Transcript Respiratory System

Chapter 16
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THE RESPIRATORY
SYSTEM
Functions:
-Obtain oxygen
-Remove carbon dioxide
-Trap particles from the air
-Warm the incoming air
- Produce vocal sounds
-Smell
-Regulate blood pH
Respiration - gas exchange between
between atmosphere and cells
Events of Respiration:
-Air in and out of lungs = ventilation
-Gas exchange between blood and air
-Gas transport in blood
-Gas exchange between blood and cells =
cellular respiration
Upper Respiratory System pharynx and
superior
Lower Respiratory System - larynx and
inferior
Upper Respiratory Tract
Structures
Nasal Conchae - support the mucous
membrane & increase it’s surface area
Mucous membrane - has
pseudostratified ciliated epithelium
and is rich in goblet cells that secrete
mucus
-has extensive blood vessels within so
warms air
-Sticky mucous traps dust and other
small particles
SINUSES - air filled spaces in the
maxillary, frontal, ethmoid and
sphenoid bones of the skull; decrease
the weight of the skull and affect
voice quality
MUCUS MOVEMENT AND CILIA
Cilia move mucus and particles toward the pharynx where the
mucus is swallowed and digestive juices destroy invaders
LARYNX
Enlargement in the airway at the
top of the trachea below the
pharynx
Conducts air in and out
Prevents foreign objects from
entering the trachea
Houses the vocal cords
Made of: muscles and cartilages
bound by elastic tissue
Upper folds: false vocal cords
Lower folds: true vocal cords
VOCAL CORDS
Word sounds result from change in
shape of the pharynx cavity
Increases of tension increases pitch
Decreases of tension lowers pitch
Stronger blasts of air = louder
sounds
Lighter blasts of air = quieter sounds
The glottis closes when food or
drink is swallowed
The epiglottis is a flaplike structure
that allows air into the larynx and
presses downward when food or
water enters
LARYNGITIS - the
mucus membrane of the
larynx is inflamed and
swollen secondary to
infection or irritation
preventing vocal cord
vibration
THE BRONCHIAL TREE
TRACHEA - flexible,
cylindrical tube
anterior to the
esophagus and runs
into the thoracic cavity
-has a ciliated mucous
membrane with goblet
cells to move particles
to the pharynx where
they are swallowed
-Has “c shaped”
cartilages to keep the
airway open
THE TREE - branched
airways from trachea to
small air sacs in the
lungs
THE PASSAGEWAYS
OF THE
RESPIRATORY
SYSTEM
Bronchioles have smooth
muscle walls
Alveoli - have
a thin layer of
squamous
epithelial cells
for gas
exchange
Figure 16.09
GAS EXCHANGE FROM
ALVEOLI TO VESSELS
THE LUNGS - reside in the thoracic cavity and are separated by the mediastinum; the right lung
has 3 lobes and the left has 2 lobes
VISCERAL PLEURA - serous membrane that directly attaches to the lungs and folds back to form
the parietal pleura
PLEURAL CAVITY - not a real cavity - serous fluid resides in this cavity to allow for friction
reduction during breathing
BREATHING MECHANISMS
INSPIRATION = moving air from outside of the body inside the lungs
EXPIRATION = moving air from inside the lungs out
AIR MOVES INTO THE LUNGS BECAUSE PRESSURE OUTSIDE OF THE LUNGS IS GREATER THAN
PRESSURE INSIDE = INSPIRATION
WHEN AIR PRESSURE INSIDE THE LUNGS IS GREATER THAN ATMOSPHERIC PRESSURE (AIR OUTSIDE
OF THE LUNGS) WE CAN EXHALE = EXPIRATION
MAXIMAL
INSPIRATION
MAXIMAL EXPIRATION
SURFACTANT AND ALVEOLI
Alveolar cells have surfactant which reduces their tendency to
collapse when lung volumes are low
Surfactant allows for easier inspiration and inflation of the alveoli
If a child is born without surfactant (or is a premie) synthetic
surfactant may be injected into the lungs via an endotracheal tube
Without the surfactant a newborn is unable to inflate their lungs
RESPIRATORY AIR VOLUMES
RESPIRATORY AREAS
-are groups of neurons in the
brainstem that control inspiration
and expiration
-Scattered throughout the medulla
oblongata and pons
-medullary respiratory center - aka
dorsal respiratory group stimulates muscles of inspiration
-Ventral respiratory group controls intercostal and abdominal
muscles
- pontine respiratory group controls
the rhythmicity of breathing
EMPHYSEMA AND LUNG CANCER
- EMPHYSEMA - progressive, degenerative disease that destroys
alveolar walls leading to loss of tissue elasticity and difficulty
expelling air from the lungs
- LUNG CANCER - uncontrolled division of abnormal cells
-may start in another area such as the breast and metastasize to
the lungs
-PRIMARY PULMONARY CANCERS - start in the lungs
-BRONCHOGENIC CARCINOMA - originates from epithelium
in a bronchiole secondary to prolonged irritation from a substance
like tobacco smoke
-Cancer cells eventually form tumor masses that obstruct air
passages and decrease gas exchange
-These cancers spread easily to the circulation leading to lymph
node, liver, bones brain or kidney metastasis.
Figure 16.17
FACTORS THAT AFFECT
BREATHING
-Chemoreceptors in the medulla
oblongata detect changes in CSF,
CO2 and Hydrogen
-If high amounts are detected
then increase in breathing occurs
to decrease the chemical levels
- carotid and aortic bodies sense
blood O2 level change
-If blood O2 is very low then
respiration is triggered to
increase
-Inflation reflex - prevents
overinflation of the lungs with
forceful breathing
-Hyperventilation - lowers the
level of CO2 levels
THE RESPIRATORY
MEMBRANE
Alveoli are lined with simple
squamous epithelium and in
close association with
capillaries
The membrane is a layer of
fused basement membranes
and simple squamous
epithelium
Gas molecules diffuse from
high concentration to low aka
high pressure to low pressure
GAS EXCHANGE BETWEEN CAPILLARY AND ALVEOLI
Partial pressure - the amount of pressure that each gas exerts
Movement occurs across the respiratory membrane until
equilibrium is reached
Soluble gases like alcohol and acetone can diffuse into alveoli
OXYGEN TRANSPORAT ACROSS THE RESPIRATORY MEMBRANE
Oxygen binds primarily to the iron-containing protein hemoglobin
Oxyhemoglobin molecules are unstable and favor release of oxygen
when it is in demand (such as in exercise)
CARBON DIOXIDE TRANSPORT
CO2 readily diffuses into the blood as its concentration is high in the
tissues
Carbaminohemoglobin - CO2 bound to hemoglobin
BICARBONATE AND CARBONIC ANHYDRASE
Carbon dioxide is transported in the form of a bicarbonate ion
HCO3 to = H2CO3
Carbonic anhydrase speeds the reaction between CO2 and H2O
to break the H2CO3 molecule into a hydrogen and bicarbonate
Hydrogen ion concentration variances can raise or lower blood
pH
CYSTIC FIBROSIS AND CARBON MONOXIDE POISIONING
CYSTIC FIBROSIS - salty skin is a common symptom
-causes thick mucus which leads to infections
-Chloride channel is missing an amino acid so it is deformed and
chloride stays in the cell
-Water moves into the cell via osmosis and has to way to leave
thus organs become clogged
-There is no effective treatment to date
CARBON MONOXIDE POISONING - carbon monoxide binds
to hemoglobin preventing oxygen from binding leading to
gradual tissue death