Lab 7 - Respiratory Air Flow and Volume

primary function of the respiratory system

release carbon dioxide from the body and acquire oxygen for use by the body (accomplished through respiration)

4 steps of respiration

pulmonary ventilation, external respiration, transport of respiratory gases and internal respiration

pulmonary ventilation

movement or air into the lungs (inspiration) and out of the lungs (expiration) in order to facilitate gas exchange.

external respiration

carbon dioxide diffuses to the lungs from the blood, oxygen diffuses to the blood from the lungs

transport of respiratory gases

carbon dioxide is transported from the cells of body tissues to the lungs, oxygen is transported from the lungs to the cell of body tissues (through blood of cardiovascular system)

internal respiration

oxygen diffuses from blood to the cells of the body, carbon dioxide diffuses from the cells of the body to the blood

carbon dioxide is produced and oxygen is used by cells for energy production during cellular respiration (in oxidative reactions)

structures of upper respiratory system

nose to the larynx

structures of lower respiratory system

larynx and structures inferior

nose

warms and moistens entering air, provides a resonating chamber for vocalizations, cleans & filters entering air, houses the olfactory receptors

olfactory mucosa epithelium

lines superior nasal cavity and has receptors for smell

respiratory mucosa

lines rest of nose, composed of pseudostratified ciliated columnar epithelium with goblet cells and seromucous nasal glands

secrete antibiotic defensins (assist killing microbial invaders)

seromucous nasal glands

composed of cells that secrete mucus (traps bacteria, dust, and debris) & cells that secrete watery enzyme rich fluid (humidify, lysozyme = antibacterial)

sneeze reflex

triggered when irritants (dust, pollen) contact the rich supply of sensory nerve endings in the nasal cavity, leading to a forceful expulsion of air from the lungs to clear the irritants.

nasal conchae

increase surface area and help create turbulence, deflects non-gaseous particles onto the mucous coatings

paransal sinuses

located in frontal, sphenoid, maxillary, and ethmoid bones that lighten the skull, improve voice resonance, and produce mucus that drains into the nasal cavity.

swallowing food

muscular soft palate and uvula move superiorly to block off nasopharynx, and the epiglottis flaps over the larynx, to keep food out of the nasal cavity and lungs

in nasopharynx, cilia propel mucus toward the stomach

pharyngeal tonsil (adenoid) of the nasopharynx

contains lymphatic tissue that traps and destroys pathogens

when swollen can block the airway and cause breathing difficulties.

pharyngotympanic tubes

connect the middle ear to the nasopharynx, helping to equalize pressure in the ear.

oropharynx and laryngopharynx

receive both food and air, contain a more protective stratified squamous epithelium

zones of respiratory system

respiratory zone and conducting zone

respiratory zone

site of external respiration (where gas is exchanged), is made up of the microscopic alveoli (main site of exchange), alveolar ducts, and respiratory bronchioles

conducting zone

consists of all tubes transporting air from the nose to the respiratory bronchioles, air is humidified, warmed, and filtered/ cleansed

larynx

houses vocal folds (vocal cords) for voice production

laryngeal prominence

the visible bump on the thyroid cartilage, commonly known as the Adam's apple, that is more prominent in males.

arytenoid cartilages

anchor vocal folds

glottis

vocal folds and opening between them (air passes through and produces sound when the vocal folds are positioned strategically)

opens and closes during intermittent expiration to produce speech

laryngeal muscles

move the cartilages of the larynx (mostly the arytenoid) to change the length of the vocal folds and size of the glottis to change the pitch and produce vibrations

laryngitis

an inflammation of the vocal folds causing them the swell and vibrate incorrectly

Valsalva maneuver

if vocal folds are completely closed over the glottis to stop air passage, abdominal muscles contract, and the glottis closes to increase the intra-abdominal pressure to help empty the rectum

boyle’s law

at a constant temperature, the pressure of a gas varies inversely with its volume

forced deep expiration

contracting abdominal wall muscles which pushes the abdominal organs somewhat superiorly against the thorax, and the rib cage is pulled inferiorly to further increase pressure in the thorax & internal intercostal muscles depress the rib cage to further increase pressure for forced expiration

trachea

composed of a mucosa (with pseudostratified columnar ciliated epithelium containing goblet cells which produces and moves mucus up out of lungs), submucosa (seromucous glands), adventitia (outermost connective tissue sheath)

