Gas Exchange & Breathing
CONCEPTUALDescribe the structure of the human gas exchange system (trachea, bronchi, bronchioles, alveoli) and explain how the mechanism of breathing — using pressure changes from rib and diaphragm movement — moves air in and out of the lungs
Mastery Evidence
- Labels a diagram of the lungs showing trachea, bronchi, bronchioles, and alveoli
- Explains that breathing in lowers air pressure in the chest and air rushes in
- Describes how the structure of alveoli (large surface area, thin walls, good blood supply) aids gas exchange
Assessment Prompt
“If [child] took a deep breath after running, could they explain what's happening in their lungs — how the air gets in, where the oxygen crosses into the blood, and how carbon dioxide leaves?”
Curriculum Standards2 alignments
KS3.Sci.Bio.GasExchange.1The national curriculum in Englandthe structure and functions of the gas exchange system in humans, including adaptations to function
KS3.Sci.Bio.GasExchange.2The national curriculum in Englandthe mechanism of breathing to move air in and out of the lungs, using a pressure change
Prerequisites2
- Cells to Organ SystemssoftAges 11—12
- How Diffusion WorkshardAges 12—13
Show full prerequisite tree
- Cells to Organ Systems soft
The gas exchange system is an organ system — hierarchy concept provides structural context
- Plant Cells vs Animal Cells hard
The cell-to-organism hierarchy builds on understanding that different cell types exist
- Parts of Plant and Animal Cells hard
Comparing plant and animal cells requires knowing the components found in each
- Cells Under the Microscope hard
Understanding cell components requires first knowing that cells are the fundamental unit of life
- How Diffusion Works hard
Gas exchange at the alveoli is driven by diffusion — the mechanism must be understood first
- Parts of Plant and Animal Cells hard
Diffusion in and between cells requires knowing about the cell membrane as a selectively permeable boundary
- Cells Under the Microscope hard
Understanding cell components requires first knowing that cells are the fundamental unit of life
Unlocks2
- Aerobic RespirationhardAges 12—13
- Heart Structure & Double CirculationhardAges 12—13