Transcript 1. Pulmonary ventilation

Respiratory System




Living cells need energy for maintenance,
growth, defense, and replication
Aerobic respiration
Body requires O2 and produces CO2
Our bodies can achieve this by our
respiratory exchange surfaces inside the
lungs
Functions of the
Respiratory System




1. moves air to and from the gas- exchange
surfaces
2. provides defense against pathogenic
invasion
3. permits vocal communication
4. helps control body fluid pH
Respiratory Tract





Conducting portion and Respiratory portion
Conducting airways carry air to and from the
exchange surfaces on the lungs
these airways filter, warm and humidify the air
This protects the alveoli from debris, pathogens
and environmental extremes
Respiratory Portion includes the smallest and most
delicate bronchioles and alveoli that are the site
for gas exchange
The Nose


Air enters the respiratory system via the
external nares (nostrils)
Coarse hairs guard the nasal cavity from
large airborne particles such as sand, dust
and insects
The Pharynx


Chamber shared by the digestive and
respiratory systems
Extends between the internal nares and
the entrance to the larynx and esophagus



Hyoid bone is a bone in the
neck, that sits on top of the
larynx
It is the only bone in the
human skeleton not articulated
to any other bone.
It is supported by the muscles
of the neck and in turn
supports the root of the
tongue.
The Larynx




Incoming air leaves the pharynx, passes through
the glottis, which is surrounded and protected by
the larynx
Prevents food from going down the trachea
Filters air, voice box
Vocal cords vibrate when air passes through the
glottis generating sound waves

At puberty, the larynx of a male enlarges more than
that of a female. Their vocal cords are thick and longer
with lower tones compared to a female.
The Trachea





“windpipe”
Tough, flexible tube
~ 11 cm long and 2.5 cm in diameter
The cartilage bands of the trachea support it
and keep it from collapsing (~20 of them)
C-shape of the cartilages face towards the
esophagus and do not continue around the trachea
Tracheal Blockage




Foreign objects can become lodged in larynx or
trachea
Coughing can expel the object if the airway isn’t
completely blocked.
If a person cannot breathe or speak, immediate
action must be taken
Heimlich Maneuver or abdominal thrust

This elevates the diaphragm forcefully and can
generate enough pressure to remove the object.
Thyroid Gland





Regulates metabolism by secreting Thyroxine
Maintains hormone levels
common thyroid problems involve abnormal
production of thyroid hormones.
Hyperthyroidism- due to an overproduction of
thyroid hormones
Hypothyroidism- due to an underproduction of
thyroid hormones.
Bronchi



Left Bronchus- takes air to the left lung
Right Bronchus- takes air to the right lung
C-Shaped rings that resemble the tracheas
Bronchial Tree




Think of a tree having a trunk (trachea), two
large branches (L. Bronchi & R. Bronchi)
Each of the large branches give rise to
secondary bronchi that enter the lobes of that
lung.
The bronchi divide into 9-10 smaller tertiary and
the bronchi become smaller and smaller.
When the passageways diameter is <1 mm, the
narrow passage is a bronchiole
Bronchioles





Control the amount of resistance to air flow
Control the distribution of air in the lungs
Sympathetic activation leads to a relaxation
of smooth muscles in the walls causing
dilation of the respiratory passageways
Constriction can block the passageways
Ex. Asthma or allergic reactionsinflammation of the bronchioles
Alveolar Ducts and Alveoli




Bronchioles open into chambers called
alveolar ducts
The passageways end at the alveolar sacs
Alveolar sacs- supply air to alveoli
Alveoli- pockets at the end of the
respiratory tree

Gas exchange with the blood occurs here
across the respiratory membrane
Gas exchange by diffusion in the
lungs
The alveoli have a capillary
network
CO2 leaves the veins and Oxygen
enters the alveoli
Pneumonia





Infection of the lobules of the lung
causing inflammation
Respiratory function deteriorates
Swelling and constricting of the respiratory
bronchioles
More likely when respiratory defenses are
compromised by other factors
For ex. Smoking, AIDS
The Lungs








Area of gas exchange
Left and Right Lobes
Paired organs of respiration
Left- area of gas exchange on L. side
Anterior Lobe of Right Lung
Median Lobe of Right Lung
Posterior Lobe of Right Lung
Postcaval Lobe of Right Lung
Lungs



Most of the actual volume of each lung
consists of air-filled passageways and
alveoli
The lung is light and spongy
Elastic fibers give the lungs the ability to
tolerate large changes in volume
Lung Capacity




The total volume of the lungs can be divided
into volumes and capacities
Expiration reserve vol.- amt. of air that could be
voluntarily expelled
Inspiratory reserve volume- amt. of air that can
be taken in
Vital capacity- sum of the inspiratory reserve vol.
+ expiratory reserve vol. + the tidal vol. = vital
capacity
Lung Capacity Cont.


