Know your basic parts Supply the body with Oxygen Dispose of Carbon dioxide

Know your basic parts

Supply the body with Oxygen Dispose of Carbon dioxide

Respiratory zone:◦ Actual site of gas

exchange◦ (some exchange -

Respiratory bronchioles, alveolar ducts) alveoli (major site)

Conducting zone:◦ Conduits – purify,

humidify, and warm incoming air

◦ Include all other respiratory passageways

Provide airway for respiration

Moisten & warm air Filter air (mucus & cilia)

(breath in thru nose & out thru mouth)

Site of olfactory (smell) receptors

Resonating chamber for sound waves (hold your nose closed & see how you sound!)

Mucus traps the “junk” and the cilia sweeps it up toward your throat so you can swallow it or spit it out.

Smoking kills cilia so smoker’s constantly have to cough to clear the mucus out!

The cilia in your nose become sluggish & slow when they are cold & do not move the mucus down into your throat

Mucus in the nasal cavity accumulates & dribbles out

Nasal Conchae aka. NasalTurbinates= increase SA of mucosa exposed to air to help warm & filter it – also increase turbulence (mini tornado effect) of air – more inhaled particles swirled onto mucus and trapped

Nasal cavity separated from oral cavity by the palate (roof of mouth)◦ Anterior – hard

palate◦ Posterior – soft

palate

Lighten skull Act a resonance chamber Produce mucus

Pharynx serves as common passageway for food (& fluids) and air.

Color code the 3 parts of the pharynx on the diagram in your notes

The names give you location clues!

Nasopharynx – air only◦ During swallowing, Soft palate & uvula rise

upward to close off nasopharynx which prevents food & fluids from entering it

Oropharynx & Laryngopharynx – food, liquids & air◦ Food will be directed posteriorly to the

esophagus◦ Air will go anteriorly into the larynx

Pharyngeal tonsils: aka. Adenoids – located in nasopharynx

Palatine tonsils: located in oropharynx Lingual tonsils: located at base of tongue All tonsils are lymph nodes & work with

immune system You will be labeling these on the back page

diagram

Provides patent (open) airway

Act as a switching mechanism (between respiratory & digestive systems)

Voice production (location of vocal cords)

Know this: Laryngeal prominence on the thyroid cartilage

Seen externally as Adam’s apple

9th cartilage When air is flowing into the larynx – free

edge projects upward During swallowing:

◦ Larynx is pulled upward◦ Epiglottis is tipped back and down to cover

laryngeal inlet into trachea◦ Routes food/fluid into esophagus

Initiated if anything other than air enters the larynx

Pressure from air moves object upward out of the larynx◦ Reflex does not work when unconscious so not a

good idea: To give fluids to an unconscious

person Also a reason why people in an

alcoholic coma often die from aspirating their own vomit.

The ciliated mucosa (mucociliary escalator) continuously propels the mucus which contains dust particles and debris to the throat so it can be expelled or swallowed.

Diminishes ciliary activity Coughing is ONLY method of preventing

mucus accumulation in the lungs Smokers should never be given medications

that INHIBIT the cough reflex.

Trachea is reinforced internally by 16-20 C shaped rings (Be able to explain – see diagram on next slide also)

Outer portion of C – causes trachea to stay patent (open) and not collapse

Inner portion (open part) of C – allow trachea to be flexible and gives esophagus a place to expand into upon swallowing.

Heimlich manuver is the same principle as a cough

Used to press air out of lungs in case someone cannot inhale to initiate a cough

-ostomy = cut a hole into Used in cases of:

◦ Abnormalities◦ Cancers◦ Obstructions◦ Injuries to area◦ Etc.

Trachea divides into right and left primary bronchi at the level of the sternal angle (where manubrium and body of sternum meet).

Inhaled objects usually lodge in the right primary bronchus since it is wider, shorter, and at a more vertical angle

Left lung is smaller, consisting of 2 lobes and contains a cardiac notch

Right lung has 3 lobes FYI: Bronchopulmonary segments

◦ Served by own artery, vein, and individual segmental bronchus

◦ Left lung has 8 segments while right lung has 10.

