Heart

Question 1

What are the two types of blood circulation in the body

Answer 1

Systemic : blood from the heart is distributed round the body before returning back to the heart

Pulmonary : blood from the heart to the lungs & back to the heart

Question 2

What are the three main types of blood vessels in the body

Answer 2

Arteries
Veins
Capillaries

Question 3

What are the three layers of most blood vessels

Answer 3

Tunica externa: elastic & collagen fibres, contains nerves & small blood vessels that supply the walls of large blood vessels

Tunica media: layer of smooth muscle that controls blood vessel diameter

Tunica intima: made of endothelium, protects vessels walk & secretes chemicals, direct contact with blood

Question 4

What is the portal circulation known as the hepatic first pass

Answer 4

Where the venous blood passes from the digestive tract, spleen & pancreas directly to the liver.
The vessel that carries the absorbed substances is called the “portal vein”

Question 5

What is the function of the coronary artery

Answer 5

Delivers oxygenated blood to the myocardium (to allow continuous contraction)

Question 6

Four chambers of the heart

Answer 6

Right atrium
Right ventricle
Left atrium
Left ventricle

Question 7

What is the foramen ovale

Answer 7

Found within the interarterial septum, is a depression called the ‘fossa ovalis’
In foetal development, it would shunt blood from right atrium to left atrium to bypass the lungs

Question 8

What is the ductus arteriosum

Answer 8

During foetal life, a temporary blood vessel that shunts blood from the pulmonary trunk to the aorta
Closes after birth to form ligamentum arteriosum

Question 9

What is the effect of the sympathetic nervous system on the heart

Answer 9

Deals with alarm states
Increases rate & strength of contraction
Causes vasoconstriction thus increase in blood pressure

Question 10

What is the effect of the parasympathetic nervous system on the heart

Answer 10

Relaxitive effect
Decreases rate & strength of contraction via ‘vagus’ nerve
Has little influence on blood vessels themselves

Question 11

What is the sinoatrial node

Answer 11

Part of the conduction system of the heart
The pacemaker of the heart - sets rate & rhythm
Initiates cardiac conduction & is located in the right atrial wall
SA node propagates through each atria via gap junctions & causes atrial contraction

Question 12

What is atrioventricular node

Answer 12

A ‘relay station’ which conducts impulses at a slightly slower rate to allow the atria to finish contracting
Loacted in the bottom right of the interarterial septum

Question 13

What is the Atrioventricular bundle (of his)

Answer 13

Connected to atrioventricular node

Sends action potential down from atria to ventricles

Question 14

What is the function of the right & left bundle branches

Answer 14

From the bundle of his, the action potentital enters the left & right branches which extend interventricular septum towards the apex of the heart

Question 15

What is the function of the purkinje fibres

Answer 15

Rapidly conduct the action potential from the apex of the heart up the remainder of the ventricular myocardium causing ventricular contraction
Moves from apex to top to move all the blood out of the heart preventing clots

Question 16

What is an Electrocardiography (ECG)

Answer 16

Action potentials generate electrical currents that can be detected on the surface of the body
An ECG amplifies & monitors these signals
First wave = P wave which represents atrial depolarisation (from SA node)
QRS wave = rapid ventricular depolarisation (sharp curve)
T wave = ventricular repolarisation (resting)