Digestive Flashcards
Functions of digestive system
Ingestion and mastication
Propulsion and mixing
Digestion and secretion
Absorption
Elimination
Consumption of solid or liquid food usually through the mouth.
Ingestion
chewing
Mastication
the movement of food form
one end of the digestive tract to the other.
Propulsion
the movement of food back and
forth in the digestive tract.
Mixing
is the breakdown of large
organic molecules into smaller
molecules.
Digestion
the addition of
liquid, enzymes and mucus to the ingested food.
Secretion
Digestion occurs through
Mechanical anc chemical
Removal of the undigested material such as fiber from food, and other waste
products from the body as feces
Elimination
Movement of molecules out of the digestive tract into the blood or lymphatic
system.
Absorption
Consist digestive/gastrointestinal tract and associated organs
Anatomy of digestive system
Serous membrane that lines the Peritoneal cavity
Peritoneum
TUNICS/LAYERS OF THE GI TRACT
Serosa
Muscularis (outer layer)
Muscularis (inner layer)
Submucosa
Mucosa
Mesentry
Visceral peritoneum / adventitia
Serosa
Longitudinal smooth muscle
Muscularis (outer layter)
Circular smooth muscle
Muscularis (inner layer)
Blood and lymphatic
vessels and plexus
submucosa
Types of mucosa
1.Mucous epithelium
2.Lamina propria
3.Muscularis mucosae
the serosa on each side of the tube fuses together to form a suspensory structure
Mesentry
the serosa on each side of the tube fuses
together to form a
Suspensory structure
General term referring to serous membranes attached to the
abdominal organs.
Mesentry
Types of mesentry
Mesentry proper
Lesser omentum
Greater omentum
Associated with small
intestine
Mesentry 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
Oral cavity divided into 2 regions
1) space between the lips or cheeks and the teeth (2) oral cavity proper
which lies inside the teeth and houses the tongue
important in
the process of
mastication.
Lips and cheeks
large
muscular organ that
occupies most of the
oral cavity
Tongue
the teeth of an adult is called
Secondary/Permanent (32)
Childhood teeth
primary /deciduous (20)
The bulk of the tooth is formed by living cellular calcified tissue called
Dentin
The dentin is covered by ___ in the crown region.
enamel
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
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.
Soft palate
the posterior extension of the soft plate
Uvula
produce saliva and regulated primarily by Autonomic
nervous system with parasympathetic stimulation.
salivary glands
Salivary gland has
Parotid gland
Submandibular
Sublingual glands
serous gland
located just anterior to each ear.
Parotid glands
enter the oral cavity
through the 2nd upper molar
Parotid ducts
located below
the mandible. Produce more serous than mucous secretions
Submandibular
smallest gland
and produce mainly mucous
secretions
Sublingual glands
Salivia daily
0.5 - 1.5 L
Saliva is a mixture of
Serous (watery)
Mucous fluids
contains mucin that is stimulated
by sympathetic
Mucous fluids
which food is crushed and mixed with saliva to form a bolus for swallowing Increases efficiency of digestion
Mastication or chewing
connects the mouth to the
esophagus.
Pharynx
Thre parts of pharynx
Oropharynx
Nasopharynx
Laryngopharynx
moist stratified squamous epithelium, that extends from the pharynx to the stomach.
Esophagus
25 cm long and lies anterior to the vertebrae and posterior to the trachea
Esophagus
muscular hollow organ which temporarily stores ingested food and
continue the process of mechanical digestion.
Stomach
Made up of simple columnar epithelium. It
has a ‘J’ shape, and features a lesser and greater curvature.
Stomach
The stomach has four major
regions:
cardia, fundus, body, and pylorus.
produce a churning action in
the stomach.
Muscularis layer
semifluid mixture of food and gastric secretions
Chyme
Stomach secretions (2 L) of the Gastric glands include four substances.
Hydrochloric acid
Pepsin
Mucus
Intrinsic factor
Inactive form of pepsin
Pepsinogen
kills microorganism and activates the enzyme,
pepsin (produced by parietal cells)
Hydrochloric acid
breaks covalent bond of proteins
to from smaller peptide chains (produced by chief cells)
Pepsim
lubricates the epithelial cells of the stomach wall (mucous
neck cells & surface mucous cells)
Mucus
binds with vit b12 and makes its more readily absorbed
in the small intestine (produced by parietal cells)
Intrinsic factor
hormones produced by stomach and small intestine
Hormone mechanisms
Nervous
CNS reflex– medulla oblongata and Local reflex – enteric plexus in
the wall of GT
3 phase of Stomach secretion
Cephalic phase
Gastric phase
Intestinal phase phase
brain phase of the stomach
secretions.
Cephalic phase
produces the greatest
volume of gastric secretions.
Activated by the presence of
food in the stomach.
Gastric 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
Movement in the stomach
Mixing and peristaltic wave
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
Three parts of small intestine
Duodenum
Jejunu
Ileum
smallest section (25 cm long)
- described as a C-shaped located
below the stomach that surrounds
the pancreas
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
small aggregates
of lymphatic tissue found in the
mucosa of the ileum
Peyer’s patches
The mucosa and submucosa form a series of
Circular folds
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
retroperitoneal and posterior to the stomach
Pancreas
composed of both endocrine and exocrine tissues
Pancreas