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74 Cards in this Set
- Front
- Back
- 3rd side (hint)
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How long is the Digestive Tract?
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17-20 feet from mouth to anus
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More then 10!
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Amylase (which breaks down Starch) is _______ digestion.
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Chemical
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Chewing is an example of what kind of digestion?
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Mechanical
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What is a lysosyme?
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An antibacterial enzyme that "lyses" bacteria.
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The parasympathetic system stimulates...?
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Salivation!
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*drools*
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The sympathetic system inhibits what...?
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Salivation!
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You'll have a cotton mouth
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The strong muscular sack is called what?
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the Stomach!
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Mixing food and gastric secretions makes...?
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Chyme.
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What protects the cells from it's own acid?
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Cells lining the stomach.
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The gastric pits contain how many different types of cells?
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4 different types
1. Mucus Cells 2. Chief Cells 3. Parietal Cells 4. G Cells. |
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What do mucus cells do?
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Mucus cells produce a watery mucus.
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What do chief cells do?
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Chief cells produce pepsinogen which is converted into pepsin.
- This breaks proteins into small peptides. |
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What do parietal cells do?
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Parietal cells secrete HCl (hydrochloric acid) @ a pH of about 1.
- Strong acid is a good solvent, it disinfects and denatures proteins. |
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What do G cells do?
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G cells of the pituitary gland secrete gastrin into the blood stream.
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What does the stomach absorb?
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H2O, ETOH & Glucose: ESPECIALLY nonpolars.
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How often is the lining of the stomach replaced?
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Every 3 days!
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What is an Intrinsic Factor?
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Polypeps produced by the stomach that are necessary for absorption of Vit. B12 in the small intestine.
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Where does most digestion occur?
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In the small intestine aka Duodenum
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How long is the duodenum?
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10 feet long - the absorptive area is about the size of a tennis court!
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Describe the small intestine.
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Highly folded and covered with finger-like villi.
- each one is vascularized & have microvilli - caps in the villi absorb nutrients! |
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What do lacteals absorb?
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Fat.
- absorbed first and carried by lymph vessels. |
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How long does it take for chyme to move through the Duodenum?
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"Several hours."
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How is the pancreas connected to the Small intestine?
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Via the pancreatic duct.
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What does the pancreas secrete?
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A COMPLETE SET OF DIGESTIVE ENZYMES!
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Amylases break down what?
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Carbs.
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Lipases break down what?
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Fats.
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Proteases break down what?
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Proteins.
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What does the Pancreas produce to neutralize stomach acid?
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Bicarbonate.
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What secretes enzymes that performs the final break down of food into small absorbable molecules?
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The Small Intestine's microvilli.
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In the liver, fat must be emulsified by what?
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Bile.
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What in the bile digests fats?
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It has detergent like properties.
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The liver is constantly producing bile, where is it stored?
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Gall bladder.
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After meals what happens with the gall bladder?
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It contracts and sends bile to the Small Intestine.
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Emulsification increases what?
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Surface area.
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About how long is the large intestine (colon)?
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4 feet long.
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What does the colon do?
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It absorbs H20, Vit, Drugs, Suppositories.
- about .5-2 L of H2O a day. |
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The colon secretes..?
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K (potassium)
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Slow movement in the colon allows ________ digest unabsorbed materials.
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Bacteria!
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How much is of bacterial origin?
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1/3.
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Bacteria produces what?
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Flatus; also B & K vitamins
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The colon cannot absorb vitamin B therefore some animals eat their own feces this is called...?
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ccprophagla
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What controls and sequences digestion?
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Both neural and hormonal control!
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The Digest System has it's own...?
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enteric nervous system
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What does the Enteric Nervous System Control?
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Glands, Muscles and motility.
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The length of digestion depends on what?
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The nature of the food.
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Which of the 3 digests quickest?
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Carbs- 1 hour
Proteins- 2-4 hours Fats- 6 hours |
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What are the 4 main hormones involved in digestion?
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1. Gastrin- Is secreted in response to small peptides in the stomach.
- stimulates gastric pits to secrete more - gastrin is clinically important because excessive amounts have been associated with ulcers. - Small intestine contains cells that secrete 2. CCK= cholecystokinin - When chyme from stomach enters intestine. - causes the gall bladder to contract sending stored bile to Small Intestine; & the pancreas to release digestion enzymes. 3. Secretin- 1st hormone discovered. - presence of acid in small intestine stimulates the release of secretin. - secretin causes pancreas to release bicarbonate which neutralizes the acid in the chyme. 4.GIP- Gastric Inhibitory Peptide - inhibs stomach muscles and muscles. - release is elicited by high fat or acid in chyme. - slows rate of stomach emptying so the small intestine can emulsify the fat and neutralize acidic chyme a little at a time. |
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Do hormones play a role in the colon's motility?
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No
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How is the colon controlled?
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It is controlled entirely via enteric nervous system and autonomic nervous system.
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What is Evolution?
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Genetic change in a population of organisms.
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What is natural selection?
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Difference in survival and reproduction of individuals because of different genotypes.
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What is adaptation?
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Adaptation is the outcome of natural selection
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Natural selection acts on individuals but what actually evolves?
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The population
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What is the unit of evolution?
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The population.
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What is a population?
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A localized group of individuals who belong to the same species.
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What is a species?
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A group of populations with potential to interbreed and produce viable offspring in nature.
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All the genes in the entire population is known as the...?
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Gene pool.
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What is a phenotype?
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The physical manifestation of expressed genes
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What is a genotype?
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All the genes contained in its diploid cells.
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What is an allele?
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Alternative state of a gene.
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Incomplete dominance is when..?
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Offspring is different from both parents.
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Gene Interaction is when..?
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2 or more genes determine a single phenotypes trait.
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Pleiotrophy is defined as...
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instances in which genese have more than one effect on phenotype.
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Epigenetic Inheritance refers to...
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reversible, heritable, changes in gene expression that occur w/ out a genetic change.
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Epigenetic Inheritance blocks gene expression using 2 major mechanisms. What are they?
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Acetylation & Methylation
1. Acetylation: of chromosomal histones. 2. Methylation of cytosines on DNA a. Can be affected by environmental factors that affect DNA methyltransferases. b. A variety of compounds are considered to be epigenetic carcinogens. - increase cancers BUT are not mutagens. - includes DES, hexachlorobenzene, Ni + |
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Gene imprinting occurs when...
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allele that is expresed is determined only by which parent contributes it.
- Imprint is usually erased and then reestablished by each generation in germ cells. - Males imprint one way, females another. |
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The Parental Conflict Hypothesis states:
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Father is more interested in growth of offspring at the expense of mom.
a. Mom has to juggle own survival and offsprings. b. paternally imprinted genese tend to be growth promoting, maternals tend to be growth limiting. |
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What is the Hardy Weinburg Equilibrium?
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It describes a non-evolving population. The gene pool doesn't change!
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H.W. Principle:
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Sexual reproduction by itself DOES NOT change the gene pool.
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H.W. Equilibrium:
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Allows you to test whether a gene pool is static or evolving.
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What is a locus?
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Location of gene on chromosome.
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p2 (squared) + 2pq + q2 (squared) = 1
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H.W. Equation for population with only 2 alleles.
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Gene flow is...
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the movement of genes from one population to another.
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Gene flow makes populations more genetically similar.
Example? |
Races in the U.S. via. interbreeding.
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