BIOLOGY - CARDIOVASCULAR SYSTEM Flashcards
What does the cardiovascular system consist of?
Heart
Blood vessels
Blood
What is the function of the cardiovascular system?
To transport important substances around the body for example, oxygen glucose
What is the function of the heart?
Pumping blood around the body
What is a double circulatory system
Blood passes through the heart twice per cycle
What is pulmonary circulation?
The blood passes through the heart and is pumped to the lungs then returns back to the heart
What is mass flow?
Blood moves around the body due to the pressure difference between the pressure in the heart and the pressure in the vessels
What is myogenic?
When the cardiac muscle beats without any nervous stimulation
What is the heart pump made of?
Cardiac muscles
What happens when the heart contracts without any nervous stimulation?
The muscle cells are able to depolarise and generate their own electrical impulses
How much chambers does the heart have?
Four
What is the left and right side of the heart separated by?
Septum
what is the order the heart works
1- deoxygenated blood returns from vena cava, and enters the right atrium
2- then the blood passes into the right ventricle and out into the pulmonary artery
3-the blood now passes through the lungs and returns to the left atrium by the pulmonary vein
4-the blood passes into the left ventricle and then into the aorta, and then onto the body tissues
What does the coronary arteries do?
Supplies the heart muscle with blood
Where does the right ventricle push blood to?
Through the pulmonary arteries only
What do valves do?
Maintain high blood pressure and prevents the backflow of blood
What causes valves to open and close?
Pressure differences on each side of the valve
What are atrioventricular valves?
They are between the atria and ventricle and prevent backflow blood during ventricular systole
What does it mean when the atrio ventricular valves open
Greater pressure in atria, rather than the ventricles
What does it mean when the atrioventricular valves close?
The greater pressure in the ventricles than the atrium
What is diastole?
The heart at reat
Where is the cardiac muscle found?
In the heart
Name the
Structure of the cardiac muscles
It is striated
Contracts without stimulation
The cells are branched to allow faster signal
What does the cytoplasm do?
Allows for rapid movement of ions, and also has a low electrical resistance
What does the shape of the cardiac muscle allow?
A wave of depolarisation to pass through the cells and allows the cells to contract as one
Why are calcium ions needed?
To allow a wave of depolarisation to pass through cells
Why does cardiac muscle have mitochondria?
Because they are reliant on aerobic respiration
Name differences between cardiac muscle and the skeletal muscle
Cardiac- has more mitochondria and a long contraction period and refracts
Unlike skeletal, the heart tissue does not become fatigued, and they are less wide than skeletal muscle fibres
What is the cardiac output?
The volume of blood pumped out of the left ventricle per minute
What is the formula for cardiac output?
Stroke volume X Heart rate
Where does the internal pacemaker start?
At the sinoatrial node
Why is there a pause before the pulse reaches the wall of ventricle?
To allow the blood in the atria to empty completely into the ventricles before the ventricles pump out the blood
What is the bundle of his?
Fibre that transmit signals down septum
What is the purkinje fibres
Fibres that transmit signals up around ventricles
how does the impulse travel
Impulse is produced at the pacemaker at the sinoatrial node
Then the atrioventricular node produces the second impulse
Then the bundle of his transmits the signal down the septum
The purkinje fibres transmit signals up and around the ventricles
What is the electrocardiogram?
The electrical impulses in the heart produce electrical currents that flow through the body
What is the heart rate at rest for a typical human adult
70 bpm
What happens during the cardiac cycle?
Blood enters the atrium
Atrium muscle contract
Blood enters the ventricle
Ventricle muscles contract
Blood enters aorta
Ventricle muscles relax
Blood enters atrium
What do all blood vessels have?
A thin and smooth layer of cells called endothelium
What do arteries do?
Transport blood from heart to organs
What is the structure of arteries?
The walls
Narrow lumen
Large amount of elastin in arterial walls
Many muscles to withstand high pressure
Outer walls made of fibrous proteins to give support to wall
How many walls does capillaries have?
Only has one endothelial layer which is one Cell thick
Why does the capillaries have thin walls?
Increases the rate of diffusion
Why are the capillaries branched?
Increases the overall surface area for diffusion
Why does the capillaries have a neural lumen?
To help increase the rate of diffusion
Name the features of the capillary
One cell thick
Diameter is very small
Creates friction and high surface area
What do the veins do?
Carry blood back to the heart from tissues
What is the structure of veins?
Large lumen for lower resistance
Thinner muscle layer
Thinner elastic layer as pressure is low, and the wall does not need to stretch
How is the flow in the arteries?
Flow is fast and pressure is high
How is the pressure in the veins?
Pressure is low and the flow is slow and non pulser
What factors increase the risk of cardiovascular disease?
Genetics
Age
Gender
Diet
How does genetics increase the risk of cardiovascular disease?
If you have found history of cardiovascular disease, then the chance is also increased
How does age affect cardiovascular disease?
As you get older, your risk of cardiovascular disease increases
How does gender increase the risk of cardiovascular disease
Men are more likely to get cardiovascular disease
How can diet increase the risk of cardiovascular disease
Consuming high levels of saturated fat, high intake of salts, limited intake of healthy fats and vitamins will increase risk of CVD
How can smoking increase the risk of cardiovascular disease?
Affect heart rate
Carbon monoxide in smoke can impact the oxygen carrying capacity of haemoglobin
How does caffeine affect heart rate?
Makes your heartbeat faster by increasing the electrical activity of the SAN node and affect the ventricles, leading to an increase in the rate of contraction and relaxation of each heartbeat
What are the four main blood types?
A
B
AB
O
What happens when antibody binds to an antigen on the red blood cell?
Causes them to clump together
What is the function of coronary arteries?
Supply blood to the heart
What is the sinoatrial node?
Act as a pacemaker by transmitting waves of electrical activity along the walls of the atria at regular intervals
How is electrical activity passed?
From the atria through the atrial ventricular nodes to the bundle of his. Then the bundle of his transmit the electrical activity to the apex of the heart and around the ventricle walls along the purknje fibres
What are bronchioles?
Millions of small branches throughout the lung
What is the alveoli
Sacs that fill with air when you breathe in
What happens during expiration?
The internal intercostal muscles contract and move the ribcage downwards and inwards
This causes the volume of the thoracic cavity to decrease
What are the steps to breathing in?
The external intercostal muscles contract and the diaphragm moves downwards and ribcage moves upwards and outwards
Lung pressure decreases
Air flows down the pressure gradient and into the lungs
Where is the oxygenated blood pump to?
Around the body
Where is deoxygenated blood pump to
To the lungs
What is the coronary arteries?
The heart muscle, which constantly contracts and relaxes, and it supplies blood to the heart
