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Anatomy & Physiology of
Respiratory systemAnita. F. Lopes
Principal, Uday Ger School of Nursing,CGMH
The respiratory tract is the path of air from the nose to the lungs
The organs of the respiratory system make ensure that oxygen enters our bodies and carbon dioxide leaves our bodies.
During inhalation or exhalation air is pulled towards or away from the lungs, by several cavities, tubes, and openings.
To sustain respiration the anatomical structures, neuromuscular system and the cardiovascular system should be normal.
Introduction
BREATHING or ventilation EXTERNAL RESPIRATION, which is the
exchange of gases (oxygen and carbon dioxide) between inhaled air and the blood.
INTERNAL RESPIRATION, which is the exchange of gases between the blood and tissue fluids.
CELLULAR RESPIRATION
Process of Respiration
In addition to these main processes, the respiratory system serves for:
REGULATION OF BLOOD pH, which occurs in coordination with the kidneys, and as a
'DEFENSE AGAINST MICROBES Control of body temperature due to loss
of evaporate during expiration
Parts of Respiratory Tract Upper Respiratory Tract : Nostrils, Nasal Cavities( Sinuses) Pharynx,
Lower respiratory tract: Larynx Trachea Main stem bronchi Segmental bronchi Subsegmental bronchi Bronchioles Terminal bronchioles Respiratory bronchioles Alveolar ducts Alveolar sacs Alveoli
Rigid structure composed of cartilage and bone Septal cartilage divides nasal cavity into two
nasal fossae Palate divides nasal cavity and oral cavity Nose divided into 3 regions Nares or nostrils serve as opening for the nasal
fossae—two cavities in middle of the face Vestibule/vestibular region
◦ Lined with stratified squamous epithelium◦ Contain vibrissae-nasal hair, first line of
defense, function to filter inspired air
The Nose
Filter the air Humidify the air Warm the air Site for sense of small To generate resonance in speech
The Functions of the Nose
Air-filled cavities within the skull (cranium) Paranasal sinuses (four pairs) Function not clear, lighten head and provide
voice resonance Lined with pseudo stratified ciliated
columnar epithelium and goblet cells
Sinuses
Alternate respiratory passage Anterior 2/3 of tongue located in oral cavity Another “respiratory” muscle Lined with stratified squamous epithelium
Oral Cavity
(Throat), hollow, upper portion of the airway and the digestive tract
Subdivided into: nasopharynx, oropharynx, laryngopharynx A flap-like epiglottis closes the opening to the
larynx during swallowing to prevent swallowed matter from entering the trachea.
Pharynx
STRUCTURE:• Enlargement in the airway at the top of
trachea and below pharynx• Framework of cartilage and dense
connective tissue• Glottis (triangular opening between vocal
cords)• Can be closed by Epiglottis or vocal folds• Houses true vocal cords• Connecting zone between upper
and lower airway (vocal cords and below)
Laryngopharynx
FUNCTION:• Passageway for air• Prevents foreign objects from entering trachea• Epiglottis allows air to enter the larynx and
partially covers larynx during swallowing the keep food out of air passages• Voice production
Laryngopharynx
Placement of E.T tube
Epiglottis
Trachea The trachea, or windpipe, is a
tube that connects the pharynx and larynx to the lungs, allowing the passage of air.
It is lined with pseudostratified ciliated columnar epithelium cells with goblet cells that produce mucus.
This mucus lines the cells of the trachea to trap inhaled foreign
The trachea has an inner diameter of about 25 millimetres (1 in) and a length of about 9 to 15 centimeters (4 to 6 in).
It commences at the lower border of the larynx, level with the sixth cervical vertebra, and bifurcates into the primary bronchi at the vertebral level of thoracic vertebra T5, or up to two vertebrae lower or higher, depending on breathing.
