B. Lining - epithelium

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Simon Marsh
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1 RESPIRATORY SYSTEM Function supply body with oxygen and remove carbon dioxide. This process is called respiration, can be broken down into 4 components. I. Pulmonary Ventilation or breathing movement of air into and out of the lungs II. External Respiration gas exchange between blood and air filled chambers of the lungs III. Transport of Respiratory Gases from lungs, through blood, to cells of the body IV. Internal Respiration gas exchange between blood and cells of body Respiratory System Tour of the Organs (Nose-Pharynx-Larynx-Trachea-Bronchi-Lungs) I. Nose A. Functions filters, moistens, and warms air 3. sense of smell B. Lining 1. epithelium 2. always with 3. movement down to pharynx to be swallowed C. Components 1. Conchae a. superior, middle and inferior bones b. function to surface area for warming, cleaning and humidifying air 2. Paranasal sinuses a. in bones b. maxillary, frontal, sphenoid and ethmoid sinuses c. - lighten weight of skull & provide quality of voice d. lining is continuous with nasal cavity and may lead to Upper Respiratory Infection ( ).. sinusitis 3. Nostrils or Nares 4. Nasal septum ethmoid, vomer and hyline cartilage 5. Hard and soft palate located under the nose (anterior and posterior respectively) 6. Nasal cavity in the nose

2 II. Nasopharynx A. Functions connects nasal cavity to oropharynx B. Lining epithelium C. Components 1. Pharyngeal tonsils ( ) a. composed of tissue b. may become enlarged with URI blocking Eustachian tubes form draining properly 2. Eustachian tubes or -- a. connects to middle ear to equalize air pressure b. URI may lead to infection of middle ear 3. Uvula a. most posterior soft palate that is hanging down b. marks border of nasopharynx and oropharynx c. function is to close during swallowing to prevent food from entering nasal cavity III. Oropharynx A. Functions connects nasopharynx to laryngopharynx B. Lining epithelium (more friction and chemicals) C. Components 1. Lingual and Palatine tonsils a. located on tongue and soft palate respectively b. composed of l tissue c. traps and destroys entering d. may become enlarged with URI 2. Fauces a. opening to IV. Laryngopharynx A. Functions 1. 2., leads to trachea 3., leads to esophagus B. Lining - epithelium

3 V. Larynx A. Functions 1. route food to esophagus and air to trachea 2. tube for 3. B. lining 1. above vocal cords - epithelium 1. below vocal cords - epithelium C. components 1. vocal cords pairs of ligaments that get stretched a. false vocal cords located b. true vocal cords located (voice) 2. glottis opening in 3. epiglottis a. hinged - lid b. covers glottis during swallowing to prevent food from entering lower airways c. larynx moves and when you swallow 4. cartilages a. thyroid Adams apple cartilage b. cricoid below thyroid cartilage c. arytenoids, corniculate, and cuneiform form the lateral and posterior walls VI. Trachea about 4 inches long and 1 inch diameter A. function - B. lining 1. epithelium 2. movement up to pharynx to be swallowed C. components 1. U-shaped hyaline cartilage to prevent walls from 2. smooth muscle a. located posteriorly to increase or decrease b. allows esophagus to expand anteriorly when

4 VII. Bronchi and Bronchial tree A. function transport air to the alveoli ( ) B. lining 1. changes from ciliated pseudostratified columnar to columnar to cuboidal in the terminal bronchioles 2. there is no cilia at the end of the bronchial tree so any debris found there is not swept away, but removed by C. components (branching tubes) 1. primary bronchi, one to each lung 2. secondary bronchi, one to each lobe of lung 3. tertiary bronchi or so, branch smaller and smaller 4. bronchioles a. smallest tubes (less than diameter) b. hyaline cartilage no longer present c. more than found in larger respiratory tubes VIII. Respiratory Zone A. function gas exchange from lungs to blood ( ) B. lining single layer of cells C. components 1. alveoli ducts 2. alveoli sac (grapes) 3. alveoli (grape) a. dead end air sac b. site of gas exchange c. cell types i. type I cells = epithelium -composes most alveoli wall, allows for gas exchange ii. type II cells = epithelium - secrete fluid called surfactant which coats alveoli and reduces surface tension iii. alveolar macrophages -

