Lecture 7 - The Heart

Question 1

The heart: what is it and where is it located?

Answer 1

Cone-shaped, muscular pump

Located in the thorax between the lungs (in the cardiac notch of the left lung) and is located between ribs 2-5 and is protected by the sternum and ribs

Question 2

Pericardium: what is it and what does it do?

Answer 2

Covers the heart and is composed of an outer fibrous layer and an inner serous pericardium

Protects the heart, anchors it in place, and prevents friction with other tissues and organs

Question 3

The fibrous layer of the pericardium: what is it made of and what does it connect to?

Answer 3

Inelastic, made of dense connective tissue

Fused inferiorly with the diaphragm and superiorly with the great vessels

Question 4

The serous layer of the pericardium: what is it made of and what does it do?

Answer 4

Made of visceral, pericardial, and parietal pericardium.

Prevents friction in the heart

Question 5

Visceral pericardium

Answer 5

Adheres to the heart

Question 6

Pericardium cavity

Answer 6

Lines the inner surface of the
fibrous pericardium

Question 7

Pericardial cavity: what is it?

Answer 7

The potential space between the parietal and visceral layers

Contains fluid

Question 8

Heart wall

Answer 8

Endocardium, myocardium, and epicardium.

Question 9

Endocardium

Answer 9

The inner layer of the heart wall

Question 10

Myocardium

Answer 10

Cardiac muscle positioned between endocardium and epicardium

Question 11

Epicardium

Answer 11

Visceral pericardium

Question 12

Fibrous skeletal of the heart

Answer 12

The heart has bands of fibrous tissue that separate the atria and ventricles electrically

Question 13

Types of valves in the heart

Answer 13

Atrioventricular valves - Prevents backflow from the ventricles to the aorta

Semilunar valves - Prevents backflow back into the pulmonary vein/aorta

Question 14

Atrioventricular valves: what do they do, how does contraction work, and examples of the valves?

Answer 14

Each valve opens/closes when the pressure in the atrium is higher/lower than the ventricle it is connected to.

The contraction of the papillary muscle controls valves.

Tricuspid (R) and bicuspid/matrial (L) valves

Question 15

Semilunar valves: when are they open/closed and what examples?

Answer 15

It opens when the ventricles pump blood as the pressure forces it open

As ventricular pressure falls, blood begins to backflow but the blood first pools in cusps which makes the valves close

Aortic and pulmonary valve

Question 16

Tricuspid valve

Answer 16

Between the right atrium and ventricle, prevents backflow from the right ventricle into the right atrium

Question 17

Bicuspid/matrial valve

Answer 17

Between the left atrium and ventricle, prevents backflow from the left ventricle into the left atrium

Question 18

Aortic valve

Answer 18

prevents backflow from the aorta into the left ventricle

Question 19

Pulmonary valve

Answer 19

Prevents backflow from the pulmonary artery into the right ventricle

Question 20

The heart receiving blood: how much, when, and from what?

Answer 20

250 ml/m

Supplied to the myocardium during the relaxation of the ventricles

The left side of the heart is supplied from the left coronary artery (circumflex, anterior interventricular)

The right side of the heart is supplied from the right coronary artery (marginal, posterior interventricular)

Question 21

Right atrium blood supply from the cardiac vessels

Answer 21

The great, middle, and small cardiac veins drain into the coronary sinus which supplies blood to the right atrium

The anterior cardiac veins drain directly into the right atrium

Question 22

Cardiac conducting system: what does it do, how does it do it, and what are examples?

Answer 22

Controls heart contraction

Initiates electrical impulses that cause the heart to contract

SA and AV node, AV bundle (of His), bundle branches, Purkinje fibres

Question 23

Foetal circulation: the differences with normal circulation

Answer 23

Since nutrients and oxygen are received from the placenta, there is no need for the lungs so the blood circulation is averted from the lungs and the liver

Question 24

Foetal circulation: the three blood shortcuts

Answer 24

Foramen ovale - connects the right atrium to the left atrium so that less blood is sent to the right ventricle (which would pump to the lungs)

Ductus arteriosus - connects the pulmonary trunk to the aorta so that less blood is sent to the lungs

Ductus venosus - connects the inferior vena cava and umbilical vein and this sends less blood through the liver

Question 25

Foetal circulation: how it changes after birth?

Answer 25

Foramen ovale - closes because of the increased pressure in the LA, it then becomes the fossa ovalis

Ductus arteriosus - as the baby takes its first breaths, the lungs expand and oxygen levels rise and this constricts it, closing it and making it now the Ligamentum arteriosum

Ductus venosus - umbilical cord dries and the vessels close, making the DV become the Ligamentum venosum