digestive system Flashcards
what does the digestive system consist of
GI tract and accessory organs
what is the pathway for food, break down into nutrients and packaging of waste products
GI tract
what includes accessory organs that aid in mastication and glandular secretions that air in enzymatic digestion
accessory organs
what we ingest is called
food
whats the substance that provides nourishment essential for growth and maintaining life
nutrients
what is it the process of breakdown of food via mechanical and chemical means called
digestion
oral cavity-> _______
duodeunum of gi tract
what is the process by which nutrients are absorbed into bloodstream
absorption
jejnum-> _____
colon
what are the 6 essential activities of digestive system
- ingestion
- propulsion
- mechanical digestion
- chemical digestion
- absorption
- defecation
intake of solid food and drink via oral cavity
ingestion
what is mastications
chew food, involing teeth and tongue
mechanical break down is
ingestion
what is peristalsis
propulsion
what kind of movement is propulsion
downward movement of food
what does the food in propulsion go through
GI tract
how long does propulsion take
24-36 hours
deglutition is
swallowing
what is deglutition and peristaltic waves mean
wave of contraction and relaxation
what is mechanical digestion also called
segmentation
mixing of food with digestion secretions via musclar contraction is called
mechanical digestion
mechanical digestion has alternate what
forward and back movement of GI contents
where is mechanical digestion seen
in small and large intestines
chemical digestions uses what
enzymes
what is the breakdown into smaller molecules for easier digestion
chemical digestion
what is the movement of molecules from digestive tract and into blood or lymph
absorption
what are waste products of digestion that are eliminated by the body
defacation
where does defecations predominately occur
large intestine
how many layers does digestive system have
4
what are the four layers of DS
mucosa, submucosa, muscularis externa, serosa
where do the layers span from in the digestive system
esophagus to anus of GI tract
what is the innermost tunic
mucosa
what are the 2 types of epithelium in mucosa
lamina propria
muscularis mucosae
where is nonkeratinized stratified squamous epithelium found (4)
mouth
oropharynx
esophagus
anus
what kind of epi is the remained of Gi tract
simple columnar epi
what layer has thick CT
submucosa
what layer has nerves, B’s, lymph vessels and small glands
submucosa
what layer is inner with circular smooth muscle and outer longtidinal smooth muscle
muscularis
what does the upper esophagus contain
skeletal muscle
stomach has 3rd layer which =
oblique
what is the outermost tunic
serosa (adventitia)
outermost tunic is also called
visceral peritoneum
adventitia =
CT in esophagus and retroperitoneal organs
fold size for esophagus
smallest:
medium:
large:
none x3
fold side for stomach
smallest:
medium:
largest:
microvilli
pits
rugae
fold side for small intestine
smallest:
medium:
largest:
microvilli
villi
circular folds
fold side for large intestine
smallest:
medium:
largest:
microvilli
pits
haustra
the digestive system has local control of what
enteric nervous system
the nervous regulation of DS has extensive network of
neural tissue
what does the nervous regulation consists of
submucosal plexus and myenteric plexus
what innervates smooth muscle of the gut, controls local secretion, absorption and muscle movements in the nervous regulation
submucosal
what is found between circular and longitudinal smooth muscle layers, along entire GI tract, increases tone of gut and velocity and intensity of contractions
myenteric
what does the nervous regulation control
peristalsis and mixing, blood flow in GI tract
what is a painful developmental disorder due to lacking a subset of enteric neurons in distal large intestine
hirshsprung disease
hirshsprung disease is a mutation in what gene
RET
what does the RET gene usually do
encodes a receptor normally activated by growth factors required for survival and differentiation of enteric neuron subset
what do mutations of the RET gene lead to
loss of enteric neurons-> poor intestinal motility and severe constipation
true or false: newborns can have abdominal distension and no BM within 48 hours after birth
true
is the vomting in hirshprung
yes
is hirschsprung more common in male or female
male
what is hirschprings associated with
inherited conditions
what happens in hirshsprungs
difficulty passing stool (at birth), as bowel does not relax, stool builds up-> bowel obstruction
how do u diagnose hirshsprungs
rectal biopsy
abdominal xray
anal manometry
what do u see in rectal biopsy w megacolon
absence of ganglion cells
what do you see in abdomonal xray with megacolon
swollen then narrow
what do you see with anal manometry with megacolon
rectal ballon inflated, muscles should relax, if not= megacolon
what is the treatment for megacolon (5)
surgical bypass or removal of colon portion that lacks nerve cells
high fiber food
increased fluids
physical activity
laxative
what are complications of megacolon
susceptible to serious intestinal infection
what is susceptible to serious intestinal infection called
enterocolitis
is enterocolitis life threatening
yes
how many NT are associated with ens
30
what stimultes digestive tract motility and secretions
Ach
what inhibits digestive tract motility and secretions
NE
what stimulates digestive tract motility
serotonin
chemotherapy affects digestive activity which can result in
nausea
what blocks serotonin receptors and alleviates nausea
ondansetron
digestive hormones, paracrine chemicals (histamine) effect on nearby cells effect what
effects pH levels
what is the serous membrane sheet covering walls and adominal cavity organs
peritoneum
what secretes serous fluid
smooth membrane
what is serous fluid
a lubricant seen between membrne layers
membrane and fluid reduces what? as the organs move in abdomen
friction
fold with outer layer =
parietal peritoneum
inner layer=
visceral peritoneum
what is life threatening inflammation of peritoneum
peritonitis
what is peritonitis due to
chemical irritation
S&S of peritonitis
acute abdominal pain
tenderness (worse w movement)
what is accumulation of xs serous fluid in pertoneal
ascites
ascites is also seen with what?
starvation, alcoholism, different cancers (liver, ovarian)
true or false: in ascited fluid does not reaccumulate based on cause
false
what is a continuous, double layer of epithelial tissue attached to posterior abdominal wall
mesentery
what does the mesentery hold in place
all digestive organs in abdominal cavity
where does the mesentery connect
to one another and to the posterior wall
where does the mesentery extend from
junction between esophagus/ stomach to rectum
what is the attachment to the posterior wall of the mesentery called
mesenteric root
what is the mobile attaching to jenunum and ileum to posterior abdominal wall
small intestine mesentery
what is anchored to mobile to anchored
right, transverse and left mesocolon
what is anchored and mobile
mesosignmoid and mesorectum
term for lesser curve of stomach to proximal duodenum to liver and diaphragm
lesser omentum
term for greater curve of stomach to transverse colon
greater omentum
the greater omentum has what
a double fold of mesentery from stomach over small intestine
what does the greater omentum have large amounts of
adipose tissue and B&T cells
what ligament goes from liver to diaphragm
coronary ligament
what goes from liver to anterior abdominal wall
falciform
outer lining, part of the body wall
parietal peritoneum
inner lining, part of the wall of tract/ organs
visceral peritoneum
peritoneum connecting body to suspended viscera
mesentery
peritoneum between suspended viscera
omentum
