Lecture 18 -- review questions Flashcards
what are the major organs of the digestive system?
oral cavity (mouth)
pharynx
esophagus
stomach
small intestine
large intestine
what are the accessory organs of the digestive system?
teeth
tongue
salivary glands
liver
gallbladder
pancreas
what is another name for the alimentary canal?
digestive tract
–> muscular hollow that food passes thru from mouth to anus
what are the 4 layers of the organs of the digestive tract?
in –> out
(1) mucosa
(2) submucosa
(3) muscularis propria
(4) adventitia/serosa
which layer is in contact with food particles?
mucosa
which organs of the digestive system have adventitia instead of serosa?
oral cavity
pharynx
esophagus
rectum
(only stomach and intestines have serosa)
the muscularis external (or propria) is situated b/n which layers?
submucosa (in) and adventitia/serosa (out)
what is the name of the nervous system found in the walls of the digest systems organs that can work independently of the CNS?
enteric NS
what is a plexus?
network of nerves
what 2 plexuses form part of the enteric NS?
submucosal/meissner’s plexus
myenteric/auerbach’s plexus
what is another name for the submucosal plexus?
meissner’s plexus
in which layer is the submucosal (meissner’s) plexus located?
submucosa
what is the primary function of the submucosal plexus?
GI secretions
blood flow
what is another name for the myenteric plexus?
Auerbach’s plexus
in which layer is the myenteric plexus located?
muscularis propria (b/n the circular and longitudinal layers of muscularis)
which is the primary function of the myenteric plexus?
peristalsis
GI movement function
what is the main difference b/n short and long reflexes w/in organs of the GI tract?
short (myenteric) –> stimulus only from w/in enteric NS w/in GI tract
long –> stimulus involves CNS integration centers outside GI tract
which autonomic NS subdivision, parasympathetic or sympathetic, stimulate GI activity (motility and secretions)?
thru which cranial nerve?
stimulate motility and secretions –> “rest and digest”
parasympathetic
vagus nerve
which autonomic NS subdivision, parasympathetic or sympathetic, inhibit GI activity (motility and secretions)?
inhibit GI activity
sympathetic
smelling or seeing yummy food will stimulate the secretion of saliva;
which kind of reflex will be involved here: short or long reflexes?
which autonomic NS subdivision?
long
parasympathetic
what is peristalsis?
alternating waves of smooth muscle contraction
results in propulsion (movement) of materials thru GI tract
in which organs of the digestive system does peristalsis occur?
esophagus, stomach, small/large intestines
what is segmentation?
moving materials back and forth –> help mix undigested materials w/ intestinal secretions
no net movement
helps digest and absorb chemicals
in which organs fo the digestive system does segmentation occur?
intestines
which type of GI motility will help with the propulsion (movement) of food particles thru the GI tract: peristalsis or segmentation?
persitalsis
which type of GI motility will most help to mix food particles with GI secretions: peristalsis or segmentation?
segmentation
can you use segmentation to move food particles thru your esophagus toward your stomach?
no –> only peristalsis
what is ingestion?
selective intake of food (thru oral cavity)
what is digestion?
mechanical (physical) and chemical (by digestive enzymes) breakdown of food into a form usable by the body
thru which process is mechanical digestion performed in your mouth? and in your small intestine?
chewing (mouth)
churching (stomach)
segmentation (small intestine)
what is the physiological process of “propulsion”?
movement of food particles
swallowing (oropharynx)
peristalsis (esophagus, stomach, intestines)
what is absorption?
nutrient molecules –> epithelial cells of the digestive tract –> blood or lymph
what does compaction mean?
absorbing water and consolidating the indigestible residue into feces
what is defecation?
elimination of feces
what are the 4 types of teeth?
