KNES 191A Respiratory Exam

Functions of respiratory system

• gas exchange atmosphere (CO2) and body cells (diffusion)

• moving air to and from the lungs

• regulate blood pH

• protection from temp change, dehydration, pathogens

• produces sound (vocal chords part of RS)

• helps w/ sense of smell

4 events of Respiration

• movement of air in and out the lungs

• gas exchange (diffusion) between lungs and blood/ external respiration

• gas transport between lungs and body cells

• gas exchange (diffusion) between blood and body cells (tissue)/ internal respiration

upper tract: nostril

open so air can enter and exit the nasal cavity

upper tract: nasal cavity

• air passes through mucous membrane > heat leaves the blood and warms the air > adjusting body temp

• incoming air moistened and sticky > creates mucus which traps dust and particles

upper tract: paranasal sinuses

• air filled space located within certain bones of skull

• decrease weight of the skull

• contribute to create the unique voices people have

upper tract: pharynx (throat)

• provide passageway for food entering from mouth to esophagus and for air passing between nasal cavity and larynx

• help produce sounds for speech

lower tract: larynx

• conduct air in and out of trachea through glottis

• the cartilage structure surrounds and protects the glottis

• prevents stuff from entering trachea and vocal chords

• the epiglottis is a flap like structure allowing air to enter larynx, located superior to the glottis and form a lid over it

• sound is produced by forced airflow through the glottis between true vocal cords causing vibration

• False vocal cords control tension in cords by sealing off the glottis when swallowing

lower tract: trachea (windpipe)

• flexible tube extending down anterior to esophagus

• extend into throat cavity and split into L and R bronchi

• trachealis muscle and connective tissue fills the gaps to allow the diameter of trachea to change during inhalation and exhalation

lower tract: bronchial tree

• has branched airways that lead to smaller air sacs (alveolus) in the lungs

• ORDER: Trachea>primary bronchi>secondary bronchi>tertiary bronchi>bronchioles> terminal bronchioles(getting air to cells)>lung

lower tract: lungs

• has lobes that are divided -RIGHT lung has 3 LOBES> superior, inferior, middle

• LEFT lung has 2 LOBES> superior and inferior -Walls/Layers of Lung;

• Pleural membrane; protects lungs with double layer -Visceral pleural; attached to lung tissue>deeper

• Parietal pleural; closer to the ribs> forms double walled sacs

• Pleural Cavity; space between visceral and pleural> consists of fluid that creates surface tension(makes things sticky)

SNS=Bronchodilation

• >INC diameter of bronchioles that causes INC in airflow

• PCO2 INC = dilation of bronchioles

• need wider tubes

• fight or flight

PNS=Bronchoconstriction

• >DEC diameter of the bronchioles and DEC airflow

• PCO2 DEC=constriction of bronchioles

• don’t need tubes -more difficult to breathe

• at rest > breathing slower

Mechanism of Breathing

• pressure from air moves into the lungs following INC and DEC of pressure

• lungs need to match pressure

Expanding Lungs=inspiration

• VOL INC and PRESSURE DEC

• intra-alveolar pressure decreases to 758mmHg, creating a pressure gradient for air diffusion into lungs

• Lower lung pressure draws air from outside(HIGH pressure/inhaling) to lungs

• Resting Inhalation works; diaphragm and external intercostals

• Forceful inhalation works; sternocleidomastoid, scalene, pectoralis minor

Recoiling Lungs=expiration

• VOL DEC and PRESSURE INC -thorax vol DEC and lung pressure INC to about 262 mmHg, a little above atmospheric pressure

• higher lung pressure expels air from inside lungs (higher pressure) to outside the body (lower pressure/exhale)

• Resting Exhalation makes; diaphragm/external intercostals relaxed

• Forceful Exhalation works; abdominal wall/internal intercostals(makes lungs smaller)

Effect of Altitude on Breathing > Effect on gradient for O2

• DEC in ALT= INC P (CO2) -INC in ALT- DEC P

• Deoxygenated blood always going to be 40mmHg

• Pressure in environment DEC so does PO2 & PAO2(arteral)

• at HIGH ALT breathing becomes more difficult due to SLOWER diffusion of oxygen from the alveoli into blood (less O2 into blood)

Tidal Volume

resting volume/normal breathing

Residual Volume

air remain in the lungs all the time

Inspiratory Reserve Volume

biggest inhale/forced inspiration

Expiratory Reserve Volume

largest exhale/forced expiration

Vital capacity

Biggest inhale + Biggest Exhale

Total Lung Capacity

vital capacity + residual volume (adding up all the volume)

Gas Exchanges at Respiratory Membrane

• alveoli exchanges gas between air and blood

• breathing supplies alveoli with O2 and remove CO2 from the bloodstream

What is the respiratory membrane?

space between the two sites of gas exchange (alveoli and capillary)

Which direction does diffusion of each gas occur and why?

