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How much do you know about The Respiratory System Website friendly

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What does the Respiratory System do? The respiratory system. Oversees gas exchanges between the blood and external environment Exchange of gasses takes place within the lungs in the alveoli Passageways to the lungs purify, warm, and humidify the incoming air

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Structures of the Respiratory System The Nasal Cavity The Oral Cavity Pharynx aka the throat Epigottis aka the guardian of the airways Larynx aka the voice box Trachea aka the windpipe Bronchi Bronchioli Alveoli

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4 the nose nares the nasal cavity conchae the palate the sinuses

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5 The Nose Provides airway entry (nares) Inflammation of the nasal mucosa is called rhinitis.

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6 Nasal cavity Olfactory receptors located in mucosa on superior surface. Nasal septum divides nasal cavity in midline Connects with pharynx posteriorly through nasopharynx

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7 Nasal cavity Lateral walls have projections called Conchae Increases surface area Increases air turbulence within the nasal cavity Resonating chamber for speech The nasal cavity is separated from the oral cavity by the Palate Anterior hard palate (bone) Posterior soft palate (muscle)

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8 Nasal Conchae Increases turbulence of air 3 scroll-like structures Reclaims moisture on the way out

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9 Paranasal sinuses (open cavities w/in bones around nose) Frontal, sphenoid, ethmoid and maxillary bones Lined by same mucosa as nasal cavity Functions: Lighten the skull, Act as resonance chambers for speech, Moisten air, & Produce mucus that drains into the nasal cavity

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10 Respiratory Mucosa Pseudostratified ciliated columnar epithelium with goblet cells. goblet cells secrete mucous Serous cells secrete watery fluid with antibiotic enzymes, e.g. lysozyme Cilia move the mucus toward the pharynx for swallowing. Even when you're healthy, your body makes about a quart of mucus/day. Most of that mucus trickles down your throat and you don't even notice it.

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the pharynx tonsils the larynx epiglottis the trachea C rings Anatomy of the Respiratory System

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12 The Pharynx (throat) Muscular passage from nasal cavity to larynx Three regions of the pharynx Nasopharynx superior region behind nasal cavity Oropharynx middle region behind mouth Laryngopharynx inferior region attached to larynx The oropharynx and laryngopharynx are common passageways for air and food

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13 The Pharynx (throat) Houses tonsils (they respond to inhaled antigens) Uvula closes off nasopharynx during swallowing so food doesnt go into nose Epiglottis (guardian of the airway) posterior to the tongue: keeps food out of airway Lined with stratified squamous epithelium for protection Intrenal Auditory tube enters the nasopharynx Tonsils of the pharynx Pharyngeal tonsil (adenoids) in the nasopharynx Palatine tonsils in the oropharynx Lingual tonsils at the base of the tongue

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14 The Larynx (voicebox) Approx. same level as 4 th - 6 th cervical vertebrae Attaches to hyoid bone superiorly Three functions: 1.Produces vibrations resulting in speech. {true vocal cords} 2.Provides an open airway (breathing) 3.Switching mechanism to route air and food into proper channels Closed during swallowing Open during breathing

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15 Framework of the larynx 8 cartilages connected by membranes and ligaments Thyroid cartilage with laryngeal prominence (Adams apple) anteriorly Cricoid cartilage inferior to thyroid cartilage: the only complete ring of cartilage: signet shaped and wide posteriorly

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16 Epiglottis Elastic cartilage attached to thyroid Cartilage of larynx. Seen @ back of tongue During swallowing, it flips inferiorly to cover and seal laryngeal opening. Keeps food out of lower respiratory tract * Posterior views

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17 Vocal cords (vocal folds) Vibrate with expelled air to create sound (speech) Glottis opening between vocal cords

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18 Trachea (the windpipe) Connects larynx with bronchi 16-20 C -shaped rings of hyaline cartilage joined by fibroelastic connective tissue Flexible for bending but stays open despite pressure changes during breathing

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19 Trachea Lined with ciliated mucosa that beat continuously in the opposite direction of incoming air to expel mucus loaded with dust and other debris away from lungs Carina-Ridge on internal aspect of last tracheal cartilage Divides into two main (primary) bronchi Surgical opening of the trachea is called a tracheostomy.

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20 Primary Bronchi Formed by division of the trachea Enters the lung at the hilus (medial depression) Right bronchus is wider, shorter, & straighter than left Bronchi subdivide into smaller & smaller branches secondary & tertiary bronchi Rt. bronchus is more common site for an inhaled object to get lodged.

