1.1 Cardiovascular system (add more detail) Flashcards
What does the Cardiac conduction system refer to?
How the heart contracts/how the heart creates its own heart beat
List the CCS in order of impulse travel
SA node (sinoatrial node)
AV node (atrioventricular node)
Bundle of HIS
Purkinje fibers
Explain the function of the SA node?
Sinoartial node
- Sends electrical impulses to spread throughout both atria to stimulate atrial systole.
- Initiates all heart beat and detriments heart rate.
- Natural pace maker of the heart.
Explain the function of the AV node?
Atrioventricular node
- Delays the cardiac impulse, from SA node, to ensures the atria have ejected all the blood into the ventricles before ventricles contacts.
- The AV node receives signals from the SA node and passes them onto the Bundle of HIS.
Explain the function of the Bundle of HIS?
The Bundle is divided into left and right bundle branches and into purkinje fibres
-Conduct the impulses to the apex of the heart. The signals are then passed to Purkinje fibers
Explain the function of the Purkinjie fibers?
- Purkinjie fibres spreads signal throughout the ventricular myocardium causing Ventricular systole
Identify and explain the order in which a cardiac impulse travels?
- SA node initiates heart beat and spreads impulse across top two chambers (atria) creating atrial systole.
- AV node delays impulse (0.1sec) from SA node to ensure atria have ejected all blood into ventricles and sends impulse to Bundle of HIS.
- Conducts impulse to the apex of the heart and then sent to Purkinjie fibers.
- Purkinjie fibers cause ventricular systole
Key terms brain dump
Conducts Electrical impulses Systole Diastole Eject CCS Myogenic Symp
What is the term used when the heart is contracting and relaxing
Systole and diastole
Name all the chambers of the heart
Artia (left and right
Ventricles (left and right)
Ventricle (left+right)
What is the first things that happens during a heart beat?
SA node sends impulse across both atriums causing ATRIAL SYSTOLE
How does the heart control the rate at which it beats
SA node sends impulse to create atrial systole. Impulse reaches AV node which delays cardiac impulse to ensure all blood has been ejected out the atria and into the ventricles. Impulse then sent down to Bundle of HIS and conducts into Purkinje fibres. This will achieve ventricular systole.
How do you measure the electrical activity and rhythm of the heart?
ECG: Electrocardiogram
Why is one side of the heart’s walls bigger than the other?
The ventricles of the heart have thicker muscular walls than the atria. This is because blood is pumped out of the heart at greater force from these chambers compared to the atria. Therefore need to withstand higher pressure.
Which chamber in the heart are larger and explain why?
The left ventricle is the biggest chamber as it has to pump blood to the rest of the body (further distance) whereas the right ventricle only pumps to the lungs.
Name the main blood vessels that enter and leave the heart
Aorta, vena cava and pulmonary artery = AWAY
Pulmonary vein = TOWARDS
Which blood vessel brings deoxygenated blood back to the heart?
Vena cava brings deoxygenated blood to right atrium
Which blood vessel delivers oxygenated blood to the heart?
The Pulmonary vein delivers oxygenated blood to the left atrium.
Whats the difference between arteries and veins?
Arteries carry blood AwAy from the heart, and veins carry blood towards the heart.
What is the function of the Aorta?
Leaves the left ventricle with oxygenated blood to the rest of the body
What is the function of the pulmonary artery?
Leaves the right ventricle with deoxygenated blood to the lungs
The heart acts as a _______ forcing blood around the body
The heart acts as a DOUBLE PUMP forcing blood around the body
Name the hearts two circuits
Pulmonary circulation
Systemic circulation
Systemic circulation
Explain the difference between the hearts circulatory systems
Pulmonary circulation: Deoxygenated blood from the heart to the lungs and oxygenated blood back to the heart
Systemic circulation: Oxygenated blood to the body from the heart and deoxygenated blood from body back to heart.
“The cardiac muscle cells in the heart are myogenic” what is meant by this?
Heart muscle is described as being myogenic as the beat starts in the heart muscle itself with an electrical signal in the sinoatrial node (SAN).
