1.1b Physiology Flashcards
cardiovascular and respiratory systems (69 cards)
1
Q
what are the two system in the cardiac system
A
- pulmonary ciruclation
- systemic ciruclation
blood flows through the heart twice
2
Q
what is pulmonary ciruclation
A
slow of deoxygenated blood to the lungs and oxygenated blood back to the heart
Lungs and heart flow
3
Q
what is systemic circulation
A
movement of oxygenated blood from the heart through the rest of the body and dexoygenated blood back to the heart
rest of the body and heart flow
4
Q
what are the four chambers in the heart
A
- right atrium - upper chamber recieving deoxygenated blood
- right ventricle - lower chamber containing deoxygenated blood
- left atrium - upper chamber recieving oxygenated blood from the lungs
- left ventricle - lower camber containing oxygenated blood
right ventricle and atrium is on left side of the heart and vice versa
left side of the cardiac muscle has a thicker wall to allow the heart to contract with more force on the oxygenated side
5
Q
whay are the 4 main tubes in the heart called
A
- vena cava - returns deoxygenated blood to the right atrium
- pulmonary artery - carries deoxygenated blood from the right ventricle to the lungs
- pulmonary vein - returns oxygenated blood to the left atrium from the lungs
- aorta - oxygenated blood is pumped at high pressure from the left ventricle to the rest of the body
more the efficient the heart the greater capacity to transport oxygen
6
Q
what are the 3 main valves in the heart
A
- tricuspid - prevent blood flowing back into the right atrium from the right ventricle
- bicuspid - prevent blood flowing back into th left atrium from the left ventricle
- semi-lunar - prevent blood flowing back into the ventricles
7
Q
what is the septum
A
the wall dividing the left and right sides of the heart
8
Q
define cardiac conduction system
A
a group of specialised cardiac muscle cells in the walls of the heart that send signals to the heart muscle causing it to contract
9
Q
what are the main components of the cardiac conduction system
A
- SA node
- AV node
- bundle of his
- bundle branches
- purkinje fibres
10
Q
what happens during the cardiac conduction system
A
- electrical impulse begins at the pacemaker, mass of cardiac cells called sino-atrial node (SA node)
- impulse is emmitted, spreads adjacent interconnecting fibres of the atrium causing it to contract
- then passes to another specialised mass of cells called atrioventricular node (AV node)
- AV node acts as a distributor and passes the action potential to the bundle of his
- actin potential filters into branching purkinje fibres via the bundles branches causing the ventricle to contract
11
Q
electrocardiogram
A
relationship between the electrical acitivty of the heart and the cardiac cycle
12
Q
what are the 5 key points on an electrocardiogram
A
- P-wave - depolarization of atria in response to SA node triggering
- PR interval - delay of AV node to allow filling of ventricles
- QRS complex - deplarization of ventricles, triggers main pumping contractions
- ST segment - beginning of ventricle repolarization, should be flat
- T-wave - ventricular repolarization
13
Q
what are the 2 stages to each heart beat
A
- diastole (filling) - heart filling with blood, heart is relaxing
- systole (ejection)- heart emptying, heart contracts
14
Q
what are the 4 stages to the cardiac cycle
A
- atrial diastrole - upper chamber of the heart are filled with blood returning from body via vena cava to right atrium and lungs via pulmonary vein to the left atrium
- ventricular diastrole - high pressure forces the atrio-ventricular valves open and ventricular diastrole takes place, ventricles fill with blood and semi-lunar valves remain closed, atria now contract causing atrial systole
- atrial systole - atrial contraction ensures all blood ejected into ventricles, as ventricles continue going through diastrole the pressure increases which causes atrioventricular valve to close
- ventricular systole - ventricular pressure overcomes that in the aorta and pulmonary artery, semi-lunar valves open and ventricles contract forcing blood from right ventricle into pulmonary artery and blood in left ventricle into aorta
once completed semi-lunar valves snap shut so the cycle is now complete and ready to be repeated
15
Q
short term effects of exercise on the cardiovascular
A
- increase in heart rate
- increase stroke volume
- increase cardiac output
16
Q
define cardiac output and formula
A
the amount of blood pumped out of the left ventricle of the heart per minute
stroke volume x heart rate
17
Q
define stroke volume
A
the amount of blood pumped out of the left ventricle per beat
cardiac output / heart rate
18
Q
define bradycardia
A
more O2 can be delivered to the working tissue, enabling them to work harder or for a longer period
19
Q
what is the difference between maximal and sub-maximal exercise
A
- maximal exercise - cardiac output increases significantly
- sub-maximal exercise - any activity that does not exceed 85% max HR causes cardiac output to remain unchanged whetehr trained or untrained
20
Q
bodily responses and regulation during exercise
A
anticipatory rise - increase in heart rate caused by increase in activity of the sympathetic nervous system causing adrenal glands to release adrenaline
21
Q
define venous return mechanism
A
the heart can only pump out as much blood it recieves
how blood from toes get back to the heart
- rapid increase in venous return enables significant increase in stroke volume therefore cardiac output
22
Q
what are the 4 ways venous return is overcome
A
- muscle pump - muscles surrounding the veins expand and contract pressing on the veins causing a pumping effect
