Transcript Respiratory Ch 22-Teacher

Ch 22 The Respiration System
The Respiration System
I. Overview
A. Major Functions: Gas
Exchange & blood pH
B. 4 Processes
1. Pulmonary ventilation:
2. External respiration:
3. Transport:
4. Internal respiration:
Circulatory
system
Respiratory
system
II Functional Anatomy of the Respiratory System
Conducting Zone
C. Introduction– Major organs
• Nose, nasal cavity, and paranasal
sinuses
• Pharynx
• Larynx
• Trachea
• Lungs: Bronchi and their branches
• Lungs: respiratory bronchioles &
alveoli
= Respiratory Zone
II Anatomy-- The Conducting Zone
A. Nose
1. *Functions: take in air, warm it, and humidify it
2. External Parts
a. *External Nose
i) External Nares (nostrils)
b. Nasal Cavity (internal portion)
Nasal Bone
Cartilages
Naris (nostril)
(a) Surface anatomy
(b) External skeletal framework
Figure 22.2a
Cribriform plate
3. Internal Parts
of ethmoid bone
a) Internal Nares Sphenoid sinus
Posterior nasal
Aperture (choana)
b) Nasal Septum:
cartilage,
perpendicuoar plate, &
vomer
c) Vestibule superior to
nostrils
d) Nasal Conchae &
Meatuses: lobes and
grooves;
- function: move air
over them to warm,
clean, & moisten it
Nasal cavity
Nasal conchae
(superior, middle
and inferior)
Nasal vestibule
Nostril
Hard palate
Soft palate
3. Internal Parts
Cribriform plate
of ethmoid bone
Sphenoid sinus
Posterior nasal
Aperture (choana)
e) Walls: olfactory
mucosa (sensory
receptors) &
Respiratory mucosa
• Tissue: psuedo-…
• Goblet Cells & Cilia:
trap foreign
particles and
propell them
upward
• Lysozyme:
enzyme
• Defensins:
antibiotic
Nasal cavity
Nasal conchae
(superior, middle
and inferior)
Nasal vestibule
Nostril
Hard palate
Soft palate
f) Superior edge: Cribiform
plate
Sphenoid sinus
g) Palate = floor
• Hard: palantine process &
horizontal plate
• Soft: Muscle tissue
• Uvula
*B. Paranasal Sinuses
• *In 4 bones =
• *Functions:
Frontal sinus
C. Pharynx connects nasal cavity and mouth
to larynx and esophagus
1. Structure and composition:
skeletal muscle
*Pharyngotympanic
2. Tissue: psuedostratifiec ciliated (Eustachian) tube opening
columnar  stratified squamous
(oropharynx)
3. *Parts:
Nasopharynx
Pharyngeal T.
4. *Pharyngotympanic Tube
5. *Tonsils-- 3
Oropharynx
Palantine T.
Lingual T.
Laryngopharynx
Pharynx
D. Larynx
Epiglottis
1. Functions
a. Airway
b. Sound
Thyroid
Cricoid
2. Basic Anatomy
a. Bony Attachment
b. 9 Cartilages
• Tissue: most hyaline
i) Thyroid
• *Laryngeal Prominence
ii)
Cricoid
iii) Epiglottis
• Elastic Cartilage
• Aryepiglottic Fold
Laryngopharynx
Hyoid bone
Larynx
Epiglottis
Vocal fold
9 Laryngeal Cartilages …
iv) Arytenoid
Aryepiglottic Fold
(paired)
Cuneiform
• Vocal Cords
Corniculate
anchored to
Arytenoid
v) Corniculate
(paired)
vi) Cuneiform
(paired)
c. Vocal Folds (cords)
i)
Vocal ligaments
• Elastic fibers
ii) Glottis = vocal
folds and
opening
False Vocal
Cords
d. Epithelial Tissue– lining cavity
i) Above Vocal C. strat squamous
ii) Below Vocal C. psuedostrat …
e. Vestibular folds = false vocal cords; i)
Location: Superior and lateral to True
ii) Function: help close glottis in
swallowing
Epiglottis
Vestibular fold
(false vocal cord)
Vocal fold
(true vocal cord)
Glottis
Inner lining of trachea
Cuneiform cartilage
Corniculate cartilage
(a) Vocal folds in closed position;
closed glottis
(b) Vocal folds in open position;
open glottis
2. Basic Anatomy …
g. Intrinsic Laryngeal
Muscles (Lab only)
FUNCTION: mostly
move arytenoid
Thyroarytenoid
• Arytenoid
- On Arytenoid C.
- Oblique &
Transverse
• Cricoarytenoid
- On Cricoid C.
