Term
| Where does digestion take place? |
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Definition
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Term
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Definition
| Muscular contractions which allows food to flow through tract |
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Term
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Definition
| Regulate access to different compartments |
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Term
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Definition
Cleaves macromolecules into their component monomers which the animal then uses to make its own molecules or fuel for ATP production
(Polysaccharides split into simple sugars, Fats digested into glycerol and fatty acids, proteins broken down into amino acids, nucleic acids are cleaved into nucleotides) |
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Term
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Definition
Addition of water breaks bonds - digestion
A variety of hydrolytic enzymes catalyze the digestion of each of the classes of macromolecules found in food |
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Term
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Definition
| After digestion, the animal's cells take up small molecules such as amino acids and simple sugars from the digestive compartment - usually involves active transport |
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Term
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Definition
| Excreted by salivary glands in mouth. Polysaccharide digesting enzyme. |
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Term
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Definition
Moves food to stomach by peristaltic waves
Lubrication |
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Term
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Definition
| Protein-digesting enzymes found in the stomach |
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Term
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Definition
| Neutralizes HCl entering small intestine from stomach |
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Term
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Definition
Bile salts - solubilize water-insoluble fats
Bicarbonate - neutralize HCl entering small intestine from stomach
Organic waste products - elimination in feces |
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Term
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Definition
| Store and concentrate bile between meals |
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Term
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Definition
Enzymes - food digestion
Salt and water - maintain fluidity of luminal contents
Mucus - lubrication |
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Term
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Definition
Starch digestion begins in the mouth by salivary amylase and is completed in the small intestine by pancreatic amylase.
Amylase hydrolyzes carbohydrates down to disaccharide maltose and short chains of glucose molecules. |
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Term
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Definition
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Term
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Definition
All of the ingested secreted protein molecules are broken down to constituent amino acids in the lumen of the gastrointestinal tract and these amino acids are absorbed by the small intestine.
Proteins are broken down to peptide fragments in the stomach by the proteolytic enzyme pepsin and in the small intestine the pancreatic proteases trypsin and chymotrypsin |
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Term
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Definition
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Term
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Definition
Secreted by the pancreas
breaks down peptide fragments |
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Term
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Definition
| Membrane bound protease located in the epithelial cells of the intestinal wall |
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Term
| Digestion and absorption of fats |
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Definition
1. Emulsification of large fat globules by bile salts in duodenum.
2. Digestion of fats by pancreatic enzyme lipase yields free fatty acids and monoglycerides which form micellas
3. Fatty acids and monoglycerides enter epithelial cells by diffusion where they are recombined into fats. Mixed with cholesterol and coated with protein forming chylomicrons.
4. Chylomicrons then transported out via exocytosis and into lacteals. |
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Term
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Definition
| Contains bile salts that emulsifies large fat globules |
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Term
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Definition
| Pancreatic enzyme that yields free fatty acids and monoglycerides which form micellas |
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Term
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Definition
| Combination of fatty acids and monoglycerides that are then mixed with cholesterol and coated with protein |
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Term
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Definition
| Found in stomach. Secrete pepsinogen (inactive form of pepsin which is responsible for the initial hydrolysis of proteins) |
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Term
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Definition
| Found in stomach. Secrete HCl |
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Term
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Definition
| Secrete mucous which lubricates and protects the cells of the gastric wall. |
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Term
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Definition
| Where all the capillaries and veins that drain nutrients from the villi converge. Leads directly to the liver. |
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Term
| Protease Activation in the Duodenum |
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Definition
[image]
Pancreas secretes inactive proteases into the duodenum. Enteropeptidase is a membrane bound enzyme which converts trypsinogen (inactive) into trypsin (active protease) |
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Term
| Hormonal Control of Digestion |
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Definition
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Term
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Definition
Amino acids or fatty acids in the duodenum trigger the release of CCK which stimulates the release of digestive enzymes from the pancreas and bile from the gallbladder.
