Exam 2 Flashcards
Describe the major functions of the respiratory system
Exchange of gases between the atmosphere and the blood
Regulation of body pH to maintain homeostasis
Protection of body pH to maintain homeostasis
Protection from inhaled pathogens and irritating substances
Sense of smell
Vocalization, production of sound
Describe the parts of the respiratory system
Upper Respiratory System: -Nose and nasal cavity -Paranasal sinuses -Pharynx Lower Respiratory System: -Larynx -Trachea -Bronchial Tree -Alveoli -Lungs -Pleurae
four major respiratory processes
pulmonary ventilation
external respiration
gas transport
internap respiration
pulmonary ventilation
(breathing)
Inspiration=air into the lungs
Expiration=air out of the lungs
external respiration
oxygen (O2) moves from lungs to blood; Carbon dioxide (CO2) moves from blood to lungs
gas transport
transport in blood-works with cardiovascular system
internal respiration
O2 moves from blood to tissue; CO2 moves from tissue to blood
Describe the respiratory mucosa
Mucosa: (or mucous membrane) lines the lumen of all organs that open to the outside of the body, such as respiratory system, digestive system, or urinary system. Consists of the epithelium and a loose areolar connective layer called the lamina propria
how does the mucosa help “condition” air
The Respiratory System conditions the air by warming, humidifying, and filtering
Air needs to be 37 degrees celsius and 100% humidity when it hits the trachea
external nose
the external nose is formed by:
- frontal bone
- nasal bones
- maxillary bones
- hyaline cartilages
- -hyaline cartilages give noses their distinct shape and size
nose
passageway for air conditions air first line of defense respiratory mucosa sneeze reflex sense of smell resonance of speech nasolacrimal duct drains into nasal cavity
anatomy of the nasal cavity
nasal cavity-conducts air from nasal vestibule to nasopharynx
first line of defense-cleans, warms, and humidifies air
nasal conchae-increase surface area of mucosa, “turbinate bones”
paranasal sinuses and nasolacrimal duct drain through small openings into nasal cavity
sneeze reflex, allergies triggered here
sense of smell-olfactory area at top of nasal cavity of cranial nerve 2
nasal cavity two types of mucous membrane
olfactory mucosa
respiratory mucosa
olfactory mucosa
OM
lines the superior of nasal cavity (on superior concha) and contains olfactory neurons extending through cribriform plate of ethmoid bone
respiratory mucosa
pseudo stratified ciliated columnar epithelium with Goblet cells
-cilia move mucus toward the throat
-cilia paralyzed by smoke, become sluggish in cold weather
seromucous glands-mucus and lyzosyme (trap and kill bacteria)
watery mucus humidifies air
sensory nerve endings-sneeze reflex
highly vascular-warming the air, but also result in nosebleed
-filters, warms, and humidifies incoming; reclaims heat and moisture when exhaling
paranasal sinuses
hollow spaces in the skull bones
these air-filled spaces lighten the weight of the skull and add resonance to speech
the spaces are lined by respiratory mucosa, watery mucus secretions drain into the nasal cavity
sinus headache when inflamed, drainage is blocked
frontal, ethmoid, sphenoid, and maxillary bones have sinuses
pharynx
skeletal muscle tube connecting nasal cavity and mouth to esophagus-the “throat”; also directs air to lower respiratory system
nasopharynx
posterior to the nasal cavity passage of air only pseudo stratified ciliated epithelium pharyngeal tonsil (adenoids) pharyngotympanic (eustachian) tube
oropharynx
posterior to the oral cavity
passage of air and food
stratified squamous epithelium
palatine and lingual tonsils
laryngopharynx
posterior to the larynx
passage of air and food
stratified squamous epithelium
food has “the right of way”
conducting zone structures
warms, humidifies, and cleans air (passageways)-includes all the structures that deliver air to respiratory zone
the first 11 branches of the airway
respiratory zone structures
specialized for gas exchange (alveoli)
the 12 branch of the airway until the alveoli (at the 24th branch)
functions of the larynx
provide a patent (open) airway (cartilaginous structure) epiglottis directs food to esophagus and away from airway voice production (vocal ligaments)
larynx arrangement of cartilages
connected by membranes and ligaments (9 cartilages)
thyroid cartilage-edam’s apple
–larger in men after puberty (testosterone)
epiglottis
–elastic cartilage covered by mucosa (stratified squamous epithelium)
–during swallowing the epiglottis closes over opening of larynx
Describe the anatomy of the vocal cords and explain how sound is produced
Vestibular fold (false vocal cord): ridge of tissue, additional protection
Vocal fold (true focal cord): formed by vocal ligaments, vibrate when air moves across-only true vocal cords produce sound
Glottis=opening
Adduct ligaments: increases tension, higher pitch
Abduct ligaments: loosens tension, lowers pitch
Force of air movement: determines loudness
muco-ciliary escalator
cleans the conducting zone
the pseudo stratified ciliated columnar epithelium traps particles in mucous layer, cilia move particles toward the pharynx where they will be swallowed
ciliated pseudo stratified columnar epithelium with goblet cells is considered the typical respiratory epithelium and is seen in the nasal cavity, nasopharynx, larynx, trachea, and larger bronchi
trachea
conducts air from larynx to lungs
windpipe-air passageway from larynx to bronchi entering lungs
at lungs, divides into 2 main bronchi
supported by C-shaped rings of cartilage-complete cartilage front, open in back
carina
ridge of cartilage at bifurcation
trachea wall consists of layers
layers of wall: mucosa (lines lumen), submucosa (cartilage and tracheal), adventitia
hyaline cartilage rings: keep airway open, allow flexibility of airway
tracheal muscle: smooth muscle, flexible wall when food in esophagus
contraction of trachealis:
