Test 1 Flashcards
The length of the GI tract in a living person
Half a cadaver’s length because of muscle tone, about 15 feet (30 in cadaver)
The ACCESSORY DIGESTIVE ORGANS include
salivary glands, pancreas & biliary system (liver & gall bladder).
The basic functions of the GI tract are to:
separate ingested food into essential nutrients & unnecessary wastes
absorb the former while getting rid of the latter
Smooth muscle in the walls of the GI tract maintains a constant low level of contractions known as
tone
Tone is important in
maintaining a steady pressure on the contents of the GI tract as well as in preventing its walls from remaining permanently stretched following distention.
3 basic types of motility:
- propulsive movements or PERISTALSIS
- mixing movements or SEGMENTATION
- TONIC CONTRACTIONS of sphincters or valves
Promotes mechanical digestion of food
Motility - SEGMENTATION
What does the mechanical digestion of food by motility Promote?
Facilitates absorption by exposing all portions of the intestinal contents to the absorbing surfaces of the GI tract
These GI checkpoints also serve to regulate the movement of luminal contents
Tonic contractions of sphincters, with intermittent relaxation,
All of the GI sphincter muscles are Completely dependent on involuntary contractions of smooth muscle except for…
The sphincters at both ends…
The early portion of the esophagus
(including the UES), and The External Anal Sphincter
regulates movement of contents of the
common bile duct into the duodenum
Sphincter of Oddi
How much Saliva Does the human body make in a typical day?
1.5 L
How much gastric juice Does the human body make in a typical day?
2.5 L
How much bile Does the human body make in a typical day?
0.5 L
How much pancreatic juice Does the human body make in a typical day?
1.5 L
How much intestinal secretion Does the human body make in a typical day?
1.0 L
How much mucus Does the human body make in a typical day?
2.0L
volume of fluid entering or secreted into the lumen of the GI tract each day
9L
From the daily 9L of fluid, approximately how much ends up in stool daily, with the balance recycled back to the body.
100 ml
The breakdown process whereby the structurally complex foodstuffs of the diet are converted into smaller absorbable units Occurs by…
mechanically via the aforementioned motility and chemically via enzymes
What quadrant is the Liver Located in?
RUQ: Right lobe
LUQ: Left Lobe
What quadrant is the Gallbladder Located in?
RUQ
What quadrant is the Stomach Located in?
RUQ: Pyloris
LUQ: the rest
What quadrant is the Spleen Located in?
ULQ
What quadrant is the Duodenum Located in?
RUQ: Parts 1/3
What quadrant is the Pancreas Located in?
RUQ: head
LUQ: body and tail
What quadrant is the Kidney+Adrenal gland Located in?
RUQ: Right
RLQ: Left
What quadrant are the colic flexures Located in?
RUQ: right hepatic fixture
ULQ: colic splenic flexure
What quadrant is the Ascending colon Located in?
URQ: superior part
LRQ: Inferior part
What quadrant is the Transverse colon Located in?
URQ: right half
ULQ: Left half
What quadrant is the Descending colon Located in?
ULQ: left half
LLQ: inferior part
What quadrant is the Cecum Located in?
RLQ
What quadrant is the Vermiform appendix Located in?
RLQ
What quadrant is most of the ileum Located in?
RLQ
What quadrant are the uterine tubes and ureters Located in?
RLQ, and LLQ
What quadrant are the ovaries Located in?
RLQ, and LLQ
What quadrant are the ovaries Located in?
RLQ, and LLQ
9 Abdominal- Pelvic Regions
RH | E | LH
RL | U | LL
RI | P | LI
Right Hypochondriac, Epigastric, Left Hypochondriac Right Lateral (Lumbar) , Umbilical, Left Lateral (Lumbar) Right Inguinal (Groin) , Pubic, Left Inguinal (Groin)
is a slick serous membrane of the abdominopelvic cavity
peritoneum
covers the external surfaces of most digestive organs and is continuous with the parietal peritoneum
visceral peritoneum
lines the walls of the abdominopelvic cavity.
parietal peritoneum
is the condition characterized by the accumulation of peritoneal fluid.
