Gas Exchange in Humans

Question 1

What is the Trachea?

Answer 1

A flexible airway that is supported by rings of cartilage which prevents it collapsing as the air pressure inside falls when breathing in

Question 2

What is the Bronchi?

Answer 2

Two divisions of the Trachea each leading to one lung

Question 3

What are the Bronchioles?

Answer 3

A series of branching subdivisions of the Bronchi whole walls are made up of muscle lined with epithelial cells

Question 4

What is the Alveoli?

Answer 4

Air sacs at the end of the Bronchioles

Question 5

What does Pleural Fluid?

Answer 5

This lubricates the lungs and helps the lungs adhere to the walls of the thoracic cavity by water cohesion which allows lungs to expand with the chest during inhalation

Question 6

What is function of the Cartilage and where is it found?

Answer 6

Found in the Trachea and Bronchus. Provides a strength to trachea and bronchus and holds the airway open. Prevents collapse of airway when air pressure falls

Question 7

What is function of the Surfactant and where is it found?

Answer 7

Found in the Coats surface of Lungs. The Phospholipid layer which maintains moisture but reduces surface tension to stop alveoli collapsing when air pressure falls

Question 8

What is function of the Smooth Muscle and where is it found?

Answer 8

Found in the lining of the Trachea- Bronchioles. Can contract to constrict

Question 9

What is function of the Goblet cells and where is it found?

Answer 9

Found in the lining trachea- bronchioles. Secrete mucus which taps particles of dust and bacteria which are breathed into the lungs

Question 10

What is function of the Ciliated epithelial cells and where is it found?

Answer 10

Found in the lining Trachea- Bronchioles. Beat regularly to move mucus up the airways through the mouth to be removed. Helps keep the airways clear and prevent infections

Question 11

What is function of the Elastin and where is it found?

Answer 11

Found in the lining of all airways and alveoli. Allows lung tissue to stretch when breathing in and filling up the lungs, recoil when breathing out to help force air out of the lungs

Question 12

What is function of the Squamous epithelium and where is it found?

Answer 12

Found in the lining alveoli. Gives a short diffusion distance pathway for oxygen and carbon dioxide in the alveoli

Question 13

What are the adaptations of the lungs?

Answer 13

Alveolar epithelium and capillary endothelium are very thin, large number of alveoli and capillaries that surround the alveoli are very narrow

Question 14

Why is there a large of capillaries around alveolis?

Answer 14

The circulation constantly removes oxygenated blood to maintain steep concentration gradient

Question 15

Why is constant ventilation of air in and out of lungs needed?

Answer 15

Ensures concentration of oxygen in alveoli is higher and concentration of carbon dioxide is lower than blood and therefore maintains steep concentration gradient

Question 16

What happens during Inhalation?

Answer 16

Diaphragm contracts
External intercostal muscles contract pulling ribcage moves up and out
Increases the volume of the thoracic activity which reduces the air pressure
Air moves into the Trachea down the pressure gradient

Question 17

What happens during Exhalation?

Answer 17

Diaphragm relaxes
External intercostal muscles relax, ribcage moves in and down
Decreases volume of the thoracic cavity which increases the air pressure because there is less space
Air moves out of the trachea down the pressure gradient