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359 Cards in this Set
- Front
- Back
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The respiratory system supplies (1) to tissues and removes (2) from tissues.
|
1. O2
2. CO2 |
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-Site of gas exchange
-bronchioles, alveoli |
Respiratory Zone
|
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-duct system
-also cleanses, humidifies and warms incoming air |
Conducting zone
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-surround nasal cavity
-warms and moistens air -produce mucus |
Paranasal Sinuses
|
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connects the nasal cavity to the larynx and esophagus
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Pharynx (throat)
|
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-Posterior to Nasal Cavity
-Is only an airway -is closed off during swallowing by soft palate and uvula upward -continuous with nasal cavity via internal nares |
Nasopharynx
|
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the nasopharynx is line with?
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ciliated pseudostratified epithelium
|
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the nasopharynx high posterior wall has?
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pharyngeal tonsils (adenoids)
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the oropharynx contains what kind of epithelium?
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stratified squamous epithelium
|
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-posterior to oral cavity
-continuous w/ it through the fauces -runs from soft palate to epiglottis -air and food pass thru |
Oropharynx
|
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The laryngopharynx has what kind of epithelium?
|
stratified squamous epithelium
|
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-air and food pass thru
-posterior to epiglottis -extends to larynx -continuous w/ esophagus |
Laryngopharynx
|
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-attaches to hyoid bone
-opens into laryngopharynx -continuous w/ trachea |
Larynx (voicebox)
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-function of the larynx?
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-provide an open airway
-route air and food intor proper channels -voice production |
|
(____) fuses to form the laryngeal prominance (Adam's apple?
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Thyroid cartilage
|
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Attached to the larynx is?
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cricoid cartilage
|
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What sits on top of trachea?
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cricoid cartilage
|
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anchors vocal chords?
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arytenoid cartilage (cuneiform and corniculate)
|
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-laryngeal muscles relax and contract moving arytenoid cartilage
-changes length of true vocal cords and size of glottis -intermittent release of air |
voice production
|
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Tense vocal cords=
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narrow glottis-->high pitch sound
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Decreased tension of vocal cords=
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wide glottis-->deep tones
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The greater the force of air across vocal cords?
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the increase in vibration of the cords-->increase loudness
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(____) is a resonating chamber and amplifies sound.
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Pharynx
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Speech by muscles in pharynx, tongue, soft palate, and lips.
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Sound
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Inflammation of vocal cords=
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laryngitis
|
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vocal cords also act as a sphincter effectively cutting off trachea when?
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-cough
-sneeze -strain for bowel movement -weight lifting |
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-air trapped in lower resp. tract
-abdominal muscles contract -intrabdominal pressure rises |
Valsalva's Maneuver
|
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from larynx - descends into mediastinum dividing into two bronchi.
4" long flexible |
trachea (windpipe)
|
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the walls of the trachea are?
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either mucosa, submucosa, or adventita
|
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-Pseudostratified ciliated epithelia.
-Cilia propel debris toward pharynx |
Mucosa of trachea walls
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(____) inhibits and destroys cilia in trachea.
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smoking
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(____) is only means of sweeping mucus upward.
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coughing
|
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-a connective tissue layer
-lots of serous and mucus glands |
submucosa of trachea walls,
|
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-a connective tissue layer reinforced by 16-20 open rings of cartilage
-prevents collapsing |
Adventita of trachea walls.
|
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B/C the trachea is very flexible, it (1) during inspiration and (2) during expiration.
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1. stretches
2. recoils |
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In the trachea, open parts of cartilage are connected to the (1), which allows (2).
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1. trachealis muscle
2. esophagus to expand as food passes through. |
|
(____) contracts during coughing.
- - |
Trachealis muscle.
-increases force of expired air up to 100mph -helps expel mucus from trachea. |
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(____) is the last tracheal cartilage before splitting into two primary bronchi.
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Carina
|
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(1) feeds into respiratory bronchioles which feed into (2), which feed into (3).
|
1. terminal bronchioles
2. alveolar ducts 3. alveolar sacs composed of alveoli |
|
-single layer of squamous epithelial cells - type 1 cells
-basal lamina covered by a 'cobweb' of pulmonary capillaries. |
Alveoli
|
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the (___) in the alveoli allow O2 and CO2 to pass easily by diffusion.
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respiaratory membrane
|
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the respiratory membrane consists of?
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alveolar membrane
basal lamina capillary membrane |
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(____) secrete surfactant onto alveolar epithelium.
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cuboidal type II cells of alveoli
|
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b/c water molecules are polar, this creates (____) in the alveoli.
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surface tension
|
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(1) coats alveolar walls pulling them inward. This collapses alveoli when (2).
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1. H2O
2. air expelled during expiration |
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(1) interrupts polar force between H20 molecules, which leads to (2), and (3).
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1. Surfactant (fats and proteins)
2. a decrease in surface tension 3. alveoli do not collapse |
|
b/c premature babies have no (1), the (2), and (3) requires much energy.
|
1. surfactant
2. alveoli collapse between breaths 3. re-inflation |
|
-surrounded by elastic fibers
-have alveolar pores which equalize air pressure in alveolar sacs. -macrophages crawl freely on surface of epith. cells -keep alveoli sterile -macro get swept up to pharynx -swallow 2 million dust cells per hour. |
Alveoli
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(____) sit in the pleural cavity on the thorax.