-narrows passageway-block foreign objects
-increases force of air during coughing (>100 mph)
heimleich maneuver
uses air from lungs to force object out-only if complete obstruction
trachealis
smooth muscle cell layer that controls trachea diameter
how many times does the bronchial tree branch
23 times
describe the branching of the bronchial tree
The trachea branches into two primary or main bronchi: one to each lung
The right primary bronchus is wider, shorter, and more vertical
Carina-ridge of cartilage at branch point of main bronchi
Aspirated objects tend to end up in right lung
Secondary or lobar bronchi-to lobes of lung (3 to right lung, 2 to left lung)
Tertiary or segmental bronchi-to segments of lung
Bronchial tree branches about 23 times
what changes are associated with the branching of the bronchial tree
Support structures change: from cartilage C rings in trachea, to irregular cartilage plates in bronchi-cartilage is lost completely by bronchioles. Elastic fibers in the walls increase
Epithelium type changes: gradual transition from ciliated pseudostratified columnar to columnar to cuboidal. Mucus secreting cells and cilia gradually decrease
Amount of smooth muscle increases in smaller airways: smooth muscle in walls of bronchioles allows changes in air flow resistance (bronchoconstriction, bronchodilation)
histology of bronchus of the bronchial tree
bronchus (bronchi): ciliated pseudo stratified epithelium with goblet cells; hyaline cartilage plates in wall for support, some smooth muscle and elastic fibers; smaller bronchi have less cartilage and more smooth muscle in wall
histology of bronchioles of the bronchial tree
simple columnar to simple cuboidal epithelium, few goblet cells or cilia; smooth muscle and elastic fibers in walls instead of cartilage plates
terminal bronchioles
the smallest bronchioles in the conducting zone
respiratory zone
defined by the presence of thin-walled air sacs called alveoli
respiratory bronchioles
where the first alveoli are seen
bronchioles start to have alveoli in walls so are part of respiratory zone (gas exchange starts to occur)
alveolar ducts
straight areas with alveoli
gas exchange occurs across thin walls of alveoli
alveolar sacs
clusters of alveoli
gas exchange occurs across thin walls of alveoli
transition from conducting zone to respiratory zone
smooth muscle fibers in walls of bronchioles
elastic fibers surround the alveoli
thin walled alveoli allow gas exchange
alveolar pores
connect alveoli and allow air pressure to equalize
cell types in alveoli
type 1 alveolar cells
type 2 alveolar cells
alveolar macrophages
type 1 alveolar cells
squamous cells form walls of alveoli
type 2 alveolar cells
secrete surfactant
alveolar macorphages
phagocytize debris, bacteria
surfactant
a detergent like compound that reduces surface tension in alveoli; essential to prevent alveolar collapse (respiratory distress syndrome)
respiratory membrane
- 5 um thick barrier to gas exchange
- type 1 alveolar cells
- fused basal lamina
- capillary endothelium
gross anatomy of the lungs
the lungs occupy a large part of the thoracic cavity bounded by the ribs, diaphragm, and mediastinum
each lung is surrounded by pleurae, or pleural sac within thoracic cavity
right lung has 3 lobes
left lung has 2 lobes and cardiac notch
accessory structures critical for lung function
thoracic cage, ribs and thoracic cavity-protection and mechanical support respiratory muscles (skeletal muscle)-volume changes during pulmonary ventilation
each lung is surrounded by a pleural sac or pleurae
the pleurae form a thin, double layered serosal sac surrounding the lungs
consits of the parietal pleura and visceral pleura. Between these two pleuras is the pleura cavity
parietal pleura
cover thoracic wall, superior face of diaphragm, and lateral wall of the mediastinum
visceral pleura
cover the external lung surface
pleura cavity
space between layers-filled with small amount of pleural fluid
the lungs receive ___ pressure, ____ volume circulation
low; high
pulmonary arteries
bring low oxygen blood to lungs (blue)
pulmonary veins
carry high oxygen blood away from lungs (red)
who brings oxygenated blood to lungs?
bronchial arteries (branches from thoracic aorta)-supply oxygenated blood to lung tissue such as walls of bronchi, bronchioles *most venous blood returns to heart via pulmonary veins
pulmonary circuit
low pressure but high volume-ALL the body’s blood has to be oxygenated; lungs location of enzymes that act on substances carried in blood
what leads to the bronchopulmonary segments
tertiary bronchi
- each bronchopulmonary segment is served by its own artery, vein, and tertiary bronchus
- the segments are separated by connective tissue which makes it possible to surgically remove only damaged regions
auscultation
using a stethoscope to listen to lung sound
what degree of surface tension is there between the parietal an visceral layers and why is it important
there is a high degree of surface tension between the parietal and visceral layers which is important for the mechanics of breathing-when the thoracic cavity expands, lungs tend to follow
what are the two phases of pulmonary ventilation
inspiration (inhalation): air flows into the lungs
expiration (exhalation): air flows out of the lungs
atmospheric pressure (Patm)
pressure exerted by the air on the body
-at sea level, Patm=760 mmHg=1 atm
-by convention we consider Patm=0 mmHg, so we don’t have to consider altitude differences
-we really only care about pressure relationships not specific values
EX: +1 mmHg or -1 mmHg compared to Patm
*air will flow from an area of high pressure to an area of low pressure
intrapulmonary pressure
(intra-alveolar)
Ppul
is the pressure in the alveoli
will oscillate with breathing, but always equalize to atmospheric pressure in between breaths
intrapleural pressure
Pip
the pressure in the pleural cavity
will oscillate with breathing, but always negative (-4 mmHg) to intrapulmonary pressure
why is Pip negative?
