The Respiratory System Copyright Pearson Prentice Hall

The Human Respiratory System Epiglottis Trachea Nose Pharynx Larynx Lungs Bronchi Mouth Diaphragm Bronchioles The respiratory system is responsible for the exchange of oxygen and carbon dioxide. Air moves through the nose, pharynx, larynx, trachea, and lungs. After reaching the lungs, the trachea branches into smaller and smaller tubes called bronchioles, which end in alveoli, or air sacs. Copyright Pearson Prentice Hall

Organs in the Respiratory System STRUCTURE FUNCTION Nose / nasal cavity  warms, moistens, & filters air as it is inhaled Pharynx Aka “throat”- the passageway for air, leads to trachea & esophagus Larynx  the voice box, where vocal chords are located Epiglottis Flap that covers esophagus or trachea Trachea  aka “windpipe”  Trachea is lined with fine hairs called cilia which filter air before it reaches the lungs

Organs in the Respiratory System STRUCTURE FUNCTION Bronchi  two branches at the end of the trachea, each lead to a lung Bronchioles  a network of smaller branches leading from the bronchi into the lung tissue & ultimately to air sacs Alveoli  the “air sacs” in the lung where gases are exchanged Diaphragm Muscle below ribcage that controls breathing

What Is Respiration? In biology, respiration means different things. Cellular respiration is the release of energy from the breakdown of food in the presence of oxygen (occurs in your cells!) At the organism level, respiration is the process of gas exchange - the release of carbon dioxide and the intake of oxygen that occurs between red blood cells (RBCs) and alveoli in lungs Breathing is the actual mechanical intake of air

Breathing BREATHING Lungs are sealed in membranes inside the chest cavity. At the bottom of the cavity is a large, flat muscle known as the diaphragm. During inhalation the rib cage rises and the diaphragm contracts, increasing the size of the chest cavity.

Breathing Inhaling: Diaphragm contracts down and the rib cage rises up & out. This creates a partial vacuum inside the cavity. The change in pressure causes air to rush in. During inhalation the rib cage rises and the diaphragm contracts, increasing the size of the chest cavity.

Breathing Exhaling: Diaphragm relaxes and moves up. Air Exhaled Exhaling: Diaphragm relaxes and moves up. Ribcage moves down and in. Air is pushed out of the lungs. Rib cage lowers During inhalation the rib cage rises and the diaphragm contracts, increasing the size of the chest cavity. Exhalation

How Breathing Is Controlled Breathing is controlled by the brain. Brain monitors carbon dioxide in the blood, and send signals to diaphragm to increase/decrease breathing rate as necessary

So what’s a hiccup? Muscle spasms in your diaphragm Longest bout of hiccups – 68 years!!!

Pathway of Air Mouth/Nose  Pharynx  Trachea  Bronchi  Bronchioles  Alveoli  into capillaries! (then reverse it!)

Focus on Alveoli Alveoli are grouped in clusters at the end of each bronchiole A network of capillaries surrounds each alveolus.

Gas Exchange Gas exchange takes place in the alveoli. Oxygen diffuses from alveoli into the blood. Carbon dioxide diffuses from blood into the alveoli. CO2 Gas exchange occurs by diffusion across the membrane of an alveolus and a capillary. Capillary

Gas Exchange

Relationship between Respiratory & Circulatory Systems Could one function without the other? Pickup O2 but no way to get to cells! Blood is circulating but no way to get O2! Lungs (get O2, leave CO2) Heart (right side) Heart (left side) Cells in Body (leave O2, get CO2)