Breathing

Conditioning the air

Gas Exchange

Produces Sounds

Detects olfactory stimuli 

Air Warmed to Body Temperature

Air Moistened

Air Filtered with removal of particulate matter 

moving air into and out of the lungs 

gas exchange between the lungs and the blood 

Nasal cavity

Pharynx

Larynx

Trachea

Primary bronchi, Secondary bronchi, tertiary bronchi

Bronchioles

Alveoli (150 million/lung) 

Upper Respiratory Tract

       Nasal cavity, pharynx

Lower Respiratory Tract

       Larynx, trachea, primary bronchi, secondary bronchi,        tertiary bronchi, bronchioles, alveoli 

Conducting Zone: bring air to the site of external respiration 

     Includes the nose, pharynx, larynx, trachea, bronchi,        bronchioles, and terminal bronchioles 

Respiratory Zone: primary site of gas exchange 

     Includes respiratory bronchioles, aveolar ducts, aveloar      sacs and alveoli 

Internal-in skull, above roof of mouth

External-protruding from face: "danger zone of face"

Right and left nostrils separated by septum formed by perpendicular plate of ethmoid, vomer, vomeronasal and septal cartilages

n  Skin is thin-contains many sebaceous glands

External nares-nostrils

Divided by-nasal septum

Vestibule-anterior opening

Continuous with nasopharynx

Near roof of nasal cavity, houses olfactory smell receptors

-Lines nasal cavity 

-Epithelum is pseduostratified cilated columnar

-Goblet cells within epithelum 

-Underlying layer of lamina propria has mucus secreating glands; blood vessels that warm air

-Cilia move contaminated mucus posteriorily 

-3 paired bony projections along the lateral walls of the nasal cavity

-superior and middle nasal conchae-part of the ethmoid bone

-inferior nasal conchae-separate bone

-Function-particulate matter deflected to mucus coated surfaces 

Divisions-nasopharynx (behind nose) oropharynx (behind mouth) and laryngopharynx 

Four in nasopharynx (2 auditory tubes and 2 posterior nares)

One in oropharynx (fauces of mouth)

Two in laryngopharynx (open into esophagus and larynx) 

Adenoids (pharyngeal tonsils in nasopharynx; palatine and lingual tonsils in oropharynx 

-Composed of 9 pieces of cartialge arranged in boxlike fashion

-Contains vocal cords

Lining-pseudostratified cilated columnar epithelium

Function-expired air causes true vocal cords to vibrate producing voice; pitch determined by length and tension of cords 

True Vocal Cords

-Infolding of the mucosa

-attached to laryngeal muscles

-act in sound production 

False vocal cords 

-no role in sound production 

-Length of vocal cords changes with pitch

-loudness depends on the force of air across the vocal folds 

-descends into the mediastinum

-walls of smooth muscle with C-shaped cartilage rings that keep airway open 

-epith-pseudostratified ciliated columnar

-function-passageway for air going to and from the lungs

-divides into primary bronchi 

-formed by division of trachea into two tubes

-right bronchus slightly larger and more vertical than left 

§  Primary bronchusàsecondary (lobar) brinchiàtertiary (segmental bronchi)àbronchiolesàterminal bronchiole (lobule)

-function-bronchi and its branches furnish passageway for air to and from lungs 

Primary (main)

   -one to each lung

Secondary

    -three in right lung

    -two in left

Tertiary

    -branch into each lung segment

    -10 per lung

-less than 1 mm in diameter

Terminal bronchiole

  -less than .5 mm in diameter

  -1 per lobule 

Tissue Composition of Conducting Zone 

(supportive connective tissue changes) 

Changes along pathway

  -supportive connective tissue change

  -C shaped hyaline cartilage rings-trachea

  -most complete rings-primary bronchi

  -replaced by cartilage plates in secondary and tertiary bronchi 

Tissue Composition of Conducting Zone 

(epithelium changes)

First, pseudostratified ciliated columnar-trachea

simple columnar-bronchi 

simple cuboidal epithelium-bronchioles and terminal bronchioles 

Smooth muscle becomes important at the bronchioles-controlled by automatic nervous system (bronchoconstriction and bronchiodilation) 

functional unit of the lung

-each pulmonary lobule contains a lyphatic vessel, a arteriole, a venule and terminal bronchiole with its branches of the respiratory bronchioles, alveolar ducts and alveoli 

-cell types

   Type I-simple squamous epith-site of gas exchange 

   Type II-secrete surfacant

   Macrophages 

-surrounded by loose connective tissue, capillaries

-interconnect by way of alveolar pores

-internal surfaces-site for free movement of alveolar macrophages 

Lined with simple squamous epithelium supported by a thin elastic basement membrane 

