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