The Heart

Question 0

Umbilical vein

Answer 0

Oxygen and nutrients are received from the placenta via the umbilical vein.

Question 1

What are the three layers of the heart wall called?

Answer 1

Epicardium
Myocardium
Endocardium

Question 2

Ductus arteriosus

Answer 2

Connects pulmonary artery to arch of aorta

Question 3

Ductus venosus

Answer 3

Connects umbilical vein to inferior vena cava

Question 4

Foramen ovale

Answer 4

Connects right and left atria

Question 5

Elastic arteries

Answer 5

Eg aorta, brachiocephalic, common carotid.
Thick tunica media with many elastic fibres.
Withstand changes in pressure and ensure continuous blood flow.

Question 6

Arterioles

Answer 6

1-2 layers of smooth muscle in tunica media. Resistance vessels. Capable of vasoconstriction and vasodilation.

Question 7

Muscular arteries

Answer 7

Most named arteries.
Distribute blood to muscles and organs.
Thick tunica externa.
Lots of smooth muscle in tunica media.

Question 8

Types of capillaries

Answer 8

Continuous
Fenestrated
Sinusoids

Question 9

Capillaries

Answer 9

Function: gas, nutrient and waste exchange

Structure: thin walled, endothelial layer and basement membrane

Question 10

Fibrous pericardium

Answer 10

Inelastic sac of dense connective tissue that wraps around the heart. Prevents overfilling.

Question 11

Serous pericardium

Answer 11

Two layers: parietal and visceral - separated by pericardial cavity which contains serous fluid. Prevents friction.

Question 12

Fibrous skeleton of heart

Answer 12

Bands of fibrous connective tissue that separate the atria from the ventricles. Encircled the pulmonary trunk, aorta and heart valves. Heart valves are attached to the fibrous skeleton.

Question 13

Branches of left coronary artery

Answer 13

Anterior interventricular

Circumflex

Question 14

Branches of right coronary artery

Answer 14

Marginal artery

Posterior interventricular

Question 15

Where do the cardiac veins drain into?

Answer 15

Most drain into the coronary sinus which empties into the right atrium.
The anterior cardiac veins drain directly into the right atrium.

Question 16

Starlings law

Answer 16

The more cardiac myocytes are stretched, the more forceful they contract.

Question 17

End diastolic volume

Answer 17

Preload is determined by end diastolic volume. End diastolic volume is determined by venous return. Venous return is determined by the volume of circulating blood.

Question 18

Venous return is aided by …?

Answer 18

1. Pressure gradient between veins and head.
2. Respiratory pump.
3. Skeletal muscle pump.
4. Gravity.

Question 19

Stroke volume

Answer 19

Volume of blood ejected per beat.

SV = EDV - ESV

Question 20

Forcefulness of contraction is increased by…?

Answer 20

Adrenaline and noradrenaline (SNS).

Hypercalcaemia.

Question 21

Forcefulness is decreased by…?

Answer 21

Hyperkalaemia.
Hypocalcaemia.
Myocardial hypoxia.
Myocardial hypercapnia.