RESPIRATORY ZONE - components of the respiratory system and related their structures to their functions

What structures make up the respiratory zone?

respiratory bronchioles, alveolar ducts, alveolar sacs, alveoli

What is the function of the respiratory zone?

site of gas exchange, contains thin-walled alveoli

Why do alveoli have a large surface area?

to maximise gas exchange efficiency

What are alveoli?

tiny air sacs in the lungs, primary site of gas exchange

What are Type I alveolar cells?

thin epithelial cells, form most of the respiratory membrane, allow gas diffusion

What are Type II alveolar cells?

produce surfactant, reduce surface tension, prevent alveolar collapse

What is the function of alveolar macrophages?

remove debris, remove pathogens, keep alveoli sterile

What surrounds alveoli?

dense capillary networks, enable rapid gas exchange

What forms the respiratory membrane?

Type I alveolar cell, fused basement membrane, capillary endothelial cell

Why is the respiratory membrane thin?

facilitates rapid gas exchange, approximately 0.5 micrometres thick

What coats the alveolar surface?

alveolar fluid, prevents damage, facilitates gas exchange, contains surfactant

What is the function of surfactant?

reduces surface tension, prevents alveolar collapse

What are the lungs?

large spongy elastic organs for gas exchange

How many lobes does the left lung have?

two lobes

How many lobes does the right lung have?

three lobes

Where are the lungs located?

thoracic cavity, within pleural cavities

What is the visceral pleura?

membrane covering the lung surface

What is the parietal pleura?

membrane lining the thoracic wall

What is the pleural space?

space between pleural layers, contains pleural fluid

What is the function of pleural fluid?

lubricates pleural surfaces, allows smooth lung movement, helps lungs adhere to thoracic wall

What does pulmonary circulation do?

delivers deoxygenated blood to lungs via pulmonary arteries, returns oxygenated blood via pulmonary veins

What does bronchial circulation do?

delivers oxygenated blood to lung tissue

Which vessels deliver deoxygenated blood to the lungs?

pulmonary arteries

Which vessels return oxygenated blood to the heart?

pulmonary veins

What do sensory fibres in the lungs detect?

stretch, irritants, send signals to respiratory centre

What do sympathetic fibres do in the lungs?

dilate bronchioles, increase airflow

What do parasympathetic fibres do in the lungs?

constrict bronchioles, reduce airflow