
(133 cards)
1
Q
How does blood flow through the right side of the heart?
A
(deoxygenated blood)
Vena cava / Right atrium / Tricuspid valve / Right ventricle / Pulmonary artery
2
Q
How does blood flow through the left side of the heart?
A
(oxygenated blood)
Pulmonary vein / Left atrium / Bicuspid valve / Left ventricle / Semi lunar valve / Aorta
3
Q
What side of the heart is larger and has thicker walls?
A
Left side as blood travels a further distance so has to be pumped with more force.
4
Q
What are the heart’s main 3 roles?
A
- Deliver oxygen to working muscles
- Remove waste products
- Transports heat to the surface of the skin
5
Q
What is the cardiac conduction system?
A
A group of specialised cells located in the wall of the heart which send electrical impulses to the cardiac muscle, causing it to contract.
6
Q
How does current flow in the cardiac conduction system?
A
SAN / AVN / Bundle of His / Purkinje fibres /
7
Q
What is the location and role of the SAN?
A
Located in the walls of atria
The heart’s pacemaker, creates wave of excitation.
8
Q
What is the location and role of the AVN?
A
Located in the atrioventricular septum
Delays impulse for 0.1 seconds so atria can contract fully before ventricular systole.
9
Q
What is the location and role of the Bundle of His?
A
Located in septum
Transmits electrical impulses through branches
10
Q
What is the location and role of the Purkinje fibres?
A
Network of muscle fibres spread throughout ventricles
Cause ventricular systole.
11
Q
State the 3 components of the nervous system:
A
- Central nervous system
- Peripheral nervous system
- Autonomic nervous system
12
Q
What is the role of the autonomic nervous system?
A
Subconsciously alters timings of heart.
13
Q
Sympathetic neurons…
A
Increase HR
14
Q
Parasympathetic neurons…
A
Decrease HR
15
Q
What is the role of the Medulla oblongata?
A
Regulates several basic functions of the autonomic nervous system.
Cardiac control centre in the medulla oblongata controls sympathetic and parasympathetic systems.
16
Q
Where are baroreceptors located and what do they detect?
A
Located in arterial walls of heart.
Detect change in blood pressure.
17
Q
If blood pressure is too high…
A
- Baroreceptors detect artery wall is stretched, impulse is sent to medulla oblongata, impulse is sent down parasympathetic neurones to SAN, HR decreases, BP decreases
18
Q
Where are chemoreceptors located and what do they detect?
A
Located in the blood
Detect changes in blood pH
19
Q
If CO₂ concentration is too high…
A
Chemoreceptors detect increase in blood acidity, impulse sent to medulla oblongata, impulse is sent to SAN down sympathetic neurones, HR increases, CO₂ concentration decreases
20
Q
Where are proprioceptors located and what do they detect?
A
Located in skin, muscle spindles, and tendons.
Detect changes in movement in limbs, muscles and joints.
21
Q
If movement increases…
A
Proprioceptors detect increase in movement, impulse sent to medulla oblongata, impulse sent to SAN down sympathetic neurones, HR increases, Cardiac output increases and more oxygen is delivered to working muscles.
22
Q
What is adrenaline and what is it’s role?
A
A stress hormone
Increases arousal and causes an anticipatory rise in heart rate.
23
Q
How does adrenaline work?
A
- Adrenaline is released by adrenal glands in time of stress, adrenaline stimulates the SAN, mimicking the sympathetic nervous system
24
Q
What is stroke volume?
A
The volume of blood pumped out by the heart ventricles per contraction.
25
What is the average resting stroke volume?
70ml
26
What 3 things affect stroke volume?
1. Venous return
2. Elasticity of cardiac fibres during diastole phase.
3. Contractility of cardiac tissue.
27
What is venous return?
The volume of blood that returns to the heart after each contraction.
28
What is ejection fraction?
The percentage of blood that is pumped out by the left ventricle per beat.
29
What is the average resting and working ejection fraction?
Resting = 60%
Working = 85%
30
What is cardiac output?
The volume of blood pumped out by the heart ventricles per minute.
31
How does stroke volume change during high intensity exercise?
