ch. 22 & 23 unit objectives

Diaphragm

Prime mover of respiration; contraction flattens diaphragm, enlarging thoracic cavity, pulling air into lungs.

External Intercostals

Muscles that stiffen thoracic cage, prevent inward collapse during inspiration, contributing about 1/3 of air inhaled.

Scalenes

Muscles that fix or elevate ribs 1 and 2, assisting in inspiration.

Erector spinae, pectoralis major and minor, serratus anterior that increase thoracic volume during forced inhalation.

Accessory Muscles in Forced Respiration

Abdominal Muscles in Forced Expiration

Increase abdominal pressure by pushing viscera against diaphragm, aiding in forced expiration.

Brainstem Centers for Breathing

Ventral respiratory group generates rhythm, dorsal respiratory group modifies rate and depth, pontine respiratory group adapts breathing to activities.

Boyle's Law

At constant temperature, gas pressure is inversely proportional to volume; increase in lung volume causes air to flow in.

Inhalation Process

Thoracic cavity expands, lung volume increases, intrapulmonary pressure drops below atmospheric pressure, allowing air to flow in.

Exhalation Process

Thoracic cavity contracts, lung volume decreases, intrapulmonary pressure rises above atmospheric pressure, causing air to flow out.

Bronchodilation Causes

Sympathetic stimulation and epinephrine increase bronchiole diameter, reducing resistance and increasing airflow.

Bronchoconstriction Causes

Parasympathetic nerves, histamine, cold air, irritants decrease bronchiole diameter, increasing resistance and reducing airflow.

Pulmonary Compliance

Ease of lung expansion, influenced by elasticity of lung tissue and surface tension in alveoli.

Surface Tension in Alveoli

Surfactant reduces surface tension, prevents collapse, and maintains airflow in alveoli.

Anatomical Dead Space

Air in the conducting zone that doesn't participate in gas exchange, approximately 150 mL.

Alveolar Ventilation Rate (AVR) Calculation

AVR = (Tidal volume - Dead space) × Respiratory rate.

Tidal Volume (TV)

Volume of air inhaled and exhaled in one breathing cycle, approximately 500 mL.

Inspiratory Reserve Volume (IRV)

Additional air inhaled with maximum effort, approximately 3,000 mL.

Expiratory Reserve Volume (ERV)

Additional air exhaled with maximum effort, approximately 1,200 mL.

Residual Volume (RV)

Air remaining in lungs after maximum expiration, approximately 1,300 mL.

Vital Capacity (VC) Calculation

Max air exhaled after max inhalation: VC = TV + IRV + ERV, approximately 4,700 mL.

Inspiratory Capacity (IC) Calculation

Max air inhaled after tidal expiration: IC = TV + IRV, approximately 3,500 mL.

Functional Residual Capacity (FRC) Calculation

Air remaining in lungs after tidal expiration: FRC = RV + ERV, approximately 2,500 mL.

Total Lung Capacity (TLC) Calculation

Max air lungs can hold: TLC = RV + VC, approximately 6,000 mL.

primary bronchus (1°)

feeds air to 1 lung

secondary bronchus (2°)

feeds air to 1 lung lobe

tertiary bronchus (3°)

feeds air to 1 lung segment

cardiac notch

why is there only 2 lobes on the left lung

c-shaped rings

is the primary bronchi supported by cartilage plates or hyaline cartilage c-shaped rings

cartilage plates

is the secondary bronchi supported by cartilage plates or hyaline cartilage c-shaped rings

cartilage plates

is the tertiary bronchi supported by cartilage plates or hyaline cartilage c-shaped rings

bronchopulmonary segment

functionally independent unit of the lung tissue that allows for parts of the lung to be removed and still maintain ability to function

true

true or false smaller space is better for gas diffusion

conduction zone

movement of air

respiratory zone

the exchange of gas

squamous alveolar cells (stationary), great alveolar cells (stationary), alveolar macrophages (wandering)

