human lung system & prevent water loss

Question 1

What is the definition of tidal volume

Answer 1

the volume of air in each breath

Question 2

What is the definition of ventilation rate?

Answer 2

the number of breaths per minute

Question 3

What is the definition of Forced expiratory volume?

Answer 3

maximum volume of air that can be breated out in 1 second

Question 4

What is the definition of forced vital capacity?

Answer 4

maximum volume of air possible to breath forcefully ut of the lungs after a really deep breath

Question 5

What is the definition of pulmonary ventilation rate?

Answer 5

Total volume of air moved into the lungs during one minute

Question 6

What is the equation of pulmonary ventilation rate?

Answer 6

tidal volume x ventilation rate

Question 7

What is Fix law?

Answer 7

surface area x difference in concentration gradient) / thickness of surface.

Question 8

What is vital capacity?

Answer 8

the maximum amount of air you can inspire and expire in one breath

Question 9

What is the definition of residual volume?

Answer 9

The amount of air that remains in a person’s lungs after maximum exhalation

Question 10

What is the definition of total lung capacity?

Answer 10

volume of air in the lungs after a maximal inhalation

Question 11

What is the definition of inspiratory reserve volume?

Answer 11

the amount of air a person can inhale forcefully after normal tidal volume inspiration

Question 12

What is the definition of expiratory reserve volume?

Answer 12

the amount of air a person can exhale forcefully after a normal exhalation.

Question 13

What is the equation for vital capacity?

Answer 13

tidal value + IRV + ERV

Question 14

What is the equation of total lung volume?

Answer 14

residual volume + vital capacity

Question 15

Describe and explain how the structure of the mammalian breathing system enables efficient uptake of oxygen into the blood ( 6 marks)

Answer 15

• alveoli provide a large surface area
• walls of alveoli thin to provide a short diffusion pathway
• walls of capillary thin/ close to alveoli provides a short diffusion pathway
• walls of capillaries alveoli have flattened cells
• cell membrane permeable to gases
• many blood capillaries to provide a large surface area
• Ventilation maintains a diffusion gradient
• wide trachea
• bronichioles allow efficient flow of air
• cartilage rings keeps airways open

Question 16

What are the adaptions of the leaf for gas exchange?

Answer 16

• many stomata and no cell is far from a stoma and therefore the diffusion pathway is short
• numerous interconnecting air spaces that occur throughout the mesophyll, so that gases can readily come in contact with mesophyll cells
• the large surface area of mesophyll cells for rapid diffusion.

Question 17

What are xerophytes?

Answer 17

plants that are adapted to environments with a very little water availability

Question 18

How are insects adapted to reduce water loss?

Answer 18

small surface area to volume ratio = minimize the area of which water is lost

waterproof coverings over their body surfaces = rigid out skeleton of chitin

spiracles = can be closed to reduce water loss

Question 19

How are xerophytes adapted for water loss?

Answer 19

• thick, waxy cuticle = slower diffusion due to the increase in the diffusion distance. Waxy = impermeable to water and waterproof
• rolling up of leave = traps layer of humid air , so the breeze cannot take lost water away. therefore this area becomes saturated with water vapor and so has a very high water potential. this means there is no diffusion gradient between the inside and outside of the lead, as the water molecules cannot go against the concentration gradient
• Hairy leaves = traps water vapor that diffuses out, wind can’t take it away (reduced air movement. Water potential gradient between the inside and the outside of the leaves is reduced and therefore less water is lost by evaporation
• Stomata in pits or grooves= Water vapour is trapped in sunken stomata = wind cant access it so water gradient decreases
• reduced SA:V of the leaves

Question 20

mechanism of gas exchange in the leaf

Answer 20

When the guard cells are turgid (full of water) the stoma remains open allowing air to enter the leaf

The air spaces within the spongy mesophyll layer allows carbon dioxide to rapidly diffuse into cells

The carbon dioxide is quickly used up in photosynthesis by cells containing chloroplasts - maintaining the concentration gradient

No active ventilation is required as the thinness of the plant tissues and the presence of stomata helps to create a short diffusion pathway