Respiratory system

Why do animals need a respiratory system??

• We need to get oxygen to each and every cell in the body!

• We need to get carbon dioxide carried away from the cells and away from the body!

• Why do we need to transport these gases?

• What is oxygen used for?

• Why is carbon dioxide produced?

• Why is it a ‘waste’ material?

• Remember that oxygen is needed for ‘cellular respiration’. In the cell’s mitochondria, glucose is broken down to provide our energy needs.

• carbon dioxide is the waste gas produced.

cellular respiration

• glucose + oxygen = carbon dioxide + water + energy

Let’s look at the anatomy!

What goes on in the head region???

What are the advantages of sending the air through the nasal

passages?

• Be prepared to list the functions of sending the inhaled air through the nasal passages:

• The air is filtered!

• The air is moistened!

• The air is warmed!

• We get a chance to smell (olfaction)

Mouth region:

Vocal chords:

swallowing:

Trachea and bronchi:

• Can you describe some structural features of these passageways that allow them to be very effective?

Alveoli:

• Can you describe some structural features of the alveoli that allow them to be very effective?

Control of breathing:

• How often do we breathe?

• What affects our breathing rate?

• Where is the control centre?

• What parameters are monitored in the body to set the rate of breathing?

• Control centre is in brainstem

• The structure is called the medulla oblongata

• The brain continuously monitors blood levels for Co2, O2 and pH and adjusts breathing accordingly

Mechanics of breathing:

• What anatomical structures are involved in the process of breathing?

• passageways

• alveoli

• diaphragm

• rib muscles

Mechanics of breathing

• control centre is in brainstem• inspiratory signal triggers diaphragm and rib

muscles to contract• diaphragm flattens and ribs lift up and out• this increases volume of chest (thoracic) cavity• as a result the pressure in chest cavity drops• as a result air rushes in (inhalation)• in restful breathing exhalation is passive (recoil

of muscles).

Lung volumes and capacities:

Lung volumes/capacities

• Tidal volume

• Inspiratory reserve volume

• Expiratory reserve volume

• -----------------------------------------

• The above add up to the vital capacity

Lung disease:

• Can you name some diseases involving the lungs?

• Bronchitis• Emphysema• Pneumonia• Lung cancer• Tuberculosis• Asthma• Influenza• Others?

Summary points

• know the anatomy!• nasal passages: air is warmed, filtered and

humidified (olfaction as well)• role of epiglottis• role of larynx/voice box• adaptations of trachea and bronchiole passages:

cartilage rings, mucous, cilia, smooth muscle• adaptations of alveoli: thin, great surface area,

rich blood supply,