Sport Anatomy: Cardiovascular System Flashcards
What does myogenic mean?
The capacity of the heart to generate its own impulses
What is the sinoatrial node (SAN)?
A small mass of cardiac muscle found in the wall of the right atrium that generates the heartbeat. It is more commonly called the pacemaker
What does atrioventricular node (AVN) do?
This node relays the impulse between the upper and lower section of the heart
What does systole mean?
It’s when the heart contract
What is the Bundle of His?
A collection of heart muscle cells that transmit electrical impulses from the AVN via the bundle branches to the ventricles
What are purkinje fibres?
They are muscle fibres that conduct electrical impulses in the walls of the ventricles
The heart muscle is described as being myogenic. What does this mean and discuss how the cardiac conduction system works?
The heart is said to be myogenic because it has the ability to generate its own electrical impulses which originate in the heart muscle itself, with an electrical signal in the SAN. This impulse spreads across the heart like a wave of excitation. This causes atrial systole or the atria to contract. The impulse then passes to the AVN where it is delayed for approximately 0.1 second to fill up with blood. The impulse then travels through the bundle of his which then divides into two branches and then again into the purkinje fibres. This allows the impulse to spread throughout the ventricles causing them to contract. This is known as ventricular systole.
What is the diastole phase?
When the heart relaxes to fill with blood
What is stroke volume?
The volume of blood that leaves the heart during each contraction
What does heart rate mean?
The number of times the heart beats per min
What does the anticipatory rise mean?
The slight increase in heart rate usually before an activity starts due to the expectation of exercise
What does the cardiac output mean?
Is the amount of blood the heart pumps out. Measured in litres per minute (L/min)
What is the formula for cardiac output?
Q=SV x HR
What happens to your resting heart rate after continuous training?
Your resting heart rate decreases
What happens to your muscles after continuous training?
Your muscles become stronger
What happens to your lungs after continuous training?
Your lungs become stronger
What happens to the number of red blood cells after continuous training?
The amount of red blood cells increases
What are the reduced risks of continuous training?
. Reduced risk of cardiovascular disease
. Reduced risk of metabolic syndrome
. May lower risk of some cancers
How does continuous training influence your life span?
It can increases your life expectancy
How does continuous training affect your metabolic rate?
It increases your metabolic rate
What happens to your bones after continuous training?
It improves the bone health
How would the red blood cells differ in a trained v untrained individual?
The trained individual will have more red blood cells delivered to the working muscles whereas the untrained individual have less
How would the heart rate differ for a trained individual compared to a untrained individual?
The heart rate for the trained individual will be lower than the untrained
What does regular training do to heart rate (HR)?
It lowers your resting heart rate, lowers your HR sub-max, slower HR increases, lower HR during exercise, faster return to resting HR
What would the stroke volume in an untrained individual be?
112mL
What would the stroke volume be in a trained individual be?
130mL
What would the stroke volume be for an endurance athlete?
180mL
What happens to the muscles around your heart when you train often and what are the effects of it
The muscles around your heart get bigger. This is known as cardiac hypertrophy. The chambers become larger and more blood will be ejected out of the heart with each beat
What is bradycardia?
A heart rate below 60bpm
During steady state exercise (where the athlete is able to meet the O2 demands with adequate oxygen supply) what happens to your heart rate?
During steady state exercise HR remains the same. With cardiovascular drift your HR will slowly climb
What happens during prolonged steady state exercise (after at least ten minutes in a warm environment)
. Stroke volume and arterial pressure progressively decrease
. A progressive rise in heart rate
Describe cardiovascular drift?
Cardiovascular drift occurs after a period of exercise in a warm environment and this causes the HR to increase which means the stroke volume and arterial pressure decreases. As a result, fluid is lost as sweat so results in a reduced plasma volume and this reduces venous return which causes the cardiac output to increase due to more energy needed to cool body.
What do you do as an athlete to minimise cardiovascular drift?
You should maintain high fluid consumption before and during exercise
Why would a trained footballers A-VO2 increase during a match and why would a trained footballer have a greater A-VO2 difference than an untrained one?
A-VO2 is the difference between the O2 content of the arterial blood arriving at the muscles and the venous blood leaving the muscles. The trained footballers A-VO2 increases because they need more oxygen to be delivered to the working muscles. They need this oxygen to be able to contract the muscles and break down lactic acid. However at rest both trained and untrained footballers A-VO2 will be the same
What is venous return?
It is the return of blood to the right hand side of the heart via the vena cava
What does more blood pumped back to the heart mean? What law does this prove?
It means more blood is pumped out which increases stroke volume. It proves Starling’s law
What is Starling’s law?
