6. Respiratory System Flashcards
Describe how air enters the body
Air goes through nares –> filtered through mucous membranes and vibrissae & lysozyme in nasal cavity –> passes into pharynx and larynx –> into trachea –> then into one of two mainstem bronchi —> bronchioles —> alveoli
What and where is the pharynx?
Lies behind nasal cavity at back of mouth. Common pathway for air going to lungs and food going to esophagus
What and where is the larynx?
Lies below pharynx and is only for air to lungs. The epiglottis covers the opening of larynx (glottis) when swallowing. Larynx contains 2 vocal cords maneuvered by skeletal muscle and cartilage
Why do bronchi and trachea have ciliated epithelial cells?
To filter anything that passed vibrissae
What do bronchi further divide to?
Bronchioles and divide further into tiny balloon-like structures called alveoli
Each alveolus is coated with what? Each alveolus is surrounded by what? How is elasticity of alveoli determined?
Surfactant, a detergent that lowers surface tension at air-liquid surface to prevent alveolus from collapsing on itself. Network of capillaries surround each alveolus to carry oxygen and carbon dioxide. Pressure of fluid, not radius of airway (radius = determined by bronchioles)
Visceral vs parietal pleura
Membrane adjacent to lung vs membrane surrounding visceral pleura. Intrapleural space in b/w visceral and parietal pleura
What is the diaphragm?
Thin, muscular structure that divides thoracic cavity and abd cavity; ONLY innervated by phrenic nerve; ONLY consists of skel muscle
Is inhalation an active process? What muscles control inhalation?
Yes it’s an active process. Diaphragm and external intercostal muscles (muscles b/w ribs) expand thoracic cavity –> inc the space in the pleural cavity –> lowering its pressure relative to atmospheric pressure. This forces air down into the lungs and expands the lungs, forming the basis of ‘negative pressure’
What is intrathoracic volume?
The volume of thoracic cavity
Is exhalation an active process? What muscles control exhalation?
No it does not have to be an active process; diaphragm and external intercostal muscles relax. For it to be active, internal intercostal muscles and abd muscles pull rib cage down.
Total lung capacity (TLC) vs residual volume (RV) vs vital capacity (VC) vs tidal volume (TV)? Know what these look like on a graph on pg 333
Max vol of air during complete inhalation, usually 6-7 liters vs vol of air left after exhaling vs difference b/w TLC and RV vs vol of air in/exhaled under nml breath
Expiratory reserve volume (ERV) vs inspiratory reserve volume (IRV)? Know what these look like on a graph on pg 333
Vol of air forcibly exhaled after nml exhalation vs vol of air forcibly inhaled after nml inhalation
How is ventilation/respiration regulated by the brain?
Ventilation/respiratory center = located in medulla oblongata, it’s a collection of neurons; AND PONS - resides in hindbrain, connects cerebrum to hindbrain, responsible for respiration
Central chemoreceptors vs peripheral chemoreceptors vs mechanoreceptors
Central chemoreceptors neighbor around resp center in brain, carry info about CO2 and pH vs peripheral chemoreceptors are outside the brain, carry info about O2, CO2 and pH vs carry info about pressure, sound, touch and motion
What happens when CO2 rises (hypercarbia/hypercapnia/hypoxemia) in blood?
Respiratory rate inc to exhale CO2
Describe where de/oxygenated blood comes from
Deoxygenated blood moves from right heart ventricle to pulmonary arteries to capillaries –> CO2 diffuses from blood to lungs, O2 diffuse from lungs to blood –> Oxygenated blood moves from capillaries to pulmonary veins to left heart atrium
What is thermoregulation? How is it regulated? What does resp system have to do with it?
Regulation of body temp. Heat = regulated by vasodilation or vasoconstriction. If blood vessels expand –> more blood goes through –> larger amounts of thermal energy can be dissipated; if blood vessels constrict –> less blood goes through –> thermal energy conserved. Resp system = highly vascular —> does vasodilation/constriction
What is mucociliary escalator?
When cilia in respiratory tract move pathogens into mucus and to oral cavity to be expelled or swallowed
What is the bicarbonate buffer system?
CO2 + H20 H2CO3 H + HCO3
What happens when body pH is lower than 7.35 (acidemia)?
Acid-sensing chemoreceptors send signals to inc respiratory rate –> more CO2 blown off –> push bicarbonate buffer system to left
What happens when body pH basic (alkemia)?
Dec respiratory –> you need to retain CO2 –> push bicarbonate buffer system to right to reabsorb and produce more H ions and bicarbonate ions
What can’t a spirometer measure?
Residual vol, and consequently TLC
People with IPF have what decreased vol?
TLC, inspiratory vol, and RV
What does passive recoil of lung tissue do?
Dec lung vol —> exhale completely
