digestive sys Flashcards
extends from the mouth to the anus through the ventral body cavity (approximately 9 m, or 30 ft.)
Alimentary canal:
teeth, tongue, salivary glands, liver, gallbladder, and pancreas.
Accessory organs:
Digestion (chemical and mechanical), ingestion, secretion, mixing and propulsion, defecation
absorbtion
Role in metabolic processes
catabolism and anabolism
:Larger molecules are broken into smaller molecules (mouth, stomach, duodenum).
◦ In the GI tract, this is called ____ and can occur by either mechanical or chemical means.
catabolism. Digestion
: Smaller molecules are used as building blocks for larger molecules (liver).
anabolism
all Movements that facilitate catabolic processes
Mastication
Mixing
◦ Increase contact of food with digestive chemicals
mechanical digestion
Swallowing
Peristalsis
◦ Movement of muscles within the GI tract that facilitates movement of food
other movements
:breaking large molecule into smaller ones, mainly through hydrolysis.
Fats -> fatty acids and glycerol.
Carbohydrates: polysaccharides -> monosaccharides.
Proteins-> polypeptides -> amino acids.
Requires ____
Chemical digestion. specific enzymes
Four layers of tissues of GI tract
Mucosa (deepest), Submucosa, Muscularis Serosa/adventitia (superficial)
lumen is the inside of the tube.
mucous membrane
moucosa
(mouth, pharynx, esophagus, anus)
Epithelial tissue
Stratified squamous
(stomach and intestines)
Epithelial tissue
Simple columnar
Includes glandular cells that secrete mucus and fluid into the lumen
mucosa
Mucosa
Areolar connective tissue
(lamina propria.)
Mucosa
Smooth muscle
(muscularis mucosae)
Lamina propria contains _____, mucosa-associated lymphatic tissue that protect against disease.
“MALT”
creates folds in the lining of the stomach and small intestines
Muscularis mucosae:
irregular connective tissue that binds the mucosa to the muscularis.
blood and lymphatic vessels (to receive absorbed substances)
submucosal plexus: a network of neurons
Submucosa
mouth, pharynx, superior and middle parts of the esophagus, and anal sphincter contain skeletal muscle.
* Rest of the tract: smooth muscle
* Inner circular sheet
* Outer longitudinal sheets,
* myenteric nerve plexus between them.
Muscularis:
is the outermost layer
Serosa/adventitia
- fibrous connective tissue attached to surrounding tissues (e.g. esophagus).
adventitia
- fibrous connective tissue in the peritoneal cavity, with a mesothelium surface layer
serosa
Serosa covers the intra-abdominal organs as the
visceral peritoneum
the body’s largest serous membrane, wraps
around most abdominopelvic organs
Peritoneum
the serosa of the alimentary canal and covers other intra- abdominal organs.
visceral peritoneum
the abdominal wall, connects to visceral peritoneum.
Parietal peritoneum
five major peritoneal folds that bind the organs to one another and to the cavity walls
◦ greater omentum
◦ falciform ligament
◦ lesser omentum
◦ mesentery
◦ mesocolon
largest peritoneal fold.
* Connects the stomach to the transverse colon
* Drapes over the transverse colon and the anterior coils of the small intestine
Greater omentum :
____Contains: lymph nodes and a large amount of adipose tissue that can greatly expand
Greater omentum
attaches the liver to the anterior abdominal wall
and diaphragm.
Falciform ligament:
suspends the stomach and duodenum from the inferior edge of the liver.
pathway for blood vessels to enter the liver
contains the common bile duct.
Lesser omentum:
______ (small) and _____ (large): attach intestine to posterior abdominal wall
Mesentery. Mesocolon
(Loose/ Tight) attachment so muscular contractions can mix and move the contents along the GI tract
loose
_____ organs are covered by visceral peritoneum only on their anterior surfaces. The portion of the organ that lies behind the peritoneum is said to be “xxx”
Retroperitoneal
Organs in the retroperitoneal space include:
The kidneys and ureters
Most of the pancreas
The adrenal glands
The aorta and inferior vena cava
Digestive activities are controlled in three overlapping phases:
- The cephalic phase
- The gastric phase
- The intestinal phase
_____ :smell, sight, thought, or initial taste of food
* neural centers in the CNS to ___ for digestion.
stimulate secretion of saliva and gastric juice
cephalic phase. prepare.
:food enters the stomach.
Nervous and endocrine systems, ____ is a key hormone
Promotes secretion of gastric juice and gastric motility.
Gastric phase. gastrin
:acidic food enters the small intestine.
Neural response decreases gastric motility
Hormones (____) increases intestinal secretions and decreases gastric secretions and motility
Intestinal phase. secretin, CCK
: formed by the cheeks, hard and soft palates, and the tongue
oral or buccal cavity
mastication (chewing)
Saliva
◦ mixes with food to soften it so it can be easily swallowed
mechanical digestion
after mechanical digestion, starts the process of _____.
◦ _____: salivary amylase
◦ Fats: lingual lipase active in acidic stomach (limited activity)
Chemical digestion. Carbohydrates
Salivary regulation is under the control of the
ANS
promotes secretion
◦ This is enhanced by the cephalic phase
parasympathetic stimulation
decreases saliva secretions.
Sympathetic stimulation
located in sockets of the mandible and maxillae
teeth or dentes
- a dense fibrous connective tissue that anchors the teeth
Periodontal ligament
three major external regions of the mouth : the
crown, root, and neck
The neck of each tooth is covered by the____ , or gums, which extend slightly into each socket
gingivae
calcified connective tissue that forms most of the
tooth
dentin
harder-than-bone calcified non-living material, covers the crown
enamel
provides nutrition
pulp
___ dentitions as a child
___ as an adult
- 32
The _____:
Moves food in the mouth for chewing and swallowing
(deglutition)
Provides a sense of taste
composed of _____
the tongue. skeletal muscle