• O2 will diffuse from LUNG into BLOOD stream due to HIGH partial pressure in lung and when diffused into blood, LOWers partial pressure of O2

• CO2 diffuses from BLOOD stream into LUNGS due to HIGH partial pressure in bloodstream and when diffused into lungs, lowers partial pressure of CO2

• Gas exchanges occur and transition into oxygenated blood into the rest of the body

Atmosphere air

• all contribute to total pressure which contributes to partial pressure

• 78% nitrogen

• .04% CO2

• .5% H2O

Henry's LAW

• the Amount of PO2 that reaches the lungs, will be the same amount that goes into blood due to a pressure gradient

• Blood partial pressure will ALWAYS match the partial pressure inside the lungs

• whether at REST or EXERCISE, partial pressure in lung and blood stream still be the SAME

• In capillary, deoxygenated blood is returning to lungs -PO2 DEC, PCO2 INC

• In lungs air, oxygenated blood returned -PO2 INC, PCO2 DEC

• When oxygenated blood leaves the lungs -PO2 INC, PCO2 DEC

Tissue to blood (CO2 pick up)

1. CO2 diffuses into RBC

2. CO2 + H2O= carbonic acid> dissociates and splits apart into H+ HCO3-

3. Carbonic Acid losing H creates Bicarbonate ion

4. Bicarbonate ion travels outside RBC to dissolve into plasma

Blood to Lungs (CO2 delivery)>REVERSE process

1. Bicarbonate ion travels into RBC where it’s Cl- moves out

2. H+ attaches to bicarbonate ion to make carbonic acid

3. Carbonic acid removes its H2O to make CO2

4. CO2 diffuses into lungs to be exhaled out

Local Regulation(adjustment of blood flow and bronchiole diameter=automatic)

The rate of O2 delivery in each tissue and the efficiency of oxygen pickup at the lungs regulated at the local level

The effect of local metabolic activity

• As metabolic activity INC, the segment of PO2 DEC and PCO2 INC> causing size of the gradient in partial pressure for tissue and arriving blood INC

• Rate of diffusion partially dependent on size of gradient>cause more O2 to be delivered and CO2 to be carried away ● More diffusion>higher the CO2

Lung Perfusion

Where deoxygenated blood gets routed into lungs

Alveolar Ventilation

Incoming air routed into the lungs

Ventilation-perfusion Coupling

• As deoxygenated blood flows towards capillaries of lungs>where it goes to lobes of lungs where PO2 is high due to vasoconstriction of capillaries in areas of low PO2

• when PCO2 INC=bronchodilation(SNS)

• when PCO2 DEC=bronchoconstriction(PNS)

• resulting in air flow directed to lobules where PCO2 is high

Medullary Respiratory Center

Neurons that help regulate breathing

Dorsal Group (DRG)

• responsible for normal rhythm of breathing> used inhalation muscles

• Makes breathing faster or slower> sends impulse>gets faster>impulse stops causing exhalation>VRG kicks in inhalation muscles

Pre-Botzinger Complex

• group of neurons located with Ventril R group(responsible for faster breathing)>uses exhalation muscles

• Normal resting breathing=VRG inactive

• Labored breaking> DRG acivitae VRG to activate inhalation/exhalation muscles

Pontine Respiratory Group (PRG)

• Transmits impulse to DRG

• Modifies/tunes breathing rhythms made by VRG during activities like speaking, sleeping, exercising

• Gets input from higher brain center and other receptors

Chemoreceptors(chemical changes)

• Sensitive to: monitors changes in PO, CO2, PO2, H+, CSF

• Location: near your baroreceptors

• Peripheral chemoreceptors(in carotid/aortic arteries) monitor low O2 levels or DEC in blood pH>stimulated by a rise in CO2

• Central chemoreceptors(near medulla) monitors CO2 and H+>when levels of those two are elevated>senses changes in CSF

Baroreceptors(BP changes)

• Sensitive to: BP and BV> when BP falls> respiratory rate INC, when BP rises> RR DEC

• Location: near chemoreceptors/walls of bronchioles

Hering-Breuer Reflexes (inhalation/exhalation)

• the inhalation (inflation) reflex is triggered by lung expansion, inhibiting further inspiration and promoting expiration, while the exhalation (deflation) reflex is triggered by lung deflation, stimulating inspiration and inhibiting expiration

• Inhalation: prevent over inflation of lungs

• Exhalation: ensures proper breathing by prompting next breath

Neural Regulation

When activity levels increase and the demand for oxygen rises, the cardiac output and respiratory rates increase under neural control

Exercise and Respiratory System

• Training improves performance by enhancing cardiovascular and respiratory efficiency with delivering O2 and CO2 removal

• After training, vital capacity INC slightly and residual volume DEC slightly

• During exercise, changes in ventilation include depth and rate of breathing>depth increase more than rate

Factors that stimulate INC in breathing during Exercise

1. Learned responses (ventilation INC within sec)

2. Neural input from the motor cortex (stimulates the muscles)

3. Proprioceptors (move muscles and joints)

4. INC in body temp

5. Circulating epinephrine & norepinephrine

6. pH changes

Compliance

- the ability of the lungs and thoracic cage to expand and recoil during respiration (not as elastic anymore)

Respiratory System DEC due to

• Deterioration of the lungs elastics tissues> results in lowered vital capacity due to DEC in compliance

• Limitation in chest movements due to arthritic changes in rib articulation

• Emphysema is present in individuals over 50 years of age (considered normal)