CCS ensures that ………. increases during exercise to allow the …….
CCS ensures that ..heart rate.. increases during exercise to allow the working muscles to receive more oxygen.
Explain the functions of the Neural Control Mechanism?
Involves the sympathetic nervous system = stimulates the heart beat faster. Parasympathetic system which returns the heart to its resting level. Both are coordinated by the Medulla of the brain which is the cardiac control centre.
Sympathetic nerve impulses are sent to the SA node and there is an increase in HR.
Parasympathetic nerve impulses so that the heart rate decreases.
What is the Cardiac control center stimulated by?
The cardiac control center is stimulated by chemoreceptors, baroreceptors and proprioceptors and will send impulses through either the sympathetic system to increase HR, or the parasympathetic to decrease HR.
What are the mechanisms which affect the rate at which cardiac impulses are fired?
Neural Control mechanisms:
Chemoreceptors
Baroreceptors
Proprioceptors
Explain the role of chemoreceptors?
Sense chemical changes such as CO2
Describe why chemoreceptors are important during exercise?
During exercise, chemoreceptors detect an increase in CO2. An increase concentration of CO2 in the blood will stimulate the sympathetic nervous system which means the heart will beat faster.
Explain the role of Baroreceptors?
Baroreceptors detect changes in Blood Pressure.
Detect the stretch in the arterial wall caused by changes in blood pressure. Baroreceptors have a set point for blood pressure.
Describe the function of Baroreceptors
An increase/decrease in set BP causes baroreceptors to send signals to the medulla to either increase or decrease heart rate.
Increase in arterial pressure -> increase stretch of the arterial wall -> increase stretch of baroreceptor sensors = decrease heart rate
Decrease In arterial pressure -> decrease stretch of arterial wall -> decrease stretch of baroreceptor sensors = increase heart rate
Why is it important for Baroreceptors to increase heart rate during exercise?
At the start of exercise the baroreceptors set point increases which is important as the body does not want heart rate to slow down as this would negatively affect performance = less oxygen would be delivered to the working muscles.
What are Proprioceptors?
Sensory nerve endings in muscles, tendons and joints that provide info about movement and body position.
Why are Proprioceptors important during exercise?
At the start of exercise they detect increase muscle movements.
These receptors send impulses to the medulla which sends an impulse through the sympathetic nervous system to the SA node to increase hr.
Explain the hormonal control mechanism
The release of the hormone Adrenaline in the blood during exercise is known as hormonal control. Released into the blood and causes the heart to beat faster (fight or flight response). Occurs within 2-3 min of stressful situations. Released by the sympathetic NS which stimulates the SAN resulting in an increase speed and force of contraction = increase cardiac output. Results in more blood being pumped to the working muscles for oxygen replenishment.
What is stroke volume?
The volume of blood pumped out of the heart’s ventricles each contraction
Memory tool: strOke = not enough blood OUT to the brain = vol of blood pumped OUT each contraction
What does stroke volume depend on?
- Elasticity of Cardiac muscles (more the heart can stretch the greater force of contraction)
- Venous return
What is cardiac output?
The volume of blood pumped out the heart ventricles per minute.
Memory tool: oUtpuT = minUT
How is someones maximum HR calculated?
220 - age = MAX HR
What is meant by ‘Ejection fraction’?
% of blood pumped out the left ventricle per beat
What is Venous return?
The volume of blood RETURNing to the right ventricle of the heart
Stroke volume increases as ___ increases
Stroke volume increases as exercise intensity increases
What is meant by Heart Rate?
the number of times the heart beats per minute
How does HR respond to exercise?
Heart rate increases with exercise. HR will increase in direct proportion to exercise intensity.
On a Heart rate diagram, why is there a slight increase in HR before exercise has officially started?
This is called the anticipatory rise due to the hormone adrenaline = SAN increase HR
What words should be used when describing a heart rate diagram?
Anticipatory rise
Sharp rise
Steady state
Rapid decline
Return to resting level
Maximal & Submaximal
PLATEAU (even out)
What is meant by cardiac hypertrophy?
when the heart muscle grows becoming stronger and bigger due to thickening of muscular walls
What is the formula for calculating cardiac output?
stroke vol x HR = … ml
What is meant by Bradycardia?
decrease in resting HR below 60bpm
How does cardiac output change in response to exercise?