trachealis muscle

lies between the esophagus and trachea, contraction aids in the rapid movement of air and mucus out of the lungs and trachea during coughing

lobe of lungs

3 on the right, 2 on the left

alveolar sac

cluster of alveoli coming off the alveolar duct

walls of alveoli

single thin layer of squamous epithelial cells (type I alveolar cells)

alveoli

densely covered with pulmonary capillaries

respiratory membrane

created by capillary and alveolar walls with their fused basement membranes sandwiched

ventilation-perfusion coupling

air that is high in oxygen and low in carbon dioxide is constantly being refreshed into the alveoli

locally autoregulated in the lung

ventilation

amount of gas reaching the alveoli

perfusion

blood flow in the pulmonary capillaries

cubodial type II alveolar cell

secrete antimicrobial proteins and surfactant that coats the alveoli

pulmonary surfactant

decreases the surface tension in the alveoli

fine elastic fibers

surround entire bronchial tree, including the alveoli and help maintain their structure, allowing for elastic recoil during breathing.

macrophages from the alveoli

keep us healthy by destroying pathogens are swept to the pharynx by cilia for disposal once they become too aged to function

mediastinum

heart, great vessels, esophagus, bronchi, and other organs

pleural fluid

fills space between the two pleural membranes

allows the lungs to easily move as we breathe

pleurisy

inflammation of the pleura

if persistently untreated can lead to fluid build-up in the pleural space, puts pressure on the lungs and decreases the ability to breathe

pneumonia

inflammation primarily of the alveoli in the lungs, often caused by infection or irritants.

can cause atelectasis when bronchioles become clogged with infectious materials and fluid accumulation in the alveoli, leading to difficulty breathing and reduced oxygen exchange.

cardiac notch

left lung is molded to accomodate the heart

tertiary bronchi

serve each bronchopulmonary segment (along with an independent artery and vein)

lung compliance

“stretchiness” of the lungs

the more a lung expands the greater its compliance and the higher the compliance the more easy it is for the lung to expand

visceral sensory nerve fibers and motor innervation in lungs

parasympathetic nerves = stimulate air tubes to constrict

sympathetic nerves = stimulate air tubes to dilate

renin angiotensin aldosterone pathway

helps regulate blood pressure

1. blow flow to the kidneys decreases, juxtaglomerucular cells secrete renin to the systemic circulation

2. renin converts angiotensinogen (from the liver) to angiotensin I

3. in the lungs, angiotensin converting enzyme (ACE) , catalyzes the conversion of angiotensin I to angiotensin II

4. angiotensin II stimulates arterioles to constrict & stimulates the secretion of aldosterone from the zone of glomerulosa of the adrenal cortex

5. increases reabsorption of sodium in the kidney

6. increase blood pressure to increase blood flow to the glomeruli of the kidneys

intrapulmonary pressure

pressure in the alveoli

changes as we breathe to move gases between the lungs and blood between the lungs and the atmosphere

intrapleural pressure

pressure in the pleural space or cavity

always slightly less than intrapulmonary pressure to prevent lung collapse and assist in lung expansion during breathing.

transpulmonary pressure

difference between the intrapulmonary and intrapleural pressures

atelectasis

lungs collapse due to lose of small transpulmonary pressure difference

non-respiratory air movements

hiccups or sneezing

Flow (F)

Flow = change in Volume/ change in time

volume of gas

expands with warming, therefore, the air volume expired from the lungs will be slightly greater than that inspired

tidal volume (TV or VT)

specific volume of air is drawn into and then expired from the lungs

expired minute volume (MV or VE)

the total volume of air expired from the lungs in one minute, calculated as tidal volume multiplied by the respiratory rate.

residual volume (RV)

volume of air remaining in the lungs after a full expiration

cannot be measured by spirometry because unable to exhale in the lungs

prevents lung collapse and helps keep the alveoli open

Spirometry

measured by pneumotachometer

pulmonary ventilation

keeps new air consistently and frequently entering the alveoli so that the pressure of oxygen in the alveoli is kept higher, and the carbon dioxide lower, than the oxygen deficient, carbon dioxide loaded, blood perfusing the pulmonary capillaries surrounding the alveoli

