Exchange and Mass Transport - Lungs

Question 2

What is the trachea?

Answer 2

a flexible tube that allows air to flow into the lungs from the mouth/nose

Question 3

What is the structure of the trachea?

Answer 3

flexible tube supported by rings of cartilage

the wall is made up of muscle and lined with epithelial and goblet cells

Question 4

What is the function of cartilaginous rings in the trachea?

Answer 4

they allow the trachea to stay open when inhalation causes the air pressure to decrease

Question 5

What are the functions of the epithelial and goblet cells in the trachea?

Answer 5

goblet cells produce mucus and epithelial cells waft the mucus up and out of the lungs

Question 6

What are the bronchi?

Answer 6

the 2 divisions of the trachea that go into each lung

Question 7

What are the structure of the bronchi?

Answer 7

same structure as the trachea

Question 8

What are the bronchioles?

Answer 8

heavily branched tubes that carries air to all parts of the lungs

Question 9

What is the structure of the bronchioles?

Answer 9

walls are made of muscle

heavily branched

Question 10

What is the function of the muscled walls in bronchioles?

Answer 10

the muscle allows the to regulate the flow of air into and out of the alveoli by contraction of the pipes

Question 11

What are alveoli?

Answer 11

minute air sacs that allow for the gas exchange between air and blood

Question 12

What is the structure of the alveoli?

Answer 12

100-300μm across

positioned at the end of the bronchioles

contains collagen and elastic fibres

Question 13

What is the function of the collagen and elastic fibres in alveoli?

Answer 13

to help the alveoli stretch and compress to pull air in and out

Question 14

What is the intercostal muscle?

Answer 14

the muscle between the ribs

Question 15

What is the purpose of the of the intercostal muscle?

Answer 15

to allow the ribs to contract and expand

Question 16

Why do mammals need lungs?

Answer 16

1. they are larger animals and so need to increase SA:V
2. increases efficiency of exchange

Question 17

Why are mammalian lungs inside the body?

Answer 17

air is not dense enough to support and hold open the delicate structures

the body would lose a lot of water and dry out

Question 18

What is inspiration?

Answer 18

the process of drawing air into the lungs

Question 19

When does inspiration occur?

Answer 19

when the air pressure is greater in the atmosphere than inside the lungs, causing air to be forced into the lungs

Question 20

What is expiration?

Answer 20

the process of forcing air out of the lungs

Question 21

When does expiration occur?

Answer 21

When the air pressure inside the lungs is greater than the atmosphere, causing air to be forced out of the lungs

Question 22

Which 3 muscles allow for pressure changes in the lungs?

Answer 22

Diaphragm

Internal intercostal muscles

External intercostal muscles

Question 23

What is the diaphragm?

Answer 23

a sheet of muscle that separates the thorax from the abdomen

Question 24

Contraction of which intercostal muscle leads to expiration?

Answer 24

internal intercostal muscles

Question 25

Contraction of which intercostal muscle leads to inspiration?

Answer 25

external intercostal muscles

Question 26

Describe the process of inspiration

Answer 26

1. external intercostal muscles contract, internal relax
2. ribs are pulled upwards and outwards, increasing volume of the thorax
3. diaphragm contracts, flattening it, increasing volume of the thorax
4. increased volume of thorax results in lower pressure in lungs
5. atmospheric pressure now greater than pulmonary pressure, forcing air into the lungs

Question 27

Describe the process of expiration

Answer 27

1. internal intercostal muscles contract, external relax
2. ribs move downwards and inwards, decreasing volume of thorax
3. diaphram relaxes and is pushed up by abdomen, decreasing volume of thorax
4. decreased volume of thorax increases pressure in lungs
5. as the pulmonary pressure > atmospheric pressure, air is forced out of the lungs

Question 28

What is the thorax?

Answer 28

the area where the lungs are

Question 29

What are some key adaptations of the capillaries near the alveoli?

Answer 29

red blood cells are slowed as they pass through narrow capillary walls - increases time for diffusion

red blood cells are flattened against capillary wall reducing diffusion pathway

massive shared surface area with alveoli

flow of blood maintains concentration gradient for exchange

Question 30

Why is it useful for breathing movements to keep the lungs ventilated?

Answer 30

the concentration gradients O₂ and CO₂ between alveoli and capillaries are maintained

Question 31

What is the order of pleural membranes and spales on the lungs?

Answer 31

Pleural membrane

Pleural spale

Pleural membrane

Lung