Respiratory System

Upper Respiratory Tract Components

mouth, nose, pharynx, larynx : conducting zone

Nose

upper respiratory: warms filters moistens inhaled air

olfactory epithelium/nerves detect odors

respiratory epithelium secretes mucus

Pharynx

upper respiratory : 3 regions nasopharynx, oropharynx, laryngopharynx

receives air from mouth/nose

from pharynx air passes glottis (opening of larynx)

Nasopharynx

1) air passage with pharyngeal tonsil

Oropharynx

2) common route for food and air

laryngopharynx

extends to the larynx

Larynx

voice box

glottis (space between vocal cords

Vocal cords/ sound

affect sound by vibrating when air from lungs passes them 

Epiglottis

covers glottis opening of larynx

closes when eating/drinking open when breathing

Lower Respiratory Tract components

trachea, bronchial tree, lungs: gas exchange

Trachea

extends larynx to thoracic cavity

ciliated mucous lining

cshaped rings to hole trachea open 

Bronchial Tree

primary,secondary (lobar: go to diff lobes of lungs), tertiary

Alveoli

gas exchange via diffusion (capillaies surrounding)

surfactant: reduces surface tension/sticking together, keeps alveoli open

respiratory membrane

barrier between aleveolar air and blood surrounding capillary

gas exchange 

Squamous Alveolar cells

type 1 pneumocytes

95% of alveolar surface area

thinness allows for rapid gas exchange 

Great Alveolar Cells

type 2 pneumocytes

repair damaged alveolar epithelium

secrete pulmonary surfactant 

right lung

3 lobes

left lung

2 lobes, smaller room for heart

Pathway of Air

conducting division: mouth, pharynx, larynx, trachea, main bronchus, lobar bronchus, segmental bronchus, bronchiole, terminal bronchiole: respiratory division, respiratory bronchiole, alveoli

Hemoglobin

oxygen binds to iron (heme in middle)

co2 binds to globin units 

Inspiration

movement of air into lungs

diaphargm flattens, ribs/intercostal muscles contract 

increase in volume/size=decrease in pressure: air rushes in

Expiration

movement of air out of lungs

diaphragm and intercostal muscles return to resting postiion reducing size of thoracic cavity, air forced out: increased pressure 

Low pressure=

low resisteance

big spaces have low pressure/resistence 

fits lots of air 

low inrapulmonary pressure compared to atmospheric

air flows in, decreased lung pressure

high intrapulmonary pressure compared to atmospheric

air pushed out, increased lung pressure

Determinants of Effective Breathing

rate, depth, minute ventilation (TVx rate= total vent. per min)

2 sources of pulmonary regulation

central (brain), peripheral

Central Regulation

respiratory centers: medulla oblongata, pons

central chemoreceptors are stimulated by 

1) increase of Co2 (main thing)

2) decrease in pH (acidity)

3) low o2

uses negative feedback

Peripheral regulation

chemoreceptors= monitor blood gases and pH to adjust breathing: CO2, o2, ph

aortic arch/carotid bodies

• anxiety is a result of sympathetic stimulation

• hyperventalation, co2 drops, parasympathetic fixes

Relaxed Breathing

inhalation: diaphragm contracts downward /external intercostals contract

exhalation: muscles relax passive exhalation occurs  

Foreced Breathing

look on pp