Cardiovascular system Flashcards
Explain the role of;
- Chemoreceptors
- Proprioceptors
- Baroreceptors
Chemoreceptors
1. Located In muscles, aorta and carotid arteries
2. Detects an Increase in Carbon dioxide (C02)
and a decrease in pH levels (Blood acidity)
3. Sends a signal to the sympathetic nervous system, which sends a signal to the Cardiac Control Centre. (The CCC then sends a signal via the sympathetic nerve to the Sino atrio node to increase Heart Rate).
Proprioceptors
1. Are located In muscles/Tendons/spindles/joint receptors
2. Increase in motor activity sends a signal to the CCC to Increase HR and SV
Baroreceptors
1. Located in Aorta and carotid arteries.
2. An increase or decrease in Blood pressure signals the medulla in the brain.
Increased blood pressure decreases the HR.
Decreased blood pressure increases the HR.
Suggest how improved fitness, brought about by regular training, may benefit the health of an individual.
[2 marks]
Award one mark for each of the following points (max 2 marks):
- Reduces weight / fat / less obesity / reduced cholesterol
- Strengthens heart / reduce chance of heart attack / coronary risk factors
- Improved social / mental / physical well-being
Describe how an increase in carbon dioxide in the blood during exercise would lead to an increased breathing rate.
[3 marks]
* Increased blood acidity/decreased blood pH levels. (1)
* Detected by chemoreceptors. (1)
* Impulse sent to the respiratory centre/medulla. (1)
* Increased impulses to respiratory muscles to contract faster. (1)
Accept named respiratory muscles including diaphragm/intercostal muscles/scalene/ sternocleidomastoid/pectorals/abdominals.
Accept any other appropriate description of how an increase in carbon dioxide in the blood during exercise would lead to an increased breathing rate.
Max 3 marks
(1) A high percentage of body fat can have a negative impact on health and fitness. Define the terms health and fitness.
(2) Other than diet, explain how two different lifestyle choices can have a negative impact on health.
(i) A Health – social, mental and physical well-being and not merely the absence of disease.
B Fitness – the ability to carry out everyday tasks without undue fatigue/the ability to the meet/cope with the demands of the environment
(ii) A Smoking – reduces lung/oxygen transport capacity/causes lung cancer/heart disease/stroke
Accept any named disease.
B (Lack of) exercise – obesity/reduced flexibility/strength/mobility issues /increased blood pressure/heart disease/diabetes
Also accept inactivity or equivalents for exercise.
C Alcohol/drugs – damages liver/heart disease/cancer/diabetes/depression
D Work-life balance – stress
E (Lack of) sleep – fatigue/stress
F Over-training – long term injury
Do not accept answers relating to diet, eg supplements or fitness
Performers in team games such as netball need to be suitably prepared to meet the demands of the game.
(i) In order to play netball effectively, performers need to be fit. What do you understand by the term fitness? (1 mark)
(ii) Discuss whether you must be healthy in order to be fit. (2 marks)
(i) Fitness- Ability to meet everyday demands of the environment to cope.
(ii) Healthy – social, mental and physical well-being. E.g the absence of loneliness, disease or mental illness like depression.
An athlete may be healthy as they do not have cancer or depression. However, they may be unfit as they lack cardiovascular endurance. For example they may be a PE teacher who is unable to deliver a lesson without becoming fatigued due to their poor Cardiovascular endurance.
Describe how the cardiac conduction system causes the heart to contract.
[3 marks]
* The sino-atrial node (SAN) (the pace maker of the heart) sends an impulse/electrical signal through the walls of the atria (1)
* Spreads as a wave of excitation (1)
* This causes atrial systole / atria contract (1)
* The impulse then passes to the atrio-ventricular node (AVN), (which delays the impulse (for around 0.1 seconds, enabling atria to fully empty) (1)
* The impulse passes down the Bundle of His (in the septum of the heart), to the Purkinje fibres in the (walls of) the ventricles (1)
* Ventricular systole then occurs / ventricles contract (1).
Students must refer to the system in order.
Outline two ways an active lifestyle can reduce the risk of heart disease.
[2 marks]
* Decrease in cholesterol/Low density Lipoprotein/fat in coronary arteries (1)
* Lower blood pressure (1)
* Stronger heart/cardiac hypertrophy/higher stroke volume (1)
Do not accept decrease in HDL.
Accept any other appropriate outline of how an active lifestyle can reduce the risk of heart disease.
