RESPIRATORY SYSTEM

Function: - To supply the body with oxygen and to dispose of carbon dioxide. - acid-base balance

Includes: lungs system of tubes -- link the sites of gas exchange with the external environment VENTILATION MECHANISM consists of thoracic cage intercostal muscles diaphragm elastic & collagen components of lungs THE RESPIRATORY SYSTEM

2 PRINCIPAL REGIONS of RESPIRATORY SYSTEM A. CONDUCTING PORTION consists of nasal cavity, nasopharynx trachea, bronchi, bronchioles terminal bronchioles B. RESPIRATORY PORTION -- gas exchange takes place consists of respiratory bronchioles alveolar ducts alveolar sac or alveoli

CONDUCTING PORTION FUNCTIONS: a. To provide a conduit through which air can travel to & from the lungs b. To condition the inspired air -- major function Before air enters the lungs, inspired air is cleaned, moistened & warmed. The mucosa of the conducting portions is lined by a specialized respiratory epithelium.

NASAL CAVITY DIFFERENT STRUCTURES A. EXTERNAL VESTIBULE B. INTERNAL NASAL FOSSAE VESTIBULE - - Most anterior & dilated portion of nasal cavity - - Outer integument of the nose enters the nares (nostrils) & continuous part way up the vestibule - - Vibrissae external nose -composed mostly of cartilage Parts: bridge (upper part) - 2 small nasal bones apex - tip of the nose nares - nostrils

NASAL CAVITY = filters & moistens the incoming air Main parts: nasal fossae - separated by a cartilage & bony wall (septum) wall (septum) *nasal septum - richly supplied with sensory *nasal septum - richly supplied with sensory nerves & BVs (epistaxis originates) roof - formed by a small portion of the frontal lobe, sphenoid, & ethmoid floor - hard palate vestibule - contains stiff hairs (vibrissae) conchae / turbinates - 3 (superior, inferior, middle) thin curled bones - project inward from the outer walls thin curled bones - project inward from the outer walls -- spaces above & below each concha  meatuses -- spaces above & below each concha  meatuses

N O S E FUNCTION: = filters, warms, moistens the air entering & helps in phonation Nasal mucous membrane - epithelium: ciliated pseudostratified columnar - cilia --- wave back & forth (12 x per minute) - help mucus clean the air

N O S E Air enters the nose (specialized hairs) vibrissae - serve to remove coarse particles of dusts Once air reaches the nasal fossae  particulate & gaseous impurities are trapped in a layer of mucus  with serous secretions, also serves to moisten the incoming air protecting the delicate alveolar lining from desiccation. Incoming air  warmed by a rich superficial vascular network.

NERVE ENDINGS for the OLFACTORY NERVE - lie on the upper 3 rd of both sides of the nasal septum - Nerve fibers pass thru small holes in the ethmoid bone to the olfactory bulb, then to the cortex where the impulses are interpreted as smell / odor sneeze reflex = burning & irritation of the sensory nerve endings = inhalation of air followed by an explosive exhalation to clear the airway

DEFENSE MECHANISM of RESPIRATORY SYSTEM Particles > 10 um retained in nasal passages Particles > 10 um retained in nasal passages 2 – 10 um  trapped by the mucus - coated ciliated epithelium 2 – 10 um  trapped by the mucus - coated ciliated epithelium Cough reflex can eliminate these particles by expectoration or swallowing Cough reflex can eliminate these particles by expectoration or swallowing Smaller particles  removed by alveolar macrophages Smaller particles  removed by alveolar macrophages

Kartagener’s syndrome Syn: Immotile cilia syndrome - a disorder characterized by infertility in males & chronic respiratory infection - caused by immobility of cilia & flagella induced by deficiency of dynein.

PARANASAL SINUSES - blind cavities - frontal, maxillary, ethmoid, sphenoid FUNCTIONS: 1. lighten the bones of the skull 2. provide mucus for the nasal cavity 3. act as resonating chambers during phonation

The uppermost portion of the human respiratory system, the nose is a hollow air passage that functions in breathing and in the sense of smell. The nasal cavity moistens and warms incoming air, while small hairs and mucus filter out harmful particles and micro-organisms. This illustration depicts the interior of the human nose.

SINUSITIS - Inflammatory process of the sinus that persists for long periods of time - Due to obstruction of the orifices CHRONIC SINUSITIS - Also component of Kartagener’s syndrome

PHARYNX ( THROAT ) - Musculomembranous tube ( 5 in. long ) extending from the base of the skull  esophagus parts:nasal orallaryngeal nasopharynx - nasal; 1 st part; air only oropharynx - food, air, water laryngopharynx - not involved in respiration

LARYNX ( VOICE BOX ) - Irregular tube that connects the pharynx  trachea 3 unpaired cartilages3 paired cartilages 1. thyroid (largest) 1. arytenoid 1. thyroid (largest) 1. arytenoid 2. cricoid (signet rings) 2. cuneiform 2. cricoid (signet rings) 2. cuneiform 3. epiglottis 3. corniculate 3. epiglottis 3. corniculate Epiglottis - projects from the rim of the larynx, extends into the pharynx Below: 2 pairs of folds a. False vocal cord (respiratory epithelium) b. True vocal cord (strat. squamous epith.) - voice production

LARYNX ( VOICE BOX ) Chief function:phonation pitch of voice depends on the length & tightness of the cord loudness of voice depends on the force with which the cords vibrate quality & resonance of voice depend of the shape of the mouth, position of the tongue, lips, facial muscles, & air sinuses

TRACHEA ( WINDPIPE ) - Continuation of the larynx - Extends to approx. the level T5, where it divides or bifurcates into R & L bronchi - 16 – 20 C – shaped hyaline cartilages FUNCTION: passageway of air to reach the lungs TRACHEOTOMY - opening into the trachea TRACHEOSTOMY - trachea is exposed or a tube is placed into it to maintain patency

THE BRONCHI 1 BRONCHI R BRONCHIwider shorter tube more vertical position 2.5 cm. length divides into 3 branches after entering the lung L BRONCHInarrower 5 cm. length 5 cm. length divides into 2 branches after entering the lung

BRONCHIOLES - Smaller branches of bronchi - 1 mm. in diameter Terminal bronchioles small or minute bronchioles  form respiratory bronchioles   alveolar ducts  alveoli

ALVEOLI - Functional unit of the lung 1 Types of cells: 1. Type I cells - thin squamous epithelial cells 2. Type II cells - septal or granular pneumocytes - cuboidal epithelial cells - secretes surfactant 3. Alveolar macrophages - clear the lungs of inhaled particles that have not been eliminated by mucociliary system of the respiratory passages