Structure of human lungs and ventilation system

Question 1

What are all the parts of the human lung and ventilation system?

Answer 1

• trachea
• bronchus
• intercostal muscles in ribs
• lungs
• pleural membranes
• alveoli
• bronchiole
• diaphragm

Question 2

What is the function of the trachea?

Answer 2

• tube like structure that carries air from mouth to lungs

Question 3

What is the function of the bronchus?

Answer 3

• trachea splits into two as it enters the lungs
• allows air to travel to left and right lung

Question 4

What similarities do the trachea and bronchus both have?

Answer 4

• thick walls lined with smooth muscle tissue
• supported by walls of cartilage, this holds airways open
• lined with epithelium tissue consisting of ciliated epithelium cells moving in a synchronised pattern to waft mucus up and out of airways
• and goblet cells to secrete mucus

Question 5

What is the function of the bronchioles?

Answer 5

• bronchi further divide into smaller branches called bronchioles
• lined with ciliated epithelial cells
• walls contain smooth muscle
• these supply alveoli with air

Question 6

What is the function of the alveoli?

Answer 6

• small air sacks at end of bronchioles
• gases pass both ways across alveoli to allow gas exchange
• has one layer of squamous epithelial cells
• giving a short diffusion pathway
• contains elastin in walls to allow stretch and recoil

Question 7

What is the function of the intercostal muscles?

Answer 7

• muscle groups situated inbetween ribs that create and move chest wall
  ext = forced and quiet inhalation + raise ribs and expand chest cavity
  int = forced exhalation

Question 8

What is the function of the diaphragm?

Answer 8

• dome shaped muscular partition between thorax and abdomen
• contraction increases volume of thorax + inflates lungs

Question 9

What is the function of the pleural membrane?

Answer 9

• membrane with one side lining body cavity wall and other lining lungs
• secretes serous fluid that reduces friction + enables membranes to slide over eachother
• prevents lungs from sticking to body cavity wall (slippery)

Question 10

How does the structure of lungs and alveoli ensure effective and efficient gas exchange?

Answer 10

• large SA = lots of alveoli, more space for gas molecules to pass thru
• short diffusion pathway = walls are made of one cell thick squamous epithelial cells, small distance
• capillary network = each alvelous is close to a one cell thick capillary to give short diffusion pathway + inc conc
• diffusion gradients = oxygen diffuses from high to low conc in alveoli down a conc gradient + maintained by ventilation
• moisture = layer of moisture lines alveoli, gases can only diffuse across membrane if dissolved, moisture allows oxygen to dissolve to diffuse thru into blood in capillaries
• surfactant = chemical produced by lungs to stop alveoli collapsing by reducing surface tension of water