Please enable JavaScript.
Coggle requires JavaScript to display documents.
Justin Cabrera P.6 Respiratory system - Coggle Diagram
Justin Cabrera P.6
Respiratory system
Major functions of the respiratory system
Functions
supply body with O2 for cellular respiration and dispose of CO2
Functions in speech
Functions in olfaction
Respiratory and circulatory system are closely coupled – if either system fails, body’s cells die from oxygen starvation
Respiration processes
Circulatory system
Internal respiration
exchange of O2 and CO2 between systemic blood vessels and tissues
Transport of O2 and CO2 in blood
Respiratory system
External respiration
exchange of O2 and CO2 between lungs and blood
Pulmonary ventilation (breathing)
movement of air into and out of lungs
Upper respiratory structures and functions
Paranasal sinuses
Form ring around nasal cavities
Location:
Sphenoid bones
Ethmoid bones
Frontal bones
Maxillary bones
Functions
Secrete mucus
Help to warm and moisten air
Lighten skull
Pharynx
Connects nasal cavity and mouth to larynx and esophagus
3 regions
Oropharynx
Palatine tonsils located in lateral walls of fauces
Lingual tonsil located on posterior surface of tongue
Passageway for food and air from level of soft palate to epiglottis
Laryngopharynx
Posterior to upright epiglottis
Extends to larynx, where it is continuous with esophagus
Passageway for food and air
Nasopharynx
Soft palate and uvula close nasopharynx during swallowing
Pharyngeal tonsils (adenoids) located on posterior wall
Air passageway (only air) posterior to nasal cavity
funnel-shaped muscular tube that runs from base of skull to vertebra C6
Composed of skeletal muscle
Nose and nasal cavity
Functions of nose
Filters and cleans inspired air
Moistens and warms entering air
Provides an airway for respiration
Houses olfactory receptors
Serves as resonating chamber for speech
Two separate regions
Nasal cavity
Location:
Found within and posterior to external nose
Divided by midline nasal septum
Septum formed anteriorly by septal cartilage
posteriorly by vomer bone
and perpendicular plate of ethmoid bone
Nasal Vestibule
Rest of nasal cavity lined with mucous membranes, pseudostratified ciliated columnar epithelium
Lined with vibrissae (hairs) that filter coarse particles from inspired air
Nasal conchae
Shape of conchae
Increase mucosal area
Enhance air turbulence
Functions
Heat air
Moisten air
Filter air
Scroll-like, mucosa-covered projections that protrude medially from each lateral wall of nasal cavity
External nose
Nostrils (nares)
bounded laterally by alae
Areas
dorsum nasi (anterior
margin)
apex (tip of nose)
root (area between eyebrows) bridge
Only external portion of respiratory system
Lower respiratory structures and functions
Trachea(windpipe)
extends from larynx into mediastinum, where it divides into two main bronchi
Description:
about 4 inches long, 3/4 inch in diameter, and very flexible
Wall Composition
Submucosa
connective tissue with seromucous glands that help produce the mucus “sheets” within trachea
supported by 16–20 C-shaped cartilage rings that prevent collapse of trachea
Adventitia
outermost layer made of connective tissue
Mucosa
ciliated pseudostratified epithelium with goblet cells
Carina
Last tracheal cartilage that is expanded and found at point where trachea branches into two main bronchi
Lungs and alveoli
Anatomy of Lungs
Apex
superior tip, deep to clavicle
Base
inferior surface that rests on diaphragm
Costal surface
anterior, lateral, and posterior surfaces
Hilum
found on mediastinal surface
site for entry/exit of blood vessels, bronchi, lymphatic vessels, and nerves
Root
site of vascular and bronchial attachment to mediastinum
Left lung
separated into superior and inferior lobes by oblique fissure
Cardiac notch
concavity for heart to fit into
Smaller than right because of position of heart
Right lung
separated into superior, middle, and inferior lobes
Middle and inferior lobes separated by oblique fissure
Superior and middle lobes separated by horizontal fissure
Occupy all of the thoracic cavity except for mediastinum
Larynx(voice box)
Opens into laryngopharynx and is continuous with trachea
Functions
Routes air and food into proper channels
Voice production
Houses vocal folds
Speech
intermittent release of expired air during opening and closing of glottis
Provides patent airway
extends from 3rd to 6th cervical vertebra and attaches to hyoid bone
Framework
Paired arytenoid cartilages (anchor vocal cords)
Cricoid cartilage
ring-shaped
Thyroid cartilage
resembles an upright open book; “spine” of book is the laryngeal prominence (Adam’s apple)
large, shield-shaped cartilage
Paired cuneiform cartilages
Paired corniculate cartilages
Epiglottis
Covered in taste bud–containing mucosa
Covers laryngeal inlet during swallowing
Consists of elastic cartilage (not hyaline)
Vocal folds
Vocal ligaments
