Chapter 18 Respiratory Sys

main components of respiratory sys

Nasal cavities, Pharynx (thorax), Larynx (voice box), Trachea (windpipe), Bronchi, Lungs, Pleura space

Nasal Cavities

Nostrils (nares) - air enters through openings in nose into nasal cavities

Nose Breathing - preferred over mouth breathing because it filters air

Mucous Membranes - filters foreign bodies + moistens + warms air; in nasal cavities

Conchae - shell-like projections located w/in each nasal cavity that increase surface area of mucous membranes

Nasal septum - separates the two nasal cavities

4 Phases of Respirations

Pulmonary Ventilation, External Gas Exchange, Gas Transport, Internal Gas Exchange

1.) Pulmonary ventilation

exchange of air btw atmosphere + air sacs (alveoli) of lungs accomplished by inhalation + exhalation

2.) External Gas Exchange

occurs in lungs as O2 diffuses from air sacs into blood + CO2 diffuses out of blood to be eliminated

3.) Gas Transport

happens in the blood

4.) Internal Gas Exchange

occurs in the tiss as O2 diffuses from blood cels + CO2 passes from cells to blood

Pharynx (throat)

carries air to resp tract + food to digestive system

lined w/ mucos mem; divided into NASOPHARYNX (superior) , OROPHARYNX (middle; located posterior to mouth, tonsils on either side), LARYNGEAL PHARYNX (inferior; opening into lar towards anterior + into esophagus towards posterior)

Larynx (voice box)

btw pharynx + trachea

cartilage framework from C rings supports + keeps trachea + larynx open

Adams apple is formed by thyroid cartillage

vocal cords folds of mucous mem (used for speech, located on both sides of superior port of lary

Glottis + Epiglottis

Glottis + Epiglottis

G - space btw vocal cords

E - leaf shaped cart covers larynx during swallowing (prevents food + fluid from entering trachea

Bronchi

trachea divides two primary bronchi that enter lungs

right bronchus has LARGER DIAMETER + is more downwards than LEFT bronchi

Hilum - notch or depression where bronchus enters lung

Epithelial Tiss lining (have cilia to filter out impurities + move fluids

Trachea (windpipe)

conducts air btw larynx + lungs

cartilage are horse shaped or C shaped (@ back for swallowing)

divides into bronchi

Diaphragm

largest muscle of resp, seperates thoracic + abdominal cavity

neck + abd mus + intercoastal mus (btw ribs) involved in forced exhalation

contracts during pulmonary ven

Lungs

on either side of mediastinum in thoracic cavity (lungs are NOT mediastinum)

Medistainum

middle compartment of chest btw lungs

contains heart, great vessels (aorta), lymp nodes, thymus, esophagus, trachea + phrenic nerves

Pleura

serous mem that is a ct tiss double sac that covers lungs

Parietal pleura

attaches to chest wall

Visceral pleura

(ORGANS) surronds lung surface

Pleural space

area btw 2 layers of pleura that contains thin film of fluid that lub mem

Bronchus

enters each ling + subdivides into each lobe

lobes

RIGHT = 3 lobes

LEFT = 2 lobes

bronchioles have no cartilage

Alveoli

air sacs where gas exchange occurs

Inhalation (inspiration)

active phase of drawing air into lungs

surfactant

allows lungs to expand under pressur

compliance

(elasticity) ease that lungs expand in thorax

exhalation (expiration)

passive phase occurs when respiratory mus relax allowing ribs + diaphragm to return to original positions

Process of Respiration

exchange of oxygen + CO2 btw lungs + environment

ventilation of lungs

exchange of gases

transport of gases in blood

needs are met by central + peripheral controls

during labored breathing

retractions btw ribs (intercostals) may be seen when using accessory muscles

when someone is Dyspneic

Dyspneic

feelings of shortness of breath, needing more air

Gas Exchange

requires gradient; diffusion (high to low gradient)

External Exchange (external respiraiton lungs)

oxy leaves lung alveoli then enters capillaries (molecules of O2 moves from air sacs to blood; btw alveoli + blood

1. CO2 leaves capillaries then enter alveoli; CO2 moves from blood to air sacs

2. resp mem is thin +moist (imp bc O2 + CO2 must go into solution before they can diffuse across mem

Internal exchange (internal resp)

interchange btw body tiss + capillaries; btw blood + cells

1. oxy leaves cap + enters tiss

   1. CO2 leaves tiss + enters cap

Lung capacity

sum breathing vol + capacities

Tidal volume

vol air moved in + out of lungs in quiet breathing

inspiratory reserve vol

am that can be forced in after norm inhalation

expiratory reserve vol

amount that can be forced out after norm exhalation

residual vol

vol of air that remains in lungs after max exhalation

vital capacity

vol of air expelled from lungs w/ forceful exhalation following max inhalation

functional residual capacity

vol of air remaning in lungs after norm exhalation

total vol capacity

air vol in lungs after max inhalation

spirometer

an instrument used for recording lung vol (tracing is seen on spirogram - graph that tracks vol of air moving in + out lungs over time

Transport of CO2

CO2 diffuses from cells into blood + is transported to lung in three ways

1. 10% dissolved in plasma + fluid in RBC (am of CO2 dissolved in plasma is imp in regulating acid-base balance

2. 15% combined w/ protein of HBG + plasma proteins

3. 75% dissolves in blood fluid, is converted to bicarbonate ion + transported lungs

   1. most CO2 is transported HCO3 (bicarbonate ion)

Carbonic anhydrase

enz speeds conversion of HCO3 inside RBC

bicarb ion is important buffer in blood (keeps pH steady)

Oxygen Transport

• most O2 (98.%) transported in blood by hemoglobin

• hemog mole has 4 small iron-containing “heme” regions (1 mole of oxy binds to “heme”