5 IV. Lungs A. right lung Upper, middle, lower B. left lung Upper, lower C. shape 1. -shaped organs 2. - superior surface 3. inferior surface, sits on diaphragm 4. adjacent to heart 5. next to ribs anteriorly and posteriorly 6. located in pleural cavities D. hilus of lung 1. pulmonary artery (high, low ) 2. pulmonary vein (low, high ) 3. primary bronchi ( ) 4. lymph vessels ( ) 5. autonomic nerves E. pleura 1. consists of serous membrane or 2. contains 2 layers with fluid in between to reduce friction as you inhale and exhale a. connected to outside of lungs b. connected to cavity wall c. continuous at hilus F. physical properties of lungs 1. compliance = a. inhale and lungs enlarge b. disease pulmonary fibrosis which increases collagen fibers and therefore decreases the ability to stretch 2. elasticity = a. exhale and lung get smaller b. partial = normal exhalation c. total = deflated or collapsed lung

6 Pulmonary Ventilation (breathing) I. Pressures A. Boyles gas law 1. pressure of a gas and its volume are related a. if pressure goes, volume goes b. if volume goes, pressure goes c. example helium balloons oxygen tanks 2. air flows from a pressure to a pressure a. if pressure is greater outside the body than inside the body then we b. if pressure is outside the body is less than inside the body then we c. example blowing up a balloon - weather and winds blowing from a high pressure area to a low pressure area B. Atmospheric pressure pushing down on body 1. atmospheric pressure (760 mm Hg at sea level) = barometric pressure (measured in inches) 2. not at sea level? Denver less pressure, C. Intrapleural Pressure = 1. pressure between pleural membranes a. pull on layer lungs trying to recoil surface tension in alveoli b. pull on layer thoracic cavity pulls up and out 2. net intrapleural pressure (756 mm Hg, less than atmospheric pressure) 3. purpose a. to help keep alveoli (what else also helps?) b. to keep the lungs from totally recoiling or 4. what if we didn t have intrapleural pressure? D. Intraalveolar pressure = 1. pressure in 2. at rest = atmospheric pressure (760 mm Hg)

7 II. Process for inspiration process A. Nerve impulse 1. somatic nervous system turns skeletal muscles involved in inspiration a. normal inhalation i. diaphragm nerve ii. external intercostals muscles nerves b. forced inhalation - sternocleidomastoid, scalenes, and serratus anterior B. Muscle contraction causes: 1. diaphragm down and thoracic cavity is a. then volume in thoracic cavity b. this pulls on the lungs c. which intraalveolar volume d. which intraalveolar pressure to below atmospheric pressure e. air rushes lungs 2. summary p. 852 III. Process for expiration process A. Nerve impulse 1. somatic nervous system turns skeletal muscles involved in normal expiration a. normal expiration - diaphragm and external intercostals b. forced expiration - internal intercostals and abdominal muscles to push diaphragm up even more B. Muscle action causes: 1. thoracic cavity walls a. then the volume in thoracic cavity b. lungs c. which intraalveolar volume d. which intraalveolar pressure above atmospheric pressure e. air rushes the lungs 2. summary p. 852

8 Neural Control of Respiration I. Medulla Oblongata sets rhythm for breathing A. Dorsal respiratory group 1. Cluster of neurons in medulla 2. Sets the rate for normal breathing 3. sends action potentials through phrenic and intercostal nerves 4. average respiratory rate breaths/minute 5. inspiration = 2 seconds expiration = 3 seconds B. Ventral Respiratory Group 1. Clusters of neurons in medulla 2. Sets rate for forced breathing by expiration C. Hering-Breuer Reflex 1. Mechanism for inspiration 2. Relies on receptors in lung 3. lung to vagus to medulla II. Pons modifies medulla activity A. Pneumotaxic center 1. clusters of neurons in the superior pons 2. functions to the respiratory rate by limiting inspiration (more breaths/min) B. Apneustic center 1. clusters of neurons in middle pons 2. functions to respiratory rate by prolonging inspiration (less breaths/min) III. Higher brain centers A. Hypothalamus 1. Respiratory rate affected by emotions and pain 2. Examples - children crying - increased body temperature and increased breathing rate B. Motor cortex - control over breathing

