1.1 The Cardiovascular System Flashcards
Myogenic
The capacity of the heart to generate its own impulses
SAN
Cardiac muscle found in the wall of the right atrium that generates the heartbeat.
AVN
The atrioventricular node relays the impulse between the upper and lower sections of the heart but will delay it 0.1 seconds to allow the ventricles to fill up
Systole
When the heart contracts
Diastole
When the heart relaxes
Bundle of His
A collection of heart muscle cells that transmit electrical impulses from the AVN via the bundle branches to the ventricles
Purkinje fibres
Muscles fibres that conduct impulses in the walls of the ventricles causing them to contract
Adrenaline
A stress hormone that is released by the sympathetic nerves and cardiac nerve during exercise causing an increase in heart rate.
Stroke volume
The volume of blood pumped by the heart ventricles in each contraction
Ejection fraction
The percentage of blood pumped out by the left ventricle per beat
Cardiac output + equation
The volume of blood pumped out by the ventricles per minute.CO=SVxHR
Cardiac hypertrophy
The thickening of the muscular wall of the heart so it becomes bigger and stronger
Bradycardia
A decrease in resting heart rate to below 60 bpm
Sympathetic system
A part of the autonomic nervous system that speeds up heart rate
Parasympathetic system
A part of the autonomic system that decreases heart rate
Medulla Oblongata
The most important part of the brain as it regulates processes that keep us alive such as breathing and heart rate
What does the neural control system involve and what do each of them detect?
𝐁𝐚𝐫𝐨𝐫𝐞𝐜𝐩𝐞𝐭𝐨𝐫𝐬:
Detect changes in blood pressure.
𝐏𝐫𝐨𝐩𝐫𝐢𝐨𝐜𝐞𝐩𝐭𝐨𝐫𝐬:
Detect movement and stretch in muscles.
𝐂𝐡𝐞𝐦𝐨𝐫𝐞𝐜𝐞𝐩𝐭𝐨𝐫𝐬:
Detect changes in carbon dioxide
Chemoreceptors
detect changes in blood acidity caused by an increase or decrease in the concentration of carbon dioxide. Increase in CO2 increase heart rate.
Baroreceptors
Special sensors in tissues in the aortic arch, carotid sinus, heart and pulmonary vessels that respond to changes in blood pressure. Increase blood pressure decrease in heart rate.
Proprioceptors
Sensory nerve endings in the muscles, tendons and joints that detect changes in muscle movement. Increase in muscle movement increase in heart rate.
Plasma
The fluid part of the body that surrounds blood cells and transports them
Haemoglobin
An iron-containing pigment found in red blood cells, which combines with oxygen to form oxyhaemoglobin.
Myoglobin
It stores the oxygen in the muscle fibres which can be used quickly when exercise begins
Mitochondria
Site of respiration and energy production
Bohr shift
When an increase in blood carbon dioxide and body temperature and decrease in pH results in a reduction of the affinity of haemoglobin for oxygen
pH
A measure of acidity. Anything less than 7 indicates acidity
Oxyhaemoglobin dissociation curve
During exercise the dissociation curve will shift to the right - this is the Bohr effect. This is caused by an increase in both blood co2 and body temperature and a decrease in ph allowing more oxyhaemoglobin to dissociate into the muscles
Vascular shunting
The redistribution of cardiac output
Vasoconstriction
The narrowing of the blood vessels to reduce blood flow into the capillaries
Vasodilation
The widening of the blood vessels to increase the flow of blood into the capillaries
Blood pressure
The force exerted by the blood vessel wall
Systolic pressure
The pressure in the arteries when the ventricles are contracting
Diastolic pressure
The pressure in the arteries wen the ventricles are relaxing
Venous return
The return of blood to the right side of the heart
Starlings Law
The greater venous return, the greater stroke volume
The 6 venous return mechanisms
The skeletal muscle pump
the respiratory pump
pocket valves
gravity
smooth muscle
the suction pump action of the heart
The skeletal muscle pump
When muscles contract and relax they change shape. This change in shape meas that muscles press on the nearby veins and cause a pumping effect and squeeze the blood towards the heart
The respiratory pump
When respiratory muscles contract causing pressure changes in the thoracic and abdominal cavities. This change in pressure compresses the nearby veins and assist blood to the heart
Pocket valves
Prevent the back flow of blood
Smooth muscle
Thin layers inside the walls of veins which helps to squeeze blood back to the heart
Gravity
Helps the blood to return to the heart from the upper body
Steady state
Where the athlete is able to meet the oxygen demand with the oxygen supply
A stroke
Occurs when the blood supply to the brain is cut off
Cardiovascular drift
It occurs after 10 minutes of exercise in a warm environment.
At this point, heart rate increases gradually, stroke volume decreases.
Fluid is lost as sweat resulting in a reduced plasma and reduced venous return.
Cardiac output also increases due to more energy needed to cool down the body.
Atrio-venous drift (A-VO2 diff)
The difference between the oxygen content of the arterial blood arriving at the muscles and the venous blood leaving the muscles.
Atherosclerosis
Occurs when arteries harden and narrow as they become clogged up by fatty deposits
Atheroma
Fatty deposits found in the inner lining of an artery
Angina
Chest pain that occurs when the blood supply is restricted
LDL’s
Low density lipoproteins.
Transport cholesterol in the blood to the tissues.
Classed as ‘bad’ cholesterol as it is linked to an increased risk of heart disease.
HDL’s
High density lipoproteins.
Transport excess cholesterol in the blood back to the liver where it is broken down (and disposed of).
Classed as ‘good’ cholesterol as it lowers the risk of heart disease.
How can cholesterol levels be improved?
aerobic activities
low-fat diet
regular exercise
What are the 4 causes of deteriorating coronary blood vessels?
Smoking
Alcohol
Sedentary lifestyle
A high-fat diet
What is the diastole phase of the cardiac cycle?
The heart at this point is relaxing and atria are filling up with blood
What is the systole phase of the cardiac cycle?
2 Phases
Pressure has built up in the atria during diastole phase
𝐀𝐭𝐫𝐢𝐚𝐥 𝐬𝐲𝐬𝐭𝐨𝐥𝐞 𝐩𝐡𝐚𝐬𝐞:
1. Valves are now forced open and remaining blood is forced into ventricles.
𝐕𝐞𝐧𝐭𝐫𝐢𝐜𝐮𝐥𝐚𝐫 𝐬𝐲𝐬𝐭𝐨𝐥𝐞 𝐩𝐡𝐚𝐬𝐞:
2. Ventricles now contract increasing the pressure within these chambers.
3. Aortic valve and pulmonary valve are forced open, allowing blood to be pushed through into the aorta or pulmonary artery.
The cardiac conduction system
SAN (the pacemaker) generates an electrical impulse (atrial systole) which travels to the AVN which delays the impulse by 0.1 sec allowing for the chambers to fill with blood. The impulse is relayed onto the Bundle of His which then separate into the purkinje fibres which causes ventricular systole so the ventricles to contract
