respiratory (23)

purpose of the respiratory system

to supply O2 to the blood & get rid of CO2 from blood

respiratory system consists of:

nose & nasal cavity, throat (pharynx), voice box (larynx), windpipe (trachea), bronchial tubes, lungs

respiratory system functions

ventilation, cleaning & filtering air, gas exchange, gas transport, smell, speech

nostrils

(external nares) outer opening into the nasal cavity

location of nasal conchae

on the lateral walls of the nose

internal nares

located in the back opening of nasal cavity into pharynx

function of olfactory epithelium

detection of smell

function of pseudostratified ciliated columnar epithelium & goblet cells lining the nasal cavity

1) large blood supply warms air mucous 2) moistens air & traps dust 3) cilia move mucous towards pharynx

function of paranasal sinuses that open into nasal cavity

lighten the skull & resonate the voice

paranasal sinuses

a group of 4 paired air-filled spaces that look like a sponge & are located in ethmoid, sphenoid, frontal & maxillary bones

pharynx

5" long muscular tube, extends from internal nares to larynx

functions of pharynx

passageway for food & air, resonating chamber for speech production, tonsils protect from infection

3 distinct regions of pharynx

nasopharynx, oropharynx, laryngopharynx

location of nasopharynx

superior portion of pharynx, extends from internal nares to end of soft palate & is the opening of auditory (Eustachian) tubes from middle ear

lies in the roof of the nasopharynx

adenoid & pharyngeal tonsil

cells that line nasopharynx & trachea

pseudostratified ciliated columnar epithelium with goblet cells

function of nasopharynx

passageway for air only

location of oropharynx

sits behind the oral cavity & extends from end of soft palate to tip of epiglottis

oropharynx consists of

palatine tonsils found on side walls & lingual tonsils under the base of the tongue

cells that line oropharynx & laryngopharynx

stratified squamous epithelium

oropharynx & laryngopharynx

common passageways for food & air

location of laryngopharynx

extends from tip of epiglottis to end of cricoid cartilage, has a side entrance into larynx & end of esophagus inferiorly

larynx consists of _

9 cartilages & connective tissue: 3 single cartilages, 3 paired cartilages + vocal cords (voicebox)

3 single cartilages of larynx

thyroid, cricoid, epiglottis

3 paired cartilages of the larynx

arytenoid, corniculate, cuneiform

location of trachea

5" long & 1" in diameter that extends from larynx into chest where it divides to form the 2 main bronchi

which part of the respiratory system has 16-20 incomplete C-shaped cartilage rings

trachea

anatomy of the lungs

base & apex in both, cardiac notch in left only, right has 3 lobes + oblique & horizontal fissures, left has 2 + oblique fissure

which lung contains an oblique & horizontal fissure, resulting in 3 lobes

right lung

which lung contains a cardiac notch & an oblique fissure only, producing 2 lobes

left lung

_ & enter lungs at the hilum

blood vessels & bronchi

form the roots of the lungs

hilum

lungs are covered with ___

visceral pleura membrane

smaller compartments within lobes of the lungs

lung lobules

composition of lung lobules

terminal bronchiole dividing into respiratory bronchiole which are connected to individual alveoli & multiple alveoli along alveolar duct which end at alveolar sacs

functions of terminal bronchioles

supply air to lung lobules

lung lobules are covered in ___ which are very important in gas exchange

alveolar capillaries

function of alveolar ducts

supply air to alveolar sacs

pneumocytes

alveolar cells

type I pneumocytes function

make the alveolar epithelium wall

type II (septal) pneumocytes function

secrete surfactant (oily secretion containing phospholipids & proteins that break up the surface tension to make it easier to breath

type III pneumocytes

alveolar macrophage cells

composition of respiratory membrane

6 layers: 4 tissue layers & 2 fluid layers

function of respiratory membrane

separate lung capillary blood from alveolar air to allow O2 diffusion from alveolar air into lung capillary & allow CO2 diffusion from lung capillary into alveolar air

the respiratory membrane allows _ diffusion from alveolar air into lung capillary

oxygen

the respiratory membrane allows _ diffusion from lung capillary into alveolar air

carbon dioxide

pulmonary ventilation (negative draft ventilation)

physical movement of air into and out of the respiratory tract

breathing in

inspiration or inhalation

breathing out

expiration or exhalation

alveolar pressure

pressure within the lung

intrapleural pressure

pressure within the pleural cavities (always less than atmospheric pressure) that keeps lungs attached to chest wall & inflated

