Transcript Chapter One

The Respiratory
System
Elsevier items and derived items © 2009 by Saunders, an
imprint of Elsevier Inc.
Functions and Overview of
Respiration
1. Respiratory system
works with the
circulatory system
a. Provides oxygen to
the body
b. Removes waste
products of
metabolism
c. Helps to regulate
pH of the blood
Elsevier items and derived items © 2009 by Saunders, an
imprint of Elsevier Inc.
2
1. Exchanges oxygen (O2)
and carbon dioxide
(CO2) between
atmosphere and body
cells
2. 1 respiration occurs
every 3-5 seconds
3. Pons & medulla
oblongota stimulate
breathing
3. Blood transports the
gases to and from the
tissue cells
RESPIRATION
Elsevier items and derived items © 2009 by Saunders, an
imprint of Elsevier Inc.
3
Conducting Passages
1. Upper respiratory
tract: nose, pharynx,
larynx
2. Lower respiratory
tract: trachea,
bronchial tree, lungs
Elsevier items and derived items © 2009 by Saunders, an
imprint of Elsevier Inc.
4
Nose and Nasal Cavities
1. Nose-where the
respiration starts
2. Nasal cavity divided by
nasal septum.
3. Internal nares openings
from the nasal cavity into
the pharynx
4. Nasal conchae: three
bony ridges that project
into nasal cavity
Elsevier items and derived items © 2009 by Saunders, an
imprint of Elsevier Inc.
5
Oral Cavity
•
Palate: separates nasal
cavity from oral cavity
a. Hard palate: anterior
portion supported by
bone
b. Soft palate: posterior
portion, no bony support
c. Uvula: posterior
projection of the soft
palate
•
Helps direct food into
oropharynx
Elsevier items and derived items © 2009 by Saunders, an
imprint of Elsevier Inc.
6
Sinues
•
Paranasal sinuses: air-filled cavities in
frontal, maxillae, ethmoid, and sphenoid
bones
a. Surround nasal cavity and open into it
b. Functions:
•
•
•
Reduce weight of skull
Produce mucus that drains into nasal cavity
Influence voice quality: act as resonating chambers
Elsevier items and derived items © 2009 by Saunders, an
imprint of Elsevier Inc.
7
Pharynx
Pharynx
1. Commonly called the throat
2. Serves both respiratory and digestive
systems
a. Receives air from the nasal cavity
b. Receives air, food, and water from oral cavity
3. Opens into larynx and esophagus
4. Divided into three regions:
a. Nasopharynx
b. Oropharynx
c. Laryngopharynx
Elsevier items and derived items © 2009 by Saunders, an
imprint of Elsevier Inc.
8
Larynx
Larynx
1. Commonly called the voice box
2. Passageway for air between pharynx and
trachea
5. Formed by nine pieces of cartilage
6. 2 pairs of ligaments that make up false and
true vocal cords
Elsevier items and derived items © 2009 by Saunders, an
imprint of Elsevier Inc.
9
Ventilation, cont.
Elsevier items and derived items © 2009 by Saunders, an
imprint of Elsevier Inc.
10
Trachea
Trachea
1. Commonly called the windpipe
2. Tube extends from larynx to mediastinum
3. Divides into right and left bronchi
4. 15-20 C-shaped pieces of hyaline cartilage
a. Hold the trachea open
Elsevier items and derived items © 2009 by Saunders, an
imprint of Elsevier Inc.
11
Bronchi
Bronchi and Bronchial Tree
1. Trachea divides into right and left primary
bronchi
2. Enters the lungs forms the bronchial tree
3. Primary bronchi divide to form secondary
(lobar) bronchi
a. Branch into tertiary (segmental) bronchi
4. Branching continues: finally giving rise to
bronchioles
Elsevier items and derived items © 2009 by Saunders, an
imprint of Elsevier Inc.
12
Bronchioles
• Terminal bronchioles: branch into smaller
respiratory bronchioles
a. Lead into microscopic alveolar ducts
•
Terminate in clusters of tiny air sacs: alveoli
• Alveolar ducts and alveoli permits rapid
diffusion of oxygen and carbon dioxide
a. Exchange of gases between the air in the lungs
and blood in capillaries
•
Occurs across walls of alveolar ducts and alveoli
Elsevier items and derived items © 2009 by Saunders, an
imprint of Elsevier Inc.
13
Lungs
Lungs
1. Occupy most of space in thoracic cavity
2. Soft and spongy
a. Mostly air spaces surrounded by alveolar cells
and elastic connective tissue
3. Separated by mediastinum, which contains
the heart
4. Rests on the diaphragm
Elsevier items and derived items © 2009 by Saunders, an
imprint of Elsevier Inc.
14
Lungs
1. Right lung: shorter, broader, greater volume
than left lung
a. Divided into three lobes (superior, middle, and
inferior) by two fissures
2. Left lung: longer and narrower than right
lung
a. Cardiac notch: indentation on medial surface
•
For apex of heart
b. Divided into two lobes by a single fissure
Elsevier items and derived items © 2009 by Saunders, an
imprint of Elsevier Inc.
15
Lungs
Elsevier items and derived items © 2009 by Saunders, an
imprint of Elsevier Inc.
