The cardiovascular system

Question 1

The heart

Answer 1

• An organ that is responsible for pumping blood throughout the body
• Cone shaped, 10 cm long, weighs about 310 g in men and 225g in women

Question 2

Anatomy of the heart

Answer 2

• The heart is located in the thoracic cavity in the mediastinum between the lungs.
• It lies obliquely and a little more (about two thirds) of the heart is located to the left than the right.
• Its base, the broad superior portion attaches large vessels and
  extends to the level of the 2nd rib

Question 3

Organs associated with the heart

Answer 3

• Inferiorly – Apex rests on the central tendon of the diaphragm
• Superiorly – Great blood vessels e.g. aorta, superior vena cava, pulmonary artery and veins
• Posteriorly – Oesophagus, trachea, Lt and Rt bronchus, descending aorta, inferior vena cava and thoracic vertebrae
• Laterally – Lungs
• Anteriorly – Sternum, ribs and intercostal muscles

Question 4

Structure of the heart

Answer 4

The heart wall is made of 3 parts,
1. pericardium- outer part
2. myocardium- middle part
3. Endocardium- inner part

Question 5

Pericardium

Answer 5

• Made up of 2 serous membranes
• Outer membrane- parietal pericardium,
• Inner membrane- Visceral pericardium
• Between the 2 layers is a space called pericardial space filled with serous fluid

Question 6

Function of parietal pericardium

Answer 6

preventing over distension of the heart

Question 7

Myocardium

Answer 7

• Middle layer and comprised of most
  cardiac muscle.
• It is striated and resembles the skeletal
  muscle fiber.
• Not under voluntary muscle control

Question 8

Endocardium

Answer 8

• Consists of flattened epithelial cells lining
  the myocardium and cardiac valves.
• Allows smooth flow of blood inside the heart.

Question 9

• The heart pumps blood through 2 systems of blood vessels namely

Answer 9

a. The pulmonary circulation
b. The systemic circulation

Question 10

a. The pulmonary circulation

Answer 10

Part of the circulatory system that carries deoxygenated blood to the lungs for oxygenation and then back to the heart

Question 11

Systemic circulation

Answer 11

Systemic circulation is the part of the circulatory system that carries oxygenated blood from the heart to the body’s tissues and returns deoxygenated blood back to the heart

Question 12

Process of systemic circulation

Answer 12

1.Oxygenated blood is pumped from the left ventricle into the aorta.
2.The aorta branches into smaller arteries, carrying blood to the body’s tissues.
3. In the capillaries, oxygen and nutrients are exchanged for carbon dioxide and waste products.
4. Deoxygenated blood is collected by venules and then veins.
5. The inferior and superior vena cava carry the deoxygenated blood back to the right atrium of the heart.

Question 13

The process of pulmonary circulation

Answer 13

1. Deoxygenated blood is pumped from the right ventricle of the heart into the pulmonary artery.
2. The pulmonary artery carries this blood to the lungs.
3. In the lungs, the blood releases carbon dioxide and absorbs oxygen.
4. The oxygenated blood is then transported back to the heart through the pulmonary veins.
5. The left atrium receives the oxygenated blood.

Question 14

Structure of an artery and a vein

Answer 14

The walls of arteries and veins are composed of 3 layers
or tunics namely
a. Tunica externa or adventitia
b. Tunica media
c. Tunica interna or intima

Question 15

Tunica externa or adventitia

Answer 15

Outermost layer of loose connective (fibrous) tissue

Question 16

Tunica media

Answer 16

middle layer of smooth muscle and
elastic tissue

Question 17

Tunica interna or intima

Answer 17

inner lining of squamous epithelium called endothelium.

Question 18

blood circulation through the heart

Answer 18

• Superior Vena Cava: Carries deoxygenated blood from the
  upper parts of the body to the heart.
• Inferior Vena Cava: Carries deoxygenated blood from the
  lower parts of the body to the heart.
• Pulmonary Arteries: They carry blood from the heart to
  the lungs to be oxygenated.
• Pulmonary Veins: They carry oxygenated blood from the
  lungs back to the heart.
• Aorta: It is the largest artery and carries oxygenated blood
  from the heart to the rest of the body.