Respiratory therapists and surgeons use this info about the different bronchopulmonary segments so they can treat the patient as needed◦ Even to the point of removing the diseased

segment and leaving the good tissue

The lungs weigh approximately 2.5 pounds

Parietal vs. visceral Function of pleural fluid

◦ Lubricate layers so they can slide across each other

◦ Cause them to cling tightly to each other through surface tension (helps maintain pressure differences necessary for inhaling/exhaling)

Begins as the terminal bronchioles which feed into the respiratory bronchioles which end in the alveoli chambers where gas exchange (external respiration) takes place.

Composed of simple squamous – much thinner than a sheet of paper

Membrane has gas on one side and blood on the other.

Account for the largest portion of lung volume and provide a tremendous surface area for gas exchange

Gas exchanges occur through simple diffusion

Approximate surface area = 50-70 square meters (40x greater than skin SA)

A moist membrane is required so the TYPE II cuboidal cells secrete a substance called surfactant that coats the membrane & interferes with surface tension.

Pulmonary ventilation: air is moved in and out of the lungs

External respiration: gas exchange between blood and alveoli

Respiratory gas transport: CV system transports oxygen and carbon dioxide between lungs & tissues (discussed in Blood chapter)

Internal respiration: gas exchange between blood & tissue cells Definition: Cellular respiration: actual use of

oxygen & production of carbon dioxide in the cells (this is why we have to breathe!!)

Pulmonary ventilation: - Moving air into and out of the lungs Depends on pressure changes Breathing Inspiration = moving air into the lungs Expiration = moving air out of lungs

Intrapulmonary pressure Pressure within the alveoli (lungs) Changes with phases of breathing Always equalizes itself with atmospheric

pressure Intrapleural pressure

Pressure within intrapleural space (between the pleural membranes )

Always 4 mmHg less than intrapulmonary pressure

Any conditions that causes intrapulmonary pressure to equal intrapleural pressure will cause the lungs to collapse

This means they lose the ability to move air since there is NO more pressure difference

term for lung collapse

Air in the intrapleural space due to trauma – causes lung collapse

Question: Why does breathing happen? ONLY acceptable answer: The RULE:

Volume changes lead to pressure changes which lead to the flow of gases to equalize the pressure

Boyle’s Law = Pressure & Volume have an INVERSE relationship.

Main inspiratory muscles Diaphragm & external intercostals

Thoracic dimensions change to increase volume of thoracic cavity by 0.5 liters

Intrapulmonary pressure drops 1-3 mmHg and air rushes info normal quiet inspiration

A deep forced (active) inspiration requires activation of accessory muscles – see diagram in notes

A passive process dependent on natural lung elasticity

lungs recoil when inspiration stops – so alveoli compress –which leads to a volume

decreases -causing intrapulmonary pressure to rise - gas outflows to equalize the pressure with atmospheric pressure

Forced (active) expiration requires contraction of abdominals, etc – see diagram

Bronchial sounds: produced by air rushing through trachea & bronchi

Vesicular sounds: produced by air filling alveoli

Wheezing: whistling sound

Rales: rasping sound

Basic Lung Sounds – Bronchial Auscultating The Lungs - Reference Guide

Pulmonary ventilation can be influenced by 4 physical factors Respiratory passage resistance Lung compliance Lung elasticity Alveolar surface tension forces

Resistance due to increased friction as air moves through passages Smooth muscle

bronchoconstriction Disorders such as asthma – when bronchi constrict

Local accumulations of mucus, infectious material, and tumors – also block air passage

The ease with which lungs can readily expand

Affected by the elasticity of the lungs and the thoracic cage which can be diminished by 2 main factors: Fibrosis of the lung tissue Ossification and/or muscle paralysis impairs

flexibility of the thoracic cage

Essential for normal expiration

Emphysema: tissue becomes less elastic and more fibrous loss of elasticity & increase in fibrous tissue

causes enormous effort to exhale – at end stages, alveolar walls break down and surface area is lost for gas exchange

Surface tension is caused by the tendency of polar molecules such as water to stick to each other with hydrogen bonds

this can cause the walls of the alveoli to stick together like plastic wrap every time you exhale.

