Respiratory system - Lectures 17-18 Flashcards
4 functions of respiratory system
- gas exchange
- pH regulation (by means of CO2)
- removal of pathogens
- sound
respiratory system bulk flow
- flow takes place from regions of _______ to _______ pressure
- a ________ pump creates pressure gradients
- resistance to air flow is influenced primarily by the ________ of tubes through which air is flowing
- higher to lower pressure
- muscular pump
- diameter
Resistance of air flow
- 90% due to what bc what
- 10% due to what bc what
- 90% due to trachea and bronche –> has cartilage: cannot change size of diameter/change resistance
- 10% bronchioles –> can have dilation and constriction to modify resistance
what is the conducting zone vs respiratory zone?
CONDUCTING ZONE: air just passing through
- nose –> pharynx –> larynx –> trachea –> bronche –> bronchiole
RESPIRATORY ZONE: gas exchanges (mostly in alveoli)
- respiratory bronchioles –> alveoli duct –> alveoli
** bronchiole leads to respiratory bronchiole
what is external respiration vs internal respiration?
EXTERNAL: exchange of air between atmosphere and lungs (+ btw lungs and blood?)
INTERNAL: exchange of gases between blood and cells
4 steps of external respiration ish
- exchange 1: atmosphere to lung (= ventilation)
- exchange 2: lung to blood
- transport of gases in blood
- exchange 3: blood to cells (internal respiration)
CONDUCTING SYSTEM
- upper respiratory tract (4)
- lower respiratory tract (4)
WHAT IS THE SITE OF GAS EXCHANGE?
- UPPER: mouth, nasal cavity, pharynx, larynx
- LOWER: trachea, 2 primary bronchi, their branches, lungs
ALVEOLI! (singular alveolus)
THORACIC CAGE:
- includes what (4 + 1 has 4 subtypes)
- bones and muscles of thorax that surround the lungs
- spine
- rib cage
- muscles: diaphragm, intercostal muscles, sternocleidomastoids, scalenes
- pleural sacs each surround a lung
4 types of muscles in thoracic cage + functions
DIAPHRAGM:
- btw lung cavity and digestive cavity
- contraction = decrease rib cage size
INTERCOSTAL MUSCLES:
- btw ribs
- internal –> contraction = decrease thoracic cage size
- external –> contraction = increase thoracic cage size
- 2 dif layer muscle in different directions
STERNOCLEIDOMASTOIDS:
- neck muscle, linked to sternum
- moves head + lifts rib cage = increase size
SCALENES:
- neck muscle
- linked to 1st and 2nd rib & collar bone
- lifts rib cage up = increase size rib cage
lungs are wrapped by 2 layers of ____A_____ (what type of tissue?) = the ______ _____
- what is contained in the layer of _____A______ –> 2 functions
- what happens if ____A_____ is pierced?
- pleura = connective tissue –> pleural sac forms a double membrane surrounding the lung, similar to a fluid-filled balloon surrounding an air-filled balloon (lung)
- pleural fluid
1. lowers friction between membranes
2. holds lungs tight against thoracic wall –> the pleural fluid prevents pleura from coming apart = hold lung tissue and thoracic wall together as unit - if pleura is pierced –> rib towards outside and lungs collapses bc not held together as a unit anymore = pneumothorax bc air in thorax
Right vs Left lung size and shape
R: shorter and wider
L: longer + has cardiac notch to accommodate apex of heart
which muscles are involved in inhale vs exhale vs forced respiration?
NORMAL INHALE:
- diaphragm contract (flattens) + external intercostal muscle contract = thoracic volume increases
FORCED INHALE:
- diaphragm + external intercostal muscle + 2 neck muscles (sternoclidomastoid + scalenes) = increase thoracic volume
NORMAL EXHALE:
- diaphragm + external intercostal muscle RELAX = thoracic volume decreases (diaphragm is bombé vers le haut)
FORCED EXHALE:
- internal intercostal muscle + abdominal contract to decrease rib cage size
R ventricle –> lung –> pulmonary vein
- long or short distance?
