NU 545 - Exam 6 Study Guide 2023-2024 Latest
Update
1. ANATOMY OF GI SYSTEM Anatomy and function of the GI
system components; normal intestinal flora. (P.1393-97, 1400,
1409) - ANSWER-The digestive system breaks down ingested
food, prepares it for uptake by the body's cells, provides body
water, and eliminates wastes.
The functions of the GI system are ingestion of food; propulsion of
food and wastes from mouth to anus; secretion of mucus, water,
and enzymes; mechanical digestion of food particles; chemical
digestion of food particles; absorption of digested food; and
elimination of waste products by defecation. Consists of GI tract
and accessory organs—liver, gallbladder, and exocrine pancreas.
(P. 1393) The GI tract consists of mouth, esophagus, stomach,
small intestine, large intestines, rectum, and anus. Has 4 layers of
tissue: mucosa, submucosa, muscularis, and serosa/adventitia
(esophagus).
Enteric nervous system within GI tract controlled by local and
autonomic nervous system—3 nerve plexus: submucosal plexus,
myenteric plexus, and subserosal plexus.
(P. 1395) Mouth - ANSWER-reservoir for chewing and mixing
food with saliva. 3 pairs salivary glands (submandibular,
sublingual, and parotid).
The esophagus and Stomach - ANSWER-A hollow muscular tube
that controls swallowing substances from oropharynx to stomach.
Each end of the esophagus has a sphincter: cricopharyngeal
muscle and cardiac sphincter. (P. 1397)
, NU 545 - Exam 6 Study Guide 2023-2024 Latest
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The stomach is a hollow muscular organ that stores food during
eating, secretes digestive juices, mixes food with juices, and
propels partially digested food (chyme) into the duodenum of
small intestine.
(P. 1400) The small intestine - ANSWER-is about 5 to 6 m long
and is functionally divided into three segments: the duodenum,
jejunum, and ileum. The duodenum essential role in mixing food
with digestive juices from the liver and pancreas. The jejunum and
ileum facilitate intestinal motility and support blood vessels,
nerves, and lymphatics. The peritoneum is the serous membrane
surrounding the organs of the abdomen and lining the
abdominopelvic cavity.
A central lacteal, or lymphatic capillary is contained within each
villus and is important for the absorption & transport of fat
molecules. A person who has problems with lacteals will have
alterations in fat absorption. Digested fats move into the lacteals
and eventually reach the liver through the systemic circulation.
(P. 1408) The large intestine - ANSWER-is approximately 1.5 m
long and consists of the cecum, appendix, colon, rectum, and
anal canal. The cecum is a pouch that receives chyme from the
ileum. Attached to the cecum is the vermiform appendix, has little
or no physiologic function. From the cecum, chyme enters the
colon, four-parts that descends to the anal canal: ascending
colon, transverse colon, descending colon, and sigmoid colon.
Most of the water is absorbed in the colon by diffusion and active
, NU 545 - Exam 6 Study Guide 2023-2024 Latest
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transport. By the time the fecal mass enters the sigmoid colon,
the mass consists entirely of wastes and is called the feces. The
gastrocolic reflex initiates propulsion in the entire colon, usually
during or immediately after eating, when chyme enters from the
ileum. This reflex causes the fecal mass to pass rapidly into the
sigmoid colon and rectum, stimulating defecation (rectosphincteric
reflex). Defecation is facilitated by squatting or sitting because
these positions straighten the angle between the rectum and anal
canal and increase the efficiency of straining.
(P.1409) Bacteria from stomach to distal colon. Stomach is
relatively sterile due to acid production. Bile acid secretion,
intestinal motility, and antibody production suppress bacterial
growth in the duodenum, and in the duodenum and jejunum there
is a low concentration of aerobes: streptococci, lactobacilli,
staphylococci, enterobacteria, and Bacteroides. Anaerobes are
found distal to ileocecal valve and consists 95% of fecal flora and
1/3 of the solid bulk of feces: Bacteroides, clostridia, anaerobic
lactobacilli, and coliforms are the most common microorganisms
from the ileum to the cecum.
(P. 1409) The liver, gallbladder, and exocrine pancreas -
ANSWER-all secrete substances necessary for the digestion of
chyme. These secretions are delivered to the duodenum through
ducts. The liver produces bile, which contains salts necessary for
fat digestion and absorption. Between meals bile is stored in the
gallbladder. The exocrine pancreas produces enzymes needed
for the complete digestion of carbohydrates, proteins, and fats.
The exocrine pancreas also produces an alkaline fluid that
, NU 545 - Exam 6 Study Guide 2023-2024 Latest
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neutralizes chyme, creating a duodenal pH that supports
enzymatic action. The liver receives nutrients absorbed by the
small intestine and metabolizes or synthesizes these nutrients
into forms that can be absorbed by the body's cells. It then
releases the nutrients into the bloodstream or stores them for later
use.
Kupffer cells (macrophages) in the sinusoids of the liver remove
bacteria and foreign particles from blood in the hepatic circulation.
ANKYLOSING SPONDYLITIS Know Ankylosing spondylitis:
pathophysiology, etiology, prevention, clinical manifestations,
diagnostics, treatment and complications (pg. 1572-1574) -
ANSWER-is the most common of a group of inflammatory
arthropathies known as spondyloarthropathies. It is a chronic
inflammatory joint disease characterized by stiffening and fusion
(ankylosis) of the spine and sacroiliac joints.
Patho: The exact cause of AS is unknown but its high association
with the histocompatibility antigen human leukocyte antigen
(HLAB27) has been known for decades. New research has shown
that misfolding of HLA-B27 occurs in the endoplasmic reticulum
(ER). As misfolded proteins accumulate, it results in a stress
response of the ER and increased production of interleukin-23 (IL-
23), a potent cytokine that may also act on T-helper 17 cells,
promoting their survival. Th17 cells, in turn, produce the
inflammatory cytokine. In AS, the primary pathological problem is
uncontrolled bone formation rather than bone destruction seen
with most other types of arthritis. The end results of AS are
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