The Respiratory System SBI 3U January 14th, 2013

The Respiratory System Exchange of oxygen and carbon dioxide between an organism and its external environment Respiratory system: supplies oxygen to cells and removes carbon dioxide CO 2 and breathing rate

More Respiratory Functions Defends body against foreign pathogens Controls pH levels Produces sounds for speaking Helps maintain homeostasis

Components of Respiration Ventilation or breathing Inhalation and exhalation Lungs: specialized structures for respiration (large surface area)

Components of Respiration External Respiration Exchange of gases across the respiratory surface between air sacs or alveoli and the blood Respiratory surface – where oxygen diffuses into organism and CO2 diffuses out

Components of Respiration Internal Respiration Exchange of gases between the blood in capillaries and individual cells in the tissues Oxygen diffuses out of blood and CO2 diffuses in

Components of Respiration Occurs in the mitochondria Glucose as fuel

Anatomy of Respiratory System Upside down tree! Begins with nasal cavity and ends at alveoli Consists of: nose, nasal cavity, pharynx, larynx, trachea, smaller conducting passageways, and lungs

Nasal and Oral Cavities 21% of every air inhalation is oxygen Inhalation from mouth vs. nose Nasal cavity: lined with mucus-secreting cells; helps to moisten and filter incoming air Oral cavity

The Pharynx Pharynx: common path for both air and food Trachea/epiglottis Larynx at top of trachea

The Larynx Adam’s apple Produces sound Vocal chords: two highly elastic folds inside larynx

The Trachea Windpipe Allows air to pass from pharynx into lungs Tough, flexible, c-shaped cartilage rings surrounds the trachea

Respiratory Structures Within the Chest Cavity Trachea divides into 2 branches: right and left bronchi Left bronchus  Left lung Right bronchus  Right lung Lungs Bronchi branch into smaller tubes called bronchioles Alveoli

Respiratory Structures Within the Chest Cavity Bronchioles enter in a cluster of tiny hollow air sacs called alveoli 150 million alveoli in each lung! Occur in clusters Gas exchange