balance between tendency of alveoli/lungs to collapse (elasticity, surface tension) and tendency of thoracic cavity to expand (elasticity of chest wall)
transpulmonary pressure
Ppul-Pip
prevents lungs from collapsing
pneumothorax
air in the pleural cavity
intrapleural pressure becomes equal to atmospheric pressure
hemothorax
blood in the pleural cavity
boyle’s law
the pressure of a gas within a container is inversely related to the volume of the container
- if the volume of a container that contains a gas is reduced, the pressure increases. If the volume increases, the pressure decreases
- pressure and volume are inversely related*
dalton’s law
the total pressure exerted by a mixture of gases is the sum of the pressures exerted by the individual gases
henry’s law
when a gas is in contact with a liquid, the gas will dissolve in the liquid in proportion to its partial pressure
pulmonary ventilation requires ____ change in the thoracic cavity
volume
during ___ the thoracic cavity (intrapulmonary volume) increases and pressure (Ppul) decreases
inspiration
quiet inspiration
active process requiring energy-diaphragm contracts and lowers. External intercostal muscles contract-pulls ribs up and out. both actions increase thoracic volume
during ___ the thoracic cavity (intrapulmonary volume) decreases and pressure (Pull) increases
expiration
quiet expiration
passive process-diaphragm and external intercostals relax-volume of the thoracic cavity decreases
what is necessary to keep lungs inflated
Pip
quiet breathing
inhalation-diaphragm and external intercostals contract
exhalation-is passive; diaphragm and external intercostals relax, chest recoils
forceful breathing
inhalation-diaphragm, external intercostals, sternocleidomastoid, scalenes, and serratus anterior all contract
exhalation-internal intercostals and abdominal muscles contract to compress thoracic cavity
factors impacting efficiency of pulmonary ventilation
airway resistance
alveolar surface tension
lung compliance
airway resistance
largely determined by airway diameter
- bronchoconstriction-contraction of smooth muscle-parasympathetic NS, irritants, histamine (protective function)
- bronchodilation-relaxation of smooth msucle-sympathetic NS-epinephrine, norepinephrine (fight and flight)
- resistance can also be increased by mucus accumulation, infectious material or tumors
alveolar surface tension
thin fluid layer in alveoli creates surface tension and resistance to stretch (expansion)
surfactant reduces alveolar surface tension allowing for inflation
-premature babies-infant respiratory distress syndrome (IRDS)
lung compliance
the ability of the lungs to stretch (expand)
- degree of alveolar surface tension-greater compliance with surfactant
- distensibility of lung tissue
- ability of chest wall to move
ventilation can be measured by
spirometry
what are the four volumes measured in spirography
tidal volume (TV)
inspiratory reserve volume (IRV)
expiratory reserve volume (ERV)
residual volume (RV)
tidal volume (TV)
amount of air that moves into and out of lungs in quiet breathing
inspiratory reserve volume (IRV)
the amount of air that can be inspired forcefully beyond the tidal volume
expiratory reserve volume (ERV)
the amount of air that can be expelled from the lungs after a normal tidal volume expiration
residual volume (RV)
the amount of air that remains in the lungs, even after the most strenuous expiration
inspiratory capacity (IC)
tidal volume (TV) and inspiratory reserve volume (IRV)
functional residual capacity (FRC)
expiratory reserve volume (ERV) and residual volume (RV)
vital capacity (VC)
inspiratory capacity (IC), tidal volume (TV), and expiratory reserve volume (ERV)
total lung capacity
inspiratory reserve volume (IRV), tidal volume (TV), expiratory reserve volume (ERV), and residual volume (RV)
why are respiratory volumes and capacities important
respiratory volumes and capcities measurements can be useful for evaluating loss in respiratory function and following preogression (or recovery) from respiratory disease.
