Repiratory System

Lungs & Air Passages

• Nose, Pharynx, larynx, trachea,lungs bronchi, alveoli
• Responsible for: taking in O2 & Removing CO2
• Body has 4-6 minute supply of O2
• Must work continuously or death will occur

Nose

• Has 2 nostrils or nares: opening through which air enters
• Nasal septum: partition of cartilage & divides nose into 2 hollow spaces called nasal cavities

Nasal Cavities

• lined with mucous membrane
• Rich blood supply
• air enters and is warmed, filtered and moistened
• mucous also helps trap pathogens and dirt

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• cilia: tiny hair like structures which also trap dirt and pathogens, pushing them toward esophogus to be swallowed
• olfactory receptors for the sense of smell
• nasolacrimal ducts drain tears from the eye into the nose to provide additional moisture for the air

Paranasal Sinuses

• hollow air-conditioning spaces within the skull
• cavities in the skull around the nasal area
• connected to the nasal cavity by short ducts
• lined with mucous membrane that warms & moistens air
• Provide resonance for the voice

Pharynx

• the throat
• lies behind nasal cavities
• as air leaves nose it enters the pharynx

Pharynx has 3 sections

• Nasophyarynx
• Oropharynx
• Laryngopharynx

Nasopharynx

• upper portion behind nasal cavity
• contains the pharyngeal tonsils or adenoids (lymphatic tissue) and the auditory (eustachian) tube openings

Oropharynx

• middle section located behind the oral cavity
• contains the palatine tonsils (two rounded masses of lymphatic tissue)
• Received both air from the nasopharynx and food and air from the mouth

Laryngopharynx

• bottom section of the pharynx
• branches into the trachea, which carries air to and from the lungs, and the esophagus - the tube that carries food to the stomach

Epiglottis

• flap of cartilage attached to the root of the tongue
• prevents choking or aspiration of food
• acts as a lid over the opening of the larynx

Larynx

• voice box
• lies between the pharynx and trachea
• cartilage "Adam's Apple"
• contains 2 folds called the vocal cords
• opening between the vocal cords is glottis
• air leaves lungs, vibrates cords makes sound
• Tongue and lips makes pronounciations

Trachea

• windpipe
• tube 4.5" larynx to the chest
• carries air between pharynx and bronchi
• c-shaped cartilage, open on the dorsal side.

Bronchi

• two divisions
• 1. Right and Left Bronchi
• 2. Right bronchus is shorter, wider and extends more vertically than the left bronchus

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• each bronchi enters a lung. carries air from trachea to the lungs
• In the lungs, bronchi continue to divide into smaller and smaller bronchi
• Smaller branches are called bronchioles
• Smallest bronchioles, called terminal bronchioles; end in the air sacs called alveoli

Alveoli

• air sacs; looks like grapes
• 300 million alveoli
• one layer of squamous epithlelium tissue
• rich blood supply of capillaries
• capillaries allow for O2 and CO2 exchange between blood and lungs
• inner surface of lungs filled with surfactant
• 1. lipid or fatty substance helps prevent alveoli from collapsing

Erythrocytes

• carry O2 to all parts of the body
• carry CO2 to the lungs for exhalation

Lungs

• organs that contain divisions of bronchi and alveoli
• R lung has 3 lobes
• L lung has 2 lobes & smaller
• located in thoracic cavity
• Hilum: tubes & vessels enter & exit
• extend from clavicle to the diaphragm

Diaphragm

• a muscular partition
• separates the thoracic from abdominal cavity
• helps in breathing
• Contracts & Relax

Pleura

• two layers
• 1. visceral pleura inner layer closest to lung
• 2. parietal layer attached to chest wall, closest to ribs
• Pleura Space: in between the 2 layers, lubrication prevents friction

Pathway of air

• nose
• nasal cavities and paranasal sinuses
• Pharynx (tonsils)
• Larynx (epiglottis)
• Trachea
• Bronchi
• Bronchioles
• Alveoli
• Lung capillaries