Cardiovascular System - Applied Anatomy and Physiology (Paper 1) Flashcards
what is the definition of health
A state of complete physical, mental and social well-being and not merely the absence of disease and infirmity/injury.
what is the definition of fitness
The ability to meet and cope with the demands of the environment
what is the definition of physical activity
Being active and taking part in exercise
what is the definition of heart rate
The number of times the heart beats per minute
what is the definition for Anticipatory Rise
Slight increase in heart rate usually before activity starts due to the expectation of exercise
what is the definition of stroke volume SV
The volume of blood that leaves the heart during each contraction
what is the definition, unit and equation of cardiac output
-The amount of blood the heart pumps out per minute
-Measured in litres per minute (L/min)
- cardiac output = Stroke Volume x Heart Rate
what is the definition of systole
the contraction phase of the cardiac cycle - the ventricles contract and pump blood to the arteries
(Right Ventricle to the pulmonary artery and lungs, Left Ventricle to the aorta and the body)
what is the definition of diastole
Term used to describe the relaxation phase of the cardiac cycle. The heart ventricles are relaxed and fill with blood
what vein carries blood back to the heart
superior vena cava (delivers deoxygenated blood from any part above the heart)
inferior vena cava (delivers deoxygenated blood from any part below the heart)
what chamber in the heart does the both vena cava’s empty into
right atrium
what artery takes blood to the rest of the body
aorta
what prevents the backflow of blood
valves
what are the three valves in the heart
tricuspid valve
bicuspid valve
semilunar valves
what is the sheet of cardiac muscle between both ventricles called
inter-ventricular septum
why does the left side of the heart have more cardiac muscle than the right
the left side holds oxygenated blood, this blood needs to be pumped to the rest of the body. the larger muscle size allows the heart to generate enough force necessary to pump the blood to the whole body
what is the pathway of blood
- Venae Cavae (Superior and Inferior)
- Right Atrium
- Tricuspid Valve
- Right Ventricle
- Pulmonary semilunar valve
- Pulmonary artery
- LUNGS to drop off CO2 and pick up O2
- Pulmonary Veins
- Left Atrium
- Bicuspid valve
- Left ventricle
- Aortic semilunar valve
- Aorta
- BODY
what would the difference be between an a trained person and untrained persons resting heart rate
Trained Individuals Resting HR’s are much lower than untrained individuals
why is a trained person resting heart rate lower than untrained person
cardiac hypertrophy -> heart is bigger -> pumps more blood -> larger SV ->
increased size of chambers -> bigger SV -> heart doesn’t have to beat as many times
what is the heart conduction system
the system that allows the heart to produce a heart beat
why is the heart myogenic
because it has the ability to make its own electrical impulse
what is the first stage of the heart conduction system
the sinoatrial node will send an electrical impulse throughout the atria
what happens in the second stage of the heart conduction system
the impulse spreads across the atria, this will cause the atria to contract
what happens in the third stage of the heart conduction system
the impulse passes through the atrioventricular node where it is delayed for 0.1s to allow the atria to fully contract before the ventricles contract - this gives the ventricles time to fill with blood
what happens in the fourth stage of the heart conduction system
the impulse then travels through the bundle of his which then divides into two branches and then again into purkinje fibres
what happens in the fifth and final stage of the heart conduction system
this allows the impulse to spread throughout the ventricles causing them to contract - also known as ventricular systole
What are the three main mechanisms that can control the impulses from the SAN
Sympathetic nervous system
Parasympathetic nervous system
Medulla Oblongata
What is the sympathetic system
A part of the autonomic nervous system that speeds heart rate
What is the Parasympathetic System
A part of the autonomic nervous system that decreases heart rate
What is the medulla oblongata
The most important part of the brain as it regulates processes that keep us alive such as breathing and heart rate
What is the ANS
Autonomic nervous system
What does the ANS do
Determines the rate at which the SAN sends out impulses
How does the sympathetic nervous system increase HR
It releases adrenaline
What does adrenaline increase in the sympathetic nervous system
It increases the strength of ventricular contraction which then increases stroke volume
In the sympathetic nervous system what does noradrenaline do
Aids the spread of electrical impulse throughout the heart, increasing HR
In the sympathetic nervous system what does an increased metabolic rate cause
Increased CO2 and lactic acid, decrease in blood PH (more acidic)
How are the changes of an increased metabolic rate picked up
By the chemoreceptors and they inform the sympathetic system to increase HR to flush out the waste products. This results in an increased cardiac output
What is the parasympathetic nervous system
The nervous system that slows the speed of the heart down which decreases HR
What does the parasympathetic nervous system do to lower the heart rate
Releases Acetylocholine which slows the spread of impulses throughout the heart, this results in a lower heart rate
What are receptors
Part of the nervous system that detects changes in the body.
