SB8c The circulatory system

Question 1

What is the name given to a group of cells working together?

Answer 1

a Tissue

Question 2

What is the name given to the form different tissues make?

Answer 2

organs

Question 3

What is the name given to a group of organs working together?

Answer 3

organ system

Question 3

What are the components in the circulatory system?

Answer 3

The circulatory system consists of three major components:
 Heart
 Blood vessels
o Arteries
o Veins
o Capillaries
 Blood

Question 4

State the purpose of arteries and how they are adapted for their perpose.

Answer 4

Arteries carry blood away from the heart.

They carry mostly blood rich in oxygen (oxygenated).

They have thick, elastic walls to withstand the high pressure of the blood being pumped by the heart and a small/narrow lumen

Question 5

State the purpose of veins and how they are adapted for their purpose.

Answer 5

Veins carry blood to the heart.

They carry mostly blood low in oxygen (deoxygenated).

They have thin walls and wide lumen.

They contain valves to prevent backflow of blood.

Question 6

What are Valves?

Answer 6

Valves are flaps found in veins that ensure blood flows in only one
direction. There is no backflow of blood.

Question 7

State the purpose of cappilaries and how they are adapted for their purpose.

Answer 7

Capillaries are a fine network of blood vessels.

It is where gas exchange in cells and tissues takes place.

They are made of one-cell thick walls, which facilitates diffusion.

Question 8

What is blood made up of?

Answer 8

 Blood is made up of:
o Plasma
o Red blood cells
o White blood cells
o Platelets

Question 9

What precentage of blood is plasma and what colour.

Answer 9

 Plasma makes up 55% of blood
and is a yellow liquid.

Question 10

What is plasma made of?

Answer 10

 Plasma is mainly water with
dissolved substances such as
carbon dioxide, glucose,
hormones and antibodies.

Question 11

What does plasma do?

Answer 11

 It is responsible for transporting
these substances around the
body

Question 12

How are Red Blood Cells adapted for their perpose?

Answer 12

 Biconcave shape – increases surface area to volume ratio so oxygen diffusion happens faster.

 No nucleus – increases the amount of haemoglobin in the cell.
o More oxygen can be transported around the body by a single RBC.

 Thin membrane – short distance for diffusion.

 Flexible– so it can pass through capillaries

Question 13

What are platelets?

Answer 13

Platelets are tiny fragments of cells,
that also do not have nuclei

Question 14

What is the purpose of platelets?

Answer 14

They are responsible for blood clotting.
o An insoluble protein called fibrin is
released that causes cells to clump
up and stop the bleeding.

Question 15

When clots form there are two major
advantages. State them.

Answer 15

1. The blood flow stops so there is no
   blood loss.
2. The clot stops microorganisms
   from entering the body.

Question 16

What are the two types of White Blood Cells?

Answer 16

1. Lymphocytes that make antibodies (proteins that bind on the antigens of pathogens) and memory cells.
2. Phagocytes that engulf and digest pathogens.