- respiratory pump - muscles around the thoracic and abdominal regions cause changes in pressure, allows veins in this region to compress so blood is sucked through
- pocket valves - blood in veins can only move towards heart so cant fall back so valves at regular intervals
- gravity -
23
Q
what is frank starling mechanism
Starlings law
A
duirng exercise, venous return increases and therefore cardiac output increases. This is caused by the myocardium being stretched, resulting in myocardium contractiung with greater force
therefore stimulus that causes the greater force of contraction is the stretching of muscles fibres themselves
24
Q
the heart is myogenic, what does this mean
A
the heart generates its own impulse
25
what are the 3 mechanisms outside the heart which can alter the rate at which an impulse is fired at
1. neural control
2. intrinsic control
3. hormonal control
26
what is the CCC
the cardiac control centre in the medulla oblongata of the brain recieves three sources of information through control systems
## Footnote
* the autonomic nervous system comprises the sympathetic system and the parasympathetic system
* the sympathetic system stimulates SA node to cause the heart to beat faster or the parasympathetic system returns the heart to its resting level
27
what is the neural control mechanism
| 3 types of receptors
1. **chemoreceptors** detect an **increase in CO2 & blood acidity** send message to the CCC, this stimulates the sympathetic nerves located in the walls of blood vessels
2. **baroreceptors** (located in blood vessel walls) detect increases and decreases in **blood pressure** and send impulse to the CCC
3. **proprioreceptors** located in the muscles and **detect increase muscle movement, joint and tendon activity**
28
what is the intrinsic control mechanism
1. **Temperature** chnages in the blood will affect the thickness and the speed of nerve impulse transmission
2. **Venous return** changes will affect the stretch in the ventricle walls forcing an increase in stroke volume
29
what is the hormonal control mechanism
once stimulated, the sympathetic nerves cause the release of adrenaline and noradrenaline, these hormones will:
1. **increase heart rate**
2. constrict some blood vessels causing blood to be **redistributed** where its needed
3. stimulate the **breakdown of glycogen** providing more fuel for the muscles
30
what is vascular shunt
during exercise, blood flow to skeletal muscles increase to meet oxygen demand. **The redistribution of blood flow to areas where it is most needed**
31
define vasodilation and vasocontrisction
* **vasodilation** - ateries will increase diameter to increase blood flow, nutrients and gasesous exchnage
* **vasocontriction** - arteries will decrease diameter to decrease blood flow to certain areas
## Footnote
vessels can regulate blood pressure and ensure the tissues are recieving sufficient blood - particular during exercise
32
what is the VCC
vasometer control centre is responsible for the distribution of cardiac output.
## Footnote
* **at rest** - arterioles and pre capillary sphincters contrsitc to limit blood flow to muscles
* **during exercise** - this is reversed to deliver blood flow to working muscles
33
what are the 3 main type of blood vessels in the body
* arteries
* veins
* capillaries
34
characterisitcs of arteries
* transport oxygenated blood
* take blood away from heart
* walls are thick and elastic
* small lumen
35
characteristics of veins
* take blood to the heart
* walls are thin
* transport de-oxygenated blood
* large lumen
* has valves
36
characteristics of capillaries
* one cell thick
37
2 main functions of the respiratory system
1. pulmonary ventilation (inspiration/expiration)
2. gaseous exchange
38
what is the respiratory system pathway
nose/mouth ->trachea -> bronchi -> bronchioles -> alveoli
39
what is haemoglobin
binds with oxygen to transport it around the body in red blood cells
## Footnote
* haemoglobin transport up to four 02s
* when four 02s binded haemoglobin is fully saturated but when fewer its partially saturated
* oxygen binding occurs in response to the high PO2 in the lungs
40
define oxyhaemoglobin and deoxyhaemoglobin
* **oxyhaemoglobin** - oxygen binds to haemoglobin
* **deoxyhaemoglobin** - oxygne is not bound to haemoglobin
41
how much oxygen can combine with haemoglobin
depends on partial pressure of oxygen (PO2)
## Footnote
if PO2 is high = haemoglobin will readily combine with oxygen to form oxyhaemoglobin
42
where in the body is the PO2 low
partial pressure is low at the muscle sites. When haemoglobin releases the oxygen it is said to dissociate with oxygen
43
how is oxygen stored in the muscles
stored by myoglobin as this has a high affinity for oxygen and oxygen stores until it can be transported from the capillaries to the mitrochondria
## Footnote
once oxygen dissociates from the haemoglobin in the muscles it is picked up and transported to the mitochondria by the myoglobin
44
what is the oxygen dissociation curve
* **reveals the amount of haemoglobin saturation at different PO2 values**
* flat slope at high PO2s and steep slope at low PO2s
* S shaped curve
## Footnote
* **Lungs** - partial pressure is approximately 100mmHg at this partial pressure haemolglobin has a high affinity to O2 and is 98% saturated
* **Other tissues** - typical PO2 is 40mmHg here haemoglobin has a lower affinity for O2 and release some but not all of its O2 tissue, still abount 75% staurated
45
Factors affecting haemoglobin stauration
* decreased blood acidity
* increased blood temperature
* increased partial pressure of carbon dioxide concentration
## Footnote
these conditions decrease haemoglobins affinity for oxygen and releases more oxygen to active the muscle cells.