- can’t diagnose specific diseases
- distinguishes between obstructive pulmonary diseases versus restrictive pulmonary diseases
obstructive pulmonary diseases
incrased airway resistance
- chronic bronchitis, emphysema, asthma, cystic fibrosis
- total lung capacity (TLC), functionsl residucal capacity (FRC), and residual volume (RV) may increase
- lungs hyperinflate, hard to push air out
restrictive pulmonary diseases
involve reduced total lung capcity
- tuberculosis, pneumonia, fibrosis (build up of CT scarring)
- vital capacity (VC), total lung capacity (TLC), functional residual capacity (FRC), and residual volume (RV) decline
- lung expansion is limited for various reasons
anatomical dead space
air that remains in conducting zone during ventilation
- the volume of the conducting zone
- air stuck in dead space doesn’t get to alveoli for gas exchange
- around 150 mL in healthy person
- so, for tidal volume (500 mL) only 350 mL are involved in alveolar ventilation
rate and depth of breathing determine ___ of alveolar ventilation (and gas exchange)
efficiency
minute ventilation
total amount of air that flows into or out of the respiratory tract in 1 minute
alveolar ventilation
takes into accound air in dead space, so is better indication of how much fresh air reaches alveoli
what type of breath is the most effective
slow, deep breaths ventilate the alveoli more effectively than rapid shallow breaths
dalton’s law of partial pressures
the total pressure exerted by a mixture of gases is the sum of the individual pressures exerted by each of the gases. the partial pressure of a gas will be proportional to its percent composition in the mixture
what happens to partial pressures when air is humidified
when air is humidified, the partial pressure of water vapor increases, and the partial pressure of oxygen and carbon dioxide decreases
external respiration occurs in the
lungs
-allows for the uptake of oxygen and unloading of carbon dioxide
internal respiration occurs in the
tissues
efficiency of external respiration depends on what 3 factors
partial pressure gradients and gas solubility
thinness and surface area of the respiratory membrane
ventilation-perfusion coupling
external respiration partial pressure gradients and gas solubility
O2 and CO2 will move according to their gradients
- O2 high in alveolus, low in pulmonary capillary
- CO2 low in alveolus, high in pulmonary capillary
external respiration thinness and surface area of the respiratory membrane
thinness and surface area available for exchange can be reduced by:
-edema (water in the lungs)-pneumonia
-emphysema-destruction of alveolar walls, congestive heart failure
-tumor
-mucus
-inflammation
can result in hypoxia (low oxygen in blood) and hypercapnia (high CO2 in blood)
external respiration ventilation-perfusion coupling
blood flow (perfusion) is affected by PO2 levels. Perfusion is controlled by arteriole diameter: if PO2 high, arterioles dilate to pick up oxygen, if low, arterioles constrict
air flow or ventilation is affected by PCO2 levels. ventilation is controlled by bronchiole diameter: if PCO2 high, bronchioles dilate to blow off CO2
result: diversion of blood flow and air flow away from diseased areas of hte lung to healthier areas of the lung and therefore a better match of ventilation-perfusion coupling
internal respiration partial pressure gradients and gas solubility
gases follow pressure gradients:
- O2 high in systemic capillary, low in tissue cell
- CO2 low in systemic capillary, high in tissue cell
external respiration and internal respiration are driven by differences in gas pressure gradients
ER: blood leaving lungs will have a PO2=104 mmHg, PCO2=40 mmHg
IR: blood leaving tissues will have a PO2=40 mmHg, 45 mmHg
oxygen is carried by ___ in RBCs
hemoglobin
structure of hemoglobin
hemoglobin is madeup of 4 polypeptide subunits, each containing a heme group
the iron atom (Fe) in each heme group can bind to one oxygen molecule (O2)
each hemoglobin molecules can bind 4 oxygen molecules
if hemoglobin is fully saturated, it has four O2 molecules bound to it
how is oxygen transported to the tissues
the majority of oxygen molecules (~98.5%) are transported from the lungs to the tissues by hemoglobin inside red blood cells
a small percentage is transported directly dissolved in plasma. O2 is not very soluble in water, so only ~1.5% of O2 is transported in plasma
oxyhemoglobin
HbO2
hemoglobin with oxygen bound
deoxyhemoglobin
HHb
hemoglobin that has released oxygen
the oxygen-hemoglobin dissociation curve
describes how the partial pressure of oxygen in different tissues controls whether hemoglobin reversibly binds or releases oxygen
it shows how local PO2 controls loading and unloading from hemoglobin
hemoglobin exhibits cooperative binding
under normal restin conditions 98% of the hemoglobin in systemic arteries is fully saturated
as blood passes through capillary beds in the tissues, oxygen is delivered to cells and the hemoglobin is 75% saturated or partially saturated
-this means venous blood still is 75% saturated=venous return
cooperative binding
each O2 binding increases the affinity for the next O2 molecule (sigmoid shape of the curve)-this means that both loading and unloading of O2 is efficient
what does it mean when the oxygen-hemoglobin dissociation curve is shifted left
at a given partial pressure of O2, hemoglobin holds onto more of its O2=it is more saturated
what does it mean when the oxygen-hemoglobin dissociation curve is shifted right
at a given partial pressure of O2, hemoglobin releases more of its O2=it is less saturated
hemoglobin’s affinity for O2 is decreased in ___ pH and ___ PCO2
low; increased
both declining pH (more acidic) and increased PCO2 weaken the HbO2 bond: this is called the Bohr Effect and makes it possible for hemoglobin to release more O2 in the tissues, where it is needed during metabolic activity
what is different about fetal hemoglobin
fetal hemoglobin has a greater affinity for oxygen-facilitating oxygen transfer across the placenta
