Lecture Test #3 Flashcards
What are the functions of the digestive system?
(ASDIME)
-ingestion
-motility
-secretion
-digestion
-absorption
-elimination
What is ingestion?
Taking food into mouth
What is secretion?
Release of water, acid, buffers, and enzymes into lumen of GI tract
What is Mixing and propulsion? (Motility)
Churning and movement of food through GI tract
What is absorption?
Passage of digested products from GI tract into blood and lymph
What is digestion?
Mechanical and chemical breakdown of food
What is defecation? (Elimination)
Elimination of feces from GI tract
What do accessory organs do?
Assist with digestion
What are the main organs of digestion?
-mouth
-pharynx
-esophagus
-stomach
-small intestine
-large intestine
-rectum
-anal canal
What are the accessory organs of digestion?
-salivary glands
-tongue
-teeth
-liver
-gallbladder
-pancreas
Where is bile produced?
Liver
Where is bile stored?
Gallbladder
What are the salivary glands? (In order from superior to inferior)
-parotid glands (superior)
-sublingual glands
-submandibular glands (inferior)
How many deciduous (baby) teeth do humans have?
20
How many permanent (adult) teeth do humans have?
32
Where is the pharynx located?
Posterior walls of oropharynx and laryngopharynx
What does the pharynx do?
Contains muscles that contribute to swallowing
What does the esophagus do?
Transports food from pharynx to stomach
What is GERD?
gastroesophageal reflux disease
(Acid reflux)
What is peristalsis?
Ability to move food
What is segmentation?
Mixing and churning of food with digestive juices
What are the walls of the GI tract in order?
-serosa (outer)
-muscularis
-submucosa
-mucosa (inner)
What are the divisions of the stomach?
-fundus
-body
-pylorus
What are the sphincter muscles?
-cardiac sphincter
-pyloric sphincter
What do parietal cells produce?
HCI
What does HCI do?
-kills bacteria
-denatures proteins
-helps convert pepsinogen into pepsin
What type of cells are gastric glands composed of?
-chief cells
-endocrine cells
-parietal cells
What are the functions of the stomach?
-reservoir for food
-chemical and mechanical digestion
-secretes intrinsic factor
-produces gastrin
-protection
What is mechanical digestion?
Physical breakdown of food into smaller particles (teeth and tongue)
What is chemical digestion?
Reactions that break macromolecules into their subunits
(Enzymes from saliva, stomach, pancreas)
What are the hormones of motility?
-gastrin
-secretin
-cholecystokinin (CCK)
Where does the small intestine receive chyme from?
Stomach
Where do secretions from the liver and pancreas enter the GI tract?
Near junction of stomach and small intestine
What is important to the digestive process of the small intestine?
Secretions
What are the functions of the Liver?
-detoxification
-bile synthesis and secretion
-metabolism
-storage
-production of plasma proteins
-produces urea
-helps regulate blood cholesterol level
What are the bile ducts?
-right and left hepatic ducts
-cystic duct
-common bile duct
What is bile composed of?
-water
-bilirubin
-bile salts
-cholesterol
-bicarbonate
-electrolytes
Where does the gallbladder eject bile to?
Duodenum
What type of cells is insulin?
Beta cells
What type of cells is glucagon?
Alpha cells
Pancreatic duct
Joins the bile duct at the hepatopancreatic ampulla
Accessory pancreatic duct
Allows pancreatic juice to be released into the duodenum
Pancreatic juice
Alkaline (basic) mixture of water, enzymes, zymogens, sodium bicarbonate, electrolytes
What antagonizes glucagon?
Insulin
What does insulin stimulate?
-glucose and amino uptake by muscle
-glycogen, fat, and protein synthesis
What can absorb glucose without insulin?
-brain
-liver
-kidneys
-RBC’s
What does glucagon stimulate?
Glycogenolysis and fat catabolism
What does glucagon promote?
Absorption of amino acids by the liver for gluconeogenesis
What is gastrin released by?
The stomach
What does gastrin cause?
Release of HCI and pepsinogen
What is secretin released by?
Duodenum
What is the release of secretin stimulated by?
Acidic chyme
What does secretin do?
Stimulates the pancreas to release bicarbonate-rich fluid
What does secretin potentiate?
Cholecystokinin (CCK)
What is cholecystokinin (CCK) released by?
Duodenum
What does CCK stimulate?
-bile secretion
-pancreatic secretion of enzymes
What does CCK do?
Inhibits gastric motility and secretion
What are the small intestines in order?
