anaphysio ch 15 respiratory93
TRANSCRIPT
The Respiratory System
The Respiratory System• Basic functions of the respiratory system
• Breathing (Pulmonary Ventilation) – movement of air in and out of the lungs• Inhalation (inspiration) draws gases into the lungs.• Exhalation (expiration) forces gases out of the lungs.
• Gas Conditioning – as gases pass through the nasal cavity and paransal sinuses, inhaled air becomes turbulent. The gases in the air are
• warmed to body temperature• humidified• cleaned of particulate matter
• Gas Exchange - respiration• Supplies body with oxygen• Disposes of carbon dioxide
• Produces Sounds
• Protects respiratory surfaces
• Site for olfactory sensation
Respiration
• Respiration – four distinct processes must happen• Pulmonary ventilation – moving air into and out of
the lungs
• External respiration – gas exchange between the lungs and the blood
• Transport – transport of oxygen and carbon dioxide between the lungs and tissues
• Internal respiration – gas exchange between systemic blood vessels and tissues
Functional Anatomy of the Respiratory System
• Respiratory organs• Nose, nasal cavity, and paranasal sinuses
• Pharynx, larynx, and trachea
• Bronchi and smaller branches
• Lungs and alveoli
Organs of the Respiratory System
Figure 21.1
Respiratory System
• Consists of• Respiratory muscles – diaphragm and
other muscles that promote ventilation• Respiratory zone – site of external
respiration – respiratory bronchioles, alveolar ducts, alveolar sacs, and alveoli.
• Conducting zones• Provides rigid conduits for air to
reach the sites of gas exchange• Includes nose, nasal cavity,
pharynx, trachea• Air passages undergo 23 orders of
branching in the lungs
The Nose• Provides an airway for
respiration
• Moistens and warms air
• Filters inhaled air
• Resonating chamber for speech
• Houses olfactory receptors
• Skin is thin – contains many sebaceous glands
The Nasal Cavity
• External nares – nostrils• Divided by – nasal septum• Vestibule - anterior opening • Continuous with nasopharynx• Two types of mucous membrane
• Olfactory mucosa - Near roof of nasal cavity, houses olfactory (smell) receptors
• Respiratory mucosa - Lines nasal cavity
• Epithelium is pseudostratified ciliated columnar
• Goblet cells within epithelium • Underlying layer of lamina propria
has glands that contribute to the mucus layer and blood vessels that warm the air.
• Cilia move contaminated mucus posteriorly
Nasal Cavity
Nasal Conchae
• 3 paired bony projections along the lateral walls of the nasal cavity
• Superior and middle nasal conchae - part of the ethmoid bone
• Inferior nasal conchae - separate bone
• Function - Particulate matter deflected to mucus-coated surfaces
The Paranasal Sinuses
Figure 7.11a, b
The Pharynx• Funnel-shaped passageway• Connects nasal cavity and
mouth• Shared by the digestive and
respiratory systems• Divided into three sections by
location• Nasopharynx – superior
portion, • Oropharynx – continuous
with the oral cavity• Laryngopharynx – between
the hyoid bone and the esophagus
• Type of mucosal lining changes along its length
The Nasopharynx
• Superior to the point where food enters
• Only an air passageway
• Closed off during swallowing
• Epithelium consists of ciliated pseudostratified epithelium that moves mucus
The Oropharynx
• Arch-like entranceway – fauces• Extends from soft palate to
the epiglottis• Epithelium - stratified
squamous epithelium• Two types of tonsils in the
oropharynx• Palatine tonsils – in the
lateral walls of the fauces • Lingual tonsils – covers
the posterior surface of the tongue
The Laryngopharynx
• Passageway for both food and air
• Epithelium - stratified squamous epithelium
• Continuous with the esophagus and larynx
The Larynx• Prevent food and drink from entering the trachea
• Passageway for air
• Produces Sound
• It connects the pharynx to the trachea
• Epithelium of the larynx
• Stratified squamous – superior portion
• Pseudostratified ciliated columnar – inferior portion
Nine Cartilages of the Larynx
• Thyroid cartilage - shield-shaped, forms laryngeal prominence (Adam’s apple)
• Three pairs of small cartilages
• Arytenoid cartilages
• Corniculate cartilages
• Cuneiform cartilages
• Epiglottis - tips inferiorly during swallowing
The Larynx
• Vocal ligaments of the larynx• Vocal folds (true vocal
cords) - act in sound production
• Vestibular folds (false vocal cords) - no role in sound production
• Voice production • Length of the vocal folds
changes with pitch• Loudness depends on the
force of air across the vocal folds
The Trachea• Descends into the mediastinum
• C-shaped cartilage rings keep airway open
• Carina - marks where trachea divides into two primary bronchi
• Epithelium - pseudostratified ciliated columnar
The Trachea
Figure 21.7a, b
Bronchi in the Conducting Zone• Bronchial tree - extensively
branching respiratory passageways• Primary bronchi (main
bronchi)• Largest bronchi • Right main bronchi - wider
and shorter than the left• Secondary (lobar) bronchi
• Three on the right • Two on the left
• Tertiary (segmental) bronchi - branch into each lung segment
• Bronchioles - little bronchi, less than 1 mm in diameter
• Terminal bronchioles - less than 0.5 mm in diameter
Tissue Composition of Conducting Zone
• Changes along pathway• Supportive connective tissues change
• C-shaped rings – trachea, primary bronchi• Replaced by cartilage plates, secondary & tertiary bronchi
• Epithelium changes• First, pseudostratified ciliated columnar – trachea• Replaced by simple columnar - bronchi• Then simple cuboidal epithelium - bronchioles and
terminal bronchioles • Smooth muscle becomes important at the bronchioles -
controlled by the ANS (bronchoconstriction and bronchodilation).