16
Pleura
• Pleura: double-layered serous membrane
that encloses the lungs
a. Visceral pleura: firmly attached to surface of
lung
b. Parietal pleura: lines the wall of the thorax
• Pleural cavity: small space between the
visceral and parietal pleura
a. Contains a thin film of serous fluid
•
Acts as a lubricant
– Reduces friction as the two layers slide against each
other
Elsevier items and derived items © 2009 by Saunders, an
imprint of Elsevier Inc.
17
The Lungs and Pleura
Elsevier items and derived items © 2009 by Saunders, an
imprint of Elsevier Inc.
18
Ventilation
1. Pulmonary ventilation: breathing
2. Air flows because of pressure
differences between atmosphere and
gases inside the lungs
3. Normal respiratory rate: 12-20 breaths
per minute
4. Consists of one inhalation and one
exhalation
5. Amount of air that is exchanged during
one cycle
a. Varies with age, sex, size, physical
condition
Elsevier items and derived items © 2009 by Saunders, an
imprint of Elsevier Inc.
19
Inhalation
Inhalation
1. Process of taking air into the lungs
2. Diaphragm: dome-shaped muscle
a. Separates thoracic cavity from abdominal
cavity
b. Contraction causes diaphragm to drop
•
Increases the size of the thoracic cavity
– Air flows from outside the body into the lungs
Elsevier items and derived items © 2009 by Saunders, an
imprint of Elsevier Inc.
20
Exhalation
Exhalation
1. Process of letting air out of the lungs
2. Diaphragm relaxes: thoracic cavity
decreases to its normal size
a. Air now flows from within the lungs to the
outside of the body until the two pressures are
equal
Elsevier items and derived items © 2009 by Saunders, an
imprint of Elsevier Inc.
21
Ventilation
External Respiration
1. Exchange of oxygen and carbon dioxide
a. Between the lungs and blood
2. Oxygen diffuses from alveoli of the
lungs into the blood (capillaries)
3. Carbon dioxide diffuses from the blood
into the alveoli
Elsevier items and derived items © 2009 by Saunders, an
imprint of Elsevier Inc.
22
Ventilation
Internal Respiration
1. Exchange of gases between the tissue
cells and the blood
2. Oxygen is given off to the cells
3. Carbon dioxide is picked up by the
blood
a. Transported as a waste product to the
lungs
Elsevier items and derived items © 2009 by Saunders, an
imprint of Elsevier Inc.
23
Regulation of Respiration
Chemoreceptors
1. Chemoreceptors in the medulla
a. Sensitive to changes in carbon dioxide
concentrations
b. Not sensitive to changes in oxygen levels
c. If carbon dioxide increases:
•
Stimulate respiratory center to increase rate and
depth of breathing
– Decrease concentrations back to normal levels
Elsevier items and derived items © 2009 by Saunders, an
imprint of Elsevier Inc.
24
Regulation of Respiration
Stimulus from Higher Brain Centers
1. Impulses from higher brain centers
a. May override respiratory center temporarily
b. Example: voluntarily holding your breath
•
•
Can do so for only a limited time
When carbon dioxide levels reach a critical point
– Impulses from higher brain centers are ignored:
respiratory center resumes regular breathing
Elsevier items and derived items © 2009 by Saunders, an
imprint of Elsevier Inc.
25
Regulation of Respiration, cont.
Nonrespiratory Air Movements
1. Reflexes that clear air passages
2. Sneezing and coughing
3. Sighing
4. Hiccuping
5. Crying
6. Laughing
7. Yawning
Elsevier items and derived items © 2009 by Saunders, an
imprint of Elsevier Inc.
26
Deviated septum
Constant
rubbing/wiping of the
nose or injury to the
nose can cause a
deviated septum.
27
Epistaxis
Nosebleeds are common and can be idiopathic,
cold/allergy related or due to nasal dryness.
28
Pleurisy
Also known as pleuritis-an inflammation of the
pleura, the lining of the pleural cavity surrounding the
lungs.
Infection most common cause.
Main symptom is sharp or stabbing pain in the chest
that gets worse with deep breathing, coughing or
sneezing.
29
Pleural Effusion
• Fluid in the
thoracic cavity
between the
visceral and
parietal pleura.
30
Rhinits
Inflammation of the
nasal mucosa.
Caused by virus,
bacteria & allergens.
31
COPD
•
•
•
•
One of the most common lung diseases
2 types: chronic bronchitis & emphysema
May have both-No cure!
Causes: Smoking #1. Exposure to gas,
fumes, smoke & pollution
• Symptoms: Develop slowly
a.Cough with mucus
b.Shortness of breath (dyspnea) that gets worse
with mild activity
c. Fatigue
d.Frequent respiratory infections
e.Wheezing
32
Tuberculosis
1. TB
2. Caused by Mycobacterium tuberculosis
3. Can lie dormant in body for years
4. May have positive TB skin test but never
develop disease
5. Increased chance to become active TB when
immune system not functioning properly
6. Preventative antibiotics for 6 months
33
Pertussis
Whooping cough, a highly
contagious bacterial infection
of the pharynx, larynx & trachea.
Explosive coughing spasms
ending in “whooping” sound.
Immunization given to protect.
Passed from adults whose
immunity worn off.
34
Pneumothorax
Accumulation of air in the pleural cavity
Collapse of the
alveoli is known
as a collapsed
lung or atelectasis.
35
36