2 21 2020 More on the Respiratory System 1 The mucous membrane of the respiratory system a Respiratory system lined with mucous membrane mucosae i Mucous membranes line body cavities that are open to the exterior ii Consists of an epithelium and underlying connective tissue 1 Often adapted for absorption and secretion iii Secretes mucus b Not all mucous is bad mucus It clears debris and filters foreign materials entering lungs 2 Review of epithelial tissue a Sheets of cells that covers body surfaces b All epithelial tissues have two names First name indicates number of cell layers i i i ii iii iv i ii ii Second name indicates shape 1 Simple 2 Stratified 1 Squamous a Scale like 2 Cuboidal a Cube like 3 Columnar a Tall column like c Simple squamous epithelium Single layer of flattened cells Central nuclei sparse cytoplasm Function allows materials to pass by diffusion and filtration Sites endothelium alveoli etc d Stratified squamous epithelium Several cell layers Basal layer may be cuboidal or columnar 1 Active undergo mitosis to produce more surface cells iii Surface cells are flattened 1 Squamous 2 Often dead a Unable to undergo mitosis Function protects underlying tissues 3 4 Location esophagus mouth skin epidermis e Pseudostratified columnar epithelium i ii Cells vary in height Cells appear to be multi layered and stratified but only single layer simple epithelium 1 Many cells are ciliated Involved in secretion particularly of mucus iii iv Moves mucus via ciliary sweeping acting v Located mainly in the upper respiratory tract ducts of large glands and tubules in testes 3 The respiratory mucosa a Composed of 3 layers i Mucosa 1 Epithelium a Pseudostratified columnar epithelium i Ciliated b Goblet cells i Mucus 2 Lamina propria a Connective tissue ii Submucosa 1 Connective tissue and smooth muscle a Contains glands and blood vessels 2 Containing seromucous glands a Secretes mucus iii Adventitia 1 Connective tissue 4 Major respiratory organs a Supports and binds organs to others a Upper respiratory system i Nose 1 2 Nasal cavity a hollow space behind the nose that air flows External nose through 3 Nasal cavity a Septum a thin wall made of cartilage and bone that divides the inside of the nose into two chambers formed anteriorly by septal cartilage and posteriorly by vomer bone i b Bones ethmoid and sphenoid roof and palate floor separates nasal from oral cavities i Palate 1 Hard palate made of palatine bones and maxillary processes 2 Soft palate unsupported by bone and made of muscle uvula a Nasal vestibule containing sebaceous and sweat glands and hairs called vibrissae i ii Contains olfactory mucosa with olfactory nerves and receptors Contains respiratory mucosa with goblet cells secretes mucus and seromucous nasal glands that secrete enzymes b Conchae turbinates c Meatuses Filter air i ii Warm moisten incoming air iii Reclaim heat and moisture during expiration 4 Only external part of the respiratory system 5 Functions include a First site of respiration b Moistens and warms air Filters inspired air c d Has olfactory receptors 6 Jutting external portions is supported by bone and cartilage Internal nasal cavity is divided by midline nasal septum and lined with mucosa a Produces mucus filters warms and moistens incoming air resonance chamber of speech b Receptors for sense of smell ii Paranasal sinuses 1 Lighten skill a Relieves pressure 2 Warm moisten air 3 Produce additional mucus 4 Mucosa lined air filled cavities in cranial bones surrounding nasal cavities iii Pharynx 1 2 The throat Funnel shaped muscular tube a Base of skull to vertebra C6 b Connects nasal cavity and mouth to larynx and esophagus 3 3 regions a Nasopharynx b Oropharynx c Laryngopharynx 4 Passageway connecting nasal cavity to larynx and oral cavity to esophagus Houses tonsils a Passageway to air and food b Facilitates exposure of immune system to inhaled antigens b Lower respiratory system i Larynx 1 Voice box 2 Made up of 9 types of cartilage a 8 hyaline b 1 elastic epiglottis 3 Opens into laryngopharynx and is continuous with trachea 4 Functions a Voice production i ii iii Glottis opening between vocal folds Vocal ligaments true vocal chords Folds vibrate to produce sound as air rushes up from lungs b Provide a route to the lungs an airway c Route air and food into their right passageways 5 Epiglottis a Elastic cartilage i ii Allows for route to lungs Prevents aspiration