PowerPoint to accompany

PowerPoint Lecture Outlines
to accompany
Hole’s Human
Anatomy and Physiology
Tenth Edition
Shier w Butler w Lewis
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Chapter 19
Respiratory System
Respiration is the process of exchanging gases between the
atmosphere and body cells. Consists of the following
• ventilation- air in and out of lungs
• external respiration- air and blood in lungs
• transport
• internal respiration- blood and tissue
• cellular respiration-oxygen and co2
• Nose –nares
• Nasal cavity- separated from cranial and
oral cavity- ethmoid and maxilla
• Nasal septum- ethmoid and vomer
• Meatus- superior, middle, and inferior
• Pharynx- smell, conducts air, entraps
particles, moistens, and heats air
• Cilia- moves mucus and particles toward
Larynx- vocal cord, epiglottis, and cartilages
Trachea- cartilage, muscle, and elastic
Bronchial tree- RT. And LT. main stem bronchi
Secondary- lobar – three on right and two on left
Tertiary- ten on the right and eight on the left
Interlobular- lobules
Terminal- 50 to 80 within each lobule of lung
Respiratory- 2 or 3 branch from each terminal
– Alveolar ducts----branch into sacs----Alveoli
Organs of the
Respiratory System
Upper Respiratory Tract
Mucous in Respiratory Tract
Cilia move mucus and trapped particles from the nasal cavity
to the pharynx
Trachea- bronchi-bronchioles-Ciliated Pseudocolumnar
Goblet cells secrete mucus
Air-filled spaces in maxillary, frontal, ethmoid, and
sphenoid bones Functions are to reduce the weight of the
scull and serve as resonant chambers that affect the
quality of the voice.
Upper lateral folds- false vocal cords
True vocal cords- responsible for sound
Laryngeal muscles- control pitch
Glottis and epiglottis- close during
Performed to allow air to bypass an obstruction
within the larynx
• Larynx superior to the
trachea and inferior to the
• Composed of muscles and
• Cartilage- thyroid, cricoid,
and epiglottic
• Thyroid- superior to the
thyroid gland
• Cricoid -inferior to the
thyroid gland
• Epiglottic- attached to the
upper border of the thyroid
• Anterior to the esophagus- located in the
thoracic cavity (Mediastinum)
• Trachea and bronchi supported with Cshaped hyaline cartilage.
• Posteriorly- incomplete rings contain
muscle and connective tissue
• Carina-projection of the last trachea ring,
located in the sagittal plane.( associated
with the cough reflex)
• Spits into Right and left main stem
Trachea and Bronchi
• Right main bronchus is wider, shorter and runs
more vertically than the left.
• Left main bronchus passes inferiorly to the arch of
the aorta and anterior to the esophagus.
• Lobar bronchi- secondary branches –two on the
left and three on the right.
• Tertiary bronchi-several segments that branch into
20-25 terminal bronchioles.
• Respiratory bronchioles- contain 11-alveolar ducts
and 5-6 alveolar sacs. Fully developed by age 8,
with 300 million alveoli
Cross section of trachea
Wall of trachea
Bronchial Tree
Location of Lungs
Muscles of the Thoracic Wall
• Pectoral muscles- major and minor
• Subclavius
• Serratus anterior- rotates the scapula and holds the
scapula against the thoracic wall.
• Scalene muscles- from the neck to the 1st and 2 nd
ribs, elevate ribs during forced inspiration
• Intercostal muscles- between ribs
• External intercostal muscles- muscles of inspirationelevate the ribs.
• Internal intercostals- are muscles of expiration.
• Innermost intercostals- deep, separated from internal
intercostals by nerves and vessels.
• Subcostal muscles- aid in elevation of ribs
Transverse Section of Lungs
• Co2 is stored in three forms:
– 6%- is dissolved in solution
– 8%- is bound to hemoglobin-Carbaminohemoglobin
– 90%-is dissolved in blood as bicarbonate
– CO2+H2O H2CO3HCO3 +H
– Chloride Shift-Tissue and Blood
Co2 diffuses inside a RBC forming carbonic acid.
Carbonic acid rapidly dissociates into hydrogen
and bicarbonate ions. Hydrogen binds to
deoxyhemoglobin and HCO3ˉ diffuses out of the RBC.
