The Cardiovascular system

Question 1

What are the three main components of the human Cardiovascular system?

Answer 1

1. Heart
2. Blood Vessels
3. Blood

Question 2

Papillary muscle

Answer 2

Attaches to the base of the cordae tenineae to help pulling the atrioventricular valve closed.

Question 3

Name the layers of the heart wall.

Answer 3

Question 4

Septum

Answer 4

Divides the right and left sides of the heart.

Consists of mydocardium covered by endocardium.

Question 5

What is the overall structure of the cardiovascular system?

Answer 5

Closed, double circulatory system.

Question 6

Name main components of the blood.

Answer 6

Serum

Red Blood Cells

Question 7

What is the main role of red blood cells?

Erythrocytes

Answer 7

Essential in gas transport.

Found in huge number in the blood and contain the gas transport protein hemoglobin.

Mature cells do not have a nucleus.

Question 8

Atriventricular Valves

Answer 8

Vales in both the right and left of the heart that allow blood flow from the atrium into the ventricle.

Question 9

Which tissue makes up the largest part of the heart wall?

Answer 9

Muscle.

Question 10

What is the main role of white blood cells?

Leukocytes

Answer 10

Leukocytes fight infection.

They are larger than red blood cells and possess a nucleus.

Question 12

Pericardium

Answer 12

Outermost layer of the heart made up of two sacs.

Inner sac - continuous double layer of serous membrane

Outer sac - fibrous tissue that is inelastic and attached to the diaphram. Prevents overdistention of the heart.

Question 13

Systemic Circulation

Answer 13

Supply of oxygen and nutrients to the tissues of the body and the removal of waste materials from these tissues.

Question 14

Autorhymicity

Answer 14

The heart’s ability to generate its own electrical impulses.

Beats independently of nervous or hormonal control.

Question 15

Sinoatrial (SA) Node

Answer 15

A small mass of specialized cells that lie in the wall of the right atrium near the opening of the superior vena cava.

Sinoatrial cells generate regular impulses because they are electrically unstable.

These cells discharge regularly (depolarize) followed by almost immediate repolarization.

This happens 60-80 times a minute to generate the heartbeat.

Firing of the SA node triggers arterial contraction.

Known as the pacemaker of the heart.

Question 16

Capillaries

Answer 16

Found at the end of the smallest arterioles.

Walls consists of a single layer of endothelial cells sitting on a very thin basement membrane through which water and other small molecules can pass.

Blood cells and large molecules do not pass through capillary walls.

Capillary bed is the site of exchange of substances between the blood and the tissue fluid which bathes the cells.

Question 17

Platelets

Thrombocytes

Answer 17

Small fragments of cells which contain a variety of chemicals which stop bleeding and initiate blood clotting.

Live for about 5-9 days and are destroyed by the liver and spleen.

Question 18

Veins and venules

Answer 18

Return blood at low pressure to the heart.

• thinner walls than arteries as low pressure
• same three tissue layers as arteries & arterioles

Valves & Valve cusps prevent backflow of blood.

Question 19

Atrioventricular (AV) Node

Answer 19

Small mass of neromuscular tissue situated in the wall of the arterial septum near the atrioventricular valves.

Normally transmits the electrical signals from the atria to the ventricles.

Secondary pacemaker function and takes over this role if there is a problem with the SA node or with the transmission of impulses from the atria.

Slower rate 40-60 beats per minute.

Question 20

Describe blood flow around the heart starting with the vena cava.

Answer 20

Superior & Inferior vena cava –>

Right Atrium –>

Right ventricle –>

Right & Left Pulmonary Artery –>

Right & Left Lungs –>

Pulmonary Veins from Right & Left Lungs –>

Left Atrium –>

Left ventricle –>

Aorta out to the body

Question 21

Name the 5 main types of blood vessel.

Answer 21

1. Arteries
2. Arterioles
3. Veins
4. Venules
5. Capillaries

(found at the ends of the smalles arterioles)

Question 22

Valve cusps

Answer 22

Semilunar in shape with concavity toward the heart.

Formed by a fold of tunica intima and strengthened by connective tissue.

Question 23

Name the different parts of the heart.

Answer 23

Question 24

Name the 3 layers of Artery and Arteriole walls.

Answer 24

1. Tunica intima - lining of the squamous epithelium (called the endothelium)
2. Tunida Media - middle layer or smooth muscle and elastic tissue.
3. Tunica adventita - outer layer, fibrous tissue.

Question 25

Pulmonary Circulation

Answer 25

Carries blood to the lungs for the purposes of gas exchange.

Question 26

Endocardium

Answer 26

Innermost layer that lines the chambers and valves of the heart. Thin, smooth membrane which permits smooth blood flow in and out of the heart.

Consists of flatened epithelial cells and is continuous with the endothelium lining of the blood vessels.

Question 27

Chordae Tendineae

Answer 27

Prevent the atrioventricular valves from opening during ventricular contraction.

Extend from the inferior surface of the cusps and are tendinous cords.

Question 28

Name the functions of the blood.

Answer 28

1. Transport
2. Regulation
3. Protection
4. Coagulation

Question 29

The Myocardium.

Answer 29

Thick layer of the heart wall composed of specialised cardiac muscle found only in the heart.

• Not uner voluntary control
• Striated like skeletal mushle
• Each cell has a nucleus and one or more branches.
• Joints between cells are intercalated discs which are thicker striations.
• impulses spread through each cell & intercalated discs like a wave, no nerve cells required. These impulses cause contraction of heart.