Transcript Respiratory/Digestive PPT

*
*Cellular Respiration: process of releasing E from
food in presence of O2
*Respiration: process by which O2 & CO2 are
exchanged between cells, blood, & air in lungs
*Breathing ≠ Respiration!
*Respiration= exchange of gas
*Breathing= physical movement of air into & out of the
lungs
*
*Supply body with O2 & dispose of CO2
*4 processes:
*Pulmonary ventilation- movement of air in & out of
lungs
* Breathing
*External respiration- movement of O2 from lungs to
blood & CO2 from blood to lungs
*Transport of respiratory gases- transport O2 from
lungs to tissue cells of body & CO2 from tissue cells to
lungs
*Internal respiration- movement of O2 from blood to
tissue cells & CO2 from tissue cells to blood
*Also involved in smell & speech
*
*Air goes in the nose & through the nasal cavity…
*Moistens, warms, filters
*into the pharynx
*passage for air & food
*to the larynx & trachea
*Larynx at the top of the
trachea, contains vocal cords
(voice box)
*Epiglottis – just above larynx,
makes sure no food goes down
trachea
* trachea= windpipe
*
*to the bronchi
*2 large passageways to the
lungs
*to bronchioles
*to
the lungs
*Alveoli- millions of little
air sacs bronchioles go to
* Surrounded by little capillaries
* O2 diffuses across the thin
membranes into the blood and CO2
diffuses in the opposite direction
*Each breath in ≈ 0.4% CO2
and 21% O2, each exhale
<15% O2 and ≈ 4% CO2
*
*Respiratory Zone- site of actual gas exchange
*Microscopic structures- bronchioles, alveolar ducts,
alveoli
*Conducting Zone- all other passageways
*
*Nose- airway for respiration (air enters nostrils),
moistens & warms air, filters & cleans air, serves as
resonating chamber for speech, houses olfactory
receptors
* External- nasal & frontal bones superiorly, maxillary bones
laterally, flexible hyaline cart. inferiorly
* Internal- nasal
cavity- septal cartilage anteriorly, vomer
bone & perpendicular plate of ethmoid posteriorly, ethmoid
& sphenoid bones superiorly, palate inferiorly
* Divided by nasal septum
* Lined with olfactory mucosa & respiratory mucosa
*Paranasal Sinuses- in frontal, sphenoid, ethmoid &
maxillary bones
*lighten skull, help nasal cavity warm & moisten air
*
* Pharynx- 3 parts:
*
nasopharynx- posterior to & continuous with nasal cavity, above where
food enters
* during swallowing, uvula moves superiorly to close off
*
food from entering
oropharynx- posterior to oral cavity- from soft palate to epiglottisair & food
* laryngopharynx- posterior to epiglottis, extends to larynx &
esophagus
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*Larynx- attaches to hyoid superiorly, continuous
with trachea inferiorly
*Provides open airway, switching mechanism to route air &
food, & voice production
*9 cartilages (all but 1=hyaline)
* 1- thyroid, 1- cricoid, 2- arytenoids, 2- cuneiform & 2-corniculate cartilages,
&…
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Epiglottis- elastic cartilage, covered by taste-bud containing mucosa,
extends from posterior of tongue to anchoring point on anterior rim of
thyroid cart
*Vocal ligaments- core of vocal folds= true vocal cords
* Under laryngeal mucosa, attach to arytenoid & thyroid cartilages
* Glottis- vocal cords & opening between them
*
* From larynx, through neck, to mediastinum
* Several layers of mucosa, pseudostratified tissue with goblet cells
*
smoking inhibits & ultimately destroys cilia of psuedostrat. cells
* Outermost layer= connective tissue, reinforced by 16-20 C shaped
rings of hyaline cartilage
*
*
*
elastic elements allow it to be flexible,
rings keep from collapsing despite pressure changes
rings are open in the back so esophagus can still expand when food is
moving down
*
*Bronchial tree= site where conducting zones give
way to respiratory zones
*1º Bronchi- formed by division of trachea
*2º bronchi- subdivision once enters lungs
*3 R, 2 L, 1 to each lobe of lungs
*3º bronchi- divisions of 2º, continue to branch
*Etc…
*
*Bronchioles- air passageways smaller than 1mm
in diameter
*Terminal bronchioles- smallest, less than 0.5mm
*Composition of walls sim of trachea, some
changes as get smaller:
*Support changes: rings  irregular plates  no
cartilage
