1. Presentation title slide

2. UNIT B: Human Body Systems
Chapter 8: Human Organization
Chapter 9: Digestive System
Chapter 10: Circulatory System and Lymphatic System
Chapter 11: Respiratory System:
Section 11.2
Chapter 12: Nervous System
Chapter 13: Urinary System
Chapter 14: Reproductive System

3. Chapter 11: Respiratory System
UNIT B
Chapter 11: Respiratory System
Chapter 11: Respiratory System
In this chapter, you will learn about the structure and function of the respiratory system.
How would a narrowing and swelling of the airways affect the respiratory volumes?
How do the typical treatments for asthma work to reduce the symptoms?
Why is it so difficult to develop a cure for asthma?
What are some of the normal defence mechanisms of the respiratory tract?
Asthma is a disease in which the airways become constricted (narrowed) and inflamed (swollen), both of which can result in difficulty breathing. It is one of the most common chronic diseases in children. It is estimated that 10 to 15 percent of children in Canada have asthma.
Chapter opener figure background:
The incidence of asthma seems to be increasing rapidly. One hypothesis is that we may be “too clean,” in the sense that as children we are not exposed to enough common bacteria, viruses, and even worm parasites. As a result, our immune system may react to harmless material we inhale. Living next to a highway may be another significant factor. There are many harmful forms of air pollution, but scientists are becoming increasingly concerned about tiny “ultrafine” particles, which are produced at high levels by diesel engines. At no more than 0.1 micrometre (μm) across, these particles can bypass the normal defences of the upper respiratory tract and end up lodging deep in the lungs, with damaging effects.
TO PREVIOUS SLIDE

4. 11.2 Mechanism of Breathing
UNIT B
Chapter 11: Respiratory System
Section 11.2
11.2 Mechanism of Breathing
A free flow of air is vitally important during ventilation (breathing).
A spirometer is a device used to record the volume of air inhaled and exhaled with each breath.
TO PREVIOUS SLIDE

5. UNIT B Chapter 11: Respiratory System Section 11.2
Figure 11.7 Measuring ventilation. A spirometer measures the air inhaled and exhaled with each breath. During inspiration, the pen moves up. During expiration, the pen moves down. Vital capacity (red) is the maximum amount of air a person can exhale after taking the deepest inhalation possible.
TO PREVIOUS SLIDE

6. Respiratory Volumes UNIT B
Chapter 11: Respiratory System
Section 11.2
Respiratory Volumes
Tidal volume: the amount of air that is inhaled and exhaled at rest
TO PREVIOUS SLIDE

7. UNIT B
Chapter 11: Respiratory System
Section 11.2
Inspiratory reserve volume: the additional volume of air that can be inhaled beyond the tidal volume (e.g., during deep breathing)
Expiratory reserve volume: the addition volume of air that can be exhaled beyond the tidal volume
TO PREVIOUS SLIDE

8. UNIT B
Chapter 11: Respiratory System
Section 11.2
Vital capacity: the maximum volume of air that can moved in and out during a single breath
Vital capacity = tidal + inspiratory reserve + expiratory reserve
TO PREVIOUS SLIDE

9. UNIT B
Chapter 11: Respiratory System
Section 11.2
Residual volume: amount of air that remains in the lungs and airways after a full exhalation
During normal breathing, only 70% of tidal volume reaches the alveoli; about 30% remains in the airways. This air is not useful for gas exchange because it has been depleted of oxygen.
TO PREVIOUS SLIDE

10. Respiratory volumes depend on various factors.
UNIT B
Chapter 11: Respiratory System
Section 11.2
Respiratory volumes depend on various factors.
Age (decreasing after age 30)
Gender (10-20% lower in women)
Physical activity (20-30% higher in conditioned athletes)
Respiratory disorders
Some disorders decrease vital capacity or can increase residual volumes because the individual has difficulty emptying the lungs
TO PREVIOUS SLIDE

11. Inspiration and Expiration
UNIT B
Chapter 11: Respiratory System
Section 11.2
Inspiration and Expiration
To understand ventilation, the following facts should be remembered:
There is a continuous column of air from the pharynx to the alveoli in the lungs.
The lungs lie within the sealed-off thoracic cavity.
Rib cage: top and sides of the thoracic cavity
Intercostal muscles: lie between the ribs
Diaphragm and connective tissue: floor of the thoracic cavity
The lungs adhere to the thoracic wall through the pleura.
Space between the two pleurae is minimal due to surface tension of the fluid between them
TO PREVIOUS SLIDE

