Cardiovascular and respiratory systems Flashcards
Name the 5 structures of the conduction system
- Sino-atrial node (SA node)
- Atrio-ventricular (AV node)
- Bundle of His
- Bundle branches
- Purkyne fibres
Name the stages in the cardiac cycle
- Diastole
- Atrial systole
- Ventricular systole
Name the full cycle of the heart, including both the cardiac cycle and conduction system
- Diastole
- No electrical impulse
- Atrial systole
- SA node
- AV node
- Ventricular systole
- Bundle of His
- Bundle branches
- Purkinje fibres
Define Heart rate
the number of heart beats per minute
Define Stroke Volume
the volume of blood ejected from the left ventricle per beat
Define Cardiac output with units
the volume of blood ejected from the left ventricle per minute in l/min
Give the formula used to find cardiac output
Heart rate x stroke volume = cardiac output
Define Bradycardia
a resting heart rate below 60 bpm
Give the formula used to find maximal heart rate
Max HR = 220 - age
What’s the average cardiac output at rest?
5 l/min
Define sub-maximal exercise
exercise at a low-to-moderate intensity within a performers aerobic capacity
Define maximal exercise
exercise at a high intensity above a performers aerobic capacity
During sustained sub-maximal exercise, HR can plateau. What does this plateau represent?
represents the supply meeting demand for oxygen delivery and waste removal
Stroke volume increases in proportion to exercise intensity until a plateau is reached at approximately ___% of working capacity
40-60%
Name the reasons why stroke volume is able to increase
- increased venous return
- starling’s law
What is starling’s law?
increased venous return leads to an increased stroke volume, due to an increased stretch of the ventricle walls and therefore force of contraction
State why stroke volume reaches a plateau during sub-maximal intensity
there is not enough time for the ventricles to completely fill with blood in the diastolic phase, limiting starlings law
What regulates heart rate and determines the firing rate of the SA node
The automatic nervous system (ANS)
Name the control mechanisms of the CCC
- neural control
- intrinsic control
- hormonal control
What is this referring to? “a control centre in the medulla oblongata”
Cardiac control centre (CCC)
In the neural control, what are the 3 receptors and what do they detect?
- chemoreceptors: CO2, O2, PH levels
- baroreceptors: Blood Pressure and vasodilation/constriction
- proprioceptors: movements
What does the intrinsic control detect?
- temperature changes
- venous return
What does hormonal control detect?
levels of adrenaline and noradrenaline
What nerve does the sympathetic nervous system use?
Accelerator nerve
What nerve does the parasympathetic nervous system use?
Vagus nerve
When HR needs to increase, state which nervous system is actioned and what it does?
the sympathetic nervous system is actioned, releasing adrenaline, noradrenaline and sending stimulation to the SA node via the accelerator
When HR needs to decrease, state which nervous system is actioned and what it does?
the parasympathetic nervous system is actioned to inhibit these effects via the vagus nerve
What type of blood vessels transport oxygenated blood?
Arteries and arterioles
What type of blood vessels transport deoxygenated blood?
Veins and venules
What type of blood vessel has a wall composed of one layer of cells
capillaries
“they have a large layer of smooth muscle and elastic tissue” what blood vessel type am I referring to?
arteries
“they have a small layer of smooth muscle, and have pocket valves to prevent backflow” which blood vessel type am I referring to?