- Duodenum
- Jejunum
- Ileum
How long is the duodenum?
About 10 inches
How long is the jejunum?
About 3-6 ft long
Where does most digestion and nutrient absorption occur?
Jejunum
How long is the ileum?
About 6-9 ft long
What is the purpose of segmentation?
Mix and churn, not to move material along
Where does carbohydrate digestion begin?
The mouth
Where does carbohydrate digestion end?
Small intestine
Where does protein digestion end?
Small intestine
Where does protein digestion begin?
Stomach
Where does fat digestion begin?
Small intestine
Where does fat digestion end?
Small intestine
What requires bile to be digested?
Fat
What are some primary nutrients absorbed by the stomach?
-alcohol (20%)
-water (minor amount)
What are some primary nutrients absorbed by the small intestine?
-calcium
-magnesium
-iron
-glucose
-amino acids
-fats
-vitamins
-water (70-90%)
-alcohol (80%)
What are some primary nutrients absorbed by the large intestine?
-sodium
-potassium
-fatty acids
-gases
-water (10-30%)
How much of the total amount of alcohol and water is absorbed by the stomach?
Alcohol - 20%
Water- minor amount
How much of the total amount of alcohol and water is absorbed by the small intestine?
Alcohol- 80%
Water- 70-90%
How much of the total amount of water is absorbed by the large intestine?
10-30%
What does the large intestine consist of?
-cecum
-colon
-rectum
What are the four different colons?
-ascending colon
-transverse colon
-descending colon
-sigmoid colon
Where is the appendix attached to?
Lower end of cecum
What does the bacteria that populates the large intestine do?
-helps synthesize vitamins B and K
-ferments cellulose and other undigested carbs
What does feces consist of?
75% water and 25% solids
What do the solids of feces consist of?
-30% bacteria
-30% undigested fiber
-10-20% fat
-small amount of mucous
-epithelial cells
What is defecation?
Bowl movement. Release of waste
What is constipation?
Difficult bowel movement (less than 3 a week)
What is diarrhea and what can it lead to?
Loose, watery stools. Can lead to dehydration
What are polysaccharides?
Complex carbohydrates, starch, fiber
What are 3 carbohydrates?
-polysaccharides
-disaccharides
-monosaccharides
What are 3 types of monosaccharides?
-glucose
-galactose
-fructose
Glucose
Primary source of energy
Galactose
Converted by liver to glucose
Fructose
Used by sperm, converted by liver to glucose
Glycogenesis
Formation of glycogen in liver and muscle
Glycogen in liver
Maintains blood glucose levels
Glycogen in muscle
Used by the muscle for energy
Glycogenolysis
-Glycogen is broken down to glucose
-increases blood glucose levels
Gluconeogenesis
Production of glucose from alternate sources
Lipogenesis
Production of fat from carbohydrates, proteins and fats
What is required in the diet?
Essential fatty acids
What are 3 types of lipids?
-triglycerides
-phospholipids
-cholesterol
What produces more energy: Lipid catabolism or carbohydrates
Lipid catabolism
LDL (low density lipoprotein)
-carries lipids from liver to cells
- “bad cholesterol”
HDL (high density lipoprotein)
- carries cholesterol from cells to liver for disposal
- “good cholesterol”
Protein anabolism
-most important
-structural, hormones, enzymes, transport molecules
- 8-9 essential amino acids
Protein catabolism
-energy
-protein balance
-nitrogen balance
What is protein balance?
Amount of protein ingested vs amount used
What is nitrogen balance?
Amount of nitrogen ingested vs amount excreted
Positive nitrogen balance =
Growth
Negative nitrogen balance =
Wasting
What is essential and must be obtained from diet?
Vitamins and minerals
Fat soluble
-dissolves in fat
-stored in the body
-requires bile for absorption
-possibly toxic
Water soluble
-dissolves in water
-not stored in body
-seldom toxic
What do vitamins serve as?
Coenzymes
What do minerals serve as?
Cofactor
What are minerals?
Inorganic elements or salts found in the earth
What are some examples of minerals?
-iron
-iodine
-potassium
-sodium
-calcium
Basal metabolic rate
-energy required for activities
-controlled by thyroid hormone
-higher in men than women
-decreases with age
Total metabolic rate
Combination of:
-basal metabolic rate
-energy for voluntary activities
-energy to digest food
Energy in = energy out
-energy balance
-constant weight
Energy in is greater than energy out=
-excess energy
-weight gain
Energy in is less than energy out=
-energy deficit
-weight loss