Boyle's Law

as the size of a closed container decreases, pressure inside the container is increased, as the size of the container increases pressure inside the container decreases

pulmonary ventilation modes of breathing

quiet breathing (eupnea), and forced breathing (hyperpnea)

quiet resting ventilation - eupnea

air moves into lungs when alveolar pressure inside the lungs is less than atmospheric pressure, air moves out of lungs when atmospheric pressure is less than alveolar pressure inside the lungs

describe resting inspiration or inhalation (quiet resting ventilation)

contraction of diaphragm & external intercostal muscles enlarges the chest & reduces alveolar pressure to less than atmospheric pressure, air drafts into lungs (negative draft) and resting inspiration or inhalation occurs

describe resting expiration or inhalation (quiet resting ventilation)

diaphragm & external intercostals muscles relax, chest gets smaller, elastic recoil of alveoli creates alveolar pressure greater than atmospheric pressure and air is pushed or squeezed out of lungs

forced inspiration

requires larger decreases in alveolar pressure

forced expiration

requires larger increases in alveolar pressure

muscles that support forced inspiration

diaphragm, external intercostal muscles, back muscles

diaphragm & external intercostal muscles

contract more forcefully to make the chest wider during forced inspiration

back muscles

contract & pull the rib cage backwards making the chest wider during forced inspiration

diaphragm, external intercostal muscles, back muscles work together creating a bigger decrease in alveolar pressure during forced inspiration to result in

deeper breaths

muscles that help with forced expiration

diaphragm, external intercostal muscles, internal intercostal muscles, abdominal muscles

which muscles relax during forced expiration?

diaphragm & external intercostal muscles

which muscles contract during forced expiration?

internal intercostal muscles, abdominal muscles

steps of forced expiration

diaphragm & external intercostal muscles relax, internal intercostal muscles contract compressing rib cage & making chest narrower, abdominal muscles contract compressing abdomen & forcing diaphragm to move up further, forcing air out

lung volume

one measure of a quantity of air

capacity

sum of two or more volumes

spirometer

a device for measuring volumes & capacities

spirogram

the record of lung volume & capcity

ventilation rate

number of breaths per minute

adult resting ventilation rate range

12-18 breaths / minute

tidal volume (Vt)

amount of air in one breath at rest

at rest, tidal volume equals

500 mL

how much air reaches the alveoli at rest & is the only air that participates in gas exchange

350 mL

of resting tidal volume remains in airways above alveoli & does not participate in gas exchange

150 mL

anatomic dead air

the remainder of air (150 mL) in the airways above alveoli that does not participate in gas exchange

name the lung volumes

tidal volume (Vt), inspiratory reserve volume (IRV), expiratory reserve volume (ERV), residual volume (RV)

inspiratory volume

volume of air inspired in addition to Vt (yawning volume)

expiratory volume

volume of air expired in addition to Vt (sneeze, cough)

residual volume

volume of air that cannot be expired even with maximum forced expiration

name the lung capacities

inspiratory capacity (IC), functional residual capacity (FRC), vital capacity (VC), total lung capacity (TLC)

inspiratory capacity (IC)

Vt + IRV (amount of air you can take in)

functional residual capacity (FRC)

ERV + RV (how much air we can push out + residual volume)

vial capacity (VC)

Vt + IRV + ERV (usable capacity of lung)

total lung capacity (TLC)

Vt + IRV + ERV + RV

FEV1

stands for Forced Expiratory Volume in 1 second (type taken in the hospital)

FEV1 represents the % of vital capacity that is

forcedly expired in one second

FEV1 should be _ or higher in healthy adults

75%

if FEV1 is lower than 75%, that indicates ___

airways obstruction, lung diseases or weakness of respiratory muscles

external respiration

in the lungs, diffusion of O2 from alveolar air into blood, diffusion of CO2 from blood into alveolar air

internal respiration

in tissues, diffusion of O2 from blood into tissues, diffusion of CO2 from tissues into blood

internal respiration occurs in

tissues

external respiration occurs in

lungs

gas exchange

diffusion across the extremely thin respiratory membrane or capillary wall from higher concentration to lower concentration of gases

Dalton's Law of Partial Pressure (Pg)

in a mixture of gasses, the total pressure is equal to the sum of pressures contributed by each individual gas (partial pressures)

partial pressures (Pg)

our atmosphere air is a mixture of N, O2, CO2 & H2O + trace gases

total atmospheric pressure

essentially equal to the sum of our air's partial pressures

PN2 + PO2 + PCO2 + PH20 = 760 mmHG

PaCO2 (40 mmHg)

symbol for partial pressure of carbon dioxide in oxygenated (arterial) blood