B3.1 Movement of molecules + gaseous exchange

Question 1

What is diffusion and osmosis caused by?

Answer 1

A difference in concentration between the inside and outside of the cell

Question 2

What do most soft drinks contain? (3 things)

Answer 2

Water, sugar and ions

Question 3

What do most sports drinks contain and why?

Answer 3

• Sugars: to replace sugar used in ENERGY RELEASE during activity
• Water and ions to replace the water and ions lost during SWEATING

Question 4

What happens if water and ions are not replaced?

Answer 4

The ion/water balance of the body is disturbed and cells do not work as efficiently

Question 5

What happens to cells undergoing active transport that is different to osmosis or diffusion?

Answer 5

They are absorbed against the concentration gradient

Question 6

How is the effectiveness of an exchange surface increased? (4 points)

Answer 6

• Thin for a short diffusion path
• Large surface area
• Efficient blood supply
• Well ventilated (animals; gaseous exchange)

Question 7

How does the size and complexity of an organism affect the difficulty of exchanging materials?

Answer 7

The larger/more complex the organism, the MORE DIFFICULT to exchange materials

Question 8

Give 2 examples of adaption in humans to increase the effectiveness of an exchange surface

Answer 8

• Lung surface area= increased by alveoli

- Small intestine surface area= increased by villi.

Question 9

What do villi do?

Answer 9

• Provide a LARGE SURFACE AREA with an extensive network of capillaries
• To ABSORBthe products of digestion by diffusion and active transport

Question 10

Where are the lungs?
What are they protected by?
What are they separated from the abdomen by?

Answer 10

• In the upper part of the body (thorax)
• Protected by ribcage
• Separated by the diaphragm.

Question 11

What does the breathing system do and why does it do it?

Answer 11

• It takes air into and out of the body
• So that oxygen from air can diffuse into blood
• So carbon dioxide can diffuse out of blood into the air

Question 12

What do the ribcage and diaphragm do to make air move INTO the lungs?

Answer 12

Intercostal muscles contract= ribcage moves out and up

Diaphragm= flatter (contracts) and increases volume of chest

Question 13

When you inhale, what happens to the pressure in the chest?

Answer 13

Increase in volume

LOWER PRESSURE

Question 14

What happens when you exhale? Key words: ribcage, diaphragm, volume

Answer 14

• Ribcage relaxes, down and in

- Diaphragm relaxes, upwards, volume decerases

Question 15

What is the movement of air into and out of the lungs known as?

Answer 15

Ventilation

Question 16

How is air DRAWN INTO the lungs in a negative pressure ventilator? (make 4 points)

Answer 16

• Airtight machine, neck down
• Vacuum around thorax
• Negative pressure
• Thorax expands, pressure decreases

Question 17

How is air FORCED OUT OF the lungs in a +/- pressure ventilator? (2 points to make, 4 marks)

Answer 17

• Ventilator stops (vacuum is released in negative)

- Elasticity of lungs, diaphragm and chest wall cause exhalation

Question 18

How is air DRAWN INTO the lungs in a positive pressure ventilator? (make 4 points)

Answer 18

• Tube inserted into trachea
• Ventilator pumps air in
• Lungs inflate

Question 19

Give one advantage for both a negative pressure ventilator and a positive pressure ventilator

Answer 19

+ve Useful during OPERATIONS where surgeons need access to the body
-ve Effective at treating POLIO patients over the years

Question 20

What are two disadvantages of a negative pressure ventilator?

Answer 20

• Patient is CONFINED to the machine

- Vacuum can affect abdomen–> pooling of blood

Question 21

What is one disadvantage of a positive pressure ventilator?

Answer 21

Long-term ventilation require the tube to be SURGICALLY INSERTED through neck into trachea

Question 22

What is the difference between a modern ventilator and an iron lung?

Answer 22

• Iron lung= outside pressure forces air in

- Modern ventilator= air is forced mechanically into lungs