Transcript Structure of the alveoli

HS 130 Anatomy & Physiology II
Unit 4 Seminar
Chapter 14
The Respiratory System
Tonight’s Agenda
•Welcome
•Questions, Problems,
Concerns
•Seminar Discussion
•Announcements
Functions of The Respiratory System
•
•
•
•
Air distributor
Gas exchanger
Homeostatic mechanism
Filters, warms, and humidifies air for
breathing
• Speech and sound production
• Olfaction
Structure of The Respiratory System
• Upper respiratory tract
 Nose
 Pharynx
 Larynx
• Lower respiratory tract
 Trachea
 Bronchial tree
 Lungs
Structure of The Respiratory System
• Inverted tree (trachea to alveoli)
• Structure of the alveoli
 Single-cell outer layer less than 1 micron thick
(respiratory membrane)
 Numerous—provide an extremely large surface area
for gas exchange to occur
• Function of the alveoli
 Distribute air in close proximity to blood capillaries
in order for gas exchange to occur (diffusion)
Respiratory Mucosa
•
•
•
Specialized membrane that lines the air
distribution tubes in the respiratory tree
Covered with mucous—“mucous blanket”
 Air purification and filtration function
 More than 125 ml of mucus produced each
day
Cilia
 Move in one direction toward the
pharynx
Why is it important that the cilia move only in one direction?
What is the primary function of the cilia?
Respiratory Organs
Nose
•
•
Structure
 Nasal septum separates interior of nose
into two cavities
 Mucous membrane lines nose
 Frontal, maxillary, sphenoidal, and
ethmoidal sinuses drain into nose
Function
 Warms and moistens inhaled air
 Conchae
 Contains sense organs of smell
 12.5 cm (5 inches)
long
 Three segments
 Nasopharynx
 Oropharynx
 Laryngopharynx
 Lined by mucous
membrane
 Two sinuses, mouth, esophagus, larynx,
and auditory (eustachian) tubes all have
openings into pharynx
• Tonsils
 Pharyngeal tonsils (adenoids) are
located in the nasopharynx
 Palatine tonsils are located in the
oropharynx
Respiratory Organs
Pharynx
•
Functions
 Digestive and
respiratory
systems
 Passageway
for food and
liquids to the
esophagus
 Passageway
for air to the
respiratory
tree
Respiratory Organs
Larynx
•
•
Structure
 Several pieces of cartilage form framework
 Thyroid cartilage (Adam’s apple) is largest
 Epiglottis partially covers opening into
larynx
 Mucous lining
 Vocal cords stretch across interior of larynx
Functions
 Air distribution; passageway for air to move
to and from lungs
 Voice production
Someone you know has vomited while in an
alcohol-induced sleep and now seems to be
having great difficulty breathing. What do
you suppose has caused this? Is this person
also in respiratory distress?
Respiratory Organs
Trachea
•
Structure
 Tube about 11
cm (4.5 inches)
long extends
from larynx to
the bronchi
 C-shaped rings
of cartilage
hold trachea
open
 Mucous lining
 Ciliated
epithelium
Respiratory Organs
Trachea
•
•
Function
 Passageway for air to move to and from
lungs
Obstruction
 Complete occlusion of the airway causes
death in minutes
 4000+ deaths annually in the United
States due to tracheal obstruction
 Heimlich maneuver
Under what circumstances might the trachea
become blocked?
Respiratory Organs
Bronchi, Bronchioles, and Alveoli
•
Structure
 Right and left bronchi (primary bronchi)
 Trachea branches into right and left bronchi
 Bronchioles
 Each bronchus branches into increasingly smaller
tubes leading to bronchioles
 Alveolar sacs
 Bronchioles end in clusters of microscopic alveolar
sacs
 Alveoli
 Located in the walls of the alveolar sacs
 Millions of alveoli per lung
What structural feature keeps the bronchi open?
