The Circulatory System

Question 1

What are the components of the circulatory system?

Answer 1

• blood
• blood vessels
• heart

Question 2

What is the role of red blood cells?

Answer 2

To carry oxygen around the body

Question 3

What shape are red blood cells? Why?

Answer 3

• biconcave
• to provide a large surface area for diffusion of oxygen

Question 4

What are the two purposes of the circulatory system?

Answer 4

• transportation of substances
• protection against diseases

Question 5

Why do red blood cells have no nucleus?

Answer 5

Increases space (or volume) for haemoglobin and oxygen

Question 6

What are the main components of the blood? (4)

Answer 6

• red blood cells
• white blood cells (Lymphocytes and Phagocytes)
• platelets
• plasma

Question 7

What is the purpose of the two forms of white blood cell?

Answer 7

• Lymphocytes produce antibodies
• phagocytes engulf and digest microorganisms in phagocytosis

Question 8

What are the three types of blood vessels?

Answer 8

• Veins
• arteries
• capillaries

Question 9

In which direction does blood flow through each blood vessel?

Answer 9

• artery - away from the heart
• vein - to the heart
• capillary - from arteries to veins

Question 10

What is the thickness of the wall of each blood vessel?

Answer 10

• artery - thick
• vein - relatively thin
• capillary - one cell thick (smallest)

Question 11

What is the blood pressure in each blood vessel?

Answer 11

• artery - high
• vein - low
• capillary - low

Question 12

Which blood vessel always contains valves?

Which blood vessel is the only exception to this?

Answer 12

1. Veins
2. The aorta (artery)

Question 13

What is haemoglobin?

Answer 13

An iron rich substance which carries oxygen in red blood cells

Question 14

What do white blood cells do broadly speaking?

Answer 14

Protect against disease

Question 15

What is the broad purpose of platelets? (2)

Answer 15

• To aid blood clotting
• to form scabs

Question 16

How do platelets work?

Answer 16

• They convert the soluble protein fibrinogen to the insoluble fibrin
• this fibrin forms a mesh network that traps other blood components

Question 17

What is the purpose of plasma?

Answer 17

It is responsible for the transport of:
- blood cells
- absorbed food molecules
- carbon dioxide
- hormones
- urea
Etc.

Question 18

What is a lumen

Answer 18

The cavity (space) within a tubular structure

Question 19

What is the function of the pulmonary vein?

Answer 19

Carries oxygenated blood from the lungs to the heart

Question 20

What is the function of the aorta?

Answer 20

Carries oxygenated blood from the heart around the body

Question 21

What is the function of the vena cava?

Answer 21

Carries deoxygenated blood from the body back to the heart

Question 22

What is the function of the pulmonary artery?

Answer 22

Carries deoxygenated blood from the heart to the lungs

Question 23

What is the function of the hepatic artery?

Answer 23

Carries oxygen and glucose to the liver

Question 24

What is the function of the hepatic portal vein?

Answer 24

Carries digested food from the small intestine to the liver

Question 25

What is the function of the **hepatic vein**?

Answer 25

Carries **glucose and amino acids** from the *liver around the body* As well as **carbon dioxide** (from respiration) back *to the heart and lungs*

Question 26

What is the function of the **renal artery**?

Answer 26

Carries blood rich in **urea** to the *kidneys for excretion*

Question 27

What is the function of the **renal vein**?

Answer 27

Carries **purified blood** (low in urea) from the *kidney to the vena cava* As well as **carbon dioxide** (from respiration) back to the *heart and lungs*

Question 28

What is **unique** about the **human** and **mammal circulatory system**?

Answer 28

They are double circulatory systems

Question 29

What is meant by a ‘**double circulatory system**’?

Answer 29

A system of blood flow where: - blood enters the heart twice - during a single circulation

Question 30

What blood vessel does the **actual heart muscle** *receive blood* from?

Answer 30

The **coronary arteries** (which are extensions from the aorta)

Question 31

What **differences** are there between the **pulse rate** of a **fit person** and an **unfit person** during **exercise**? (**3**)

Answer 31

A **fitter person** will have: - a **lower** *resting heart rate* - a **lower maximum** heart rate - a **shorter recovery** time

Question 32

What are the **two main benefits** of regular exercise for the **heart**?

Answer 32

- it **strengthens** the **heart’s muscle** - it **increases cardiac output** (more blood/min)

Question 33

Why does *pulse rate* **increase** *during exercise*? (**3**)

Answer 33

- muscle *cells* require more **glucose and oxygen** - for **respiration** - to **produce energy** for movement of the muscles

Question 34

How does **increased cardiac output** influence the **movement of blood** to muscles? (**2**)

Answer 34

- increases **blood pressure** - causing **increased blood flow** to muscles

Question 35

What is the purpose of valves?

Answer 35

To prevent back flow of blood