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Lungs
|
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-Apex of lungs sits?
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just beneath clavicle
|
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the anterior lat. and post. sides of the lungs contact?
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ribs
|
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the inferior (base) portion of the lungs sits on?
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the diaphragm
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Medial surface of the lungs is?
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hilus (indent)
|
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(____) enter lungs at hilus.
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blood vessels + 1 bronchi
|
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left lung is (___) than right.
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smaller
|
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(____) accomadates the heart.
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cardiac notch
|
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the upper and lower lobe of the left lung is separted by?
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oblique fissure
|
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the right lungs has (1) lobes and is separated by (2).
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1. 3
2. oblique and horizontal fissure |
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Lungs are section by connective tissue into?
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bronchopulmonary segments
|
|
-each lung has (1) segments?
-each lung has own (2)? -helps confine (3). |
1. 10
2. bronchus, artery and vein 3. spread of disease |
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the two blood supply circulations of the lungs?
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pulmonary and bronchial circulation
|
|
-delivers de-oxygenated blood for oxygenation in pul. caps.
-returns blood to heart via pulmonary veins -large volume, low pressure |
pulmonary circulation
|
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-low volume, high pressure
-is blood supply to lung tissue -branches from aorta-->hilus-->runs along bronchi |
bronchial circulation
|
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the bronchial circulation supplies all lung tissue except?
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Alveoli (supplied by pulmonary circulation)
|
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there are many (____) between the bronchial and pulmonary circulatory systems. so most blood in bronchial circulation returns to heart via the (____).
|
1. anastomoses
2. pulmonary veins |
|
the parasympathetic nerve supply causes (____).
|
bronchial constriction
|
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the sympathetic nerve supply causes (____).
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bronchial dilation
|
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-covers inside thoracic wall and top of diaphragm
-around heart and between lungs |
parietal pleura
|
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the parietal pleura doubles over to become?
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visceral pleura
|
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cover outer walls of lungs
|
visceral pleura
|
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space between parietal and viseral pleura is?
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pleural cavity
|
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pressure changes are described relative to?
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atmospheric pressure = 760 mmHg
|
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During inspiration-at rest what happens?
|
-the dome shaped diaphragm contracts - moves downward - increases volume of thorax
-the external intercostal muscles contract lifting rib cage. |
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the pressure in the alveoli is the?
|
Intrapulmonary pressure - P(alv)
|
|
P(alv) - (____) with the phases of breathing.
-but at the end of inspiration and expiration it (____). |
-rises and falls
-equals P(atm) |
|
the pressure in the pleural cavity is called?
|
Intrapleural pressure - P(ip)
|
|
-fluctuates w/ breathing
-always about 4 mmHg less than P(alv) |
Intrapleural pressure P(ip)
|
|
(____) is always negative
Why? |
Intrapleural pressure P(ip)
b/c it is always about 4mmHg less than intrapulmonary pressure - P(alv) |
|
Why is intrapleural pressure always negative?
|
b/c two forces pull lungs away from thorax. i.e. pull viseral pleura away from parietal pleura.
|
|
What are the two forces that cause intrapleural pressure to be negative?
|
1. Elasticity of the lungs causes lungs to recoil to smallest size.
2. surface tension of the alveolar fluid acts to collapse alveoli. |
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The two forces want to separate visceral pleura from parietal pleura, but fluid (pleural) is?
|
strong, b/c cohesive bonds secure pleura together. Opposing forces instead cause negative intrapleural pressure.
|
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If P(ip) = P(alv) or P(atm), then?
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lung wall collapse pneumothorax (Atelectasis)
|
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Pulmonary (lung) ventilation is based on?
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boyle's law P1V1 = P2V2
|
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Pressure of gas (____).
Therefore? |
varies inversely with it's volume.
Therefore, as volume increases pressure decreases and as volume decreases pressure increases. |
|
during inspiration the volume of the thorax increases by?
|
500 ml
|
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During inspiration what does the P(alv) drop to?
Then what happens? |
P(alv) drops 1 mmHg (i.e. Vacuum)
Air rushes in thru nostrils ~500 ml |
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What happens when P(alv) = P (atm)
|
inspiration ends
|
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During inspiration what is the intrapleural pressure P(ip)?
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-6 mmHg below P(atm) (754 mmHg)
|
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In normal, resting individuals expiration is?
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passive
|
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During expiration the?
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natural elasticity of the lungs reduces lung volume as inspiratory muscles relax.
|
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As the diaphragm becomes dome shaped and the rib cage descends during expiration what happens?
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-decrease in volume of thorax
-decrease in volume of lungs -compresses air inside lungs -P(alv) rise 1 mmHg This forces air out of lungs |
|
in exercising individuals expiration is (____).
|
force by contraction of abdominal muscles.
|
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Factors influencing ventilation
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1. airway resistance
2. alveolar tension forces 3. lung compliance (stretchyness) |
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increase resistance and?
|
it decreases air flow (F)
|
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Greatest resistance to F (air flow) is in?
|
medium sized bronchi
|
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The bronchi are sensitive to?
|
neural control
chemical irritants histamine breathing become strenuous as in acute asthma attack. |
|
Alveolar tension forces are reduced by?
