Blood Vessels(Complete)

Question 1

What is the connection between body size and transport needs?

Answer 1

Unicellular animals like amoeba obtain their nutrients and oxygen from their environment by diffusion.
They dispose their wastes into the environment by diffusion.

Larger multicellular and more active animals like humans need a vascular or transport system to deliver nutrients and oxygen to tissue cells.
They remove their metabolic wastes by excretion.

Question 2

What is a closed circulatory system?

Answer 2

In a closed circulatory system, blood is confined to blood vessels and flows in one direction only.

Question 3

What are the advantages of a closed circulatory system?

Answer 3

Allows for faster distribution of nutrients like glucose so that the organism can be more active as it has a higher metabolic rate.

Allows for the controlled distribution of blood.
Example: During exercise, more oxygenated blood is delivered to the leg muscles for increased respiration.

Question 4

What are the components of a closed circulatory system?

Answer 4

The Heart.
Blood Vessels.
The Blood.

Question 5

What is an open circulatory system?

Answer 5

The heart pumps blood into open-ended blood vessels.

Blood returns to the heart through openings in the heart wall.

Question 6

What are the disadvantages of an open circulatory system?

Answer 6

These organisms are less active as both oxygenated and deoxygenated bloods mix.

Question 7

What are examples of animals with an open circulatory system?

Answer 7

Insects.
Snails.
Spiders.

Question 8

What is the sequence of blood vessels from the heart to the body and back to the heart?

Answer 8

Heart- Artery- Arterioles- Capillaries- Venules- Vein- Heart.

Question 9

What are the key features of the arteries?

Answer 9

Carry blood away from the heart.
Thicker muscular elastic walls.
No valves as they carry blood under high pressure, except pulmonary artery and aorta.
Have a pulse.
Carry oxygenated blood, except the pulmonary artery.
Smaller lumen.

Question 10

What are the key features of the veins?

Answer 10

Carry blood towards the heart.
Thinner muscular elastic walls.
Have valves to prevent back flow of blood as pressure is low.
Veins carry blood against the force of gravity back to the heart.
No pulse.
Carry deoxygenated blood, expect the pulmonary vein.
Larger lumen.

Question 11

What is an arteriole?

Answer 11

They are the smallest arteries which branch to form capillaries.

Question 12

What is the role of the arteriole?

Answer 12

To regulate blood flow and pressure.

Question 13

What is a venule?

Answer 13

They are small veins that are formed when capillaries join together.

Question 14

What is the role of the venule?

Answer 14

To drain blood from capillaries into veins for return to the heart.

Question 15

What is the structure and function of collagen?

Answer 15

Structure- tough inelastic protein.

Function- reinforces the vessel wall by preventing over expansion.

Question 16

What is the structure and function of muscle tissue?

Answer 16

Structure- involuntary, contains smooth muscle which contracts slowly and is slow to tire.
Function- Can change the diameter of the vessel so it can alter blood pressure and volume of the blood.

Question 17

What is the function of the elastic tissue?

Answer 17

Allows for recoil allowing the vessel to return to its original size.

Question 18

What is the function of the endothelium?

Answer 18

Has a smooth low friction surface which eases blood flow through the vessel.

Question 19

What is the function of the lumen?

Answer 19

Central blood filled layer.

Question 20

Briefly describe how blood is moved through veins.

Answer 20

Valves in veins prevent back flow- this ensures that blood flows towards the heart.
Skeletal muscle contract and compress the thin walled veins to keep blood moving forward.

Question 21

Name the blood vessels that connect the arterial and venous systems.

Answer 21

The capillaries.

Question 22

What is a capillary?

Answer 22

Capillaries are thin walled, highly branched permeable blood vessels.

Question 23

Describe the structure of the capillary.

Answer 23

The walls are one cell thick and permeable.
They have no valve or pulse.
The lumen is very narrow.

Question 24

What are the functions of the capillaries?

Answer 24

They allow for the exchange of materials between blood and tissue cells as the walls are permeable.
They carry blood from the arteries to the veins- they carry both oxygenated and deoxygenated blood.

Question 25

What are the adaptations of the capillaries and their advantages?

Answer 25

The walls are one cell thick- There is a shorter diffusion distance for exchange.
They provide a large surface area- Allow faster exchange by diffusion.
They have a slow blood flow- Allow more time for exchange.