The Respiratory System

Function of the Respiratory System

•  To provide a constant supply of oxygen (O2) to keep your body cells functioning

•  To remove carbon dioxide (CO2) from

the body cells

Structure of the Respiratory System are the Organs

•  Nose •  Mouth •  Nasal cavity •  Pharynx •  Epiglottis •  Larynx

•  Trachea •  Bronchus (bronchi) •  Bronchioles •  Alveoli •  Pleura •  Diaphragm

Lungs

http://www.bbc.co.uk

Nasal Cavity

Nose

Mouth

Bronchus

Bronchiole

Alveolus

Diaphragm

Throat (pharynx)

Windpipe (Trachea)

Left Lung

Ribs

Mouth & Nose •  Brings air (O2) into the body •  Carbon Dioxide leaves the body through the

mouth and nose •  Nasal hairs in nostrils filter and trap dust. •  Air is not filtered as much when it enters in

through your mouth.

Nasal cavity

•  Warms & moistens air •  Glands that produce sticky mucus line

the nasal cavity –  traps dust, pollen, and other materials that

were not trapped by nasal hairs – cilia sweep mucus and trapped material to

the back of the throat where it can be swallowed

Pharynx (Throat)

•  Tube-like passageway used by food, liquid, and air

•  At the lower end of the pharynx is a flap of tissue called the epiglottis – covers the trachea during swallowing so

that food does not enter the lungs

epiglottis

Larynx •  “Voice box” •  The airway to which

two pairs of horizontal folds of tissue, called vocal cords, are attached

Trachea (Windpipe)

•  Air-conducting tube •  Connects the larynx with the bronchi •  Lined with mucous membranes and

cilia •  Contains strong cartilage rings which

hold the trachea open. Without these rings your trachea might close off and air would not be able to get to and from your lungs.

Bronchi •  Two short tubes that branch off the

lower end of the trachea •  Carry air into the lungs. •  Singular - bronchus

Bronchioles

•  bronchi tubes split up, like tree branches, and get smaller and smaller inside your lungs.

•  The tiny branches of air tubes in the lungs are bronchioles

•  Connect bronchi to alveoli

Alveoli

•  Tiny, thin-walled, grapelike clusters at the end of each bronchiole

•  Surrounded by capillaries •  Where carbon dioxide and oxygen

exchange take place •  Singular - alveolus

Bronchi and

Alveoli Picture

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Pleura

•  Membrane lining the lungs and chest cavity

Diaphragm •  Muscle wall between the chest and the

abdomen that the body uses for breathing

•  Lungs expand and contract in response to changes in pressure inside the chest cavity.

•  The diaphragm flattens to cause the chest to expand and air is pulled into the lungs.

•  When the diaphragm relaxes, the chest collapses and the air in the lungs is forced out.

Diagram of Diaphram

Respiratory System Animation

Inhalation

•  Breathing in •  Body gets oxygen from the air •  Rib muscles contract to pull ribs up and

out •  Diaphragm muscle contracts to pull down

the lungs •  Tissue expands to force (pull) in air.

Exhalation

•  Breathing out •  Get rid of carbon dioxide •  Rib muscles relax •  Diaphragm muscle relaxes •  Tissue returns to resting position and

forces (pushes) air out

Breathing and Respiration are NOT the same thing!

Breathing

• Moving air in and out of the lungs

Respiration

•  Chemical reaction that releases energy

C6H12O6 + 6O2 à 6CO2 + 6 H2O + Energy

Relationship to Digestive System

•  Cellular respiration requires glucose and oxygen to release energy to the body

•  C6H12O6 + 6O2 à 6CO2 + 6 H2O + Energy •  Oxygen is provided by the respiratory

system •  Glucose is provided by the digestive system •  (glucose is made during photosynthesis)

Relationship to Nervous System • The respiratory system is under control of

the involuntary and voluntary nervous system.

�We don’t think about breathing. �The autonomic nervous system controls

breathing in response to the amount of carbon dioxide in the blood.

Relationship to Nervous System • The respiratory system is under control of

the involuntary and voluntary nervous system.

�We don’t think about breathing. �The autonomic nervous system controls

breathing in response to the amount of carbon dioxide in the blood.

Relationship to Nervous System �Humans can decide to hold their breath. �The respiratory system is then controlled

by the somatic nervous system. �If you pass out from holding your breath,

your autonomic nervous system will take over and return the blood gasses to normal.

Respiratory Information

Each lung is about the size of a football. The lungs fill the area from the collarbone to

the bottom of the ribs. Lungs are the only organ in the body light

enough to float. There are 300-500 million alveoli having a

total surface area or about 75 m2 in adults (about the size of three living rooms).

Respiratory Information •  If all the capillaries that surround the

alveoli were unwound and laid end to end they would extend about 620 miles.

•  At rest, the body takes in and breathes out about 10 liters of air each minute.

•  The right lung is slightly larger than the left.

•  The highest recorded "sneeze speed" is 165 km per hour.

Respiratory Information

•  The surface area of the lungs is roughly the same size as a tennis court.

•  We lose half a liter of water a day through breathing. This is the water vapor we see when we breathe onto glass.

•  A person at rest usually breathes between 12 and 15 times a minute.

•  The breathing rate is faster in children and women than in men.