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Gas Exchange - Coggle Diagram
Gas Exchange
Cells and Tissues
Ciliated Epithelial Cells
Function
Beat rhythmically to move mucus upward
Goblet Cells
Function
Secrete mucus containing mucin
Trap dust, pollen, bacteria, and pathogens
Macrophages
Function
Phagocytosis of pathogens and particles
Squamous Epithelial Cells
Function
Thin cells reduce diffusion distance
Cartilage
Function
Supports trachea and bronchi
Prevents collapse during breathing
Smooth Muscle
Function
Changes bronchiole diameter
Regulates airflow
Elastic Fibres
Function
Stretch during inhalation
Recoil during exhalation
Help force air out of lungs
Alveoli
Structure
Tiny air sacs
One-cell-thick squamous epithelium
Surrounded by capillaries
Contain elastic fibres and collagen fibres
Adaptations for Gas Exchange
Huge surface area
Thin diffusion pathway
Moist lining
Rich capillary network
Constant ventilation and blood flow
Gas Movement
Oxygen
Alveoli → Blood capillaries → Red blood cells
Carbon Dioxide
Blood capillaries → Alveoli → Exhaled air
Importance of Concentration Gradients
Continuous blood flow removes oxygenated blood
Fresh air maintains oxygen supply
Ensures rapid diffusion
Gas Exchange System
function
exchange oxygen and carbon dioxide between body and atmosphere
Adaptations
Large surface area from millions of alveoli
Thin walls for short diffusion distance
Rich blood supply maintains concentration gradients
Ventilation keeps oxygen high and carbon dioxide low
Moist surface allows gases to dissolve
Trachea
Features
Supported by C-shaped cartilage rings
Lined with ciliated epithelium
Contains goblet cells and mucous glands
Functions
Conducts air to bronchi
Prevents collapse during breathing
Warms and moistens air
Traps particles in mucus
Bronchi
Features
• Branch from trachea into lungs
Supported by irregular cartilage blocks
Ciliated epithelium with goblet cells
Contain elastic fibres and smooth muscle
Functions
Transport air into lungs
Maintain open airways
Filter incoming air
Bronchioles
Features
Smaller branches of bronchi
No cartilage
Surrounded by smooth muscle
Few or no goblet cells in smaller bronchioles
Functions
Control airflow to alveoli
Smooth muscle contracts or relaxes
Widen during exercise for increased airflow
Ventilation and Diffusion
Ventilation
Carbon Dioxide
Breathing refreshes alveolar air
Diffusion
Oxygen
High concentration in alveoli → low concentration in blood
Carbon Dioxide
High concentration in blood → low concentration in alveoli
Protection of the Lungs
Air Cleaning
Nose hairs trap large particles
Mucus traps pathogens and dust
Cilia move mucus toward throat
Swallowing Mucus
Mucus swallowed into stomach
Acid destroys pathogens
Structure of the Human Gas Exchange System
Pathway of Air
Nose / Mouth
Pharynx
Larynx
Trachea
Bronchi
Bronchioles
Respiratory bronchioles
Alveolar ducts
Alveoli