form core of vocal folds (true vocal cords)
Folds vibrate to produce sound as air rushes up from lungs
Glottis
opening between vocal folds
Vestibular folds (false vocal cords)
No part in sound production
Help to close glottis during swallowing
Diaphragm
large dome shaped muscle
During inhalation, diaphragm contracts & moves inferiorly causing volume of thoracic cavity to increase
During exhalation it relaxes & air is forced out, volume decreases
Bronchi and branches
Conducting zone structures
Gives rise to respiratory zone structures
Trachea divides to form right and left main (primary) bronchi
Right main bronchus wider, shorter, more vertical than left
Main Bronchus
then branches into lobar (secondary) bronchi
Each lobar bronchus supplies one lobe
Three on right and two on left
enters hilum of one lung
Lobar Bronchus
branches into segmental (tertiary) bronchi
Segmental bronchi divide repeatedly
Branches
Bronchioles
less than 1 mm in diameter
Terminal bronchioles
smallest of all branches
Less than 0.5 mm in diameter
Respiratory zone structures
begins where terminal bronchioles feed into respiratory bronchioles
lead into alveolar ducts and finally into alveolar sacs (saccules)
Alveolar sacs contain clusters of alveoli
Sites of actual gas exchange
~300 million alveoli make up most of lung volume
Respiratory membrane
Blood air barrier that consists of alveolar and capillary walls along with their fused basement membranes
allows gas exchange across membrane by simple diffusion
Very thin
Alveolar walls
Scattered cuboidal alveolar cells secrete surfactant and antimicrobial proteins
Single layer of squamous epithelium
Air passages undergo 23 orders of branching
Referred to as bronchial tree
Zones
Conducting zone
Includes all other respiratory structures
Cleanses, warms, and humidifies air
conduits that transport gas to and from gas exchange sites
Respiratory zone
microscopic structures
respiratory bronchioles
alveolar ducts
alveoli
site of gas exchange
Layers of the pleurae
Visceral pleura
membrane on external lung surface
Parietal pleura
membrane on thoracic wall, superior face of diaphragm, around heart, and between lungs
Pleural fluid
fills slitlike pleural cavity between two pleurae
Provides lubrication and surface tension that assists in expansion and recoil of lungs
Pleurae
thin, double-layered serosal membrane that divides thoracic cavity into two pleural compartments and mediastinum
Compare and contrast the mechanism of inspiration and expiration
Expiration
gases exit lungs
Quiet expiration normally is passive process
Volume decrease causes intrapulmonary pressure (Ppul) to increase
Ppul > Patm so air flows out of lungs down its pressure gradient until Ppul = Patm
Inspiratory muscles relax, thoracic cavity volume decreases, and lungs recoil
Forced expiration
active process that uses oblique and transverse
abdominal muscles, as well as internal intercostal muscles
Inspiration
gases flow into lungs
Active process involving inspiratory muscles
diaphragm and external intercostals
Action of intercostal muscles
when external intercostals contract, rib cage is lifted up and out, much like when handle on a bucket is raised
Results in increase in thoracic volume
Action of the diaphragm
Results in increase in thoracic volume
As thoracic cavity volume increases, lungs are stretched as they are pulled out with thoracic cage
Causes intrapulmonary pressure to drop
Because of difference between atmospheric and intrapulmonary pressure, air flows into lungs, down its pressure gradient, until Ppul = Patm
During same period, Pip lowers to less than Patm
Forced (deep) inspirations
occur during vigorous exercise or in people with COPD
Accessory muscles are also activated
Act to further increase thoracic cage size, creating a larger pressure gradient so more air is drawn in
Scalenes, sternocleidomastoid, and pectoralis minor
Mechanical process that depends on volume changes in thoracic cavity
Pressure changes lead to flow of gases to equalize pressure
Volume changes lead to pressure changes
Boyle’s law
relationship between pressure and volume of a gas
Gases always fill the container they are in
If amount of gas is the same and container size is reduced, pressure will increase
So pressure (P) varies inversely with volume (V)
Formula: P1V1 = P2V2
Nonrespiratory air movements
Examples: coughing, sneezing, crying, laughing, hiccups, and yawns
May modify normal respiratory rhythm
Most result from reflex action, although some are voluntary
Many processes can move air into or out of lungs besides breathing
Volume and Pressure relationships in thoracic cavity
Transpulmonary pressure
= (Ppul −Pip)
Pressure that keeps lung spaces open
Keeps lungs from collapsing
Intrapulmonary pressure (Ppul) / intra-alveolar pressure
Pressure in alveoli
Fluctuates with breathing
Always eventually equalizes with Patm
Intrapleural pressure (Pip)