Lobes and Surfaces of the lungs• Right lung has three lobes
• Left lung has two lobes
• Concavity on medial surface = cardiac notch
• Bronchi enter the lungs at the hilus
The Pleurae• A double-layered sac surrounding each lung
• Parietal pleura• Visceral pleura
• Pleural cavity - potential space between the visceral and parietal pleurae• Pleurae help divide the thoracic cavity
• Central mediastinum • Two lateral pleural compartments
Structures of the Respiratory Zone
• Consists of air-exchanging structures
• Respiratory bronchioles – branch from terminal bronchioles• Lead to alveolar ducts
• Lead to alveolar sacs
Structures of the Respiratory Zone
Figure 21.9b
Features Of Alveoli
Figure 21.10b
• Alveoli cell types• Type I cells site of gas exchangeand• Type II cells - secrete surfactant• Macrophages
• Surrounded by basal laminae and elastic fibers• Interconnect by way of alveolar pores• Internal surfaces - site for free movement of alveolar macrophages
RESPIRATORY SYSTEMDISORDERS
Disorders of the Respiratory System
• Anthrax• Caused by spores of the bacterium
• Asthma attack• May result from exposure to an allergen,
cold temperature, exercise, or emotion
• Atelectasis• A collapse of part or all of a lung, caused by
a tumor in the thoracic cavity, pneumonia, or injury
Disorders of the Respiratory System (continued)
• Bronchitis• An infection of the bronchi
• Carbon monoxide poisoning• Occurs from breathing carbon monoxide
• Chronic obstructive pulmonary disease • A group of chronic respiratory disorders
including asthma, chronic bronchitis, and pulmonary emphysema
Disorders of the Respiratory System (continued)
• Cold • A respiratory infection
• Cystic fibrosis • A genetic disorder of the exocrine glands
• Emphysema • The alveoli lose elasticity and become
dilated and do not exchange gases well
Disorders of the Respiratory System (continued)
• Hantavirus • A respiratory condition spread by breathing
in materials contaminated by urine or saliva of infected rodents such as deer mice and chipmunks
• Hay fever • A respiratory inflammation caused by
allergens such as plants, dust, and food
• Lung cancer • Directly linked to smoking and smoke
products
Disorders of the Respiratory System (continued)
• Pleural effusion • A condition in which air or fluid enters the
pleural cavity
• Pleurisy• An inflammation of the membranes that line
the lungs
• Pneumonia • An inflammation of the lungs, in which a
buildup of excessive moisture impairs breathing
Disorders of the Respiratory System (continued)
• Pneumoconiosis • An inflammation in the lungs caused by
inhaled irritants
• Respiratory acidosis• A buildup of carbon dioxide in the blood,
causing a lowered blood pH
• Respiratory alkalosis • A deficiency of carbon dioxide in the blood
Disorders of the Respiratory System (continued)
• Respiratory distress syndrome
• A condition that occurs when the alveoli do not inflate properly
• Sinusitis • An inflammation of one or more of the
paranasal sinuses • Sudden infant death syndrome (SIDS)
• A respiratory disorder of newborns
Disorders of the Respiratory System (continued)
• Tuberculosis • Caused by bacteria that are difficult to
destroy, and it can be transmitted through the air
• Upper respiratory infection• Caused by a virus or bacteria in the nose,
pharynx, or larynx