Chapter 22 Respiratory System Gross anatomy of respiratory system Serous membrane line internal structures o Visceral and parietal connects adjacent to the rib cage o Each lung has own pleural membrane not connected 11 12 2014 Ribs form fairly sealed chamber 2 critical intercostal muscles o Diaphragm forms bottom of sealed chamber Ventilation movement of air into or out of the pulmonary structures Inhaling through nose Cleaner air and more moisture Nose hairs trap dust particles Inside nasal cavity is pseudo stratified epithelia goblet and columnar cells not usually ciliated o Mucus helps trap dirt and moisten air Nasal meatus grooves that increase the area and cause turbulence more air mixes and comes in contact with mucus membranes allowing us to trap even more dirt Pharyngotympanic tube leads to ears Pharynx connects sinus and mouth to lower structures Mouth lined with stratified squamous Palantine tonsils lingual tonsil uvula not necessary Larynx cartilaginous structure voice box with two muscles Epiglottis elastic cartilage epiglottis closes when you swallow and blocks trachea leading food down esophagus and to the stomach when you breathe epiglottis is open The trachea is a fairly rigid tube due to C shaped rings of hyaline cartilage trachealis muscle functions to contract and relax which alters lumen shape and also Submucosa Mucus membrane pseudostratified epithelia ciliated goblet cells that secrete mucin Bronchiole primarily smooth muscle Conducting zone refers to the structures in the lung that are solely related to ventilation no gas exchange Respiratory zone respiratory bronchiole will divide into alveolar duct and on these are alveoli means sac tiny air sacs where respiration takes place Alveoli made of simple squamous epithelium Oxygen and co2 are lipid soluble simple diffusion Alveolar pores are holes that connect adjacent alveoli which prevents over inflating of some of the alveoli Capillaries are where there is the exchange of nutrients yellow fibers of elastin elastic connective tissue serves to help you exhale without expending energy Surfactant makes water wetter prevents water molecules from interacting with each other Alveolar respiration exchange of gases between alveoli and capillaries Pleural cavity filled with viscous substance that decreases friction Ventilation requires contraction relaxation of the diaphragm to change pressures within the thoracic cavity Sequence of events o Inspiratory muscle contract o Thoracic cavity volume increases o Lungs stretched intrapulmonary volume increases o Intrapulmonary pressure drops o Air gases flows into lungs down its pressure gradient until intrapulmonary pressure is 0 equal to atmospheric pressure Changes in anterior posterior and superior inferior dimension o Ribs elevated and sternum flares as external intercostals contract o Diaphragm moves inferiorly during contraction Changes in lateral dimensions o Ribs elevated and sternum flares as external intercostals contract o Diaphragm moves inferiorly during contraction Expiration o Passive under normal conditions o Inspiratory muscles relax diaphragm rises rib cage descends due to recoil of costal cartilages o Thoracic cavity volume decreases o Elastic lung recoil passively intrapulmonary volume decreases o Intrapulmonary pressure rises o Air gases flows out of lungs down its pressure gradient until intrapulmonary pressure is 0 o Internal intercostals and external obliques ab muscles are related to forced expiration Boyles law o The pressure of a gas varies inversely with its volume P1V1 P2V2 Ventilation simply refers to the movement of air and its contents Respiration involves the exchange of gas molecules that make up the air Daltons law of partial pressure o The total pressure exerted by a mixture of gases is the sum of the pressures exerted independently by each gas o Barometric pressure 760 mm HG multiply by concentration to get partial pressure of each gas o Concentration of gases O2 20 93 CO2 0 003 N2 78 60 H20 0 46 TOTAL 100 How is oxygen transported in the blood o Hemoglobin transports oxygen o 4 proteins have heme core that contain iron and is where oxygen is binded o shape is closed or open o close no oxygen can bind to heme group o high partial pressure of oxygen bombarding hemoglobin heme group catches oxygen molecule o low partial pressure hemoglobin closes o oxygen diffuses across membranes from alveoli to blood down a partial pressure gradient o no meaningful exchange of oxygen in pulmonary veins heart and arteries because exchange of gas only occurs in the capillaries Hemoglobin o Each subunit is from a different gene 4 separate proteins work together and each protein has a heme group with iron in the center o Oxygen binds to iron and as a gas o Hemoglobin within the RBCs o Exists in two states opens when bombarded with oxygen when loses oxygen it closes Oxyhemoglobin dissociation curve Describes the relationship Percent oxygen saturation 100 percent max Hemoglobin has a bonding affinity for oxygen Lungs have high p p of oxygen a lot of oxygen molecules present low partial pressure of oxygen in the tissues o At the tissues much lower p p as the oxygenated blood travels through systemic arteries down to capillaries in the tissues high p p arriving to low p p of oxygen gradient hemoglobins affinity is therefore lower at this point o Hemoglobins affinity for oxygen varies o Medium partial pressure a little oxygen is knocked off hemoglobin low partial pressure more oxygen is knocked off o High partial pressure curve is relatively flat o What happens when barometric pressure is lower partial pressure of oxygen also decreases Percent saturation of hemoglobin o Hemoglobins affinity for oxygen is influenced by temperature o As you increase the temp of blood rightward shift of oxyhemoglobin dissociation curve unload more oxygen o Deliver unload less oxygen at lower temperature o Decrease in blood pH also rightward shift of oxyhemogloblin dissociation curve unload more oxygen Transit time and oxygenation of blood o At rest rBC spends 3 quarters of a second in the capillary o Loading oxygen onto the hemoglobin is not limited in a healthy person Henrys law o When a mixture of gases is in contact with a liquid each gas will dissolve in the liquid in proportion to its partial pressure o Also dependent on solubility of particular gas 02 low solubility in liquid o o o o Co2 high solubility in liquid O2 and CO2 transfer at the tissues o 02 is transported bound to