1.1 Cardiovascular System Flashcards
Diastole
Term used to describe the relaxation phase of the cardiac cycle. Heart ventricles are relaxed and fill with blood
Systole
Term used to describe the contraction phase of the cardiac cycle - the ventricles contract and blood pumped to the arteries
Stroke volume
The volume of blood that leaves the heart during each contraction
Health
State of complete physical, mental and social well-being and not merely the absence of disease and infirmity
Fitness
The ability to meet and cope with the demands of the environment
Physical activity
Being active and taking part in exercise - can directly benefit your physical health and wellbeing
Or doing physical activity to maintain or improve fitness
Heart rate
Number of times the heart beats per minute
Anticipatory rise
Slight increase in heart rate usually before activity starts due to the expectation of exercise
Cardiac output
The amount of blood the heart pumps out. Measured in litres per minute
What is the cardiovascular system made up of
The heart and the blood vessels
Why is an efficient cardiovascular system important during exercise
- deliever oxygen to working muscles
- remove lactic acid
Cardiac muscles - what are they? Where has more?
What does the vena cava do?
Brings deoxygenated blood to the right atrium
What does the pulmonary vein do
Delivered oxygenated blood to the left atrium
What does the pulmonary artery do?
Transports deoxygenated blood from the right ventricle to the lungs to be oxygenated
What does the aorta do
Transports blood from left ventricle to the working muscles
What is the jobs of the valves of the heart
They open and close to allow blood to pass through but also to prevent back flow of blood
Myogenic
The capacity of the heart to generate its own impulses
Sinoatrial node
A small mass of cardiac muscles found in the wall of the right atrium that generates the heart beat. It is more commonly called the pacemaker
Atrioventricular node
This node relays the impulse between the upper and lower sections of the heart
Bundle of his
A collection of heart muscle cells that transmit electrical impulses from the AVN via the bundle branches to the ventricles
Purkyne fibres
Muscle fibres that conduct impulses in the walls of the ventricles
Long term effects on the heart?
- increase in size and strength of the heart
- increase number of capillaries- more efficient oxygen to muscles
- improvement in cardiac output
- decrease resting HR
- Increase in blood volume = more oxygen
Short term effects on the heart?
-increased HR due to adrenaline
-increase in stroke volume
-increase cardiac output
Sympathetic system in bullet points
- increases HR by releasing adrenaline
- adrenaline increases the strength of ventricular contractions = more SV
-Noradrenaline is released aids the spread of electrical impulses = increased HR - increased metabolic activity causes increased lactic acid
-these changes are picked up by chemoreceptors and inform the sympathetic system to flush out waste products - this results in increased cardiac output
Parasympathetic system in bullet points
- releases acetylcholine which spreads electrical impulses which slows the HR down
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.
Baroreceptors
Special sensors 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. Detects decrease in blood pressure
Proprioreceptors
Sensory nerve endings in the muscles, tendons and joints that detect changes in muscle movement.
Chemoreceptors simply
Chemoreceptors → increase in CO2 → increase in heart rate
Baroreceptors simply
Baroreceptors → increase in blood pressure → decrease in heart rate
Proprioreceptors simply
Proprioceptors → increase in muscle movement → increase in heart rate
How to work out cardiac output
SV X HR
Average resting HR
72bpm
Bradycardia?
When RHR is below 60
Pathway of blood through the heart?
Vena cava → right atrium → tricuspid valve → right ventricle → pulmonary valve → pulmonary artery → lungs →pulmonary vein → left atrium → bicuspid valve → left ventricle → aortic semilunar valve → aorta → body
A-vO2 ( arteriovenous oxygen ) difference is ?
Is the difference in the oxygen content between the arterial blood and the Venus blood.
Starlings law?
If more blood is being pumped back into the heart, then more blood has to be pumped out, so stroke volume will increase, this is Starlings’s law
6 venous return mechanisms
- The skeletal muscle pump
- The respiratory pump
- Pocket valves
- Smooth muscle in the walls of the veins
- Gravity
- The suction pump action of the heart
The skeletal muscle pump
When muscles contract and relax, they change shape. This change in shape means muscles press on nearby veins which squeezes blood towards the heart.
The respiratory pump
When muscles contract and relax during breathing in and out, pressure changes occur in the chest and the stomach, changing pressure compress nearby veins and assist blood back to the heart
Pocket valves
The presence of valves and shows that blood only flows in one direction, this is because once the blood has passed through the vowels they close to prevent backflow of blood
Smooth muscle in the walls of the veins
Helps squeeze blood back to the heart
Gravity
Helps blood return to the heart from upper body
During exercise the curve shift to the right this is called the Bohr shift. What causes this ?
Caused by increase in blood pressure co2 levels increase , body temperature and blood acidity during exercise. This allows oxygen to Dissociate from haemoglobin.
Explain how redistribution blood occurs during exercise
Redistribution of blood flow is different during exercise compared to rest. During exercise the skeletal muscles require more oxygen so more blood needs to be redirected to them in order to oxygen demands. Redirecting of blood flow is known as vascular shunting. The vasomotor center in the medulla oblongata causes vasoconstruction of the arterioles in the working muscles.
Myoglobin
- stores oxygen in the muscles
- has a higher affinity for oxygen
Blood pressure
Is the force exerted by blood vessel wall
Explain the cardiovascular drift?
During exercise at steady state ( min 10 mins ) and in a hot environment, your body you will lose fluid in the plasma because you sweat. This will result in a gradual decrease in stroke volume and a gradual increase in heart rate. Resolving a slight increase in cardiac and reduced Venous return.
Haemoglobin
-Transports oxygen in the blood
- Muscles receive more oxygen
-increase in oxygen release
