Body Systems L7

Question 1

Characteristics of the heart?

Answer 1

• Cone shaped

- Muscular pump.

Question 2

Location of the heart?

Answer 2

• Thorax -> mediastinum (between lungs)
• Protected -> rib cage -> between ribs 2-5
• Behind the sternum
• Left of midline
• Apex -> 5th intercostal space, midclavicular line.

Question 3

What 2 structures work alongside heart?

Answer 3

• Fibrous Pericardium

* Serous pericardium

Question 4

Functions of the Fibrous pericardium?

Answer 4

• Prevents overfilling of heart

- Anchors position

Question 5

Characteristics of the fibrous pericardium?

Answer 5

• Inelastic sac -> dense tissue
• Inferior fusion -> diaphragm
• Superior infusion -> large vessels

Question 6

Functions of the Serous pericardium?

Answer 6

 Prevents friction.

Question 7

Characteristics of the Serous pericardium?

Answer 7

• Double-layered serous membrane

- Lies -> deep within -> fibrous pericardium

Question 8

What are the three components of the serous pericardium?

Answer 8

1. Parietal pericardium
2. Visceral pericardium
3. Pericardial cavity

Question 9

Characteristics of the Parietal pericardium?

Answer 9

 Lines inner surface -> fibrous pericardium

Question 10

Characteristics of the Visceral pericardium?

Answer 10

 Tightly adhered -> surface of heart

Question 11

Characteristics of the Pericardial cavity?

Answer 11

 Space between parietal & visceral layers

-> Contains tissue fluid.

Question 12

What are the names of the three layers of the heart, and what are they composed of?

Answer 12

i)	Endocardium:
	Inner layer -> Endothelium
ii)	Myocardium:
	Middle layer -> Cardiac muscle
iii)	Epicardium:
	Outer layer -> Visceral pericardium

Question 13

Outline Blood flow through heart.

Answer 13

1. Deoxygenated blood from body tissues
   - > Superior & Inferior vena cava -> right atrium
   2. Right atrium
   - > Tricuspid (right atrioventricular) valve -> right ventricle.
   3. Right ventricle
   - > Pulmonary semilunar valve -> pulmonary trunk & arteries.
   4. Pulmonary trunk & arteries
   - > Lungs -> Oxygenated -> Pulmonary veins.
   5. Pulmonary veins
   - > Left atrium
   6. Left atrium
   - > Bicuspid (mitral/left atrioventricular valve) -> Left ventricle
   7. Left ventricle
   - > Aortic semilunar valve -> aorta.
   8. Aorta
   - > Body tissues.

Question 14

What is the ventricular septum?

Answer 14

 Muscular tissue -> dividing heart -> right & left ventricles

Question 15

What is the apex?

Answer 15

 Pointed end of heart

Question 16

State the differing characteristic between the left & right ventricles. Explain why this difference occurs.

Answer 16

• Left ventricular walls
 Much thicker than right ventricular walls
Requires strong muscular walls -> sufficient pressure -> pump blood around body.

Question 17

What is the fibrous skeleton, what is it’s function and where is it located?

Answer 17

• Fibrous Skeleton:

• Bands -> fibrous connective tissue -> Between atria and ventricles.
• Electrically separates atria & ventricles.
• Surrounds pulmonary trunk, semilunar & atrioventricular valves.

Question 18

What is the function of heart valves?

Answer 18

 Prevent backflow of blood

Question 19

Name the atrioventricular valves

Answer 19

• Tricuspid (Right AV) valve

- Bicuspid/mitral (Left AV) valve

Question 20

Name the semilunar valves

Answer 20

• Pulmonary

- Aortic

Question 21

Describe the AV valves

Answer 21

Atrioventricular:
- Tricuspid (Right AV) valve
- Bicuspid/mitral (Left AV) valve
 Between atria & ventricles
 Open -> blood flow -> atria to ventricles
 Anchored -> Chordae tendinae to papillary muscles.
 When ventricular pressure < atrial pressure
 Valve opens -> loose chordae tendinae
 When ventricular pressure > atrial pressure
Valve begins to close -> pulls chordae tendinae -> papillary muscle contracts -> prevents inversion of valve -> backflow of blood.

