Summary Food
for life
Period 4
GZW
2023-2024
,Case 1
Intestinal tract
Anatomy
The intestinal tract, or gastrointestinal tract, or
digestive tract, is a long tubue-like structure
from mouth to the anus, through the body.
Main sections are (devided in food intake
phase:
Cephalic phase (related to head: chewing,
mixing, salive. Also seeing, smelling, ect: body
gets ready for food):
- Mouth:
o Mechanical breaking down door
by chewing and mixing with
saliva which contains enzymes
that begin the breakdown
process of carbohydrates (CHO).
It is made in salivary
glands underneath the
tongue (Sublingual
gland), other glands are:
Parotoid gland
Submandibular
gland
o Saliva functions are
digestion, absorption,
protection and lubrication
1500 mL
- Esophagus;
o Tube with muscles that is connected to the stomach, it uses peristalsis
to push food downwards
o Walls of oesophagus are similar to the duodenum: mucosa / lamina
propia / musculair mucosa / submucosa / muscle layer (inner and
outer) / secosa
o Between the mouth and oesophagus is an oesophical sfinxter
>> Gateric phase: purpose is storage, mixing, digestion, barrier function
- Stomach;
o The organ that stores and mixes food with gastric juices, which contains
enzymes and hydrochloric acid to breakdown proteins and kill
bacteria. It also secretes mucus to protect
itself to the stomach acid
o 3 sections
(Cardia: enter point after sfinxer into
the stomach)
Fundus: uppermost portion
Body / corpus: the central and
largest part
, (Enterum: Between body and pylorus)
Pylorus: lowermost portion, between body and duodenum. It
contains the phyloric sphincter which is a muscular valve that
regulates passage of partially digested food (chyme) into the
small intestine
o Stomach has a sfinxer
>> Intestinal phase, function is to digest, absorb, mix and for transportation.
- Small intestine: longest part of the digestive tract and majority of digestion
and nutrient absorption happens here.
o Duodenum: receives the partially digested food from the stomach with
digestive juices from the pancreas and bile from the liver further
breakdown of f ood
Proximal part of small intestine (duodenum and start jejenum) is
primarily involved in the absorption
Gallbladder and liver empties in the duodenum
Has picae
circulares, they increase the surface 600 times
o Jejenum: middle part, mostly absorption of nutrients. Has smaller
diameter, and less picae
o Ileum: absorption of remaining nutrients, vitamins and bile acid
- Colon / large intestine: shorter but wider than the small intestine. ‘Good’
bacteria, or probiotics, in the colon, which digest nondigestible
carbohydrates, as fibers
o Ascending colon: right ride, going upward. It absorbs water and
electrolytes from food residue and begin the process of feces forming
o Transverse colon: horizontal from right to left side. Continues the
process of water absorption and electrolytes, also compacting the
feces.
o Descending colon: left side going downwards. Here also absorption of
water and electrolytes
o Sigmoid colon: between descending colon and rectum, characterized
by its S-shaped curve. Serves as storage for feces, but is also involved
in absorption of water and electrolytes from the feces
o Rectum: storage of feces until it is ready to be expelled from the body
via the canalis analis (anus), and has 2 sfinxters
The organs which are also involved in the digestion, but the eaten food is not going
through:
- Pancreas: exocrine functions are the pancreatic juices for further breakdown
of food with lipase, amylase, trypsin, ect. Endocrine function (islets of
, Langerhans) produce glucagon (alfa-cells), insulin (beta-cells) and
somatostatin (D-cells), and pancreatic polypeptide (PP-cells)
- Liver: produces bile for further breakdown of fat, next to this a lot of other
functions:
o Defradation and exretion waste products, detoxification of poisonous
substances, glycogen storages, glucose production (gluconeogenesis),
protein production and breakdown, cholesterol production, iron storage,
ext
o Has vena portae from intestine to liver) and ductus hepaticus
(galwegen van galblaas en lever)
- Gallbladder: stores bile, which is
produced in the liver. Release bile
into duodenum via
hepatopancreatic duct.
The 4 layers of the intestinal wall
- Mucosa: innermost layer of intestinal
lining (inclusive the stomach),
composed of a single layer of
epithelial cells. Also contains
glands/globet cells, which secretes
mucus, gastric acid (stomach) and
digestive enzymes (stomach). Also
has enterocytes which absorbs
nutrients.
This layer also absorbs nutrient and
water
- Submucosa: lies beneath the mucosa and consists of connective tissue,
containing blood vessels, lymphatic vessels and nerves. It provides structural
support and facilitates transport of absorbed nutrients and fluid
- Muscularis externa: smooth muscle tissue in 3 layers: inner oblique layer,
middle circular layer, and outer longitudinal layer. Contraction and
relaxation facilitate
mechanical digestion with
mixing food with gastric
juices and propelling chyme
through the digestive tract,
the peristaltic contractions
move food through the
digestive tract.
- Serosa: outer layer of
stomach, with a thin
protective membrane of
connective tissue. It anchors
the stomach to surrounding tissues and provides lubrication to reduce friction.
The epithelial surface has millions of small villi, these are important in absorption of
nutrients and increases the absorptive area by 10 times.
Motility
Spontaneous contractions are around 12x / min
, Migrating myoelectric complex (MMC) is around every 1,5 hour, they ‘clean’ the
intestines and prevent bacterial reflexes
2 ways:
- Segmentation
o Contraction on random places, when there is food spilt in 2 1 part
is pushed forward, other pushed backwards
- Peristalsis
o Push food forward, because of contraction right after the food mush
for life
Period 4
GZW
2023-2024
,Case 1
Intestinal tract
Anatomy
The intestinal tract, or gastrointestinal tract, or
digestive tract, is a long tubue-like structure
from mouth to the anus, through the body.