What do chemoreceptors do
- Detect changes in CO2
- an increased concentration of CO2 in the blood will stimulate the sympathetic nervous system
- which means the heart will beat faster
What do baroreceptors do
- Baroreceptors respond to the stretching of the arterial wall caused by changes in blood pressure
- baroreceptors establish set points for blood pressure
- an increase or decrease above or below this set point results in the baroreceptors sending signals to the medulla oblongata
What do proprioceptors do
Increases HR when muscle movement increases
What is adrenaline
- A stress hormone that is released by the sympathetic nerves and cardiac nerve during exercise which causes an increase in heart rate
- it stimulates the the SAN leading to an increase in the speed of force of contraction and therefore increased cardiac output
What is ejection fraction
The percentage of blood pumped out by the left ventricle per beat
What are the proprioceptors
Sensory nerve endings in the muscles, tendons and joints that detect changes in muscle movement
Proprioceptors -> detect increase in muscle movement - > increase in HR
What are 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
Baroreceptors - > detected increased blood pressure -> decreases HR
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
Chemoreceptors - > increase in CO2 -> increase in HR
What is stroke volume
The amount of blood pumped out by the ventricles in each contraction
What is the diastole phase
When the heart relaxes to fill with blood
What does stroke volume depend on
- Venous return
- the elasticity of cardiac fibres
- contractility of cardiac tissue
How does venous return affect stroke volume
If the venous return increases then stroke volume will increase
What is venous return
The volume of blood return to the heart via veins
How does the elasticity of cardiac fibres affect stroke volume
The more the cardiac fibres can stretch, the greater the force of contraction (which also increases ejection fraction - starlings law)
What is starlings law
Increased venous return -> greater diastolic filling of the heart -> cardiac muscle stretched -> more force of contraction -> increased ejection fraction
What is cardiac output
The volume of blood pumped out by the hearts ventricles per minute
How does the contractility of cardiac tissue affect stroke volume
The greater the contractility of cardiac tissue, the greater the force of contraction
How do you calculate cardiac output
Cardiac Output (Q) = Stroke volume (SV) x Heart Rate (HR)
What is cardiac hypertrophy
The thickening of the muscular wall of the heart so it becomes bigger and stronger
What is bradycardia
A decrease in resting heart rate to below 60 beats per minute
How does having a bigger heart affect cardiac output
Enables more blood to be pumped out and as a result the blood doesn’t need to pump as often so resting HR decreases
How do u calculate maximum heart rate
220 - your age
What is atherosclerosis
Occurs when arteries harden and narrow as they become clogged up by fatty deposits
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 happens if a piece of fatty deposit (atheroma) breaks off in the coronary artery
can cause blood clot, cuts off supply of oxygen to the heart resulting in a heart attack
What is blood pressure
The force exerted by the blood against the blood vessel wall
What is a stroke
When blood supply to the brain is cut off
What is steady state
Where the athlete is able to meet the oxygen demand with the oxygen supply
How does exercise affect cholesterol levels
Regular activity lowers bad LDL cholesterol and increases good HDL cholesterol levels
What are the two types of strokes
- Ischaemic, occurs due to blood clot
- Haemorrhagic, occurs when a weakened blood vessel supplying the brain bursts
what is cardiovascular drift
Cardiovascular drift occurs after a period of exercise -> HR increase -> stroke volume decreases -> because fluid is lost as sweat -> resulting in a reduced plasma volume -> reduced venous return -> cardiac output increases (no energy needed to cool the body)
What is the vascular system made of
Blood vessels that carry blood through the body
What are the two types of circulation
- pulmonary, deoxygenated blood from hearts to lungs and oxygenated blood back to the heart
- systemic, oxygenated blood to the body and return of deoxygenated blood back to the heart
What are the five different blood vessels
- Artery
- Arterioles
- Capillaries
- Venules
- Veins
What is the structure of veins
- Thinner muscle/elastic tissues
- valves
- wider lumen
What is the structure of arteries
- more elastic tissue in wall
- smaller lumen
What is the structure of capillaries
wide enough for once RBC to pass through (allows exchange of nutrients with the tissues by diffusion)
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 is venous return
Return of blood to the right side of the heart via the vena cava
What mechanisms help venous return
- Skeletal muscle pump
- respiratory pump
- pocket valves
- gravity
What is the skeletal muscle pump
When the muscles contract and relax they change shape, means that the muscles press on nearby veins causing a pumping effect and squeeze blood towards the heart
What is the respiratory pump
Respiratory muscles causes pressure changes in the thoracic and abdominal cavities. The changes in pressure compress nearby veins and assist blood return to the heart
What are pocket valves
Valves that make sure that blood only flows in one direction. Once the blood passes through the valve it closes.