• Thyroarytenoid (=
vocalis)
- lateral
• Cricothyroid
- Anterior
E. Trachea = windpipe
1. Location
2. Wall composed of 3 layers
1. Mucosa: tissue =
2. Submucosa: connective t. w/ seromucous glands
3. Adventitia: outermost c.t. & encases C-shaped
cartilages
3. Hyaline Cartilage Rings
4. Trachealis muscle - connects posterior ends of C-cartilage
Function: contracts for coughing
Esophagus
Mucosa
Trachealis
muscle
Lumen of
trachea
Mucosa
Submucosa
Seromucous gland
in submucosa
Hyaline cartilage
Adventitia
Anterior
F. Bronchi and Subdivisions (bronchial tree)
CONDUCTING ZONE
1. Right and Left Primary Bronchi
• Right: wider, shorter, more vertical
• More problems
• Enter lungs at Hilium
• subdivide 23 times
2. Branching
Superior lobe
of right lung
Middle lobe
of right lung
Inferior lobe
of right lung
Superior lobe
of left lung
Left main
(primary)
Lobar
(secondary)
Segmental
(tertiary)
Inferior lobe
of left lung
a. Lobar Bronchi
(secondary): 5  5
Lobes
b.  segmental (tertiary)
bronchi
c. More Branches
d.  Bronchioles
• < 1mm
• Function: resistance
to air flow
• Terminal Bronchioles
• < 0.5 mm
• End of Conducting
Zone
• Feed into respiratory
bronchioles
Bronchial ≠ Bronchiole
F. Bronchi and subdivisions …
3. Histology Characteristics from
bronchi  bronchioles:
• Cartilage rings  plates
absent in bronchioles
• Pseudostratified columnar
ciliated columnar 
cuboidal (terminal
bronchioles)
• ↑smooth muscle (complete
ring in bronchioles)
• Elastic tissue-- all
Tracheal /Bronchial Wall
GC = Goblet Cells
GL = Gland
Cart
Plates
3. Histology …
Vein
F. Bronchi & Subdivisions
4. Respiratory Zone
= Respiratory
bronchioles, alveolar
ducts, alveolar sacs
a. alveoli
• 300 Million
i) Description
- Alveolar Duct
- Terminal cluster
of Alveoli =
Aveolar Sac .
Alveolar duct
Sac
ii) Function
Respiratory
bronchioles
Terminal
bronchiole
Respiratory
bronchiole
Alveolar
duct
Alveoli
Alveolar
sac
Alveoli
Alveolar duct
Alveolar
sac
4. Respiratory Zone …
b. Respiratory Membrane – gas  liquid
i) Alveolar & Capillary walls + basement membranes (0.5μm)
ii) Alveolar walls = simple squamous e.t. (type I cells) +
• Type II cuboidal cells secrete: surfactant +
antimicrobial proteins
(PhospholipidsRed
& blood
Proteins
cell
Nucleus of type I
(squamous
epithelial) cell
Alveolar pores
Capillary
Macrophage
O2
Capillary
CO2
Alveolus
Alveolus
Alveolar
epithelium
Fused basement
membranes of the
Respiratory alveolar epithelium
membrane and the capillary
Red blood cell
endothelium
Alveoli (gas-filled in capillary
Type II (surfactantCapillary
air spaces)
secreting) cell
endothelium
b. Respiratory Membrane …
iii) Alveolar pores = airways b/n adjacent alveoli
c. Alveolar Macrophages
d. Pulmonary Capillary Networks
d. Pulmonary Capillary Network …
Terminal bronchiole
Respiratory bronchiole
Smooth
muscle
Elastic
fibers
Alveolus
Capillaries
(a) Diagrammatic view of capillary-alveoli relationships
Figure 22.9a
II. Functional Anatomy …
G. Lungs
1. Lung Structure
• Apex, Base,
• Lobes
Lung
• Cardiac Notch
Intercostal
muscle
Rib
Parietal pleura
Pleural cavity
Visceral pleura
Trachea
• Oblique Fissure
Apex of lung
Thymus
Superior Lobe
Superior Lobe
Middle Lobe
Inferior Lobe
Inferior Lobe
Oblique Fissure
Base of lung
Cardiac notch
(a) Anterior view. The lungs flank mediastinal structures laterally.
Figure 22.10a
1. Lungs Structure …
• Root = bronchi/vascular/nerve bundle
• Hilum = site of entry
Right lung
Parietal
pleura
Visceral
pleura
Pleural
cavity
Root of lung
at hilum
• Left main bronchus
• Left pulmonary artery
• Left pulmonary vein
Left lung
Sternum
Anterior
(c) Transverse section through the thorax, viewed from above. Lungs,
pleural membranes, and major organs in the mediastinum are shown.Figure 22.10c
1. Lungs Structure …
• Bronchiopulmonary Segments
• Pyramid shaped
• Separated by connective tissue
• Served by an individual
segmental bronchus
• 8-9 per side (next slide)Oblique
• Disease often
fissure
confined to
• Lobules
• Smallest gross
Pulmonary
unit (pencil
hilum
Apex of lung
Pulmon
artery
Left m
bronch
eraser to penny
sized)
Aortic
• Served by large impression
bronchiole
• Stroma: the rest is elastic T.
Lobule
Bronchiopulmonary Segment (10 on right; 8-9 on left)
Right
superior
lobe (3
segments)
Left superior
lobe
(4 segments)
Right
middle
lobe (2
segments)
Right
inferior lobe (5 segments)
Left inferior
Figure 22.11
lobe (5 segments)
G. Lungs …
2. Blood Supply
• Pulmonary circulation
feeds alveoli – Pulmonary
arteries:
-- Pulmonary veins:
• Systemic circulation
(high pressure, low
volume)
• Bronchial arteries: to
other lung parts
• Bronchial veins
anastomose w/
pulmonary veins
• Pulmonary veins carry
most venous blood back
3. Pleaurae = double-layered serosa
• Parietal pleura on
thoracic wall,
superior face of
diaphragm
Vertebra
Posterior
• Visceral pleura on
external lung
Parietal
surface
pleura
• Pleural fluid fills
pleural cavity
Visceral
pleura
Pleural
cavity
• Function:
Provides
lubrication and
surface tension
Anterior
Figure 22.10c
III. Pulmonary Ventilation– Mechanics of
Breathing 1st Phase
A. Pressure Relationships in Thoracic Cavity
1. Basic Characteristics
• Respiratory Pressures
always relative to
Atmospheric pressure Patm =
pressure of air around
body (760mm at sea level)
• Negative respiratory
pressure value < Patm (air
sucked in)
• Positive respiratory
pressure is > Patm (air forced
out)
• Zero respiratory pressure =
Patm (no net movement)
Atmospheric pressure
1. Basic Characteristics .. ..
Atmospheric pressure
• Gases always flow
from higher pressure
to lower Pressure
2. Intrapulmonary
Pressure
But, lungs are elastic and
will collapse if not ‘held’
against thoracic wall!
