Respiratory system general
a group of passages that filter air and transport it to lungs
Passage of air through respiratory system
oral/nasal cavities-> pharynx-> larynx-> trachea-> primary bronchi-> secondary bronchi-> tertiary bronchi-> bronchioles-> terminal bronchioles-> resiratory bronchioles-> alveoli
Functions of respiratory system
gas exchange; move air; protect respiratory surfaces; defense; produce sounds; blood pH regulation
Entrance of air into the respiratory system
air enters through external nares which are protected by hairs that prevent large particles from entering lungs
Interior division of nose
vestibule divided by nasal septum
Where are olfactory receptors found?
on superior surface of nasal cavity
Other than olfactory receptors, what is the nasal cavity lined with?
respiratory mucosa
Functions of respiratory mucosa
moisten air to prevent dehydration of lungs and trap incoming foreign particles with help of hair
Conchae
bony projections found on the lateral walls of nasal cavity
Function of conchae
divide cavity into passages; support mucous membranes; increase surface area; increase turbulence, which moistens and warms air
Separation of nasal cavity from oral cavity
palates
Position of hard palate
anterior/superior surface of mouth
Position of soft palate
posterior/superior surface of mouth
Sinuses
air-filled sacs located in several bones of the skull; open into nasal cavity; lined with mucous membranes
Functions of sinuses
decrease weight of skull; provide resonant chambers
Resonant chambers
give quality of voice
Pharynx
(throat); shared passageway for respiratory and digestive system
Areas of pharynx
nasopharynx; oropharynx; laryngopharynx
Placement of nasopharynx
above uvula and posterior to lateral nares
Placement of oropharynx
behind mouth; portion visible in a mirror
Placement or laryngopharynx
between hyoid and esophagus
Functions of pharynx
passage for food; passage for air; sound production
Larynx
enlargement in airway at top of trachea and below pharynx
Functions of larynx
routes air and food to proper channels; surrounds and protects glands
Epiglottis
projection of cartilage into pharynx that covers opening to trachea
Composition of larynx
muscles and cartilage held together by elastic tissue
Thyroid cartilage
portion of larynx; "adam's apple
Cricoid cartilage
portion of larynx; supports epiglottis when tongue pushes it down
Corniculate cartilage
portion of larynx; muscle attachment for vocal cords
Cuneiform cartilage
portion of larynx; helps stiffen soft tissues in vocal cords; small projections
Cartilages that make up larynx
thyroid; cricoid; arytenoid; corniculate; cuneiform
Vocal cords
folds in the mucous membrane
Types of vocal cords
false vocal cords (produce no sound); true vocal cords (produce sound)
False vocal cords
upper folds; produce no sound; muscles help close larynx during swallowing
True vocal cords
lower folds; produce sounds
Word production
true vocal cords generate sound waves that are turned into words by using pharynx, oral cavity, lips and tongue
Voice pitch
musical quality of voice; controlled by changing tension of cords
Voice intensity
loudness of voice; related to force of air over cords
Glottis
opening between cords
Trachea
flexible tube; connects larynx with bronchii
Composition of trachea
inner wall (ciliated mucous membrane with goblet cells); about 20 c-shaped pieces of hyaline cartilages
Ciliated mucous membranes in trachea
Beat continuously in upward toward throat; expel mucous loaded with debris that will then be swallowed
Functions of trachea
filter incoming air
Functions of cartilage rings of trachea
prevent trachea from collapsing; soft tissue they don't cover allow esophagus to expand
Bronchi formed by:
division of trachea
Hilus of lungs
indentation where bronchi enter
Differences between left and right bronchi
right bronchus is wider, shorter and straighter
Division of bronchi
subdivided into smaller and smaller branches
Layers of respiratory tree
mucosa; submucosa; hyaline cartilage; trachealis muscle
Mucosa composition in respiratory tree
goblet cells in pseudostratified ciliated columnar epithelium
Submucosa composition in respiratory tree
areolar connective tissue with serous and mucous glands
Trachealis muscle composition in respiratory tree
transverse and longitudinal smooth muscle
Trachealis muscles have some control of:
airway resistance; bronchodialation (SNS); bronchoconstriction (PSNS)
Branches of bronchial tree (cartilage decreases)
tertiary bronchi; bronchioles; terminal bronchiles; respiratory bronchioles; alveolar ducts; alveolar sacs; alveoli
Amount of tertiary bronchi in each lung
8 in left; 10 in right
Bronchioles enter _________
lobules
Amount of terminal bronchioles per lobule
50-80/lobule
Amount of respiratory bronchioles
2 or more branch off each terminal bronchiole
Unique function of respiratory bronchioles
first structure to carry out gas exchange
Amount of alveolar ducts
2-10 off each respiratory bronchiole
Alveolar sac characteristics
pouches off alveolar ducts; thing wall sac
Alveoli characteristis
microscopic air sacs; only open into and communicate with the alveolar sacs
Alveoli consist of:
type I alveolar cells; type II alveolar cells; basal lamina; capillary network; CT:fibroblasts
Type I alveolar cells
bulk of alveoli; simple squamous epithelial tissue
Type II alveolar cells
cuboidal epithelial tissues; no gas exchange
Secretions of type II alveolar cells
moisten lungs for gas exchange; prevents collapse of alveoli
Connective tissue in alveoli
Fibroblasts: elastic and reticular fibers; macrophages
Gas transport in alveoli
gas crosses respiratory membrane via simple diffusion through 2 cell layers
Protection of alveoli
macrophages add protection; stay in lungs (fixed)
Prevention of alveolar sticking
surfactant coats gasse=exposed alveolar surfaces
Lung characteristics
Occupy most of thoracic cavity; each lung divides into lobes
Left lung has ___ lobes
2
Right lung has ___ lobes
3
Pulmonary ventilation
moving of air in and out of lungs
External respiration
gas exchange between pulmonary blood and alveoli
Respiratory gas transport
transport of oxygen and carbon dioxide via blood
Internal respiration
gas exchange between blood and tissues
Breathing depends on:
volume changes in thoracic cavity
Volume change leads to:
pressure change
When pressure changes:
gases flow in to equalize pressure
2 phases or breathing
inspiration and expiration
Muscle contraction during inspiration
diaphragm and intercostals muscles contract
Is expiration an active of passive process?
passive
As inspiration muscles relax:
air is pushed out of lungs
Muscles contracted during expiration
internal intercostal muscles