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surfactant
|
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the ease with which lungs can expand?
|
lung compliance
|
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lung compliance is reduced by?
|
-fibrosis (scar tissue)
-thick mucus (pneumonia, bronchitis) -reduced production of surfactant. |
|
respiratory volumes are recorded using a?
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spirometer
|
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vol. of air inhaled (then exhaled during quiet breathing
|
tidal volume
|
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normal tidal volume is approximately
|
500 ml
|
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amount of air inspired forcibly beyond tidal volume.
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inspiratory reserve volume
|
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normal inspiratory reserve volume is?
|
2100-3200 ml
|
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amount of air exhaled from lungs beyond tidal volume
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expiratory reserve volume
|
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normal expiratory reserve volume is?
|
1000-1200 ml
|
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amount of air that remains in lungs preventing lung collapse - 1200 ml
|
residual volume
|
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sums of respiratory volumes and indicate a person's respiratory status.
|
respiratory capacities
|
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volume of air inspired after tidal expiration.
|
inspiratory capacity.
|
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volume of air remaining in lungs after tidal expiration.
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functional residual capacity
|
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vol. of exchangeable air.
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vital capacity
|
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total lung capacity is approximately?
|
6L
|
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examine rate at which gas moves into and out of lungs.
|
pulmonary function test.
|
|
quiet breathing 6L/min or 500 ml/breath at 12 breaths/min
|
Minute (total) ventilation
|
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exhalation of the vital capacity as rapidly as possible - takes longer in obstructive pulmonary disease.
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forced vital capacity
|
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the total pressure exerted by air is the sum of the pressures of each of the gases in air (O2, N2, CO2, H2O)
|
Dalton's Law
|
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(____) is the sum of the pressures exerted by O2, N2, CO2, H2O.
|
760 mm Hg
|
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The contribution of each gas to the total pressure (760 mm Hg) is equal to the (____).
|
percentage of the gas in the air.
|
|
What is the percentage of nitrogen (N2) in air and how many mm Hg does that account for?
|
78.6% and 597 mm Hg
|
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What is the percentage of oxygen (O2) in air and how many mm Hg does that account for?
|
21% and 159 mm Hg
|
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What is the percentage of CO2 in air and how many mm Hg does that account for?
|
0.04% and .3 mm Hg
|
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What is the percentage of H2O in air and how many mm Hg does that account for?
|
0.46% and 3.7 mm Hg
|
|
What are the individual pressures called of air molecules?
|
Partial Pressures
|
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In air, what is PO2 and PCO2?
|
PO2=159 mm Hg
PCO2=0.3 mm Hg |
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In the alveoli there is (1) CO2, H2O and (2) O2.
|
1. more
2. less |
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Why is there more CO2, and H2O in the alveoli and less O2?
|
-O2 is diffusing into the blood
-CO2 is diffusing into the lungs -Air has been humidified -Alveoli air is a mixture of old and new air. |
|
What is PO2 and PCO2 in alveoli?
|
PO2=104 mm Hg
PCO2=40 mm Hg |
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What is PO2 and PCO2 in the pulmonary capillaries?
|
PO2=40 mm Hg
PCO2=45 mm Hg |
|
(1) and (2) diffused down their concentration gradients.
|
1. O2
2. CO2 |
|
Gradient for (1) is less steep than for (2) but (3) is 20 times more soluble than (4) - so (5) readily diffuses across respiratory membrane.
|
1. CO2
2. O2 3. CO2 4. O2 5. CO2 |
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If alveolar PO2 is low --> (____)
|
terminal arteriole constricts
|
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If alveolar PO2 is high --> (____)
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terminal arteriole dilates
|
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If alveolar PCO2 is low --> (____)
|
bronchiole constricts
|
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If alveolar PCO2 is high --> (____)
|
bronchiole dilate which allow CO2 to be exhaled more easily.
|
|
When O2 binds to hemoglobin it is called?
|
oxyhemoglobin
|
|
How many O2 molecules can Hb bind to?
|
4
|
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After first O2 binds the 2nd, 3rd, and 4th binds how?
|
2nd and 3rd binds more easily, and the 4th binds even more easily.
|
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After unloading 1st O2, 2nd, 3rd, and 4th detaches how?
|
2nd and 3rd detach more easily and 4th O2 detaches even more easily.
|
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The loading and unloading of O2 by Hb creates an?
|
S-shaped dissociation curve.
|
|
At top of curve PO2=
Arterial blood is? |
104 mm Hg
Arterial blood is 100% saturated with O2 |
|
In tissue PO2=
why? |
40 mm Hg
O2 unloaded from Hb, but Hb is still 75% saturated with O2. |
|
What is the significance of our oxygen transport system?
|
1. O2 loading and delivery to tissues is adequate even when PO2 inhaled is below normal
2. Only 25% of O2 is unloaded from Hb during one systemic circuit |
|
When is the inhalation of PO2 below normal?
|
higher altitudes
lung disease smoking |
|
At PO2 70 mm Hg - Hb is?
|
95% saturated with O2
|
|
What is the significance that only 25% of O2 is unloaded from Hb during one systemic circuit?
|
-we have a huge reserve of O2 in RBC's.
