Chapter 22: The Respiratory System

A series of flashcards covering key terms and concepts from Chapter 22 on the Respiratory System.

Respiratory system

An organ system that takes in air and expels it from the body.

Breathing

Represents life, consisting of inhaling oxygen and exhaling carbon dioxide.

ATP

Adenosine triphosphate, the energy currency of the cell, requiring oxygen for synthesis.

Gas exchange

The process of oxygen (O2) and carbon dioxide (CO2) exchanged between blood and air.

Cardiopulmonary system

The combined functions of the respiratory and cardiovascular systems to deliver oxygen and remove carbon dioxide.

Acid-Base balance

The regulation of pH in body fluids by eliminating CO2.

Conduction division

Part of the respiratory system consisting of passages only for airflow, with no gas exchange.

Alveoli

Microscopic air pouches in the lung, where gas exchange occurs.

Pharynx

Muscular funnel extending from nasal apertures to larynx, divided into nasopharynx, oropharynx, and laryngopharynx.

Larynx

Voice box that aids in sound production and prevents food from entering the airways.

Trachea

Windpipe that is a rigid tube supported by cartilaginous rings, conducting air to the bronchi.

Pulmonary ventilation

One cycle of inspiration (inhaling) and expiration (exhaling).

Diaphragm

The primary mover of respiration, contracting to enlarge the thoracic cavity.

Hypoxia

A deficiency of oxygen in a tissue, often marked by cyanosis.

Chronic obstructive pulmonary diseases (COPDs)

Long-term obstruction of airflow and reduction in pulmonary ventilation, mainly including chronic bronchitis and emphysema.

Smoking

The major cause of lung cancer, which contains over 60 carcinogens.

Major functions of respiration

gas exchange, communication, olfaction, acid-base balance, blood pressure regulation

blood pressure regulation

assists with synthesis of angiotensin II, hormone that regulates BP

conduction division

consist of the passages that serve only for airflow, nostrils through major bronchioles

respiratory division

consists of the alveoli and other gas-exchange regions

URT

nose through larynx

LRT

trachea through lungs

Nose functions

warms, cleanses, humidifies air; dectects odor

nasal cavity

extends from the nostrils or anterior/external nares to the posterior opening called the choanae

nasal septum

comer and perpendicular plate of the ethmoid

superior, middle, and inferior nasal conchae

3 folds of tissue on lateral walls

meatuses

narrow air passage beneath each conchae; narrowness and turbulence ensures air contacts mucous membranes

nasal mucosa

psuedostratified ciliated columnar epithelium; secretes mucous that traps particles; bacteria destroyed by lysosomes in the mucous; sweep debris-laden mucus into pharynx to be swallowed

olfactory epithelim

detects odors

pharynx

muscular funnel extending about 5 in. from posterior nasal apertures to larynx

Three regions of pharynx

nasopharynx, oropharynx, laryngopharynx

Nasopharynx (pseudostratified columnar epithelium)

recieves auditory tubes and contains pharyngeal tonsil; 90 degree downward turn traps large particles

oropharynx (stratified squamous epithelium)

contains palatine tonsils

laryngopharynx (stratified squamous epithelium)

esophagus begins at that point

larynx (voice box)

cartilaginous chamber about 4 cm long

Larynx functions

keep food and drink out of airways; sound production

glottis

vocal cords and superior opening

epiglottis

directs food and drink to esophagus; vertical at rest; during swallowing extrinsic muscles of larynx pull larynx upwards; tongue pushes epiglottis down to meet it; closes airway

Larynx cartilage amount

9

Walls of larynx

interior wall has 2 folds on each side, from thyroid cartilage in front to arytenoid cartilages in back

vestibular folds

dont play a role in speech but close larynx when swallowing

vocal cords

produces sound when air passes between them

intrinic muscles

rotate corniculate and arytenoid cartilages; operates vocal cords

extrinsic muscles

connect larynx to hyoid bone; pulls larynx upward during swallowing

Trachea (windpipe)

rigid tube anterior to esophagus; supported by 16-20 c shaped cartliginous rings (hyaline)

Hyaline

openings in rings face posterior towards esophagus

trachealis muscle

spans opening in rings, adjust airflow by expanding or contracting

Inner lining of trachea

ciliated pseudostratified epithelium which functions as mucociliary escalator

tracheostomy

to make a temporary opening in the trachea and insert a tube to allow airflow; prevents asphyxiation; inhaled air bypasses nasal cavity and is not humidified; can dry out mucous membranes; promotes infection due to interference with clearance

intubation

when a patient is on a ventilator, air is introduced directly into trachea; air must be filtered and humidified

