1.1 The Cardiovascular System Flashcards
List 5 ways exercising and being fit improves your physical health.
- increased metabolism
- increased stroke volume
- decrease in resting heart rate
- cardiovascular/ respiratory improvement
- develop more red blood cells (more oxygen can be taken to working muscles)
Describe the pathway of blood in the heart.
- Venae Cavae (Superior and Inferior) - brings deoxygenated blood
- Right atrium
- tricuspid valve
- right ventricle
- pulmonary semilunar valves
- pulmonary artery
- lungs
- Pulmonary vein
- Left atrium
- bicuspid valve
- left ventricle
- aortic semilunar valve
- aorta
- body
List 4 differences between being trained and untrained.
- increase in red blood cells and haemoglobin (can be done through training at high altitudes or an altitude tent)
- trained athletes go through cardiac hypertrophy
- this leads to them having an increase in stroke volume (both at rest and whilst exercising) and therefore lower HR
- allows them to return to their resting HR quicker.
How does the cardiac conduction system work?
- sinoatrial node (SAN)
- atrial systole
- Atrioventricular node (AVN)
- bundle of his
- bundle of branches
- purkinje fibers
- ventricular systole
define fitness
the ability to meet and cope with the demands of the environment
define health
state of complete physical, mental and social well-being and not merely the absence of disease/ infirmity/ injury.
define diastole
relaxation phase in the cardiac cycle
define systole
describes the contraction phase of the cardiac cycle
define anticipatory rise
slight increase in HR usually before activity starts due to the expectation of exercise.
define stroke volume
volume of blood that leaves the heart during each contraction (untrained average volume: 70ml + trained average volume: 150-180ml)
define cardiac output
volume of blood the heart pumps out per minute (untrained person at rest: 5.6 L/min)
What?Where?When? - Diastole phase
What: the heart is relaxing and filling with blood.
Where: atria fills with blood (pressure builds)
When: as pressure increase, valves open, letting small amounts of blood through.
What?Where?When? - Systole phase
Atrial systole:
valves are forced open, both atrial contract, remaining blood forced into ventricles
Ventricular systole:
ventricles contract (increasing pressure)
aortic semilunar valve opens
blood is forced out
define Heart Rate
number of beats per minute (average for males: 70 bpm and females: 72 bpm)
What is the equation for cardiac output
SV x HR
Short term effects of exercise
- increased HR (due to rise in adrenaline levels)
- increase in cardiac output
- increase in stroke volume (due to stronger ventricular contractions)
Long term effects of exercise
- decrease in resting HR
- thicker left ventricular wall
- increase in resting stroke volume
- hypertrophy of the heart
- improvement in cardiac output during exercise
- increased number of capillaries in muscles (more efficient oxygen delivery to muscles)
- increase in blood volume (increase in red blood cells to carry oxygen)
Explain the points A-F on the maximal vs submaximal heart rate graph.
A = anticipatory rise - hormonal action of adrenaline that causes the Sinoatrial node (SAN) to increase the HR B = sharp rise in HR mainly due to anaerobic work C = HR continues to rise due to maximal workloads stressing the anaerobic system D = steady state - athlete is able to meet oxygen demand with oxygen supply E = rapid decline in HR as soon as exercise stops (rapid recovery) F = body returns to resting levels, HR needs to stay elevated to remove waste products such as lactic acid ( therefore this is the slower recovery)
What is part of the neural control system?
Specify what they do.
Sympathetic nervous system - stimulates the heart to beat faster
Parasympathetic system - returns the heart to its resting level
Medulla oblongata - is the cardiac control centre
how does chemoreceptors cause a change in heart rate?
- they detect an increase in Carbon dioxide
- causing the stimulation of the sympathetic nervous system
- causing the heart to beat faster
How does Baroreceptors cause a change in heart rate?
- detects an increase in blood pressure (specifically at the arterial wall)
- sends a signal to the medulla oblongata
- an increase in BP causes an increase in the stretch of the baroreceptor resulting in the decrease of HR
- if there is a decrease in BP there will be a decrease in the stretch of the baroreceptor causing an increase in HR
How does Proprioceptors cause a change in heart rate?
- located in muscles
- detect increase in muscle movement
- receptor sends an impulse to the medulla oblongata
- this then sends an impulse through the sympathetic nervous system to the SAN to increase HR
- when the parasympathetic system stimulates the SAN, it decreases the HR
What is the hormonal control mechanism ?
the release of adrenaline during exercise
it increases cardiac output
results in more blood being pumped to the working muscles
they receive more oxygen for the energy they need
define myogenic
capacity of the heart to generate its own impulses
define sinoatrial node
small mass of cardiac muscle found in wall of right atrium that generates the heart beat
define Atrioventricular node
this node relays the impulse between the upper and lower sections of the heart
define bundle of his
collection of heart muscle cells that transmit electrical impulses from the AVN via the bundle branches to the ventricles
What are the two chambers divided by in the heart?
the interventricular septum
Why do ventricles have thicker muscular walls compared to the atria?
- because they need to be able to contract a much greater force in order to push the blood out of the heart
- specifically the left side as it needs to get around the whole body, whereas, the left side only needs to get the deoxygenated blood to the lungs which are in close proximity to the heart.
What are two factors that affect the rate of the conduction system?
- neural control mechanism - medulla oblongata
2. hormonal control mechanism - adrenaline
What effect does adrenaline have on the hormonal control mechanism?
- it is a stress hormone released by sympathetic nerves and the cardiac nerve during exercise
- it stimulates SAN –> increasing the speed and force of contractions
- increases cardiac output
therefore increases amount of oxygenated blood that gets to working muscles for energy
What three things does stroke volume depend on?
- Venous return: (this is the volume of blood that returns to the heart via the veins) if it increases then the stroke volume will also increase.
- Elasticity of cardiac fibres (the degree of stretch of cardiac tissue during the diastole phase of the cardiac cycle - greater the stretch = greater the contraction)
- Myocardium (contractility of cardiac tissue) - greater the myocardium = greater the contraction –> increase in SV
define the sympathetic system
part of the autonomic nervous system that speeds up heart rate
define the parasympathetic system
part of the autonomic nervous system that decreases heart rate