Cardiac system Flashcards
Define diastole
The relaxation phase of the cardiac cycle. This is where the ventricles fill with blood.
Define systole
The contraction phase of the cardiac cycle. This is where the ventricles contract and the blood is pumped through and out of the heart.
Define stroke volume
The volume of blood that leaves the heart in a single contraction.
Define health
A state of mental, physical and social well-being and not merely the absence of disease and infirmity/injury.
Define fitness
The ability to meet and cope with the demands of the environment.
Define physical activity
The ability to be active and take part in exercise, which benefits an individual’s physical, mental and social well-being.
Define heart rate (HR)
The number of times the heart beats per minute.
Define anticipatory rise
A slight increase in heart rate usually just before physical activity due to expectation to exercise (adrenaline/anticipation.)
Define cardiac output (Q)
The amount of blood the heart pumps out (measure in L/min.)
What is the equation for working out cardiac output?
cardiac output = stroke volume x heart rate
Q (L/min) = SV (L) x HR (bpm)
How does exercise improve your physical health?
- decreased resting heart rate due to hypertrophy of the cardiac muscle (can pump out more blood in a single contraction.)
- more red blood cells developed (more oxygen able to be transferred around the body.)
- stronger lungs
less risk of developing diseases like CV disease, type 2 diabetes, metabolic syndrome, some cancers - influences life span
- increased metabolism + more energy used to repair muscles etc
What are the differences between trained and untrained individuals?
Trained:
- high altitude training = more red blood cells + haemoglobin than untrained people
- endurance training = cardiac hypertrophy + increase in chamber size = bigger SV = bigger Q = decrease in resting HR
- trained SV = 130-150ml
- endurance SV = 180 ml
- trained = bradycardia (resting HR <60 bpm)
- lower resting HR, lower HR sub-max, slower HR increase, faster return to resting HR
Untrained:
- genetic factors can make you particularly good at sport (however can be improved by training)
- untrained SV 112ml
- untrained / average HR = 70 bpm
Recite the pathway of blood
1 deoxygenated blood returns to the heart, through the VENA CAVAE…
2 blood fills the RIGHT ATRIUM before going through the…
3 TRICUSPID VALVE and into the…
4 RIGHT VENTRICLE which pumps the blood through the…
5 PULMONARY SEMILUNAR VALVE to prevent backflow and the blood carries on travelling through the…
6 PULMONARY ARTERY, out of the heart, towards the…
7 LUNGS to deposit any CO2 and to collect any O2 to bring back to the heart, through the…
8 PULMONARY VEIN, which takes the newly oxygenated blood to the…
9 LEFT ATRIUM, before travelling through the…
10 BICUSPID VALVE and into the…
11 LEFT VENTRICLE, where the blood fills up and cardiac muscle forces the blood through the…
12 AORTIC SEMILUNAR VALVE so there is no backflow and the blood can continue moving to the…
13 AORTA and out into…
14 the rest of the BODY to the WORKING MUSCLES.
Recite the order of the cardiac conduction system
1 the SAN fires, which causes…
2 ATRIAL SYSTOLE, which is the contractions of the atria and this then triggers the…
3 AVN TO FIRE, carrying the electrical impulse to the…
4 BUNDLE OF HIS and then this impulse diverges into the…
5 BUNDLE BRANCHES so that there is electricity running in both sides of the heart. Once this travels up the branches, the impulse comes into contact with the…
6 PURKINJE FIBRES and as soon as this happens, this triggers…
7 VENTRICULAR SYSTOLE and that is when the final contraction occurs, so the blood can leave the heart.
Define cardiac cycle
The mechanic event of one heartbeat
Define atrial systole phase
Valves forced open, both atria contract and remaining blood is forced into ventricles.
Define atrial diastole phase
Valves shut, both atria relax and fill with blood
Define ventricular systole phase
Ventricles contract, increasing pressure within these chambers, forcing blood towards lungs/working muscles
Define ventricular diastole phase
Ventricles relax, filling with blood
Define myogenic
The ability of a tissue to produce its own impulse
Define anticipatory rise
A slight increase in heart rate, caused by the brain’s response to the body’s need to prepare for exercise
List the short term effects of exercise + why this occurs
- increase in heart rate, rise in adrenaline levels
- increased stroke volume, stronger ventricular contractions
- increased cardiac output, increase in both hr and sv
List the long term effects of exercise
- lower resting heart rate
- more red blood cells reduced
- increased metabolism + more energy to repair muscles etc
- stronger lungs
What is the cardiac control centre?
Located in the medulla oblongata, it is stimulated by chemoreceptors, proprioceptors and baroreceptors.
What is the role of a chemoreceptor?
located in the aortic arch and carotid arteries and detect an increase in CO2 levels in the blood, and therefore increase heart rate
What is the role of a baroreceptor?
located in tissues in the pulmonary vessels, carotid sinus, the heart and aortic arch and detect a change in blood pressure, to then increase / decrease heart rate
What is the role of a proprioceptor?
located in muscles, tendons and joints to detect an increase in muscle movement, to then increase heart rate
What is part of the central nervous system?
brain and spinal chord
What is the role of the peripheral nervous system?
consists of nerve cells that transmit information to the CNS
Define adrenaline
a stress hormone released by sympathetic and cardiac nerves during exercise, that increases heart rate
What is the vasomotor control system?
within the medulla oblongata, it regulates blood pressure throughout the body, through vasodilation and vasoconstriction
What is plasma?
fluid part of the blood, mainly water, that surrounds blood cells and transports them.
Define haemoglobin
iron-filled pigment in red blood cells that binds with oxygen to form oxyhaemoglobin.
What is the role of myoglobin?
- large quantity within slow-twitch muscles (skeletal and cardiac)
- transports oxygen from muscle cell surface membranes, to the mitochondria, for aerobic respiration
- extra reserve of oxygen to ensure exercise lasts longer without fatigue
- used to diagnose acute myocardial infarction
When fully saturated, how many oxygen molecules can haemoglobin carry?
4
Approximately, how much oxygen taken in is saturated with haemoglobin and where does the rest go?
- 97% = oxyhaemoglobin
- 3% = dissolves into blood plasma
What is the Bohr effect?
- the shift to the right on the oxygen dissociation graph
- caused by increase in CO2 levels, increased blood acidity and an increase in body temperature
- does this because these factors show the lack of oxygen in the blood; not enough to meet the demand of it during exercise
- graph shows how much of the partial pressure of oxygen is saturated with haemoglobin