Ascites
contains large folds that weave between the viscera hangs loosely from the transverse colon and small intestine
greater omentum,
which in found in between the small intestine and anchors it to the posterior abdominal wall
mesentery
gastric juice penetrates the gastric mucosal barrier, injuring the gastric wall with its acidic and enzymatic contents.
peptic ulcer disease (PUD)
pancreatic juice escapes the pancreas and/or duodenum
acute pancreatitis
the colon wall tears open, allowing intestinal bacteria (“flora”) to escape to the abdominal and pelvic cavities, causing peritonitis or even death.
ruptured appendix
The three main layers of the Mucosa
Mucosa
Submucosa
Muscularis Externa
Serosa
The prominent type of self-induced electrical activity in digestive smooth muscle is called
slow-wave potential, or the GI’s basal electrical rhythm (BER) or pacemaker potential
The neurons of the submucosal and myenteric plexuses are often termed the intrinsic nerve plexuses or the
enteric nervous system (ENS)
Nerves that originate outside the GI tract and innervate the various GI organs –
namely, nerve fibers from both branches of the autonomic nervous system
Extrinsic Nerves
Structures that the vagus nerves innervates in the upper GI tract:
- esophagus
- stomach
- small intestine
- ascending colon
The vagus nerves are mixed nerves in
which____% of the fibers are afferent
and____% are efferent.
75%
25%
What are the things the pelvic nerves (pelvic splanchnic) innervate in the lower GI tract:
• transverse, descending & sigmoid
colons
• anal canal
What are the The pelvic nerves derive from spinal nerve pairs that innervate the Transverse, descending and sigmoid colon, and the anal canal
S2, S3 and S4.
The majority of parasympathetic, post-ganglionic neruons servicing the GI system are
cholinergic; some are peptidergic (VIP, enkephalins, neuropeptide Y, substance P)
These post-ganglionic fibers are adrenergic and these sympathetic ganglia serve the GI tract:
- celiac
- superior mesenteric
- inferior mesenteric
The principal glands of salivation are the…
Parotid
Submandibular
Sublingual
Glands
dry mouth and infection / inflammation of the buccal mucosa.
XEROSTOMIA
everal diseases affect the salivary glands resulting in xerostomia. These diseases include
Sjögren’s syndrome, HIV/AIDS, diabetes, and Parkinson’s disease.
An autoimmune disease were the mucous membranes and moisture-secreting glands of your eyes and mouth are usually affected first — resulting in decreased tears and saliva.
Sjögren’s syndrome
In a Salivary Gland The acinus is comprised of a central lumen surrounded by pyramidal-shaped cells. Each acinus is surrounded by a layer of
myoepithelial cells
Parotid Acinar type, viscosity, and Percentage of Whole Unstimulated Daily Saliva
Serum, watery, 25%
Submandibular Acinar type, viscosity, and Percentage of Whole Unstimulated Daily Saliva
Mixed, semi viscus, 71%
Sublingual
Mucus, viscus, 3-4%
Drains the parotid gland…
Stensen’s duct
Drains the submandibular gland
Wharton’s duct
Drains the sublingual gland
Ducts of Rivinus
mix with water to become mucus, which
lubricates food
mucins
hydrolyzes internal α-1,4 linkages only.
Salivary α-amylase
Salivary α-amylase does not cleave…
terminal α-1,4 linkages or α-1,6 linkages
antibacterial component of saliva attacks bacterial cell walls
lysozyme
Found in saliva chelates iron, preventing the
multiplication of organisms that require it for growth
lactoferrin
AB found in saliva active against
certain viruses and bacteria
immunoglobulin A (IgA)
Teeth start to demineralize at what pH?
< 5.5 approximately
The salivary glands are enervated by which CNs?
the parasympathetic nervous system via CN VII, and CN IX
The sympathetic nervous system enervates the salivary glands via…
T1-T3
we can distinguish How many chemicals tasting?
4000-10,000
However, behavioral evidence suggests that these discriminations represent only 4 or 5 primary taste qualities:
Taste receptor cells (“taste cells”) are located within clusters of cells known as…
Taste buds
Taste buds are generally found on…
PAPILLAE located over the tongue, palate, pharynx and epiglottis.