When venous return increase there is a greater diastolic filling of the heart. Cardiac muscles are then stretched. This allows for greater force of contraction causing an increased ejection fraction
What are the venous return mechanisms?
. Skeletal muscle pump
. Respiratory pump
. Pocket valves
How does the skeletal muscle aid venous return?
The muscles contract and relax meaning they change shape. This will cause the muscles to press on nearby veins and cause a pumping effect squeezing blood to heart
How does the respiratory pump aid venous return?
The muscles contract and relax during breathing in and out. This causes there to be a pressure change to occur in the thoracic and abdominal cavities. Due to this pressure change it compresses the nearby veins and assist blood return to heart
How do pocket valves aid venous return?
These valves prevent blood flowing back and close once blood has passed through
What other mechanisms of venous return are there?
Gravity because blood from upper body returns to heart
Why is a cool down performed?
Because it keeps the skeletal and respiratory pump working which therefore prevents blood pooling
What happens to the venous return if systolic pressure increases?
If systolic pressure increases then venous return also increases
What happens to venous return if systolic pressure decreases?
If systolic pressure decreases then venous return also decreases
Why does the Bohr Shift shift to the right?
Because when muscles require more oxygen the dissociation of O2 from haemoglobin in the blood capillaries to the muscle tissue occurs more readily and this results in more oxygen being available for use by the working muscles
What are the three factors responsible for the increase in the dissociation of Oxygen from haemoglobin?
. An increase in blood temperature
. An increase in partial pressure of CO2
. pH
How does an increase in blood temperature increase dissociation of oxygen from haemoglobin?
Blood and muscle temp increase during exercise so oxygen will dissociate from haemoglobin more readily
How does an increase in partial pressure of carbon dioxide increase dissociation of oxygen from haemoglobin?
Level of blood carbon dioxide rises during exercise so oxygen dissociates faster from haemoglobin
How does an decrease in blood pH increase dissociation of oxygen from haemoglobin?
More carbon dioxide will lower the pH in the blood. A drop in blood pH will cause oxygen to dissociate from haemoglobin more quickly
What is the sympathetic nervous system?
A part of the autonomic nervous system that speeds up heart rate
What is the parasympathetic nervous system?
A part of the autonomic nervous system that decreases heart rate
What are the cardiac control centres stimulated by?
Chemoreceptors
Baroreceptors
Proprioceptors
What are chemoreceptors?
Tiny structures in the carotid arteries and aortic arch that detect changes in blood acidity caused by an increase or decrease in the concentration of carbon dioxide
What are baroreceptors?
Special senses in tissues in the aortic arch, carotid sinus, heart and pulmonary vessels that respond to changes in blood pressure to either increase or decrease heart rate
What are proprioreceptors?
Sensory nerve endings in the muscles, tendons and joints that detect changes in muscle movement
What is adrenaline?
A stress hormone that is released by the sympathetic nerves and cardiac nerves during exercise, which causes an increase in heart rate
What is ejection fraction?
The percentage of blood pumped up by the left ventricle per beat
What is atherosclerosis?
Occurs when arteries harden and narrow as they become clogged up by fatty deposits
What can cause atherosclerosis?
High blood pressure, high levels of cholesterol, lack of exercise and smoking
What is atheroma?
A fatty deposit found in the inner lining of an artery
What is angina?
Chest pain that occurs when the blood supply through the coronary arteries to the muscles of the heart is restricted
What are the two types of circulation?
Pulmonary and systemic
What is pulmonary circulation?
Deoxygenated blood from the heart to the lungs and oxygenated blood back to the heart
What is systemic circulation?
Oxygenated blood to the body from the heart, and then the return of deoxygenated blood from the body to the heart
What is blood pressure?
It is the force exerted by the blood against the blood vessel wall, and is often referred to as:
blood flow x resistance
What is systolic pressure?
The pressure in the arteries when the ventricles are contracting
What is diastolic pressure?
The pressure in the arteries when the ventricles are relaxing
What are blood pressure and blood flow controlled by?
The vasomotor centre?
How does the vasomotor centre redistribute bloodflow?
Through vasodilation and vasoconstriction
What is vasodilation?
It is when the blood vessel widens to increase blood flow into the capillaries
What is vasoconstriction?
It is when the blood vessel narrows to decrease blood flow
How does vasodilation and vasoconstriction work during exercise?
During exercise, more oxygen is needed at working muscles, so vasodilation will occur in the arterioles supplying these muscles, increasing blood flow, and bringing in the much-needed oxygen, whereas vasoconstriction will occur in the arterioles supplying non-essential organs, such as the intestines and liver
What is the vascular shunt mechanism?
The redirecting of blood flow to the areas where it is most needed