-During increase metabolic activity can use this O2 before increasing resp. rate. |
|
When will the dissociation curve for oxygen transport shift to the right?
|
Increasing temp
Increasing PCO2 Increasing H+ |
|
What does it mean when the dissociation curve shifts to the right?
|
there is a decrease in Hb affinity for O2 so more O2 is now available to tissues.
|
|
When will the dissociation curve for oxygen transport shift to the left?
|
Decreasing temp, PCO2, and H+
|
|
What does it mean when the dissociation curve shifts to the left?
|
there is an increase in Hb affinity for O2 so less O2 is released from Hb as not needed by tissue.
|
|
Cells of body produce (____) of CO2 each minute.
|
200 ml
|
|
CO2 is transported in blood how?
|
1. Dissolved in plasma 7-10%
2. Bound to Hb 20% - carbamino Hb 3. In plasma as bicarbonate (HCO3-) 70% |
|
CO2 + H2O <=> H2CO3 <=> H+ + HCO3-
Which reaction occurs faster in RBC's and why? |
The 1st reaction occurs much faster in RBC's due to carbonic anhydrase.
|
|
(1) diffuses out of RBC, so (2) replaces the negative charge.
What is this called? |
1. HCO3-
2. Cl- The chloride shift. |
|
Normally the H+ released by dissociation of H2CO3 is buffered by?
|
Hb
|
|
If H+ levels begins to rise what happens?
|
H+ combines with HCO3- --> H2CO3. This removes H+ and normalizes pH. (and vice versa)
|
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If there is a decrease in ventilation what happens CO2, H2CO3, and pH? What is this condition called?
|
Inc. in CO2 in blood, inc. H2CO3, and dec. pH of blood.
Condition called acidosis. |
|
If there is an increase in ventilation what happens CO2, H2CO3, and pH? What is this condition called?
|
dec CO2 in blood, dec. H2CO3, and inc. pH of blood.
Condition called alkalosis. |
|
What has basic control of respiration?
|
clusters of neurons in medulla called the Medullary Respiratory Centers.
|
|
Name the two Medullary Respiratory Centers.
|
1. The Dorsal respiratory Group - DRG
2. The Ventral Respiratory Group - VRG |
|
Which one of the medullary respiratory centers contains the pacemaker cells?
|
The Ventral respiratory group - VRG
|
|
the rhythmic generating and integrative center
|
The Ventral respiratory group - VRG
|
|
When the VRG's Inspiratory neurons fire what happens?
|
1. nerve impulses are sent along the phrenic and intercostal nerves.
2. External intercostal muscles and diaphragm contract 3. Thorax expands and lungs inflate (759 mmHg) 4. Air moves into the lungs |
|
When the VRG's Expiratory neurons fire, what happens?
|
1. nerve impulses along the phrenic and intercostal nerves stop.
2. External intercostal muscles and diaphragm relax. 3. Thorax reduces volume and lungs deflate (761 mmHg) 4. Air moves out of the lungs. |
|
Normal respiratory rhythm is?
-inhalation = -exhalation = -normal rate and rhythm is called? |
12-15 times/min
inhalation=2 sec exhalation=3 sec Eupnea |
|
not breathing
|
Apnea
|
|
inability to breath lying down
|
orthopnea
|
|
abnormal breathing pattern, often seen just before death - tidal volume changes followed by apnea.
|
Cheyne-strokes breathing
|
|
VRG can be completely suppressed by an overdose of?
|
-sleeping pills
-morphine -alcohol |
|
What does the DRG do?
|
integrates input from stretch and chemoreceptors (in aortic arch and carotid arteries) and send this to the VRG.
|
|
Modify the activity of Medullary Neurons.
1. Smooth out transition from inhalation to exhalation and vice versa. |
Pontine Respiratory Centers
|
|
How does the pontine respiratory group work?
|
transmits impulses to the VRG.
|
|
Fine tunes rhythm generated by the VRG during
-Vocalization -Sleep -Exercise |
Pontine Respiratory Group (pneumotaxic center)
|
|
Factors that modify rate and depth of breathing
|
lung receptors activated by irritants (mucus dust, smoke, noxious fumes, etc...)
Stretch receptors (baroreceptors) in visceral pleurae. |
|
send impulses to medulla to end inspiration.
|
stretch receptors (baroreceptors) in visceral pleurae.
|
|
When the stretch receptors in the visceral pleurae ends inspiration, then what?
|
As lungs recoil receptors go quiet - can inhale again. This is the Hering-Breuer (inflation) reflex - prevents xs stretching of the lungs.
|
|
What are the accessory digestive organs?
|
-teeth
-tongue -gall bladder -digestive glands -salivary glands -liver -pancreas |
|
alimentary canal, gastrointestinal tract, and guts are all?
|
basically the same thing, organs of the digestive system.
|
|
how long is the alimentary canal?
|
~30ft
|
|
What is the alimentary canal?
|
continuous muscular digestive tube. It digests food and absorbs products of digestion.
|
|
what is the alimentary canal comprised of?
