Unit 1.3 Flashcards
Levels of organization in the body
1- Chemical (atoms forming molecules)
2- Cellular (molecules forming organelles, such as mitochondria)
3- Tissue (similar cells and surrounding materials)
4- Different tissues combined to form organs)
5- Organ system level- (ex- stomach and intestines make up an organ system)
6- Organism- organ systems make this up
Components and functions of the cardiovascular system
Components: Heart, blood vessels and blood
Functions: Transport of nutrients, O2, CO2 and hormones. Immune response, body temp, homeostasis
Components and functions of the lymphatic system
Components: Lymph vessels, nodes and organs
Functions: defense, removes foreign matter from the blood and lymph, combats diseases and pathogens. Fluid homeostasis
Fat absorption
Components and functions of the digestive system
Components: mouth, esophagus, stomach, small and large intestines, liver, gall bladder, pancreas, rectum
Functions: Performs mechanical and chemical processes of digestion and assimilation of nutrients and elimination of wastes
The portal vein circulation transports:
Water soluble nutrients from the small intestine to the liver
What nutrients does the portal vein transport?
Sugars, amino acids, water-soluble vitamins and minerals (trace minerals are transported in blood bound to protein)
The lymphatic system passes:
Lipid soluble nutrients and large particles
Lipids
Lipid-soluble vitamins
The lymphatic system empties into:
Veins leading to the heart
Function of the digestive system
Digestion
Absorption
Transport
Storage
Excretion
Functions of the mouth and salivary glands
Chew food
Perceive taste
Moisten food
Lubricate food with mucus
Release starch-digesting enzyme
Initiate swallowing reflex
Functions of the esophagus
Lubricate with mucus
Move food to stomach by peristaltic wages (swallowing)
Functions of the stomach
Store, mix, dissolve and continue digestion of food
Dissolve food particles with secretions
Kill microorganisms with acid
Release protein-digesting (pepsin) enzyme
Lubricate and protect stomach surface with mucus
Regulate emptying of dissolved food into small intestine
Produce intrinsic factor for vitamin B-12 absorption
Functions of the liver
Produce bile to aid for digestion and absorption
Function of the gallbladder
Store, concentrate and later release bile into the small intestine
Function of the pancreas
Secrete sodium bicarbonate and enzymes for digesting carbohydrate, fat, and protein
Function of the small intestine
Mix and propel contents
Lubricate with mucus
Digest and absorb most substances using enzymes made by the pancreas and small intestine
Function of the large intestine
Mix and propel contents
Absorb sodium, potassium, and water
House bacteria
Lubricate with mucus
Synthesize some vitamins and short-chain fatty acids
Form feces
Functions of the rectum
Hold feces and expel via the anus (opening to the outside of the body)
The GI tract, AKA:
The alimentary canal
A long, hollow muscular tube that extends from mouth to anus
GI tract (AKA alimentary canal)
The GI tract consists of:
Mouth
Esophagus
Stomach
Small intestine
Colon
Rectum
Accessory organs of the digestive system
Salivary glands
Liver
Gallbladder
Pancreas
The wall of the GI tract consists of what 4 layers?
Mucosa
Submucosa
Muscle
Serosa
The saliva consists of what?
Solvent
Enzymes
Mucus
Others
Daily volume of saliva
8000-1500 ml (1000 ml on average)
Percentage of saliva that is water
> 95%
What is the digestive enzyme that aids in partial digestion of starch?
Alpha-amylase (ptyalin)
Ptyalin is inactivated by what?
Low pH of the stomach
What is the favorable pH range for amylase activity?
6-7
Saliva Mucus consists of:
Mostly water
Electrolytes (K+, HCO3-)
Glycoproteins (mostly polysaccharides with some protein, mucin)
Lubricant
Purpose of lubricant in the mucus in saliva
Facilitates swallowing
Coats wall of gut and prevents food from sticking to it
Resistant to breakdown by digestive enzymes
Small buffering capacity (protein and HCO3-)
Facilitates adherence of fecal material and removal of feces
What type of enzyme is lysozyme?
Digestive enzyme
Purpose of lysozyme in saliva
Breaks down cell wall of bacteria (has beta1->4 glycosides activity) and allows entry of thiocyanate
Oxidation of thiocyanate by H2O2 (Source: oral bacteria) to bacterial metabolites (hypothiocyanate and hypothiocyanous acid)
Purpose of R-Protein in saliva
Stabilized released vitamin B-12 from food
Essential for vitamin B-12 absorption
Capacity of the stomach
Approx 6 cups
Parietal cells secrete:
Hydrochloric acid
Purpose of hydrochloric acid
AIDS protein digestion
Solubilizes minerals for absorption
What do chief cells secrete?