Layer of type 1 alveolar cells (simple squamous) fused

Basement membrane underlying type 1 cells

Basement membrane of the capillary blood vessel

Simple squamous epith (endothelium) of capillary 

Branch to form alveolar ducts (lined with simple squamous epithelium) 

Alveolar ducts lead to alveolar sacs(with 2 or more alveoli) 

A double layered sac surrounded each lung

   -parietal pleura

   -visceral pleura

Pleural cavity

   -pleurae help divide thoracic cavity 

Owing to the structure of lung alveoli there is about 750 sq ft of respiratory membrane specialized for gas exchange 

-site for exchange of oxygen and carbon dioxide between the air spaces in the lungs and blood of underlying capillary

Because flat cells for gases to go through

1. The differance in partial pressure across the respiratory membrane
2. The distance across the membrane is short
3. The gas (O and CO2) are lipid soluble 
4. The total surface area of the respiratory membrane is large
5. Blood flow and air flow are coordinated 

-Pulmonary and bronchial arteries: carry blood from the heart to the lungs

-bronchial arteries supply the lung tissue with O2 blood. Need O2 for life

-Pulmonary arteries bring deoxygenated blood to the left and right lungs

    -pulmonary veins return oxygenated blood to the left atrium of the heart 

-Process by which blood is specifically directed to oxygenated areas of lung tissue for pick up of oxygen and away from deoxygenated areas of the lung 

-in all other body tissues, hypoxia causes dilation of blood vessels to increase blood flow because pulmonary veins return oxygenated blood to left atrium of the heart 

-low O levels in lung tissue induces vasoconstriction of the pulmonary blood vessels

-diverts blood from poorly ventilated area to well ventilated areas in the lung 

N2=78.6%

O2=20.9%

CO2=.004%

Water vapor=.3% varies greatly day or region of country 

At sea level, the air pressure is:

 14.7 lb/in² = 1 atm

760 mmHg = 1 atm

Pressuer of gas is inersly related to size of container (Vol=1/P) 

-If there is a decrease in volume there will be an increase in P

-Applies to containers with flexible walls (such as thoracic cavity) 

-In a mixture of gases the pressure of each gas is directly proportional to the percentage of that gas in the total mixture 

PT=P1+P2+P3

-each gas diffused from an area where it is partial pressure is greater to an area where its partial pressure is less

-the rate of diffusion is proportional to the diff in partial pressure between the areas

the quantity of gas that will dissolve in a liquid is proportional to the partial pressure of that gas and its solubility 

-the higher the partial pressue of a gas over a liquid and the higher solubility the more gas will dissolve/stay in soln 

- The sol if CO2 in plama is 24X that of O2 hense much more CO2 thatn O2 is dissolved in plam

-Although P(N2) is high its insol in plasma 

Exchange of gas

External: occurs between pulmonary tissues (alveoli) and blood

Internal: occurs between blood (capillaries) and body tissue 

 Requires-pulmonary ventilation and vascular transport of gases 

Contraction of diaphragm and external intercoastal muscles

Air is drawn into the lungs (alveolar P is 758 mmHg)

Relaxation of inspiratory muscles- opposite effect (thoracic cavity decreased)

Contraction of the diaphragm and ext. intercostals are responsible for 75% and 25% respectively of air movement during quiet breathing 

-collapsed lung; normally surfactant prevents alveoli from collapsing 

• ease with which lungs and thoracic wall expand; related to elasticity and surface tension 

bronchi and bronchioles dilate upon inspiration decreasing resistance to airflow; obstructions increase resistance 

·      at rest the avg air expired after normal inspiration (500ml)

   amount air forcibly inspired after normal inspiration (3100ml)

·      (ERV) – additional amount of air that can be forcibly expired after normal inspiration/expiration; (1200 ml)

the measurement of lung capacity

  – largest vol of air an individual can move in and out of lungs; (IRV+TV+ERV=4800ml)

·      (RV) –amount of air that cannot be expired; 1200 ml

·      vol of air filling nose, pharynx, larynx, ect. But does not descend into alveoli; doesn’t take part in gas exchange (30% of TV-150 ml)

deep abdominal breathing; due to contraction of diaphragm 

o   During deep labored inspiration sternocleidomastoid, scalenes, and pectoralis minor may assist inspiration

the amount of effort required to stretch the lungs and chest wall 

o   Low-lung/chest resist expansion

o   The connective structure of the lungs

§  Presence of scar tissue (tuberculosis)

o   Filling of the lungs with fluid

o   Level of surfactant production

Mobility of thoracic cage