  • 4 heme 1 oxy per heme

Oxygenated blood

in systemic arteries + pulmonary veins saturated w 97% oxy

oxy must be seperated from hemog to enter cells

Hematocrit test (HCT)

measures the % of whole blood vol that is made up of RBC

Deoxygenated blood

in systemic veins + pulmonary arteries contains about 70% of oxy

carbon monoxide (poisonous gas)

binds at same sites as O2 and decreases blood’s ability to carry O2

Regulation of Res (REG of Ven)

complex process that requires constant changes to meet demands

controlled by CNS sys (pons + medulla regulate resp)

• resp contrl centers located in brain stem (medulla + pons)

• main control center in medulla sets pattern

what regulates respirations

Pons + medulla in the brain

• resp control centers located in brain stem (medulla + pons)

• main control center in medulla sets pattern

• pons modifies patters set by medulla

modified by receptors, keep oxy + CO2 within norm limits

CO2 affects acid base balance acidosis + alkalosis

Acidosis

Increased CO2, decreases blood pH

Hypoventilation

Alkalosis

increased blood pH

high oxy level, low CO2

hyperventilation

Carbon Dioxide

produced continously in tiss by product of metabolism

Breathing Patterns

measured in breaths per min (even + unlabored

Adults: 12 - 40

Children: 20 - 40

Infants more than 40 (can go to 60)

room ventilation (humidity + temp) can affect breathing

Located in the brain stem + their roles

Medulla - sets breathing patterns

• from medulla, motor nerve fibers extend into spinal cord (cervical)

• from there ner fibers extend through phrenic nerve to diaphragm

Pons - modifies pattern

Diaphragm + resp mus are voluntary, can be reg consciously by messages from higher brain centers (cerebral context)

hyperpnea

abnormal high in depth + rate of respiration

Hypopnea

low rate + depth of breathing

tachypnea

exessive rate of breathing (norm during exercise)

apnea

temporary pause of breathing that lasts at least 10 seconds

Chemoreceptors

sensitive to chemicals dissolved in fluids (important for control of resp)

Central chemoreceptors

• located near medullary resp center in brainstem respond to raises CO2 levels

• CO2 has most immediate effect in regulating resp @ central chemoreceptors

Hypercapnia

raised CO2 levels

Peripheral chemoreceptors

located in carorid + aortic bodies (in neck + aortic arch)

respond mainly to oxy level considerably below norm

Hyperventilation

rapid + deep resp that allows increased am of air to enter alveoli

high oxy level + low CO2 level (hypocapnia)

increases blood pH ALKALOSIS

Hypoventilation

insufficient am of air in alveoli

decreases blood pH

causes high CO2 concentration, low blood pH ACIDOSIS

Orthopnea

difficulty breathing relieved by sitting upright on pillows or in chair

Kussmaul

resp deep rapid resp seen in uncontrolled diabetic (metabolic acidosis) form of hyperventilation

Hypoxia

lower than norm oxy levels in tiss

Hypoxemia

lower than norm oxy concentration in arterial blood

suffocation

cessestion of resp, a blockage of resp passages

Cheyne-Stokes

resp rhymic variation in depth of resp mvt alternating w/ period os apnea, can last 30 secs to 2 mins

caused by depression of breathing centers (seen in critically ill pts)

Croup

affects children under 3 (barking cough)

Influenza

acute contagious viral disease of UPPER RES TRACT

Tuberculosis (TB)

invade any body tiss, in lung, contagious cough

Pneumonia

lung inflammation where fluid fills air spaces

Pharyngitis

sore throat

Upper resp infection

throat + up

RSV

most common cause of LOWER RES TRACT infection

Asthma

reversible changes that cause inflammation of airway

Chronic Obstructive Pulmonary Disease (COPD)

both chronic bronchitis + emphysema

norm air flow obsturcted causing SOB + dyspnea

reduces oxy + CO2 exchange

can’t take too much oxy

Pneumonia

infection in the air sacs that causes inflammation + fluid build up in lung or both

Lobar Pn - entire section of lobe is infected

Bronchopneumonia - scattered throughout the lung

Hay fever

hypersensitivity to allergens

Seasonal or chronic

if allergen is present year round

Sudden Infant Death Syndrome (SIDS)

“crib death”

unexplained death, no known cause, under 1 year old

possible maternal conditions during pregnancy (smoking, 20 + under, low weight gain, anemia, illegal drug use)

Chronic Bronchitis

causes chronic inflammation of airway linings, excessive products of secretions (sputum)

Acute Respiratory Distress Syndrome (ARDS)

sudden reversible inflammatory lung conditiong

sepsis, allergy, lung trauma

Emphysema

air trapping + over-inflation (dilation) of alveoli + alveolar destruction

Surfactant Deficiency disorder

respiratory distress syndrome

surfactant produced by specialized fetal lung cells starting at 26 weeks

Pleurisy

inflammation of pleura usually accompanies lung infection (pneumonia or TB)

Pneumothorax

air in pleural space that can cause lung to collapse

Lung cancer

most common cause of death; most likely comes from smoking but someone with lung cancer does not mean they smoked

suction apparatus

used for removing mucus or other substances from resp tract by neg pressure

Amboo bag

artificial resp apparatuses (used during CPR)

Hemothorax

blood in the pleural space sometimes caused by penetrating chest wounds (1st priority to stop bleeding)

Tracheostomy tube

used if pharynx or larynx is obstructed + involves insertions of small tube in trachea to act as an artificial airway

Bronchoscope

fiber optic tube used for inspection of primary + larger bronchial tubes

Bronchoscopy

can be done to examine air passages + passages to remove foreign bodies

Affects of aging on the Resp Tract

tiss lose elasticity, increased susceptibility to infection, regular aerobic activity