-this makes it possible for fetal hemoglobin to “pick up” oxygen from maternal blood
what is the difference of maternal blood
maternal blood may have a low PO2 when it arrives at the fetus
if maternal blood arrives at a PO2 of 40 mmHg it may be at 75% saturation for mom, but will provide 90% saturation for the fetus
what are the three forms carbon dioxide is transported from cells to the lungs
1) dissolved in plasma (7-10%-smallest percentage)
2) chemically bound to hemoglobin (around 20%)
- CO2 is bound by hemoglobin and carried as carbaminohemoglobin (HbCO2)
- no direct competition with O2 for binding, but deoxygenated hemoglobin binds CO2 more readily than oxygenated hemoglobin
3) as bicarbonate ions in plasma (around 70%-the predominant method)
- CO2 rapidly binds to H2O in a reaction catalyzed by carbonic anhydrase forming carbonic acid (H2CO3). Carbonic acid is unstable and quickly dissociates into a hydrogen ion (H+) and a bicarbonate ion (HCO3-)
- H+ can bind to Hb triggering the Bohr effect: CO2 loading enhances O2 release
- bicarbonate moves to the blood via faclitated diffusion with Cl-=chloride shift
carbon dioxide must be released at the lungs
1) CO2 diffuses from plasma-low PCO2 in lungs
2) CO2 rapidly dissociates from hemoglobin-low PCO2 in lungs
3) CO2 “released” from bicarbonate ions
- to release CO2 in the lungs we need to free CO2 from its “bicarbonate housing”
- bicarbonate reenters the RBC via another chloride shift and the carbonic anhydrase reaction is reversed
bohr effect and haldane effect synergism
increased PCO2 causes more O2 to dissociate from hemoglobin=bohr effect
dissociation of O2 allows more CO2 to bind hemoglobin=haldane effect
carbon monoxide (CO) poisoning
odorless colorless gas
risk factor in fires or malfunctioning heating systems
hemoglobin has 200X greater affinity for CO than O2
CO outcompetes O2 for heme binding side even at low levels
symptoms: confusion and throbbing headache
hyperbaric (high pressure) therapy or 100% oxygen therapy
what cell types are effector cells of the autonomic nervous system
smooth muscle
cardiac muscle
gland cells
regulation of respiratory system by the NS
glands: production and release of mucous in airways. parasympathetic stimulation increases mucous
smooth muscle in wall of airways: parasympathetic stimulation of muscarinic receptors narrows airways. sympathetic stimulation of beta-2 adrenergic receptors widens airways
what muscles are involved in breathing
the muscles controlling inspiration and expiration are skeletal muscles under the control of the somatic nervous system (breathing is not automatic)
- diaphragm is controled by lower motor neruons in C3-5 spinal cord forming the phrenic nerves
- intercostal and accessory muscles of respiration are controlled by lower motor neurons in thoracic spinal cord
- respiratory centers in the brainstem contain the upper motor neurons controlling the lower motor neurons
ventral respiratory group
stimulates breathing-sets normal rate of breathing; overdose of morphine or alcohol inhibits VRG
ventral respiratory group inspiration
inspiratory neurons fire in VRG and increase activity in the phrenic nerve (diaphragm) and intercostal nerve (external intercostal)
ventral respiratory group expiration
epiratory neurons fire in the VRG and decrease activity in phrenic and intercostal nerve allowing muscle relaxation and lung recoil
dorsal respiratory group
(DRG) is an integrating center receiving information from peripheral stretch and chemoreceptors modifying VRG neruon activity
pontine respiratory group
“smooth” transitions between inspiration and expiration
-vocalization, sleep, exercise change pace of transitions
what happens when the high cervical spinal cord is injured
injury to the high cervical spinal cord disrupts communication from the respiratory centers to the lower motor neurons in the cervical spinal cord
-injuries in C1-C3 spinal cord often result in death because breathing stops
hypercapnia
rising PCO2 levels in the blood-indirecly stimulates respiratory centers to increase breathing rate
hypocapnia
low PCO2 levels-can be a result of hyperventilation-if PCO2 too low-respiration is inhibited, apnea (no breathing)
hyperventilation
if PCO2 too low, respiration inhibited, apnea can occur: swimmer blackouts
pH rises: alkalosis
hypoventilation
shallow breathing
PCO2 too high
pH falls: acidosis
CO2 is the most potent chemical signal influencing respiratory rate through ___ chemoreceptors
central
___ chemoreceptors are most sensitive to PO2
chemoreceptors in the carotid body and aortic bodies are sensitive to arterial O2 levles
limited role during normal condition:
-increase sensitivity to PCO2 in low O2 conditions
-arterial PO2 must drop below 60 mmHg before ventilation stimulated
during periods of O2 starvation brainstem centers are depressed and peripheral signlas can ‘jump start’ ventilation
eupnea
normal breathing
apnea
no breathing
dyspnea
labored breathing
COPD
chronic obstructive pulmonary diseases
decreased ability to force air out of lungs
emphysema and chronic bronchitis are examples
common features include high history of smoking, dyspnea-difficult or labored breathing, coughing, pulmonary infections, and respiratory failure-hypoventilation, respiratory acidosis, hypoxemia
asthma
asthma is a reversible obstructive disorder marked by acute epidoses
allergic asthma: inflammation of the airways (can become chronic), constriction of smooth muscle (bronchoconstriction), and increased mucus production
common clinical symptoms: dyspnea-difficult or labored breathing, coughing, wheezing, chest tightness
treatment: fast acting bronchofilators-contain beta adrenergic agonists and inhaled corticosteriods-decrease inflammation through immunosuppression
pulmonary fibrosis
lung tissue becomes damaged and scarred
is a restrictive pulmonary disease that make it difficult to expand the lungs-vital capacity is decreased and ventilation is impaired