*Epithelium changes: pseudostratified columnar 
columnar  cuboidal
*Amount smooth muscle s
*
*Define respiratory zone- thin-walled air sacs
*begins as terminal branches feed into respiratory
branches
*Bronchioles lead alveolar ducts, ducts lead into
terminal sacs= alveolar sacs
*Alveolar sacs= like a bunch of grapes, alveoli=
individual grapes
*~300 million alveoli in lungs account for most of
V & provide SA for gas exchange
*Respiratory membrane- simple squamous
epithelium, surrounded by flimsy basement
membrane, covered with cobweb of pulmonary
capillaries
*Pores allow gas exchange & macrophages crawl freely
along surfaces
*
*Paired, occupy all of thoracic cavity except
mediastinum (pleural cavities)
*Costal surface- Anterior, lateral & posterior lung
surfaces (close to ribs)
*Apex- just deep to clavicle, narrow tip of lung
*Base- concave inferior surface, rests on diaphragm
*Hilum- indentation on mediastinal surface,
pulmonary & systemic blood vessels enter & exit &
where each main bronchus enters
*L slightly smaller w/ cardiac notch
*L subdivided into superior & inferior lobes, R
subdivided into superior, middle & inferior lobes
*Lobules- smallest divisions visible to naked eyeeach supplied by large bronchiole & its branches
*
*Blood supply- 2 circulations-pulmonary & bronchial
*Pulmonary arteries deliver systemic venous blood to be
oxygenated
*Bronchial arteries supply systemic blood to lung tissue
*Innervation- parasympathetic & sympathetic motor
& visceral sensory fibers enter each lung through
pulmonary plexus
*Each is cone shaped & suspended in a pleural cavity,
connected to mediastinum by root (vascular &
bronchial attachments)
*Pleurae- thin, double-layered serosa
* Parietal pleura covers thoracic wall, superior surface of
diaphragm, around heart & between lungs
* Visceral pleura- cover external surfaces of lungs
* Pleural fluid fills slit-like pleural cavity- lubes
*
*2 forces cause lungs to pull away from thorax
wall & collapse- 1) lung’s natural tendency to
recoil, 2) surface tension of alveolar fluid
*Pulmonary ventilation- 2 phases- inspiration &
expiration
*Respiratory Pressures
*Intrapulmonary- P in alveoli, s & s with phases, but
always equalizes with atmosphere
*Intrapleural- P in pleural cavity- also fluctuates, but
always a little less than intrapulmonary
*Pulmonary ventilation- depends on changes in
volume of thoracic cavity
*Boyle’s law: P1V1=P2V2
*
* Inspiration-
* Quiet- inspiratory muscles (diaphragm & ext intercostals) activatediaphragm contracts, external intercostals lift up rib cage, volume
thoracic cavity 
* V almost 500mL
* Deep- accessory muscles (scalenes, sternocleidomastoid pec.s, etc)
raise ribs even more to  V even more
* Expiration-
* Quiet- passive process- depends more on lung elasticity than muscle
contraction
* Forced- contraction abdominal wall muscles (oblique & transverse), 
intrabdominal P
*
* Airway resistance- friction- ( major non-elastic source of
resistance or drag in passageways, delta pressure caused by gas
flowing in and out of alveoli)
* F= ∆P/R
* (F = gas flow; P = pressure, R = resistance)
* Alveolar surface tension- helps reduce alveolar size to smallest
possible
* Lung Compliance- very stretchy (if healthy)
* CL= ∆V/∆P- the more it expands, the greater its compliance
* CL = lung compliance; delta V = change in lung volume, delta P = change
in transpulmonary pressure (Ppul – Pip) pulmonary pressure in alveoli –
intrapleural pressure in pleural cavity)
*
* Respiratory Volumes:
*Tidal (TV)- 500mL
*Inspiratory Reserve (IRV)- air that can be forced in
beyond tidal (2100-3200mL)
*Expiratory Reserve (ERV)- air that can be forced out
after tidal (1000-1200mL)
*Residual- even after most strenuous expiration, about
1200mL remains in lungs
*Respiratory Capacities-
*Inspiratory- total air that can be inspired after tidal
expiration (TV + IRV)
*Functional residual capacity- air remaining in lungs after
tidal exhalation (RV + ERV)
*Vital capacity- total amount of exchangeable air (TV + IRV
+ ERV)
*Total lung capacity- sum of all lung Vs, around 6000mL
*
* Alveolar
ventilation (rate) AVR- flow of
fresh gas in & out of alveoli
* AVR= freq. of breaths x (TV- dead space)
*
Anatomical dead space- V of conducting pathways, air fills but does not
