Transcript Memmler`s The Human Body in Health and Disease 11th edition

Memmler’s
Structure and Function of the Human Body
9th edition
Chapter 16
The Respiratory System
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Phases of Respiration
Process of obtaining oxygen from environment and
delivering it to cells
• Pulmonary ventilation
• External exchange of gases
• Internal exchange of gases
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Overview of respiration.
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Checkpoint 16-1: What are the three phases
of respiration?
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The Respiratory System
Conducts air into lungs
• Nasal cavities
• Pharynx
• Larynx
• Trachea (windpipe)
• Bronchi
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The respiratory
system. (A)
Overview. (B)
Enlarged section of
lung tissue showing
the relationship
between the alveoli
(air sacs) of the
lungs and the blood
capillaries. (C) A
transverse section
through the lungs.
Zooming In: What
organ is located in
the medial
depression of the
left lung?
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Question:
True or False?: The two gases involved in
the external exchange of gases that takes
place in the respiratory system are CO2
and O2.
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Answer:
True: The two gases involved in the
external exchange of gases that takes
place in the respiratory system are CO2
and O2.
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The Nasal Cavities
• Nostrils (nares)
• Nasal cavities
– Mucous membrane
• Filters foreign bodies
• Warms air
• Moistens air
– Conchae
• Nasal septum
• Sinuses
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Checkpoint 16-2: What happens to air as it
passes over the nasal mucosa?
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The Pharynx
Throat (pharynx) carries air to respiratory tract and food
to digestive system
• Nasopharynx
– Superior portion
• Oropharynx
– Middle portion
• Laryngeal pharynx
– Inferior portion
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The Larynx
Larynx (voice box) is located between the pharynx
and trachea
• Cartilage framework
– Thyroid cartilage (Adam’s apple)
• Vocal folds (vocal cords)
– Used for speech
• Glottis
• Epiglottis
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The larynx.
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The vocal cords, superior view.
ZOOMING IN • What cartilage is named for its position above the
glottis?
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The Trachea
Trachea (wind pipe) conducts air between larynx and
lungs
• Framework of separate cartilages
• Horseshoe shaped
• Open at back for expansion during swallowing
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Checkpoint 16-3: What are the scientific
names for the throat, voice box, and windpipe?
Checkpoint 16-4: What are the three regions
of the pharynx?
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The Bronchi
• Trachea divides into two primary bronchi that enter
• the lungs
• Hilum
• Epithelial tissue lining
– Pseudostratified
– Cilia
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Microscopic view of ciliated epithelium.
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Checkpoint 16-5: The cells that line the
respiratory passageways help to keep
impurities out of the lungs. What feature of
these cells enables them to filter impurities
and move fluids?
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Question:
The air-conducting passageways of the
respiratory tract are lined with what
type of tissue?
a. stratified squamous epithelial
b. pseudostratified epithelial
c. squamous epithelial
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Answer:
b. pseudostratified epithelial
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The Lungs
• Mediastinum
• Lobes
–
Bronchial tree
–
Bronchioles
• Alveoli
• Diaphragm
• Pleura
–
Parietal pleura
–
Visceral pleura
–
Pleural space
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Lung tissue viewed through a microscope.
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Checkpoint 16-6: In what structures does
gas exchange occur in the lung?
Checkpoint 16-7: What is the name of the
membrane that encloses the lung?
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The Process of Respiration
• Ventilation of lungs
• Exchange of gases
• Transport of gases in blood
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Pulmonary Ventilation
• Inhalation (inspiration) is active phase
– Compliance
• Exhalation (expiration) is passive phase
• Lung capacity
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Pulmonary
ventilation.
(A)Inhalation.
(B)Exhalation.
Zooming In:
What muscles
are located
between the
ribs?
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Checkpoint 16-8: What are the two phases of
breathing? Which is active and which is
passive?
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Gas Exchange
• Diffusion is movement of molecules from higher to
lower concentration
• External exchange
– Gases move between alveoli and capillary blood
• Internal exchange
– Gases move between blood and tissues
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Gas exchange.
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Checkpoint 16-9: Gases move between the
alveoli and the blood by the process of
diffusion. What is the definition of diffusion?
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Transport of Oxygen
• Most oxygen in capillary blood binds to hemoglobin
• Oxygen must separate from hemoglobin to enter cells
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Checkpoint 16-10: What substance in red
blood cells carries almost all of the oxygen in
the blood?
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Transport of Carbon Dioxide
• 10% is dissolved in plasma and fluid in red blood cells
• 15% is combined with protein of hemoglobin and plasma
proteins
• 75% dissolves in blood fluids and is converted to bicarbonate
ion
– First combines with water to form carbonic acid
– Carbonic acid ionizes (separates) into hydrogen and
bicarbonate ions
– Carbonic anhydrase enzyme speeds conversion
– Buffers blood to keep pH steady
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Checkpoint 16-11: What is the main form in
which carbon dioxide is carried in the blood?
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Question:
In what structure of the respiratory
system does most gas exchange
take place?
a. bronchioles
b. pleurae
c. alveoli
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Answer:
c. alveoli
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Regulation of Respiration
Fundamental respiratory pattern
• Controlled by central nervous system centers
– Partly in medulla (main control center), partly in
pons (modifies patterns set in the medulla)
• Modified by receptors detecting changes in blood
chemistry
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Nervous Control
• Control center is located in medulla and pons of brain
stem
• Motor nerve fibers extend into spinal cord
• Fibers extend through phrenic nerve to diaphragm
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Checkpoint 16-12: What part of the brain
stem sets the basic pattern of respiration?
Checkpoint 16-13: What is the name of the
motor nerve that controls the diaphragm?
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Chemical Control
• Central chemoreceptors
– Located near medullary respiratory center
– Respond to raised CO2 level (hypercapnia)
• Peripheral chemoreceptors
– Located in neck and aortic arch
– Respond to oxygen level considerably below
normal
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Checkpoint 16-14: What gas is the main
chemical controller of respiration?
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Abnormal Ventilation
• Hyperventilation
– High oxygen level and low CO2 level (hypocapnia)
– Increases blood pH
• Hypoventilation
– Insufficient air in alveoli
– Decreases blood pH
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Breathing Patterns
• Measured in breaths per minute
• Adults: 12 to 20
• Children: 20 to 40
• Infants: more than 40
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Some Terms for Altered Breathing
• Hyperpnea
• Hypopnea
• Tachypnea
• Apnea
• Dyspnea
• Orthopnea
• Kussmaul respiration
• Cheyne-Stokes respiration
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Question:
What is the medical term for
temporary cessation of breathing?
a. dyspnea
b. apnea
c. hypopnea
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Answer:
b. apnea
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Results of Inadequate Breathing
• Cyanosis
• Hypoxia
• Hypoxemia
• Suffocation
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Age and the Respiratory Tract
• Tissues lose elasticity, become more rigid
• Decreased compliance, lung capacity
• Increased susceptibility to infection
• Increased incidence of emphysema
• Reduced capacity for exercise
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End of Presentation
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