Section 3- Circulatory system Flashcards
What does double circulation mean?
Blood passes through the heart twice in every circulation of the body
What are the 2 circuits that make up the double circulation system in humans?
- Pulmonary circuit
- Systemic circuit
What are the advantages of having double circulation?
- Oxygenated and deoxygenated blood do not mix
- Allows different blood pressures in the systemic and pulmonary circuits
What is the name of the membranes encapsulated by the heart and what does it do?
Pericardium
Prevents over expansion
What is the name of the walls of the heart?
Myocardium
Cardiac muscle
What does myogenic mean?
The heart is able to generate its own electric activity
What blood vessel joins the right ventricle of the heart to the capillaries of the lungs?
Pulmonary artery
What blood vessel carries oxygenated blood away from the kidney?
Renal vein
What is the first main blood vessel that an oxygen molecule reaches after being absorbed from an alveolus?
Pulmonary vein
What are the names of the valves located between the atrium and ventricle?
Atrioventricular valves
What are the valves for?
Preventing back-flow of blood
What is the aorta?
Connected to left ventricle
Carries oxygenated blood to the body
What is the vena cava?
Connected to right atrium
Brings deoxygenated blood back from the tissues to the heart
What is the pulmonary artery?
Connected to right ventricle
Carries deoxygenated blood to the lungs
What is the pulmonary vein?
Connected to left atrium
Brings oxygenated blood back from lungs to heart
What are the coronary arteries?
The blood vessels that are supplied to the heart muscle
What is the cardiac cycle?
Sequence of events in 1 heartbeat
What are the 2 alternate beating phases of the heart called and what do they mean?
Systole = contraction
Diastole = relaxation
What controls the opening of valves?
Pressure in the relative chambers
What is atrial systole?
Contraction of atrial walls
Relaxation of ventricle walls
Forces remaining blood into ventricles from atria
What is ventricular systole?
Walls of ventricle contract whilst filling with blood
Increases blood pressure
Forces AV valves shut
What is ventricular diastole?
Atria and ventricle are relaxed
Blood returns to atria
As atria fills, pressure rises.
When pressure exceeds ventricles, AV valves open allowing blood into ventricles
SL valves shut as pressure is reduced from relaxation and recoil
When are the AV valves open?
Atrial systole
Diastole