Circulatory system

Question 1

What is plasma?

Answer 1

Plasma makes up 55% of blood, is mainly water, and dissolves substances like nutrients, gases, and wastes.

Question 2

What do leukocytes (WBCs) do?

Answer 2

They fight bacteria and disease and break down foreign bodies.

Question 3

What is the function of erythrocytes (RBCs)?

Answer 3

They transport oxygen, contain hemoglobin, and are produced in bone marrow.

Question 4

What are thrombocytes (platelets)?

Answer 4

Cell fragments that help clot blood.

Question 5

Are platelets classified as blood cells?

Answer 5

Yes, they are called thrombocytes, but they are cell fragments, not full cells.

Question 6

How does hemoglobin help oxygen transport?

Answer 6

It allows oxygen to move freely in the blood.

Question 7

Why don’t RBCs have a nucleus or mitochondria?

Answer 7

To make more room for hemoglobin.

Question 8

Why is the biconcave shape of RBCs important?

Answer 8

It increases the surface area for oxygen exchange and allows a larger volume of hemoglobin.

Question 9

What are the main functions of plasma?

Answer 9

Transporting blood cells, nutrients, waste, and maintaining blood pressure and volume.

Question 10

What are the functions of blood?

Answer 10

Transport oxygen, fight infections, remove waste, and clot blood.

Question 11

What are the three types of blood vessels?

Answer 11

Arteries, veins, and capillaries.

Question 12

Why are artery walls so thick?

Answer 12

They need to withstand high pressure from the heart’s pumping.

Question 13

Why don’t veins have thick walls?

Answer 13

They return blood to the heart and don’t deal with high pressure.

Question 14

What is the function of valves in veins?

Answer 14

To prevent backflow and ensure blood returns to the heart.

Question 15

Why are capillaries one cell thick?

Answer 15

To allow efficient gas exchange of oxygen and CO₂.

Question 16

What is vasoconstriction?

Answer 16

The narrowing of blood vessels, which increases pressure.

Question 17

What is vasodilation?

Answer 17

The widening of blood vessels, which decreases pressure.

Question 18

Where is the heart located?

Answer 18

In the chest (thoracic cavity), slightly tilted to the left.

Question 19

What is pericardium?

Answer 19

A covering that prevents the heart from overstretching.

Question 20

What are the four chambers of the heart?

Answer 20

Two atria (receive blood) and two ventricles (pump blood).

Question 21

What does the right side of the heart do?

Answer 21

Receives blood from the vena cava and pumps it to the lungs.

Question 22

What does the left side of the heart do?

Answer 22

Receives blood from the pulmonary veins and pumps it to the body via the aorta.

Question 23

What separates the left and right sides of the heart?

Answer 23

The septum.

Question 24

What are the atrioventricular (AV) valves?

Answer 24

Valves between the atria and ventricles that prevent backflow of blood.

Question 25

What are chordae tendineae?

Answer 25

Fibrous cords that support the AV valves.

Question 26

Where is the tricuspid valve located?

Answer 26

On the right side of the heart (three flaps).

Question 27

Where is the bicuspid (mitral) valve located?

Answer 27

On the left side of the heart (two flaps).

Question 28

What are semilunar valves?

Answer 28

Valves at the base of the aorta and pulmonary artery to prevent backflow.

Question 29

Where is the aortic semilunar valve?

Answer 29

At the base of the aorta.

Question 30

Where is the pulmonary semilunar valve?

Answer 30

At the base of the pulmonary artery.

Question 31

How is oxygen transported in the blood?

Answer 31

97% binds to hemoglobin (Oxyhemoglobin: O₂ + Hb → HbO₂), 3% dissolves in plasma.

Question 32

Why are RBCs well-suited for oxygen transport?

Answer 32

Contain hemoglobin, no nucleus (more space for hemoglobin), biconcave shape (larger surface area).

Question 33

Where does oxygen enter the blood?

Answer 33

At the alveoli in the lungs (high oxygen concentration).

Question 34

How does oxygen move through the heart?

Answer 34

1. Oxygenated blood enters the left atrium via pulmonary veins, 2. Pumped through the aorta to body tissues.

Question 35

Why does oxygen leave the blood at body tissues?

Answer 35

Body tissues have a lower oxygen concentration than the blood.

Question 36

How is CO₂ transported in the blood?

Answer 36

70% as bicarbonate ion, 22% binds to hemoglobin (Carbaminohemoglobin), 8% dissolves in plasma.

Question 37

Where is CO₂ picked up?

Answer 37

At body tissues (high CO₂ concentration).

Question 38

How does CO₂ move through the heart?

Answer 38

1. Travels to the right atrium via the vena cava, 2. Pumped out via the pulmonary artery to the lungs.

Question 39

Where does CO₂ exit the blood?

Answer 39

At the alveoli (low CO₂ concentration) to be exhaled.

Question 40

What are the functions of pericardium

Answer 40

Pericardium is the casing around the heart and its functions are to prevent the heart from overfilling, hold the heart in place and protects it from infections of inflamation.