NUTRI - DIGESTIVE Flashcards
The science of nourishment. Nutrients from food must be
made available for use by the body cells. Made possible
by the digestive system (through digestion), releasing
the nutrients and converting them into molecules.
NUTRITION
- The mechanical and chemical breakdown of
complex substances into their constituent parts;
the conversion of food into smaller and simpler
units.
DIGESTION
The breakdown of food materials mechanically
(through chewing) and chemically (action of
digestive enzymes) until it is a form from which
nutrients can be absorbed from the GIT into the
blood and lymph.
DIGESTION
- Also promotes the movement of nutrients from
the gastrointestinal tract or alimentary canal into
the body through the process of absorption. - Is made up of GIT or digestive tract, the liver,
pancreas and gallbladder.
DIGESTIVE SYSTEM
is a chain of hollow organs connected in a long,
twisting tube from mouth to the anus.
GIT
Digestion begins in the ______ where food is
broken down to pieces by chewing.
MOUTH
The mucus like saliva performs three functions: MPD
- Mixes with food, lubricating dry foods and
diluting thicker foods; - Provides alpha amylase, a polysaccharide
digesting enzyme, and lingual lipase, a lipid
digesting enzyme. - Dissolves some molecules in food, allowing
them to interact with chemoreceptors in the
mouth giving rise to the taste sensation.
Transfers food from the mouth to the esophagus
and warms, moistens, and filters air before food
is moved into the trachea.
THROAT/PHARYNX
- small ball rolled composed of food that
is lubricated with saliva.
BOLUS
A muscular tube extending from the pharynx to
the stomach. Measuring about 10 inches long, it
connects the mouth to the stomach.
ESOPHAGUS
- (rhythmic contraction and
relaxation of the esophageal muscles), propelled
the bolus in the esophagus to the stomach. Also
reduces further the size of food particles and
mixes them thoroughly with digestive secretions.
PERISTALSIS
A small flap at the top of the
windpipe (trachea). Prevented the food from
entering the respiratory tract and lungs.
EPIGLOTTIS
- A sac-like organ with tough muscular walls. It
holds, mixes, and grinds food. It secretes acid
and powerful enzymes that carry on the process
of breaking down food.
Has three sets of muscles surrounding a cavity
that can expand to accommodate the ingested
food and fluid. The pH level is maintained at pH
1.5-1.7
STOMACH
responsible for
the strongly acidic condition of the
stomach. With such an environment,
ingested proteins are denatured thus
facilitating their digestion
HYDROCHLORIC ACID SECRETION
a semi liquid homogeneous mass
formed from between the esophagus
mixes and gastric secretions.
CHYME
found at the
entrance of the stomach which controls
the amount of food entering the
stomach.
CARDIAC SPHINCTER MUSCLE
A long loosely coiled tube in the abdomen which
when spread out, would be more than 20ft long.
It is the body’s longest organ. Its diameter of
about 1.5 inches is much smaller than that of the
large intestine.
SMALL INTESTINE
Small Intestine has 3 sections:
- Duodenum - continue the process of breaking
down food. - Jejunum - responsible for the absorption of
nutrients into the bloodstream. - Ileum
- Duodenum -
continue the process of breaking
down food.
- Jejunum -
responsible for the absorption of
nutrients into the bloodstream.
- ILEUM
- ILEUM
Chyme leaving the stomach bypasses the opening from
the common bile duct which receives secretions from the
gallbladder and the pancreas. Then the liquified chyme
travels down to the 3 sections of the small intestine.
Chyme leaving the stomach bypasses the opening from
the common bile duct which receives secretions from the
gallbladder and the pancreas. Then the liquified chyme
travels down to the 3 sections of the small intestine.
made in the liver and stored in the gallbladder, is
emptied into the small intestine to aid lipid digestion.
BILE
the two gastrointestinal
hormones release through the presence of chyme in the
small intestine.
SECRETIN and CHOLECYSTOKININ
Secretin and Cholecystokinin - the two gastrointestinal
hormones release through the presence of chyme in the
small intestine.
2 actions:
- Stimulate the pancreas to release its digestive
enzymes and sodium bicarbonate, an alkali that
neutralizes the acidic chyme. - Stimulate the gallbladder to contract to release
the stored bile.
- A long muscular tube, approximately 5 to 6 ft
that connects the caecum (first part of the large
intestine) to the rectum (last part of the large
intestine).
LARGE INTESTINE/COLON
5 PARTS OF LARGE INTESTINE/COLON
- Caecum
- Ascending right colon
- Transverse (across) colon
- Descending left colon
- Sigmoid colon - connected to the rectum
made up of mostly food debris and bacteria.
Normally takes about 36 hours to get through the colon
STOOL
An 8 inch chamber that connects the colon to
the anus. It receives stool from the colon and
holds it until defecation.
RECTUM
The digestive tract ends here which consists of
the pelvic floor muscles and the two anal
sphincter. The lining of the upper anus is
specialized to detect rectal contents. The pelvic
floor muscle creates an angle between the
rectum and anus that stops stool from coming
out. The anal sphincters provide control in the
elimination of stool.
ANUS