Chloride, which is also negatively charged, enters the
Chloride Shift
• bicarbonate ions diffuse out RBCs
• chloride ions from plasma diffuse into RBCs
• electrical balance is maintained
Carbon Dioxide Transport
• dissolved in plasma
• combined with hemoglobin
• in the form of bicarbonate ions
• Reverse-capillaries of the lungs
• Deoxyhemoglobin----Oxyhemoglobin
Hydrogen is released, combines with
bicarbonate, forming carbonic acid.
H+ + HCO3ˉ---H2CO3----CO2 + H2O
Carbon Dioxide in Lungs
Diffusion Through
Respiratory Membrane
Gases are exchanged between alveolar air and capillary
blood because of differences in partial pressure
Oxygen Transport
• Most oxygen binds to hemoglobin to form oxyhemoglobin
• Oxyhemoglobin releases oxygen in the regions of body cells
• Much oxygen is still bound to hemoglobin in the venous blood
Review Questions
• Most of the carbon dioxide is present in the blood
as bicarbonate.
• The conversion of CO2 to bicarbonate occurs
primarily within the erythrocytes.
• In the lung, the reaction is determined by carbon
dioxide relative to bicarbonate ion concentration.
• Chloride is transported into the RBC at the same
time bicarbonate moves out. The H released from
carbonic acid binds to hemoglobin. The increase
in the affinity of hemoglobin for CO2 corresponds
to a lowered O2.
• Two Types of alveolar cells
– Type I- 95%-gas exchange
– Type II- Secrete surfactant and reabsorb Na and
PressuresAtmospheric pressure at sea level 760mmHg or
760 torr
Dalton’s Law, the total pressure of a gas mixture
is equal to the sum of the pressures that each
gas in the mixture would exert independently.
Partial pressure of a particular gas- is equal to the
product of the total pressure and the fraction of
that gas in the mixture.
Normal Breathing
• Breathing rhythm involves the medulla and
the pons.
– Inspiratory and expiratory neurons
– Inspiration- action potential travels via the
phrenic nerves motor neurons are activated and
contraction of diaphragm and external
intercostals occurs. As the stimuli increases
other respiratory muscles contract, increasing
the volume of the lung. Quiet breathing means
passive relaxation of the muscles. Then the next
breathing cycle is initiated.
• Oxygen- 21% of the atmosphere-.21 (760
-47) = 150mmHg
• Henry’s law-Since solubility is a constant
and the temperature of blood does not vary,
the concentration of a gas dissolved in a
fluid depends directly on its partial pressure
in the gas mixture. Blood gases are
measured using an oxygen electrode
Expiration- Passive
• The elastic recoil of the lung reduces pressure in
the cavity, therefore increasing the intra alveolar
pressure above atmospheric pressure. Air inside
the lungs is forced out.
• During exhalation the diaphragm moves upward
and the ribs move downward.
• Forced expiration- involves contraction of the
internal intercostal and abdominal muscles.
Lungs at Rest
When lungs are at rest, the pressure on the inside of the
lungs is equal to the pressure on the outside of the thorax
Air Movements
• Moving the
plunger of a syringe
causes air to move in
or out
• Air movements in
and out of the lungs
occur in much the
same way
• Intra-alveolar
pressure decreases to
about 758mm Hg as
the thoracic cavity
• Atmospheric
pressure forces air
into the airways
Maximal Inspiration
Thorax at end of
normal inspiration
Thorax at end of maximal inspiration
• aided by contraction of
sternocleidomastoid and pectoralis minor
• due to elastic recoil of the lung tissues and abdominal organs
Maximal Expiration
• contraction of
abdominal wall
• contraction of
posterior internal
intercostal muscles
Respiratory Volumes
•TV- tidal volume – volume moved in or out during a
normal breath
•IRV- inspiratory reserve volume – volume that can be
inhaled during forced breathing in addition to tidal
• ERV-expiratory reserve volume – volume that can be
exhaled during forced breathing in addition to tidal
• RV-residual volume – volume that remains in lungs at all
• FRV-functional residual capacity = ERV + RV
• IC-inspiratory capacity = TV + IRV
• VC-vital capacity = TV + IRV + ERV
• TLC-total lung capacity = VC + RV
• Imagine a TV set in a house the width of the house
represents the difference in the volume of the lung
between maximum inspiration and maximum
expiration. On either side of the TV are Irvine and
Erving. The get tired of the TV, so they go outside
to use their RV. The weather is cold and icy, and
they get into an accident, leading them to crash
into their own house, whereupon they mutter
“This frickin’ice”(FRC,IC).
