Lesson 17: Respiratory System

asthma

-can combat it by inhaling corticosteroids mixed with a bronchodilator which dilates the airways -can also combat it by using an epipen (epinephrine causes sympathetic response=bronchodilation)

one alveolus

-alveoli have their own membrane -each alveolus is surrounded by a capillary (red jelly bean lookin' things that have a red blood cell in them) 1) oxygen comes into alveolus through alveolar pore 2) THREE IMPORTANT CELLS IN ALVEOLUS: Alveolar Type I : simple squamous (so it's thin enough for oxygen and CO2 to diffuse across it), diffusion and filtration Alveolar Type II : secretes surfactant, prevent alveoli from collapsing (prevents balloon from sticking to itself, oil in balloon analogy) Alveolar Macrophage (dust cells) : "big eaters" = garbage men of body, eliminate debris and things we don't want; break down dust we breathe in (that didn't already get stuck in mucous)

bronchioles and alveoli

-lattice of smooth muscle and elastic fibers=control bronchodilation and bronchoconstriction -alveoli=gas exchange occurs cons of smooth muscle in bronchioles: -toon much vasoconstriction can lead to suffocation from lack of oxygen -such as asthma or an allergic reaction that causes vasoconstriction (wheezing, coughing, shortness of breath = airways aren't open enough)

#3 Larynx On its journey deep into the lungs, air passes through the nasal cavity, pharynx, larynx, trachea, and bronchial tree. List the important structural features and functions of each of these organs.

-voice box -production of speech -open airway for us EPIGLOTTIS -made of elastic cartilage -very flexible -very important in directing air and food -drops down and covers larynx (so food doesn't go down respiratory tract) when we swallow food -routes food down esophagus -opens when we breath -works together when hyoid (epiglottis drops when hyoid moves) VESTIBULAR FOLDS -false vocal cords VOCAL FOLDS -true vocal cords Types of Cartilage in Larynx: (see image)

#5 Bronchial Tree On its journey deep into the lungs, air passes through the nasal cavity, pharynx, larynx, trachea, and bronchial tree. List the important structural features and functions of each of these organs.

-looks like an upside down tree with trachea trunk -all the types of bronchi have cartilage in them -bronchioles do NOT contain cartilage -first branch coming off the trachea is the primary bronchi -secondary bronchi branch off from there (2 on the left, 3 on the right) -tertiary bronchi from there (8-10 on the left, 10 on the right) -smaller bronchi -a lot more bronchiole divisions once it gets to bronchioles -microscopic, can no longer see them with naked eye -no longer contain cartilage (cartilage keeps airways open, does not allow constriction or dilation; airway can never collapse, but it also doesn't allow for regulation of the amount of air going into the lungs; if we exercise we want bronchodilation, if not, we want bronchoconstriction) -made of smooth muscle -b/c it's made of smooth muscle, bronchoconstriction and bronchodilation are possible (smooth muscle contracts or relaxes) changing the amount of air that is able to pass through the bronchioles -sympathetic nervous system controls bronchodilation

Differentiate between the upper and lower respiratory tract.

-organ systems are made of multiple organs -respiratory system=all of the organs associated with breathing/respiration -respiratory tract: the part of the respiratory system that air passes through (transportation involved) -upper respiratory tract (superior): sphenoidal sinus, frontal sinus, nasal cavity, pharynx -lower respiratory tract (inferior): larynx, trachea, bronchi, lungs -everything below the pharynx is lower respiratory tract -diaphragm: NOT directly involved with air passing through it, though it IS important in breathing; THEREFORE, it is NOT PART OF the respiratory tract Superior to inferior mneumonic: Potato/Pharynx Lettuce/Larynx Tomato/Trachea

bronchioles and alveoli again

-respiratory bronchiole is what actually goes down into the alveolar sacs -air passes through the alveolar duct, leading to the alveoli themselves -for oxygen to get into the bloodstream, it must travel BOTH across the alveolar membrane AND through the capillaries into the bloodstream

#1 Nasal Cavity On its journey deep into the lungs, air passes through the nasal cavity, pharynx, larynx, trachea, and bronchial tree. List the important structural features and functions of each of these organs.

Functions -airway for respiration -psuedostratified ciliated columnar epithelium (protection=pseudostratified, ciliated=allows movement across epithelium/moves mucous for example to stomach, goblet cells=produce mucous that capture pollutants and protect lungs from them) -warm, humidify, and clean inhaled air (cleans air via mucous, pseudostratified ciliated columnar has mucous, goblet cells produce mucous; air spirals as it hits nasal concha, causing air to come in contact with warm mucous membrane=thus lungs receive warmed and humidified air) -resonating chamber for speech and sound (different sizes of guitars=different size resonating chambers=different sound; similarly each of us has a different size/shape nasal cavity=huge part of why we sound the way that we do when we talk) -houses olfactory receptors (cribriform plate comes down, olfactory neurons from olfactory nerve come down and pick up things in the nasal cavity)

List and explain the major functions of the respiratory system.

