Mammals

• To transports O2 and CO2 from atmosphere to the cells

• Two types – External: use lungs to

exchange gases from the air to our blood

– Internal: to exchange gases between our blood and our cells

Respiratory SystemPurpose:

• Respiratory system is located in the thoracic cavity.– Lies above the diaphragm

– The diaphragm is a large

sheet-like muscle that

divides the thoracic and

abdominal cavities.

• Nasal hairs filter air• Nasal chambers moistens and warms the

air.

Respiratory System1. As you breathe in the air should enter via your nostrils/nares.

2. Air then passes through the pharynxBack of throat area/behind uvulaA common passage for food & air

3. The pharynx directs air into the larynx.

-Larynx is referred to as the Adam’s Apple or Voice Box-Inside the larynx is the vocal cords-As air passes through the vocal cords these thin bands of tissue vibrate allowing you to make sounds.

• 4. The larynx has a flap of tissue protecting its opening called the epiglottis.

• When you swallow this flap closes making a slight sound.– Purpose of the epiglottis is to prevent food

from entering and blocking the respiratory pathway.

• 5.From the larynx the air passes into the trachea.– Known as the windpipe– Approximately 4 ½ inches long– Protected by rings of cartilage

that prevents it from collapsing as

air moves in and out.

• 6. The trachea branches to make two smaller tubes called bronchi– Bronchi direct the air into the lungs– Bronchi divide into smaller branches called

bronchioles.– Bronchioles keep dividing

up to 20 times and eventually

becoming the air ducts.

-Bronchioles, bronchi and trachea are all lined with small hair like structures called cilia.

– Cilia trap foreign particles and push them back towards the throat area.

-Air ducts empty into our air sacs or alveoli.

7. -Alveoli is where our gases are exchanged-Average human has 300,000,000

alveoli.

Respiratory System• Trachea• Bronchi• Bronchioles• Alveoli

• The lungs are surrounded by a double membrane known as the pleura.– Keeps the lungs pressurized so air can move in

and out.– Secretes a slippery fluid which reduces friction

• Mammal lungs are made up of several lobes.– 3 lobes on right side– 2 lobes on left side

• Inspiration:– Air moves into the lungs from the

atmosphere.• Air we breathe is 21% oxygen and .03% carbon

dioxide

• Expiration:– Air moves out of the lungs into the

atmosphere• Air we exhale is 14% oxygen and 5.6% carbon

dioxide.

• Lets examine how this happens……………………………..

• Inspiration/Inhaling:– Air moves into lungs

• Chest expands– Ribcage moves up and

out / expands space– Diaphragm flattens and pushes

down– Abdominal muscles relax.

• Increase volume of thoracic cavity• Pressure inside the cavity is lower than outside the cavity• Air moves from high to low causing air to move into the lungs.

Expiration/Exhaling:Air moves out of lungs

-Chest decreases in size-Ribcage relaxes and moves in-Diaphragm moves up into a concaved shape.-Abdominal muscles contract.

Decrease volume of thoracic cavityPressure inside the cavity is higher than outside the cavityAir moves from high to low causing air to move out the lungs.

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