- Mushroom-like
- Scattered over entire tongue surface, but most abundant at its tip and along its anterior sides
- Mainly respond to sweet & salty substances but also to sour
Fungiform Papillae
- Folded structures
- Most abundant on the middle edges of the tongue
- Mainly respond to sour
Foliate Papillae
• Largest and least
numerous; form an inverted “V” at the back of the tongue
• Respond mostly to bitter substances
Circumvallate
The taste buds on the circumvallate papillae & some of the foliate papillae are innervated by the…
glossopharyngeal nerve (CN IX)
The taste buds on fungiform papillae and some of the foliate papillae are innervated by the…
chorda tympani branch of the facial nerve (CN VII)
Taste buds in the region of the epiglottis are supplied by the…
vagus nerve (CN X)
Taste buds in the region of the palate are supplied by the…
facial nerve (CN VII)
is a branch of the mandibular division of the trigeminal nerve which supplies sensory innervation to the tongue. It also carries fibers from the facial nerve, which return taste information from the anterior two thirds of the tongue.
The lingual nerve
contains the gustatory nuclei
nucleus of the solitary tract (NST) or solitary nucleus located in the brainstem
The muscles of mastication receive their motor innervation from the mandibular division of the…
Trigeminal Nerve (CN-3)
Name the Muscles of Mastication
Masseter Temporalis Medial Pterygoid Lateral Pterygoid
jaw nears closure; strongest forces are exerted; represents the longest component of the cycle
Occlusal
unlike the rest of the GI tract, the esophagus has no…
true serosal outer layer, but is covered by a thin and poorly defined layer of connective tissue
in cases of portal hypertension (an increase in pressure in the portal vein, usually due to cirrhosis)
lower esophagus may enlarge into ESOPHAGEAL VARICES
Various agents have been showed to decrease LES pressure, which in turn, decreases it’s closing strength. This permits reflux of acidic gastric contents into the esophagus This diseases is called…
GERD - gastroesophageal reflux disease
If swallowing is painful, it is referred to as …
odynophagia
difficulty in swallowing
dysphagia
is characterized by a repair process in which the squamous mucosa that normally lines the esophagus is gradually replaced by columnar epithelium (metaplasia) resembling that in the stomach and intestines.
Barrett’s esophagus
is associated with increased risk of developing esophageal cancer.
play an important role in protecting the stomach mucosa from injury by enhancing mucus production.
Prostaglandins
secrete HCl & intrinsic factor (IF)
Parietal cells
secrete pepsinogen & gastric lipase
Chief cells
stimulates gastric juice secretion
when food is being chewed in the mouth or with the
sight, smell, or thought of food
Vagus nerve weakly stimulates
• Vagus nerve weakly stimulates gastric juice secretion
when food is being chewed in the mouth or with the
sight, smell, or thought of food
• Vagus nerve stimulates gastrin secretion from the
enteroendocrine cells of the gastric glands
• Gastrin further stimulates secretion of gastric juice
CEPHALIC PHASE
• Begins when food reaches the stomach
• Distention of the stomach and protein digestion
products (amino acids) stimulate gastrin secretion
and hence more gastric juice secretion – this
represents a positive feedback loop •
Vagus nerve also continues to stimulate gastrin
release and gastric motility
• Elevated levels of gastrin stimulate the release of
histamine, which in turn increases HCl secretion
from parietal cells
GASTRIC PHASE
Small amounts of acidic chyme enter the duodenum which stimulates the secretion of 3 hormones that inhibit gastric juice secretion:
• cholecystokinin (CCK)
• secretin
• gastric inhibitory peptide (GIP) GIP also inhibits gastric motility
INTESTINAL PHASE
H. pylori survives in the stomach because it produces…
the enzyme urease, which generates substances (namely NH neutralize the stomach’s acid and enable the bacteria to survive
Inadequate absorption of vitamin B12 causes?
pernicious anemia
vomiting can also be caused by signals arising in areas of the brain. This is particularly true for an area located bilaterally on the floor of the 4th ventricle called the
chemoreceptor trigger zone.