The heart (8) Flashcards
What muscle is the heart made of
Cardiac muscle
what is the septums role
it separates the left side from the right side of the heart
What produces the pumping movement of the heart
The regular contraction and relaxation of the cardiac muscles
What are the atrio ventricular valves for
They separate the ventricles from the atrium
Which valve is on the left
The biscupid valve
Which valve is on the right
The tricuspid valve
When do the valves shut and why
When the ventricles contract, so blood cant flow back into the atria
What blood vessels can be seen on the outside of the heart and what do they do
The coronary arteries, they deliver oxygenated blood to the heart walls.
Why are there coronary arteries on the outside of the heart
the heart is so thick (especially around the left ventricle) the muscle on the outside of the heart is too far away from the blood inside the ventricles to obtain o2 from it.
What is a myocardial infection also known as
A heart attack
Why are the atria walls very thin
Theres no need to generate high pressure blood as the blood doesnt need to be pumped far.
Why do the left ventricle walls need to be thicker than the right ventricle wall
The left ventricle needs to pump blood around the body against greater resistance so high pressure blood needed
Why must the blood from the left side of the heart be separate from the blood on the right side of the heart
To not mix the oxygenated blood (left) with the deoxygenated blood (right). If they were to mix the transport of o2 would be less efficient.
Why must the blood pressure be highest in the heart compared to anywhere else in the circulatory system.
To ensure mass flow. Blood will flow from high pressure to low pressure
What is a hole in the heart
a gap in the septum. Before birth the septum isn’t fully developed. After birth it closes, sometimes they dont fully close.the bigger holes = severe health problems.
What is the foremen ovale
a gap in the septum of the heart
With a large hole in the heart what happens
The deoxygenated and oxygenated blood mix, so blood does not carry enough o2 to tissues
What is the role of the tendinous cords in the ventricles
They prevent the AV valves from being turned inside out.
The 3 parts to the cardiac cycle
Diastole,
Atrial Systole, Ventricular Systole
What is diastole
relaxation
What happens in atrial systole
the pressure in the atria rises higher than that in the ventricles, so the valves are pushed downwards by the higher pressure of the blood in the atria.
What happens in ventricular systole
the pressure in the ventricles rose above that of the atria, so the valves are being pushed upwards. they cant flap past their opening as they are anchored by the heart tendons holding them to the heart wall. (pressure in the ventricles rise much higher than in the atria as it has much thicker walls)
Where are the semilunar valves
In the pulmonary artery and aorta
Where are the AV valves
Between the atrium and ventricle
What is a double circulatory system
Blood passes through the heart twice per circuit. The right side pumps deoxygenated blood to the lungs where it becomes oxygenated and then goes back to the heart. The left side pumps newly oxygenated blood around the body.
How does the mammalian double circulatory system work
What is the advantage to mammals having the double circulatory system
It keeps the oxygenated and deoxygenated blood separate, this allows for higher metabolic rates to be maintained as the blood isn’t mixing.
give a detailed explanation of the pressure changes during the cardiac cycle
answer separately in detail on word/paper
give a detailed explanation of the cardiac cycle
answer separately
why is aortic blood pressure always high
thick walls, and elastic
which ventricle has a thinner wall
the right ventricle
what creates the lub-dup sound
the lub is the sound of the 2 AV valves shutting at the same time. and the dup sound is the semilunar valves shutting
when do the semilunar valves shut
when the pressure in the aorta is higher than in the ventricle (when the ventricle relaxes)
why is it important that the atria contract before the ventricles contract
it ensures that the ventricles are filled with blood before they contract.
what individual cells make up cardiac muscle
cardiomyocytes
what are intercalated discs
cardiomyocytes group together to make fibres with the cell to cell boundary
what are 2 adaptations to the heart and why are there adaptations
the cardiac muscle fibres branch, and there’s cross fibres between the fibres.
the cardiomyocytes group together to make fibres with the cell to cell boundary having an intercalated disc.
these adaptations ensure efficient transmission of the contraction through the heart.
why is cardiac muscle special
it never tires - it will continuously contract/relax.
it is myogenic - it doesn’t need any stimulation from a nerve for it to contract
cardiac muscle will contract independently of the nervous system
what are the walls of the right atrium called
the Sino atrial node
what is the Sino atrial node
a group of specialised cardiac cells, which generate electrical impulses that pass rapidly across the walls of the atria from cell to cell making the atrial walls contract - atrial systole.
so they create atrial contraction.
as muscle in SAN contracts the, it produces an electrical impulse which makes the atrial walls contract (showing up on an ECG as the p wave)
why cant electrical impulses pass from the atria to the ventricle walls
cos there’s a ring of fibrous tissue preventing this
how can electrical impulses pass from atria to ventricles
by a group of specialised muscle cells- the atrio ventricular node (AVN)(which acts as a relay point).
what is the atrio ventricular node
a group of specialised muscle cells
what happens with the impulses after reaching the AVN
they travel down the heart muscle fibres (the bundle of His) that spread down the septum between the ventricles. the impulses then reach the apex of the heart. the fibres then spread throughout the muscular walls in Purkyne tissue. the impulse causes the ventricular systole.
what is the bottom of the heart called
the apex
what is the advantage of impulses passing down from the bundle of His and then up through the Purkyne tissue
the ventricles can contract from the apex. its effective, efficient. it pushes the blood up to the arteries ensuring they are completely empty.
in the correct order which blood vessels will an erythrocyte travel through when it leaves the heart
arteries, arterioles, capillaries, venules
what acts as the pacemaker
the Sino atrial node (it automatically relaxes and contracts, it is myogenic)
what does an ECG do and what does it stand for.
an electrocardiogram measures electrical activity in the heart as it beats.
when do the ups and downs occur on an ECG
before contractions occur as these electrical impulses are what create the contractions of the muscle in the heart walls.
what does a p wave and a t wave on an ECG represent
p wave - the wave of electrical activity spreading through atria walls, which is then followed by the rise in the atria as they contract.
t wave - relaxed state
cause and effect of ventricular fibrillation
ECG shows no patter. the muscle in the ventricle walls flutters, cause - person has suffered myocardial infection (heart attack). effect - no blood circulation, death.
cause and effect of bradychardia
ECG - slower heart rate. cause - SAN not working properly, or ur really fit. effect - tired.
cause and effect or atrial fibrillation
ECG - abnormal heart rate (arrythmia). cause - they don’t contract properly and some are passed onto ventricles which don’t contract often enough
cause and effect of tachycardia
ECG - faster heart rate. cause - fright, anger, exercise.
which side of the heart pumps deoxygenated blood
the right?
