Digestive System Flashcards
What controls the rate in which the stomach is emptying?
Pyloric sphincter
What must happen to nutrients?
They must be broken down into smaller components before body can make use of them
What does the digestive system act as?
A disassembly line
What does the digestive system do?
To break down nutrients into forms that can be used by the body
To absorb them so they can be distributed to the tissues
____ is the study of the digestive tract and the diagnosis and treatment of its disorders
Gastroenterology
What is the digestive system ?
organ system that processes food, extracts nutrients, and eliminates residue
What are the 5 stages of digestion?
Injestion, digestion, absorption, compaction, exceretion (defecation)
Digestion is ______
the mechanical and chemical breakdown of food molecules into a form usable by the body
_________ is the uptake of nutrient molecules into the epithelial cells of the digestive tract and then into the blood and lymph
Absorption
____ is the absorbing water and consolidating the indigestible residue into feces
Compaction
____ is the physical breakdown of food into smaller particles
Mechanical digestion
What are 2 examples of mechanical digestion?
Cutting and grinding action of the teeth
Churning action of stomach and small intestines
____ is a series of hydrolysis reactions that breaks dietary macromolecules into their individual monomers
Chemical digestion
Where are digestive enzymes produced?
In salivary glands, stomach, pancreas and small intenstine
Polysaccharides (carbohydrates) are broken down to ____, proteins to ________, lipids to ____ and nucleic acids to _________
Glucose
Amino acids
Monoglycerides and fatty acids
Nucleotides
____ is the muscular contractions that break up and propel food through the canal, mix it with digestive enzymes and eliminates the waste
Motility
____ is the release of digestive enzymes and hormones that carry out or regulate digestion
Secretion
____ is the release of digestive enzymes and hormones that carry out or regulate digestion
Secretion
____ is active transport and facilitated diffusion that absorb nutrients and transfer them to the blood and lymph
Membrane transport
What are the 2 main divisons of the digestive tract?
Digestive tract and accessory organs
What is the digestive tract also called?
Alimentary canal
What are the accessory organs?
Teeth, tongue, salivary glands, liver, gallbladder, and pancreas
What are the tissue layers of the GI tract?
Mucosa, submucosa, muscularis externa and serosa
The epithelium, lamina propria, muscularis mucosae and MALT make up the ______
Mucosa
What makes up the submucosa?
Blood and lymphatic vessels, nerve plexus and glands
What is the muscularis externa composed of ?
Inner circular layer
Outer longitudinal layer
The serosa is the ______
Areolar tissue or mesothelium
What are the 2 nerve networks of the enteric nervous control?
Submucosal and myenteric plexus
The ________ controls glandular secretion of mucosa
Controls movement (contractions) of muscularis mucosae and is found in the submucosa
Submucosal plexus
What NS contriols peristalis?
Myenteric plexus
____________ is a serous membrane that lines the peritoneal cavity of the abdomen and covers the mesenteries and viscera.
Peritoneum
What do the lesser and greater omentum do?
Lesser - attaches stomach to liver
Greater - covers small intestines like an apron
What does the mesentery of small intestine do?
holds many blood vessels
What does the mesocolon do?
anchors colon to posterior body wall
The motility and secretion of the digestive tract are controlled by ______, ______, and __________.
neural, hormonal, and paracrine mechanisms.
Includes 2 automatic reflexes:
short (myenteric) reflexes: swallowing
long (vagovagal) reflexes: parasympathetic stimulation of digestive motility and secretion
neural control in the regulation of the digestive tract.
What are examples of hormones produced by the digestive tract?
gastrin and secretin
What are examples of paracrine secretions?
histamine and prostaglandins
What are the functions of the mouth (oral or buccal cavity)?
Ingestion (food intake)
Taste and other sensory responses to food
Mechanical digestion: chewing
Chemical digestion: begins digestion of carbohydrates and lipids
Swallowing, speech, and respiration
Lubrication: mixing with mucous and salivary gland secretions
What type of tissue lines the mouth?
Stratified squamous epithelium
What do the lingual glands in the tongue do?
secrete saliva, tonsils in root
What is the vestibule?
space between teeth and cheeks
What are the lips/labia divided into?
cutaneous area (mustache area) and red (vermillion) area (lipstick area)
How many baby/decidous teeth do people have by 2 years?
20
How many teeth do adults have?
Adult have (32): 16 in mandible and maxilla
Incisors, canines, premolars and molars
Explain each tooth.
2 incisors—central and lateral
1 canine—pointed and act to puncture and shred food
2 premolars—broad surface for crushing, shredding, and grinding
3 molars—even broader surface for crushing, shredding, and grinding
____ is sticky residue on the teeth made up of bacteria and sugars
Plaque
When is root canal therapy needed?
if cavity reaches pulp
____ is the inflammation of gums.
Gingivitis
________ is the destruction of the supporting bone around the teeth which may result in tooth loss
Periodontal disease
What is the first step of mechanical digestion?
Mastication or chewing
In chewing, the __________, ______, and manipulate food and push it between the teeth
tongue, buccinator and orbicularis oris
In chewing, the masseter and temporalis _____
Elevate the teeth to crush food
What swings the teeth in side-to-side grinding action of molars?
medial and lateral pterygoids
What are some functions of saliva?
moistens the mouth
begins starch and fat digestion
cleanse teeth
inhibit bacteria
moistens food and binds it together into bolus
Is saliva hypertonic or hypotonic?
Hypotonic
What does salivary amylase do?
enzyme that begins starch digestion
What is lingual lipase?
enzyme that digests fat after it reaches the stomach (activated by stomach acid)
What does mucus do?
binds and lubricates a mass of food and aids in swallowing
What is lysozyme?
an enzyme that kills bacteria
What is immunoglobin A?
an antibody that inhibits bacterial growth