760
Intrapulmonary
pressure 760 mm Hg
(0 mm Hg)
= intra-alveolar = Ppul) =
pressure in alveoli
• Fluctuates with breathing
(- sucks in; + forces out)
• Always eventually
equalizes with Patm
3. Intrapleural Pressure
Parietal pleura
Visceral pleura
Pleural cavity
= Pip = Pressure in pleural cavity
• Fluctuates with breathing
Intrapleural
pressure
756 mm Hg
(–4 mm Hg)
756
• Always negative pressure
(<Patm and <Ppul)
• 4 less than intrapulmonary
• Keeps lungs ‘sucked’ up
against chest wall
• Resists lungs recoiling power
and alveolar collapse
A. Pressure Relationships …
• If Pip = Ppul the lungs collapse
• (Ppul – Pip) = transpulmonary
pressure
• Keeps the airways open
• As chest cavity expands,
transpulmonary increases to
resist higher recoil of lungs
(4mm at resting exhalation;
6mm at resting inhalation)
Transpulmonary
pressure
760 mm Hg
–756 mm Hg
= 4 mm Hg
756
760
4. Transpulmonary pressure difference
keeps lungs against chest wall…
• Infections or
injuries can let air
into pleural cavity
= collapsed lung
(a.k.a.
atalectasis)
Pleural
Membrane
III. Mechanics of Breathing …
B. Pulmonary Ventilation– 1st Phase
• Inspiration/expiration depend on: volume changes in
thoracic cavity
• Boyle’s Law: Pressure (P) varies inversely w/ volume (V):
P1V1 = P2V2
• Increase Volume  ______________ pressure  to
equalize pressure, air must ______________
• Respiratory Cycle: One
inspiration & expiration
1. Inspiration
Passive Inhalation– muscle
actions
a. Diaphragm
• contracts: moves down
b. external intercostal
• Contract: lift rib cage
up and out.
c. lung volume: expands
2. Expiration
Passive Exhalation– muscle
actions
a. Diaphragm relaxes
moves:
b. external intercostals relax
Moves:
c. Lung volume: Rib cage
moves down & Lungs recoil
Fig. 11.7, p. 200
Inspiration
Sequence of events
Changes in anteriorposterior and superiorinferior dimensions
Changes in lateral
dimensions
(superior view)
1 Inspiratory muscles
contract (diaphragm
descends; rib cage rises).
2 Thoracic cavity volume
increases.
Ribs are elevated
and sternum flares
as external
intercostals
contract.
3 Lungs are stretched;
External
intercostals
contract.
intrapulmonary volume
increases.
4 Intrapulmonary pressure
drops (to –1 mm Hg).
5 Air (gases) flows into
lungs down its pressure
gradient until intrapulmonary
pressure is 0 (equal to
atmospheric pressure).
Diaphragm
moves inferiorly
during contraction.
Figure 22.13 (1 of 2)
Exhalation
Sequence
of events
Changes in anteriorposterior and superiorinferior dimensions
Changes in
lateral dimensions
(superior view)
1 Inspiratory muscles
relax (diaphragm rises; rib
cage descends due to
recoil of costal cartilages).
2 Thoracic cavity volume
Ribs and sternum
are depressed
as external
intercostals
relax.
decreases.
3 Elastic lungs recoil
External
intercostals
relax.
passively; intrapulmonary
volume decreases.
4 Intrapulmonary pres-
sure rises (to +1 mm Hg).
5 Air (gases) flows out of
lungs down its pressure
gradient until intrapulmonary pressure is 0.
Diaphragm
moves
superiorly
as it relaxes.
Figure 22.13 (2 of 2)
Intrapulmonary
pressure. Pressure
inside lung decreases as
lung volume increases
during inspiration;
pressure increases
during expiration.
Intrapleural pressure.
Pleural cavity pressure
becomes more negative
as chest wall expands
during inspiration.
Returns to initial value
as chest wall recoils.
Volume of breath.
During each breath, the
pressure gradients move
0.5 liter of air into and out
of the lungs.
Inspiration Expiration
Intrapulmonary
pressure
Transpulmonary
pressure
Intrapleural
pressure
Volume of breath
5 seconds elapsed
Figure 22.14
3. Forced inspiration and expiration
Forced inspiration employs pec minor,
sternocleidomastoid, erector spinae
among others to lift faster/expand further
Forced expiration is uses
abdominal and internal
intercostal muscles
C. Physical Factors Influencing Pulmonary
Ventilation
Conducting
3 factors
1. Airway resistance –
usu. low
• Increases w/:
a. inflammation +
b. smooth muscle
contraction (asthma)
• Drugs: Epinephrine
dilates bronchioles
zone
Medium-sized
bronchi
Respiratory
zone
F=ΔP/R
(remember?)