During exercise there is a large increase in cardiac output due to an increase in HR and stroke volume.
Define the terms ‘cardiac output’ and ‘stroke volume’ and explain the relationship between them.
Cardiac output: The volume of blood pumped out the heart ventricles per minute
Stroke Volume: The volume of blood pumped out of the heart’s ventricles each contraction
As cardiac output increases so does stroke volume.
Explain Coronary heart disease?
Occurs when the coronary artery (supplying the heart with oxygenated blood) narrows due to gradual build up of ARTHEROMA (fatty deposits/plaque). This is called Atherosclerosis = narrowing of artery.
What is meant by HIGH blood pressure?
Force exerted by the blood against the blood vessel wall. High blood pressure put extra strain on the arteries and could lead to heart attack.
What effect does regular exercise have on blood pressure?
Regular exercise can reduce systolic and diastolic blood pressure reducing risk of heart attack.
Explain everything there is to know about cholesterol
Made in the liver, carried in the blood . There are two types:
Low density lipoproteins LDL : transport cholesterol in the blood to the tissue classed as ‘bad’ cholesterol as they increase risk of heart disease.
High density lipoproteins HDL : transport excess cholesterol in the blood back to the liver where its broken down. Classed as ‘good’ cholesterol as they lower the risk of getting heart disease.
How does the heart rate respond to exercise?
Medulla sends impulse down sympathetic nervous system. SA node is stimulated to increase HR once exercise starts.
Memory tool:
CO2 = CHemical = Chemoreceptors
Blood pressure = Baroreceptor
muscle/Physical movement = Proprioceptors
Memory tool:
CO2 = CHemical = Chemoreceptors
BP = Blood Pressure = BarorecePtor
muscle/Physical movement = Proprioceptors
What is responsible for regulating cardiac function?
Medulla oblongata in the brain
How does exercise affect HR?
Exercise causes for an increase in CO2 levels detected by the chemoreceptors, increase in blood pressure detected by baroreceptors and increase in muscular movement detected by proprioceptors. These receptors are going to send this info to the Medulla and come to the conclusion that due to all the various increases, the body must be exercising. Sends impulse down sympathetic nervous system, to the SA node and HR increases.
Memory tool: parasympathetic = parachute = slows down
Memory tool: parasympathetic = parachute = slows down
Identify where the receptors are located within the body?
Chemoreceptors: carotid artery
Baroreceptors: carotid artery
Proprioceptors: muscles, tendons and joints
Explain what causes a stroke to occur?
When the blood supply to the brain is cut off causing damage to brain cells.
Explain what and why cardiovascular drift occurs
A PROGRESSIVE decrease in stroke volume and arterial blood pressure, with a progressive rise in heart rate. Occurs during prolonged exercise despite the intensity of exercise remaining the same.
Intensity of exercise may stay constant however, HR will progressively increase and stroke volume decrease.
Describe the function and structure/characteristics of a vein
Veins transport deoxygenated blood back to the heart (pulmonary vein is an exception). Thin walls, blood is at low pressure, contain valves and wide lumen.
Describe the function and structure/characteristics of an Artery
Transport oxygenated blood around the body (exception of pulmonary artery). Has the highest pressure, thick walls and small lumen.
Describe the function and structure/characteristics of a capillary network
Wide enough to only allow a single RBC to pass through at a time. This slows down blood flow and allows for diffusion.
What is meant by the term diffusion?
Diffusion is the movement of gas (oxygen) from an area of high concentration to an area of low concentration.
What is meant by the term Blood pressure?
Force exerted by the blood against the blood vessels wall
What are some mechanism that help venous return?
Valves
Gravity
Thin smooth muscle within veins
Skeletal muscle pump
What is the function of the Mitochondria?
‘powerhouse’ of the cell because respiration and energy production occur there.
What is myoglobin?
Stores oxygen in the muscle fibre to be used quickly when exercise begins.
