physio nov 15

supply body with O2 for cellular respiration; dispose Co2 as waste product

movement of air into and out of lungs; movement of outside air to where gas can be absorbed

• air corss membrane in the alveoli; becomes internal
• exchange of O2 and CO2 between lungs and blood

respiratory system and circulatory system

• transport of O2 and CO2 in blood
• internal respiration: O2 and CO2 exchange between systemic blood and vessels and tissues

olfaction and speech

• conduction zone 
• respiratory zone

• includes all structure from nasal cavity to larger bronchioles
• cleanses, warms, humidifies air
• lined with respiratory mucosa with cilia
• conduits of gas exchange sites

• site of gas exchange
• microscopic structures: respiratory bronchioles, alveolar ducts and alveoli

• pseudostratified or stratified columnar lined
• ciliated-packed with mucus secreting cells
• muscous traps particles; cilia moves it to pharynx to esophagus to swallow
• cilia in nasal cavity waving things down

a muscular tube shared by respiratory and digestive systems, lined with stratified squamous epithelium (goes from pseudo-one layer- to stratified to protect from super hot liquids)

• swirls air to stimulate olfactors; warm it, humify it, also cools air coming out
• highly vasculated (warms cold air)
• block large particles, gets stuck in the mucosa when particles bump into the wall

• open cavities in the skeletal structures
• lightens the skill
• helps secrete mucuous (overproduction leads to intense pressure)

equilibriate pressure from ear to pharynx

• hangs at the end of the soft palate
• when you swallow, pharynx goes bak with uvula prevents food from going into nasal cavity

through the glottis

• epiglottis projects over th glottis during swallowing
• made of nine cartilages, ligaments and skeletal muscle
• thyroid and cricoid cartilage

anterior and lateral surfaces of larynx

ring of cartilage just inferior to thyroid cartilage

epiglottis, all the other are stiff and hyline

entire larynx enlarges as result of increase in testerone

when you swallow the epiglottis is closed off, to make a sound: you need air through the hole

• elastic fibers enclosed in epithelium deep to laryngeal mucosa
• attach artenoid cartilages to thyroid cartilage

long and thick vocal cords

b/c of the length and the structure of the vocal cords, when you talk, the skeletal muscles in larynx move, which tightens or lengths the vocal cords

build up of mucus; swelling; get thicker vocal cords

more air 

• windpipe-extends from cartilage of the larynx to branches of primary bronchi
• walls supported by C shaped tracheal cartilages
• open part of cartilage face posteriorly towards the esophogus

• mucosa-ciliated pseudostratified epithelium with goblet cells
• submucosa (layer of mucus sheet) connective tissue with seromucous glands
• adventitia: outermost layer made of connective tissue; encases C shaped rings of hyaline cartilage

• muscle connects posterior parts of cartilage rings
• -contracts during coughing to expel mucus (increase pressure, constriction narrows the diameter of trachea: more forceful expel)
• -sympathetic stimulation increases diameter for large volumes of air (relax trachealis, need large amout of air during exercise)

• trachea branches into two primary bronchi (right is steeper)
• secondary bronchi branch off primary, enter the lung lobes (secondary bronchi: each goes to a lobe)
• tertiary bronchi-supply the bronchopulmonary segment
• further branching creates bronchioles (terminal bronchioles)
• entire bronchial tree branches about 23 times

• from C-shaped ring to irregular plates
• from pseudo-stratified to cubidol (smaller distance for gas exchange)
• increase in smoth muscle as we go down; lost cartilage, pick up smooth muscles: bronchioles so we can change the diameter of the respiratory pathway

stem to grapes, pulmonary arteriole and pulmonary vein wrapped around

respiratory bronchioles (terminal bronchioles) to alveolar ducts to alveolar sacs

• chambers connect to multiple individual alveoli (site of gas exchange)
• about 300 million alveoli make up most of lung volume
• surrounded by find elastic fibers and pulmonary capillaries (stretch it and it recoils, but can't constrict or dilate it)
• no skeletal muscle to steal the oxgen and create big distance

• alveolar walls are composed of a single layer of squamous epithelium (type I alveolar cells)
• scattered cuboidal type II alveolar cells secrete surfactant and antimicrobial proteins
• extensive capillary network in alveoli

connect adjacent alveoli and equalize air pressure through lung

carried by cilia to throat to swallow

where simple diffusion of gases occur

• squamous epithelial cells lining the alveoli
• endothelial cells of adjacent capillary
• fused membranes between alveolar and endothelial cells

surround each lung within the thoracic cavity

• visceral pleura: serous membrane covering outer surface of lungs
• parietal pleura: lines inside of chest wall, diaphragm
• pleural layers secrete serous fluid into pleural cavity to reduce friction
• (fluid creates surface tension to keep the layers together)

pressure in the alveoli, fluctuates with breathing; equalizes with Pressure of the atmosphere

• pressure in the pleural cavity
• -fluctuates with breathing, always a negative pressure

• opposing forces
• 2 inward forces promote lung collapse
• -elastic recoil of lungs decrease lung size
• -surface tension of alveolar fluid
• 1 outward force enlarge lungs
• -elasticity of chest wall pulls thorax outward

• pulmonary pressure - intrapleural pressure 
• this is the pressure that keeps the ariways open
• greater transpulmonary pressure larger lungs

when the pulmonary pressure equals the intrapleural pressure or the atmospheric pressure

pressure varies inversely with volume

pulls it downward, expanding the lungs

elevates rib cage, expands thorax

• it is an active process beginning with muscle contraction
• diaphragmn descends, rib cage rises
• thoracic volume increases
• lungs are stretched; intrapulmonary volume increases
• intrapulmonary pressure drops to -1
• air flows in down its concentration gradient until intrapulmoary pressure is o

uses accessory muscles to further increase thoracic cage size

• inspiration muscles relax (diaphragm rises, rib cage descends due to recoil of costal cartilages)
• thoracic cavity volume decreases
• elastic lungs recoil passively, intrapulmonary volume decreases
• intrapulmonary pressure rises to +1. Air flows out of lungs down its pressure gradient

• pleural cavity pressure becomes more negative as chest wall expands during inspiration
• returns to initial value as chest wall recoils

intrapulmonary pressure and atmospheric pressure are equal

• airway resistance: friction is the major nonelastic source of resistance to gas flow (resistance is insignificant since large airways and many branches)
• elasticity of the lungs: (want to recoil once it is pulled out)
• friction (nonelastic): due to turbulent air flow
• lung compliance: how stretchy it is, easier to expand when it is more stretchy (difficult breathing when it is low
• alveolar surface tension: surfactant reduces surface tension/alveoli would collapse without it

medium sized bronchi in the conducting zone; smallest resistance is in the terminal bronchioles b/c of so many branching

• total amount of exchangeable air or the maximum amount of air that can be moved during one respiratory cycle
• vital capacity=tidal volume+inspiratory reserve volume+expiratory reserve volume

so your lungs won't collapse; if the lungs were empty, aveoli with water molecules would not be able to inflate