Respiration  Internal –Exchange of gases between blood and cells –Cellular respiration  External –Exchange of gases (oxygen & carbon dioxide) between an organism and the environment

Respiratory System  Group of organs working together to exchange gases

Gas Exchange  Skin –Gas exchange occurs across the skin into the blood supply –Ex- earthworm  Spiracles –Tiny air holes in body extend inward to body cells –Ex- insects

Gas Exchange  Gills –Gas exchange between water and blood through blood vessels in gills –Ex- fish  Lungs –Gas exchange between air sacs of lungs and blood –Ex- mammals

Gas Exchange  Multiple methods –Frog  Gills as tadpole  Lungs  Skin

Breathing  Breathing- process of taking in and forcing out air  Inhalation (inspiration)- –Taking in air –Rib cage moves up/out –Diaphragm moves down –Increase volume- decrease pressure, air forced in

Breathing  Exhalation (expiration) –Forcing out air –Rib cage moves down/in –Diaphragm moves up –Decrease volume- increase pressure, air forced out

Human Respiratory System  Breathing rate –Normal is 16 – 20 per minute –Varies greatly with exercise –Controlled by the levels of carbon dioxide in the blood –Acidity of the blood is changed, this is detected and breathing increases

Human Respiratory System  Lung Capacity –Vital Capacity  Largest amount of air that can be exhaled –Expiratory Reserve  Amount of air left in the lungs after a normal exhale, but can be expelled –Tidal Volume  Amount of air taken in or exhaled during normal breathing

Human Respiratory System  (h) Nose/Nasal Cavity- –Conditions the air, cleans, warms, & moistens  (a) Pharynx- –Throat, passage way for air, food, & drink  (b) Epiglottis- –Flap that covers the top of the trachea when swallowing food and drink

Human Respiratory System  (c) Trachea- –Windpipe, held open by cartilage rings, carries air from throat to chest  (g) Larynx- –Adams Apple, voice box, vocal cords located here  (d) Bronchi- –Subdivision of trachea, carries air from trachea to lungs

Human Respiratory System  (f) Bronchioles- –Subdivisions of bronchi in the lungs  (k) Alveoli- –Tiny air sacs at the ends of the bronchioles, functional unit of the lung, exchange of gases between lung and capillaries

Human Respiratory System  (m) Arrow- Carbon Dioxide –Showing carbon dioxide moving from capillary to alveolus.  (l) Arrow- Oxygen –Showing oxygen moving from alveolus to capillary.

Human Respiratory System  (i) Pulmonary arteries- –Transports oxygen poor blood from the heart to the lungs, only arteries to carry oxygen poor blood  (j) Pulmonary veins- –Transports oxygen rich blood from the lungs to the heart, only veins to carry oxygen rich blood

Human Respiratory System  (e) Diaphragm- –Muscular sheet that separates the thoracic and abdominal cavities, aids in breathing