The Circulatory System

Question 1

Describe the major components of the circulatory system and their main functions.

Answer 1

Blood: transport medium. dissolved or suspended materials (e.g. O2 CO2) are carried over long distances in the body.

The heart: pump that generates the cardiac output and pressure gradient needed for blood flow to organs and tissues.

blood vessels: a complex network of conduits or portals. blood is carried and distributed from the heart to all parts of the body and back to the heart

Question 2

describe the composition of blood and the main functions of its soluted and cellular constituents.

Answer 2

consists of blood cells (formed or cellular elements) suspended in liquid plasma.

3 main cellular types:
red blood cells: erythrocytes, contains haemoglobin and transport O2 to cells.

leukocytes (white blood cells): main body’s immune system. transported in the blood to sites of injury or disease-causing microorganisms.

platelets (thrombocytes): hemostasis, arrest of bleedings from the injured blood vessels.

Question 3

describe the location and the gross anatomy of the heart

Answer 3

hollow muscular organs, the size of a clenched fist.
located in the mediastinum, a section of the thoracic activity, the midline between the sternum (breastbone) and the vertebrae (backbone).
surrounded by a double-layered membrane, the pericardium.
consists of two upper chambers (left and right atrium). two lower chambers ( left and right ventricle). 4 valves, tricuspid, pulmonary, mitral, aortic valve.

Question 4

Aorta

Answer 4

accepts output of the left ventricle; first vessel of the
systemic circulation; sustains highest systolic pressure ~140 mmHg

Question 5

Pulmonary artery

Answer 5

accepts output of the right ventricle; first vessel
of the pulmonary circulation; sustains peak pressure ~25 mmHg

Question 6

Superior vena cava / inferior vena cava

Answer 6

largest vessels returning
deoxygenated blood to heart (right atrium) from systemic
circulation

Question 7

Pulmonary veins

Answer 7

largest vessels returning oxygenated blood to
heart (left atrium) from pulmonary circulation

Question 8

Coronary arteries & veins

Answer 8

supply blood to cardiac muscle tissue;
branch off from the aorta immediately above aortic valve; veins
drain blood into right atrium

Question 9

arteries

Answer 9

carry blood away from the heart to the tissues.

Question 10

arterioles

Answer 10

smaller branches of arteries within organs

Question 11

capillaries

Answer 11

smaller branches of arterioles within organs facilitate the exchange between blood and surrounding cells.

Question 12

venules

Answer 12

formed when capillaries rejoin, return blood to heart

Question 13

veins

Answer 13

formed when venules rejoin, return blood to the heart.