The Human Body:Respiratory System

Textbook Chapter 34Review Book Topic 1

Function

Sustain cellular respiration by supplying oxygen to body cells and removing carbon dioxide waste from cells

Two processes:

Breathing

Respiration

Breathing Mechanical movement of air into and out of the

lungs

Respiration External respiration ~ exchange of gases between

the atmosphere and the blood in the lungs

Internal respiration ~ exchange of gases between the blood and the body’s cells

Structure

Made up of: Nasal passages Pharynx Larynx Epiglottis Trachea Lungs Bronchi Bronchioles Alveoli Diaphragm

Path of Air

Overall

Air travels from the outside environment to the lungs where it passes through the alveoli

Step by Step

Air enters your mouth or

nose

Hairs in nose filter out dust

and other large particles in the air

Cilia line nasal passages/tubes to trap foreign particles and prevent them from entering the lungs

Mucus membranes beneath the cilia warm and moisten the air

Filtered air passes through upper throat (pharynx)

Epiglottis is a flap of tissue which covers the opening to the larynx to prevent food from entering the lungs

• Allows air to pass from

larynx to trachea

(windpipe) which branches

into two bronchi, leading

to the lungs

Lungs are the largest organ of the respiratory system

• Gas exchange occurs here

Each bronchi branches into smaller bronchioles which continue to decrease in size ending each in an individual air sac known as a alveolus

• Alveoli are thin walled (1 cell thick) to allow for gas exchange

• Surrounded by very thin capillaries

Gas Exchange

In alveoli, oxygen diffuses across the moist, thin walls into capillaries and then into red blood cells

Oxygen is transported by the blood to be released into body cells during internal respiration

Carbon dioxide diffuses out of the capillaries, into the alveoli and into the lungs to be returned to the atmosphere through external respiration

Process of Breathing

Brain directs the rate of breathing by responding to internal stimuli that indicate how much oxygen the body needs

When carbon dioxide concentration is high, breathing rate increases to increase oxygen concentrations

Inhalation ~ act of taking air into the lungs

Diaphragm contracts causing the chest cavity to expand as the diaphragm moves down

This allows air to move into the lungs

Exhalation

Diaphragm relaxes and returns to normal resting position, reducing the size of the chest cavity

Air naturally flows out from greater pressure of lungs

Disorders

Lung Disorder Description

Asthma Respiratory pathways become irritated and bronchioles constrict

Bronchitis Respiratory pathways become infected, resulting in coughing and production of mucus

Emphysema Alveoli break down, resulting in reduced surface area for gas exchange

Pneumonia Infection of the lungs that causes alveoli to collect mucus material

Pulmonary tuberculosis A specific type of bacteria infection in the lungs, resulting in less elasticity of blood capillaries surround alveoli, decreases the effectiveness of gas exchange

Lung Cancer Uncontrolled cell growth in lung tissue can leas to persistent cough, shortness of breath, bronchitis or pneumonia, and can lead to death

Respiratory System BrainPop