name the cells of the alveolus and which are stationary and wandering

respiratory cycle

one complete inspiration and expiration

yes

does an increased surface area = increased gas exchange

spirometer

what measures the force of exhale

partial pressure

concentration of gas not liquids

Hb + H^+ = releasing O2

chloride shift during the systemic gas exchange

Hb - H^+ = bind O2

CO2 unloading during alveolar gas exchange

7.35 - 7.45

arterial blood level of pH

40 mm Hg

arterial blood level of PCO2

95 mm Hg

arterial blood level of PO2

pH

the most potent stimulus for breathing

acidosis

blood pH lower than 7.35

alkalosis

blood pH higher than 7.45

hypocapnia

PCO2 less than 37 mm Hg

most common cause of alkalosis

hypercapnia

PCO2 greater than 43 mm Hg

most common cause of acidosis

ischemic hypoxia

inadequate circulation of blood

anemia hypoxia

due to anemia resulting from inability of blood to carry enough oxygen

histotoxic hypoxia

metabolic poisons such as cyanide prevent tissues from using oxygen

cyanosis

blueness of skin (sign of hypoxia)

small cell carcinoma

most dangerous lung cancer

gas exchange

communication

olfaction

acid-base balance

what are the functions of the respiratory system

acid-base balance

what function of the respiratory system influences pH of body fluids by eliminating CO2

olfaction

what function of the respiratory system is the sense of smell

communication

what function of the respiratory system is speech and other vocalizations

gas exchange

what function of the respiratory system is O2 and CO2 exchanged between blood and air

nose, pharynx, larynx, trachea, bronchi, lungs

organs of the respiratory system

respiratory zone

consists of alveoli and other gas exchange regions

upper respiratory tract

nose through larynx

lower respiratory tract

trachea through lungs

warms, cleanses, and humidifies inhaled air

detects odors

serves as resonating chamber that amplifies voice

functions of the nose

breathing in

moistens air

cleans air

heats air

breathing out

removes moisture and heat

olfactory epithelium

detects odors

nasopharynx

oropharaynx

laryngopharynx

what are the three regions of the pharynx

nasopharynx

passes only air and is lined with pseudo stratified columnar epithelium

oropharynx and laryngopharynx

pass air, food, and drink and lined with stratified squamous epithelium

larynx

voice box

epiglottis

flap that covers the opening of the larynx

thyroid cartilage

known as the adam’s apple

arytenoid cartilages

corniculate cartilages

cuneiform cartilages

cartilages of the larynx

thyrohyoid ligament

circotracheal ligament

ligaments of the larynx

trachea

known as the windpipe

pseudostratified columnar epithelium

what type of epithelium is the trachea lined with

mucociliary escalator

mechanism used for debris removal

mucus traps inhaled particles

upward beating cilia drives mucus toward pharynx where it is swallowed

VRG (ventral respiratory group)

primary generator of the respiratory rhythm

ventral respiratory group

VRG

DRG (dorsal respiratory group)

modifies rate and depth of breathing

dorsal respiratory group

DRG

PRG (pontine respiratory group)

adapts breathing to certain situations such as sleep, exercise, emotional responses, etc.

pontine respiratory group

PRG

true

true or false: during hyperventilation CO2 levels drop as pH rises

anatomic dead zone

conducting zone of airway where there is no gas exchange

tidal volume (TV)

volume of air inhaled and exhaled in one cycle of breathing (normal breathing)

inspiratory reserve volume (IRV)

air in excess of tidal volume that can be inhaled with maximum effort

expiratory reserve volume (ERV)

air in excess of tidal volume that can be exhaled with maximum effort

residual volume (RV)

air remaining in lungs after maximum expiration

vital capacity (VC)

total amount of air that can be inhaled and exhaled with maximum effort

=ERV + TV + IRV

inspiratory capacity (IC)

maximum amount of air that can be inhaled

= TV + IRV

functional residual capacity (FRC)

amount of air remaining in lungs after normal normal tidal expiration

= RV + ERV

total lung capacity

maximum amount of air the lungs can contain

= RV + VC