The heart Flashcards
What muscle does the heart consist of and what is it?
Cardiac muscle, doesn’t fatigue like skeletal muscle
Its myogenic, meaning it can contract in regular rhythm + it determines itself
Where does the heart get oxygen for respiration from?
Coronary arteries deliver oxygenated O2
Coronary veins take deoxygenated O2 away
What is the heart surrounded by + whats its function?
Inelastic pericardial membranes, around outer surface of heart, protects it
Prevents the heart from changing shape as it fills with blood
What are the 4 chambers that the heart consists of?
- Atriums = found at top of heart
- Ventricles = found at bottom of heart
Septum divides left + right sides of heart so oxygenated + deoxygenated blood doesn’t mix
Why is the septum not fully developed until after birth?
In the fetus, the blood is oxygenated in placenta, not lungs, so blood in both sides is similar
The pulmonary circulation is redundant
What happens in the first few days after birth?
Septum closes to stop mixing of the blood
This is be ayse pulmonary circulation is now needed
What does it mean if a hole remains where the septum should be?
Referred to as a “hole in the heart” or a septal defect
Does a hole in the heart have any implications?
Small hole may not have implications, but a large hole can have many implications
Label the different parts of the heart:
Look in camera roll at diagram
What are the atrioventricular valves (av)?
As blood flows in, pressure builds up until valve opens to let blood pass into right ventricle
Sit in between right atrium + ventricle
What are the semilunar valves?
Right ventricle contracts + lets deoxygenated blood in + into pulmonary artery, prevents backflow of blood into heart
What is the purpose of valves?
To stop blood flowing backwards, ensuring undirectional flow
Whether valves are open or closed depends on pressure infront + behind valves
High pressure infront = open
Low pressure infront = closed
What do tendinous cords do?
Makes sure valves aren’t turned inside out when pressure exerted whilst ventricle contracts
What is the bicuspid valve?
In between left atrium + left ventricle, when open it lets blood into the left ventricle that then gets pumped into aorta