Large amounts of energy /effort will be required to simply re-expand the lungs and

allow you to inhale (IRDS)

Surfactant – interferes with cohesion of water molecules so less energy needed to expand lungs – this is one of the things that keeps our lungs partially expanded at all times. (the other thing is the pressure difference previously discussed)

Secreted by Type II cells in lungs

AKA: Hyaline Membrane DiseaseCaused by lack of surfactant due to prematurity 28 weeks of gestation is considered

Measurements made as part of pulmonary function tests;

Volumes that move in and out during the normal breathing cycle, and with deliberate additional effort

can be measured directly by spirometry with the subject breathing through a closed circuit in and out of a cylinder inverted over water, or into a vitalograph, or by pneumotachograph

Table 1: Lung volumes

Tidal Volume Volume of inspired/expired air moving in and out with each breath

Inspiratory and expiratory reserve volumes

Used when tidal volume increases above that at rest

Vital capacity Volume that can be inspired/expired after full expiration/inspiration

Forced expiratory volume in1s

Volume exhaled in the first second, with maximal effort after full inspiration

Functional residual capacity

Volume remaining in the lungs at end-expiration; decreases as tidal volume increases

Residual volume Remains after a maximal expiratory effort; cannot be exhaled

Total lung capacity Vital capacity + residual volume

Internal & External RespirationEvents #2 & 4

Used to determine the individual pressures of each gas in a mixture of gases

Based on % of total of 760 mmHg of total atmospheric pressure

Gas exchanges that occur: Between the blood and the alveoli AND Between the blood and the tissue cells Take place by simple diffusion Depends on partial pressures of oxygen & carbon

dioxide that exist on opposite sides of the exchange membrane (Dalton’s law of partial pressures)

Always flowing from high to low

states that the solubility of a gas in a liquid is directly proportional to the pressure of that gas above the surface of the solution (IOW: the higher the pressure of the gas, the more gas will be shoved into the liquid thus increasing solubility)

Solubility (of a gas) and partial pressure have a direct relationship

The solubility coefficient of the gas also affects this process – the higher the #, the more the gas “likes” to dissolve into a liquid (based on molecular structure, etc.)

Each gas will dissolve in a liquid in proportion to the ratio between its partial pressure gradient and its solubility coefficient CO2 = .57 O2 = .024 N2 = .012

Solubility & temperature have an inverse relationship.

Increase in temperature causes increase in kinetic energy causes more molecular motion which allows molecules to break the intermolecular bonds and escape from solution

And vice versa

Partial pressure gradients and gas solubilities Oxygen = has low

solubility but steep partial pressure gradient (105 mmHg in alveoli – 40 mmHg in blood = 65 mmHg pressure gradient)

Carbon dioxide = has solubility ~20x greater than oxygen but partial pressure gradient is only 5 mmHg

Partial pressure gradients and gas solubilities Due to the ratios of solubility coefficients and

pressure gradients: ~Equal amounts of gases are exchanged

Thickness of respiratory membranes 0.5 to 1.0 micrometers edematous (swollen) tissue can be caused by

congestion and pneumonia - hinders diffusion leading to hypoxia oxygen deprivation

Surface Area 50-70 square

meters for gas exchange

Emphysema or cancer

Walls of alveoli break down

Less surface area for gas exchange

The phrenic & intercostal nerves transmit impulses to the respiratory muscles Irritation to phrenic

nerve is responsible for hiccups (spasm of diaphragm muscle)

Neural centers are located in medulla & pons

Eupnea = normal respiration rate Approx 12-15 breaths per min

Hyperpnea = higher than normal rate Apnea = No rate Dyspnea = general term for abnormal rate Physical factors, conscious control,

emotional factors, and chemical factors all influence rate & depth of breathing.

Deep & rapid respiration, too much CO2 is vented out of the body so:

Not enough acid productionH2O + CO2 = H2CO3 (carbonic acid)

Respiratory alkalosis results Treatment: trap the CO2 and

rebreathe it till breathing returns to normal

Slow & shallow respiration with not adequate expiration so CO2 is not vented out of the body

Production of excess acid H2O + CO2 = H2CO3 (carbonic acid)

Respiratory acidosis results Usually caused by disease process:

COPD Asthma Obesity Trauma Pneumonia