What could stimulate an increase in venous return
- increase in venous pressure
- decrease in right atrial pressure
- decrease in venous resistance
What could stimulate a decrease in venous return
Increasing right atrial pressure
What is venous return determined by
Pressure gradient
What is the venous return pressure gradient
Venous pressure (PV) - Right atrial pressure (PRA)
——————————————————————
Venous vascular resistance (RV)
Why is the pressure in the right atrium and veins low
- So the pressure gradient driving venous return is also relatively low.
- Small changes can cause large changes in pressure in either right atrium or veins (affects venous return)
What is plasma
The fluid part of blood that surrounds blood cells and transports them
What is haemoglobin (Hb)
An iron containing pigment found in red blood cells which combines with oxygen to form oxyhemoglobin
What is myoglobin
An iron containing pigment in slow twitch muscle fibres which has a higher affinity for oxygen than Hb. It stores oxygen in the muscle fibres which can be used quickly when exercise begins
What is mitochondria
Referred to as the powerhouse of the cell as respiration and energy production occur there
When will haemoglobin carry four oxygen molecules
When the partial pressure of oxygen is high in the blood
Why does the oxygen dissociate from oxyhaemglobin at the muscles/respiring tissues
Because there is a low partial pressure of oxygen there
In muscles oxygen is stored by….
Myoglobin. Has a higher affinity for oxygen and stores oxygen for mitochondria until it is used by the muscles
What is the Bohr shift
When an increase in blood carbon dioxide and a decrease in pH results in a reduction of the affinity of haemoglobin for oxygen
What is pH
A measure of acidity. Range goes from 1 to 14. Anything less than 7 indicates acidity
Why does the Bohr shift occur
The s shaped curve shifts to the right because when muscles require more oxygen, the dissociation of oxygen from haemoglobin in the blood capillaries to the muscle tissue occurs more readily
What three factors are responsible for the Bohr shift
- increase in blood pressure
- partial pressure of CO 2
- pH
How does increasing blood temperature affect the Bohr shift
when blood and muscle temperature increases during exercise, oxygen will dissociate from haemoglobin more readily
How does a increasing partial pressure affect the Bohr shift
As the level of blood CO2 rises during exercise, oxygen will dissociate faster from haemoglobin
How does pH affect the Bohr shift
More CO2 will lower pH in the blood, a drop in pH will cause oxygen to dissociate from haemoglobin more quickly
How does the distribution of blood flow differ at rest compared to exercise
The skeletal muscle require more oxygen while exercising so the body redirect blood in order to meet the oxygen demand (vascular shunting)
Why would a full gut have a detrimental affect performance
- blood gets directed to the working muscles instead of gut
- blood flow also has to remain constant to brain, heart (to beat faster) and skin (to cool us down)
- detrimental on performance as less oxygen is being made available
What is vasodilation
The widening of the blood vessels to increase the flow of blood into the capillaries
What is vasoconstriction
The narrowing of the blood vessels to reduce the blood flow into the capillaries
Why is redistribution of blood important
- increases supply of oxygen to working muscles
- removal of waste products (CO2, lactic acid)
- ensure blood goes to skin to regulate body temprature
- more blood to the heart as it is a muscle and requires extra oxygen during exercise
What is Arterio-venous difference
The difference between the oxygen content of the arterial blood arriving at the muscles and the venous blood leaving muscle
What is the level of Arterio-venous difference at rest and exercise
- At Rest: Low, as not much oxygen is required by the muscles
- At Exercise: High, much more oxygen required by the muscles
How is gaseous exchange affected by an increase in Arterioles-venous difference
An increase affects gaseous exchange at the alveoli so more oxygen is taken in and more CO2 is removed.
How is Arterio-venous difference improved
Through training
How is oxygen transported
- During exercise, when oxygen diffuses into the capillaries supplying the skeletal muscles, 3% dissolves into the plasma and 97% combines with haemoglobin
- when fully saturated haemoglobin will carry 4 oxygen molecules
- at the tissues, oxygen disassociates from oxyhemoglobin due to the lower pressure of oxygen that exists there
- in the muscles oxygen is stored by myoglobin which has a higher affinity for oxygen and will store the oxygen for the mitochondria until it is used by the muscles
How does the A-Vo2 diff vary amongst trained and untrained individuals
regular aerobic exercise leads to adaptations like higher SV, cardiac output, capillarisation of muscles etc. These adaptation improve oxygen delivery and extraction to and from the tissues. So the trained individuals have a higher A-VO2 diff than the untrained individual both at rest and exercise as the untrained individual may not be adapted to the demands of exercise resulting in a lower oxygen carrying capacity.
