Topic 2: Genes and health

Definition of epithelial

The specialised layer of cells that forms the covering or lining of a body surface, cavity or organ.

What are goblet cells?

Specialised mucus-secreting epithelial cells found in the lining of of respiratory and digestive tracts.

What is mucus?

A slippery, sticky secretion composed of water, glycoproteins and salts. It acts as a physical barrier, lubricant, and trapping mechanism to protect epithelial surfaces throughout the body.

Define diffusion.

Net movement of substances from a high to low concentration until equilibrium is reached.

What is the structure and function of the trachea?

Structure: Tube supported by C-shaped rings of cartilage and lined with ciliated columnar epithelium and goblet cells.

Function: Transports air to and from the lungs. Goblet cells secrete mucus to trap particles, and cilia move the mucus towards the throat.

What is the structure and function of the bronchi?

Structure: Two branches of the trachea that enter the lungs, containing cartilage and ciliated epithelium.

Function: Carry air from the trachea into each lung and help filter particles using mucus and cilia.

What is the structure and function of the bronchioles?

Structure: Smaller branches of the bronchi with smooth muscle, elastic fibres and thin endothelial lining in their walls and no cartilage.

Function: Carry air to the alveoli and regulate airflow by constricting or dilating.

What is the structure and function of the alveoli/

Structure: Tiny air sacs with thin squamous epithelial walls (one cell thick), elastic fibres to help expand and recoil, large surface area, and rich blood supply.

Function: Site of rapid gas exchange where oxygen diffuses into the blood and carbon dioxide diffuses out of the blood.

Define the term tissue

A group of similar cells that work together to perform a specific fucntion.

Why is squamous tissue suitable for effective gas exchange in the alveoli?

They are one cell thick therefore a short diffusion pathway.

Describe the role of the goblet cells in the lungs.

Goblet cells produce mucus to trap pathogens and dust that gets inhaled in the lungs.

Describe the role that cilia plays in the lungs.

Cilia are hair-like projections that sweeps backwards and forwards to move mucus produced by the goblet cells up and out of the lungs.

State the equation for Fick’s law

Rate of diffusion=(surface area of gas exchange x difference in concentration)/thickness of membrane.