Question 22

Describe the Semilunar valves

Answer 22

 Guard entrances -> aorta & pulmonary trunk
 Open -> force of blood -> contraction of ventricles
 Bloodflow -> backwards -> aorta & pulmonary trunk -> ventricular relaxation
Accumulates in cusps -> shut.
 Prevent backflow of blood -> ventricles.

Question 23

Where is the blood of coronary circulation delivered to in the heart? Describe what must occur for this.

Answer 23

• 250ml/min blood

Delivered -> myocardium -> ventricular relaxation

Question 24

Name the types of

Left coronary artery (LCA)

Answer 24

Anterior interventricular

Circumflex

Question 25

Name the types of | Right coronary artery (RCA)

Answer 25

Marginal artery | Posterior interventricular

Question 26

Where do most cardiac veins drain & where does this empty?

Answer 26

- Most cardiac veins -> drain -> coronary sinus | Empties -> right atrium

Question 27

What are the other types of cardiac vein (besides most common) and where do they empty?

Answer 27

- Anterior cardiac veins -> drain directly -> right atrium.

Question 28

What is angiography?

Answer 28

- Medical imaging technique | Examines patency (diameter length) of vessels.

Question 29

What is the function of the conducting system & what is it comprised of? What are the function of each of these components & where are they found?

Answer 29

 Sinoatrial (SA) node  Atrioventricular (AV) node  AV bundle (Bundle of His)  Purkinje fibres

Question 30

What is an electrocardiogram?

Answer 30

• Electrocardiogram (ECG) | - Records electrical activity -> heart.

Question 31

Where does the placenta obtain oxygen & nutrients from?

Answer 31

Umbilical vein

Question 32

Why are there 3 shortcuts in foetal cardiac cycles? Name each of these shortcuts.

Answer 32

``` - Bypasses non-functional lungs  3 shortcuts: i) Ductus venosus ii) Foramen ovale iii) Ductus arteriosus . ```

Question 33

What is the Ductus venosus?

Answer 33

A shortcut in the foetal circulatory system between | Umbilical vein -> inferior vena cava

Question 34

What is the Foramen ovale?

Answer 34

A shortcut in the foetal circulatory system between | Right -> left atria

Question 35

What is the Ductus arteriosus

Answer 35

A shortcut in the foetal circulatory system between | Pulmonary trunk -> arch of aorta.

Question 36

Outline the cardiac cycle of a placental foetus?

Answer 36

. Superior & Inferior vena cava -> right atrium 2. Right atrium -> Tricuspid (right atrioventricular) valve -> right ventricle. & -> Foramen ovale -> left atria 3. Right ventricle -> Pulmonary semilunar valve -> pulmonary trunk & arteries. 4. Pulmonary trunk & arteries -> Lungs -> Pulmonary veins. & -> Ductus arteriosus -> arch of aorta 5. Pulmonary veins -> Left atrium 6. Left atrium -> Bicuspid (mitral/left atrioventricular valve) -> Left ventricle 7. Left ventricle -> Aortic semilunar valve -> aorta. 8. Aorta -> Body tissues.

Question 37

What changes occur during birth of placental foetus regarding the circulatory system? What happens as a result of these changes?

Answer 37

1. Newborn takes 1st breath - Lungs expand  Blood rushes into pulmonary circulation O2 levels rise Constricts ductus arteriosus  Less blood from pulmonary trunk -> aorta >> Ductus arteriosus -> Ligamentum arteriosum - Pressure -> Left atrium -> incr. Foramen ovale closes  Fossa ovalis >> Foramen ovale -> Fossa ovalis - Umbilical cord tied Umbilical vessels close  Ductus venosus fibrosis. >> Ductus venosus -> Ligamentum venosum.

Question 38

State the 3 changes in structure that occur between a foetal placenta and adult mammal in regards to circulatory system,

Answer 38

Ductus arteriosus -> Ligamentum arteriosum Foramen ovale -> Fossa ovalis Ductus venosus -> Ligamentum venosum.