Circulatory System

Question 1

What are Arteries?

Answer 1

Carry blood away from the heart
Carry blood with oxygen (red) with the exception of the pulmonary artery
Walls are thick, strong, and stretchy 
Composed of three layers
Carry blood at high pressure

Question 2

What are Arterioles?

Answer 2

Smaller arteries
Vasoconstriction and vasodilation take place
Help lower blood pressure

Question 3

What are Capillaries?

Answer 3

Smallest vessel in the body (single cell layer thick)
Branch through tissues
Site of fluid and gas exchange (oxygen, nutrients, carbon dioxide and wastes) between blood and tissue fluid by diffusion
Red blood cells must pass through single file
Fragile

Question 4

What are Venules?

Answer 4

Smaller veins where deoxygenated blood collects from capillaries

Question 5

What are Veins?

Answer 5

Carry blood towards the heart
Blood is deoxygenated (blue) with the exception of the pulmonary vein
Thin walled; carry blood under low pressure
Contains valves which open in one direction only
The walls of veins allow materials to diffuse in and out easily

Question 6

What is the heart?

Answer 6

Muscular organ, size of your fist

Surrounded by a fluid-filled membrane called the pericardium that reduces friction

Question 7

What are the chambers in the heart?

Answer 7

Each side has two hollow muscular chambers that are separated by a wall called a septum
Four chambers total
Two thin walled atria (receives blood)
Two thick ventricles (pumps blood out of the heart)

Question 8

What is pulmonary circulation?

Answer 8

Deoxygenated blood pumped from the right side of the heart to the lungs via the pulmonary arteries

Blood picks up oxygen (oxygenated) and travels back to the left side of the heart via the pulmonary veins

Question 9

What is systemic circulation?

Answer 9

Left side of the heart pumps blood to the entire body via the aorta (largest artery)
From the aorta blood is diverted to
- coronary arteries (heart tissue)
- upper and lower body arteries
- Hepatic/Portal System (digestive)
Two large veins called the superior and inferior veins cava return blood to the right side of the heart

Question 10

What are valves in the heart?

Answer 10

Allow blood to flow in one direction only
AV (atrioventricular) valve separates atria and ventricles
SV (semilunar) valve separates ventricles and arteries (pulmonary trunk and aorta)
Tiny chords anchor flaps of valves to ventricle walls

Question 11

What controls the pumping of the heart?

Answer 11

SA node (sinoatrial node) initiates the controls of the heartbeat but external stimulation can speed up or slow down the heart

The SA node is located at the top right side of the right atrium. Electrical impulses are delayed from the top to bottom of the heart

When the atria are contracting the ventricles need to be relaxed and vice versa

Question 12

What is the external regulation of the heart rate?

Answer 12

The SA node is regulated externally by the parasympathetic and sympathetic nerves which conduct electrical impulses

Question 13

What is the Cardiac Cycle?

Answer 13

The sequence of heart chamber contraction

Diastole: chamber relaxation
Systole: chamber contraction

Question 14

What causes the “Lubb-dubb” sound in the heart?

Answer 14

“Lubb” caused by closing of both the atrioventricular valves

“Dubb” caused by closing of both the semilunar valves

Question 15

What is blood pressure?

Answer 15

The force that blood exerts on the walls of blood vessels

Blood pressure is highest in the blood vessels closest to the heart (aorta) and lowest in the veins

Question 16

Blood pressure depends on what two factors?

Answer 16

The volume of blood pumped (cardiac output)

The resistance to blood flow caused by narrowing of the arterioles (vasoconstriction and vasodilation)

Question 17

What is Capillary Exchange?

Answer 17

Blood moves through the capillary very slowly which allows time for exchange of materials

CO2 and O2 move in and out of capillary by process of diffusion

Water moves out of arteriole and carries sugar, amino acids, wastes, hormones, vitamins

Question 18

What two forces control movement of fluid through the capillary wall?

Answer 18

Osmotic pressure

Blood pressure

Question 19

Describe osmotic pressure in the capillary exchange.

Answer 19

Moves water from tissue fluid into blood

Question 20

Describe blood pressure in the capillary exchange.

Answer 20

Moves water from blood into tissue fluid
Solutes diffuse according to their concentration gradient
Glucose and oxygen diffuse out of capillary
Wastes and CO2 diffuse into capillary

Question 21

What is the lymphatic system?

Answer 21

Lymphatic vessels capture excess fluids leaked from capillaries

Collect products of fat digestion from small intestine

Lymph nodes found mainly in neck, groin, and armpit

Question 22

The pulsing of blood through the arteries that caused the systolic values of blood pressure to be recorded is due to the action of what structures?

Answer 22

The ventricles

Question 23

The movement of blood from the legs towards the heart is achieved through the use of:

Answer 23

Valves and muscular contraction

Question 24

In which direction will water molecules move at the arteriolar end of the capillary bed?

Answer 24

It will move from the blood to the tissue fluid

Question 25

In which direction will water molecules move at the venous end of the capillary bed?

Answer 25

It will move from the tissue fluid into the blood

Question 26

What does the P represent on an electrocardiogram?

Answer 26

Atrium excitation begins

Atrium contract

Question 27

What does after the P represent on an electrocardiogram?

Answer 27

Impulse delayed at SA node

Ventricles fill

Question 28

What does the QR represent on an electrocardiogram?

Answer 28

Ventricular excitation
Bicuspid and tricuspid valves close
Lub sound is made

Question 29

What does the RS represent on an electrocardiogram?

Answer 29

Ventricular excitation complete

Question 30

What does the T represent on an electrocardiogram?

Answer 30

Ventricular relaxation

Semilunar valves close