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what is respiration
supply body with O2 for cellular respiration; dispose Co2 as waste product
what is pulmonary ventilation?
movement of air into and out of lungs; movement of outside air to where gas can be absorbed
what is external respiration
- air corss membrane in the alveoli; becomes internal
- exchange of O2 and CO2 between lungs and blood
what are the two components of respiratory system?
respiratory system and circulatory system
what are the components of circulatory system?
- transport of O2 and CO2 in blood
- internal respiration: O2 and CO2 exchange between systemic blood and vessels and tissues
besides exchanging gases what are other functions of the respiratory system?
olfaction and speech
what are the two components of the respiratory system?
- conduction zone
- respiratory zone
where and what is the conducting 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
what is the respiratory zone?
- site of gas exchange
- microscopic structures: respiratory bronchioles, alveolar ducts and alveoli
describe the respiratory mucosa?
- 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
what is pharynx
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
what are the function of sinuses?
- open cavities in the skeletal structures
- lightens the skill
- helps secrete mucuous (overproduction leads to intense pressure)
what is the role of auditory tubes?
equilibriate pressure from ear to pharynx
what is the uvula
- hangs at the end of the soft palate
- when you swallow, pharynx goes bak with uvula prevents food from going into nasal cavity
where does the air enter through the larynx
through the glottis
what is the larynx composed of?
- epiglottis projects over th glottis during swallowing
- made of nine cartilages, ligaments and skeletal muscle
- thyroid and cricoid cartilage
where does the thyroid cartilage form?
anterior and lateral surfaces of larynx
where does the cricoid cartilage form?
ring of cartilage just inferior to thyroid cartilage
which ligament of the larynx is elastic?
epiglottis, all the other are stiff and hyline
what happens to the larynx during puberty?
entire larynx enlarges as result of increase in testerone
why cannot you swallow and say something at the same time?
when you swallow the epiglottis is closed off, to make a sound: you need air through the hole
where are the vocal ligaments?
- elastic fibers enclosed in epithelium deep to laryngeal mucosa
- attach artenoid cartilages to thyroid cartilage
how do you produce a low note?
long and thick vocal cords
why is your voice a specfic note?
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
when you are sick, why is your voice lower?
build up of mucus; swelling; get thicker vocal cords
to do you get a louder voice?
what is the trachea?
- 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
what are the three layers of tracheal wall?
- 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
what is the trachealis
- 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)
describe the branching of the bronchi tree
- 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
what are the differences between the tubes in trachea and bronchioles
- 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
each terminal bronchiole supplies one lobule or bronchopulmonary segment
stem to grapes, pulmonary arteriole and pulmonary vein wrapped around
what does the respiratory zone consist of?
respiratory bronchioles (terminal bronchioles) to alveolar ducts to alveolar sacs
what are 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
what are two types of alveoli
- 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
what are alveolar pores for?
connect adjacent alveoli and equalize air pressure through lung
what happens to the dead alveolar macrophages?
carried by cilia to throat to swallow
what is the respiratory membrane?
where simple diffusion of gases occur
what are the three layers of the respiratory membrane
- squamous epithelial cells lining the alveoli
- endothelial cells of adjacent capillary
- fused membranes between alveolar and endothelial cells
what are pleural cavities?
surround each lung within the thoracic cavity
what are the two types of pleural cavities?
- 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)
what is intrapulmonary pressure?
pressure in the alveoli, fluctuates with breathing; equalizes with Pressure of the atmosphere
what is intrapleural pressure?
- pressure in the pleural cavity
- -fluctuates with breathing, always a negative pressure
what is the negative pressure of the intrapleural pressure caused by?
- 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
what is transpulmonary pressure?
- pulmonary pressure - intrapleural pressure
- this is the pressure that keeps the ariways open
- greater transpulmonary pressure larger lungs
when does lung collapse occur?
when the pulmonary pressure equals the intrapleural pressure or the atmospheric pressure
what is boyle's law?
pressure varies inversely with volume
what happens in the contraction of the diaphragm?
pulls it downward, expanding the lungs
what happens when you contract the interocstal muscles
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
what is forced inspiration
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
what happens to the intrapleural pressure during inspiration and expiration?
- pleural cavity pressure becomes more negative as chest wall expands during inspiration
- returns to initial value as chest wall recoils
what pressures are equal at the end of inhalation and end of exhalation?
intrapulmonary pressure and atmospheric pressure are equal
what are the physical factors that influence pulmonary ventilation?
- 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
where does the highest resistance occur? lowest?
medium sized bronchi in the conducting zone; smallest resistance is in the terminal bronchioles b/c of so many branching
what is vital capacity?
- 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
why do you have residul volume left?
so your lungs won't collapse; if the lungs were empty, aveoli with water molecules would not be able to inflate