12. Inspiration UNIT B Inspiration is the active phase of ventilation.
Chapter 11: Respiratory System
Section 11.2
Inspiration
Inspiration is the active phase of ventilation.
Diaphragm: contracts and lowers
Intercostal muscles: contract
Rib cage: moves up and out
As the thoracic volume increases, the lung volume increases, and air pressure in alveoli decreases
Alveolar pressure is lower than atmospheric pressure outside lungs, causing air to flow into airways
inspiration: the active phase of ventilation in which the diaphragm and the external intercostal muscles contract
TO PREVIOUS SLIDE

13. Expiration UNIT B Expiration is the passive phase of ventilation.
Chapter 11: Respiratory System
Section 11.2
Expiration
Expiration is the passive phase of ventilation.
Diaphragm: relaxes and moves up
Intercostal muscles: relax
Rib cage: moves down and in
As the thoracic volume decreases, the lung volume decreases, and air pressure in alveoli increases
Alveolar pressure is higher than atmospheric pressure outside lungs, causing air to be pushed out
expiration: passive phase of breathing in which air is expelled from the body
TO PREVIOUS SLIDE

14. UNIT B Chapter 11: Respiratory System Section 11.2
Figure 11.8 Inspiration and expiration compared. a. During inspiration, the thoracic cavity and lungs expand so that air is drawn in. b. During expiration, the thoracic cavity and lungs resume their original positions and pressures. Now, air is forced out.
TO PREVIOUS SLIDE

15. Control of Breathing UNIT B
Chapter 11: Respiratory System
Section 11.2
Control of Breathing
Ventilation is controlled by a respiratory centre in the medulla oblongata of the brain.
Stimulates inspiration by automatically sending impulses to the diaphragm through the phrenic nerve, and to the intercostal muscles through the intercostal nerve
respiratory centre: located in the medulla oblongata of the brain; controls the rhythm of ventilation
Figure 11.9 Nervous control of breathing. The respiratory centre automatically stimulates the external intercostal (rib) muscles and diaphragm to contract via the phrenic nerve. After forced inhalation, stretch receptors send inhibitory nerve impulses to the respiratory centre via the vagus nerve. Usually, expiration automatically occurs because of the lack of stimulation from the respiratory centre to the diaphragm and intercostal muscles.
TO PREVIOUS SLIDE

16. Control of Breathing UNIT B
Chapter 11: Respiratory System
Section 11.2
Control of Breathing
When the respiratory centre stops sending signals to the diaphragm and rib cage, the diaphragm relaxes and expiration occurs
Following inhalation, stretch receptors in the alveolar walls send inhibitory nerve impulses via the vagus nerve to the respiratory centre, which inhibits the respiratory centre from sending impulses
TO PREVIOUS SLIDE

17. Control of Breathing UNIT B Chemical Input
Chapter 11: Respiratory System
Section 11.2
Control of Breathing
Chemical Input
The respiratory centre is also sensitive to levels of carbon dioxide and hydrogen ions in the blood
When carbon dioxide or hydrogen ion concentrations increase, the respiratory centre increases rate and depth of breathing
Respiration rate is also influenced by cells called carotid bodies and aortic bodies
When concentration of blood oxygen decreases, these bodies signal the respiratory centre to increase rate and depth of breathing
carotid bodes: a group of cells located in the carotid arteries that are sensitive to blood oxygen levels and influence respiration rate
aortic bodies: a group of cells located in the aorta that are sensitive to blood oxygen levels and influence respiration rate
TO PREVIOUS SLIDE

18. Check Your Progress UNIT B Compare tidal volume and vital capacity.
Chapter 11: Respiratory System
Section 11.2
Check Your Progress
Compare tidal volume and vital capacity.
Explain why inspiration is considered the active phase of ventilation, and expiration the passive phase.
ANSWERS
1. Tidal volume is the amount of air that normally moves in and out of the lungs with each breath; vital capacity is the maximum volume of air that can be moved in and out of the lungs in a single breath.
2. Inspiration is considered the active phase of respiration because it requires the contraction of the diaphragm and external intercostal muscles in order to create the low pressure in the lungs.
Expiration is the passive phase because it requires no muscle contractions, just elastic recoil of the thoracic wall and lungs.
TO PREVIOUS SLIDE

19. UNIT B
Chapter 11: Respiratory System
Section 11.2
TO PREVIOUS SLIDE

20. UNIT B
Chapter 11: Respiratory System
Section 11.2
TO PREVIOUS SLIDE