scarring and connective tissue in alveoli decrease lung compliance
can be caused by:
-environmental factors: exposure to toxins and pollutants
-cancer therapy
-medical conditions that cause scarring
sleep apnea
very common, 2 types of sleep apnea, patients may have combination of both
temporary cessation of breathing durign sleep
may be more than 30X perminute
disrupts sleep patterns-excessive daytame sleepiness
consequences: susceptibility to accidents and chronic illness such as depression, hypertension, heart disease, stroke, diabetes
treatment: continuous positive airway pressure device (CPAP) and similar devices and lifestyle changes
obstructive sleep apnea
collapse of upper airway
soft tissues of pharynx sag and obstruct airway
more common in men, worse with obsesity
central sleep apnea
reduced drive from respiratory centers of brainstem (CNS)
made worse by opiate use, medication-assisted treatment of substance use disorder
cystic fibrosis
genetic mutation
affects ion chennel that allows Cl- to exit cells
causes sticky mucus to accumulate in air passageways
bacterial infections, chronic inflammation, permanent tissue damage
treatment: mucus dissolving drugs, “clapping” chest and back to loosen mucus
lung cancer
known to aggressively metastasize-early detection with surgical removal of affected area before metastasis provides best potential for cure
major layers of the skin
epidermis and dermis (hypodermis is underneath)
epidermis
keratinized stratified squamous epithelium resting on basement membrane; protective shield
dermis
loose and dense irregular connective tissue; bulk of the skin
hypodermis
loose connective and adipose tissue; anchors skin to muscle
functions of the integumentary system
protection: mechanical trauma, invasion of pathogens, environmental hazards (UV radiation)
sensation: sensory receptors
thermoregulation: maintenane of internal body temperature through negative feedback loops
excretion: waste products (lactic acid, urea, metals) lost through sweat
vitamin D synthesis: UV light reaction with modified cholesterol to produce cholecalciferol
cells of the epidermis
keratinocytes
melanocytes
dendritic (langerhans) cells
merkel (tactile) cells
keratinocytes
production of keritin; desmosomes
melanocytes
synthesize melanin
dendritic (langerhans) cell
phagocytose foreign substances; activate immune system
merkel (tactile) cells
sensory receptor for touch; associated with nerve ending
stratum basale
basal layer; stratum germinativum
- deepest layer attached to dermis
- closest to blood supply
- youngest keratinocytes
- single row of stem cells continually dividing
- 10-25% of cells are melancytes
stratum spinosum
prickly layer several layers thick system of intermediate filaments (pre-keratin) spanning cytosol and connecting to desmosomes appear spiky under microscope-artifact contains dendritic cells
stratum granulosum
granular layer
1 to 5 cells thick
initiate keratinization-flatten, nuclei and orgenelles disintegrate (apoptosis)
prominent cytoplasmic granules
keratohyaline granules-help to form keratin
lamellar granules-contain water-resistant glycolipid (lipid)
epidermal water barrier
cut off from nutrients
stratum lucidum
clear layer
thin translucent band
transition region between S. grulosum and s. corneum
indistinct boundaries between dead keratinocytes
tonofilaments-product of keratohyaline granules clings to intracellular keratin filaments generating parallel arrays
cut off from nutrients
stratum corneum
horny layer
20-30 cell layers thick
anucleate keratinocytes
outermost layer-protect against abrasion and penetration
glycolipid from lamellar granules creates near waterproof layer
terminal cells are cornified (horny)-dandruff and dander
shed 50,000 cells per minute-40 pound in a lifetime!
callus formation-repeated pressure
what are skin layers held together by
desmosomes and hemidesmosomes
dermis layers
papillary layer and reticular layer
papillary layer
20% of thickness
loose areolar connective tissue
dermal papillae-meissner corpuscle, free nerve endings, capillaries
blists
reticular layer
80% of thickness
dense irregular conective tissue
-collagen and elastic fibers (straie-stretch marks)
blood vessels and accessory strucutres (sweat and sebaceous glands; pacinian corpuscle)
epidermal ridges
friction ridges
in thick skin dermal papillae are arranged into dermal ridges
dermal ridges indent epidermis-epidermal ridges
enhanced grip strength
genetically determined-individual specific
sweat pores help generate the finger prints
melanin
ranges from orange-red to black-providing pigment to keratinocytes
synthesized from tyrosine-increased by UV radiation
melanin absorbs UV radiation to protect keratinocyte DNA (shielding like an umbrella)
all humans contain same number of melanocytes, but vary in kind and amount produced
carotene
accumulates in statum corneum of thick skin giving a yellow-orange pigment
hemoglobin
crimson color of oxygenated blood
skin appendages
nails
hair
glands (sweat glands, sebaceous glands)
all derived from the epithelium
nails
scale-like modificatoins of the epidermis
hard keratin-cells do not flake off
nail matrix-nail growth
clinical indicator:
-yellow-tinge-respiratory or thyroid disorder
-thickened yellow-fungal infection
-concavity (spoon nail)-oron deficiency
-horizontal lines (Beau’s lines)-malnutrition
hair
pili-consists of dead, keratinized cells hard keratin-cells do not flake off hair shaft and hair root 3 concentric layers-medulla, cortex, cuticle hair follicle hair bulb-hair follicle receptor (touch) arrector pili smooth msucle
two types of sweat glands
eccrine sweat glands
aprocrine sweat glands
eccrine sweat gladns
more abundant duct extends to a pore at skin surface merocrine secretion of sweat sweat is 99% water -salts, waste, antibodies, dermcidin sympathetic, regulation-forehead to toes "cold-sweat"-emotional
apocrine sweat glands
axillary and anogenital duct empty into hair follicle merocrine secretion of sweat with fatty substances and proteins bacteria on skin produce odor sympathetic regulation-stress human sexual scent glands