Enzymes
After ____ hours, food in the stomach is transformed into:
2-4 hours
Chyme
Mucus layer of the stomach prevents:
Auto-digestion
Where will you see secretion of the intrinsic factor? (IF)
What secretes it?
Stomach
Parietal cells
Daily volume of gastric secretions. What does this consist of?
About 1500ml (approx 6 cups)
Mostly water
Hydrochloric acid
Mucus
Pepsinogen
Intrinsic factor
Purpose of hydrochloric acid
Kill some food bacteria*
Initiates activation of pepsinogen *
Denatures and facilitates digestion of dietary protein
Partially denatures dietary protein
Solubilizes and keep minerals reduced to facilitate absorption
Releases food-bound vitamin B-12 and allows binding to R-Protein
Ideal pH for pepsinogen activation, partial digestion of dietary protein and binding of vitamin B-12 and R-Protein
1-2
Mucus in the stomach is secreted by:
Goblet cells
Pepsinogen is activated to active:
Pepsinogen
What is intrinsic factor?
A glycoprotein that binds to vitamin B-12- Releases it from R-protein in the small intestine and to carriers in the ileum allowing vitamin B-12 absorption
A hormone that stimulates (with acetylcholine) acid secretion by parietal cells and decreases appetite and food intake
Histamine
What secretes histamine?
Enterochromaffin-like cells (ECL)
What is a hormone that stimulates pepsinogen and acid secretion
Gastric
What secretes gastrin?
Gastrin (G) cells
What is a hormone that acts as a short-term appetite stimulant? Let’s the brain know it is hungry
Ghrelin
What secretes ghrelin?
Ghrelin cells
Review slide 22
Slide 22
Function of the lower esophageal sphincter
Prevent backflow (reflux) of stomach contents in into the esophagus
Function of pyloric sphincter
Control the flow of stomach contents into the small intestine
Function of the sphincter of oddi
Control the flow of bile from common bile duct into the small intestine
Function of ileocecal sphincter
Prevent the contents of the large intestine from reentering the small intestine
Function of the anal sphincter
Prevent defecation until person desires to do so.
Muscular contraction involving progressive movement of food from one point to another along the GI tract
Peristalsis
95% of digestion takes place where?
Small intestine (mostly in duodenum and upper jejunum)
Properties of small intestine
Folded walls and villi
Absorptive cells
How often is the body’s entire supply of enterocytes replaced?
Every 2-5 days
Small intestine secretions
Water and mucus
Ions (Na+, K+, Ca2+, Cl-, HCO3-)
Enteropeptidase
Sucrose
Lactose
Maltese
Isomaltase
Glucoamylase
Peptide PYY
Gastric Inhibitory peptide
Purpose of enteropeptidatse
Starts activation of pancreatic zymogen
Active trypsin activates:
Completes its own activation
Activates other zymogens
What acts as a short-term appetite suppressor
Peptide PYY
What secretes peptide PYY
Small and large intestines into the blood
Gastric Inhibitory peptide (GIP) is secreted by:
It inhibits:
It stimulates:
Small intestine into the blood
Stomach motility
Insulin secretion
Secretin is secreted by:
It stimulates:
Duodenum and jejunum into the blood
Secretion of pancreatic bicarbonate
Cholecystokinin is secreted by:
It stimulates:
It inhibits:
Duodenum and jejunum into the blood
Pancreatic secretion (mostly zymogens)
Stomach motility
Fats are absorbed as ____ by:
MAGS
Passive transport
Proteins are absorbed as ___ ___ ___ by:
Free amino acids
Secondary active transport using a sodium gradient
Glucose and galactose is absorbed by:
Secondary active transport using a sodium gradient (SGT)
Fructose is absorbed by:
Passive transport (GLUT5)
Liver and gallbladder secrete:
Bile
The pancreas secretes:
Pancreatic juice
Digestive enzymes
Bicarbonate
Hormones
Pro-lipases and proteases released in the small intestine and active by trypsin
Zymogens
Activation of trypsin is initiated by:
Enteropeptidase (an active intestinal protease)
Pancreatic secretion is regulated by _______ and by the intestinal hormones _______ and _______
Acetylcholine
Cholecystokinin and secretin
What is the peptide hormone that decreases blood glucose and regulates metabolism of carbs and lipids?