ΔP = 1-2mm
still enough flow
Terminal
bronchioles
Airway generation
(stage of branching)
C. Physical Factors affecting ventilation …
2. Alveolar Surface Tension
a. Surface tension of H2O: resists increases in surface
area
b. Surfactant (bio-soap) of Type II cells reduces surface
tension
• Prevents alveolar collapse
• Premature babies (<28 weeks) lack surfactant, require
assistance
Alveolus
Type II (surfactantsecreting) cell
Physical Factors affecting ventilation …
3. Lung Compliance
= Ability of lungs (and thoracic wall)
to stretch while under pressure.
Affects volume of air takein in
Air Volume taken in w/ given change in
transpulmonary pressure
a. Normally high, Because:
• High distensibility
• Low surface tension
b. Diminished by
• scar tissue (fibrosis)
• Reduced surfactant
• Decreased flexibility of thoracic
cage
 RESULT: More energy required
for inspiration
D. Respiratory Volumes & Pulmonary Function Tests
1. RESPIRATORY VOLUMES: Air Volumes associated with
Resp. Cycle
a) Tidal Volume (TV): normal volume in/out at rest, 500ml
• Dead Space: non-useful volume; constant = 150ml
• volume of conducting zone +
• Alveolar Dead Space: collapsed or obstructed
alveoli
Figure 13.9
b) Inspiratory Reserve Volume (IRV): extra volume
can take in past Tidal Volume, 3100ml
c) Expiratory Reserve Volume (ERV): extra volume
can exhale past Tidal volume, 1200ml
d) Residual Volume: Amount left in lungs when fully
exhale; 1200ml
• Function: prevents alveoli from collapsing
e) Vital Capacity = TV + IRV + ERV Maximum
amount that can be moved in and out; 4800ml
f) Total Lung Capacity =
TV + IRV + ERV + RV
= 6000ml
2. Average values affected by age and gender
IRV & ERV vary with gender
Measurement
Respiratory
volumes
Adult male
average value
Adult female
average value
Tidal volume (TV)
500 ml
500 ml
Inspiratory reserve
volume (IRV)
3100 ml
1900 ml
Expiratory reserve
volume (ERV)
1200 ml
700 ml
Residual volume (RV)
1200 ml
1100 ml
Copyright © 2010 Pearson Education, Inc.
Description
Amount of air inhaled or
exhaled with each breath
under resting conditions
Amount of air that can be
forcefully inhaled after a normal tidal volume inhalation
Amount of air that can be
forcefully exhaled after a normal tidal volume exhalation
Amount of air remaining in
the lungs after a forced
exhalation
Figure 22.16b
3. Pulmonary Function Tests
(OpenStax Text p. 1000)
• SPIROMETER
a. Forced Vital Capacity
b. Minute Ventilation = Tidal Volume X breaths/minute
Abnormalities
• Hyperinflation may be due to obstructive disease
• Reduced volumes result from restrictive disease
Figure 22.16a
D. Respiratory Volumes & Pulmonary Function Tests …
c. Alveolar Ventilation
= Alveolar ventilation rate (AVR): gas flow in/out of
alveoli per minute
Must use volume doing gas exchange
AVR
(ml/min)
=
frequency
(breaths/min)
X
(TV – dead space)
(ml/breath)
IV. Gas Exchange Between the Blood, Lungs,
and Tissues
(Phase 2 & 4)
A. Basic Properties of Gases
1. Total Pressure: The sum of
the pressures of each gas
• Partial Pressure of a Gas
• Proportional to gas %
and concentration
• Partial Pressures of Gases
in Atmosphere at Sea
Level
Total = 760mmHg
A. Basic Properties of Gases …
2. Gas in Contact with Liquid (Henry’s Law)
a) Gas dissolves into liquid: proportional to its partial
pressure
• Gases move from High Pressure  Low Pressure
• At equilibrium: partial pressures in gas & liquid are
equal
b) Amount of Gas in liquid also
affected by Solubility: CO2 and O2
• CO2 is 20 times more soluble in
water than O2
c) Other Factors
• Increasing Temperature
• Increasing Pressure
• Scuba Diving
Air
Water
B. Composition of Alveolar Gas
• Alveoli gas mix is slightly different from atmosphere
Because:
• Gas exchanges is occurring
• Inhaled new air mixes with residual old air
• Humidification of air
C. External Respiration– 2nd Phase
• Movement of gases from air  blood  body cells:
Simple Diffusion
Alveolar Air
Low CO2 in air; High O2
High CO2 in blood; Low O2
1. In Lungs:
Veins
leaving Body
a) O2
Cells &
• pp O2 in Alveoli = 104 Pulmonary
Arteries
• pp O2 in Pul. A. = 40
large pressure
difference
Equilibrium in 0.25 s
O2 diffuses into
(1/3 time RBC in lungs)
blood
Pulmonary
Veins &
Aorta
C.