contribute to gas exchange, usually about 150mL
*
Alveolar dead space if some alveoli stop working, collapse, obstructed by
mucus
*
Usually ≈ 12 breaths/min x 350mL/breath= 4200mL/min
* Non-respiratory movements- coughing, sneezing, crying, laughing,
hiccups, yawning
*
* Dalton’s Law of Partial Pressures- total P exerted by a mix of
gasses= sum of Ps exerted independently by each gas
* Henry’s Law- when a mix of gasses is in contact with a liquid, each
gas will dissolve in the liquid in proportion to its partial pressure
*
* External Respiration- 3 factors influence movement of O2 & CO2 across
respiratory membrane:
* 1) partial P gradients & gas solubilities~40mmHg, in alveoli ~104mmHg
PO2 in venous blood is only
* PCO2 moves along gentler gradient, 45mmHg in venous to 40mmHg
equilibrium
* 2) Coupling of alveolar ventilation & pulmonary blood flow
* Affect diameter of pulmonary capillaries & bronchioles, in response
to changes of PO2 & PCO2
* 3) Structural characteristics of respiratory membrane
*
Internal Respiration- Same factors, reverse gradients as external
respiration
*
*Bound to hemoglobin (98.5%) or dissolved in
plasma (1.5%)
* Hemoglobin= 4 polypeptide chains, each with
Fe containing Heme group (Fe binds O2)
*Oxyhemoglobin, Deoxyhemoglobin
*Changes in shape,  affinity as each O2 binds & 
Reversible Binding of Oxygen to Hemoglobin
as each is released
*Rate of binding & releasing of O2 depends on PO2,
PCO2, temp, blood pH & BPG
* Normal conditions (PO2 ≈ 100mmHg), hemoglobin is 98%
saturated in arterial blood, 75% in venous blood
* PO2 ≈70mmHg saturation
* temp, H+ &/or PCO2  Hb affinity (enhance O2
unloading)
Oxygen Transport and Saturation in the Blood
*
*Normal active body cells make about 200mL
CO2/min= amount expelled by lungs!
*7-10% dissolved in plasma
*Little more than 20% binds to Hb
carboaminohemoglobin
*Directly influenced by PCO2
* ~70% as bicarbonate ion
*Reacts with H2O and H+, enzymes make reversible
in RBCs, H+ release can change pH
*
*Medullary respiratory centers generate
rhythm & integrate info
*some neurons burst during inspiration others
during expiration (“quiet” ventilation)
* During inspiration send impulse down phrenic &
intercostal nerves to excite diaphragm &
external intercostal muscles
* Expiration uses inhibitory neurons (no
contraction)
*Pons- modifies breathing rhythms &
prevents over inflation of lungs
*
*Depth- how actively respiratory centers stim.
neurons of respiratory muscles
*Rate- how long centers are active or how quickly
they are switched off
*Chemical Factors- sensed by chemoreceptors
(aortic arch & carotids)
*PCO2 -
most powerful respiratory stimulant
* affects central chemoreceptors & diffuses into cerebrospinal fluid
where it releases H+ & excites respiratory centers
*PO2 – must drop really low to have an effect, then 
ventilation causes CO2 & pH   ventilation
*pH – same as effect of H+ from PCO2
*
*Limbic System- through hypothalamusstrong emotion or pain
*or change in temp
*Cortical controls- motor cortex- voluntary
control
*limited
*Pulmonary irritants- vagus nerve
communicates- constrict passageways
*or cough or sneeze
*Inflation reflex- also via vagus nerve-
stretch receptors communicate to stop over
inflation
*
*
* Function- take in & break down food, absorb nutrient molecules,
rid indigestible remains
* Nutrients- substances in food that supply E & raw materials body
uses for growth, repair & maintenance
* Calorie- measure of E in food
* 5 Categories of Nutrients: Carbohydrates, Proteins, Lipids,
Vitamins & Minerals
*
*Carbohydrates- body’s main source of E
* Monomers= monosaccharides
* Simple: mono/disaccharides (sugars), Complex: polysaccharides
(starches)
*Lipids (fats)- cell membranes, myelin sheaths, hormones, oils
for skin & hair, help body store fat soluble vitamins, E
storage
* Monomers= Fatty acids & glycerol
*Proteins- growth, repair, transport, regulation
* Monomers= amino acids
*Vitamins- organic molecules help regulate body processes
* Fat-soluble- A, D, E, K; Water-soluble- B, C
*Minerals- inorganic molecules body needs in small amounts
* Calcium, Iron, Phosphorus, Sodium, Magnesium, etc
*… Water- not technically a nutrient, but essential for life!