veins
Define vascular shunt mechanism
the redistribution of blood flow from one area to another
Describe the distribution of cardiac output during rest
a high percentage of cardiac output is distributed to the organs, a low percentage is distributed to the muscles
Explain what the pre-capillary sphincters do to distribute blood flow to the muscles and organs at rest
precapillary sphincters dilate, increasing blood flow to the organs, while precapillary sphincters constrict limiting blood flow to the muscles
Explain what the arterioles do to distribute blood flow to the muscles and organs at rest
arterioles to the organs vasodilate, increasing blood flow, while arterioles to the muscles vasoconstrict to limit blood flow
What happens when sympathetic stimulation increases
arterioles and pre-capillary sphincters vasoconstrict to limit blood flow
What happens when sympathetic stimulation decreases
arterioles and pre-capillary sphincters vasodilate to increase blood flow
Define Breathing rate
the number of inspirations or expirations per minute
Define Tidal volume
the volume of air inspired or expired per breath
Define Minute ventilation
the volume of air inspired or expired per minute
Give the formula that is used to find minute ventilation
Minute ventilation = breathing rate x tidal volume
Name the muscles found in between the ribs
intercostal muscles
Which 2 muscles are largely responsible for inspiration at rest and do they relax or contract
the external intercostals and the diaphragm contracts
Which 2 muscles are largely responsible for inspiration during exercise and do they relax or contract
sternodeidomastoid and pectoralis minor contracts
Which 2 muscles are largely responsible for expiration at rest and do they relax or contract
external intercostals and diaphragm relax
Which 2 muscles are largely responsible for expiration during exercise and do they relax or contract
internal intercostals and rectus abdominis contract
Describe the movements of the ribs and sternum during inspiration
up and out
Describe the movements of the ribs and sternum during expiration
out and in
What happens to the volume of thoracic cavity during inspiration
increases
What happens to the volume of thoracic cavity during expiration
decreases
What happens to the pressure in the lungs during inspiration
decreases
What happens to the pressure in the lungs during expiration
increases
Which nerve stimulates the diaphragm
phrenic nerve
Which nerve stimulates the external intercostals
intercostal nerve
What is the external site for gaseous exchange
between the alveoli and blood capillaries
What is the internal site for gaseous exchange
between the blood capillaries and muscle cells
Define the boar shift
a move in oxyhaemoglobin dissociation curve to the right caused by increased acidity in the blood stream
EQ. Compare the process of gas exchange at the muscles during exercise to resting conditions (4 marks)
- during exercise the partial pressure of O2 is lower than during rest
- the partial pressure of CO2 is higher than during rest
- the oxyhaemoglobin dissociation curve shifts to the right (the boar shift)
- the diffusion gradient is steeper
EQ. Explain how venous return mechansisms can aid venous return and prevent bood pooling (4 marks)
- valves in veins prevent backflow
- smooth muscle in blood vessels contract to push blood back to the heart
- muscle pump causes muscles in leg to contract aiding movement of blood back to the heart
- respiratory pump causes pressure difference in thoracic cavity aidning the return of blod
Name a mineral responsible for the formation of haemoglobin
iron
EQ. Explain how and why the vascular shunt mechanism redistributes blood in a cyclist as they begin cycling at the start of the even. (5 marks)
-vascular shunt mechanism redistributes blood to the working muscles that need more oxygen
-and away from the organs that need less oxygen
-using the vasomotor control
-the arterioles to the working muscles dilate
-the precapillary sphincters to the working muscles dilate
(opposite works as well for constriction at the organs)
EQ. Describe the mechanics of breathing which causes inspiration at exercise. (3 marks)
- the additional muscles sternomastoid and pectoralis minor contracts
- the ribs move upwards and outwards further
- the volume on the thoracic cavity increases more
- the pressure in the lungs decreased more
EQ. Define the term ‘stroke volume’ and give a typical resting value for a trained individual. (2 marks)
- volume of blood ejected from left ventricle in each beat
- 80-120ml
EQ. Explain the impact of regular exercise on the lifestyle diseases of coronary heart disease (CHD) and asthma. (4 marks)
CHD... -reduces levels of cholesterol in blood -prevents atherosclerosis Asthma... -increases strength of respiratory muscles -increases efficiency of gas exchange
EQ. Describe intrinsic factors that control heart rate during exercise. (2 marks)
- increased venous return
- increased stretch of the ventricular walls
EQ. Describe four mechanisms of venous return that maintain blood flow back to the heart. (4 marks)
- pocket valves prevent backflow of blood
- smooth muscle in walls of veins contract
- respiratory pump creates pressure differences in thoracic to abdominal cavity during breathing
- muscle pump where muscles contract squeezing veins and blood back to the heart
EQ. Explain why the minute ventilation of the trained individual would be lower at rest than that of the untrained individual. (3 marks)
- more efficient gas exchange at the alveoli
- more efficient transport of oxygen because of more RBCs
- more efficient use of oxyen at the muscles
EQ. Describe the role of proprioceptors in the control of tidal volume changes during exercise. (3 marks)
- proprioceptors detect increased movement in muscles
- sends signals to RCC
- increased stimulation of respiratory muscles
EQ. Describe the role of proprioceptors in the control of tidal volume changes during recovery. (2 marks)
- proprioceptors detect decreased movement in muscles
- sends signals to RCC
- reduced stimulation of respiratory muscles
EQ. Explain the term ‘excess post-exercise oxygen consumption’ (EPOC). (3 marks)
- the volume of oxygen needed to return body to pre-exercise state
- there are fast and slow components
- oxygen used to break down lactic acid
