Download Respiratory_System 2015

Respiratory
System
Chapter 16
Functions
1. Obtain O2 and remove CO2
2. Filter and trap incoming particles
3. Control temperature and water
content of incoming air.
4. Produce vocal sounds
5. Help to regulate blood pH
Structures
• Nose, nasal cavity and
sinuses
• Pharynx
• Larynx
• Trachea
• Bronchial tree
• Lungs
Nose, Nasal Cavity and Sinuses
• Hairs filter air
• Mucus
• Membranes moisten
air
• Capillaries warm air
• Nasal sinuses affect
vocal sound and
reduce weight of skull
Nasal conchae – bones that divide the
nasal cavity, support the mucus
membrane and increase surface area
(superior, middle, inferior)
* deviated septum – when the
septum bends to one side
Larynx
• Contains vocal cords
• Vibration of cords
makes sound.
• Glottis is slit-like
opening between
vocal cords.
• Epiglottis is flap to
cover windpipe when
swallowing food.
• Adam’s apple –
thyroid cartilage
Laryngitis: Inflammation/swelling of the vocal
cords; caused by infection or irritation of mucous
membranes
- false vocal
folds (do not produce
sound) – help close airway
during swallowing
- true vocal folds
(produce sound) – changing
shape of the pharynx, and
oral cavity changes sounds
into words
- contracting and
relaxing muscles changes
pitch (increased tension =
higher pitch)
Trachea
• Cartilage C-rings give
support.
• Ciliated mucous
(pseudostratified
epithelial) tissue
filters air
• Endotracheal Tube:
tube inserted into
trachea to restore air
passageway (video)
• Tracheotomy:
surgical opening of
trachea
Bronchial Tree
•
•
•
Branched airways
leading from trachea to
alveolar sacs.
Divisions of tree:
- Bronchi (1, 2, 3)
- Bronchioles
- Alveolar sacs
Disorders:
1. Asthma – muscular
constriction of airways
2. Bronchitis – inflammation
of mucosal lining
Lungs
• Soft, spongy organs
• 3 right lobes, 2 left
lobes
• Visceral pleura and
parietal pleura line
surface of lungs
creating potential
space = pleural cavity.
• Pleural cavity
contains serous fluid
to reduce friction
between layers.
Pneumothorax – air enters pleural cavity
collapsing lung
Alveoli
• Site of gas exchange
• Increases surface area
• Respiratory membrane
consists of 3 layers:
A – alveolar membrane
B – basement membrane
C – capillary membrane
• Surfactant – substance
released from epithelium
to reduce surface tension
(cohesive forces between
water molecules) inside
open air sacs.
Lung
disorders:
cancer and
emphysema
Mechanics of Breathing
• Air flows into and out
of the lungs due to a
pressure gradient,
between the
atmospheric pressure
and the pressure
inside the lungs.
• Air moves from high
to low pressure
Normal, quiet exhalation = Elastic recoil of
tissues (lungs and muscles) .
Forceful exhalation = internal intercostal
muscles and abdominal muscles.
Animation!
Normal inspiration:
due to pressure
difference when
thoracic cavity
increases from
diaphragm and
intercostal muscle
contractions.
Forceful inspiration: Muscles such as the external intercostals,
pectoralis and sternocleidomastoid can further increase the
internal lung space.
NON RESPIRATORY
MOVEMENTS
Coughing, sneezing,
laughing, crying
Hiccup - spasm of the
diaphragm
Yawn - possibly causes by
low oxygen levels
How much can we breathe in
or out in one breath?
Measuring Lung Volume…
Average pair of human lungs can hold 6 Liters of
air.
1. Why do Pulmonary
Function Tests need
to be performed?
* Measures lung
function and can
assess conditions like
asthma, pulmonary
fibrosis, cystic fibrosis,
& COPD.
2. How is lung volume
measured?