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Primary bronchi Secondary bronchi Tertiary bronchi Bronchioli Terminal bronchioli Respiratory Tree Divisions

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Bronchioles Smallest branches of the bronchi All but the smallest branches have reinforcing cartilage

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Bronchioles Terminal bronchioles end in alveoli

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24 Alveoli air sacs are specialized for optimal diffusion moist membrane large surface area thin walls for diffusion (1 cell thick) - next to pulmonary capillaries, which are also 1 cell thick for gas exchange. - the inner surface of the alveoli are covered with a single layer of lipid called surfactant

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25 Surfactant Surfactant reduces the surface tension in the alveoli allowing them to easily expand to twice their size with each breath it decreases tension b/w the pleural walls. Aids in the expansion of the alveoli Made of cuboidal epithelial cells are scattered in alveolar walls Without it the walls would stick together during exhalation

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Surfactant in Babies The first cry of new born is done without the aid of surfactant The 1 st breath immediately activates body to secrete the surfactant & breathing is easier. Premature babies problem breathing is difficult because lack surfactant. Breathing is assisted until the babys lungs fully develop.

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27 Lungs (made up of the many subdivisions of the bronchi, bronchioli, & millions of alveoli) Each is cone-shaped with anterior, lateral and posterior surfaces contacting ribs 3 lobes on the right 2 lobes on the left Apex is near the clavicle (superior portion) Base rests on the diaphragm (inferior portion)

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28 Hilus or (hilum) Indentation on medial surface Place where blood vessels, bronchi, lymph vessel, and nerves enter and exit the lung Smallest subdivision seen with the naked eye is the lobule Medial view R lungMedial view of L lung

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Coverings of the Lungs Around each lung is a flattened sac of serous membrane called pleura Parietal pleura (outer layer) lines the walls of the thoracic cavity Visceral pleura directly on lung

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Coverings of the Lungs Pleural fluid fills the area between layers of pleura to allow gliding (like film between 2 plates of glass). Pleura cling to thoracic wall and are forced to expand and recoil as volume of thoracic cavity changes during breathing Pleurisy is the swelling/irritation of the pleura.

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31 Lungs and Pleura Pleural cavity divides thoracic cavity in three parts: Right & left pleural cavities, & mediastinal cavity.

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32 The Respiratory Organs Conducting zone Respiratory passages that carry air to the site of gas exchange Filters, humidifies and warms air Respiratory zone Site of gas exchange Composed of Respiratory bronchioles Alveolar ducts Alveolar sacs Conducting zone labeled

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33 Respiratory Zone End-point of respiratory tree Gas exchange occurs in the alveoli There are more than 300 million alveoli making up the lungs

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34 Respiration Pulmonary ventilation Air moves in and out of lungs Continuous replacement of gases in alveoli (air sacs) External respiration Gas exchange between pulmonary blood and air at alveoli O2 (oxygen) in air diffuses into blood CO2 (carbon dioxide) in blood diffuses into air Transport of respiratory gases Performed by the cardiovascular system Blood is the transporting fluid Occurs b/w the lungs and the body tissues Internal respiration Gas exchange in capillaries between blood and tissue cells O2 in blood diffuses into systemic tissues CO2 waste in systemic tissues diffuses into blood Gas Exchange & Transport

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36 Cellular Respiration metabolic process occurring @ the cellular level in which ATP is produced from the combination of glucose & oxygen. C 6 H 12 O 6 + 6O 2 6CO 2 + 6H 2 O + 34ATP All body cells Carbon dioxide (CO 2 ) is produced as a waste product The bodys cells die if either the respiratory or cardiovascular system fails

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37 Ventilation Breathing = pulmonary ventilation Pulmonary means related to the lungs Ventilation is air movement Two phases 1. Inspiration =inhalation-air in diaphragm and intercostal muscles contract thoracic cavity expands 2. Expiration =exhalation -air out diaphragm and intercostal muscles relax thoracic cavity shrinks

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38 Ventilation Mechanical forces cause ventilation requires energy. Diffusion of gases always flow from area of higher pressure to areas of low pressure. For air to enter the chest, the pressure of the air in the lungs has to be lower than atmospheric pressure.

