Anatomy

Question 1

What is the CVS?

Answer 1

Heart, blood vessels and lymphatics.

Question 2

Where is the CVS located?

Answer 2

Heart middle mediastinum, blood vessels everywhere, and lymphatic vessels everywhere except eyes and brain.

Question 3

What is the mediastinum?

Answer 3

Block of structures that sit between the 2 lungs and pleura. Structures include: thymus, heart, oesophagus, sympathetic chain etc.

Question 4

What is a portal system?

Answer 4

A system that begins and ends in capillaries without having gone through the heart: capillaries, portal vein and more capillaries.

Question 5

Define portosystemic shunt.

Answer 5

Blood from the portal system backing into the systemic system - eg. cirrhosis of the liver causes pressure to build up in the portal vein as blood can’t go through the liver, so it goes backwards.

Question 6

Describe the surface anatomy of the heart.

Answer 6

Lies in the middle mediastinum behind the sternum. Apex is in the 5th left intercostal space in the midclavicular line in the recument position. Heart between the sternopericardial ligaments.

Question 7

Which structure covers the heart?

Answer 7

Pericardium - 2 layers: fibrous pericardium on the outside and serous (visceral/parietal) on the inside.

Question 8

Describe the anatomical relations of the heart.

Answer 8

ANTERIORLY: sternum, costal cartilages 1-7, anterior edges of lungs and pleurae, and remnants of thymus gland. POSTERIORLY: oesophagus, descending aorta and thoracic vertebrae 5-8. LATERALLY: lungs and phrenic nerve. INFERIORLY: central tendon of diaphragm.

Question 9

Which structures lie at the front of the heart?

Answer 9

2/3 RV, part of RA and part of LV. 2/3 of heart lies to left of sternum, 1/3 lies to right.

Question 10

What are the 3 layers of the heart wall?

Answer 10

1) Epicardium: outermost; continuous with visceral layer of pericardium; connective tissue; main branches of coronary arteries. 2) Myocardium: thick middle layer of cardiac muscle; striated muscle lots of mitochondria; myocytes connected by lots of intercalated disks. 3) Endocardium: innermost layer; lines heart chambers and forms valves.

All epithelium is simple squamous.

Question 11

What are intercalated disks?

Answer 11

Junctions that connect myocytes. Desmosomes connect at horizontal interface to bind myocytes together. Gap junctions connect at vertical interface to transfer electrical impulses.

Question 12

Describe valve abnormalities.

Answer 12

Incompetence is widening, stenosis is narrowing and infection is endocarditis.

Question 13

How many cusps does each valve have?

Answer 13

Aortic and pulmonary have 3, tricuspid has 3 and bicuspid/mitral has 2.

Question 14

What is the function of SA and AV nodes?

Answer 14

Pacemakers.

Question 15

Describe the serous pericardium.

Answer 15

Visceral layer continuous with epicardium, parietal layer bound to fibrous pericardium. Secretes pericardial fluid which is lubricant.

Question 16

Which thoracic organs are not included in the mediastinum?

Answer 16

Lungs.

Question 17

Which structures are included in the superior mediastinum?

Answer 17

Thymus, brachiocephalic vein and SVC, branches of aortic arch, vagus nerve, phrenic nerve, trachea, oesophagus and thoracic duct.

Question 18

Which structures are included in the inferior mediastinum?

Answer 18

Oesophagus, vagus nerve, azygous nerve, sympathetic trunk, thoracic duct, descending aorta, sphlanchnic nerve and white and grey rami communicantes.