digestive Flashcards
function of digestive system: Consumption of solid or liquid food
usually through the mouth. Mastication is chewing.
Ingestion and
Mastication
the movement of food from one end of
the digestive tract to the other.
propulsion
the movement of food back and
forth in the digestive tract
mixing
the movement of food from one end of
the digestive tract to the other and the movement of food back and
forth in the digestive tract, which incorporates the digestive system’s many
secretions into the food.
propulsion and mixing
Digestion is the breakdown of large
organic molecules into smaller
molecules. Secretion is the addition of
liquid, enzymes and mucus to the
ingested food. Digestion occurs through
mechanical and chemical.
digestion and secretion
Movement of molecules out of the
digestive tract into the blood or lymphatic
system.
absorption
the breakdown of large
organic molecules into smaller
molecules
digestion
the addition of
liquid, enzymes and mucus to the
ingested food
secretion
Removal of the undigested material
such as fiber from food, and other waste
products from the body as feces
elimination
The digestive system consists of the
digestive tract or gastrointestinal tract plus associated organs
-Serous membrane that lines the Peritoneal cavity
peritoneum
The digestive tract consists of four major tunics, or
layers:
(1) the mucosa, (2) the submucosa, (3) the
muscularis, and (4) a serosa or an adventitia
the innermost tunic
mucosa
3 layers of mucosa
1.Mucous epithelium
2.Lamina propria
3.Muscularis mucosae
3 layers of mucosa: the innermost layer
mucous epithelium
3 layers of mucosa: which is loose connective tissue
lamina propria
3 layers of mucosa: thin outer layer of smooth muscle.
muscularis mucosae
lies just outside the mucosa
submucosa
Blood and lymphatic
vessels and plexus
submucosa
Circular smooth muscle
muscularis (inner)
Longitudinal smooth muscle
muscularis (outer layer)
the serosa on each side of the tube fuses
together to form a suspensory structure
mesentery
Many of the organs of the abdominal cavity are held in place by
connective tissue sheets called
mesenteries
General term referring to serous membranes attached to the
abdominal organs.
MESENTERY
Associated with small
intestine
Mesentery Proper
connects the lesser
curvature of the stomach to the liver and
diaphragm
Lesser Omentum
connects the greater
curvature of the stomach to the transverse colon
and posterior body wall
Greater Omentum
The oral cavity, or mouth, is divided into two regions:
: (1) space between the lips or cheeks and the teeth (2) oral cavity proper
which lies inside the teeth and houses the tongue
The lips and
cheeks are important in
the process of
mastication. The
tongue is a large
muscular organ that
occupies most of the
oral cavity.
Lips, cheeks and
tongue
the teeth of an adult is called Secondary/Permanent (32) and the
childhood teeth is called primary /deciduous (20).
Teeth
the teeth of an adult is called
Secondary/Permanent (32)
childhood teeth is called
primary /deciduous (20)
large
muscular organ that
occupies most of the
oral cavity.
tongue
There are ___ teeth in the normal adult mouth
32
The third molars are called
wisdom tooth
The bulk of the tooth is formed by living cellular calcified tissue called
dentin
The dentin is covered by ____ in the crown region.
enamel
The ______ contains
pulp which consist of blood vessels
pulp cavity
Each teach is held in place within
pockets in the bone called _____
alveoli
alveoli are covered by
gingiva/gums
protects the tooth against abrasion and acids produced by bacteria
enamel
helps anchor the tooth in the jaw
cementum
forms the roof of the oral cavity that
separates the oral from nasal cavity
palate
palate consist of 2 parts
hard and soft palate
anterior part that contains the
bone
hard palate
posterior parts and contains
skeletal muscle and connective tissue. Uvula is
the posterior extension of the soft plate.
soft palate
the posterior extension of the soft plate.
uvula
located in the lateral posterior walls of the
oral cavity, in the nasopharynx, and in the posterior surface of the tongue.
tonsil
produce saliva and regulated primarily by Autonomic
nervous system with parasympathetic stimulation
Salivary Glands
Salivary glands
produce
saliva
is a mixture of serous (watery) and
mucous fluids and has multiple roles
saliva
The largest of the salivary glands
parotid glands
serous gland
located just anterior to each ear.
Parotid ducts enter the oral cavity
through the 2nd upper molar
parotid glands
inflammation of the parotid gland caused by a viral
infection.
mumps
located below
the mandible. Produce more serous
than mucous secretions
submandibular
smallest gland
and produce mainly mucous
secretions
sublingual glands
composed of fluid and proteins and has three main functions
saliva
3 main functions of saliva
(1) keeps oral cavity moist
(2) protective functions (lysozyme antibacterial enzyme, neutralizes mouth ph
(3)begins the process of digestion – 5 % of total carbohydrates.