Primary bronchi

arise from trachea; 2-3 cm enter hilum of lungs; right bronchus slightly wider and more vertical; aspirated foreign objects lodge in the right main bronchus more often than in the left

secondary (lobar) bronchi

one secondary bronchus for each lobe of lung; right has 3 left has 3 2

tertiary (segmental) bronchi

10 right, 8 left; bronchopulmonary segment: portion of lung supplied by each

bronchioles (lack cartilage)

layer of smooth muscle to allow dilation and contraction; divides into 50-80 terminal bronchioles; ciliated- end of conducting division

respiratory bronchioles

divide into 2-10 alveolar ducts; end in alveolar sacs

alveoli

microscopic air pouches in the lung, each about 0.2 to 0.5 mm in diameter; main site for gas exchange

(Type I) squamous alveolar cells

most common; allow for gas exchange betweenn the capillaries from the pulmonary artery and the alveoli

(Type 2) alveolar cells (great alveolar cells)

secrete a lipoprotien surfactant; few ammount

alveolar macrophages (dust cells)

defend against dust particles

right lung

shorter than left because liver rises higher on the right; has 3 lobes

left lung

tall and narrow because the heart tilts toward the left and occupies more space on this side of the mediastinum; has indentation called cardiac impression; two lobes separated by oblique fissure

pleura

serous membrane that line thoracic wall and forms surface of ling

visceral pleura

on lungs

parietal pleura

lines rib cage

pleural cavity

located between visceral and parietal pleura

pleural fluid

found within the pleural cavity

functions of pleurae and pleural fluid

reduce friction; create pressure gradient (assist lung inflation); compartmentalization (prevents spread of infection)

Pulmonary ventilation

respiratory cycle (one complete breath), quiet respiration (while at rest, automatic), forced respiration (deep, rapid)

Diaphragm

primary mover of respiration; contraction flattens diaphragm, enlarging thoracic cavity and pulling air into lungs

scalenes

hold first pair of ribs stationary

external and internal intercostals

stiffen thoracic cage; increases diameter

pectoralis minor, stercleidomastoid and erector spinae muscles

used in forced inspiration

abdominals and lats

forced expiration (sing, cough, sneeze)

Unconcious breathing

controlled by neurons in medulla oblongata and pons

voluntary control of breathing

provided by motor cortex of frontal lobe

inspiratory neurons

fire during inspiration

expiratory neurons

fire during forced expiration

phrenic nerve

fibers of this go to diaphragm; intercostal nerves to intercostal muscles

Medulla

inspiratory center (dorsal respiratory group); expiratory center (ventral respiratory group)

pons

pneumotaxic center; apneustic center

bronchitis

inflammation of bronchial walls; causes constriction and breathing difficulty

asthma

excessive stimulation and bronchoconstriction; stimulation severely restricts airflow

Respiratory distress syndrome

difficult respiration due to alveolar collapse; caused when type II alveolar cells don’t produce enough surfactant; pre-mature infants primarily

pneumonia

inflamation of lobules; causes fluid to leak into alveoli; compromises function of respiratory membrane

pulmonary embolism

easily blocked by blood clots, fats, or air bubbles

Atmospheric (barometric) pressure

weight of air above (1 ATM=760 mmHg); drives respiration

Intrapulmonary pressure

air pressue within lungs; changes with lung volume according to Boyle’s law; increased volume=decreased pressure

air flows into lungs

when you lower intrapulmonary pressure below the atmospheric pressure (inhaling= increase volume= decrease pressure)

Bronchoconstriction

decreased diameter of a bronchus or bronchiole; triggered by airborne irritants, cold air, parasympathetic stimulation, histamine, asthma; decreases airflow

Bronchodilation

increase in diameter of a bronchus or bronchiole; sympathetic nerves, epinephrine; increased airflow

Alveloar surface tension

thin film of water needed for gas exchange that creates surface tension that acts to collapse alveoli and distal bronchioles

Pulmonary surfactant (great alveolar cells)

decreases surface tension

Alveolar ventilation

only air that enters alveoli is available for gas exchange and not all inhaled air gets there

anatomical dead space

conducting division of airway where there is no gas exchange

Physiologic (total) dead space

pulmonary disease, some alveoli may be unable to exchange gases; the sum of anatomic dead space and pathological alveolar dead space

Spirometer

menters ventilation

tidal volume

volume of air inhaled and exhaled in cycle of breathing

inspiratory reserve volume

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

expiratory reserve volume

air in excess of tidal expiration that can be exhaled with max effort

residual volume (keeps alveoli inflated)

air remaining in lungs after maximum expiration; the amount that can never voluntarily be exhaled