|
1. mouth
2. pharynx 3. esophagus 4. stomach 5. small intestine 6. large intestine 7. anus |
|
Is the GI tract inside or outside the body?
|
Outside
|
|
What are the 6 essential activities for processing of food?
|
1. Ingestion
2. Propulsion 3. Mechanical digestion 4. Chemical digestion 5. Absorption 6. Defacation |
|
Which part of the digestive process is completely voluntary?
|
Ingestion
|
|
taking food into digestive tract
|
ingestion
|
|
swallowing
|
propulsion
|
|
how does propulsion (swallowing) work?
|
peristalsis (alternate waves of contraction and relaxation of muscles)
|
|
chewing churning food in the stomach segmentation (rhythmic local constrictions of intestine) mixes food with digestive juices.
|
mechanical digestion
|
|
food molecules are broken down by enzymes secreted by various glands (begins in mouth, completed in small intestine)
|
chemical digestion
|
|
passage of digested products into blood or lymph. Occurs mostly in SI.
|
Absorption
|
|
elimination of indigestible substances from the body (bacteria)
|
Defecation
|
|
most organs of the digestive system reside in the?
|
abdominopelvic cavity
|
|
organs and cavity are covered in?
|
serous membranes
|
|
covers external surface of digestive organs
|
visceral peritoneum
|
|
the visceral peritoneum is continuous with the?
|
parietal peritoneum
|
|
lines abdominopelvic cavity
|
parietal peritoneum
|
|
between two peritonea is the?
|
peritoneal cavity that contains serous fluid
|
|
-a double layer of peritoneum
|
a mesentery
|
|
in most places the mesentery is?
|
dorsal
|
|
What does the mesentery provide?
|
-routes for blood vessels, lymphatics, an nerves.
-holds organs in place -stores fat |
|
1. inflammation of peritoneum
2. from wound piercing abdomen 3. from perforating ulcer 4. burst appendix 5. very painful 6. friction between peritonea is due to lack of serous fluid |
Peritonitis
|
|
Innermost tissue layer, lines lumen.
|
Mucosa
|
|
Function of the mucosa
|
-secretion of mucus, enzymes, hormones
-absorption -protection against infection |
|
What are the 3 sub layers of the mucosa and what are there functions?
|
1. epithelial lining - mucus secreting
2. lamina propria - loose connective tissue 3. muscularis mucosae - thin layer of smooth muscle cells - twitches to dislodge food. |
|
-dense connective tissue w/ blood and lymphatics
-rich supply of elastic fibers -provides the vascular network to surrounding tissues. |
Submucosa
|
|
-inner circular layer of smooth muscle cells
-outer longitudinal layer of smooth muscle cells -when circular layer thickens it forms a sphincter. |
muscularis externa
|
|
-outermost protective layer - is the visceral peritoneum
|
Serosa
|
|
in the esophagus the serosa is replaced by the?
|
adventitia
|
|
Name the 2 nerve plexii of enteric neurons of the alimentary canal.
|
1. Submucosal nerve plexus
2. Myenteric nerve plexus |
|
-in submucosa
-controls activity of glands and smooth muscle in mucosa |
Submucosal nerve plexus
|
|
-between circular and longitudinal smooth muscle
-Controls GI tract mobility |
Myenteric nerve plexus
|
|
Enteric systems are linked to CNS by?
|
-Afferent visceral nerves
-Efferent sym. and Parasym. ANS |
|
-lined w/ stratified squamous epithelia - due to friction
-continuous w/ oropharynx |
Oral or buccal cavity
|
|
-Grips food
-Mixes food w/ saliva -compacts food into bolus -pushes bolus into pharynx -held in place by the lingual frenulum |
tongue
|
|
secrete saliva
|
salivary glands
|
|
located outside oral cavity - secrete saliva into mouth
|
extrinsic salivary glands (produce majority of saliva: parotid, submandibular, and sublingual)
|
|
scattered throughout the oral mucosa
|
intrinsic salivary glands
|
|
name the type of salivary gland cells.
|
serous - watery fluid full of enzymes
Mucous - stringy, viscous fluid (mucus) |
|
What type of salivary gland cells do the following produce:
-parotid gland -submandibular gland -intrinsic glands -sublingual |
parotid gland-serous cells
submandibular-serous and mucus intrinsic glands-serous and mucus -sublingual-mucous |
|
-mostly water - 98%
-slightly acidic |
saliva
|
|
saliva contains?
|
-Ions
-Amylase - digestive enzymes - begins breakdown of starch -Proteins -Lysozymes-bacterioside -IgA -Metabolic wastes |
|
How much saliva do we produce in a day?
|
1 liter (0.26 of a gallon)/day
|
|
Salivation is controlled by?
|
ANS
|
|
-from mouth food-oropharynx-laryngopharynx
-stratified squamous epithelium -mucus producing glands -constrictor muscles propel food into esophagus |
Pharynx
|
|
The esophagus is?
|
normally collapsed
|
|
-Food propelled from pharynx into esophagus when (____),
|
epiglottis closes of larynx
|
|
The esophagus pierces diaphragm at?
|
esophagus hiatus
|
|
the esophagus joins stomach at (1), which is (2).