Functions: -pulmonary ventilation=breathing -gas exchange, major function of respiratory system (gases such as CO2 and oxygen travel across the membrane and enter the bloodstream; external respiration takes place within the lung alveoli in the blood vessels; oxygen passes through the lung alveoli and across the blood vessels where it enters the bloodstream) -gas conditions=warms, humidifies, and cleanses the air that we breathe in (outside in the cold=warms the air, pollutants stick to mucous/boogers are good=cleansed) -sound production (larynx=voice box) -olfaction (smell, nasal cavity, olfactory nerve, cribriform plate, nose) -defense

What changes the volume within the lungs? controlled by different muscles

INSPIRATION air is going in force is driven by lower pressure inside the lungs low pressure system is created by increasing the volume volume of lungs is increased thanks to the diaphragm when the diaphragm contracts, it pushes down making more space, increasing volume external intercostals contract, expanding ribcage, increasing volume scalenes contract

Explain the relative roles of the various respiratory muscles and lung elasticity in producing the volume changes that cause air to flow into the lungs (during inspiration) and out of the lungs (during expiration).

What happens to the pressure of a system as volume increases within that system? pressure decreases as volume increases

Describe the structure and function of lung alveoli, including a description and a close-up, labeled diagram of alveolar cells and the respiratory membrane.

breathe in > air passes through nasal cavity > air passes through three parts of pharynx > goes down larynx > goes down trachea > goes down bronchiole tree > becomes bronchioles (microscopic and no cartilage) > alveolar sacs (where gas exchange occurs) each individual marble -ish thing is one alveolus alveoli increase the amount of surface area so that we can absorb more oxygen where oxygen and CO2 are transported across membranes

Laryngoscope

can send a tube down throat and larynx to look at it can see vocal folds, vestibular folds, epiglottis

Describe the gross anatomy of the lungs and pleurae.

gross anatomy = can see with the naked eye hilum = where the bronchi and veins and arteries all go into the lung apex = point of the lung superior lobe inferior lobe middle lobe = exists only on right lung right lung has 3 lobes, left lung has 2

how diffusion occurs

layers oxygen crosses: -alveolus -simple squamous cell for oxygen to diffuse across (type I alveolar cell) -capillary (also a simple squamous cell that is crossed) -enters the bloodstream -oxygen binds to red blood cell breathe out=CO2 diffuses across membrane breathe in=oxygen goes into bloodstream

#2 Pharynx On its journey deep into the lungs, air passes through the nasal cavity, pharynx, larynx, trachea, and bronchial tree. List the important structural features and functions of each of these organs.

nasal cavity > pharynx/throat > trachea pharynx=connection between larynx and nasal cavity, also connected to the mouth (connects the nasal cavity and mouth to larynx and esophagus) esophagus=yellow arrowhead larynx=blue arrowhead Three regions of pharynx 1. nasopharynx (superior): connects to the nasal cavity 2. oropharynx: connects to the oral cavity 3. laryngopharynx (inferior): connects to the larynx blue arrow = air nasal cavity > nasopharynx > oropharynx > laryngopharynx > larynx oral cavity > oropharynx > larynx yellow arrow = food oral cavity > oropharynx >laryngopharynx > esophagus NASAL CAVITY: pseudostratified ciliated columnar epithelium NASOPHARYNX: pseudostratified ciliated columnar epithelium OROPHARYNX: stratified squamous epithelium (more protective for food contact) LARYNGOPHARYNX: stratified squamous epithelium (more protective for food contact)

#4 Trachea On its journey deep into the lungs, air passes through the nasal cavity, pharynx, larynx, trachea, and bronchial tree. List the important structural features and functions of each of these organs.

pharynx larynx trachea flow of air: nasal cavity > nasopharynx > oropharynx > laryngopharynx > larynx > trachea carina: point of spit in the trachea, important in the cough reflex, causes things to go back up to where it can be swallowed (if it wasn't air that came down) -esophagus is directly next to (posterior to) trachea -the wall of it is muscular, not rigid (not cartilage) -trachea is made of c-shaped cartilage (not a full ring) -b/c of this, the esophagus is able to expand into the c of the trachea when we swallow large things, giving it more space -if it expands so much that it pushes on the cartilage, it can be painful trachea is lined with pseudostratified ciliated columnar epithelium (as is most of the respiratory tract besides the oropharynx and laryngopharynx which are stratified squamous) goblet cells (within pseudostratified columnar epithelium)=produce/secrete mucous (imagine a goblin with a big goblet full of mucous) breathe in pollutants stick to mucous produced by goblet cells cilia move mucous up respiratory tract, up larynx, and then we swallow it down (function of cilia are to remove that mucous) pollutants destroyed in stomach acid

Briefly explain how the respiratory system develops during the embryonic period.

pleural fluid=between the two membranes of the pleurae, made to reduce friction parietal pleura (superficial) pleural cavity with pleural fluid (in between) visceral pleura (touching organ, most deep) remember the pleura is a type of serous membrane

molecules flow from high pressure systems to low pressure systems

pressure gradients and chemical gradients

hilum includes

primary bronchi, pulmonary veins, pulmonary arteries

Define external respiration and internal respiration.

the difference is the location of gas exchange external: gas exchange takes place from the air into our blood, takes place at alveoli, O2 is diffusing from the air into the blood, CO2 is diffusing from the blood into the air internal: gas exchange between the blood and tissue cells, occurs in systemic capillaries , O2 diffuses from the blood into the body cells to be used, CO2 diffuses from the body cells into the blood