Residual Volume- air that remains after
exhausting the expiratory reserve vol.
Minimal Volume- when the lungs collapse
and the amt. of air in the respiratory
system is reduced to the minimal vol.
Pleural Cavities




The thoracic cavity has a broad cone shape
The walls are the rib cage and its floor is
the muscular diaphragm
Diaphragm separates the thoracic cavity
from the abdominal cavity
Each lung occupies a single pleural cavity,
lined by a pleura membrane
Pleural Cavity
Respiration Process

1. Pulmonary ventilation or breathing




Movement of air in and out of lungs
2. Gas diffusions across respiratory
membrane
3. Storage and transport of oxygen and
carbon dioxide
4. Exchange of oxygen and carbon dioxide
between the blood and intestinal fluids
Tuberculosis







TB results from a bacterial infection of the lungs
Bacteria colonize in the respiratory passageways
or alveoli
Symptoms vary- usually coughing and chest
pain, fever, night sweats, fatigue, wt. loss
Major health problem throughout the world
Transmitted through casual contact
Basically anyone alive and breathing is at risk
~ 2 billion are infected at this time and 8 mill.
Cases are diagnosed each year
Bacteria have colonized in the respiratory passageways or alveoli
Can target almost any part of your body
Pulmonary Ventilation



Physical movement of air into and out of
the respiratory tract
A single breath or respiratory cycle
consists of an inhalation (inspiration) and
an exhalation (expiration)
In other words, breathing in and out one
time is a respiratory cycle
Emphysema




Chronic, progressive condition
Shortness of breath and inability to tolerate
physical exertion
Destruction of the alveolar surfaces and
inadequate surface area for oxygen and
carbon dioxide exchange
Linked to inhalation of air containing fine
matter or toxic vapors Ex) cigarette smoke
Gas Pickup and Delivery




Oxygen is retained by hemoglobin
If a tissue has a low oxygen content, oxygen will
be released by hemoglobin
Carbon Dioxide all transports are reverseable
after entering the bloodstream can CO2 may be:



1. dissolved in the plasma
2. bound to the hemoglobin in RBC
3. converted to a molecule of carbonic acid



Carbonic acid breaks down into a
hydrogen ion and a bicarbonate ion
Most hydrogen ions get bound up by
hemoglobin molecules
Bicarbonate ions diffuse in to the
surrounding plasma

Here they associate with sodium ions to form
sodium bicarbonate (NaHCO3)
Carbon Monoxide Poisoning



Each year entire families can be killed by
leaky furnaces or space heaters
Found in the exhaust of automobiles, oil
lamps, space heaters
Carbon monoxide competes with oxygen
for the binding sites on heme units and
usually wins because it has a much
stronger affinity for hemoglobin
Anemia





a deficiency of red blood cells or the
hemoglobin molecules within them
Oxygen has trouble getting where to it needs
to go because hemoglobin is not accessible
Therefore, the blood struggles to bring oxygen
molecules to tissues for energy in the body
This can be very serious because the human
body depends on oxygen to survive.
Ex.) holding your breath under water
Weakness, fatigue
SIDS






Sudden Infant Death Syndrome
“crib death”
Kills ~ 10,000 infants each year in the United
States alone
Usually in infants 2-4 months old and usually
between midnight and 9 am in the late fall and
winter months
Eyewitness accounts- infant suddenly stops
breathing, turns blue and relaxes
Causes-many ideas- genetic, respiratory
infections, sleeping position, environment
Lung Cancer





Originates in the bronchial passageways or
alveoli
85-90% of all lung cancers are the direct result
of cigarette smoking
Symptoms usually don’t appear until the point
when the tumor masses are restricting airflow.
Common symptoms- cough, wheeze, chest pain,
shortness of breath, wt. loss
Treatments vary- surgery, radiation or
chemotherapy may be involved
Lung Cancer





Incidence of lung cancer for
Nonsmokers- is 3.4 per 100,000
Smokers (half a pack and a pack a day)
59.3 per 100,000
Smokers (one to two packs a day) 217.3
per 100,000
This isn’t surprising with all the toxic
chemicals contained in the smoke