Bio 5.2

Question 1

What is air

Answer 1

a mixture of gases

Question 2

Total pressure of a mixture of gases =?

Answer 2

= sum of the partial pressure of individual gases

Question 3

How does gas move

Answer 3

moves from areas of high pressure to areas of low pressure

Question 4

how is the volume and pressure of a gas related

Answer 4

inversely related

Question 5

wha determines the amount of gas that will dissolve in a liquid

Answer 5

a. partial pressure of the gass

b. soluility of the gas in the liquid

Question 6

what is the eqn for partial pressure of an atmospheric gas

Answer 6

= patm x % of the gas in atmosphere

Question 7

wht is boyle’s law and what does it describe

Answer 7

pressure-volume relationphips are described by it

P1V1=P2V2

Question 8

As volum increases

Answer 8

pressure decreases

Question 9

why is pressure-volume relationship important (alveolar pressure)

talk about alveolar pressure

Answer 9

it is critical for ventilation

During inspiration and expiration, the volume of the thoracic cavity changes
- this causes changes in the alveolar pressure
- changes in the alveolar pressure are the driving force for air flow

Question 10

How does the volume change in lungs

Answer 10

there are no muscles in the lung so they cant change volume on their own

the muscles are in the chest wall and will contract to change the thoracic volume

the lungs are passive elastic structures (like ballons)

Question 11

What does volume depend on:

Answer 11

1. the transpulmonary pressure - difference between alveolar presssure and intrapleural pressure
2. the degree of elasticity of the lungs

Question 12

what is the alveolar pressure

Answer 12

the pressure inside the lungs

Question 13

what is the pressure in the intraplueral fluid

Answer 13

the pressure outside the lungs

Question 14

How does air get in

Answer 14

oral cavity or nasal cavity

Question 15

what is ventilation

Answer 15

the exchange of air betweeen the atmosphere and lungs

Question 16

where and to what do the air need to be conditioned to before it reaches the lungs

Answer 16

Airways serve an importante role in conditioning the air

air needs to:

1. Warm air to 37 degrees celcius to maintain core body temp and protect alveoli
2. add water vapour to air to prevent drying of epithelia
3. filter out foreighn materials

Question 17

How does the airway condition the air ( Ck- form ECCF stuff and cila)

Answer 17

airways are lined with ciliated epithelia that secrete a watery saline solution
- cells move from Cl- form ECCF into the cell via the NKCC-Cl- transported to the lumen of airway via apical anion channels
- Na+ moves beweeen cells from ECF to lumen - gradient og NACL draws water towards the lumen creating the watery saline solution

Cilia are covered with mucus that is secreted by goblet cells
- mucus contains immune cells that kill invaders
- mucus is moved up to the pharynx (mucus escalator)
- transferred to the digestive tract where additional bacteria are destroyed.

Question 18

What are the 2 steps of the respiratory cycle and in which do muscles conract

Answer 18

inspiration (contract) and expiration (dont contract)

Question 19

Explain inspiration

Answer 19

activetransport

1. Somatic motor nuerons trigger contraction of diaphragm and inspiratory muscles
2. Thorax expands - thoracic volume is up
3. Alveolar and intrapleural pressure decreases
4. Lungs expand resulting in air flowing into lungs

Question 20

Explain expiration

Answer 20

1. Impulses from somatic motor neurons stop
2. Diaphragm and thoracic muscles relax which returns thorax to their original position - volume down (elastic recoil)
3. Alveolar and intrapleural pressure increases
4. Elasticc recoil of the lungs decreases lung volume - air flows out of the lungs

Question 21

when is expiration passsive and active

Answer 21

quiet breathing passive

active breathing- excercise or heavy breathing

Question 22

Where is intraplueral pressure normally and when does int arise from

Answer 22

is normally sub-atmospheric and arises during feotal development

Question 23

wha helps keep the lung expaneded and open

Answer 23

having lower pressure in the plueral fluid (outside the lung) than inside the lung (at rest)

Question 24

What happens if air gets into the plueral cavity

Answer 24

intraplueral pressure increases

Question 25

what happens if pressure difference is abolished what is it called and how could it be treated

Answer 25

the lung collapses, called pnuemothoraxm, and to treat apply suction to remove the air and seal the hole

Question 26

the work required to breathe depends on two main factors:

Answer 26

1. compliance (stretchability of the lungs
2. the resistance to air flow in the airway