*
*
*Alimentary Canal or GI (gastrointestinal) tract
*Mouth, pharynx, esophagus, stomach, small intestine, large
intestine
*continuous, muscular tube, winds through body- digests
food & absorbs digested fragments into blood
*extracellular digestion- digestion takes place outside
body’s individual cells
*Accessory Organs- aide in digestion but food does
not pass through them
*teeth, tongue, gallbladder, digestive/salivary glands, liver,
pancreas, appendix?
*
*Ingestion- taking food in
*Propulsion- moves food in/along alimentary canal
*swallowing
*peristalsis- waves of alternate contraction & relaxation of
muscles in organ walls squeeze food along tract
*churning & mixing
*Mechanical Digestion- physically breaks food into
smaller pieces
*chewing, mixing, churning food
*Peristalsis & rhythmic constrictions of intestine
*Segmentation- mix food with digestive enzymes &
repeatedly move dif. parts of food mass over intestinal
walls to  efficiency of absorption
*
* Chemical Digestion- hydrolysis of large food particles by enzymes
* Hydrolysis- polymers broken into monomers using H2O
* Makes small enough to be absorbed
* Absorption- passage of digested nutrients from lumen of GI into
blood or lymph
* through mucosal cells by active or passive transport
* Defecation- eliminates indigestible wastes (feces)
Dehydration (Condensation)/Hydrolysis Reactions Animated, Review of Biomolecules and Self Quiz
*
* Mechanical & chemical stimuli- receptors in walls of GI tract
* When stimulated activate or inhibit glands or release of hormones,
or mix contents & move along by stimulating smooth muscle of GI
tract
* Mechanoreceptors- respond to stretch of organ
* Chemoreceptors- respond to osmolarity, pH of contents, presence of
substrates & end products of digestion
* Extrinsic & intrinsic mechanisms
* nerve plexuses & hormone-producing cells in organs for secreting or
contracting
*
* Most digestive organs in abdominopelvic cavity, contained in
slippery serous membranes
* Peritoneum- double-layered membrane, parietal peritoneum lines body
wall, visceral peritoneum lines most digestive organs
* Mesentery- double-layer of peritoneum that extends to organs from
body wall, provides routes for blood & lymph vessels & nerves, holds
organs in place, & stores fat
*
*Mucosa- mucus membrane- innermost layermoist epithelial tissue
*Secretes mucus, digestive enzymes & hormones;
absorbs end products into blood; part of 1st line of
defense
*Typically 3 sublayers
* epithelium of columnar tissue with goblet cells
* lamina propria- loose areolar connective tissue
* muscularis mucosae- small layer smooth muscle that can make local
movements of mucus to move food
*Submucosa- moderately dense connective
tissue- has lots of elastic fibers, blood &
lymphatic vessels, & nerves
*
* Muscularis externa- smooth muscle- inner layer is circular, outer
is longitudinal
* Peristalsis & segmentation
* Thickenings form sphincters- prevent backflow as food passes from 1
organ to next
* Serosa- protective outermost layer= visceral peritoneum
*
*Mouth (buccal or oral cavity)
*Anterior= oral orifice, posterior= continuous with
oropharynx, superior= palate, inferior= tongue, lateral=
cheeks
*Teeth for mastication, papillae on tongue (rough surface
area for licking), salivary glands, taste buds & some
defense against pathogens
*Chewing starts mechanical digestion (mastication &
mixing), propulsion is started by swallowing, saliva starts
chemical digestion of starch
*Pharynx- oro & laryngopharynx
*Uvula & soft palate raise & cover nasopharynx during
swallowing
*Stratified squamous mucosa tunic
*Muscle layers, inner= longitudinal, outer= circular,
together peristalsis to force food into esophagus below
*
*Esophagus- muscular tube strait through
mediastinum & diaphragm, to stomach
*Peristalsis with glands to secrete mucus to “grease” walls
*Joins stomach at cardiac orifice, cardiac sphincter acts as
a valve
*Stomach- temporary storage tank for food, nearly
hidden by diaphragm
*Found in left hypochondriac, epigastric & umbilical regions
*Main regions- cardiac region (near cardiac orifice), fundus
(dome-shaped part beneath diaphragm), body- midportion,
& pyloric region- funnel shaped, ends in pyloric sphincter
(controls stomach emptying into small intestine)
*
*Continues digestion of starch, begins digestion of
proteins
*Chyme- creamy paste of food & digestive juices made by
stomach
*Mucosa tunic= simple columnar with LOTS of goblet
cells & gastric glands
*Muscularis externa layer has innermost layer
running oblique rather than circular, allows
propulsion & for stomach to churn- mix & pummel
food
*
*Major digestive organ, food particles prepared to go to
cells
* Completes digestion of starch, protein & fat, absorbs nutrients
& most H2O into blood & lymph
*From pyloric sphincter (in epigastric region) to ileocecal
valve (in R iliac region), joins with large intestine
*2.5-4cm in diameter, 6-7m long!
