An Overview of the Function of the CVS Flashcards
What does the right side of the heart do?
Pumps blood into the pulmonary circulation to the lungs.
What happens at the lungs?
Gas exchange- oxygen diffuses into the blood and carbon dioxide diffuses out.
What does the left side of the heart do?
Pumping blood into the systemic circulation.
Describe diffusion in the systemic circulation.
Oxygen diffusing from the blood into the tissues and organs.
CO2 diffusing from the tissues and organs into the blood.
List the things that the CVS can transport.
- Oxygen and CO2
- Nutrients
- Heat
- Metabolites
- Hormones
Describe why the heart is very flexible.
Pump can vary output
Vessels can redirect blood
Vessels can store blood
Which vessels store blood?
Veins and venules.
Give an example of the heart varying output.
If exercising, the heart can pump more oxygen around the body.
Give an example of the heart varying output.
If exercising, the heart can pump more oxygen around the body.
Give an example of how the heart can redirect blood.
During exercise, can redirect blood to muscles and legs.
Why is the balance of the heart pumping mechanism of the right and left heart imporatn?
If there was even a slight inbalance, blood would end up in the lungs.
Are pumps in series or parallels?
Series
Are vascular beds in series or parallel?
Parallel
What does the vascular beds being in parallel mean?
They all receive blood at the same time
Also allows for the regional redirection of blood, as previously discussed, like when partaking in exercise.
Which vascular beds are arranged in series rather than in parallel?
Gut and liver
How much is the total cardiac output per minute?
5000ml (5L) / min
Which areas of the body is the cardiac output fairly equal the the oxygen consumption?
Brain, skeletal muscle, abdominal organs.
In which areas of the body is the cardiac output unbalanced with the oxygen consumption?
Skin, heart and liver.
Why is the cardiac output unbalanced with the oxygen consumption in the skin?
Due to thermoregulation as blood is sent out to the skin and heat can be lost from it.
Define cardiac output.
The volume of blood pumped by the heart
Why is the cardiac output unbalanced with the oxygen consumption in the kidneys?
More blood is sent to the kidneys so it can filter out any metabolites.
What does Darcy’s Law state?
Flow= change in pressure
——————————
Resistance
The pressure of the left of the heart varies.
What is this called?
Mean arterial pressure
Does mean arterial pressure increase or decrease with exercise?
Increases
-> This is because more oxygen is required, the heart will push more blood into your arteries, hence increasing mean arterial pressure.
What is the pressure in the right heart referred to as?
Central venous pressure.
How do you work out the difference in pressure?
Mean Arterial Pressure - Central Venous Pressure
What do you need to change in order to increase blood flow?
Resistance
What controls resistance?
Arterioles
Define arteries.
Major blood vessels which carry blood away from the heart
Define arterioles.
Vessels which can change their dimeter to control how much blood travels through the vascular beds.
Define capillaries.
Where the exchange of oxygen and carbon dioxide takes place.
Define veins/venules.
Vessels which store blood,-> when needed, can be forced back into the right side of the heart
Which blood vessel is the smallest?
Capillaries
What is meant by capacitance?
Ability to store electrical charge
What is meant by the fractional distribution of blood?
Proportion of blood that is in these veins and venules versus the rest of your systemic circulation.
Which type of artery is the aorta?
An elastic artery
Which type of artery are regular arteries?
Muscular arteries
Which type of artery are arterioles?
Resistance arteries.
Describe the wall of the aorta.
Thick elastic wall
Describe the wall of arteries.
Strong thick, non-elastic walls
Describe the wall of arterioles.
Thick contractile walls
Describe the lumen of the aorta, arteries and arterioles.
Aorta and arteries= wide lumen
Arterioles= narrow lumen
How many elastic arteries are in the body?
2
Name the two elastic arteries in the body,
Aorta and pulmonary trunk.
What does a wide lumen mean in terms of resistnace?
Low resistance
Describe the lumen of capillaries.
Narrow
Describe the lumen of venules.
Wide lumen
Describe the walls of capillaries.
Thin
Describe the walls of venules/veins.
Thin, distensible*
*able to increase in size and helps to store blood
Why are capillaries good for gas exchange?
They has a high surface area to volume ratio.
Also, very thin, so gases can diffuse easily.
Which vessels are capacitance vessels and what does this mean?
Veins/venules
->able to store blood
Where does the aorta stem from?
Left ventricle
Which structure separates the right and left half of the heart?
Septum
Which section of the heart receive blood from systemic circulation?
Right atrium
Which structure receives the blood returning from the lungs?
Left atrium
What are the right and left ventricles for?
Pumping blood
What happens to the blood after the left ventricle?
Goes into the systemic circulation via the aorta
What structure transports the deoxygenated blood back to the right atria?
Vena cava
What is the difference between the superior and inferior vena cava?
Superior returns blood from above the heart back to the heart,
Inferior returns blood from below the structure of the heart back to the heart.
Where does the blood go after the right ventricle?
It is pumped into the pulmonary circulation.
What does the pulmonary trunk bifurcate into?
Left and right pulmonary artery
What does the right pulmonary artery do?
Pumps blood to right lung
What does the left pulmonary artery do?
Pumps blood to the left lung.
How does the blood return to the left atrium?
Via the pulmonary veins.
How many pulmonary veins are there?
4
Name the four pulmonary veins
Left superior pulmonary vein
Left inferior pulmonary vein
Right superior pulmonary vein
Left inferior pulmonary vein
Name the valve between the left ventricle and aorta.
Aortic valve
Name the valve between the right ventricle and pulmonary trunk.
Pulmonary valve
What happens in systole?
Blood is squeezed from ventricles and into the aorta.
What happens in diastole?
Heart chambers fill with blood.
Name the valve between the right atrium and ventricle.
Tricuspid valve
Name the valve between the left atrium and ventricle.
Mitral valve
What is the role of the tricuspid and mitral valve?
Prevents regurgitation of blood from the ventricle back into the atria.
What prevents the valves from going back on themselves?
Chordae tendineae
Which muscles are chordae tendineae attached to?
Papillary muscles
(ps yes I spelled it right)
The valves open and close due to what?
Changes in poressure of the heart
How many cusps on the tricuspid valve?
3
How many cusps on the mitral valve?
2
How many cusps do the aortic and pulmonary valves have?
3