skin is important in
regulating body heat (thermoregulation)
-hair, sweat glands, and blood vessels all contribute
sebaceous glands
oil galnds secrete sebum everywhere excepts palms and soles holocrine secretion of sebum sebum is an oily lubricant -lubricatin, slow water loss, bactericidal outgrowth of hair follicle arrector pili contractions force sebum out
erythema
redness
fever, hypertension, inflammation, allergy, embarrassment
pallor
blanching/pale skin
anemia, low blood pressure, anger, fear, stress
jaundice
yellowing liver disorder (bile accumulation in blood)
bronzing
metallic appearance
addison’s disease (pituitary gland tumor)
cyanosis
blue
low amount of hemoglobin and/or red blood cells
burns
denature cell proteins and kill cells of the skin
rule of nines: predict complications and treatment
ABCD rule
asymmetry: two sides of pigmented spot/mole do not match
borde irregularity: boarders of lesion exhibit indentations
color: pigmented spot contains several colors
diameter: spot is larger than 6 mm in diamter
evolution: changes with time
skin is the ____ line of defense
first line of defense skin is a critical barrier between body and environment -chemical barrier -physical barrier -biological barrier
chemical barrier of skin
acid mantle-low pH of skin secretions
sweat (dermicidin), sebum (bacteriocide)
defensins
melanin-chemical sunscreen
physical barrier of skin
bricks and mortar (dead keratinocytes and glycolipids)
water-resistance-preventing loss and entry
organic solvents and heavy metals can cross
biological barrier of skin
dendritic cells
dermal macrophages
DNA converts UV radiation to heat
intact skin epidermis
acid mantle of skin
keratin
intact mucous membranes
mucus nasal hairs cilia gastric juice acid mantle of vagina lacrimation urine
protective chemicals
lysozyme
mucin
defensins
dermicidin
lysozyme
saliva, rspiratory mucus, lacrimal glands
mucin
forms mucus in digestive and respiratory pathways
defensins
antimicrobial peptide
dermicidin
toxic secretion
leukocytes
white blood cells
primary cells responsible for the immune response
leukos: white
hytos: cell
what are leukocytes
derived from hemotopoietic stem cells, which divide into myeloid and lymphoid stem cells
lymphoid stem cells generate
lymphocytes
myeloid stem cells generate
leukocytes
granulocytes
neutrophil
eosinophil
basophil
agranulocytes
lymphocyte (small)
monocyte
chemotaxis
cell movement in an amoeboid fashion following a chemical gradient (movement up the gradient-positive chemotaxis)
phagocytosis
the process of engulfing and ingesting a target pathogen
cells that perform this action are phagocytes-neutrophils and monocytes (macrophages)
cytotoxic cells
attack an ddirectly kill pathogens
esoinophils (parasites) and some lymphocytes (NK cells and T cells)
antigen-presenting cells
cells that display fragments of foreign proteins in thier cell surface
-macrophage/monocyte, lymphocyte (B cells), dendritic cells
phagocytes can ingest ___
foreign pathogens by pathocytosis
opsonization
coating pathogen with opsonins (complement proteins or antibodies)
natural killer cells
are lymphocytes of the innate immune system
NK cells provide a rapid response to virus-injected cells and kill tumor cells
less picky about cellular targets compared to lymphocytes in adaptive immune system
induce cells to undergo apoptosis (programmed cell death), secrete interferons, perforin, and pro-inflammatory chemcials
role of inflammation
attract immune cells and chemical mediators to site of injury
prevents the spread of damage-creating a physical barrier
promotes tissue repair-remove debris/pathogens
cardinal signs of inflammation
redness, heat, swelling, pain
phagocyte mobilization is the
second stage of the inflammatory response
leukocytosis
margination
neutrophils enter first and monocytes follow
monocytes will differentiate into macrophages
pus is the accumulation of dead/dying neutrophiils and macrophages following inflammatory response
leukocytosis
increase in release and production of neutrophils in the red marrow
-4-5 times normal levels of cells
margination
cell adhesion molecules (CAMs) on vessel walls and neutrophils
antimicrobial proteins
interferons help protect uninfected cells from viruses
complement are plasma proteins that help destroy pathogens
-“complements” the innate and adaptive immune system
–opsonization
–enhance inflammation
–insertion of MAC into membranes inducing cell lysis
fever
a systemic response to an invading microorganism
body temperature above normal homeostatic range-36-38 degrees Celsius-febrile
pyrogens are released from damaged cells or pathogens establishing a higher than normal body temperature set point in the hypothalamus
cold “shivers” result from body tying to establish pathological body temperature
unknown physiological benefits:
-liver and spleen sequester ion and zinc-reduce bacterial growth
-increase metabolic rate-sped up tissue repair
-increased activity of phagocytic cells
three important aspects of adaptive immunity:
it is specific, systemic, and has memory
antigens
substances that trigger the adaptive immune system
there are self and non-self antigens
functional properties of complete antigens
immunogenicity and reactivity
immunogenicity
the ability to stimulate specific lymphocytes to proliferate
reactivity
the ability to react with activated lymphocytes and released antibodies
hapten (incomplete antigen)
small molecules (peptides, nucleotides, hormones) that need to nbind endogenous proteins to be recognized
- penicilin, animal dander, detergents
- when unbound have reactivity, but immunogenicity
major types of antigen-presenting cells
dendritic cells: skin
macrophage: lymphoid organs and connective tissue
b cells: present to T helper cells
lymphocyte development
1) origin
2) maturation
3) seeding secondary lymphoid organs and circulation
4) antigen encounter and activation
5) proliferation and differentiation
lymphocytes are ___ during maturation