- Initial increase
- Once athlete is working beyond 40-60% of max intensity, SV plateaus.
- Because high HR = short diastole phase = not enough time for ventricles to fill = lower venous return = less blood pumped out
32
What does Starling's law state?
Increased venous return causes greater diastolic filling of the heart, increasing the elasticity of cardiac fibres. This causes a greater force of contraction, increasing ejection fraction and stroke volume.
33
How to calculate Cardiac output
Q = SV x HR
(Average = 70 x 72 = 5040ml)
34
What is cardiac hypertrophy?
The thickening of the muscular wall of the heart.
35
What is bradycardia?
A resting heart rate below 60bpm.
36
Why is bradycardia common in elite athletes?
Cardiac hypertrophy causes a greater stroke volume.
37
How does heart rate respond to exercise?
- Anticipatory rise prior exercise
- Sharp, anaerobic rise
- Further rise
- Steady state
- Rapid decline post exercise
- Slower recovery
38
What is heart disease?
Blockage in - or narrowing of -the the coronary arteries due to a gradual build up of atheroma (fatty deposits).
39
What is a build up of atheroma called?
Atherosclerosis
40
What is atherosclerosis caused by? (4)
1. High BP
2. High cholesterol
3. Lack of exercise
4. Smoking
41
What is angina?
Chest pain caused by the narrowing of the coronary arteries as the heart receives a lack of oxygen.
42
When do heart attacks occur?
When a piece of atheroma breaks off in the artery, causing a blood clot that blocks off the supply of oxygenated blood to the heart.
43
What is blood pressure?
The force exerted by the blood against the blood vessel wall.
44
How do you calculate blood pressure?
BP = blood flow x resistance
45
Impacts of high blood pressure
Excess strain on the arteries can increase the risk of heart attacks, heart failure, kidney disease, strokes, and dementia.
46
What is LDL cholesterol?
Low density lipoproteins - transport cholesterol in the blood to tissues. Bad as they cause arteries to narrow.
47
What is HDL cholesterol?
High density lipoproteins - transport excess cholesterol in the blood back to liver to be broken down. Good as they remove LDL from arteries.
48
When do strokes occur?
When blood supply to the brain is cut off, damaging the brain cells.
49
What are ischemic strokes?
Caused by a blood clot blocking flow of blood to brain (most common)
50
What are haemorragic strokes?
Caused when a blood vessel that supplies the brain bursts.
51
What is cardiovascular drift?
An increase in heart rate during prolonged exercise. Happens because fluid is lost as sweat, causing plasma volume and therefore stroke volume to decrease.
This causes venous return to decrease and cardiac output to increase as more energy is needed to cool the body.
52
How does blood move through the vascular system from and to the heart?
Heart - arteries - arterioles - capillaries - venules - veins - heart.
53
What is the pulmonary cycle?
Flow of deoxygenated blood from the heart to the lungs and oxygenated blood from the lungs back to the heart.
54
What is the systemic system?
Flow of oxygenated blood from the heart to the body and deoxygenated blood from the body back to the heart.
55
What is systolic BP?
Pressure in arteries when ventricles contract.
56
What is diastolic BP?
Pressure in the arteries when ventricles relax between contractions.
57
Where is BP measured?
At the brachial artery in the upper arm.
58
What is the average blood pressure at rest?
120/80 mmHg
59
What is blood pressure largely dependent on?
The distance of the blood vessel from the heart
The type of blood vessel.
60
Why are mechanisms needed to pump blood back to the heart?
Blood is carried under low pressure in the veins.
61
What are the 3 main venous return mechanisms?
Skeletal muscle pump
Respiratory pump
Pocket valves
62
What are the 3 other venous return mechanisms?
Thin layer of smooth muscle in the walls of the veins.
Gravity helps blood enter superior vena cava
Suction pump action of heart
63
What is the skeletal muscle pump?
Muscles contract and compress nearby veins, squeezing blood towards the heart.
64
What is the respiratory pump?
muscles contract and relax when inhaling and exhaling. This creates pressure changes in the thoracic and abdominal cavities, compressing nearby veins and squeezing blood towards the heart.
65
What are pocket valves?
