The Circulatory System - A-Level Biology Aqa

Front 1

What is the circulatory system made up of?

Back 1

• The Heart

• Blood Vessels

Front 2

What materials are transported in the blood, around the body?

Back 2

• Respiratory gases

• Products of digestion

• Metabolic waste

• Hormones

Front 3

Describe the two circuits in the circulatory system.

Back 3

• Blood from the heart to the lungs, and back to the heart again.

• Blood from the heart to the rest of the body.

Front 4

Name 4 types of blood vessels

Back 4

• Arteries

• Arterioles

• Veins

• Capillaries

Front 5

How do arteries carry blood?

(Direction)

Back 5

Arteries carry blood away from the heart to the rest of the body.

Front 6

Explain how arteries are adapted to maintaining a high pressure when carrying blood.

Back 6

• Their walls are thick and muscular.

• Their walls contain elastic tissue => stretch and recoil as the heart beats.

• The inner lining (endothelium) is folded, allowing the artery to stretch.

Front 7

Arteries are divided into smaller vessels of what?

Back 7

Arterioles

Front 8

To where is blood directed to and from where?

Back 8

Blood is directed to different areas of demand in the body by muscles inside the arterioles.

Front 9

How do muscles in arterioles control blood flow?

Back 9

• The muscles contract => stop blood flow

• The muscles relax => allow blood flow

Front 10

How do veins carry blood?

Back 10

They carry blood back to the heart under a low pressure.

Front 11

How do veins carry blood?

Back 11

They carry blood back to the heart under a low pressure.

Front 12

Describe some characteristics of veins.

Back 12

• They have a wider lumen than arteries.

• They have very little elastic and muscle tissue.

Front 13

How is backwards flow of blood prevented in veins?

Back 13

Veins contain valves that stops the blood flowing backwards.

Front 14

Fill in the blank:

Blood flow through the veins is helped by ___________ of the ____ _______ surrounding them.

Back 14

Blood flow through the veins is helped by contractions of the body muscle surrounding them.

Front 15

Fill in the blanks:

All arteries carry __________ blood except for the _________ _______, which carry ____________ blood from the _____ to the _____.

Back 15

All arteries carry oxygenated blood except for the pulmonary arteries, which carry deoxygenated blood from the heart to the lungs.

Front 16

Fill in the blanks:

All veins carry ____________ blood except for the _________ _____, which carry __________ blood from the _____ to the _____.

Back 16

All veins carry deoxygenated blood except for the pulmonary veins, which carry oxygenated blood from the lungs to the heart.

Front 17

What do arterioles branch into?

Back 17

Arterioles branch into capillaries.

Front 18

Remember

Back 18

Substances, for example glucose and oxygen, are exchanged between cells and capillaries therefore capillaries are adapted for efficient diffusion.

Front 19

How are capillaries adapted for efficient diffusion?

Explain your answers.

Back 19

• They are always found near cells in exchange tissue (e.g. alveoli). This means there is a short diffusion pathway.

• Walls = 1 cell thick therefore diffusion pathway is shortened.

• There are a large number of capillaries, increasing the surface area for exchange.

Front 20

What is the name given to a network of capillaries in tissue?

Back 20

Capillary beds

Front 21

What do arterioles branch into?

Back 21

Arterioles branch into capillaries.

Front 22

Remember

Back 22

Substances, for example glucose and oxygen, are exchanged between cells and capillaries therefore capillaries are adapted for efficient diffusion.

Front 23

How are capillaries adapted for efficient diffusion?

Explain your answers.

Back 23

• They are always found near cells in exchange tissue (e.g. alveoli). This means there is a short diffusion pathway.

• Walls = 1 cell thick therefore diffusion pathway is shortened.

• There are a large number of capillaries, increasing the surface area for exchange.

Front 24

What is the name given to a network of capillaries in tissue?

Back 24

Capillary beds

Front 25

Where is tissue fluid formed?

Back 25

Tissue fluid is formed in the blood.

Front 26

What is tissue fluid?

Back 26

Tissue fluid is the fluid that surrounds cells in tissues.

Front 27

What is tissue fluid?

Back 27

Tissue fluid is the fluid that surrounds cells in tissues.

Front 28

What is tissue fluid made from?

Back 28

Tissue fluid is made from small molecules that leave the blood plasma.

Front 29

What is tissue fluid?

Back 29

Tissue fluid is the fluid that surrounds cells in tissues.

Front 30

What is tissue fluid made from?

Back 30

Tissue fluid is made from small molecules that leave the blood plasma.

Front 31

Give three examples of the small molecules that leave the blood plasma.

Back 31

• Oxygen

• Water

• Nutrients

Front 32

Why doesn't tissue fluid contain red blood cells or big proteins?

Back 32

Because these molecules are too large to be pushed through the capillary walls.

Front 33

Fill in the blanks:

Cells take in ______ and _________ from the tissue fluid and release _________ _____ into it.

Back 33

Cells take in oxygen and nutrients from tissue fluid and release metabolic waste into it.

Front 34

Fill in the blanks:

Cells take in ______ and _________ from the tissue fluid and release _________ _____ into it.

Back 34

Cells take in oxygen and nutrients from tissue fluid and release metabolic waste into it.

Front 35

How do substances move out of the capillaries into tissue fluid?

Back 35

They move out of the capillaries onto the tissue fluid via pressure filtration.

Front 36

Describe how tissue fluid is formed.

Back 36

• Hydrostatic pressure in capillaries is greater than hydrostatic pressure in tissue fluid.

• Difference results in overall outward pressure to force fluid out of the capillaries, into the spaces around cell.

Front 37

Describe how tissue fluid is formed.

Back 37

• Hydrostatic pressure in capillaries is greater than hydrostatic pressure in tissue fluid.

• Difference results in overall outward pressure to force fluid out of the capillaries, into the spaces around cell.

Front 38

How is water from the tissue fluid returned to the capillaries?

Back 38

• Fluid leaving reduces hydrostatic pressure in the capillaries.

• This means hydrostatic pressure at venule end of the capillary bed is much lower.

• The fluid loss (and increased concentration of plasma proteins) results in water potential being higher in tissue fluid than at the venule end of the capillary bed. Causing water to enter the capillaries (at the venule end) via osmosis.

Front 39

To where is excess tissue fluid drained to?

Back 39

Excess tissue fluid is drained into the lymphatic system.