Always a negative pressure (<Patm and <Ppul)
Fluctuates with breathing
Two inward forces promote lung collapse
Surface tension of alveolar fluid
Surface tension pulls on alveoli to try to reduce alveolar size
Lungs’ natural tendency to recoil
Because of elasticity, lungs always try to assume smallest size
Pressure in pleural cavity
One outward force tends to enlarge lungs
Elasticity of chest wall pulls thorax outward
Negative Pip is affected by these opposing forces but is maintained by strong adhesive force between parietal and visceral pleurae
Atmospheric pressure (Patm)
760 mm Hg at sea level = 1 atmosphere
Pressure exerted by air surrounding the body
Respiratory volumes and capacities
Respiratory volumes
used to assess respiratory status
be combined to calculate respiratory capacities
Volumes
Expiratory reserve volume (ERV)
1000–1200 ml
amount of air that can be forcibly expelled from lungs
Residual volume (RV)
amount of air that always remains in lungs
Needed to keep alveoli open
Inspiratory reserve volume (IRV)
amount of air that can be inspired forcibly beyond the tidal volume
2100–3200 ml
Tidal volume (TV)
amount of air moved into and out of lung with each breath
Averages ~500ml
Respiratory volumes and capacities are usually abnormal in people with pulmonary disorders
Spirometer
cumbersome clinical tool used to measure patient’s respiratory volumes
Respiratory capacities
Capacities
Combinations of two or more respiratory volumes
Vital capacity (VC)
sum of TV + IRV + ERV
Total lung capacity (TLC)
sum of all lung volumes (TV + IRV+ ERV + RV)
Functional residual capacity (FRC)
sum of RV + ERV
Inspiratory capacity (IC)
sum of TV + IRV
can give information on a person’s respiratory status
Internal vs. External respiration
External respiration(pulmonary gas exchange)
diffusion of gases between blood and lungs
involves the exchange of O2 and CO2
across respiratory membranes
Partial pressure gradients and gas solubilities
Steep partial pressure gradient for O2 exists between blood and lungs
Venous blood PO2 = 40 mm Hg
Alveolar PO2 = 104 mm Hg
Equilibrium is reached across respiratory membrane in ~0.25 seconds, but it takes red blood cell ~0.75 seconds to travel from start to end of pulmonary capillary
Ensures adequate oxygenation even if blood flow increases 3×
Drives oxygen flow into blood
Internal respiration
diffusion of gases between blood and tissues
involves capillary gas exchange in body tissues
Gas exchange occurs between lungs and blood as well as blood and tissues
Both processes are subject to
Composition of alveolar gas
Basic properties of gases
Disorders of the respiratory system
Tonsillitis
Infected and swollen tonsils can block air passage in nasopharynx
air is not properly moistened, warmed, or filtered before reaching lungs
chronically enlarged, both speech and sleep may be disturbed
Treatment
Surgery to remove it might be necessary (tonsillectomy)
Laryngitis
Effects
changes to vocal tone
speaking is
limited to a whisper
Causes
bacterial infections
very dry air
overuse of the voice
viral infections
tumors on the vocal folds
inhalation of
irritating chemicals
inflammation of the vocal folds that causes the vocal folds to swell
interfering with vibrations
Smoking
inhibits and ultimately destroys cilia
Without ciliary activity, coughing is only way to prevent mucus from accumulating in lungs
When person stops smoking, ciliary function usually recovers within a few weeks
Morning “smoker’s cough” will subside once ciliary function is restored
Tracheal obstruction(Choking)
Life threatening
Suffocation via piece of food that suddenly closed off trachea
Treatment
Heimlich maneuver
procedure in which air in victim’s lungs is used to “pop out,” or expel, an obstructing piece of food
If done wrong could lead to crack ribs
Pleurisy
inflammation of pleurae that often results from pneumonia
Pleurae may produce excessive amounts of fluid, which may exert pressure on lungs, hindering breathing
Inflamed pleurae become rough, resulting in friction and stabbing pain with each breath
Other fluids that may accumulate in pleural cavity
Blood filtrate
watery fluid that oozes from lung capillaries when left-sided heart failure occurs
Blood
leaked from damaged blood vessels
Pleural effusion
fluid accumulation in pleural cavity
Atelectasis
lung collapse due to
Pneumothorax
air in pleural cavity
Treated by removing air with chest tubes
When pleurae heal, lung reinflates
Can occur from either wound in parietal pleura or rupture of visceral pleura
Plugged bronchioles, which cause collapse of alveoli
Obstructive pulmonary disease
increased airway resistance
ex: bronchitis
TLC, FRC, RV may increase because of hyperinflation of lungs
Restrictive disease
reduced TLC due to disease
Ex: Tuberculosis
exposure to environmental agents
Ex: fibrosis
VC, TLC, FRC, RV decline because lung expansion is compromised