External Respiration …
1. Lungs …
Low CO2 in air; High O2
Alveolar Air
104 40
High CO2 in blood; Low O2
b) CO2
• CO2 in Alveoli = 40
• CO2 in Pul. A. = 45
Pressure difference
lower, but solubility is
much higher
CO2 diffuses out of
blood to alveolar air
Veins
leaving Body
Cells &
Pulmonary
Arteries
40
Pulmonary
Veins &
Aorta
45
100 40
2. Ventilation-Perfusion Coupling
a) Perfusion: blood flow in capillaries of alveoli
b) Ventilation and perfusion must be matched (coupled) for
efficient gas exchange: one compensates for the other
i) If Ventilation insufficient: pp O2 low in dysfunctional
alveoli
• Regulates by: constricting arterioles at dysfunctional
alveoli & dilating arterioles to functional alveoli
ii) If Perfusion is insufficient: p. pressure CO2 is higher
in alveoli
• Regulate by: dilating bronchioles leading to the
dysfunctional alveoli to increase air movement &
constricts bronchioles going to functional alveoli
iii) Overall Result: Arterioles & Bronchioles regulated at
same time reaching an acceptable equilibrium = Vent-Perf
Coupling
3. Thickness and Surface Area of Respiratory
Membrane effects gas exchange
• Respiratory membranes
• 0.5 to 1 m thick
• Many capillaries  Large
total surface area
O2
CO2
Alveolus
Capillary
D. Internal Respiration
• Partial pressure
gradients are opposite
to those at the lungs
1. Arterial Blood At
Body Cells
O2 in Cells = 40
O2 in Arterioles = 100
 O2 diffuses from
blood to Body Cells
Veins
leaving Body
Cells &
Pulmonary
Arteries
40
Pulmonary
Veins &
Aorta
45
100 40
40
2. Venous Blood
Leaving Body Cells
CO2 in Cells = 45
CO2 in Arterioles = 40
 CO2 diffuses from
cells to blood
45
Body
Cells
Overview of External &
Internal Respiration
Inspired air:
PO2 160 mm Hg
PCO 0.3 mm Hg
Alveoli of lungs:
PO2 104 mm Hg
PCO 40 mm Hg
2
2
External
respiration
Pulmonary
arteries
Pulmonary
veins (PO2
100 mm Hg)
Blood leaving
tissues and
entering lungs:
PO2 40 mm Hg
PCO2 45 mm Hg
Blood leaving
lungs and
entering tissue
capillaries:
PO2 100 mm Hg
PCO2 40 mm Hg
Heart
Systemic
veins
Systemic
arteries
Internal
respiration
O2
CO2
V. Transport of Respiratory Gases by Blood
•
Both gases need specialized transport systems to move
the majority of the gases from body ↔ lungs
A. Introduction:
1. Active vs. Inactive Tissues
a) Active Tissues:
• Are using energy via Aerobic Respiration so have
• High CO2, Higher H+, Warmer
• Lower O2
b) Inactive Tissues:
• High O2
• Lower CO2, H+, Cooler
• CO2 + H20
H2C03
H+ + HCO3-
A. Introduction
…
2. Hemoglobin– four 02 per Hb
• Affinity for O2 changes with:
• How many O2 attached
• Local Conditions:
• pp O2: the higher, the easier O2 attaches to Hb
• Pocal conditions for active vs. Inactive tissues
(Pp CO2 , lower pH(more H+), Temperature)
• Reversibly binds O2– Loading & unloading
V. Transport of Respiratory Gases by Blood …
B. O2 Transport
1. Where O2 is held
• 1.5% dissolved in plasma
• 98.5% loosely bound to each Fe of hemoglobin (Hb)
•
1 billion per RBC
oxyhemoglobin
Fused basement membranes
Reduced
hemoglobin
CO
2
Alveolus
Red blood cell
O2 + HHb
Blood plasma
O2
O2
HbO2 + H+
O2 (dissolved in plasma)
(b) Oxygen pickup and carbon dioxide release in the lungs
B. O2 Transport …
2. Association of Oxygen and Hemoglobin
a. Movement of O2 ↔ Hb:
i) At Lungs: O2 diffuses from alveoli air ↔ dissolved
O2 in blood plasma  raises pp O2 so ↔ Hb
So pp O2 in blood keeps increasing as it diffuses
from alveoli to blood plasma
Alveolus
Hb in RBC
Blood Plasma
O2
O2
O2 (dissolved in plasma, is HIGH)
ii) At Body Cells: dissolved O2 in blood plasma →
interstial fluid, which lowers pp O2 of plasma …
NEXT SLIDE
a. Movement of O2 ↔ Hb …
ii) At Body Cells: dissolved O2 in blood plasma →
interstial fluid, which lowers pp O2 of plasma
• then O2 comes off Hb → interstial fluid
Body Cells
O2
O2 on Hb
O2 in Blood Plasma
b. Hb Affinity for O2 -- Loading & Unloading
• Loading: As O2 binds at lungs, Hb affinity for O2
increases
• Unloading: As O2 is released at body cells, Hb
affinity for O2 decreases
• Due to Hb shape changes
2. Association of Oxygen and Hemoglobin …
c. Influence of pp O2 on Hb saturation
Oxygen-Hemoglobin Dissociation Curve
i) AT LUNGS: Hb = 98:% saturated at Po2 = 100mm
ii) At higher pp Po2, a decrease in pp releases smaller
amounts of Po2 because are at curved area
iii) At lower pp Po2, each
decrease releases
increasingly more Po2
Additional
-Example: from 100 mm to
O2 unloaded
to exercising
80 mm Hb still have 98%
tissues
saturation.