The normal daily rate of saliva secretion varies from approximately
0.5 – 1.5 L daily
saliva is a mixture of
(1)serous (watery)
(2) mucous fluids – contains
mucin that is stimulated
by sympathetic
breaks down starch
Salivary amylase
in which food is crushed and mixed with saliva to
form a bolus for swallowing
Increases efficiency of digestion
mastication
primarily cut and tear food
incisors and canines
primarily crush and grind food
premolars and molars
-connects the mouth to the
esophagus
pharynx
pharynx consist of three parts
(1)nasopharynx (2)oropharynx and
(3)laryngopharynx
only
the ____ and ____ carry food to the esophagus.
oropharynx and laryngopharynx
-moist stratified squamous epithelium, that extends from the pharynx to the stomach. It is
approx. 25 cm long and lies anterior to the vertebrae and posterior to the trachea
esophagus
esophagus is __ cm long
25 cm
swallowing is also called
deglutition
Swallowing, or deglutition (dee-glue-TISH-un), can be divided into three
phases:
(1) the voluntary phase, (2) the pharyngeal phase, and (3) the
esophageal phase
The stomach is divided into four regions
(1) cardiac part, (2) fundus, (3)
body, and (4) pyloric part
a muscular hollow organ which temporarily stores ingested food and
continue the process of mechanical digestion. Made up of simple columnar epithelium. It
has a ‘J’ shape, and features a lesser and greater curvature
stomach
produce a churning action in
the stomach.
muscularis layer
folds in the
stomach
rugae
semifluid mixture of food and gastric secretions
chyme
The muscularis layer of the stomach is different from other regions of
the digestive tract in that it consists of three layers
(1) an outer
longitudinal layer, (2) a middle circular layer, and (3) an inner oblique layer
Hormones release by the stomach ( Gastrin) and intestine help regulate the ___
gastric secretion
Stomach secretions (2 L) of the Gastric glands include four substances.
- Hydrochloric acid
- Pepsin
- Mucus
- Intrinsic factor
kills microorganism and activates the enzyme,
pepsin (produced by ____)
Hydrochloric acid ; parietal cells
______ (inactive form is pepsinogen) breaks covalent bond of proteins
to from smaller peptide chains (produced by _____)
pepsin ; chief cells
____ lubricates the epithelial cells of the stomach wall ( produced by ______)
mucus ; mucous
neck cells & surface mucous cells
____ binds with vit b12 and makes its more readily absorbed
in the small intestine (produced by ____)
intrinsic factor ; parietal cells
Approximately ___ of gastric secretions (gastric juice) are produced each
day.
2L
regulated by :
1. Nervous (CNS reflex– medulla oblongata and Local reflex – enteric plexus in
the wall of GT)
2. Hormonal mechanism (hormones produced by stomach and small intestine)
The neural mechanisms involve
central nervous system (CNS) reflexes
integrated within the medulla oblongata.
Hormonal mechanism
hormones produced by stomach and small intestine
Regulation of stomach secretions can be divided into three phases:
the cephalic phase, (2) the gastric phase, and (3) the intestinal phase.
brain phase of the stomach
secretions.
cephalic phase
can be viewed as the “get started” phase, when the stomach
secretions are increased in anticipation of incoming food.
cephalic phase
produces the greatest
volume of gastric secretions.
Activated by the presence of
food in the stomach.
gastric phase
“go for it,
” phase, when most of the stimulation of secretion
occurs.
gastric phase
the “slow down” phase, during which
stomach secretion decreases.
intestinal phase
inhibits gastric secretions. of food
in the stomach. It is controlled by
the entrance of acidic chyme into
the duodenum, which initiates
both neural and hormonal
mechanisms
Intestinal Phase
Two types of stomach movement aid digestion and help move chyme
through the digestive tract
(1) mixing waves and (2) peristaltic waves
The contractions of the stomach occur about every ___ seconds and proceed
from the body of the stomach toward the pyloric sphincter
20
weak contractions
Mixing waves
strong
contractions
peristaltic waves
major function is absorption of nutrient. It is about 6 m long and consist of three parts.
small intestine
small intestine is about ____ long
6 m
small intestine consists of
(1) the duodenum, (2) the jejunum, and (3) the ileum
smallest section (25 cm long)
- described as a C-shaped located
below the stomach that surrounds
the pancreas
duodenum
Receives stomach chyme,
pancreatic juice and bile from liver
and gallbladder via duodenal
ligament. (cholecystokinin and
secretin hormone)
duodenum
-The ____ marks the division
between the duodenum and the
jejunum
suspensory muscle of
duodenum
-2.5 m long that absorb sugars,
amino acids, and fatty acids.
jejunum
-longest part (3.5 m long)
It absorbs any final nutrients, with major
absorptive products being vitamin B12 and
bile acids.
ileum
jejunum is ___ long
2.5 m
how long is the ileum
3.5 m
small aggregates
of lymphatic tissue found in the
mucosa of the ileum.
