physiology respiratory system

two major areas in the respiratory system

conducting zone and respiratory zone

what is conducting zone

everything that is moving air in and out of pathway before gas exchange (nose, trachea, pharynx, lungs, etc)

what is respiratory zone

everything that is conducting gas exchange (bronchioles and alveoli)

functions of respiratory system

gas exchange, communication, olfaction, acid-base balance, blood pressure regulation, blood and lymph flow, blood filtration, expulsion of abdominal contents

how does the respiratory system regulate blood pressure

angiotensin II

how does the respiratory system regulate blood filtration

by dissolving small clots

how does the respiratory system expel abdominal contents

deep breath and push mechanisms

terminal bronchioles

responsible for the air going out

respiratory bronchioles

alveoli, gas exchange

upper respiratory tract

nose to the trachea

nose functions

olfaction, warming cleaning and humidification of air, voice amplification through resonating chamber

features of nostrils

conchae and nasopharynx

nasal cavity anatomy

divided into left and right halves via nasal septum, starts at vestibule (with guard hairs or vibrissae)

olfactory epithelium

part of nose on superior nasal conchae

respiratory membrane

pseudostratified ciliated columnar with goblet cells

lamina propria (basement membrane)

mucus glands

what pushes mucus to pharynx

beating of cilia on epithelial surface (ciliary action)

what happens if one side of the nose is clogged for days

stratified squamous epithelium

pharynx

muscular funnel

inferior concha lamina propria has

erectile tissue that engorges every 30 to 60 mins to keep cells moist

nasopharynx

above soft palate and receives the auditory tube (Eustachian)

oropharynx

soft palate to epiglottis

laryngopharynx

posterior to larynx, epiglottis to esophagus

larynx

cartilaginous chamber to keep food and drink out of trachea, superior opening guarded by epiglottis

swallowing mechanism larynx

at rest, is open. when swallowing, muscles pull this structure up and tongue pushes epiglottis down

laryngeal prominence

found on the thyroid cartilage and stimulated by testosterone (adams apple)

interior wall of larynx has

two folds (superior and inferior)

superior vestibular folds

no role in speech, close larynx when swallowing

inferior vocal folds

cords that produce sound when air passes, help with pitch

trachea

“windpipe”, supported by rinds of hyaline, lined with pseudostratified columnar epithelium and goblet cells (cilia beating = mucus travels)

lower respiratory system

lungs, bronchial tree

lungs

hilum of lung accepts main bronchus, left lung has cardiac notch and 2 lobes while right lung has 3 lobes

bronchial tree

consists of primary, secondary (lobar), and tertiary (segmental) bronchi

alveoli

alveolus walls contain squamous (type I) and great (type II) cells

type II cells

round-cuboidal cells that repair alveolar cells and secrete surfactant

alveolar macrophages

dust cells that phagocytize dust particles

what happens when there is fluid in the lungs

gases diffuse too slowly through liquids, capillaries absorb excess liquid, loss of lymphatic capillaries

what do lymphatic capillaries look like

minnow trap

pleurae function

reduce friction, create pressure gradient, compartmentalize

pleurae types

visceral and parietal

pulmonary ventilation

breathing: inspiration and expiration. forms a partial vacuum to make space for air

quiet breathing

expiration, do not use muscles, passive process

active breathing

forced respiration (deep and/or rapid), use abdominals and internal intercostals

muscles of inspiration

accessory (sternocleidomastoid and scalene group) and principal muscles (external intercostals and diaphragm)

muscles of expiration

quiet breathing (passive activity from lungs, rib cage, diaphragm) and active breathing (internal intercostals, abdominals)

neural control of breathing

rhythmic

why is breathing rhythmic

respiratory system consists of skeletal muscle and multiple muscles, which are somatic

brainstem respiratory centers

3 centers in reticular formations of medulla and pons: ventral, dorsal, pontine

central chemoreceptors

pH of cerebrospinal fluid

peripheral chemoreceptors

aorta: carotid and aortic bodies respond to O2 and CO2, pH

stretch receptors

lungs: smooth muscle of bronchi and visceral pleura. excessive inflation triggers inflation (hering-breuer) reflex.

irritant receptors

lungs: nerve ending that responds to smoke, dust, pollen, cold air, mucus, etc causing coughing, shallow breathing, apnea, etc.

odine’s curse

taking away autonomic breathing functions, such as polio or neurosurgery accidents that require ventilators for sleep

voluntary breathing

important in speaking, singing, breath holding. control originates in cerebral cortex

what is between visceral and parietal pleurae

fluid to help reduce friction of lungs expanding into one another

fluid between pleurae

is 2 mmHg above atmosphere which helps allow the lungs to inflate

pneumothorax

where lungs collapse due to lack of pressure (lack of fluid at atmosphere)