Download Respiratory System

Respiratory System
Inhalation and exhalation
Ventilation
The Respiratory Centers of the
Brain
• PONS.
• The apneustic center causes strong and sustained inspiratory
movements.
• The pneumotaxic center controls medullary activity
– Turns off inspiration
– Medulla
• Dorsal respiratory group- Inspiratory
– Acts as pacemaker, expiration occurs when signal from these
nerves stops.
• Ventral respiratory group- both inspiratory and expiratory
– Inactive during normal breathing, speed up inspiratory activity when
demands are high
Nervous
control of
breathing
• Chemoreceptors
detect changes in
pH of blood
– Send signal to
breathing control
centers in pons and
medulla oblongata.
• Nerve signals tell
lungs to inhale
Oxygen/CO2 transport in blood
• Oxygen
– Dissolved in blood
1.5%
– Bound to hemoglobin
98.5%
• CO2
– Dissolved in blood
10%
– Bound to hemoglobin
30%
– As bicarbonate
60%
carbon dioxide transport in blood
• From cells
– RBC’s and blood pick
up CO2 and transport it
as carbonic acid
(HCO3)
– In lungs (at alveoli)
CO2 is released and
travels by diffusion to
alveoli.
Compare PO2
and PCO2 in
blood and air
• Inhaled air
• Blood leaving alveolar
capillaries
• Blood leaving tissue
capillaries
• Exhaled air
Structures of the respiratory system
Pathway of air traveling through the respiratory system
mouth/nasal cavity– pharynx– trachea– bronchus– bronchiole– alveoli
Tissues of voice production
• epiglottis
• Vocal folds (chords)
• Larynx
Larynx
• specialized structure
atop the windpipe,
responsible for
– sound production,
– air passage during
breathing
– protecting the airway
during swallowing
Vocal Folds (aka Vocal Cords)
• “Fold-like" soft tissue that is the main
vibratory component of the voice box;
comprised of a
– cover (epithelium and superficial lamina propria),
– vocal ligament (intermediate and deep laminae propria),
– body (thyroarytenoid muscle)
Vocal folds
Glottis
• Opening between the two vocal folds;
– the glottis opens during breathing and
– closes during swallowing and sound
production
How we get voice
• voice has three components
– Voiced sound: The basic sound produced by
vocal fold vibration is called "voiced sound."
• This is described as a "buzzy" sound.
– Resonance: Voice sound is amplified and
modified by the vocal tract resonators (the throat,
mouth cavity, and nasal passages).
• This produces a person's recognizable voice.
– Articulation: The vocal tract articulators (the
tongue, soft palate, and lips) modify the voiced
sound.
• This produces recognizable words.
Comparing external and internal
respiration
• External respiration involves the
exchange of gases between the alveolar
air and the pulmonary capillaries.
• Internal respiration occurs when gas
diffuses between peripheral capillaries and
the fluid surrounding cells.
Decompression Sickness
(the bends)
• It is the result of diffusion
between liquids and gases:
– Differences in pressure moves
air from one place to another
and force gas molecules into
solution.
• The bends occur when
pressure decreases rapidly,
and gas molecules leave
solution to form bubbles in
body fluids.
– Nitrogen is usually the gas
responsible for the observed
symptoms.
How “the bends” got its name
Pneumothorax
• occurs when air leaks
from inside of the lung to
the space between the
lung and the chest wall.
• The lung then collapses.
• The dark side of the chest
(right side of the picture)
is filled with air that is
outside of the lung tissue.
– Can result from
• ascent in diving without
exhaling
• A bone or other object
puncturing the lung
Tuberculosis
• characterized by
white lesions or
tubercles which
replace alveoli with
scar tissue.
– Creates poor gas
exchange in the lungs.
– Symptoms: coughing,
sputum production,
lethargy and
breathlessness.
• Caused by a bacterial
infection
– Spread through the air.
• Almost impossible to
transmit b/w people
except with repeated
exposure.
• Most infected people
never develop the
disease.
Tuberculosis xray
Emphysema
• Cause
– Lung has a balance b/w
two chemicals that help
maintain elastic fibers
around alveoli.
– When balance is altered,
elastic fibers are destroyed
and alveoli are enlarged.
– Enlarged alveoli are less
efficient at gas exchange.
– Patient is left short of
breath
– Smoking is primary culprit.
Asthma
• a disease of the bronchial
tubes,
– During normal breathing, the
bands of muscle that surround
the airways are relaxed,
– with asthma, allergy-causing
substances or environmental
triggers make the bands of
muscle surrounding the
airways tighten, and air cannot
move freely.
• Causes
– People have very sensitive
airways that react to many
environmental "triggers."
• Contact with these triggers
cause asthma symptoms
– Triggers include
• Infections (colds, viruses,
flu, sinus infection)
• Allergens such as pollens,
mold spores, pet dander
and dust mites
• Irritants such as strong
odors from perfumes or
cleaning solutions, air
pollution,
• Tobacco smoke
• Exercise or exertion
• Weather -- changes in
temperature and/or
humidity, cold air
Oxygen unloads from hemoglobin more
as pH decreases
Carbon Monoxide Poisoning
• Most common
cause of toxin
induced death.
• Difficult to
detect, it is the
great imitator of
other
conditions.
3 reasons why CO poisoning is
toxic
• direct binding of CO to hemoglobin;
– One molecule of CO blocks a whole hemoglobin from
carrying oxygen.
• shifting the oxygen-hemoglobin dissociation
curve;
– Hemoglobin gives up less oxygen to tissue when it is
bound to CO
• CO binding to myoglobin;
– Slow twitch muscle fibers can’t use myoglobin and
they starve for oxygen.
– Heart muscle tissue suffers the same fate.
Symptoms
• Headache, dizziness, agitation, stupor,
seizures, and coma are the most common
neurological symptoms.
– In one study with acute CO poisoning, 90%
had headache.
– physicians should attempt to identify the use
of gas stoves and other cohabitants with the
same symptoms to determine a correct
diagnosis.