But from 80 mm to 60mm
have 90% saturation
From 60 to 40 mm have
75% saturated
From 40 to 20 mm have
O2–Hb Saturation Curve
25 % saturation  a large amount of O2 released
2. Association of Oxygen and Hemoglobin …
c. Influence of pp O2 on Hb saturation …
Oxygen-Hemoglobin Dissociation Curve …
iv) Importance: Have
reserve of O2 in blood
• For:
Emergency/Exercise
• If PO2 of inspired air is
below normal, unloading
can still be adequate
• Application: high Altitudes
Additional
O2 unloaded
to exercising
tissues
O2–Hb Saturation Curve
d. Other Factors Influencing Hb Saturation
i) Increases in H+(decrease in pH) and Pco2: Weakens
the Hb-O2 bond (↓ affinity) and unloading increases
Bohr Effect –  CO2/H+
= Bohr Effect encourages O2 unloading
• Due to Modifying structure of Hb,
Decreased carbon dioxide
• Saturation curve: shifted to the right
(PCO 20 mm Hg) or H (pH 7.6)
• causing more O2 to
unload
• Example: Normal curve
from 60 to 40 mm,
Normal arterial
carbon dioxide
unload 15% O2
(PCO 40 mm Hg)
For ↑ CO2: 60 to 40
or H (pH 7.4)
releases 21% O2
Increased carbon dioxide
(P CO 80 mm Hg)
(unloaded)
or H (pH 7.2)
+
2
2
+
2
+
PO (mm Hg)
2
d. Other Factors Influencing Hb Saturation …
ii) Increases in temperature, H+, Pco2, and BPG
• Modify structure of Hb, affinity for O2   unloading)
• Saturation curve shifted to the right with higher
temperatures
10°C
20°C
38°C
43°C
Normal body
temperature
C. CO2 Transport
3 ways
1. 7 - 10% dissolved in plasma
2. 20% bound to globin of hemoglobin =
Carbaminohemoglobin
• Binds to amino acids of Globin,  no competition
• Catalyst? NO
3. 70% transported as bicarbonate ions (HCO3–) in plasma
Due to below reversible reaction
CO2
Carbon
dioxide
+
H2O
Water

H2CO3
Carbonic
acid

H+
Hydrogen
ion
+
HCO3–
Bicarbonate ion
3. As Bicarbonate …
• At Body Cells: CO2 diffuses into plasma, then into RBC
• In RBC: the enzyme Carbonic Anhydrase catalyzes its
reaction to form Carbonic Acid.
• This reaction is reversible.
• The Carbonic Acid, a weak acid, then becomes:
bicarbonate and diffuses out of RBC along its
gradient
• Chloride Shift: Cl- moves into the RBC to: replace
bicarbonate as the – ion and keep everything neutral
Tissue cell
Interstitial
fluid CO2
CO2
Plasma
CO2 (dissolved in plasma)
CO2 + H2O
Slow
H2CO3
HCO3– + H+
CO2
CO2
CO2
CO2 + H2O
Fast
H CO
2
3
Carbonic
anhydrase
HCO3– + H+
Red blood cell
HCO3–
Cl–
Cl–
Binds to
plasma
proteins
Chloride
shift
(in) via
transport
protein
3. As Bicarbonate …
• IN LUNGS: reaction reverses to unload CO2
• Dissolved CO2 in plasma: diffuses from plasma to alveoli
• Bicarbonate diffuses from plasma:  RBC, Cl- leaves RBC
• The reaction reverses to produce CO2 which diffuses out
of RBC  plasma, then alveoli
• The H+ created: by CO2 reaction with Water causes more
O2 to be unloaded (Bohr Shift)
Alveolus
Fused basement membranes
CO2
CO2 (dissolved in plasma)
CO2
CO2 + H2O
Slow
H2CO3
Blood plasma
HCO3– + H+
HCO3–
CO2
CO2 + H2O
Fast
H2CO3
Carbonic
anhydrase
HCO3–
+
H+
RBC
Cl–
Cl–
Chloride
shift
(out) via
transport
protein
4. Haldane Effect: O2 effects CO2 transport
= The lower the Po2 (and thus HbO2): the more CO2 can be
carried in blood (and vice versa)
• Because: Deoxyhemoglobin reacts more readily with CO2
In the lungs: O2 loaded/CO2 unloaded
Alveolus
Fused basement membranes
CO2
CO2 (dissolved in plasma)
CO2
CO2 + H2O
Slow
H2CO3
HCO3– + H+
HCO3–
Fast
CO2
H2CO3
CO2 + H2O
Carbonic
anhydrase
CO2
CO2 + Hb
Red blood cell
HCO3–
+
H+
HbCO2 (Carbaminohemoglobin)
O2 + HHb
HbO2 + H+
Cl–
Cl–
Chloride
shift
(out) via
transport
protein
O2
O2
O2 (dissolved in plasma)
Blood plasma
(b) Oxygen pickup and carbon dioxide release in the lungs
Figure 22.22b
• OVERALL AFFECT: Bohr Shift and Haldane Effect
• At tissues, as more CO2 enters blood (H+↑)
• More O2 dissociates from Hb (Bohr effect, i.e. CO2 effects O2)
• As HbO2 releases O2, it more readily forms bonds with CO2 to
form carbaminohemoglobin
C. CO2 Transport
5. Influence of CO2 on Blood pH
1. Carbonic Acid-Bicarbonate Buffer System
H2CO3
Carbonic
acid

H+
Hydrogen
ion
+
HCO3–
Bicarbonate ion
a. Alkaline Reserve: the HCO3- in plasma as Buffer Sys
b. Changes in pH (usually via metabolic factors)
• If H+  in blood: excess H+ removed by
combining with HCO3–
• If H+ : H2CO3 dissociates, releasing H+
c. Respiratory Sys Regulation: by Changing
Ventilation (rate or depth)
• slow/shallow: less CO2 moved out blood   pH
• rapid/deep: more CO2 moved out blood   pH)
VI. Control of Respiration
Pons
Medulla
Pontine respiratory centers
interact with the medullary
respiratory centers to smooth
the respiratory pattern.
