Download Chapter 11: Respiratory System

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 11.3
Chapter 12: Nervous System
Chapter 13: Urinary System
Chapter 14: Reproductive 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?
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.
TO PREVIOUS
SLIDE
Why is it so difficult to develop a cure for
asthma?
What are some of the normal defence
mechanisms of the respiratory tract?
UNIT B Chapter 11: Respiratory System
Section 11.3
11.3 Gas Exchanges in the Body
Respiration includes external respiration and internal
respiration.
• External respiration: exchange of gases in the lungs
• Internal respiration: exchange of gases in the tissues
Most of the oxygen carried in the blood is attached to the
heme portion of hemoglobin (Hb), a protein found in red
blood cells.
TO PREVIOUS
SLIDE
UNIT B Chapter 11: Respiratory System
Figure 11.10 External and Internal
respiration. During external respiration
in the lungs, carbon dioxide (CO2) leaves
the blood, and oxygen (O2) enters the
blood. During internal respiration in the
tissues, oxygen leaves the blood, and
carbon dioxide enters the blood.
TO PREVIOUS
SLIDE
Section 11.3
UNIT B Chapter 11: Respiratory System
Section 11.3
External Respiration
External respiration is the exchange of gases between air in the
alveoli and blood in the pulmonary capillaries. CO2 leaves the blood
and O2 enters the blood.
• Blood in the pulmonary capillaries has a higher partial pressure of
CO2 (PCO2) than atmospheric air
o CO2 diffuses out of the plasma into the lungs
o CO2 is carried in the plasma as bicarbonate ions (HCO3-)
o As CO2 diffuses out of the plasma, carbonic anhydrase speeds
up the breakdown of carbonic acid (H2CO3), driving the
reaction to the right:
TO PREVIOUS
SLIDE
UNIT B Chapter 11: Respiratory System
CO2 Exits the Blood
TO PREVIOUS
SLIDE
Section 11.3
UNIT B Chapter 11: Respiratory System
Section 11.3
• Blood returning from the systemic capillaries has a lower partial
pressure of O2 (PO2) than the air in the alveoli
o O2 diffuses into plasma and then into red blood cells
o Hemoglobin has a higher affinity for O2 at lower temperatures
and higher pH
o Hemoglobin takes up O2 and becomes oxyhemoglobin (HbO2)
TO PREVIOUS
SLIDE
UNIT B Chapter 11: Respiratory System
O2 Enters the Blood
TO PREVIOUS
SLIDE
Section 11.3
UNIT B Chapter 11: Respiratory System
Section 11.3
Figure 11.10 External respiration. During external respiration in the lungs, carbon
dioxide (CO2) leaves the blood, and oxygen (O2) enters the blood.
TO PREVIOUS
SLIDE
UNIT B Chapter 11: Respiratory System
Section 11.3
Internal Respiration
Internal respiration is the exchange of gases between the blood in
systemic capillaries and the tissue fluid. In internal respiration, O2
leaves the blood, and CO2 enters the blood.
• Tissues have a higher temperature and lower pH, and the partial
pressure of O2 (PO2) in tissue fluid is lower than in blood
o Therefore, oxyhemoglobin gives up O2, which diffuses out of
the blood into the tissues:
TO PREVIOUS
SLIDE
UNIT B Chapter 11: Respiratory System
Section 11.3
O2 Exits the Blood
TO PREVIOUS
SLIDE
UNIT B Chapter 11: Respiratory System
Section 11.3
• CO2 diffuses into the blood from the tissues because the PCO2 of
tissue fluid is higher than in blood
o After CO2 diffuses into the blood, it enters red blood cells
where about 10% is taken up by hemoglobin, forming
carbaminohemoglobin (HbCO2)
o The remaining CO2 combines with water in the plasma,
forming carbonic acid (H2CO3), which dissociates into
hydrogen ions (H+) and bicarbonate ions (HCO3-).
o The increased concentration of CO2 in the blood drives the
reaction to the right:
TO PREVIOUS
SLIDE
UNIT B Chapter 11: Respiratory System
Section 11.3
o The globin portion of hemoglobin combines with excess H+ to
become reduced hemoglobin (HHb)
− Blood that leaves the systemic capillaries is dark maroon
because red blood cells contain reduced hemoglobin
o When blood reaches the lungs, CO2 readily diffuses out of the
blood and is exhaled
− Carbon monoxide (CO) poisoning occurs because it has a
greater affinity for hemoglobin than O2
− CO stays combined to hemoglobin for hours, making
hemoglobin unavailable to O2 transport
TO PREVIOUS
SLIDE
UNIT B Chapter 11: Respiratory System
CO2 Enters the Blood
TO PREVIOUS
SLIDE
Section 11.3
UNIT B Chapter 11: Respiratory System
Section 11.3
Figure 11.10 Internal respiration. During internal respiration in the tissues, oxygen
leaves the blood, and carbon dioxide enters the blood.
TO PREVIOUS
SLIDE
UNIT B Chapter 11: Respiratory System
Section 11.3
Check Your Progress
1. Explain the role of hemoglobin.
2. Discuss why arterial blood is bright red in colour, but
venous blood is darker. This being the case, why does
blood oozing from a cut always appear to be bright red?
3. Explain why carbon monoxide poisoning can be rapidly
fatal.
TO PREVIOUS
SLIDE
UNIT B Chapter 11: Respiratory System
TO PREVIOUS
SLIDE
Section 11.3
UNIT B Chapter 11: Respiratory System
TO PREVIOUS
SLIDE
Section 11.3