•
Function
 Bronchi and
bronchioles
 Air distribution
to alveoli
 Alveoli
 Exchange of
gases between
air and blood
 Thin walled
 Direct contact
with blood
capillary
 Surfactant
Respiratory Organs
Lungs and Pleura
•
Structure of lungs
 Right lung: Three
lobes
 Left lung: Two lobes
 Apex: Narrow
upper part of each
lung, under
collarbone
 Base
 Broad lower part
of each lung
 Rests on
diaphragm
•
•
Structure of the pleura
 Moist, smooth, slippery membrane that
lines chest cavity and covers outer surface
of lungs
 Parietal: Lines walls of thoracic cavity
 Visceral: Covers lungs
 Intrapleural space: Lies between parietal
and visceral
Function
 Pulmonary ventilation (breathing)
 Reduces friction between the lungs and
chest wall during breathing
Respiration
•
•
•
Mechanics of breathing (pulmonary
ventilation)
 Inspiration: movement of air into
lungs
 Expiration: movement of air out of
lungs
Changes in size and shape of thorax
cause changes in air pressure within the
thoracic cavity and the lungs
Air pressure differences actually cause
air to move into and out of the lungs
•
Inspiration
 Inspiratory muscles:
 Diaphragm: Flattens during
inspiration; increases top-to-bottom
length of thorax
 External intercostals: Contraction
elevates ribs and increases size of
thorax from front to back and from
side to side
 Increase in size of chest cavity
reduces pressure within, and air
enters the lungs
•
Expiration
 Passive process—air moves out of lungs
 During expiration, thorax returns to its
resting size and shape
 Elastic recoil of lung tissues aids in
expiration
What is the most important muscle of inspiration?
Gas Exchange in the Lungs
•
•
Route of blood flow
 Right ventricle  pulmonary artery 
lungs  lung capillaries
Mechanism
 Close proximity of capillaries in the lungs
allows exchange of gases between blood
and alveoli by diffusion
 Diffusion: Passive movement down a
concentration gradient
Oxygen  bloodstream
Carbon dioxide  alveoli
•
Internal respiration
 Oxygen moves out of tissue capillary
blood into tissue cells
 Oxyhemoglobin breaks down into
oxygen and hemoglobin
 Carbon dioxide moves from tissue cells
into tissue capillary blood
 Hemoglobin combines with carbon
dioxide, forming carbaminohemoglobin
Regulation of Respiration
•
•
Permits the body to adjust to varying
demands for oxygen supply and carbon
dioxide removal
Respiratory control centers simulate
muscles of respiratory system with nervous
impulses
 Medulla
 Inspiratory center
 Expiratory center
 Pons
 Exerts a modifying effect
•
•
Cerebral cortex
 Individual can change respiration
characteristics voluntarily (singing,
swimming, blowing balloon, etc.)
Receptors
 Chemoreceptors
 Located in carotid and aortic bodies
 Pulmonary stretch receptors
 Located throughout the pulmonary
airways including the alveoli
Respiratory Disorders and Diseases

Infections
 Acute Bronchitis
 Tracheobronchitis
 Pneumonia
 Tuberculosis
 Restrictive diseases
 Pulmonary Fibrosis
 Pneumocon-ioses
 Obstructive diseases
 Chronic Bronchitis
 Asthma
 Emphysema
Announcements
•Reminder: Initial discussion board posts should
be minimum of 150 words and responses to
classmates should be 75 words. You should respond
to classmates on a minimum of two separate days
per week.
•Final Project Outline will be due at the end of
Unit 6
•Outline: In a properly formatted document, submit an
outline. In general, an outline will help you to organize
your thoughts for your final paper. You will roughly
organize your thoughts to produce an outline that will
give you direction with regard to your reading and note
taking.
•The outline should be at least one and 1⁄2 (1.5) pages
Thanks for attending!
I’ll “see” everyone on the discussion
boards!