Ensure one-way flow of blood, prevent back flow of blood. Valves open when the muscle contracts and close when the muscle relaxes.
66
How does venous return change during exercise?
Oxygen demands increase.
Skeletal muscles are constantly working and breathing is elevated.
Skeletal and respiratory pump maintain venous return.
Both mechanisms need to be maintained after exercise
Active cool downs prevent blood pooling
67
What is venous return determined by?
A pressure gradient
68
What is mean systemic pressure?
The mean pressure in the circulatory system after blood has been distributed evenly.
69
What do peripheral veins do?
Lead deoxygenated blood from the capillaries back to the heart.
70
What is vascular resistance?
The resistance that must be overcome to push blood through the circulatory system.
71
What is the formula for calculating venous return?
VR = (Pv - Pra) / Rv
(venous pressure - right atrial pressure) / venous vascular resistance
72
How many oxygen molecules do saturated hemoglobin molecules carry?
4
73
Where is myoglobin found and what is its function?
Stores oxygen in slow twitch muscle fibres.
74
What is oxyhaemoglobin dissociation?
The diffusion of oxygen from a high concentration in the oxyhaemoglobin to a low concentration in the tissues.
75
What is oxygen saturation at the lungs and why?
Approx. 100% because gas exchange has just occurred.
76
What happens as partial pressure of oxygen increases?
Oxygen percentage saturation increases.
77
What percentage of haemoglobin's oxygen is given to the muscles at rest?
23%
78
What is Bohr shift?
During exercise dissociation of oxygen occurs more readily and the S-shape of the graph shifts to the right.
79
What 3 factors cause Bohr shift?
More CO2 in blood (decreased pH increases diffusion)
Increase in temperature (vasodilation)
Increased partial pressure of CO2 (more CO2)
80
What is the vascular shunt mechanism?
the redirecting of blood flow to areas where it is most needed.
81
Why does vasodilation occur when exercising?
To redirect blood flow to working muscles.
82
How does an increase in sympathetic nerve impulses affect blood flow?
Vasoconstriction occurs, reducing blood flow so it can be redistributed.
83
What are pre-capillary sphincters?
Rings of muscle located at the opening of the capillaries.
Contract / relax to restrict / increase blood flow
84
What is arterio-venous difference?
The difference between the oxygen content of the arterial blood arriving at the muscles and the venous blood leaving the muscles.
85
What is the role of the nasal cavity?
Hairs filter pollen and dust in the air.
Air is warmed and moistened.
86
What is the role of the epiglottis?
Flap of cartilage which closes when eating to prevent food entering trachea.
87
What is the role of the pharynx?
Connects nasal cavity to larynx
Passageway for air and food
88
What is the role of the larynx?
Connects pharynx to trachea, vocal chords
89
What is the role of the trachea?
Rings of cartilage, strong and flexible passageway for air.
90
What is the role of the bronchus?
Carries air to lungs
91
What is the role of the bronchioles?
Small airways that carry air to the alveoli
92
How many lobes are on each lung and what is their role?
3 on right, 2 on left
Allow air to be drawn into body
93
What is the role of the alveoli?
Gas exchange between lungs and blood, large surface area, one cell thick, extensive capillary network.
94
What is the role of the diaphragm?
Flat muscle beneath lungs, mechanisms of breathing, flattens when inhaling
95
What is the role of pleura?
Fluid filled membrane that surrounds each lung to reduce friction.
96
What is the difference between visceral and parietal pleura?
Parietal = outer lining
Visceral = inner lining
97
What is the role of the internal intercostal muscles?
Inside rib cage, contract during expiration.
98
What is the role of the external intercostal muscles?
Outside rib cage, contract during inspiration.
99
What is pulmonary ventilation?
The exchange of air between the lungs and the atmosphere.
100
What are the 6 mechanisms of breathing when inspiring at rest?
Air enters actively
1. Diaphragm contracts and
flattens
2. External intercostal muscles contract
3. Rib cage moves upwards and outwards
4. Volume of thoracic cavity increases
5. Decrease in lung pressure
101
What are the 6 mechanisms of breathing when expiring at rest?