Ventral respiratory group (VRG)
contains rhythm generators
whose output drives respiration.
Pons
Medulla
Dorsal respiratory group (DRG)
integrates peripheral sensory
input and modifies the rhythms
To inspiratory
generated by the VRG.
muscles
Diaphragm
External
intercostal
muscles
VI. Control of Respiration …
A. Neural
Mechanisms
Pons
• Involves neurons in
Pons
Medulla
reticular formation Pontine respiratory centers Medulla
Pontine
respiratory
centers
with
the medullary
of medulla and ponsinteract
interact with
the medullary
respiratory
centers
to smooth
1. Medulla
Oblongata
Respiratory
Centers
a. Ventral
Respiratory
Group
respiratory
centers
to smooth
the
respiratory
pattern.
the respiratory
pattern.
Ventral
respiratory
group (VRG)
Ventral
respiratory
group (VRG)
contains rhythm generators
contains
rhythm
generators
whose
output
drives
respiration.
whose output drives respiration.
Pons
Pons
Medulla
Medulla
Dorsal respiratory group (DRG)
Dorsal respiratory
group (DRG)
integrates
peripheral sensory
integrates
peripheral
sensory
input
and modifies
the rhythms
input andby
modifies
the rhythms To inspiratory
generated
the VRG.
To inspiratory
muscles
generated by the VRG.
muscles
Diaphragm
Diaphragm
External
External
intercostal
intercostal
muscles
muscles
VI. Control of Respiration …
A.
Neural Mechanisms …
1. Medulla Oblongata …
a. Ventral Respiratory
Group …
• Inspiration: Certain
neuron send
impulses to
Diaphragm and
External
Intercostals
Pons
Pons
Medulla
Medulla
Pontine respiratory centers
Pontine
respiratory
centers
interact
with
the medullary
interact with
the medullary
respiratory
centers
to smooth
respiratory
centers
to smooth
the
respiratory
pattern.
the respiratory
pattern.
Ventral
respiratory
group (VRG)
Ventral
respiratory
group (VRG)
contains rhythm generators
contains
rhythm
generators
whose
output
drives
respiration.
whose output drives respiration.
Pons
Pons
Medulla
Medulla
Dorsal respiratory group (DRG)
Dorsal respiratory
group (DRG)
integrates
peripheral sensory
integrates
peripheral
sensory
input
and modifies
the rhythms
input andby
modifies
the rhythms To inspiratory
generated
the VRG.
To inspiratory
muscles
generated by the VRG.
muscles
• Expiration: Other
neurons send
inhibitory impulses
to cause expiration
• Rhythm generating:
Eupnea- normal
Diaphragm
Diaphragm
External
External
intercostal
intercostal
muscles
muscles
VI. Control of Respiration …
A.
Neural Mechanisms
1. Medulla Oblongata …
b. Dorsal Respiratory Group
Pons
• Integrates information from peripheral
Pons
Medulla
Medulla
stretch receptors
& chemoreceptors
Pontine
respiratory centers 
Pontine
respiratory
centers
with
the medullary
sends to VRG interact
interact with
the medullary
respiratory
centers
to smooth
respiratory
centers
to smooth
the
respiratory
pattern.
the respiratory
pattern.
2. Pons– Pontine Ventral
respiratory
group (VRG)
Ventral
respiratory
group (VRG)
contains rhythm generators
Respiratory
contains
rhythm
generators
whose
output
drives
respiration.
whose output drives respiration.
Pons
Centers
Pons
Medulla
Medulla
Fine tunes
Dorsal respiratory group (DRG)
Dorsal respiratory
group (DRG)
integrates
peripheral sensory
rhythum for
integrates
peripheral
sensory
input
and modifies
the rhythms
input andby
modifies
the rhythms To inspiratory
the VRG.
vocalizations, generated
To inspiratory
muscles
generated by the VRG.
