The Respiratory System

Respiratory System

!  Lungs and air passages

!  Takes oxygen in and removes carbon dioxide

!  Carbon Dioxide is considered metabolic waste from cells, that occurs after cells convert food to energy

!  Works continuously or death occurs in ���4–6 minutes

Respiratory Structures Nose Sinuses Pharynx—throat Larynx—voice box Trachea—windpipe Bronchi Alveoli Lungs

Respiratory System !   Nose: has 2 nostrils that

lead to the nasal cavities

!   As air enters the cavity, it is warmed, filtered, and moistened

!   The mucous membrane produces mucous that helps to trap pathogens and dirt

!   Contains Cilia: hairlike structures that trap dirt

!   Olfactory sensors are in the nose (sense of smell)

!   Sinuses: Cavities in the skull around the nasal area

!   Connected to nasal cavity by short ducts

!   Lined with mucous membrane that warms and moistens air

!   Provides resonance for the voice

Respiratory Structures

!   Pharynx or throat: Lies directly behind the nasal cavities

!   As air leaves the nose it enters the pharynx

!   3 sections:

! Nasopharynx: upper portion behind nasal cavities

!   Adenoids and auditory tube openings are here

!   Oropharynx: Middle section located behind the oral cavity

!   Receives air from nasopharynx and food and air from mouth

!   Laryngopharynx: Bottom of pharynx

!   Branches in to trachea, which carries air to and from the lungs, and the esophogus that carries food to the stomach

Pharynx

Respiratory Structures

!   Larynx: Voice Box

!   Lies between pharynx and trachea

!   Has framework of cartilage commonly known as the Adam’s apple

!   Contains two folds called vocal cords

!   Opening between the vocal cords is the glottis

!   Epiglottis: piece of cartilage that closes the opening during swallowing to prevent food from entering the lungs

!   Trachea: wind pipe

!   Tube extending from larynx to center of chest

!   Carries air between pharynx and bronchi

!   Series of C-shaped cartilage that are open at the back to allow them to flex

Respiratory Structures

!   Bronchi:

!   2 divisions of trachea near the center of the chest, right and left bronchus

!   Each bronchus enters the lung and carries air from the trachea to the lung

!   Inside the lungs, the bronchus divide in to smaller and smaller branches called bronchioles

!   Smallest bronchioles end in air sacs called alveoli

!   Alveoli: Air sacs that resemble a bunch of grapes

!   Adult lung contains approximately 500 million alveoli

!   Contains a rich network of blood capillaries

!   Capillaries allow oxygen and carbon dioxide to be exchanged between blood and lungs

!   Inner surface of alveoli is covered with surfactanct

!   Lipid substance

!   Helps prevent alveoli from collapsing

Respiratory Structures

!   Lungs: Organs that containing divisions of alveoli and bronchi

!   Right lung has 3 sections, or lobes: superior, middle, and inferior

!   Left lung is smaller because of the heart being on the same side

!   Pleura: membranes or sac enclosing each lung

!   Consists of 2 layers of membrane:

!   Visceral Pleura: outside of lung

!   Parietal Pleura: chest wall

!   Pleural space: Located between the 2 layers

!   Filled with a thin layer of fluid that lubricates the membranes and prevents friction as lung expand for breathing

Lungs and structures within

Ventilation

!   Process of breathing:

!   Inspiration—inhalation: taking air in the lungs !   Diaphragm and intercostal muscles in chest wall contract to expand

rib cage for lungs to fill with air: gas exchange occurs in alveoli

!   Expiration—exhalation: air leaves lungs !   Diaphragm and intercostal muscles relax: air is forced out of lungs

Respiration

!   Process of respiration is controlled by the medulla oblangata

!   This process is typically involuntary, however, people can control breathing faster or slower

!   A decreased amount of oxygen as seen in certain diseases (asthma, CHF, & emphysema) or increased CO2 will cause the center in increase respiration

!   External Respiration: Exchange of O2 and CO2 between lungs and blood stream

!   Internal Respiration: Exchange of CO2 and O2 between cells and blood stream

Internal vs. External Respiration