Transcript Respiratory System

Respiratory System
Respiratory Tract
• Conducting passageways carrying air to and
from the alveoli
– Upper respiratory
• Nasal Cavity
• Larynx
• Pharynx
– Lower passageways
• Trachea
• Lungs
Pathway
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Bronchi
Bronchioles
Alveoli
Diaphragm
nasal cavities (or oral cavity) → pharynx → trachea → primary bronchi (right & left) →
secondary bronchi → tertiary bronchi → bronchioles → alveoli
Nasal Cavity/Nose
• Functions
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Provides an airway for respiration
Moistens and warms entering air
Filters and cleans inspired air
Resonating chamber for speech
Detects odors in the airstream
• Selected anatomical features
– Vibrissae (guard hairs) – stiff hairs that filter large particles from the air
– Nasal cilia – hair-like projections that propel trapped particles towards the throat
for digestion by digestive enzymes
– Rich supply of capillaries warm the inspired air
– Nasal conchae – folds in the mucous membrane that increase air turbulence and
ensures that most air contacts the mucous membranes
– Olfactory mucosa – mucous membranes that contain smell receptors
– Respiratory mucosa – pseudostratified ciliated columnar epithelium containing
goblet cells that secrete mucus
» Mucus
» Stickiness traps inhaled particles
» Lysozyme kills bacteria
– Lymphocytes and IgA antibodies protect against bacteria
Respiratory Mucosa
Upper Respiratory
Paranasal Sinuses
Pharynx
Three regions of the pharynx
•Nasopharynx – air
passage (pseudostratified
columnar epithelium)
•Oropharynx –
passageway for air, food,
and drink (stratified
squamous epithelium)
•Laryngopharynx –
passageway for air, food,
and drink (stratified
squamous epithelium)
Larynx
Functions
1. Keeps food and drink out of the airway
2. Sound production
3. Acts as a sphincter during abdominal straining (ex. during defecation and
heavy lifting)
Larynx
Selected anatomical features
•Nine c-rings of hyaline
cartilage form the framework
of the larynx
•Muscular walls aid in voice
production and the
swallowing reflex
•Glottis – the superior
opening of the larynx
•Epiglottis – prevents food
and drink from entering
airway when swallowing
•False vocal cords – aid in
closing the glottis when
swallowing
•True vocal cords – produce
sound when air passes
between them
•The shorter and thinner
these membranes are, the
faster air moves over them –
Glottis
Trachea
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Functions
1. Air passageway
2. Cleans, warms, and moistens incoming air
3. Selected anatomical features
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Rings of hyaline cartilage – reinforce the trachea
and keep it from collapsing when you inhale
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Ciliated pseudostratified epithelium – traps
inhaled debris and propels mucus up to the
pharynx where it is swallowed
Lung Anatomy
•Function - Solely an air passageway
•Selected anatomical features
1. Left and right primary bronchi branch off from trachea
2. Once the left and right primary bronchi enter the lungs they
are subdivided into smaller tubes:
Secondary bronchi (one for each lobe) → tertiary bronchi →
bronchioles → terminal bronchioles → respiratory
bronchioles → alveolar ducts → alveolar sacs
3. Alveolar sacs are clusters of alveoli
4. Alveoli are the site of gas exchange
5. Other tissue types present in the alveoli
a. Smooth muscle rings aid in resistance to air flow
b. Elastic connective tissue fibers aid in expelling
air from the lungs
Anatomy of Bronchi
Pulmonary arteriogram
Lung bronchiogram
Respiratory Physiology
Diaphragm contracts - increase thoracic cavity vl Pressure decreases - causes air to rush into lungs
Diaphragm relaxes - decrease thoracic cavity vl Pressure increases – forces air out of lungs
Inspiration
Expiration
Patterns of Breathing
• Apnea – temporary cessation of breathing (one or more skipped breaths)
• Dyspnea – labored, gasping breathing; shortness of breath
• Eupnea – Normal, relaxed, quiet breathing
• Hyperpnea – increased rate and depth of breathing in response to exercise, pain,
or other conditions
• Hyperventilation – increased pulmonary ventilation in excess of metabolic demand
• Hypoventilation – reduced pulmonary ventilation
• Orthopnea – Dyspnea that occurs when a person is lying down
• Respiratory arrest – permanent cessation of breathing
• Tachypnea – accelerated respiration
Clinical Disorders and Diseases of
the Respiratory System
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Hypoxia – deficiency of oxygen in a tissue or the inability to use oxygen
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Chronic bronchitis – cilia are immobilized and reduced in number; goblet cells increase their production of mucus
→ mucus clogs the airways and breeds infection
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Emphysema – alveolar walls break down and the surface area of the lungs is reduced
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Asthma – allergens trigger the release of histamine and other inflammatory chemicals that cause intense
bronchoconstriction. In asthma, periodic constriction of the bronchi and bronchioles makes it more difficult to
breathe in and, especially, out. Attacks of asthma can be triggered by airborne irritants such as chemical fumes
and cigarette smoke airborne particles to which the patient is allergic.
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Lung cancer –most common cancer and most common cause of cancer deaths in U.S. males. There are several
forms of lung cancer, but the most common (and most rapidly increasing) types are those involving the epithelial
cells lining the bronchi and bronchioles. Ordinarily, the lining of these airways consists of two layers of cells.
Chronic exposure to irritants causes the number of layers to increase. The ciliated and mucus-secreting cells
disappear and are replaced by a disorganized mass of cells with abnormal nuclei. If the process continues, the
growing mass penetrates the underlying basement membrane. Malignant cells can break away and be carried in
lymph and blood to other parts of the body where they may lodge and continue to proliferate. It is this metastasis
of the primary tumor that eventually kills the patient.
Oxygen toxicity – excess oxygen, causing the build up of peroxides and free radicals
Chronic obstructive pulmonary diseases (COPD) – long-term obstruction of airflow and a substantial reduction in
pulmonary ventilation
Clinical Disorders and Diseases
of the Respiratory System
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Acute rhinitis – the common cold
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Pneumonia – lower respiratory infection of the alveoli that causes fluid build up in the lungs. It can be caused by
many kinds of both bacteria (Streptococcus pneumoniae) and viruses. Tissue fluids accumulate in the alveoli
reducing the surface area exposed to air. If enough alveoli are affected, the patient may need supplemental
oxygen.
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Sleep apnea – Cessation of breathing for 10 seconds or longer during sleep
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Tuberculosis – pulmonary infection with Mycobacterium tuberculosis; reduces lung compliance
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Pleuritis - Inflammation of the pleura, producing more than the normal amount of fluid, causing a pleural effusion.
The pain fibers of the lung are located in the pleura. When this tissue becomes inflamed, it results in a sharp pain
in the chest that is worse with breathing in. Other symptoms of pleurisy can include cough, chest tenderness, and
shortness of breath.
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Cystic fibrosis - caused by inheriting two defective CFTR genes, a transmembrane protein needed for the
transport of Cl− ions out of the epithelial cells of the lung thus enabling water to follow by osmosis. Diminished
CFTR function reduces the water content of the fluid in the lungs making it more viscous and difficult for the
ciliated cells to move it up out of the lungs. The accumulation of mucus plugs the airways interfering with breathing
and causing a persistent cough. Cystic fibrosis is the most common inherited disease in the U.S. white population.
Laryngitis – inflammation of the vocal folds