Dalton’s Law of partial pressures

the total pressure exerted by a mixture of gases will equal the sum of the partial pressures exerted independently by each of the gases in the mixture

the partial pressure exerted by each gas will be directly proportional to the percentage of that gas in the mixture

Henrys Law

when a gas is in contact with a liquid, the gas will dissolve into the liquid in proportion to its partial pressure

the larger the concentration of this independent gas in the mixture of gases in the gas phase, the greater and more rapidly that independent gas will go into solution in the liquid

Inspiratory capacity formula

IC = TV + IRV

Expiratory Capacity formula

EC = TV + ERV

Vital Capacity formula

VC = IRV + ERV +TV

Functional residual capacity formula

FRC = ERV + RV

Total Lung Capacity formula

TLC = VC + RV

Tidal Volume (TV or VT)

avg female = 500ml

avg male = 500 ml

Amount of air expelled with each normal resting breath

Inspiratory Reserve Volume (IRV)

avg female = 1900ml

avg male = 3100 ml

amount of air that can be forcefully inhaled after a normal tidal inspiration

Expiratory Reserve Volume (ERV)

avg female = 700ml

avg male = 1200ml

amount of air that can be forcefully exhaled after a normal tidal expiration

Residual Volume (RV)

avg female = 1100ml

avg male = 1200ml

amount of air remaining in the lungs after a maximum forced expiration

Total Lung Capacity (TLC)

avg female = 4200ml

avg male = 6000ml

maximum amount of air contained in the lungs after a maximum inspiration

Vital Capacity (VC)

avg female =3100ml

avg male = 4800ml

maximum amount of air that can be expired after a maximum inspiration

Inspiratory Capacity (IC)

avg female =2400ml

avg male = 3600ml

maximum amount of air that can be inspired after a normal tidal expiration

Expiratory Capacity (EC)

avg female = 1200ml

avg male = 1700ml

maximum amount of air that can be expired after a normal tidal inspiration

Functional (forced) residual capacity (FRC)

avg female = 1800ml

avg male = 2400ml

volume of air remaining in the lungs after a normal tidal expiration

hyperbaric oxygen chambers

contain oxygen at partial pressures higher than what we are normally exposed to in the atmosphere

used to drive oxygen into the blood for carbon monoxide poisoning or sometimes gangrene

excess oxygen

can lead to oxygen toxicity, causing damage to lungs and central nervous system.

hemoglobin

a protein in red blood cells that binds to oxygen for transport throughout the body.

affinity

how easily oxygen binds to hemoglobin

Bohr Effect

increasing partial pressures of carbon dioxide weakening the hemoglobin-oxygen bond

chloride shift

bicarbonate exits the red blood cells in exchange for chloride ions, helping to maintain ionic balance during carbon dioxide transport.

Haldane effect

decrease in hemoglobin's affinity for oxygen as CO2 levels rise, enhancing CO2 transport.

hypoxia

inadequate oxygen delivery to the body tissues

classified based on cause

anemic hypoxia

caused by a reduction in hemoglobin levels or impaired hemoglobin function, leading to decreased oxygen-carrying capacity of the blood.

ischemic hypoxia

caused by inadequate blood flow to tissues, resulting in insufficient oxygen delivery to those areas.

histotoxic hypoxia

caused by toxins that inhibit cellular respiration, preventing tissues from utilizing oxygen effectively.

hypoxemic hypoxia

caused by low partial pressure of oxygen in the blood, often due to high altitudes or respiratory diseases, leading to inadequate oxygenation of tissues.

carbon monoxide posioning

a type of hypoxemic hypoxia that occurs when carbon monoxide binds to hemoglobin in the blood, reducing its ability to carry oxygen to the body's tissues.

caused by breathing in smoke or fumes

ventral respiratory group (VRG)

medullary respiratory center of the medulla oblongata

that controls the basic rhythm of breathing by stimulating the diaphragm and intercostal muscles.

dorsal respiratory group (DRG)

medullary respiratory center of the medulla oblongata

that integrates sensory information to modify the rhythm of breathing, particularly during active respiration.

eupnea

clinical term for normal breathing rate

15 breaths per minute

pontine respiratory center

regulates the transition between inhalation and exhalation, smoothing the breathing pattern.

hypercapnia

clinical term for high carbon dioxide levels in the blood