46
what is the Bohr shift
rightward shift of the oxygen dissociation curve
## Footnote
when exercising there is an increase in acidity this is caused by the increase in carbon dioxide in the blood, which results in an increase in the concentration of hydrogen ions in the blood lowering the pH
47
define tidal volume, its average rest value and what happens during exercise
* the volume of air inspired or expired per breath
* average at rest - 0.5 litres
* increases during exercise
48
define inspiratory reserve volume, its average rest value and what happens during exercise
* the volume able to be forcibly inspired during normal breathing
* average at rest - 3.0 litres
* decreases during exercise
49
define expiratory reserve volume, its average rest value and what happens during exercise
* volume able to forcibly expired after a normal breath
* average at rest - 1.3 litres
* small decrease during exercise
50
define residual volume, its average rest volume and chnage during exercise
* volume of air that remains in the lungs after forced maximum expiration
* average at rest - 1.2 litre
* no change
51
define minute ventilation, its average rest volume and change during exercise
* the amount of air breathed in one minute
* average at rest - 6.0 litres
* BIg increase during exercise
## Footnote
minute ventilation = tidal volume x breathing rate
52
why does depth and rate of breathing increase
1. working muscles demand oxygen
2. need to remove carbon dioxide
## Footnote
depth and rate of breathing increase in direct proportion to intensity of exercise
53
mechanics of inspiration
1. intercostal muscles contract, lifting the ribs up and out causing chest to expand
2. diaphragm contracts. It pulls down and flattens out floor of rib cage
3. lungs increase in size as chest expands
4. pressure inside lungs fall as expand.
54
muscles used during inspiration
* diaphragm
* external intercostal
* sternocleidomastoid
* pectoralis minor
55
mechanics of expiration
1. intercostal muscles relax. The ribs move down and in, chest gets smaller
2. Diaphragm relaxes, pushed back into dome position
3. lungs decrease in size as chest gets smaller, squeezed by ribs and diaphragm
4. pressure inside lungs increase as they get smaller
56
muscles used during expieration
* internal intercostals
* rectus abdominis
57
how is ventilation controlled
The respiratory control centre (RCC) located in the medulla oblongata
## Footnote
increased concentration of carbon dioxide in the blood stimulates the RCC to increase respiratory rate
58
what does the RCC do during respiration and expiration
* the **inspiratory centre** sends out **impulses via the phrenic nerve** to the inspiratory muscles
* the **expiratory centre** stimulates the expiratory muscles during exercise, when **stretch receptors detect chnages in the rate and depth of breathing**
59
During exercise, conditions in the body change. These changes are detected by:
1. **Chemoreceptors** - detect **change in pH** - blood acidity increases as a result of increase in the plasma concentration of carbon dioxide and latic acid production
2. **baroreceptors** - detect **increase in blood pressure**
3. **Proprioceptors** - detect **movement in muscles and joints**
60
what is the principle of diffusion in the lungs
gases will always move from areas of high pressure to areas of low pressure
61
what 3 gases is the atmospheric air made up of and their percentages
* Nitrogen - 79%
* Oxygen - 21%
* Carbon Dioxide - 0.03%
## Footnote
partial pressure explains the movement of gases within the body
62
62
what happens to the partial pressure of Oxygen and Carbon Diocide in the alveoli and blood
partial pressure of oxygen in alveoli is higher than partial pressure of oxgyen in the blood because oxygen has been removed from the working muscles so the concentration of oxygen is lower in the blood therefore partial pressure is lower
63
Define diffusion gradient
the difference between any two pressures
## Footnote
for example if partial pressure in alveoli is 100mmHg and partial pressure in blood is 40mmHg the diffusion gradient is 60mmHg
64
explain gasesous echnage during internal and external respiration
**internal respiration**
* oxygen diffuses from systemic capillaries into cells
* carbon dixoide diffuses from cells into systemic capillaries
**external respiration**
* carbon dixoide diffuses from pulmonary capillaries into alveoli
* oxygen diffuses from alveoli into pulmonary capillaries
65
what factors cause internal respiration to occur
* available surface area
* partial pressure gradient
* rate of blood flow varies
66
what factors cause external respiration to occur
* partial pressure of gases in alveoli differ from those in the atmosphere
* humidification of air inhaled
* gas exchange between alveoli and pulmonary capillaries
67
what promotes gaseous exchange
1. capillaries near alevoli, so shorter diffusion distance
2. large surface area, allow diffusion to take place in alevoli
3. vast network of capillaries, further increase surface area
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