educated
- immunocomptence
- self tolerance
immunocompetence
must be able to recognize one specific antigen
- B&T cells will display a unique (specific to one antigenic determinant) surface receptor
- all the receptor on one B or T cell are all the same
- B cells display antibodies; T cells display T cell receptors
self-tolerance
must be unresponsive to self-antigens
T cell ‘education’ requires cells to pass two molecular tests
1) positive selection
2) negative selection
active immunity
enhanced secondary immune response results from efficacy of memory B cells
fab region
variable region
forms antigen binding sites and confer specificity
-2 antigen binding sites per antibdody
Fc region
constant region is the same for a given class of antibodies -dictate the type of cell the antibody can bind to -how the antibody functions to eliminate antigens --Fc receptors on immune cells
class 1 major histocompatibility complex (MHC)
found on all nucleated human cells -if cell becomes infected with a pathogen then class 1 MHC will display a non-self atnigen fragment on its cell surface
class 2 major histocompatibility complex (MHC)
is found primarily on antigen presenting cells
T cells mature in the
thymus
T cells can only be activated by an
antigen presenting cell and a double recognition
- t cell receptor recognizes a specific antigen
- CD glycoprotein will recognize the MHC protein on the antigen presenting cell
- -remember the positive and negative selective test performed in the thymys
- co-stimulatory molecules are only present when pathogens are detected
- -“double handshake” betweeen APC and T cell
- process of clonal selection same for both Helper and cytotoxic T cells
- most effector cells undergo apoptosis between 7 to 30 days
helper T cells help facilitate humoral immunity mediated by B cells
helper T cell activation of B cells required for full humoral immunity response
-T cell-independent antigens do not require T cells, but mount a weak response
-T cell-dependent antigens require T cells
similar to co-stimulation molecules between T cells and APCs
helper T cells help activate cytotoxic t cells
more efficient mechanism to activate cytotoxic T cells
- remember cytotoxic T cells can not see class 2 MHC
- APCs express both class 1 and class 2 MHC
- cytokines released attract and stimulate immune cells
cytotoxic T cells are the only T cell that can directly attack and kill cells
two mechanisms to induce cell death:
-perforins and granzymes
-receptor stimulated apoptosis
cytotoxic T cells work in tandem with nateral killer cells to provide immune surveillance
-NK cells can not interact with cells displaying class 1 MHC
-cytotoxic T cells can not see cells without class 1 MHC
allergy
an inflammatory response to a non-pathological antigen
lymphatic system
returns leaked fluids to the cardiovascular system
- network of lymphatic vessels
- lymph
- lymph nodes
lymphoid organs and tissues
structural basis of immune system
-spleen, thymys, tonsils, lymph nodes
immunity
resistance to disease
major functions of the lymphatic and immune systems working together
recognition and removal of abnormal “self” cells
removal of dead and damaged cells
protects body from disease causing invaders
-pathogens:
–microorganisms (microbes)-bacteria, fungi, viruses, single cell protozoans
–parasites (hookworm, tapeworms)
–antigens
-immunogens
–pollen, chemcicals, foreign bodies (splitter)
–antigens
lymph
the fluid that lymphatic capillaries collect
excess extracellular fluid is collected by lymphatic vessels
more fluid is pushed out of capillaries than is drawn in, resulting in accumulation of lfuid in extrcellular space
lymph flows back to bloodstream via a network of lymphatic vessels
collecting vessels–>lymphatic trunks–>lymphatic ducts
lymph enpties into veins close to heart
-thoracific duct drains MOST of body
lymphedema
sluggish flow leads to buildup of lymphatic fluid in extracellular space
what are helpful techniques for improving lymph return
exercising muscles external compression -compression sleeves/wraps -pneumatic cuffs -massage
lymphoid cells
lymphocytes (B cells and T cells)
macrophages
dendritic cells
reticular cells-fibroblast like cells that produce reticular fibers creating a stroma
lymphoid tissue
reticular connective tissue
- diffuse lymphoid tissue: arrangement of lymphoid cells and reticular fibers
- lymphoid follicles (lympoid nodules): solid, spherical bodies packed with lymphoid cells and reticular fibers
primary lymphoid organs
where B and T lymphocutes mature:
- both originate in red marrow
- B cells mature in red marrow
- T cells mature in thymus
secondary lymphoid organs
where mature lymphocytes first encounter antigens and are activated
lymph nodes
clusters of tymphatic tissue located along lymphatic vessels
-hundreds embedded in connective tissue
-clusters in axillae (arm pit), cervical (neck), inguinal (groin), mesenteric (abdominal)
two protective functions:
-cleansing the lymph-macrophages in the node
-immune system activation-site of lymphocyte-antigen ineraction
filters the lymph
the spleen is site of
lymphocyte proliferation, immune surveillance, and blood cleansing
- about the size of a fist
- largest lymphoid organ
- interweaving network of reticular fibers
- filters the blood
- extracts aged and defective RBCs and platelets
- -recycles products
- macrophages remove debris and foreign materials
- stores platelets and monocytes
- erythrocyte production in fetus
two histologically regions of the spleen
white pulp and red pulp
white pulp
immune function
composed of lymphocytes suspended on reticular fibers
forms cuffs around central arteries
red pulp
where word out RBCs and blood borne pathogens are destroyed by macrophages
MALT
mucosa-associated lymphoid tissues
what is MALT
a collection of lymphoid tissue clustered in areas prone to pathogen exposure
where is MALT
found in GI tract, respiratory passages, genitourinary organs
composed of spherical clusters of lymphoid follicles-B cells