- high or low blood pressure?
short + low blood pressure
each alveoli has 3 types of cells
- describe
+ 2 types of connective tissue
- Type 1 alveolar cell –> gas exchange
- type 2 alveolar cell (surfactant cell) –> synthesizes and secretes surfactant to decrease surface tension
- alveolar macrophage –> ingests foreign material
+ collagen and elastin
primary bronchi ________ out a lot = increase what?
- total cross-sectional area of alveoli/exchange surface
- branches out a lot! = increase surface area
- 75 m^2
- what contains your vocal cords?
- what is your windpipe?
- larynx
- trachea
what do your airways do to the inspired air? (3)
- warming air to body temp
- adding water vapor and muscu to air
- filtering out foreign material
why do we have runny noses during the winter?
because cold air stimulates gland secretion = mucus
- cilia (move extra fluid from nose to mouth to swallow in oesophagus) don’t work well in cold air so mucus/extra fluid comes out from nose
which cells produce mucus?
- what moves mucus toward pharynx? what does the mucus also remove?
- goblet cells
- cilia! mucus removes trapped pathogens and particulate matter
how is saline secreted by airway epithelial cells? (4 steps)
- Na+/K+/2Cl= symporter (NKCC) brings Cl- into epithelial cell from ECF
- apical anion channel including CFTR (Cystic fibrosis transmembrane regulator channel) allow Cl- to enter lumen of airway
- Na+ goes from ECF to lumen by paracellular pathway, drawn by electrochemical gradient (drawn to negative charge of Cl- in lumen)
- NaCL movement from ECF to lumen creates a concentration gradient so water follow to lumen
*Cystic fibrosis: NO CFTR –> no Cl-, Na+ or water in lumen —> mucus blocked in trachea/airways
describe Boyle’s law and Dalton’s law
BOYLE’S LAW:
- P1V1 = P2V2
- pressure volume inverse relationship
DALTON’S LAW:
- total pressure equals sum of all partial pressures
- Pt = pp1 + pp2 + pp3
in humid air, water vapor ______ the contribution of other gases to the total pressure
- what is the normal atmospheric pressure?
- how to calculate partial pressure of a gas in humid air?
- DILUTES!
- 760 mm Hg
- at 25°C, 100% humidity: 155 mmHg O2 (21% of air) + 0.24 mm Hg CO2 (0.03% of air) + 24 mmHg water (100% humidity)
- Pgas in humid air = (Patm - PH2O) * % of gas
ie: PO2 = (760-24) * 0.21 = 155 mmHg
what is
- TIDAL VOLUME (VT)
- INSPIRATION RESERVE VOLUME (IRV)
- EXPIRATION RESERVE VOLUME (ERV)
- RESIDUAL VOLUME (RV)
- VT: volume that moves during a respiratory cycle (air that gets in/out during normal breathing) (kinda like stroke volume)
- IRV: additional volume above tidal volume (when you use neck muscles)
- ERV: forcefully exhaled after end of normal expiration (when you use abs and internal intercostal muscles)
- RV: volume of air in respiratory system after maximal exhalation
what machine can do pulmonary function tests?
spirometer!
can measure difference in volume during inspiration and expiration
IRV, VT, ERV and RV for males vs females
- total lung capacity?
MALES:
- IRV = 3000 mL
- VT = 500 mL
- ERV = 1100 mL
- RV = 1200 mL
- total = sum = 5800 mL
FEMALES:
- IRV = 1900 mL
- VT = 500 mL
- ERV = 700 mL
- RV = 1100 mL
- TOTAL = 4200 mL
air flow is proportional to what?
- inspiration occurs when what decreases/increases?
- vs when does expiration occur?
- flow proportional to deltaP / resistance (just like blood flow)
- inspiration –> alveolar pressure decreases
- expiration –> alveolar pressure increases
__________ pressure inside the pleural cavity keeps the lungs inflated –> how much?
- in normal lung at rest, ______ _____ keeps lung adhered to chest wall –> what happens to pressure when we inhale?
- subatmospheric pressure –> -3 mm Hg
- pleural fluid keeps lung to chest
- inhale = lungs get bigger = pressure decreases (-3 to -6 mmg Hg) –> air gets in through pressure difference