Lesson 2: The Respiratory System Overview

Inhalation (Inspiration)

Take in oxygen

Exhalation (Expiration)

Gives off carbon dioxide

Nasal Cavity

Anterior opening of the respiratory system

Nostrils (External nares)

• Anterior opening of the nasal cavity

• Serve as the entry and exit points for air during breathing.

Nasal Vestibule

• Most anterior part of the nasal cavity

• Lined with coarse hairs and skin, it helps trap large particles.

Turbinates

• Tissue ridges at the side wall of the nasal cavity

• Warms the nose and moisturize airflow

Choanae (Internal nares)

• Posterior opening of the nasal cavity leading to nasopharynx

• Allow air passage from the nasal cavity to the throat.

Nasopharynx

• Upper part of the throat behind the nose

• Functions as an air passageway only

Adenoids

• Produce antibodies (WBC) and fight infection

Eustachian Tube (Pharyngotympanic tube)

• Links the ear to the nasopharynx

• Equalizes air pressure on both sides of the eardrum, especially during changes in altitude.

Sinuses (Frontal & Sphenoid)

• Produce mucus to moisturize the nose and protect from dirt, dust, pollutants, and microorganisms

Pharynx

• Known as throat, located behind the nasal cavity, above the larynx and esophagus

Uvula

• Finger-shaped tissue that hangs down the soft palate, closes the pharynx, and prevents food from entering the nasal cavity

Glottis

• Opening between the vocal cords and entrance to the larynx

• Plays a role in producing sound

Larynx

• Sound-producing organ for phonation

Epiglottis

• Flap structure at the superior end of the larynx that guards the opening of the larynx and esophagus

Thyroid Cartilage

• Commonly known as the 'Adam's apple'

• Protects the vocal cords and provides muscle attachment

Cricoid Cartilage

• Involved in the opening and closing of the airway and attachment for the inferior horn of thyroid cartilage & muscles

Trachea

• Connects the pharynx and larynx to the lungs and serves as a passageway for air

Bronchi

• Each bronchus branches to several bronchioles

• Deliver air to the right and left lungs.

Alveoli

Tiny air sacs of the lungs for gaseous exchange

Lungs

• Filamentous respiratory organs that surface area for gas exchange in water increase

• Saclike respiratoryorgans with branching tubes that deliver air to a respiratory surface

Snails and slugs

spend some time on land have a lung instead of, or in addition to, gills

Book Lungs

• Some spiders also have thin sheets of respiratory tissue that exchange oxygen with a respiratory pigment

Surfactant cell

Contains lipid and protein; lowers surface tension in the alveoli

Endothelial cell

Squamous cell lining the inner wall of the alveoli

Epithelial cell

Type 1 cell forming the alveolar wall

Macrophage

Phagocytic cell ingesting infectious agents

Integumentary exchange

Gas exchange across the skin in some invertebrates that live in aquatic or damp environments

Gills

Filamentous respiratory organs that increase surface area for gas exchange in water

Tracheal system

Branching tracheal tubes in insects and spiders that open to the surface through spiracles

Fish

Use gills to extract oxygen from water

Reptiles, Birds, Mammals

Exchange gases through paired lungs, ventilated by chest muscles

Gas Exchange in Invertebrates

Occurs across the body surface or gills of aquatic invertebrates

Countercurrent flow

Blood flows through gills in the opposite direction of water flow to aid gas exchange

Amphibians

Exchange gases across their skin and at respiratory surfaces of paired lungs

Birds

Have the most efficient vertebrate lungs with air sacs allowing oxygen-rich air to pass respiratory surfaces on both inhalation and exhalation