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Cardiovascular system at rest and in exercise - Coggle Diagram
Cardiovascular system at rest and in exercise
Myles
Heart rate Heart rate (HR) is the number of times the heart beats in one minute. The average number of beats is 72 beats per minute.
You can calculate your maximum heart rate by subtracting your age from 220. For example, if you're 45 years old, subtract 45 from 220 to get a maximum heart rate of 175. This is the average maximum number of times your heart should beat per minute during exercise.
Heart rate is measured in beats per minute (bpm). During exercise the heart rate increases so that sufficient blood is taken to the working muscles to provide them with enough nutrients and oxygen. An increase in heart rate also allows for waste products to be removed
Stroke volume (SV) is the volume of blood pumped out of the heart with every beat. The average amount of blood per beat is 0.07 litres.
Calculation. Its value is obtained by subtracting end-systolic volume (ESV) from end-diastolic volume (EDV) for a given ventricle. In a healthy 70-kg man, ESV is approximately 50 mL and EDV is approximately 120mL, giving a difference of 70 mL for the stroke volume.
During exercise, the cardiac output increases more than the total resistance decreases, so the mean arterial pressure usually increases by a small amount. Pulse pressure, in contrast, markedly increases because of an increase in both stroke volume and the speed at which the stroke volume is ejected.
cardiac output is HR X SV
During exercise, your heart typically beats faster so that more blood gets out to your body. Your heart can also increase its stroke volume by pumping more forcefully or increasing the amount of blood that fills the left ventricle before it pumps.
Jennifer
Pre Capillary Sphincters
Band of contractile mural cells that adjust blood flow into the capillaries. During exercise the sphincters that lead to muscles vasodilate to allow more blood to flow through and get to the working muscles and the ones that lead to organs vasoconstrict.
Arterioles
Small diameter blood vessel that extends and branches out from the artery leads to the precapillary sphincters. During exercise the arterioles that lead to muscles vasodilate to allow more blood to flow through and get to the working muscles and the ones that lead to organs vasoconstrict.
Vasomotor Control Centre
The role of the vasomotor control centre (VCC) is to further aid the performance during exercise by redistributing blood to areas that need it the most (done through vascular shunt mechanisms). The distribution is done by the VCC. The VCC receives information from the chemoreceptors and baroreceptors.
Vascular Shunt Mechanism
Vascular shunt mechanism help blood in the veins get back to the heart. This helps to increase venous return. During exercise more blood is needed to get back to the heart as stroke volume will be increasing. Vascular shunt mechanisms during exercise will increase in effectiveness
Sam
Pocket Valves
Vascular shunt mechanism - one way valve located in the veins which prevent the backflow of blood.
Respiratory Pump
Vascular shunt mechanism - during inspiration and expiration a pressure difference develops between the thoracic and the abdominal cavities which squeezes the blood back to the heart.
Muscular Pump
Vascular shunt mechanism - contraction of skeletal muscles during exercise will compress the veins forcing blood back to the heart
Smooth Muscle
Vascular shunt mechanism - thin muscular lining in the walls of the vein which vasoconstricts to create a VENOMOTOR TONE maintaining pressure in the veins which helps transport blood back to the heart.
Gravity
Vascular shunt mechanism - blood from above the heart returns towards the heart with the help of gravity.
Joe
Heart Rate Regulation Neural and Hormonal control
Neural Control
Sympathetic Nervous System
Sympathetic Nervous System:
The body system must adapt to the environment around it to allow them to perform as efficiently as possible. The sympathetic nervous system responds by stimulating the SA node to increase heart rate.
More Information
The sympathetic nervous system is responsible for
increasing heart rate
. This is controlled by the
CARDIAC CONTROL CENTRE (CCC)
situated in the
MEDULLA OBLONGATA
of the brain.
The CCC receives information from receptors concerning various changes in the body as a result of exercise being undertaken.
The CCC sends down the
ACCELERATOR NERVE
to increase the firing rate of the SA node, this increasing heart rate meaning more oxygen is delivered to the working muscles.
Parasympathetic Nervous System
Parasympathetic Nervous System:
Once exercise has finished and the body begins to recover the parasympathetic nervous system will act to reduce stimulation of the SA node reducing heart rate. This will eventually return to resting levels.
More Information
The parasympathetic nervous system is responsible for
reducing heart rate
. This is also controlled by the
CARDIAC CONTROL CENTRE (CCC)
situated in the
MEDULLA OBLONGATA
of the brain.
The CCC receives information from receptors concerning various changes in the body as a result of exercise ceasing.
The CCC then sends impulses down the
VAGUS NERVE
to decrease the firing rate of the SA node, this decreasing heart rate meaning less oxygen is delivered to the working muscles.
Hormonal Control
In response to exercise the
ADRENALIN
and
NOR-ADRENALIN
are released from the
ADRENAL GLAND.
These hormones have a direct effect on the force of contraction of the heart muscle, this increasing
Stroke Volume
and the firing rate of the SA node, this increasing heart rate.
The combined effect will increase
Cardiac Output
and delivery of oxygenated blood to the working muscles.
Receptors
BARO:
Detects an increase in
pressure.
In the
blood vessels
CHEMO:
Detects an increase in
acidity
or a decrease in
pH
In the
blood
PROPRIO:
Detects
movement
in the
tendons and muscle fibres
Millie- Cardiac Cycle
Cardiac Cycle
Systole
Ventricular Systole
The phase when both ventricles contract to eject blood into the pulmonary artery and aorta for transportation around the circulatory system. Conduction is from the AV node to bundle of his to purkinje fibres
Atrial Systole
The phase when both atria contract to force blood into the ventricles through the bicuspid and tricuspid valve. Conduction is the impulse from the SA node to AV node
Diastole
The relaxing phase of the cardiac cycle. No contraction is taking place and blood will be entering the atriums from the vena cava and pulmonary veins. Heart Filling
Conduction system of the heart linked to the cardiac cycle
Diastole is when there is a relaxation phase of the cardiac cycle, no contraction takes place and blood enters the atriums from the vena cava, after this, the SA node initiates the impulse which is transported through both atria where it is received by the atrioventricular node (AV node). This causes atrial systole, this is when both atria contract to force blood into the ventricles through the bicuspid and tricuspid. The AV node briefly delays the impulse and then it releases it into the bundle of his fibres. Bundle of his splits the impulse into left and right bundle branches where they will reach the purkinje fibres. Once the impulse reaches these fibres both ventricles contract causing ejection of blood into the circulatory system. This is when ventricular systole is the phase when both ventricles contract to eject blood into the pulmonary artery and the aorta for transportation around the body.