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Chapter 14 - Respiratory System

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1 Chapter 14 - Respiratory System
Ensures O2 gets to cells & CO2 removed from cells, helps maintain a constant environment in the body Organs - designed to perform 2 basic functions: Air Distributor - Gas Exchanger - Also -filters, warms, humidifies air Sinuses - speech, sound, smell (olfaction)

2 Alveoli - thin-walled sacs at end of tubes where gas is exchanged
Structural Plan - Basic structure is like a many branched tube (respiratory tree) - nose, pharynx, larynx, trachea, bronchi, lungs Alveoli - thin-walled sacs at end of tubes where gas is exchanged Millions in each lung - > surface area Each is covered with a network of capillaries (like a hairnet), also, wall is single layer thick Gases (O2 & CO2) are exchanged by passive diffusion through the respiratory membrane (very thin - 1 micron thick)

3 Divided to assist in description of symptoms associated w/ problems
Respiratory Tract - Divided to assist in description of symptoms associated w/ problems Upper - nose, pharynx, larynx (URI - head cold) Located outside thoracic cavity Lower - trachea, all parts of the bronchial tree, & lungs (LRI - chest cold) Located inside thoracic cavity

4 Mucous blanket - continuous sheet
Respiratory Mucosa - Membranes that lines most of the distribution tubes Air entering nose - contaminated w/ irritants (insects, dust, pollens, bacteria) Mucous acts as most important air purification mechanism, traps almost everything < air to alveoli 125ml mucous / day Mucous blanket - continuous sheet Moved upward to pharynx by cilia that cover epithelial cells (beat one way) [smoking-paralyze]

5 Nose - External nares (nostrils) air enters & moves to R & L nasal cavities (lined w/ mucosa), parititioned by nasal septum Surface - moist (mucous), warm (many blood vessels), olfactory receptors that are nerve endings (sense of smell) Paranasal sinuses - continuous mucosa (4- frontal, maxillary, sphenoidal, ethmodial) all drain into the nasal cavities, hollow help lighten skull & serve as resonant chambers for production of sound

6 Lacrimal sacs - two ducts located inner aspect of eyes, drain tears into nasal cavity
Conchae (KONG-kee) - three shelf-like structures that protrude into the nasal cavity (both sides) Mucosa-covered > Surface area to warm and humidify Supplemental O2 - bubbled thur water to humidify (if not dries & irritates resp. tract)

7 Called the throat - about 5 inches long 3 portions -
Pharynx - Called the throat - about 5 inches long 3 portions - Nasopharynx - upper part, behind nose - contain auditory (eustachian) tubes which connect to middle ear (equalizes air pressure between middle & exterior ear), continuous mucosa (infections) Oropharynx -behind mouth Laryngopharynx - lowest portion Serves as passage of air (shared w/ GI)

8 Masses of lympathic tissue in pharynx Pharyngeal tonsils - nasopharynx
Called adenoids if swollen, make breathing thru nose difficult Palatine tonsils - oropharynx Tonsillectomy - removal of tonsils Tonsillitis - inflammation

9 Larynx - voice box (just below pharynx)
Made of cartilage (largest - thyroid cartilage - Adam’s apple) Vocal cords - 2 fibrous bands, stretch across interior of larynx Muscles cause them to tense (high pitched) & relax (low pitched) Glottis - space between vocal cords Epiglottis - cartilage, partially covers the opening of larynx (trapdoor), closed when swallowing

10 Windpipe - 4 1/2 inches long
Trachea - Windpipe - 4 1/2 inches long From larynx to bronchi Lined with mucous membrane Vital function - furnishes open airway Considerable force to squeeze closed Almost Noncollapsible material - 15 to 20 C-shaped cartilage, stacked (soft tissue between) Obstructed by: tumors, enlarged lymph nodes, aspirate food (choking-5th leading cause of accidental death in US)- Heimlich Maneuver - open windpipe that is suddenly obstructed

11 Bronchi, Bronchioles, & Alveoli -
Upside down tree (bronchial tree) Larger tubes are ringed with cartilage Primary bronchi -R & L >R & L lungs Secondary bronchi - branches in each lung Divide into smaller & smaller tubes - ultimately into tiny tubes made of smooth muscle - bronchioles > divide into microscopic tubes - alveolar ducts end in several alveolar sacs (cluster of grapes)

12 Alveoli - very effective in gas exchange
Alveolar sacs - (cluster of grapes) - each cluster made up of numerous alveoli (single grape) Alveoli - very effective in gas exchange Thin walled, each in contact w/ blood capillary Surfactant - substance that covers the resp. membrane in the alveoli Helps reduce surface tension > keeps alveoli from collapsing as air moves in & out

13 IRDS (Infant resp. distress syndrome) -
Premature infants (< 37 weeks gestation or wt. < 5 lbs. at birth), sacs collapse during expiration - inspiration requires more force to reinflate > labored breathing Lungs & Pleura – R - three lobes L - two lobes Apex - upper end toward collarbone Base - of lungs rest on diaphragm