|
1. cardiac orifice
2. surrounded by the cardiac sphincter - also called gastroesophageal sphincter (sphincter closes when no food in esophagus) |
|
-expansion of GI tract
-Is a temporary storage tank -Food-creamy paste chyme |
Stomach
|
|
When empty, the stomach is holding?
|
50 mls
|
|
the maximum capacity the stomach can hold is?
|
4L or 1 gallon
|
|
When empty, mucosa and submucosa fold, this is called?
|
rugae
|
|
the superior, dome shaped part of the stomach.
|
fundus
|
|
connects stomach to duodenum and controls stomach emptying.
|
pyloric sphincter
|
|
A mesentery connection from the liver to the lesser curvature of the stomach.
|
lesser omentum
|
|
a mesentery running from greater curvature to the coils of small intestine.
|
Greater Omentum
|
|
Muscularis externa has additional layer of smooth muscle called the (1), which allows (2).
|
1. oblique layer
2. churning and mixing of food. |
|
Digestive process in stomach
|
-physically
-chemically-only chemical digestion is of proteins by pepsin -protein digestion only initiated in stomach -In children-rennin secreted by glands -Absorption of lipid soluble substances |
|
Why is rennin secreted by the glands of the stomach in children?
|
breaks down milk protein casein.
|
|
What kind of absorption does the stomach play in the digestive process?
|
absorption of lipid-soluble substances - alcohol, aspirin, and drugs (some pass easily thru mucosa)
|
|
Mucosa makes (____) gastric juice/day
|
3L (.76 gallon)
|
|
How are the gastric secretions stimulated?
|
by Vagus nerve (parasym.) - increase gland activity.
|
|
What role does the sympathetic nervous system play in gastric secretions?
|
decreases gland secretion
|
|
What is the stomach lining composed of?
|
simple columnar epithelium - are goblet cells.
|
|
In the stomach lining, what do the goblet cells produce?
|
protective alkaline mucus
|
|
-leads to gastric glands
-produce gastric juice -lined w/ goblet cells |
the millions of gastric pits in the stomach lining.
|
|
What do glands in the cardiac and pylorus secrete?
|
mucus
|
|
What do glands in pyloric antrum secrete?
|
mucus and the hormone gastrin
|
|
What do glands in the fundus and body (are larger) secrete?
|
mucus, HCl, enzymes, gastrin - this is where most digestion occurs.
|
|
produce acidic mucus
|
mucous neck cells
|
|
-look like fuzzy pitch forks
|
parietal cells
|
|
secrete HCl acid and intrinsic factor IF
|
parietal cells
|
|
Responsible for extreme acidity (pH 1.5-3.5) of stomach
-activates pepsin -Denatures proteins -breaks down cell wall of plant foods -kills many bacteria |
parietal cells
|
|
What do chief cells do?
|
secrete: pepsinogen (inactive)-->pepsin (active)-->digests proteins.
|
|
What do the enteroendocrine cells secrete?
|
-Gastrin
-serotonin -histamine -somatostatin |
|
-increases gastric gland activity esp. HCl production
-increases intestinal motility (segmentation and peristalsis) -relaxes iliocecal valve -stimulates mass movements |
Gastrin secreted from enteroendocrine cells
|
|
causes contraction of smooth muscle
|
Serotonin secreted from enteroendocrine cells
|
|
activates parietal cells
|
histamine secreted from enteroendocrine cells
|
|
-inhibits gastric secretion
-inhibits gastric motility -inhibits GI blood flow and absorption -inhibits gall bladder and pancreatic activity |
Somatostatin secreted from enteroendocrine cells.
|
|
Where does the enteroendocrine cells secrete their compounds to?
|
into the Lamina Propria-->blood system-->digestive organs
|
|
The stomach epithelium is (____)
|
protected by mucus barrier and replaced every 3-6 days as cells are frequently damaged - acid and enzymes are corrosive.
|
|
Name the three phases of gastric secretion
|
1. Cephalic (reflex) phase
2. Gastric Phase 3. Intestinal Phase |
|
Occurs before food enters stomach
|
Cephalic (reflex) Phase
|
|
What is the cephalic (reflex) stage triggered by?
|
aroma, taste, sight, or thought of food.
|
|
Give the run thru of how the aroma or taste of food triggers the cephalic phase?
|
Gustatory and olfactor receptors-->impulses-->Hypothalamus-->Vagal nuclei of medulla-->vagus nerve-->Stimulate stomach glands
|
|
phase of gastric secretion that lasts 3-4 hours
|
gastric phase
|
|
-provides 2/3 gastric juice
|
gastric phase
|
|
what stimuli trigger the gastric phase of gastric secretion?
|
1. Distention-activates stretch receptors-->vagus
2. Peptides and low acidity - activates enteroendocrine cells |
|
has an excitatory and inhibitory phase
|
Intestinal phase
|
|
Describe the excitatory phase of the Intestinal phase of gastric secretion.
|
As chyme enters duodenum, mucosa of intestine releases intestinal gastrin which stimulates gastric glands.
|
|
During the excitatory phase, chyme enters duodenum and mucosa of intestine releases?