* Using a
SPIROMETER
Lung Capacities
• During normal breathing (at rest), approx. 500ml of air
is exchanged = TIDAL VOLUME (TV)
• Maximum forced inhalation amount = INSPIRATORY
RESERVE VOLUME (IRV)
• Maximum forced exhalation = EXPIRATORY RESERVE
VOLUME (ERV)
• Air that never leaves lungs = RESIDUAL VOLUME
(RV) *keeps alveoli open, approx. 1200mL)
• The passageways that retain air that never reaches
alveoli = Anatomic Dead space (approximately 150ml)
• Maximum exhalation after maximum inhalation = VITAL
CAPACITY (VC)
What factors can attribute to a large
lung capacity?
* Your lungs don’t increase in tissue or size after
adulthood, it is lung ability and cardiovascular
fitness that makes the difference.
• Gender: males have larger lungs on average
• Athletes: endurance increases
• Height: taller people have larger organs
• Hobbies: wind instruments
• Habits: non-smokers
• Environment: people living at high altitudes atm
• Age: younger vs. older
• Health: sicknesses decrease VC
Breathing Physiology
Regulation and Control
• 2 regions control involuntary
breathing: medulla and pons
– Rhythmicity
– Depth of breath
• Voluntary breathing
controlled by Cerebral Cortex
• Problems: Apnea and SIDS disruption of normal
respiratory reflex pattern
What is sleep apnea?
Pause or slowing of breathing during
sleep
Video on Sleep Apnea
Factors that Affect Breathing
• Chemical changes – carbon dioxide and
H+ ions (exercise, holding your breath)
• Inflation reflex – stretching of lung tissue
• Emotions: upset, fear, and pain,
hyperventilation
• Surfactant amounts
• Airway resistance
Gas Exchange at the Alveoli
• Gases move by diffusion.
• Each gas has its own partial pressure.
• Other chemicals
can cross the
respiratory
membrane for
Breath Analysis.
ex: alcohol and
diabetes (acetone)
Factors that Affect Gas Diffusion
• Surface area
• Distance across membranes
• Change in partial pressure
***Diseases can affect all factors above!
1. pneumonia – increase distance
2. emphysema – decrease surface area
Oxygen Transport
• Most oxygen combines with iron in hemoglobin
to form OXYHEMOGLOBIN.
• Unstable bonds so diffusion is easy.
• More oxygen is released if:
1. Carbon dioxide increases in blood.
2. Blood pH decreases
3. Blood temperature rises
**all this happens during exercise!
If not enough oxygen is being taken in…
• Hypoxia occurs – deficiency of
oxygen reaching tissues leading to
cyanosis.
– Causes: cardiac arrest, severe head
trauma, suffocation, strangulation, and
choking, as well as any instance in
which oxygen supply is deprived from
the body.
• Carbon Monoxide poisoning –
RBC’s have a greater attraction
to carry CO instead of oxygen.
Carbon Dioxide transport
• 3 Methods of Transport:
1. Dissolved into plasma
2. Form CARBAMINOHEMOGLOBIN
- binds with hemoglobin
3. Forms a BICARBONATE ION
a. CO2 reacts with H2O to form carbonic
acid. (H2CO3)
- Enzyme carbonic anhydrase speeds up reaction.
b. H2CO3 releases H+ to make HCO3(bicarbonate ion) which will travel in plasma
to lungs.
c. Reaction is reversed when at the lungs.
ILLNESSES RELATED TO THE RESPIRATORY SYSTEM
1. Cystic Fibrosis (genetic)
2. Asthma
3. Bronchitis
4. Apnea
5. Emphysema
6. Lung Cancer
7. Altitude Sickness
8. Chronic Obstructive Pulmonary Disease (COPD)
9. Sinusitis
10. Bacterial or Viral Infections (cold, flu, pneumonia)
ALTITUDE SICKNESS
Acute mountain sickness is brought on by
the combination of reduced air pressure and
lower oxygen concentration that occur at
high altitudes. Symptoms can range from
mild to life-threatening, and can affect the
nervous system, lungs, muscles, and heart.
HAPE – High Altitude Pulmonary Edema is
an abnormal build up of fluid in the air sacs
of the lungs, which leads to shortness of
breath.