Human Breathing System Quiz

Human Breathing System Overview

• Begins at the mouth and nostrils, where pathogens can enter.
• Defense mechanisms include cilia and mucus; mucus traps particles and pathogens, cilia move mucus to the pharynx.
• Swallowed mucus is neutralized by stomach acid.

Nasal Functionality

• Air filtration occurs in the nose; air is warmed and moistened as it passes through nasal cavities.
• Chemoreceptors detect chemicals, contributing to the sense of smell and safety checks (i.e., food edibility, predator presence).

Epiglottis

• Flap of cartilage preventing food from entering the trachea during swallowing.

Trachea

• Main airway to the lungs, supported by rings of cartilage to prevent obstruction.

Bronchus and Bronchioles

• Bronchus is the first tracheal division leading to each lung.
• Bronchioles are further subdivisions allowing air passage to all lung areas.

Alveoli

• Sacs where gas exchange occurs, shaped like grapes for large surface area.
• Thin walls and dense capillary networks enhance gas diffusion efficiency.

Pleural Membranes

• Moist membranes surrounding the lungs, preventing tissue abrasion during breathing.
• Inflammation leads to pleurisy, a painful condition.

Diaphragm

• Dome-shaped muscle that separates thoracic and abdominal cavities.
• Contracts to flatten, increasing thoracic cavity volume and facilitating breathing.

Ribs and Intercostal Muscles

• Twelve pairs of ribs protect the lungs and heart.
• Intercostal muscles lift the ribcage when contracted, increasing thoracic cavity volume.

Adaptations for Efficient Breathing

• Capillaries near alveoli surfaces allow efficient gas exchange.
• Moist environments necessary for oxygen and carbon dioxide diffusion.
• Structures possess a large surface area and elastic properties aiding lung function.

Breathing Mechanism

• Controlled subconsciously by the Medulla Oblongata, which monitors blood O₂ and CO₂ levels via pH changes.
• Increased CO₂ raises breathing rate; decreased CO₂ has the opposite effect.

Inhalation Process

• Active process: diaphragm contracts and flattens, intercostal muscles lift the ribcage.
• Results in increased thoracic cavity volume and decreased pressure, drawing air in.

Exhalation Process

• Passive process: diaphragm relaxes, ribcage moves down.
• Decreased thoracic cavity volume increases pressure, pushing air out.

Breathing Disorders: Asthma

• Most common breathing disorder in Ireland, often triggered by allergens like dust mites and pet dander.
• Regular cleaning can alleviate symptoms; bronchodilator inhalers are effective treatments.