Function of Respiration
SBI3U
RESPIRATORY SYSTEM
• PRIMARY function: BREATHING (for gas exchange):1. uptake oxygen needed by the cells2. release carbon dioxide produced by the cells
(remove waste, pH balance of blood)
• Also used to produce SOUND
Why do we need to breath oxygen? Think of your previous digestive unit!
cellular respiration:
glucose + oxygen = carbon dioxide and water
HUMAN ADAPTATIONS
•For efficient gas exchange to occur:
1. Water must be present at the respiratory surface.
Adaptation: Human lung located within the body cavity
which contains a lot of water and air is moistened when it enters lungs.
(Compare this to worm, fish, frog, insect…)
Types of respiration in animals
Types of respiration in animals
• Outer skin– Earthworm
• Gills– Fish
• Treacheal System– Insects
• Lungs– Land animals
http://www.youtube.com/watch?v=HV60yTvy3Mk
http://www.youtube.com/watch?v=XEIRlw5rCUk
Why is this scenario physiologically impossible?
HUMAN ADAPTATIONS
2. The respiratory surface must be large
Adaptation:
Spread out on a flat surface the gas-exchange surface is how big?
a) Half of a basketball courtb) Half of a tennis courtc) Ping pong table
The Human Respiratory System
Nasal cavityPath taken by airPath taken by food
The Human Respiratory SystemPart Function Special Features
Nasal passages
Point of entryFilter, warm, moisten air
Mucus, hairs, many capillaries, sinus cavities, turbinates
Oral Cavity
Warm and moisten air
Alternate space for gas exchange, no filtration
The Human Respiratory System
Nasal CavityPath taken by airPath taken by foodPharynxEpiglottisEsophagus
The Human Respiratory System
Part Function Special Features
Pharynx connects nasal and oral cavity to larynx
Cilia in top portion move food towards mouth to be swallowed
Epiglottis A flap that prevents food from entering the lungs by blocking the glottis (opening of trachea)
Small, flexible
The Human Respiratory System
Nasal CavityPath taken by airPath taken by foodPharynxEpiglottisEsophagusTrachea
Larynx
UpperRespiratoryTract
The Human Respiratory System
Part Function Special Features
Larynx Contains the vocal cords – for sound, “voice box”“Adam’s Apple”
two flaps of cartilage, vibrate when air passes through
Trachea Passage of air into 2 bronchi, “windpipe”filter particles up to mouth
~12cm long-Semicircular cartilage rings to prevent collapse -Cilia and mucus
The Human Respiratory System
Nasal CavityPath taken by airPath taken by foodPharynxEpiglottisEsophagusTracheaBronchiBronchioles
Larynx
UpperRespiratoryTract
The Human Respiratory System
Part Function Special Features
Bronchus Each carries air into lungs and splits into many bronchioles
Full cartilage rings for support
Bronchiole Many branches carry air to alveoliAble to change diameter to regulate air flow
Many branched tubes, Smallest passageways, to increase surface areaSmooth muscle wallsNO cartilage rings
The Human Respiratory System
Nasal CavityPath taken by airPath taken by foodPharynxEpiglottisEsophagusTracheaBronchiBronchioles
AlveoliDiaphragm
Larynx
UpperRespiratoryTract
LowerRespiratoryTract
The Human Respiratory System
Part Function Special Features
Alveoli (singular: alveolus)
Site of external respiration (gas exchange)~150 million very thin tiny sacs (large surface area)
Single cell layer thick, surrounded by capillariesCoated with “surfactant” (a lipoprotein) to prevent sticking
Diaphragm Increases and decreases volume of chest cavity
Dome shaped, thin, muscular
The Human Respiratory System
Part Function Special Features
Pleural Membrane
Surrounds lungs and lines chest cavity, reduces friction
Filled with fluid that reduces friction during inhalation