Describe how heart disease can result in a heart attack. [ 2 marks]
* Hardening of coronary arteries/build-up of plaque/cholesterol/fat in the coronary arteries/atherosclerosis/arteriosclerosis (1)
* Causes blockage/blood clot (1)
* Limiting the supply of oxygen to the heart/angina (1)
Accept any other appropriate description of how heart disease can result in a heart attack.
Stateonepositive effect that high density lipoproteins have on the body.
(Total 1 mark)
* Remove excess cholesterol (1)
* Transport excess cholesterol to the liver (1)
* Protect the artery walls against LDL cholesterol / an anti-inflammatory effect (1)
* Help protect blood cells and important chemical messengers in the blood from being broken down by the liver / positive anti-oxidant effect (1)
* Reduce the risk of heart disease (1)
Accept first answer only.
Accept any other positive effect that high density lipoproteins have on the body.
- What can cause a stroke
- What can cause Coronary heart disease
- A stroke occurs when the blood supply is cut off to the brain. This can lead to a disability or death.
- CHD occurs when arteries harden and narrow due to a build up of fatty cells. This process is called atherosclerosis.
Describe what is meant by blood pressure and explain the different between Diastollic and Systollic pressure
Firstly, blood pressure refers to the force exerted by the blood against the wall of the blood vessels. This can be referred to by blood flow x resistance.
When the ventricles contract SYSTOLIC PRESSURE forces blood from the heart.
When the ventricles relax DIASTOLIC PRESSURE allows blood to enter the heart.
Explain the difference between LDL (Low density Lipoprotein) and HLD (High denisty Lipoprotein) cholesterol
There are two types of cholesterol. Low density lipoprotein (LDL) and High density lipoprotein (HDL).
LDL is classed as bad cholesterol as it transports cholesterol/plaque in the blood to the tissues. This increases the chance of CHD.
HDL is classed as good cholesterol as it transports cholesterol in the blood to the liver, where it is broken down.
HDL can reduce the chance of coronary heart disease, heart attack and kidney failure and protect the artery walls against LDL.
Explain how the heart controls the rate at which it beats.
[4 marks]
- The heart generates it’s own electrical and nerve impulse, meaning it myogenic.
- The Sino atrial node generates an electrical impulse (like a mexican wave) to cause the heart to beat (The SAN is often referrred to as the pacemaker).
- The SAN causes systole which is when the heart contracts
- The Atrio ventricular (AVN) node recieves the eltrical impulse for the SAN, The AVN causes a slight 0.1 second delay to allow the atria to contract, which allows a diastollic contraction (when the heart fills with blood).
- The eletical impulse then passes through the bundle of HIS, which is a collection of cardiac cells that spread to two bundle branches.
- The elctrical impulse then moves into Purkinje Fibres, these small muscle fibres spread to the ventricles, causing them to contract.
Explain the role of the atrioventricular node in the cardiac conduction system.
[3 marks]
* Receives impulse from sinoatrial node (1)
* Delays (transmission of) impulse (1)
* To allow ventricular filling/enable the atria to fully contract (1)
* Sends impulse down septum/through bundle of His/to purkinje fibres (1)
Accept any other appropriate explanation of the role of the atrioventricular node in the cardiac conduction system.
Max 3 marks
Describe the role of the sympathetic and parasympathetic nervous systems in the regulation of heart rate.
[3 marks]
* Medulla/cardiac control centre sends impulse to the Sino-atrial node (SAN)/pacemaker. (1)
* Sympathetic nervous system increases heart rate. (1)
* Sympathetic impulses travel down the sympathetic/accelerator nerve. (1)
* Parasympathetic nervous system decreases heart rate. (1)
* Parasympathetic nervous systems travel down the vagus nerve. (1)
Accept any other appropriate description the role of the sympathetic and parasympathetic nervous systems in the regulation of heart rate.
Maximum 3 marks
Heart rate is controlled by the cardiac conduction system.
Which one of the following is the order of the cardiac conduction system?
[1 mark]
A
Atrioventricular node, sinoatrial node, bundle of His, Purkinje fibres
B
Atrioventricular node, sinoatrial node, Purkinje fibres, bundle of His
C
Sinoatrial node, atrioventricular node, bundle of His, Purkinjie fibres
D
Sinoatrial node, atrioventricular node, Purkinje fibres, bundle of His
C
During a game of football, a player’s heart rate will vary.
Explain how changes in the acidity of the blood cause the heart rate to increase during a game of football.
[4 marks]
Blood’s acidity increases / pH lowers.
Caused by more carbon dioxide being produced.
This is detected by chemoreceptors (must include key term detect)
Nerve messages are sent to the medulla (oblongata) / cardiac (control) centre.
Sympathetic nervous impulses are sent.