There are about fifteen to twenty incomplete C-shaped cartilaginous rings that reinforce the anterior and lateral sides of the trachea to protect and maintain the airway, leaving a membranous wall (pars membranacea) dorsally without cartilage.
The cartilaginous rings are incomplete to allow the trachea to collapse slightly so that food can pass down the esophagus.
Trachea
Series of branching airways commonly referred to a “generations” or “orders”
The first generation or order is zero (0), the trachea itself.
Bifurcates at the carina
Tracheobronchial Tree
Dichotomous branching (daughter branches)
Airways become progressively narrower, shorter, and more numerous
Cross-sectional area enlarges Common histology (at the nose) and
throughout until the bronchiole generation
Tracheobronchial Tree
Right bronchus◦ Wider◦ More vertical◦ 5 cm shorter◦ Supported by C
shaped cartilages◦ 20-30 degree angle◦ First generation
Left bronchus◦ Narrower◦ More angular◦ Longer◦ Supported by C
shaped cartilages◦ 40-60 degree angle◦ First generation
Main Stem Bronchi
R main stem divides into:◦ Upper lobar
bronchus◦ Middle lobar
bronchus◦ Lower lobar
bronchus
L main stem divides into:◦ Upper lobar
bronchus
◦ Lower lobar bronchus
Lobar Bronchi
R lobar divides into◦ Segmental bronchi◦ 10 segments on right
L lobar divides into◦ Segmental bronchi◦ 8 segments on left
Segmental Bronchi : 3rd generation
Subsegmental Bronchi: Progressively smaller airways1-4 mm diameterAt 1 mm diameter connective tissue sheath disappears
4th to 9th generations
16th to 19th generation Average diameter is 0.5 mm Cilia and mucous glands begin to disappear
totally End of the conducting airway Canals of Lambert-interconnect this
generation,provide collateral ventilation
Terminal Bronchioles
Bronchioles◦ 10-th to 15th generation◦ Cartilage is absent◦ Lamina propria is directly
connected with lung parenchyma
◦ Surrounded by spiral muscle fibers
◦ Epithelial cells are cuboidal◦ Less goblet cells and cilia◦ With no cartilage, airway
remains open due to pressure gradients
Noncartilagenous Airways
Respiratory bronchioles Acinus (aka primary acinus; aka primary
lobule)—respiratory bronchioles to the alveoli
Ducts, sacs, alveolar◦ Squamous epithelium
Gas exchange zone
Ca. 300 million alveoli Between 75 µ to 300 µ in diameter Most gas exchange takes place at
alveolar-capillary membrane
Alveoli
STRUCTURE:• soft spongy, cone-shaped
paired composite organs located within the pleural cavities of thorax
• composed primarily of alveoli and respiratory passage ways
• Stroma is fibrous elastic connective tissue allowing the lungs to recoil passively during expiration
FUNCTION:• Houses respiratory passages
smaller than the primary bronchi
LUNGS
STRUCTURE:•Serous membranes•Parietal pleura lines the thoracic cavity•Visceral pleura covers external lung surfacesFUNCTION:•Produce lubricating fluids •Compartmentalize the lungs
PLEURAE
Two Systems: Bronchial & Pulmonary
Bronchial arteries◦ Arises from aorta till
terminal bronchioles◦ Merge with pulmonary
arteries and capillaries◦ 1% of total cardiac output
(left ventricle) Also nourish
◦ Mediastinal lymph nodes◦ Pulmonary nerves◦ Some muscular pulmonary
arteries and veins◦ Portions of the esophagus◦ Visceral pleura
Blood Supply to the Pulmonary System
1/3 blood returns to right heart◦ Azygous vein◦ Hemiazygous veins◦ Intercostal veins◦ This blood comes form the first two or three
generations of bronchi.