Insulin
Insulin is mostly release by:
Beta cells because of high blood glucose
What is the peptide hormone that stimulates release of glucose from liver and regulates metabolism of carbs and lipids?
Glucagon
Glucagon is release by:
Alpha cells because of low blood glucose
Bile consists of:
Water (about 95%)
Bile salts (emulsifier)
Cholesterol (emulsifier)
Lecithins (emulsifiers)
Fatty acids (emulsifiers)
Bilirubin (for elimination in feces)
Ions (Na+, K+, Ca2+. Cl-, HCO3-)
What is found in the large intestine?
Indigestible food stuff
Mucus-producing cells
Bacteria (probiotics and probiotics)
Are there villi in the large intestine?
Enzymes?
No
No
What is absorbed in the large intestine?
Water, some minerals and vitamins
What are live microorganisms that provide health benefits when they are consumed in sufficient amounts
Probiotics
What are non-digestive carbohydrates that promote the growth of beneficial bacteria in the large intestine
Probiotics
Where are probiotics found?
In fermented foods, such as yogurt and miso (fermented soybean paste) and sold in capsules and powder
Probiotics may help to prevent:
Diarrhea, food allergies and colon cancer
May also treat irritable bowel syndrome and inflammatory bowel disease
Review slides 47 and 48
47 and 48
Inulin is a ______ made of several units of ______
Inulin
Fructose
Where is inulin found?
Chicory, wheat, onions, garlic, asparagus and bananas
Why are inulin and other related compounds, such as fructans added to some processed foods?
To add texture, bulk and potential health benefits
Factors of the rectum
Stool elimination (facilitated by fiber-rich diets)
Muscle contraction
Anal sphincters
Primary nutrients absorbed in the stomach
Alcohol (20%) and water (minor amount)
Primary nutrients absorbed in the small intestine
Calcium, magnesium, iron, other minerals, glucose, amino acids, fats, vitamins, water (70-90%) Alcohol (80%), bile acids
Primary nutrients absorbed in the large intestine
Sodium, potassium, fat acids, gases, water (10-30%)
What happens with bile in the liver
Bile acids convert into bile salts
Bile salts are transported small intestine via bile in gallbladder
What happens with bile in the small intestine?
Bile salts convert to bile acids by intestinal bacteria
Bile acids transported back to the liver via the portal vein
How is adipose tissue stored
Fat mostly
What does the blood store?
Glucose and amino acids
What is stored in the liver
Glucose (glycogen), vitamins and minerals
What is stored in the muscle
Glycogen and amino acids (protein)
What is stored in the bones
Protein and minerals
Stomach acid reflux into the esophagus
Dysfunction of the esophageal sphincter
Gastroesophageal reflux disease (GERD)
GERD symptoms are ____, ____ and if left untreated can lead to:
Pain
Inflammation
Esophageal cancers
Erosion of lining of stomach, esophagus or small intestine due to gastric acid and enzymes
Peptic ulcers
80% of patients with peptic ulcers end up with what type of infection?
Helicobacter pylori infection
Causes of peptic ulcers
Stress, medication, smoking
Peptic ulcer inflammation can lead to..
Gastric cancers
What are some medications that can lead to digestion and health problems?
Proton pump inhibitors
Antacids
Antibiotics
Phytochemicals
Combination of abdominal cramps, grassiness, bloating and irregular bowel movement can be symptoms of:
Irritable Bowel syndrome
Cause of IBS
Therapy includes:
Cause unknown— poorly digested carbs such as fructose, sugar alcohols likely
Eating high fiber diet, avoiding gassy foods and dairy
Chronic immune mediated disease that targets small intestinal cells due to:
Genetic predisposition
Gluten sensitivity
Malabsorption of nutrients
Celiac disease
Gallstones are mainly _____ and not enough:
Cholesterol (80%)
Bile salts
What is nutritional genomics?
Study of interactions between nutrition and genetics; includes nutrigenetics and nutrigenomics
What is nutrigenetics?
Study of the effects of genes on nutritional health, such as variations in nutrient requirement and responsiveness to dietary modifications
What is nutrigenomics?
Study of how food impacts health through its interaction with out genes and its subsequent effect on gene expression
Impact and significance of nutrigenomics:
Enhance the ability of health professionals to help individuals manage diseases and optimize health
What are some nutritional diseases with a genetic link?
Heart disease
Hypertension
Obesity
Diabetes
Cancer