9 Chemical Control of Respiration I. Carbon Dioxide and Hydrogen Ions A. These are the major factors in determining respiratory rate 1. if carbon dioxide levels rise, so do hydrogen ion levels 2. they are - related B. Central Chemoreceptors 1. located in medulla oblongota 2. blood brain barrier doesn t allow carbon dioxide to cross but hydrogen ions can cross 3. therefore carbon dioxide levels are measured indirectly C. Peripheral Chemoreceptors 1. located in carotid and aortic bodies 2. transmitted to brain via glossopharyngeal and vagus nerves 3. here carbon dioxide levels are measured directly II. Oxygen A. only extreme variations in oxygen levels cause changes in breathing B. the changes are detected by peripheral chemoreceptors

10 Gas Exchange I. Alveoli microanatomy A. For a gas to get from alveoli to capillary, it must cross layers (plus surfactant) 1. alveoli wall simple squamous epithelium 2. basement membrane (for alveoli and capillary) connective tissue 3. capillary wall simple squamous epithelium II. Factors affecting diffusion rate A. Thickness of alveoli/capillary walls 1. normal thin (.6 micrometers) 2. abnormal thicker B. Surface area of alveoli/capillary walls 1. normal (160 square meters) 2. abnormal less due to C. Diffusion coefficient of gases 1. carbon dioxide is the most gas 2. carbon dioxide diffuses about 20 times easier than oxygen D. Pressure differential across alveoli/capillary wall -gases diffuse from pressure to pressure E. carbon dioxide and oxygen move independently across alveoli/capillary walls III. Dalton Law Total pressure of mixed gases = of partial pressures of individual gases IV. Atmosphere air and pressures = O 2 + CO 2 + N 2 + H 2 0 = 21% +.04% + 79% + (varies) = P O + P CO + P N + P H2O = 160 mmhg +.3 mmhg mmhg + (varies) V. Alveoli air and pressures Alveoli Air = P O + P CO + P N + P H2O P Alveolus = 104 mmhg + 40 mmhg mmhg + 47 mmhg

11 VI. Differences in Atmospheric and alveoli pressures of gases (external respiration measured in mmhg) Atmospheric Alveoli Movement O 2 CO 2 N 2 H 2 O P O drops because O 2 diffuses into blood. P CO increases because CO 2 diffuses into alveoli Used to show totals, we won t discuss N 2 or H 2 O again Therefore concentrations in systemic are P O = 104, P CO = 40 VII. Differences in artery and cell pressures of gases (internal respiration measured in mmhg) Artery Tissue Movement O 2 CO 2 Oxygen moves to cells CO 2 moves to capillaries Concentrations in systemic are P O = 40, P CO = 45

12 Gas Transport I. Hemoglobin A. Review 1. RBC s are 97% hemoglobin (Hb) 2. = iron in the center of this molecule = proteins 3. Each hemoglobin contains 4 proteins with a heme group in the middle B. Hemoglobin Varieties 1. Hemoglobin = a. 4 proteins with an iron containing heme group in the center b. 4 globins on the outside 2. Oxyhemoglobin = a. one oxygen atom has attached to each heme group b. 4 total per molecule 3. Deoxyhemoglobin = a. hemoglobin that has just released oxygen b. hydrogen ions have attached to the globins (proteins) 4. Carbaminohemoglobin = a. carbon dioxide bonds to amino acids of globin b. not heme as oxygen does 5. Carboxyhemoglobin = a. abnormal b. when carbon monoxide is present, it bonds 210 times stronger than HbO 2 and is difficult to detach