To the Sino-Atrio node / SAN/SA node.
Decrease in parasympathetic / vagus nerve impulses.
During a game, a player’s work rate will vary. Describe how the ‘parasympathetic’ and the ‘sympathetic’ nerve pathways control heart rate during a game.
[3 marks]
- Controlled by medulla oblongata/ cardiac centre.
- Sympathetic pathway increases heart rate; due to the release of adrenaline. A signal is sent to SAN to increase the frequency of eletical impulse, this causes an increase in stroke volume.
- Parasympathetic pathway decreases Heart rate due to the release of Acetylcholine. A signal is sent via the vargus nerve.
If endurance events take place in warm conditions, cardiovascular drift can occur.
Analyse how cardiovascular drift may result in lower levels of performance.
[3 marks]
* Athletes will sweat reducing the plasma volume of blood. (1)
* Blood becomes more viscous/thicker which reduces venous return. (1)
* Due toStarling’s lawstroke volume/ejection fraction will decrease. (1)
* Asstroke volume/ejection fractiondecreasesheart rateincreases to maintain/increasecardiac output. (1)
* Having a higher heart rate at a lower than normal intensity increases the athlete’s rate of perceived effort/the performer mentally thinks they are working harder than they are. (1)
Accept any other appropriate analysis of how cardiovascular drift may result in lower levels of performance.
Explain how rising levels of carbon dioxide cause an increase in cardiac output.
[4 marks]
- Increases acidity / hydrogen ion concentration / lowers pH / (in blood);
- Detected by chemoreceptors;
- Impulses / information to cardiac centre / medulla (oblongata);
- Increased stimulation of sympathetic nerve / decreased stimulation of
parasympathetic / vagus nerve - Adrenaline / nor-adrenaline
- To S.A.N. / S.A node / sino-atrial node
- Increase in heart rate
- Increase in venous return
- Increase in stroke volume / ejection fraction
- Starlings Law of the heart.
Explain the cause and effect of high blood pressure
[3 marks]
- Firstly, blood pressure refers to the force exerted by the blood against the wall of the blood vessels. This can be referred to by blood flow x resistance.
- When the ventricles contract SYSTOLIC PRESSURE forces blood from the heart.
- When the ventricles relax DIASTOLIC PRESSURE allows blood to enter the heart.
- High blood pressure puts strain on the arteries and can cause a heart attack, heart failure, kidney disease or stroke.
(i) Explain the term anticipatory rise.
[1 mark]
(ii) Neural control of heart rate involves the autonomic nervous system.
Identify and explain the role of different receptors involved in increasing heart rate.
[3 marks]
(i) Increase in heart rate prior to exercise caused by (the release) of adrenaline.
(ii) Chemoreceptors – detect increase in blood acidity / decrease in pH / increase in CO2 / increase in Hydrogen ion concentration / H+
Proprioceptors / mechanoreceptors – detect movement / muscular contractions
Baroreceptors – detect decrease in blood pressure
Impulses sent to cardiac control centre / medulla (oblongata)
Increase in impulses to the SA node via the sympathetic nervous system / cardiac accelerator nerve
If an athlete performs a continuous exercise session lasting 45 minutes at a sub-maximal pace, cardiovascular drift will occur.
Explain the term cardiovascular drift.
[3 marks]
AIncrease in heart ratedue to / anda decrease in stroke volume / ejection fraction.
donotaccept abbreviations – SV, Q, HR
BOccurs after 10 minutes.
CWarm environmental conditions.
DCaused by a reduction of fluid in the blood / plasma / blood volume / increase in sweating/ blood more viscous.
EVenous return decreases / blood pumped back to heart decreases / reduced atrial filling.
FAims tocool the body(by maintaining cardiac output).
reason for increase in cardiac output explained.
The table below represents heart rate and stroke volume for an untrained performer as intensity of exercise increases.
Explain how and why the components of cardiac output differ for a trained performer at point A.
* Trained athlete would have a lower resting heart rate of below 60 bpm / bradycardia (1)
* The trained athlete has a higher resting stroke volume (more blood ejected per beat) (1)
* Regular training of trained performer leads to cardiac hypertrophy (1)
* This means a trained performer will have stronger heart / more forceful contraction (1).
What’s going on at each letter ?
What type of exercise is happening on each graph?
[2 Marks]
A= Anticipatory rise (caused by adrenaline)
B= Sharp rise in heart rate due to anaerobic work
C= Steady state as the athlete is able to meet the oxygen demand with the oxygen supply
D=Exercise has stopped so heart rate decreases
E=Slow recovery as heart rate remains elevated to remove waste products like lactic acid [EPOC]
D
In response to exercise why does Stroke volume initially increase, then level out, before slightly decreasing? [2 marks]
1.Stroke volume increases to provide oxygenated blood to the working muscles, in response to the demands of exercise.