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Term
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Definition
| secreted by the duodenum inhibits peristalsis and acid secretion by the stomach --> slows digestion acid chyme rich in fats enters the duodenum. |
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Term
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Definition
| From the stomach recirculates via the bloodstream back to the stomach where it stimulates the production of gastric juice |
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Term
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Definition
| Secreted by the duodenum and stimulates the pancreas to release Na bicarbonate which neutralizes acid chyme. |
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Term
| Embyonic development involves: |
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Definition
Cell division
Cell differentiation
Morphogenesis |
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Term
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Definition
| Different kinds of cells are organized into tissues and organs |
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Term
| Difference in gene expression |
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Definition
| Results in a difference between cells in a multi-cellular organism; these differences arise during development as regulatory mechanisms turn specific genes off and on. |
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Term
| Transcriptional regulation |
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Definition
| Results in different cell types which make different proteins |
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Term
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Definition
| Signals from other cells result in activation of a master regulatory gene. Cell (myoblast) is now determined (irreversibly committed to becoming a skeletal muscle cell |
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Term
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Definition
| MyoD protein further enhances production of MyoD by the myoD gene and activates genes for muscle-specific proteins. |
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Term
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Definition
| In the egg; mRNA and proteins (encoded by mother's genome) other substances, and organelles incorporated into egg but have uneven distribution. |
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Term
| Induction by nearby cells |
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Definition
| The cells near the bottom of this embryo are releasing signals that cause nearby cells to alter gene expression (differentiate) |
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Term
| Bicoid protein encodes positional information |
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Definition
1. Bicoid mRNA is deposited by maternal cells at the anterior end of the gg
2. Translation produces Bicoid protein, a transcription factor
3. A gradient of bicoid protein results
4. High concentration of Bicoid stimulate head-specifying genes
Involved in anterior-posterior axis specification |
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Term
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Definition
Regulatory genes that contain a highly conserved nucleotide sequence known as a homeobox. The homeobox is a 180 nucleotide sequence that encodes a 60 amino acid long protein called the homeodomain.
Produce HOX protein (transcription factors) because they bind to specific nucleotide sequences and either activate or repress genes.
-Exhibit a head-to-tail axis that corresponds to the relative location of their genes within the Hox gene cluster |
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Term
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Definition
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Term
| Major processes during vertebrate development |
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Definition
Fertilization
Cleavage
Gastrulation
Neuralation
Organogenesis |
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Term
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Definition
| Hydrolytic enzymes dissolve jelly coat and growing actin filaments from acrosomal process which protrudes and penetrates jelly coat binding to receptors in the egg cell membrane that extend through the vitelline layer |
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Term
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Definition
| Fused membrane becomes depolarized |
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Term
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Definition
| Slow Block to polyspermy; fusion of gamete membranes triggers release of Ca2+ from ER into cytosol --> cortical granules fuse with cell membrane and discharge proteolytic enzymes which degrade proteins binding vitelline layer to plasma membrane --> swelling of perivitelline, hardening of vitelline layer and clipping of sperm-binding receptors |
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Term
| Describe the processes that happen during sea urchin fertilization. |
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Definition
1. Contact - triggers exocytosis from the sperm acrosome
2. Acrosomal reaction
3. Contact and fusion of cell membranes - fused membranes become depolarized (fast block to polyspermy)
4. Entry of sperm nucleus
5. Cortical reaction - slow block to polyspermy |
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Term
| Outline the first few steps of fertilization in mammals |
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Definition
1. Sperm migrates through the coat of follicle cells and bidns to receptor molecules in zona pellucida.
2. Binding induces acrosomal reaction - hydrolytic enzymes into zona pellucida.
3. Breakdown of zone pellucida allows sperm to reach plasma membrane. Membrane proteins bind to receptor on the egg and membranes fuse - triggers cortical reaction.
4. Sperm enters the egg. Egg lacks a centrosome. A centrosome forms around the centriole that was the bsal body of the sperm's flagellum.
5. Enzymes released during the cortical reaction harden the zona pellucida - block to polyspermy |
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Term
| What determines the type of cleavage? |
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Definition
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Term
| What kind of cleavage do sea urchins have? |
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Definition
| complete - very little yolk |
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Term
| What kind of cleavage do frogs have? |
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Definition
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Term
| What kind of cleavage do chicks have? |
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Definition
| Incomplete cleavage - forms blastodisk |
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Term
| What kind of cleavage does drosophila have? |
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Definition
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Term
| Describe what happens in sea urchin gastrulation. |
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Definition
The vegetal pole of the blastula flattens.
Some cells change shape and move inward to form the archenteron.
Other cells break free - becoming primary mesenchyme.
More cells break free - secondary mesenchyme.
The archenteron elongates.