Air leaves passively
1. Diaphragm relaxes and curves upwards
2. Internal intercostal muscles contract
3. Rib cage moves downwards and inwards
4. Volume of thoracic cavity decreases
5. Increase in lung pressure
102
What are the additional mechanisms of breathing when inspiring during exercise?
- Minor muscles contract to increase the speed and force of inspiration.
- Thoracic cavity expands to a larger size, more air able to enter.
103
What are the additional mechanisms of breathing when expiring during exercise?
- Obliques and rectus abdominals contract to expell air out.
- Thoracic cavity decreases in volume rapidly
- Air rushes out the lungs actively
104
What is tidal volume?
The amount of air inhaled or exhaled with each normal breath
105
What is the average tidal volume?
0.5l
106
What is minute ventilation?
The amount of air inhaled or exhaled per minute (BPM x TV)
107
What is total capacity?
Lung volume following a maximal inspiration
108
What is vital capacity?
The amount of use-able lung space (total capacity - reserve volume)
109
What is reserve volume?
The maximum amount of air that can be taken into / forced out of the lungs after a normal breath.
110
What is residual volume?
The amount of air left in the lungs after a maximal expiration
111
Why is having a residual lung volume important?
The lungs are always kept partially inflated to protect microscopic structures from damage.
112
How are lung volumes measured?
Spirometers display data as a spirometry trace.
113
Why do tidal volumes and breathing rates have a lag time during HIIT?
Will likely peak at rest as it takes time for receptors to detect changes and relay information.
114
What is partial pressure?
The force exerted by a gas within an environment.
115
Partial pressure of gas exchange during exercise (5)
- Larger diffusion gradient
- Capillaries, short diffusion distance
- Red blood cells travel single file
- Extensive capillary network
- Myoglobin has a higher affinity for oxygen
116
What is the RCC responsible for?
Altering pulmonary ventilation
117
What happens in the expiratory control centre?
- Impulses sent down intercostal nerve
- Abdominals and internal intercostals contract, forced expiration
- Stretch receptors detect maximum inflation
- Stimulates the ECC
118
What is the Hering - Breur Reflex?
Stretch receptors detect max inflation, stimulating ECC to initiate active expiration
119
What happens in the inspiratory control centre?
- Impulses sent down phrenic nerve
- Contraction force and frequency increases of the : diaphragm, external intercostals, sternocleidomastoid and pectorals minor.
- ECC is activated
- Responsible for both inspiration and expiration
120
What is the role of neurons?
Deliver action potential to respiratory muscles
121
What is the role of dorsal respiratory group neurons?
Increase depth of breathing to utilise more reserve volumes
122
What is the role of ventral respiratory group neurons?
Control the frequency of contractions
123
What is slight hypoxia?
When oxygen in the blood and muscles depletes faster than the resting rate of retrieval in the lungs.
124
How do the adrenal glands control breathing?
Detect slight hypoxia - Secrete adrenaline within the SNS - transmissions sent faster with greater action potential - increased pulmonary ventilation counteracts hpoxia
125
How do chemoreceptors control breathing?
Hypoxia causes blood acidity to increase - chemoreceptors detect increase - transmissions sent down SNS
126
Recommendations for physical activity
adults - 30 mins 5 days a week
children - 1 hour a day
127
What are 3 benefits of exercise?
- muscle hypertrophy
- improved metabolism
- improved cardiovascular fitness
128
What are 4 negatives of inactivity?
- CHD
- Obesity
- Diabetes
- NHS costs
129
Why do stress responses occur?
A release of adrenaline and cortisol
130
Why are stress hormones damaging to health?
Elevate breathing rate outside of exercise, placing unnecessary stress on respiratory mechanisms.
Prolonged high blood pressure
131
Impacts of a poor work - life balance:
Unhealthy stress responses
CHD
Diabetes
Obesity
Skin conditions
Migrane
High blood pressure
132
Negatives of smoking
Damages coronary heart vessels
Increased risk of CHD
Lung cancer
CO attaches to haemoglobin, restricting oxygen transport
Airways narrow due to inflammation of walls and lining.
133
Negative impact of cholesterol build up on oxygen transport
Higher blood pressure, faster blood, less opportunity for oxygen to diffuse, reduced cardiac output.