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39 Muscles of Inspiration During inspiration, the dome shaped diaphragm flattens as it contracts This increases the height of the thoracic cavity The external intercostal muscles contract to raise the ribs This increases the circumference of the thoracic cavity Together:

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40 Inspiration continued Diaphragm and intercostal muscles contract The size of the thoracic cavity increases External air is pulled into the lungs due to an increase in intrapulmonary volume

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Expiration Largely a passive process which depends on natural lung elasticity As muscles relax, air is pushed out of the lungs Forced expiration can occur mostly by contracting internal intercostal muscles to depress the rib cage

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42 Expiration Rib cage drops under force of gravity Relaxing diaphragm moves superiorly (up) Elastic fibers in lung recoil Volumes of thorax and lungs decrease simultaneously, increasing the pressure Air is forced out

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43 Expiration continued Forced expiration is active process Contraction of abdominal wall muscles Internal & External Oblique & Transverse Abdomenus Increases intra-abdominal pressure forcing the diaphragm upward. Depressing the rib cage, decreases thoracic volume (try this on yourself to feel the different muscles acting)

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Pressure Differences in the Thoracic Cavity Normal pressure within the pleural space is always negative negative feedback system Differences in lung and pleural space pressures keep lungs from collapsing

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Factors Influencing Respiratory Rate and Depth Chemical factors Carbon dioxide levels Level of carbon dioxide in the blood is the main regulatory chemical for respiration Increased carbon dioxide increases respiration Changes in carbon dioxide act directly on the medulla oblongata

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Factors Influencing Respiratory Rate and Depth Chemical factors (continued) Oxygen levels Changes in oxygen concentration in the blood are detected by chemoreceptors in the aorta and carotid artery Information is sent to the medulla oblongata

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Carbon Dioxide is transported three ways in the blood 7% dissolved in the blood plasma 23% carried on the hemoglobin molecule as carbaminohemoglobin (HbCO 2 ) 70% is carried as carbonic acid/carbonate ion equilibrium

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Non-respiratory Air Movements Can be caused by reflexes or voluntary actions Examples Cough (clears the lower respiratory passage) Sneeze (uvula closes the oral cavity off from pharynx in order to clear upper respiratory passage). Laughing Crying (involves release of air in # of short breaths, similar to laughing) Yawn (formerly believed to be triggered by low O 2 ) Hiccup (sudden inspiration due to diaphragm spasms)

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Respiratory Volumes and Capacities Normal breathing moves about 500 ml of air with each breath (tidal volume [TV]) {normal quiet breathing} Many factors that affect respiratory capacity A persons size Sex Age Physical condition Residual volume of air after exhalation, about 1200 ml of air remains in the lungs

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Respiratory Volumes and Capacities Inspiratory reserve volume (IRV) Amount of air that can be taken in forcibly over the tidal volume Usually between 2100 and 3200 ml Expiratory reserve volume (ERV) Amount of air that can be forcibly exhaled Approximately 1200 ml

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Respiratory Volumes and Capacities Residual volume Air remaining in lung after expiration About 1200 ml

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Respiratory Volumes and Capacities Vital capacity The total amount of exchangeable air Vital capacity = TV + IRV + ERV Dead space volume Air that remains in conducting zone and never reaches alveoli About 150 ml

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Respiratory Volumes and Capacities Functional volume Air that actually reaches the respiratory zone Usually about 350 ml Respiratory capacities are measured with a spirometer

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54 This air-blood barrier is where gas exchange occurs. The respiratory membrane is also called the air-blood barrier. Oxygen diffuses from air in alveolus into pulmonary blood in capillary Carbon dioxide diffuses from the pulmonary blood in the capillary into the air in the alveolus

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Air Flow 1. Nose & Mouth 2. Pharynx (the 3 parts of the pharynx) nasopharynx oropharynx laryngeopharynx 3. Larynx 4. Trachea 5. Primary bronchi (right & left) 6. Secondary bronchi (aka. Bronchiole) 7. Tertiary bronchi (aka. Bronchiole) 8. Alveoli

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Respiratory Rate Changes Throughout Life Newborns (neo-6 wks) 30 60 breath/min Infants (6wk 6mo) 25-40 br/min Toddler (1- 3 yrs) 20-30 br/min Young Children (3 6 yrs) 20 25 br/min Older Children (10 14yrs) 15 20 br/min Adults 15 & up 12 20 br/min Rate often increases somewhat with old age

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Extra Credit Ideas 1.Create a 3-d model of the respiratory system out of gummy life savers & other food items @ home. Label each structures & indicate if it is part of the conducting or respiratory zone. 2.Make a working lung model out of a plastic bottle, balloons, & straws. Explain how it works. 3.Label the respiratory system on a turtle neck shirt.