The Respiratory System

Functions

• The respiratory system moves oxygen from the outside environment into the body.

• It also removes carbon dioxide and water from the body.

Organs

• Air travels in and out of the organs of the respiratory system;– nose– pharynx– larynx– trachea– bronchi– lungs

• bronchioles• alveoli

• respiration – the transport of oxygen from outside the body to cells and tissues, and the transport of carbon dioxide and wastes away from cells and to the environment.

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Why do we Breathe?• cellular respiration - (break down of

glucose for energy) requires oxygen as a reactant.

• Respiration also produces water and carbon dioxide which can leave the body through the lungs

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The Air You Breathe

• The air you breathe comes from the atmosphere – 21% oxygen– 78% nitrogen– 1% other gases

• Your body does not use most of the air you inhale

• What you don’t need is exhaled

The Path of Air

• As air moves the organs, it is warmed, moistened, and bacteria and other small particles are removed.

In the nose …

• Air is warmed• Nose hair filters dust and other small

things out. • Mucus also traps small particles, dust,

and bacteria.

the pharynx

• pharynx - (throat) is a long hollow tube that connects the nose to the trachea.

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the larynx

• larynx – part of the throat where the vocal cords are located.

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the trachea• trachea - connects the pharynx to the

bronchi. It is lined with mucus and small hairs that trap particles.

• You can feel the ridges of the trachea by running your finger down your neck

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bronchi• bronchi - passages that direct air into

the lungs.– Left bronchus goes to the left lung– Right bronchus goes into the right lung

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the lungs• lungs - The main

organs of the respiratory system that provide oxygen to the body.

• The bronchi, bronchioles, and alveoli are all inside the lungs.

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bronchioles

• bronchioles - smaller branches that come off of the bronchi.

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alveoli

• alveoli - smallest structure in the lungs where gas exchange takes place between the lungs and the blood.

• The walls of the alveoli are very thin which allows the gases to diffuse back and forth.

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Gas Exchange

• After air enters the alveoli, oxygen passes through the wall of the alveoli, into the capillary that surrounds it , then into the artery headed to the heart.

• At the same time, carbon dioxide and water pass from the vein into the capillary, then into the alveoli where they are exhaled.

Gas Exchangealveoli

• diaphragm – dome-shaped muscle below the lungs that causes us to inhale and exhale.

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How You Breathe

• You breathe on average 20,000 times a day

• Breathing speeds up when you exercise

• Breathing slows down when you are asleep

• Both involuntary and voluntary muscles and nervous system helps you breathe

Speaking

• Inside your trachea are vocal cords• Vocal cords stretch across the opening• Your vocal cords work like the neck of

a balloon when it is stretched• Air passes over the vocal cords,

making them vibrate which produces sound– Low – vocal cords contract & shorten– High – vocal cords relax & lengthen

Body systems that work with the respiratory system;

• muscular system to pull air into the lungs

• circulatory system to carry the oxygen in and carbon dioxide out

• digestive system to provide energy