incisor
canine
premolar
molar
label the picture w/ the name of the tooth and indicate the number of roots it contains
green –> incisor –> 1 root
blue –> canine –> 1 root
yellow –> premolar –> 1-2 roots
purple –> molar –> 2-3 roots
why are the canines also called cuspids? (think about an anatomical characteristic)
has 1 elevation (point of ‘cusp’)
which type of teeth is known as “the grinders”?
premolars
molars
what are the 3 parts of a tooth?
crown
neck
root
what substance covers the tooth’s crown? (outer layer)
enamel
what substance covers the tooth’s root?
cementum
why is enamel considered a non-living structure?
what is its composition?
its function?
hard mineralized non-living substance
consists of apatite crystals containing calcium and phosphate
outer covering of tooth’s crown
what’s dentin?
yellowish tissue that makes up bulk of all teeth
consists mainly of apatite crystals
does dentin contain cells?
no –> just consists mainly of apatite crystals
what’s the composition of dentin?
appatite crystals
where is dentin?
makes up the bulk of the teeth –> inside the outer covering
what’s the color of dentin?
yellow tissue
where is the tooth’s pulp?
innermost layer of tooth –> underneath the outer covering and underneath the dentin
what does the pulp contain?
(1) connective tissue
(2) blood
(3) lymphatic vessels
(4) nerves
(5) odontoblasts
what’s the name of the cells in the pulp that contribute to dentin formation?
odontoblasts
which part of a tooth is responsible for sensitivity to pain, pressure, and temperature? Why?
pulp –> it contains nerves
what’s the tooth’s cementum? where is it?
bone-like material
covers the roots
what’s the root canal? what does it contain?
passageway for blood vessels and nerves to the pulp
what structure in your mouth covers the cementum and root of the tooth?
periodontal ligament
what is the difference b/n major and minor salivary glands?
major –> extrinsic –> have their own large gland structures –> secrete a lot of saliva at once in response to food
minor –> intrinsic –> small gland dispersed in oral tissues that secrete saliva at constant rate in relatively small amounts
which produces the most volume of saliva when food is ingested?
major (extrinsic)
what are the 3 major salivary glands?
parotid
submandibular
sublingual
what’s saliva?
water-mucus mixture that:
- moistens and cleanses the mouth
- dissolves molecules so they can better spread on taste buds
- make swallowing easier by binding teh food particles into a soft mass (bolus) and lubricating it with mucus
which 2 components of saliva help fight bacteria?
lysozyme
IgA
what’s lysozyme?
an enzyme in saliva that helps kill bacteria
which 2 saliva enzymes start the chemical digestion of carbohydrates (starch) and lipids?
carbohydrates (starch) –> amylase
lipids –> lipase
what is called bolus?
mouth chews food into a ball that is lubricated with mucus
which 2 structures does the esophagus connect?
pharynx and stomach
what are the names of the 2 sphincters of the esophagus?
upper esophageal sphincter
lower esophageal (cardiac) sphincter
where is the upper esophageal sphincter?
connects pharynx w/ upper part of esophagus
where is the lower esophageal sphincter?
connects lower part of esophagus w/ stomach
what’s the primary function of the upper esophageal sphincter?
protects against reflux of food into airways
prevents entry of air into digestive tract
what’s the primary function of the lower esophageal sphincter?
protects esophagus from reflux of gastric contents
what is the lower esophageal sphincter also called?
cardiac sphincter
where is the swallowing center?
medulla
what is the name of the 3 phases of the swallowing mechanism? why these names? (think about bolus location)
(1) oral (or buccal)
(2) pharyngeal phase
(3) esophageal phase
what prevents food from being aspirated? during which phase?
epiglottis blocks food from entering trachea
pharyngeal phase
how is the bolus pushed down thru the esophagus?
peristalsis
why is it essential to close the cardiac sphincter once the bolus reaches the stomach?
prevent regurgitation of gastric contents back into esophagus
which phase of the swallowing process can you “voluntarily” control? (think about where you have skeletal muscle)
oral (or buccal) phase