- Stroke volume will plateau once the athlete is operating at maximum intensity.
3.Stroke volume decreases slightly due to a shortened diastolic phase. Meaning the ventricles do not have as much time to full up with blood before they contract.
The graph below shows the cardiac output, pulse rate and stroke volume of an athlete exercising in a warm environment for 45 minutes.
Consider the effect of prolonged exercise in a warm environment on cardiac output and its components. Refer to the graph in your answer. [3 marks]
AO2 (sub max 2 marks)
* Cardiac output increases during prolonged exercise (1)
* This is because heart rate gradually increases to compensate for a reduction / decrease in stroke volume (1)
* This is known as cardiovascular drift (1)
AO3
* Stroke volume decreases during prolonged exercise in a warm environment because of the fluid lost from plasma (1)
* Cardiac output needs to increase during prolonged exercise in a warm environment to cool the body and to create energy (1)
Accept other appropriate explanations of the effect of prolonged exercise in a warm environment on cardiac output and its components.
Explain the Oxyhaemoglobin disassociation curve, when the athlete is at rest
- As the partial pressure of oxygen in the lungs is high, haemoglobin almost completely saturates with oxygen, because there’s lots of oxygen in the lungs to attach to haemoglobin.
- As haemoglobin moves around the body to tissues, e.g skeletal tissue, the pressure of oxygen begins to decrease.
- Due to this pressure change the haemoglobin DISASSOCIATES (releases) oxygen to the tissues, to compensate for the change in pressure.
- At rest the haemoglobin will give around 23% of it’s oxygen to the muscles. This is sustainable.
Explain what happens to the oxygen disassociate curve due to Bohr’s shift
- During exercise the curve shifts to the right. This is because the demand for oxygen is greater.
Also, Carbon dioxide levels rise when we exercise which changes the pressure. The drop in pressure of oxygen causes the haemoglobin to DISSASOCIATE all of the oxygen it has.
- This phenomenon is known as the Bohr shift and ensures more oxygen is available to the working muscles.
Explain the causes of this change to the curveandthe effect that this change has on oxygen delivery to the muscles.
[4 marks]
Bohr shift [Required term]
Resulting in less saturation / reduced affinity of haemoglobin with oxygen.
Increase in (blood / body) temperature- oxygen disassociates from haemoglobin more readily in warmer climates.
Increase in blood carbon dioxide concentration (pCO2)- oxygen disassociates from haemoglobin more readily if CO2 levels increase rapidly.
Increase in blood acidity / decrease in pH- more CO2 lowers the acidity (ph) levels in our blood, this drop causes oxygen to disassociate from haemoglobin more readily.
An increase in oxygen release / oxyhaemoglobin dissociation to muscles /muscles receive more O2.
Identify and explain the change in blood flow during exercise attwodifferent locations shown in the graph. [4 marks]
Identification of location and change
ACoronary vessels –Increasein blood flow
BSkin –Increasein blood flow
CStomach –Decreaseblood flow
Accept first two locations only.
Must state location for points A, B & C.
Explanation
D(coronary vessels) To allow the heart to beat faster/more powerfully
E(skin)Temperature regulation/get rid of heat/cool down
Not to sweat
F(stomach) Blood redistributed away from stomach to where it is needed
Only credit D, E & F if linked to A, B & C.
(i)Explain how redistribution of blood occurs during exercise. [3 marks]
(ii)Explain why blood flow to the brain remains the same during restandduring maximum effort. [2 marks]
(iii) Using the table above, explain why performers should not eat immediately before exercise. [2 marks]
(i)Increase in CO2levels / acidity / decrease in O2levels / pH / chemoreceptors
Terms need explaining
Movement of joints / tendons / mechanoreceptors / proprioceptors
Vasomotor centre / medulla
Autonomic / sympathetic nervous system / (nor) adrenaline
Pre-capillary sphincters / rings of circular / smooth muscle
Vasodilation to areas needing blood / muscles
Vasoconstriction of areas not needing so much blood / kidneys / liver / gut
(ii)Brain function maintained during exercise
Brain active / working = OK
Oxygen / nutrients required
(iii)During exercise,lessblood goes to the gut / change from 1250 cm3to 375 cm3
Credit use of table to suggest reduced gut blood
But, blood / oxygen needed in gut for digestion of food
‘Unable to digest food’ is incorrect
Less blood / oxygen available to muscles