*3 subdivisions- duodenum, jejunum, ileum
* Bile & pancreatic ducts attach liver, gallbladder & pancreas (all
help with digestion) to duodenum
*Designed to maximize absorption
* Plicae circularis- circular folds force chyme to spiral through
* Villi & Microvilli- extensions on mucosa cells  lumen surface
area
*
*~7cm in diamter, only 1.5m long
*Major functions- absorb remaining H2O (& H2O
soluble vitamins), temporarily stores, then
eliminates (defecation) undigested material (feces)
*3 Subdivsions- cecum (R iliac fossa, largest part,
appendix attached), colon (ascending, transverse &
descending), rectum (in front of sacrum), & anal
canal (only about 3cm long, runs through pelvic floor
to anus)
*Rectal valves separate feces from flatus
*2 sphincters in anal canal
* internal= smooth, external= skeletal
*
*Produce: saliva- cleanses mouth, dissolves food
particles (to be tasted), moistens food, aids in
swallowing, begins chemical digestion
* Composition: ~97-99.5% H2O, slightly acidic, has some defense
proteins, compounds & enzymes
* Amylase- hydrolyzes polysaccharides into monosaccharides
* Lysozyme- helps destroy bacteria
*Location: Submandibular- along medial aspect of
mandible, ducts run under mucosa of oral cavity
floor; sublingual- beneath tongue with ducts into
floor of mouth
*Control: facial & glossopharyngeal nerves
* Response to chemo & mechanreceptors in mouth & some sight, smell, &
stomach irritation
* Produce: gastric juice-
*
* Mucus- helps protect stomach lining
* Hormones- regulate stomach motility & secretion & influence target
digestive organs
* HCl- lowers pH of stomach to ~1.5-3, helps break down proteins,
activates pepsin
* Enzymes- Pepsin- hydrolyzes proteins
* Control: vagus nerve, hormones, & stimuli in head, stomach & small
intestine
*
*Carries out > 500 metabolic & regulatory functions!
*Body’s main chemical factory
*Digestive function- produce bile- emulsifies & helps
digest fat, also major cholesterol excretion from
body
* Yellow/green color from bilirubin
* Common hepatic duct- empties bile from liver & gallbladder to
duodenum
*Detoxifies blood (breaks down alcohol, drugs &
other chemicals, from inside & outside body)
* Bilirubin- remainder of heme group after spleen breaks down used
rbc.s & recycles globin & iron
*Stores blood glucose as glycogen (initiated by
insulin)
* When blood-sugar levels drop too low, liver converts glycogen back to
glucose & releases it to blood
*
* Location: most of hypochondriac & epigastric regions
* 4 lobes- largest= R, sep’d by fissure from L, posterior side=
caudate & quadrate lobes
* Mesentery separates R & L lobes & suspends from abdominal
wall
* Largest gland in body
* Blood rich- “porta hepatic”= hepatic artery, vein & hepatic duct
enter/leave
* Hepatitis- Inflammation of liver, often from viral infections
* A-F
* A & E- transmitted enterically (usually from contamination)
* B & C- transmitted by blood
* Cirrhosis- scar tissue of liver from chronic inflammation from
prolonged alcoholism or chronic hepatitis
*
*Gallbladder- small saclike organ in recess of inferior
surface of R lobe of liver
* Stores & concentrates bile (absorbs H2O & ions, can concentrate up to
10x!)
* Cystic duct from gallbladder joins common hepatic duct to empty in
duodenum
*Pancreas- small tadpole shaped organ, produces
pancreatic juice & secretes hormones (exp. insulin)
* Empties via pancreatic duct to duodenum (typically fuses with common
hepatic duct)
* Composition:
* Mostly H2O, some electrolytes, especially bicarbonate ion- s pH
to ~8, neutralizing acidic chyme
* Enzymes: Amylase- breaks down starch, Trypsin- breaks down
protein, Lipase- breaks down fat