13 I. Normal levels A. Arteries = 104 mmhg B. Veins = 40 mmhg O 2 in Blood II. Oxygen Transport in Arterial Blood A. 1% of oxygen is in plasma B. 99% of O 2 carried on in RBC - 97% of all HbO 2 are saturated with O 2 (3% not saturated) III. Loading and unloading of O 2 to cells (picture) Lungs Body cells IV. Variances in unloading = Hb reserve capacity - Hb only releases oxygen needed by cells (no more, no less) A. - 22% of Hb will unload oxygen at cells - 75% will still be loaded B. - 40% of Hb will unload oxygen at cells - 57% will still be loaded C. - 70% of Hb will unload oxygen at cells - 27% will still be loaded

14 I. Normal levels A. Arteries = 40 mmhg B. Veins = 45 mmhg CO 2 in Blood II. Carbon dioxide transport in venous blood A. 7% of CO 2 is in plasma B. 23% of CO 2 is transported by 1. Hb would rather carry oxygen than CO 2 or H + 2. It kicks CO 2 or H + off when it can C. 70% of CO 2 is transported by in plasma 1. HCO 3-2. Equation CO 2 + H 2 O H 2 CO 3 H + + CHO - 3 (Hb that has just given off its O 2 mops up H + ions) In RBC A. CO 2 + H 2 O (carbonic anhydrase) H 2 CO 3 ( ) Then dissociation of acid B. H 2 CO 3 H + + HCO 3 - C. HCO 3 - leaves and enters D. attaches to hemoglobin E. Chloride from plasma enters RBC so membrane doesn t get polarized ( ) F. Reverse happens in lungs

15 Respiratory Diseases/Abnormalities I. Pleurisy A. Inflammation of membranes B. May cause less pleural fluid to be produced and membranes rub C. May cause too much pleural fluid, which hinders pressures and normal breathing II. Infant respiratory distress syndrome = A. Surfactant is produced during the last 2 months of fetal development B. Premature babies that lack surfactant are unable to keep their alveoli inflated between breaths C. Treatment - artificial surfactant and respirators that force alveoli open D. Most babies will eventually produce surfactant and can be taken off respirators III. Hypoxia A. Inadequate oxygen delivery to (blue skin) B. Types 1. Hypoxia poor O 2 delivery from decrease in RBC or from RBC that are lacking Hb 2. Hypoxia blockage of blood flow from heart failure or emboli in blood vessels 3. Hypoxia adequate supply of blood, but cells can t use blood, usually caused by poisoning 4. Hypoxia reduced P O2 caused by pulmonary disease IV. Hyperventilation A. Increase in depth and rate of breathing B. Cause a decrease in C. If CO 2 levels get too low, blood to brain is decreases and person gets faint or passes out. D. Breathing into a paper bag increases CO 2 because you re breathing in expired air V. Apnea A. of breathing B. Sleep apnea pauses in breathing during sleep

16 VI. Chronic Obstructive Pulmonary disease (COPD) A. Emphysema 1. Inspiration a. emphysema destroys b. this increases dead space within the lungs (air not associated with alveoli walls) c. Person needs to inhale deeper to receive normal gas exchange. 2. Expiration a. emphysema causes lungs to lose their ability to b. exhaling should be passive but now forced exhalation is required constantly 3. Bottom line - makes inhaling and exhaling difficult B. Bronchitis excess mucus and inflamed airways make it difficult to breath VII. Asthma A. Caused by inflammation and constriction of B. Triggered by cold air, pollen, other allergens or exercise VIII. Tuberculosis (TB) A. Caused by and spread airborne B. Nodules or tubercles form in lungs that are full of bacteria and decrease lung volumes C. If tubercles break they cause fever, cough, and blood in lungs IX. Lung Cancer A. 90% of lung cancers caused from B. Accounts for 1/3 of all cancers C. Smoking causes cilia and mucus to become nonfunctional D. Then carcinogens from tobacco change normal cells to cancerous cells X. Cystic Fibrosis (CF) A. Genetic disease B. CF causes of mucus that clogs respiratory passages C. This extra mucus is a breeding ground for airborne bacteria D. Death caused from respiratory infection

(Slide 1) Lecture Notes: Respiratory System

(Slide 1) Lecture Notes: Respiratory System I. (Slide 2) The Respiratory Tract A) Major structures and regions of the respiratory Tract/Route INTO body 1) nose 2) nasal cavity 3) pharynx 4) glottis 5)