What does this do? |
-intestinal gastrin
-stimulates gastric glands |
|
Describe the inhibitory phase of the Intestinal phase of gastric secretion.
|
as duodenum distends the enterogastric reflex is triggered, this puts the brakes on the system.
|
|
What does the inhibitory phase of the intestinal phase of gastric secretion do?
|
-Inhibits the Vagus which slows down the parasympathetic NS.
-Activates the Sympathetic system: --Pyloric sphincter tightens --Decrease food entry into duodenum --Gastric secretion decreases |
|
What really finishes off digestion?
|
the Pancreas
|
|
At the end of the inhibitory phase of the intestinal phase of gastric secretion, what is released? Why?
|
-Secretin
-Cholecystokinin (CCK) -Vasoactive Intestinal Peptide (VIP) --All inhibit gastric secretion |
|
-inhibits gastric secretion
-stimulates alkaline pancreatic juice production -stimulates liver to produce bile |
Secretin
|
|
-Stimulates enzyme rich pancreatic juice production
-Stimulates contraction of the gall bladder |
Cholecystokinin (CCK)
|
|
-Dilates intestinal capillaries
-Inhibit HCl production |
-Vasoactive Intestinal Peptide (VIP)
|
|
Peristalsis begins at (____)
|
cardiac sphincter-small ripples-as descend get more powerful
|
|
During the Gastric contractile activity, the fundus is?
|
undisturbed
|
|
During the Gastric contractile activity, the contents in the pylorus are?
|
heavily mixed
|
|
Each peristaltic wave at pylorus squirts (1). These waves occur (2) times/min.
|
1. 3 mls of chyme into duodenum
2. 3 times/minute |
|
The peristaltic wave at the pylorus' rhythm is set by pacemaker cells in (1), called (2).
|
1. longitudinal smooth muscle
2. Interstitial cells of Cajal |
|
How does the Interstitial cells of Cajal generate the rhythm needed?
|
generate subthreshold depolarization waves. Neural and hormonal factors bring wave to threshold - action potential.
|
|
-Stomach empties (1) after meal
-Fluids move thru (2) -Solids move thru (3) -Fatty meals stay in stomach longer as fats digested slowly in (4) |
1. 4 hrs.
2. faster 3. slower 4. duodenum causing a "back up" |
|
Major digestive organ
|
Small intestine
|
|
Longest part of alimentary canal.
Dimensions? |
Small intestine
-20 ft. long -1 in. diameter |
|
the small intestine is divided into what three parts?
|
duodenum-->jejunum-->ileum
|
|
the pancrease sits in the?
|
curvature of the duodenum
|
|
~10 inches long
-curves around head of pancreas |
Duodenum
|
|
bile duct and pancreatic duct unite at?
|
hepatopancreatic ampulla in wall of duodenum
|
|
entry of fluids in duodenum controlled by?
|
hepatopancreatic sphincter or Sphincter of Oddi
|
|
~8 ft. long
-coiled in lower abdominal cavity -suspended by mesentery |
Jejunum
|
|
~12 ft long
-coiled -suspended by mesentery |
Ileum
|
|
The ileum joins large intestine at?
|
ileocecal valve
|
|
3 structural modifications increase surface area to maximize absorption. What are they?
|
1. Plicae circularis - circular folds - deep permanent folds of mucosa and submucosa - is a folded spiral of mucosa
2. villi - finger-like projections of mucosa - 1 mm high. 3. microvilli - tiny projections on epithelial cells of villi - brush border |
|
The epithelial cells of the small intestine are (____).
|
enterocytes
|
|
absorptive columnar cells - contain digestive enzymes.
|
enterocytes
|
|
At the core of villus there is a (____).
|
dense capillary bed and lymph capillary or lacteal. Food products enter capillary or lacteal.
|
|
Between villi are pits leading to (1), which (2). Deep in crypts are (3), and they (4).
|
1. Intestinal crypts of Lieberkuhn
2. secrete intestinal juice 3. Paneth cells 4. release lysozyme (antibacterial enzyme) |
|
Epithelium of villi are replaced every (1), cells are rapidly dividing and are targeted by (2).
|
1. 3-6 days
2. drugs of chemotherapy - nausea, vomiting, diarrhea |
|
The submucosa contains aggregated lymphoid tissue called (1), and they tend to (2).
|
1. Peyer's Patches
2. increase in numbers toward end of small intestine. |
|
How much intestinal juice is produced each day?
|
1-2L/day
|
|
production of intestinal juice is stimulated by?
|
distension of intestinal mucosa by acidic chyme.
|
|
Intestinal juice is composed of?
|
-mostly water
-some mucus -few enzymes (enzymes located in brush border) |
|
detoxifier of the body
|
liver
|
|
function of the liver
|
to make bile and export it to the duodenum (via gall bladder)
|
|
what is the largest gland in the body?
|
liver
|
|
where is the liver located?
|
under diaphragm within the rib cage
|
|
How is the liver attached?
|
to stomach via lesser omentum
|
|
the gall bladder sits in the lower recess of the?
|
liver
|
|
the liver is made up of?
|
hexagonal units - liver lobules (made of radiating plates of hepatocytes)
|
|
at corners of each lobule is a?
