Transcript Chapt09 Lecture 13ed Pt 3

Human Biology
Sylvia S. Mader
Michael Windelspecht
Chapter 9
Respiratory
System
Lecture Outline
Part 3
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
1
9.5 Control of Ventilation
How is breathing controlled by
the nervous system?
• Nervous control
– Respiratory control center in the brain
(___________________) sends out nerve
impulses to contract muscle for inspiration.
– Sudden infant death syndrome (SIDS) is
thought to occur when this center stops
sending out nerve signals.
2
9.5 Control of Ventilation
How is breathing controlled by
the nervous system?
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
brain
Respiratory center:
region of the brain that
automatically regulates
breathing
Intercostal nerves
stimulate the intercostal
muscles to contract.
External intercostal muscles
help expand the thoracic
cavity by contracting.
Phrenic nerve
stimulates the diaphragm
to contract.
Diaphragm
helps expand the thoracic
cavity by flattening when
it contracts.
Figure 9.10 The control of breathing
by the respiratory center.
3
9.5 Control of Ventilation
How is breathing chemically
controlled?
• Chemical control
– 2 sets of _______________ sense the
drop in pH: one set is in the brain and the
other in the circulatory system.
– Both are sensitive to carbon dioxide levels
that change blood pH due to metabolism.
4
9.6 Gas Exchanges in the Body
Exchange of gases in the body
• Oxygen and carbon dioxide are exchanged.
• The exchange of gases is dependent on
diffusion.
• Partial pressure is the amount of pressure each
gas exerts (PCO2 or PO2).
• Oxygen and carbon dioxide will diffuse from the
area of higher to the area of lower partial
pressure.
5
9.6 Gas Exchanges in the Body
External respiration
• Exchange of gases between the lung alveoli
and the blood capillaries.
• PCO2 is higher in the lung capillaries than the
air, thus CO2 diffuses out of the plasma into
the lungs.
• The partial pressure pattern for O2 is just the
opposite, so O2 diffuses the red blood cells in
the lungs.
6
9.6 Gas Exchanges in the Body
External respiration
Carbon dioxide transport:
H+ + HCO3H2CO3
Oxygen transport:
Hb + O2
carbonic
anhydrase
H2O + CO2
HbO2
7
9.6 Gas Exchanges in the Body
The movement of oxygen and
carbon dioxide in the body
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
alveolus
plasma
H+ + HCO–3
External respiration
Hb H+
CO2
pulmonary
capillary
HCO–3
RBC
H2CO3
CO2
Hb O2
H2O
RBC
O2
Hb CO2
pulmonary
capillary
O2
alveolus
CO2 exits blood
CO2
a.
plasma
O2 enters blood
O2
lung
pulmonary artery
pulmonary vein
heart
tissue cells
systemic vein
systemic artery
HCO–3
H+ + HCO–3
plasma
plasma
systemic
capillary
RBC
Figure 9.11
Movement of gases
during external and
internal respiration.
CO2
O2
RBC
systemic
capillary
Hb H+ H2CO3
CO2
H2O
Hb
Internal respiration
Hb CO2
tissue
fluid
CO2 enters blood
b.
tissue
cell
tissue
cell
tissue
fluid
O2 exits blood
8
9.6 Gas Exchanges in the Body
Internal respiration
• The exchange of gases between the blood in
the capillaries outside of the lungs and the
tissue fluid.
• PO2 is higher in the capillaries than the tissue
fluid, thus O2 diffuses out of the blood into
the tissues.
9
9.6 Gas Exchanges in the Body
Internal respiration
Oxyhemoglobin gives up oxygen:
HbO2
Hb + O2
Most CO2 is carried as a bicarbonate ion:
CO2 + H2O
carbonic
anhydrase
H2CO3
H+ + HCO3-
10
9.7 Respiration and Health
Upper respiratory tract
infections
• __________ – blockage of sinuses
• __________ – infection of the middle ear
• Tonsillitis – inflammation of the tonsils
• Laryngitis – infection of the larynx that leads
to loss of voice
11
9.7 Respiration and Health
Lower respiratory tract disorders
• __________ – infection of the lungs with thick,
fluid build up
• __________ – bacterial infection that leads to
tubercles (collections of encapsulated bacteria)
• Pulmonary fibrosis – lungs lose elasticity
because fibrous connective tissue builds up in
the lungs, usually because of _______________
12
9.7 Respiration and Health
Lower respiratory tract disorders
• _____________ – chronic, incurable disorder in
which alveoli are damaged, and thus the surface
area for gas exchange is reduced
• Asthma – bronchial tree becomes irritated
causing breathlessness, wheezing, and
coughing
• Lung cancer – uncontrolled cell division in the
lungs that is often caused by smoking and can
lead to death
13
9.7 Respiration and Health
Some Diseases and Disorders
of the Respiratory System
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
mucus
Pneumonia
Alveoli fill with pus and fluid,
making gas exchange difficult.
Bronchitis
Airways are inflamed due
to infection (a cute) or due to
an irritant (chronic). Coughing
brings up mucus and pus.
asbestos
body
tubercle
Pulmonary Fibrosis
Fibrous connective tissue
builds up in lungs, reducing
their elasticity.
Pulmonary Tuberculosis
Tubercles encapsulate
bacteria, and elasticity of
lungs is reduced.
Emphysema
Alveoli burst and fuse into
enlarged air spaces. Surface area
for gas exchange is reduced.
Figure 9.12 Some diseases and disorders of the respiratory system.
Asthma
Airways are inflamed due
to irritation, and bronchioles
constrict due to muscle spasms.
14
9.7 Respiration and Health
Things you should know about
tobacco and health
• All forms of tobacco can cause damage.
• Smoking increases a person’s chance of lung,
mouth, larynx, esophagus, bladder, kidney,
pancreatic, stomach, and cervix cancers.
• Smoking also increases the chance of chronic
bronchitis, emphysema, heart disease, stillbirths,
and harm to an unborn child.
• Passive smoke can increase a nonsmoker’s
chance of pneumonia, bronchitis, and lung cancer.
15