muscles
sleep, exercise
by influencing
Diaphragm
VRG
Diaphragm
External
External
intercostal
intercostal
muscles
muscles
B. Factors Influencing Breathing
Depth and Rate
Arterial PCO2
- modification for changing body
demands’
H in
CO
2
Both types of
chemoreceptors increase
ventilation
1. Chemical Factors
a. CO2 diffuses across
blood-brain barrier,
forms ↑H2CO3 =
↑H+ in brain ECF
brain extracellular
fluid (ECF)
Central chemoreceptors
in medulla respond to H+
in brain ECF (mediate 70%
of the CO2 response)
• Brain pH ,
chemoreceptors in
medulla 
ventillation
b. Arterial pH 
stimulates
peripheral
chemoreceptors
Peripheral chemoreceptors
in carotid and aortic bodies
(mediate 30% of the CO2
response)
Afferent impulses
Medullary
respiratory centers
Efferent impulses
Respiratory muscle
Ventilation
(more CO2 exhaled)
Initial stimulus
Physiological response
Result
Arterial PCO2 and pH
return to normal
Brain
c. PO2 is NOT a common stimulus
• Only if arterial PO2 < 60mm,
will peripheral Chemoreceptors
↑ ventilation
Carotid body
Cranial nerve X (vagus nerve)
Aortic bodies in aortic arch
Aorta
Heart
Figure 22.26
2. Other Influences
Emotions & Higher
Brain Regions
Other receptors (e.g.,
pain) and emotional
stimuli via hypothalamus
+
–
Higher brain centers
(cerebral cortex—voluntary
control over breathing)
+
–
Peripheral
chemoreceptors
O2 , CO2 , H+
Central
Chemoreceptors
CO2 , H+
Respiratory centers
(medulla and pons)
+
+
–
–
Stretch receptors in
lungs (Hering-Breuer
(inflation) reflex)
+
Receptors in
muscles and joints
Irritant
receptors
Figure 22.24
3. Respiratory Adjustments: Exercise
• Depends on: ntensity and duration of exercise
• Hyperpnea
• Increase in ventilation 10 to 20 fold
• Pco2, Po2, and pH remain surprisingly constant during exercise
Acclimatization to High Altitude
• Substantial  in Po2 stimulates peripheral chemoreceptors
• Result: minute ventilation increases in a few days to 2–3 L/min
• Decline in blood O2 stimulates kidneys to  production of EPO
(erythropoietin)  ↑ RBCs over long-term
Homeostatic Imbalances
• Chronic obstructive
pulmonary disease
• STUDENTS DO
END OF PPT
• REVIEW QUESTIONS
• EXTRA SLIDES
Review
A. ID
B. ID
C. What type
of E.T. is
found here?
Review Questions
The _____________
pseudostratified ______
ciliated columnar
________ epithelium of
mucus and gives
the nasal cavity helps move _________
stratified _________
squamous epithelium in the
way to ________
friction
oropharynx to protect against ___________
from
food.
How many lobar bronchi are there?
5 = 3 right + 2 left lobes
Review Questions
The ___________
respiratory membrane
________ is where respiratory
alveoli to the blood
gases diffuse from air in the ________
plasma.
Intrapleural (Pip) pressure is always _____
less than
intrapulmonary pul) pressure, otherwise the lungs
_____________(P
would do what?
Collapse (atalectasis)
Review Questions
Which of the following physical factors would
negatively effect pulmonary ventilation?
A.
B.
C.
D.
E.
Increased resistance to flow
Increased lung compliance
Decreased alveolar surface tension
A and C only
All of the above
_______
Dead _______
space is the portion of gas in the lungs that
does not participate in active gas exchange.
Review Questions
In a mix of gases, the
partial pressures
________
_________ of
each gas and its
solubility
___________
in the
liquid determine the
direction and quantity of
diffusion.
How does rapid, shallow
breathing effect alveolar
respiration rate, i.e.
actual gas exchange?
Reduces it.
Review Questions
As CO2 enters the blood, what happens to blood pH?
Decreases (H+ increases)
What happens to the ability of Hb to hold onto O2 as
CO2 levels increase?
Decreases (Bohr effect)
O2 on
The Haldane effect describes the influence of ____
CO2
the capacity of blood to carry _____.
Review Questions
What brain regions have primary
control over respiration?
Pons and Medulla
The primary stimulus for
regulating respiration rates is
CO2 and
the concentration of _____
its eventual production of ___
H+
ions.
Long term acclimation is
regulated by what organs?
kidneys
Middle lobe
of right lung
Superior lobe
of left lung
Left main
(primary)
bronchus
Lobar
(secondary)
bronchus
Segmental
(tertiary)
bronchus
Inferior lobe
of right lung
Inferior lobe
of left lung
Superior lobe
of right lung
External Respiration
In Lungs
• O2 Partial pressure gradient:
• Alveolar Po2 = 104 mm Hg
• Venous blood Po2 = 40 mm Hg
• O2 reaches equilibrium in ~0.25 s
•
1/3 the time RBC in capillary
• CO2 Partial pressure gradient:
• Alveolar Pco2 = 40 mm Hg
• Venous blood Pco2 = 45 mm Hg
Inspired air:
PO2 160 mm Hg
PCO 0.3 mm Hg
Alveoli of lungs:
PO2 104 mm Hg
PCO 40 mm Hg
2
2
External
respiration
Pulmonary
arteries
Pulmonary
veins (PO2
100 mm Hg)
Blood leaving
tissues and
entering lungs:
PO2 40 mm Hg
PCO2 45 mm Hg
Blood leaving
lungs and
entering tissue
capillaries:
PO2 100 mm Hg
PCO2 40 mm Hg
Heart
• CO2 diffuses in equal amounts w/ O2
Systemic
veins
Systemic
arteries
Internal
respiration
O2
CO2
Figure 22.17
In the body tissues: O2 unloaded/CO2 loaded
Tissue cell
Interstitial fluid
CO2
CO2
CO2 (dissolved in plasma)
CO2 + H2O
Slow
H2CO3
HCO3– + H+
CO2
Fast
CO2
CO2 + H2O
H2CO3
Carbonic
anhydrase
CO2
CO2 + Hb
HbCO2 (Carbaminohemoglobin)
Red blood cell
HbO2
O2 + Hb
CO2
CO2
HCO3– + H+
HCO3–
Cl–
Cl–
HHb
Binds to
plasma
proteins
Chloride
shift
(in) via
transport
protein
O2
O2
O2 (dissolved in plasma)
Blood plasma
(a) Oxygen release and carbon dioxide pickup at the tissues
Figure 22.22a