|
portal triad (branch of hepatic artery, branch of hepatic vein, and a bile duct)
|
|
between hepatocyte plates are?
|
liver sinusoids that empty into central vein and drains blood from liver into inferior vena cava.
|
|
inside sinusoids are hepatic macrophages called?
|
Kupffer cells.
|
|
-produce bile
-process nutrients -store glucose-glycogen -detoxifies blood |
Hepatocytes
|
|
Bile flows thru small canals called?
|
canalicule to bile ducts
|
|
blood and bile flow in?
|
opposite direction
|
|
bilirubin is broken down in small intestine by bacteria to?
|
urobilinogen (gives feces its brown color)
if no bile, feces are grey-white w/ fat streaks |
|
-small green muscular sac
-store bile and concentrates it |
gallbladder
|
|
where does the gallbladder expel bile to?
|
cystic duct which flows into bile duct
|
|
stimulus for contraction of the gallbladder is?
|
CCK
|
|
The stimulus for contraction of the gallbladder is CCK, when is it released and what else does it do?
|
-released from intestine when fatty chyme enters duodenum
-CCK also stimulates secretion of pancreatic juice. -relaxes the hepatopancreatic sphincter |
|
located below stomach
|
pancreas
|
|
produces many enzymes and secretes them into duodenum. What is this juice called?
|
pancreas
pancreatic juice |
|
the pancreatic juice flows thru (1) which fuses with (2)
|
pancreatic duct
bile duct |
|
Pancreatic secretory cells are called?
|
acini cells
|
|
what is scattered in acini cells?
|
pancreatic islets or islets of langerhans that release insulin and glucagons
|
|
how much pancreatic juice is produced by the pancreas per day?
|
1.5L of pancreatic juice/day
high pH (alkaline) helps to neutralize acidic chyme. |
|
stimultaes acini to release enzyme-rich pancreatic juice
|
CCK
|
|
-targets duct cells
-rlease of bicarbonate-rich pancreatic juice - amount produced equals amount of HCl produced in stomach. |
Secretin
|
|
Enzymes in pancreatic juice?
|
1. Trypsinogen
2. Procarboxypeptidase 3. Chymotrysinogen 4. Amylase 5. Lipase 6. Nucleases (ribonuclease and deoxyribonuclease) - Nucleic acid |
|
After trypsinogen becomes activated, what does it become?
|
Trypsin
|
|
After procarboxypeptidase becomes activated, what does it become?
|
carboxypeptidase
|
|
After chymotrysinogen becomes activated, what does it become?
|
chymotrypsin - for protein digestion
|
|
Amylase is used for?
|
Starch
|
|
Lipase is used for?
|
Fats
|
|
What regulates pancreatic secretion?
|
-parasympathetic nervous system
-intestinal hormones --secretin --cholecystokinin (cck) |
|
in the small intestine digestion begins with (____) which throughly mixes chymw w/ bile, pancreatic and intestinal juices.
|
sementation
|
|
pacemakers in duodenum depolarize (1), and in the ileum (2).
|
1. 12-14 times/min
2. 8-9 times/min |
|
(____) occurs only after nutrients are absorbed.
|
peristalsis
|
|
(____) co-ordinate by enteric neurons
|
Intestinal contraction
|
|
-from ileocecal valve to anus
|
large intestine
|
|
Major function of the large intestine.
|
absorb water and expel indigestible waste
|
|
small fat-filled pouches of visceral peritoneum in large intestine
|
epiploic appendages
|
|
longitudinal muscle layer in large intestine
|
teniae coli
|
|
longitudinal muscle layer is reduced to 3 bands - cause wall to pucker into sacs or (____).
|
haustra
|
|
subdivisions of large intestine
|
cecum, colon, rectum
|
|
blind pouch - attached is appendix
|
cecum
|
|
segments of colon
|
-ascending
-transverse -desceding -sigmoid |
|
3 transvers folds or rectal valves resulting in 3 curves
|
rectum
|
|
-last part of GI tract
-3 cm long -opens to body exterior as anus -has 2 sphincters (internal anal sphincter, involuntary smooth muscle and external anal sphincter, voluntary skeletal muscle |
anal canal
|
|
-simple columnar epithelia secreting mucus for lubrication
-no circular folds -no villi -no enzymatic excretion -mucosa is thicker |
anatomy of large intestine
|
|
-no teniae coli
-no haustra |
anatomy of rectum
|
|
In (___) bacteria ferment some of indigestible carbohydrates releasing gases: dimethyl sulfide, H2, N2, CH4, CO2 - ~500 mls/day
|
Large intestine
|
|
Describe the motility of the large intestine.
|
-mass movements are long and powerful
-peristaltic waves in colon 3-4 times/day - force feces towards rectume |
|
defecation reflex occurs when?
|
rectal wall stretched by fecal contents
|
|
describe what happens when the defecation reflex occurs.
|
-wall of sigmoid colon and rectum contract
-anal sphincters relax -feces forced into anal canal |
|
opening of (____) is voluntary and can be delayed.
|
external anal sphincter
|
|
The urge to defecate occurs w/ each mass movement and is?
|
-eventually unavoidable
-sphincter opens -muscles of rectum contract -aided by valsalva's maneuver |