14 Pleura - serous membrane linings, thin, moist, slippery
Parietal pleura - lines walls of thorax Visceral pleura - covers the lungs Intrapleural space - between , small amt. fluid Pleurisy - inflammation of parietal pleural Difficulty breathing, stabbing pain (rubs) Caused by infection, tumors, etc. Atelectasis - collapse of the lung > effective breathing due to < ventilation Pneumothorax - Hemothorax

15 Respiration - Exchange of gases between living organism & environment - Pair of lungs - place where air & circulating fluids (blood) can exchange gases Pulmonary ventilation - (breathing) air in & out of lungs (external respiration- exchange gases) Internal respiration - exchange gases between blood & cells Cellular respiration - use of O2 by cells Mechanisms of Breathing - Pulmonary Ventilation - 2 phases (inspiration - expiration) Changes in pressure cause movement of air in-out

16 Inspiratory muscles - Diaphragm & external intercostals
Lungs inside thoracic cavity - changes in shape & size of cavity (by muscles)- changes air pressure w/in cavity Air moves from area of high pressure to area of low pressure Inspiration - occurs when chest cavity enlarges > lungs expand > air rushes in & down to alveoli Inspiratory muscles - Diaphragm & external intercostals When these muscles contract > ^ volume in cavity > which < pressure - draws air in

17 External Intercostal -
Diaphragm - Most important muscle of inspiration Dome-shaped muscle Flattens (contract) during inspiration > cavity elongate (top to bottom) Phrenic nerve - stimulates to contract External Intercostal - Between the ribs When contract > enlarge cavity (front to back) ( side to side) > < pressure (air rushes in)

18 Expiration - ordinarily passive process (quiet expiration)
Begins as inspiratory muscles relax Cavity returns to smaller size Lungs recoil - elastic nature < in size as air leaves Expiratory muscles - used when speaking, sing, do heavy work Need more forceful expiration to > depth & rate of ventilation Internal intercostals & abdominal muscles Cavity size < & pressure w/in > & air flows out

19 Internal Intercostals Muscles- Abdominal Muscles -
Depress the rib cage < cavity size front - back Abdominal Muscles - Contract & push abd. organs against underside of diaphragm(^ dome-shape) Shortens top to bottom thoracic size Exchange of Gases in Lungs - Blood from R ventricle into pulmonary artery to lungs > tiny capillary beds close to alveoli Diffusion occurs between tiny capillaries & alveoli (O2 & CO2)

20 Exchange of Gases in Tissues -
Movement of substances from high concentration to area of low concentration Oxyhemoglobin - O2 & hemoglobin combination in RBCs (to be carried to cells) Most CO2 carried to lungs as bicarbonate ion (HCO3) , some carried in RBCs as carbaminohemoglobin Exchange of Gases in Tissues - Internal respiration - diffusion Oxyhemoglobin breaks down > O2 into cells (used) - CO2 out of cells

21 Volumes of Air Exchanged in Pulmonary Ventilation -
Spirometer - device used to measure amt. air exchanged in breathing Tidal Volume (TV) - (like ocean tides) amt. of air that comes & goes regularly Normal Inspiration ml (one pint) Normal Expiration - equal amt. Vital Capacity (VC) - largest amt. air we can breathe out in one expiration Normal young adult = 4800 ml

22 Expiratory Reserve Volume (ERV) -
Amount of air forcibly exhaled after tidal volume Inspiratory Reserve Volume (IRV) - Amount of air forcibly inspired over & above a normal resp. As TV (normal breath) >, ERV & IRV < (reserve spaces) VC = TV + IRV + ERV Residual Volume (RV) - Air that remains in lungs after most forceful expiration

23 Regulation of Respiration -
Need for O2 > as activity > (make more waste products > removed) Take more breaths (^ rate) & > tidal volume (depth) Automatic adjustments - in resp. & circulation (heart pumps faster & harder) Respiratory control centers - medulla & pons of brain - they stimulate resp. muscles Receptors sense: Changes in O2 & CO2 levels in blood, Acid levels, Amt. stretch in lungs > change resp. rate & depth

24 Cerebral Cortex - Modifying effect on inspiratory & expiratory centers of the medulla Voluntarily change pattern of breathing Hold breath (swimming, speaking, eating) As limits - resume breathing when our bodies need O2 or has too much CO2

25 Receptors Influencing Respiration -
Chemoreceptors -in carotid & aortic bodies Sense > CO2, < O2, acid levels in blood Send nerve impulses to resp. regulation centers Pulmonary Stretch Receptors - Located in lungs - throughout airways & alveoli Impulses influence normal breathing pattern to protect from excess stretching (overinhalation) When TV reached - stimulus sent to inhibit more inspiration

26 Types of Breathing - Eupnea - normal resp. rate, unaware of breathing
Hypoventilation - slow & shallow Hyperventilation - rapid & deep Dyspnea - labored or difficult Orthopnea - upright position Apnea - breathing stops Cheyne-Stokes Resp. -apnea & hyperventilation Respiratory Arrest - failure to resume breathing after period of apnea


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