2/3 of blood flowing to terminal bronchioles drains into pulmonary circulation via “bronchopulmonary anastomoses”
Bronchial venous system
The second source of blood to the lungs Primary purpose is to deliver blood to lungs
for gas exchange Also delivers nutrients to cells distal to
terminal bronchioles Composed of arteries, arterioles, capllaries,
venules, and veins
Pulmonary Vascular System
Lymphatic vessels remove fluids and protein molecules that leak out of the pulmonary capillaries
Transfer fluids back into the circulatory system
Lymphatic System
Lungs are innervated by parasympathetic and sympathetic motor fibers and visceral sensory fibers
These nerve fibers enter each lung through the pulmonary plexus on the lung root and run along the bronchial tubes and blood vessels in the lungs
Parasympathetic fibers constrict the air tubes and sympathetic fibers dilate them
Nerve supply of the lungs
Mechanics of breathing
Normal breathing is involuntary,
but the respiratory muscles are
voluntarily
Respiratory Center:
◦ composed of groups of neurons
in the brainstem that control
both inspiration and expiration.
◦ It has 2 areas of special
interest: Medullary rythmicity area
Pneumotaxic area
Control of breathing
Located in the medulla oblongata Includes:
The dorsal respiratory group controls the basic rhythm of inspiration through
bursting impulses that signal contraction of inspiratory muscles. These muscles steadily increase the volume of air entering the lungs
The ventral respiratory group during forceful breathing some neurons increase
inspiratory movements and others activate muscles associated with forceful expiration
MEDULLARY RHYTHMICITY AREA
located in the pons Continuously sends impulses that cause inspiratory bursts from the
dorsal respiratory group. Therefore the pneumotaxic neurons control the breathing rate. When pneumotaxic inhibition is strong, inspiratory bursts are shorter,
increasing the breathing rate. When they are weak, inspiratory bursts are longer, therefore the
breathing rate decreases.
PNEUMOTAXIC AREA
Factors Influencing Breathing Rate and Depth Peripheral chemoreceptors:
◦ found in structures called carotid bodies and aortic bodies sense changes in blood oxygen concentration.
◦ Also found in the walls of certain large arteries in the neck and thorax.
◦ When stimulated, peripheral chemoreceptors transmit impulses to respiratory center and the breathing rate increases.
Inflation reflex: Regulates the depth of breathing Occurs when lung tissues are stretched and
stimulate stretch receptors in the visceral pleura, bronchioles, and the alveoli.
Sensory impulses travel on the vagus nerves to the pneumotaxic area of the respiratory center and shorten the duration of inspiratory movements.
Prevents inflation of lungs during forceful breathing
Emotional upset such as fear and pain can alter the breathing pattern
Factors Influencing Breathing Rate and Depth
AIRWAY ASSESSMENTS 1) Condition that associated with
difficult intubation Congenital anomalies ---> Pierre
Robin syndrome , Down’s syndrome : Infection in airway-->
Retropharyngeal abscess, Epiglottitis : Tumor in oral cavity or larynx
2) Condition that associated with difficult intubation (con’t)
: Enlarge thyroid gland
trachea shift to lateral or compressed tracheal lumen
AIRWAY ASSESSMENTS
Condition that associated with difficult intubation (con’t)
: Maxillofacial ,cervical or laryngeal trauma
: Temperomandibular joint dysfunction
: Burn scar at face and neck
Morbidly obese or pregnancy
AIRWAY ASSESSMENTS
2) Interincisor gap : normal -> more than 3 cms
AIRWAY ASSESSMENT
3) Mallampati classification: Class 3,4 -> may be difficult intubation
AIRWAY ASSESSMENT
Soft palate
Uvula
AIRWAY ASSESSMENT Laryngoscopic
view
Grade 3,4 -> risk for difficult intubation
4) Thyromental distance : more than 6 cms
AIRWAY ASSESSMENT
5) Flexion and extension of neck
AIRWAY ASSESSMENT
AIRWAY ASSESSMENT6) Movement of temperomandibular joint
(TMJ)
Grinding
THANK YOU