"We are all of

us, five

minutes from

death"

" I learned starkly

that lack of breath

does not feel like

anaesthesia or

sleep; it is like

death"

" I know of no

human experience

that produces

such a spasm of

uncontrolled panic

as does

breathlessness"

" The folds and

convolutions of the

lungs result in a surface

area forty times larger

than the skin's area and

large enough to carpet

a small apartment"

" On an average day

our lungs move

enough air in and out

to fill a medium size

room or blow up

several thousand

party balloons."

" Breathing is

important !

If you've ever

doubted it try

holding your breath

for the next 10

minutes ... "

Four Terms that are not equal ...Four Terms that are not equal ...

Breathing

External respiration

internal respiration

cellular respiration

Breathing is ...

• … the entrance and exit of air into and out of the lungs

• … consists of inspiration (breathing in)

• … and expiration (breathing out)

External Respiration is ...

• … the exchange of gases ( O2 and CO2 ) between air and the blood.

• … lower temperature (lungs)

• … higher pH (7.4)

Internal Respiration is ...

• … the exchange of gases ( O2 and CO2 ) between blood and tissue fluid.

• … higher temperature (tissues)

• … lower pH (7.35)

Cellular Respiration is ...

• … the production of ATP within the cell.

• … requires O2

• … gives off CO2 as a waste product that must be returned to lungs to rid of (external respiration)

Respiratory Tract

Right lung has three lobes

Left lung has two lobes

Fill entire thoracic cavity from pharynx to diaphragm

As air moves in it is ...

• Filtered (hair in nostrils, cilia in trachea)

• Warmed (by surrounding blood vessels)

• Moistened (by wet surfaces of air passages)

You should be able to identify and give functions for the ...

• larynx

• trachea

• bronchi

• bronchioles

•alveoli

•diaphragm and ribs

•pleural membranes

•thoracic cavity

•Eustachian tubes

The larynx ...

• Voice Box• Triangular box …

projects in front of neck as Adam’s apple.

• Glottis is opening covered by epiglottis during swallowing of food

• If food passes epiglottis into larynx, reflex coughing usually expels it.

• Contains vocal cords

The trachea ...

• Air tube from larynx to bronchi

• Held open by C-shaped cartilaginous rings

• Contains cilia projecting from epithelium

• Cilia keep lungs clean by sweeping debris toward throat.

• Mucus secreted to embed and transport debris.

• If blocked … tracheotomy may be performed.

The Bronchi ...

• Trachea divide into two bronchi (sing. Bronchus)

• Cartilage rings keep tube open

• Lead to right and left lungs

• Branch into smaller units termed bronchioles.

• Asthma is constriction of bronchioles, which reduces or prevents air movement.

• Terminate in air pockets or sacs termed alveoli.

The Alveoli (a case of structure matching function)

• Functional unit of the lungs since this is where gas exchange actually occurs.

• Single layer of squamous epithelium surrounded by blood capillaries.

• Approximately 300 million alveoli have total cross-sectional area of 50-70 m2 …

• This is about 40 times the surface area of the skin.

• I.R.D.S. (lack of lipoprotein surfactant)

The Diaphragm and Ribs

• Diaphragm is a layer of dome shaped muscle that makes up the base of the thoracic cavity.

• Functions to increase size of thoracic cavity thereby decreasing pressure, when it contracts.

• The ribs, hinged to the vertebral column at the back and the sternum at the front, make up the top and sides of the thoracic cavity.

• Very much a part of the breathing process.

The Pleural Membranes

• The lungs are covered by the pleural membranes, one of which covers the lungs themselves, and the other that lines the chest cavity.

• Function is to hold lungs to thoracic wall which creates a seal to reduce pressure in the lungs.

• Inflammation is called pleurisy.

•The pleural cavity in certain conditions may be filled with air (pneumothorax), blood (hemothorax), or pus.

•Any opening of the wall, whether done for surgical purposes or by accident from a bullet or knife wound, will cause the lungs to collapse due to the pneumothorax created.

The Breathing Mechanism ...

• Could you describe the interaction of lungs, pleural membranes, ribs, and diaphragm during inhalation and exhalation?