1. Respiratory System Normal breathing rate 14-20 breaths/min
Average person uses about .25 liters of oxygen/min
Lungs hold about 4-6 liters of air
Oxygen is needed to metabolize glucose and release water and carbon dioxide

2. Respiration
3 Components of Respiration Breathing  entrance/exit of air to/from lungs 2a. External respiration  movement of air to blood 2b. Internal respiration  movement of blood/oxygen to tissue Aerobic cellular respiration  production of ATP in cells from metabolism of glucose

3. Respiratory Structures
Description
Function
Nasal Cavity
Hollow space in nose
Filters and warms air
Pharynx
Chamber behind oral cavity
Connection to surrounding regions
Glottis
Opening to larynx
Passes air into larynx
Larynx
Vocal chords
Sound production
Trachea
Tube that connects larynx with bronchi
Passage of air to bronchi
Bronchi
Major divisions that
enter lungs
Passage of air to each lung
Bronchioles
Small branched tubes that lead to alveoli
Passage of air to
alveoli
Lungs
Organs that occupy thoracic cavity
Gas exchange

4. Lungs Right lung has 3 lobes; left lung has 2 lobes
Lie at either side of the heart
Base of the lung is broad and concave to fit into the convex diaphragm
Approximately 300 million alveoli in lungs
Alveoli increase the surface area of the lung so more oxygen can be taken up
Alveoli are bathed in surfactant, which reduces their surface tension and
prevents collapse
Gas filled alveoli are very light; a piece of lung usually floats on water
Ear Lobes
3 lobes 
<---2 lobes

5. Alveoli with attached arterioles and venules (Capillaries)

6. The Anatomy of Breathing
During ventilation, there is continuous air flow from pharynx to alveoli
The rib cage forms the top and sides of the thoracic cavity The diaphragm forms the bottom of the thoracic cavity
The outer pleural membrane is attached to the rib cage and diaphragm

7. The Physiology of Breathing
Inspiration
Respiratory center is located in the medulla oblongata
Neurons in the RC fire automatically in a rhythmic cycle
Carbon dioxide levels in blood, lungs, or brain can cause changes in the activity of the RC
When carbon dioxide levels rise, receptors in body send message to MO to increase the firing of respiratory neurons
MO sends impulses directly to the diaphragm and rib muscles
In relaxed state the, diaphragm is dome shaped.
When excited by the MO, the dome falls, intercostal muscles contract, pushing the rib cage out
These actions create a vacuum of negative space in the lungs, the volume of the lungs increases, and air rushes in
Humans inhale by negative pressure
Deep inspiration excites stretch receptors in alveoli, which in turn send a message in MO to stop inhalation

8. The Physiology of Breathing
Expiration
Diaphragm and rib muscles relax and push upward and inward on the lungs
Deep expiration excites stretch receptors in alveoli, which in turn send a message in MO to stop inhalation

9. Lung Capacity Lungs hold about 4-6 liters of air
Tidal Volume  amount of air moved in and out in 1 breath (.1-.2 liters)
Vital Capacity  Maximum amount of air taken in 1 breath (3.1 liters)
Residual Volume After all air is expelled, there is still some air in lungs (<1 liter)
Healthy Lung
Smoker’s lung

10. Internal & External Respiration
Alveoli and blood vessels both consist of a thin layer of cells
Both the alveoli and blood vessels allow for the free passage of oxygen, carbon dioxide
Diffusion ALONE governs the exchange of oxygen and carbon dioxide at the alveoli
Oxygen diffuses from the O2 rich alveoli to the O2 poor blood vessels
Carbon dioxide diffuses from the CO2 rich blood vessels to CO2 poor alveoli

11. Oxygen & Hemoglobin
Breathing at high altitude is less effective than at low altitudes because the concentration of oxygen is low, therefore less O2 diffuses into the blood
Hemoglobin tends to attach to oxygen at cooler temperatures and tends to release oxygen at warmer temperatures

12. Internal Respiration
Blood that enters the tissues is bright red because the pigment hemoglobin turns red when attached to oxygen
Oxygen diffuses out of the blood and into the tissues (at the capillaries)
Carbon dioxide diffuses from the tissue to the blood (at the capillaries)
Deoxygenated red blood cells have no oxygen; turning the RBC blue
Red blood cells also pick up carbon dioxide and deliver it to the lungs