Peyer’s patches
The small intestine has three
modifications that increase its
surface area about___-fold.
600
small intestine: The mucosa and submucosa form a
series of ____ that run
perpendicular to the long axis of the
digestive tract.
circular folds
small intestine: Tiny, fingerlike projections of the
mucosa form numerous ____, which
are 0.5–1.5 mm long
villi
Each villus is covered by simple
columnar epithelium. numerous
cytoplasmic extensions,
called ___
microvilli
small intestine, secretions from the mucosa Contains mainly
mucus (duodenal glands and goblet cells), ion and water
Most of the intestinal secretions entering the small intestine is produced by the
_______ with addition from the secretions of liver and pancreas
intestinal mucosa
produce digestive enzymes and absorb digested food.
Absorptive cells.
produce protective mucus
Goblet cells
help protect intestinal epithelium from bacteria
granular cells
produce regulatory hormones
Endocrine cells
The epithelial cells in the intestinal walls produce two major enzyme groups
(1) peptidases and (2) disaccharidases
digest
proteins. They break the peptide bonds in proteins to form amino acids.
Peptidases
disaccharides to
monosaccharides
disaccharides
proceed along
the length of the intestine for variable
distances and cause the chyme to move
along the small intestine
-Peristaltic contractions
are
propagated for only short distances and
mix intestinal contents
-Segmental contractions
The largest internal organ and weights about ____ kg
liver , 1.36 kg
takes oxygen rich blood to the liver
Hepatic artery
carries blood that is oxygen poor but rich in absorbed nutrients
and other substances form digestive tract
Hepatic portal vein
Blood exit through the hepatic vein
Hepatic vein
The right and left lobes are separated by a connective
tissue septum, called the
falciform (FAL-si-form) ligament
processes nutrient and
detoxifies harmful substances form
the blood.
liver
The liver produce and secretes about
______ L of bile each day.
600 -1000 L
complex alkaline solutions
that contain bile salts, bile
pigments (BILIRUBIN), cholesterol,
lipids, lipid soluble hormone, and
lecithin( mixture of
phospholipids).
bile
can remove sugar from the blood and store it as glycogen
liver
retroperitoneal and posterior to the stomach
pancreas
composed of both endocrine and
exocrine tissues
pancreas
pancreatic
islets, or islets of Langerhans that
produce the hormone insulin and
glucagon.
endocrine
composed of acinar
glands. Acini cells produce
digestive enzymes that empties
into the pancreatic duct
exocrine
EXOCRINE - composed of acinar
glands. ____ produce
digestive enzymes that empties
into the pancreatic duct
Acini cells
function of pancreas
neutralize the acidic chyme that enters the
small intestine from the stomach.
The major protein digesting enzyme (PROTEOLYTIC)
(1)Trypsin
(2)chymotrypsin and (3) carboxypeptidase.
continue the polysaccharide digestion that began in the
oral cavity.
Pancreatic amylase
lipid digesting enzyme
lipase
degrade DNA and RNA into nucleotides.
Nucleases
extends from ileocecal junction to the anus. Absorbs water and converted into feces.
large intestines
process of elimination of feces
defecation
large intestine, small pouches of the
peritoneum filled with fat
omental appendices
large intestine, are saccules in the colon
that give it its segmented
appearance.
haustra
large intestine, small pouches of the peritoneum
filled with fat and situated along the
colon and upper part of the rectum
teniae coli
large intestine consists of four parts:
(1) cecum, (2) colon, (3) rectum, and (4) anal canal.
proximal end of the
large intestines where it joins
the small intestine in the
ileocecal junction. Located on
the right lower quadrant of the
abdomen. Attached to the
cecum is the appendix.
cecum
Attached to the
cecum is the
appendix
approximately 1.5 –
1.8 m long and can be divided
into four parts: ascending,
transverse, descending and
sigmoid (terminal portion). The
mucosal lining of the colon is
crypts, which contains many
mucous producing goblet cells.
colon
how long is a colon
approximately 1.5 –
1.8 m long
colon can be divided
into four parts:
ascending,
transverse, descending and
sigmoid (terminal portion).
The
mucosal lining of the colon is
___, which contains many
mucous producing ____ cells.
crypts, goblet cells
straight muscular
tube that begins in the
termination of sigmoid colon
and anal canal. The muscular
tunic is composed od smooth
muscle and is relatively thick
in the rectum compared to the
rest of the digestive tract.
rectum
the last 2-3
cm of digestive tract. Begins
at the inferior end of rectum
and ends at the anal canal
anal canal
