Breathing – the movement of air into and out of the lungs
External Respiration- the exchange of O an2 CO betw2en AIR and BLOOD
Internal Respiration- the exchange of O an2 CO betw2en BLOOD and TISSUE FLUID
Cellular Respiration- the process of which produce ATP in mitochondria requires O and re2eases CO 2
Breathing: Bringing air to the Lungs
-Inspiration –breathing air in
-Expiration- breathing air out
1. Air enters the nasal passages.
-hairs and CILIA trap dust and debris
-the air is warmed and moistened.
2. The warmed and moistened air passes through the PHARYNX (a common passage for food and air).
-the nose itself contains two nasal cavities (narrow canals with convoluted lateral walls that are
separated from one another by a SEPTUM).
- The nasal cavities are connected by tubes to the tear ducts and to the ears via the EUSTACHIAN
-When we breathe, the GLOTTIS (the opening to the LARYNX ("voice box")) is open, and when we
swallow, the EPIGLOTTIS covers the glottis.
3. The air enters the larynx.
-Elastic ligaments called VOCAL CORDS stretch from the back to the front of the larynx just at the
sides of the glottis.
-These cords vibrate when air is expelled past them through the glottis.
-The pitch of the voice depends on the length, thickness, and degree of elasticity of the vocal cords
and the tension at which they are held.
-Muscles adjust the tension of the chords to produce different sounds.
4. The air enters the TRACHEA (windpipe). The trachea is held open by cartilaginous rings, and is lined
with ciliated mucous membranes.
-The cilia beat upward to move up mucus and any dust or particles that were inhaled or accidentally
swallowed. Smoking can destroy cilia. -Tracheostomy: an operation in which an incision is made into the trachea below a blockage (and a
tube is then inserted).
5. The trachea divides into two BRONCHI, which branch into many smaller passages called bronchioles
that extend into the lungs.
6. The bronchioles continue to branch out, and as they do, their walls get thinner and diameter smaller.
Each bronchiole ends in sacs called ALVEOLI, which fill up much of the lungs.
-each alveolar sac (an air sac from the lung tissue) is combined by a single layer of simple squamous
-surrounded by capillaries
-carries deoxygenated blood
-gas exchanges occur between blood and air in the alveoli (mini sac in the lungs)
-lined with a strip of lipoprotein to prevent them to collapse when air leaves
-breathing is powered by the DIAPHRAGM
-lungs are enclosed by two pleural membranes
-one lines the chest walls and inner membranes line the lung
-Intercostal muscle (muscle attached to the ribs) contracts when you inhale
-contraction pulls the ribs in and out