Cardiovascular system

Question 1

Cardiovascular System

Answer 1

Consists of the heart and blood vessels and is designed to transport blood throughout the body. It takes about 1 minute for a drop of blood to travel through the right side of the heart, lungs, left side of the heart, systemic circulation, and completing its circuit by returning to the right side of the heart.

The cardiovascular system is vital in maintaining homeostasis within the body. In an average lifetime of 65-70 years, the human heart will beat approximately 2.5 billion times (about 100,000 times each day).

Question 2

Function: Pumping action

Answer 2

pumps blood to body and lungs, receives blood from body and lungs, and influences blood pressure.

Question 3

Function: Transportation

Answer 3

provides channels through which blood and lymph travel and provides areas (capillaries) where transfer of gases, nutrients, fluids, electrolytes, and wastes can occur. The term perfusion refers to the delivery of blood to a capillary bed.

Question 4

Heart

Answer 4

The heart is a strong, muscular double pump (one side pumps blood to the lungs, the other side pumps blood systemically) approximately the size of a clenched fist. It lies in the thoracic cavity in the mediastinum (mass of tissues and organs behind the sternum, between the lungs, and in front of the vertebrae column, between the second and sixth ribs). The heart, shaped like an irregular and slightly flattened cone. The inferior point is the apex, formed by the tip of the ventricle. The heart has three layers:

Question 5

Endocardium (inner heart

Answer 5

membrane lining the heart’s interior wall. Made up of endothelial tissue, small blood vessels, and some smooth muscles.

Question 6

Myocardium

Answer 6

thick, strong muscles compose the middle and thickest layer. Cardiac muscle is unique as it is lightly striated and involuntary, only found in the heart.

Question 7

Epicardium

Answer 7

The thin, outer layer of the cardiac wall (called the visceral layer of the serious pericardium). Composed of squamous epithelial cells over connective tissue.

Question 8

Pericardium

Answer 8

not considered a layer of the heart. The pericardium is a sac that surrounds and protects the heart. It functions by providing lubricant for the heart to reduce friction between the heart and the pericardium and anchoring the heart in the mediastinum and preventing the heart from overfilling.

Question 9

Heart chambers and valve

Answer 9

Chambers
Atria
Ventricles
Atrioventricular Valves 
Bicuspid
Tricuspid
Overflow valves

Question 10

Chamber: Atria

Answer 10

two upper chambers known as the right and left atria (singular: atrium). These are thin-walled, low-pressure chambers and receive blood. The muscles in the atria are thinner than either ventricles.

Question 11

Chamber: Ventricles

Answer 11

high-pressure chambers, they pump blood out of the heart. The left ventricle must contract with sufficient force to send blood to the entire body; therefore, its muscle walls are the thickest. Right ventricle needs only to pump blood to the low-pressure lungs; therefore, it is a thinner-walled chamber.

Question 12

Valves

Answer 12

as each heart chamber contracts, it pushes blood either into a ventricle or out the heart to the lungs or body. Cardiac valves are one-way tissue flaps that open and close in response to pressure changes within the chambers. These valves allow blood to flow in one direction only, preventing backflow.

Question 13

Atrioventricular Valves

Answer 13

atrioventricular (AV) valves lie between the atria and ventricles. The valve between the right atrium and right ventricle is the tricuspid valve, formed of three flaps (cusps) of tissues. The valve between the left atrium and left ventricle is the mitral or bicuspid valve, formed of only two flaps of tissue. Blood flows from the atria to the ventricles through open AV valves when the ventricular pressure is lower than atrial pressure. Contracting ventricles create increased pressure, causing AV valves to close.

Question 14

Overflow valves

Answer 14

crescent shaped (half-moon) cusps form the semilunar valves. The pulmonary semilunar valve (Pulmonic Valve) separates the right ventricle from the pulmonary artery. The aortic (semilunar) valve separates the left ventricle from the aorta. The semilunar valves open when ventricles contract, as the ventricles relax, blood flows backward toward the ventricles. Blood fills the semilunar cusps, which close the valves, preventing backflow.

Question 15

Blood Flow Route Of The Heart

Answer 15

the right atrium receives venous (deoxygenated) blood from the body via superior and inferior vena cavae.

Blood then passes through the tricuspid valve to the right ventricle, and moves through the pulmonic valve during ventricular contraction to enter the pulmonary artery, and then the lungs, where it exchanges carbon dioxide for oxygen.

From the lungs, blood (oxygenated) returns from the lungs via pulmonary veins to the left atrium, travels through the bicuspid valve to the left ventricle.

During ventricular contraction, the blood from the left ventricle exits through the aortic semilunar valve into the aorta and onto systemic circulation.

Question 16

Blood vessels of the heart

Answer 16

Coronary Vessels 
Arteries
Arterioles
Capillaries
Veins

Question 17

Cardiac Conduction

Answer 17

Cardiac Conduction – bundles of special tissue in the heart called sinoatrial (SA) and atrioventricular (AV) nodes transmit and coordinate electrical impulses to stimulate the heart to be able to pump blood. They share three characteristics:

Question 18

Automaticity

Answer 18

cells contract automatically and continuously without neural input – they can independently generate electrical pulse.

Question 19

Conductivity

Answer 19

each cell passes the signal on the next cell.

Question 20

Contractility

Answer 20

the cells have the ability to shorten fibers in the heart to pump blood in response to an impulse/signal.

Question 21

Components of the blood (PARTS)

Answer 21

Plasma

Red blood cells

White blood cells

Platelets

Question 22

Components of blood

Answer 22

blood is a vascular fluid. Blood is responsible for transportation of oxygen, carbon dioxide, nutrients, heat, waste products, disease fighting substances, and hormones to and from cells. It is also helps regulate pH, body temperature, and cellular water content and contributes to protection from blood loss and foreign body invasion.

Question 23

Plasma

Answer 23

the fluid portion of circulating blood, constitutes majority of the blood volume. Plasma is 90% water and the remaining 10% consists primarily of plasma proteins, salts (electrolytes), nutrients, nitrogenous waste products, gases, hormones, and enzymes.

Question 24

Red blood cells

Answer 24

called erythrocytes, are flattened, biconcave disks. RBC’s consists mainly of hemoglobin and cannot reproduce or synthesize protein. Hemoglobin binds to oxygen via iron present in the cell allowing transport of O2 throughout the body.

Question 25

White blood cells

Answer 25

also known as leukocytes. WBCs defend the body against disease organisms, toxins, irritants, and other foreign materials.

Question 26

Platelets

Answer 26

aka “thrombocytes” are the smallest formed elements in the blood and essential to blood clotting. They stimulate contraction of injured blood vessels and can form a hemostatic plug, to stop or slow bleeding by clumping many platelets together. They also combine with plasma to speed blood coagulation. Platelets are not whole cells, but fragments of larger cells.