Main sections are (devided in food intake
phase:
Cephalic phase (related to head: chewing,
mixing, salive. Also seeing, smelling, ect: body
gets ready for food):
- Mouth:
o Mechanical breaking down door
by chewing and mixing with
saliva which contains enzymes
that begin the breakdown
process of carbohydrates (CHO).
It is made in salivary
glands underneath the
tongue (Sublingual
gland), other glands are:
Parotoid gland
Submandibular
gland
o Saliva functions are
digestion, absorption,
protection and lubrication
1500 mL
- Esophagus;
o Tube with muscles that is connected to the stomach, it uses peristalsis
to push food downwards
o Walls of oesophagus are similar to the duodenum: mucosa / lamina
propia / musculair mucosa / submucosa / muscle layer (inner and
outer) / secosa
o Between the mouth and oesophagus is an oesophical sfinxter
>> Gateric phase: purpose is storage, mixing, digestion, barrier function
- Stomach;
o The organ that stores and mixes food with gastric juices, which contains
enzymes and hydrochloric acid to breakdown proteins and kill
bacteria. It also secretes mucus to protect
itself to the stomach acid
o 3 sections
(Cardia: enter point after sfinxer into
the stomach)
Fundus: uppermost portion
Body / corpus: the central and
largest part
, (Enterum: Between body and pylorus)
Pylorus: lowermost portion, between body and duodenum. It
contains the phyloric sphincter which is a muscular valve that
regulates passage of partially digested food (chyme) into the
small intestine
o Stomach has a sfinxer
>> Intestinal phase, function is to digest, absorb, mix and for transportation.
- Small intestine: longest part of the digestive tract and majority of digestion
and nutrient absorption happens here.
o Duodenum: receives the partially digested food from the stomach with
digestive juices from the pancreas and bile from the liver further
breakdown of f ood
Proximal part of small intestine (duodenum and start jejenum) is
primarily involved in the absorption
Gallbladder and liver empties in the duodenum
Has picae
circulares, they increase the surface 600 times
o Jejenum: middle part, mostly absorption of nutrients. Has smaller
diameter, and less picae
o Ileum: absorption of remaining nutrients, vitamins and bile acid
- Colon / large intestine: shorter but wider than the small intestine. ‘Good’
bacteria, or probiotics, in the colon, which digest nondigestible
carbohydrates, as fibers
o Ascending colon: right ride, going upward. It absorbs water and
electrolytes from food residue and begin the process of feces forming
o Transverse colon: horizontal from right to left side. Continues the
process of water absorption and electrolytes, also compacting the
feces.
o Descending colon: left side going downwards. Here also absorption of
water and electrolytes
o Sigmoid colon: between descending colon and rectum, characterized
by its S-shaped curve. Serves as storage for feces, but is also involved
in absorption of water and electrolytes from the feces
o Rectum: storage of feces until it is ready to be expelled from the body
via the canalis analis (anus), and has 2 sfinxters
The organs which are also involved in the digestion, but the eaten food is not going
through:
- Pancreas: exocrine functions are the pancreatic juices for further breakdown
of food with lipase, amylase, trypsin, ect. Endocrine function (islets of
, Langerhans) produce glucagon (alfa-cells), insulin (beta-cells) and
somatostatin (D-cells), and pancreatic polypeptide (PP-cells)
- Liver: produces bile for further breakdown of fat, next to this a lot of other
functions:
o Defradation and exretion waste products, detoxification of poisonous
substances, glycogen storages, glucose production (gluconeogenesis),
protein production and breakdown, cholesterol production, iron storage,
ext
o Has vena portae from intestine to liver) and ductus hepaticus
(galwegen van galblaas en lever)
- Gallbladder: stores bile, which is
produced in the liver. Release bile
into duodenum via
hepatopancreatic duct.
The 4 layers of the intestinal wall
- Mucosa: innermost layer of intestinal
lining (inclusive the stomach),
composed of a single layer of
epithelial cells. Also contains
glands/globet cells, which secretes
mucus, gastric acid (stomach) and
digestive enzymes (stomach). Also
has enterocytes which absorbs
nutrients.
This layer also absorbs nutrient and
water
- Submucosa: lies beneath the mucosa and consists of connective tissue,
containing blood vessels, lymphatic vessels and nerves. It provides structural
support and facilitates transport of absorbed nutrients and fluid
- Muscularis externa: smooth muscle tissue in 3 layers: inner oblique layer,
middle circular layer, and outer longitudinal layer. Contraction and
relaxation facilitate
mechanical digestion with
mixing food with gastric
juices and propelling chyme
through the digestive tract,
the peristaltic contractions
move food through the
digestive tract.
- Serosa: outer layer of
stomach, with a thin
protective membrane of
connective tissue. It anchors
the stomach to surrounding tissues and provides lubrication to reduce friction.
The epithelial surface has millions of small villi, these are important in absorption of
nutrients and increases the absorptive area by 10 times.
Motility
Spontaneous contractions are around 12x / min
, Migrating myoelectric complex (MMC) is around every 1,5 hour, they ‘clean’ the
intestines and prevent bacterial reflexes
2 ways:
- Segmentation
o Contraction on random places, when there is food spilt in 2 1 part
is pushed forward, other pushed backwards
- Peristalsis
o Push food forward, because of contraction right after the food mush
