lungs

Question 1

how do lungs provide an efficient gas exchange surface

Answer 1

they have a short diffusion distance and large surface area

Question 2

what is the structure and function of the trachea

Answer 2

• shaped with rings of cartilage for support
• is a tube like structure that carries air from mouth to lungs

Question 3

what are bronchi

Answer 3

The trachea splits into two bronchi as it enters the lungs, which allows air to travel to the left and right lung (singular: Bronchus)

Question 4

what are bronchioles

Answer 4

The Bronchi further divide into smaller branches called bronchioles. These then supply the alveoli with air

Question 5

what is a diaphragm

Answer 5

curved band of muscles

Question 6

what are the 2 layers that the O2 needs to pass through to enter the bloodstream from alveoli

Answer 6

alveolar squamous epithelium and the endothelial wall of the capillary

Question 7

how is the alveolar squamous epithelium adapted to optimize diffusion

Answer 7

one cell thick layer with a very thin diffusion distance

Question 8

give the alveoli structure

Answer 8

• small sacs at the end of the bronchioles
• they have a large surface area
• have a dense capillary network pressed against it to maintain efficient diffusion rates

Question 9

how does the alveoli maintain a large conc gradient

Answer 9

The alveoli have a rich blood supply which circulates blood to maintain a large concentration gradient between the gases in the blood and in the alveoli.

Question 10

describe the mechanism of inhilation

Answer 10

· External intercostal muscles contract pulling rib cage UP & OUT

· Diaphragm contracts and pulls down

· Thoracic cavity volume increases

· Pressure in lungs LOWER than atmospheric pressure

· Air moves into lungs down a pressure gradient.

Question 11

how does the pressure inside the lungs change by

Answer 11

the changes in volume of lungs

Question 12

what is ventilation

Answer 12

the movement of air into and out of the lungs to supply oxygen to the body and remove carbon dioxide

Question 13

describe the mechanism for exhalation

Answer 13

· External intercostal muscles relax

· Diaphragm relaxes and moves up

· Thoracic cavity volume decreases

· Pressure in lungs GREATER than atmospheric pressure

· Air moves out of lungs down a pressure gradient

Question 14

what does the moist alveolar surface do

Answer 14

has moisture which helps dissolve the O2 gas

Question 15

describe the diffusion of O2 in the alveoli

Answer 15

As the blood reaches the capillaries surrounding the alveoli, oxygen diffuses into the blood across the squamous epithelial membrane and endothelial wall of the capillary, moving from higher O2 concentration to lower O2 concentration.

Question 16

describe the diffusion of CO2 in the alveoli

Answer 16

carbon dioxide moves from the blood into the alveoli as the concentration of CO2 in the blood from the pulmonary artery is greater than that in the inhaled air in the alveoli.

Question 17

how does the body ensure that the gases do not reach equilibrium at the alveolis

Answer 17

circulation of blood by the heart and the ventilation of air through breathing, maintains a concentration gradient

Question 18

what is Tidal volume

Answer 18

Natural breathing volume (at rest or at steady rate of exercise)

Question 19

what is Inspiratory/Expiratory reserve

Answer 19

Extra volume required for a deep breath.

Question 20

what is Residual Volume

Answer 20

Air that remains in lungs to prevent collapse of alveoli

Question 21

what is vital capacity

Answer 21

Maximum volume of air a person can expel from the lungs.