Heart Structure

Question 1

what is the heart made up of ?

Answer 1

cardiac muscle

Question 2

cardiac muscle can beat/contract without any nervous stimulation (on its own), what is this called?

Answer 2

myogenic

Question 3

How is cardiac muscle myogenic?

Answer 3

• these muscle cells are able to depolarize / generate their own electrical impulses.

Question 4

what is the left and right side of a heart seperated by?

Answer 4

• a septum
• each side consists of an upper atrium and a lower ventricle

Question 5

what is the path of blood through the heart and lungs starting from the vena cava?

Answer 5

• deoxygenated blood returns from the body through the vena cava into the right atrium
• blood then goes thru av valve called a tricuspid valve into right ventricle
• blood then goes up and out semi lunar valve in the middle into the pulmonary artery
• blood then passes through lungs and gets oxygenated
• it returns through pulmonary vein to left atrium
• blood then passes through av valve called bicuspid valve into left ventricle
• it then goes through semi lunar valve in the middle to aorta which transports blood around body

Question 6

what is the role of coronary arteries?

Answer 6

• they branch off from the aorta and supply the heart muscle with blood
• if these become blocked by a build-up of fatty plaques, a person may develop coronary heart disease

Question 7

why is the left ventricle thicker than the right ventricle?

Answer 7

• the left ventricle pumps blood thru a much larger number of capillaries around the body so it requires more pressure therefore there are more muscle fibres to carry out greater contraction
• whereas the right ventricle only pumps blood thru the pulmonary arteries

Question 8

summarise flow of blood through heart starting from vena cava

Answer 8

vena cava - right atrium - tricuspid valve - right ventricle - semi lunar valve - pulmonary artery - lungs - pulmonary vein - left atrium - bicuspid valve - left ventricle - semi lunar valve - aorta - body