What is Oxyhaemoglobin?
Haemoglobin carrying oxygen
What is meant by Vascular shunting?
Redistribution of blood flow during exercise e.g. more blood directed to working muscles than gut
Explain Bohr shift
When an increase in blood carbon dioxide and a decrease in blood pH results in a reduction of the affinity of haemoglobin
Whats the difference between Vasoconstriction and Vasodilation
Vasoconstriction: narrowing of the blood vessels to reduce blood flow into the capillaries
Vasodilation: widening of the blood vessels to increase blood flow to capillaries
What is the function of Haemoglobin?
Carrys oxygen
Explain starlings law
A greater force of contraction can increase the ejection fraction. The greater venous return, the greater stroke volume
State the key term being described: the beat starts in the heart muscle itself.
myogenic - the heart is described as myogenic
List the receptors involved in the Neural control mechanism
Chemoreceptors (CHemical Co2)
Baroreceptors (BP)
Proprioceptors (Physical movement)
State the function of the Vena Cava
brings deoxygenated blood to the right atrium
State the function of the Pulmonary vein
delivers oxygenated blood to the left atrium
State the valves and where they are located within the heart
- Tricuspid = between right atrium & ventricle
- Pulmonary Semilunar = pulmonary artery
- Bicuspid = left atrium & ventricle
- Aortic Semilunar = Aorta
What part of the brain regulates breathing and heart rate?
Medulla oblongata
Memory tool:
PARAsympathetic = PARAlympics = slow = slows heart rate back to resting level
Memory tool:
PARAsympathetic = PARAlympics = slow = slows heart rate back to resting level
Explain the difference between the parasympathetic and sympathetic nervous systems
Parasympathetic returns heart rate to resting level.
Sympathetic stimulates the heart to beat faster.
The the functions of the neural control mechanisms during exercise
Sympathetic nervous system sends impulses to the SAN and there is a decrease in parasympathetic nerve impulses so the heart rate increases.
Explain what makes up the nervous system?
Central nervous system (brain and spinal cord) and the peripheral nervous system (nerve cells that transmit information to and from CNS)
Explain the diastole phase of the heart
When the heart muscle relaxes to fill with blood
Explain the term ‘Atheroma’
fatty plaque/deposit found in the artery
Explain the term ‘Angina’
Chest pain that occurs when blood supply through the coronary arteries to the muscles of the heart is restricted
During which state is Blood pressure lower - systolic or diastolic
diastolic as the ventricles are relaxing
Explain the Venous return mechanisms
Skeletal muscle pump - The change in shape (contracting) of the muscles causes blood to be pumped towards the heart
Respiratory pump - thoracic and abdominal cavity muscles contract while breathing in and out. The pressure caused by the compression causes nearby veins to assist in pumping blood back to the heart.
Pocket valves - valves ensure that blood flows in one direction and prevent back flow.
Gravity - helps blood return to heart from upper body.
Smooth muscles in veins - help squeeze blood back to heart.
Give an example of muscles performing a skeletal pump
Gastrocnemius & soleus
What is meant by Oxyhaemoglobin dissociation?
The release of oxygen from oxyhaemoglobin to the tissue (muscle)
What does the Oxyhaemoglobin dissociation curve present?
The relationship between oxygen and haemoglobin. How haemoglobin in our blood carrier and releases oxygen.
Explain the term ‘Arterio-venous difference’ A-VO2 diff
The difference between the oxygen content of the arterial blood arriving at the muscle, and the venous blood leaving the muscles (deoxygenated blood)
During a football game a player’s arterio-venous oxygen difference (a-vO2 diff) will increase. What is the significance of the increase in a-vO2 diff to the player?
During a football game (exercise), the players A-VO2 diff will increase as more oxygen is needed from the blood for the working muscles. This results in more oxygen being taken in during gaseous exchange (at the alveoli) and more carbon dioxide being removed.
Increase in right atrial pressure ______ venous return
Decrease in right atrial pressure ______ venous return
Increase in right atrial pressure DECREASE venous return
Decrease in right atrial pressure INCREASES venous return