They are admitted to the hospital where they have
their vital signs taken. They recover with TLC.
Respiratory Volumes and Capacities
Alveolar Ventilation
minute ventilation
• tidal volume
multiplied by
breathing rate
• amount of air that is
moved into the
alveolar ventilation rate
• major factor affecting
concentrations of oxygen
and carbon dioxide in the
• volume of air that
reaches alveoli
• tidal volume minus
physiologic dead space
then multiplied by
breathing rate
Factors that influence the rate of
• Pons and medulla regulate breathing
• CO2 levels establishes the rate of breathing
• Mechanoreceptor reflexes respond to changes
in the volume of the lungs and arterial blood
• An elevated body temperature will increase
• Chemoreceptor respond to changes in the
oxygen and carbon dioxide of the blood and
CSF. (eg. Decrease O2 : increase ventilation)
– Carotid and aortic arch-
Review Questions
• Pneumotaxic center- stimulatory effect on
• An increase in CO2 will increase the
concentration of H+ in the RBC, which will
decrease the pH of the blood.
• A 10% increase in arterial CO2- will
increase the rate of breathing
• Carbon dioxide- most is transported as
bicarbonate ions
• Oxygen is transported by hemoglobin
Respiratory Center
Respiratory Center
Factors Affecting Breathing
Decreased blood
oxygen concentration
stimulates peripheral
chemoreceptors in the
carotid and aortic
Factors Affecting Breathing
• motor impulses travel from the
respiratory center to the
diaphragm and external
intercostal muscles
• contraction of these muscles
causes lungs to expand
• expansion stimulates stretch
receptors in the lungs
• inhibitory impulses from
receptors to respiratory center
prevent overinflation of lungs
Factors Affecting Breathing
• high blood PCO and high CSF H+
concentrations stimulate chemoreceptors
of the respiratory center
• alveolar ventilation increases
• CO2 levels decrease in blood
• H+ decrease in CSF
Respiratory Membrane
• consists of the walls of the alveolus and the capillary
Diffusion Across Respiratory
Respiratory Infections
• Most common cause of respiratory tract infection-Viruses
– Self-limiting or life threatening
– Lead to secondary bacterial infections
Common Cold- most common cause- Rhinovirus
Portal of entry- hands, nasal mucosa and conjunctivae of
the eye
Influenza-Upper and lower respiratory- Influenza A or Bflu like symptoms – If the virus is contained in droplets,
it can bypass the upper respiratory tract and establish in
the lungs resulting in pneumonia.
-Epidemic or pandemic
Immunization- Given to individual at high risk new
strains appear against which the person lacks immunity.
• Pneumonias- lower respiratory- Inflammation of lung
tissues- alveoli and bronchioles
• Lobar Pneumonia- Acute-occurs in healthy adults most
commonly caused by Streptococcus pneumoniae involving
an entire lobe.
– Rapid onset, chill, high fever, and malaise Congestion,
cough, watery sputum, and fine crackles can be heard
during breath sounds.
Legionnaires- Legionella pneumophila, found in warm
standing water.
Respiratory and CNS symptoms- leading to fatal
Atypical pneumonia- acute inflammatory changes
Most common cause- Mycoplasma pneumonia
Lower respiratory disorders
• Pneumothorax- When air from the airways enter the
pleural cavity causing collapse of the affected lung results
– Spontaneous or result of direct injury to the chest.
– Pleural Effusion- refers to a collection of fluid in the
pleural cavity.
• Clear, pus or blood
• Hydrothorax- noninflammatory serous fluid most
common cause is CHF
• Hemothorax- presence of blood- 300ml-500ml
– Complication of surgery, cancer, rupture of the
aorta or injury
Lower Reparatory
• Atelectasis- refers to the incomplete expansion of
a lung due to airway obstruction and lung
compression. Breathing high concentration of
oxygen, such as while on a ventilator, increases
the rate which gases is are absorbed from the
• Pulmonary embolism- bloodborne substance
lodges in a branch of the pulmonary artery and
obstructs the flow.
– Most common cause is due to a deep vein thrombosis
– Thrombus, air, fat from the bone marrow after a
fracture, or amniotic fluid.
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