The mouth will form where the archenteron meets ectoderm.
The blastopore will form the anus of the mature animal. |
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Term
| What is meant by temperature dependence of oxygen exchange in water? |
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Definition
| Metabolic rate (and thus the rate of oxygen consumption) rises with an increase in water temperature, especially in ectotherms. The amount of oxygen in solution decreases as the temperature rises |
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Term
| What are some adaptations in respiratory systems that maximize the gas exchange |
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Definition
-Increased surface area
-Maximized partial pressure gradients
-Minimized diffusion path length |
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Term
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Definition
| Active movement of respiratory medium (air or water) over the gas exchange surfaces |
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Term
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Definition
| Active circulation of blood over the gas exchange surfcaes |
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Term
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Definition
| Found in the abdomen of insects which allow gas excahgne and close to limit water loss. Open into trachae that branche into tracheoles, which end in air capillaries. |
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Term
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Definition
| Used by fish through their gills to maximize gas exchange. Gills are supported by gill arches that between the mouth and the opercular flaps. Water flows unidirectionally into the mouth, over the gills, and out from under the opercular flaps. |
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Term
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Definition
| Cvoer the gill filaments. Sites of gas exchange and minimize the diffusion path length (L) between blood and water. |
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Term
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Definition
| Use unidirectional air flow to maintain a high PO2 gradeint. After exhalation bird lungs have very little dead space - also helps to maintain a high PO2 gradient. Birds have air sacs that receive inhaled air but are not sites of gas exchange. |
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Term
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Definition
Air sacs keep air moving through the lungs in a continuous and unidirectional flow:
Air flows unidirectionally through the parabronchi
Inhalation expands the air sacs and exhalation compresses them—fresh air is forced out and passes over the lungs |
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Term
| What two secretions do the mammalian lungs produce that affect ventilation? |
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Definition
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Term
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Definition
| Lines the airways and captures dirt and microorgannisms. |
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Term
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Definition
| Reduce the surface tension of a liquid and make breathing easier. |
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Term
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Definition
| An oxygen transporter. A protein with four polypeptide subunits. One molecule of hemoglobin can bind up to four molecules of oxygen. |
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Term
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Definition
| Each polypeptide in hemoglobin surrounds a heme group. The heme group can bind a molecule of O2. |
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Term
| What happens to CO2 at the tissues? |
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Definition
| Diffuses into interstitial fluid and plasma. 90% diffuses into red blood cell. Some picked up by hemoglobin but most forms carbonic acid. Dissociation produces H+ ions. Hemoglobin picks up the H+ and prevents pH and Bohr shift. |
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Term
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Definition
The dissociation of oxygen and hemoglobin depends on pH.
Drop in pH shifts the curve to the right. Lower pH, more dissociation. Active tissue produces CO2. CO2 and water produced bicarbonate which causes an increase in pH. |
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Term
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Definition
| Both sides of the heart contract at the same time - first the two atria contract, then the two ventricles. |
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Term
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Definition
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Term
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Definition
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Term
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Definition
Can initiate action potentials without input from the nervous system
Ion channels in pacemaker cells are different from other cardiac cells |
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Term
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Definition
Primary pacemaker cells
The resting membrane potential of these cells is not stable so that cells gradually reach the threshold to fire
Action potentials are generated here |
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Term
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Definition
| From sympathetic nerves causes the resting potential to rise more quickly which makes the action potentials closer together |
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Term
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Definition
From parasympathetic nerves has the opposite effect of norepinephrine.
Causes the resting potential to decrease which makes action potentials furhter apart. |
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Term
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Definition
The atrioventricular node consists of non-contracting cells that send action potentials to the ventricles via the bundle of His.
The bundle divides into right and left bundle branches that run to the tips of the ventricles. |
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Term
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Definition
| Spread throughout the ventricles. A contraction spreads rapidly and evenly throughout the ventricles. The delay between the contraction of atria and ventricles ensures proper blood flow. |
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Term
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Definition
The epithelial layer that lines blood vessels
Facilitate the exchange of materials |
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Term
| Arteries (not veins) have: |
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Definition
Thicker walls to accomodate the high pressure of blood pumped from the heart.
Called resistance vessels because their resistance can vary.
Have elastin and collage that allow them to stretch and recoil. |
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Term
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Definition
Thinner-walled and have valves
Called capacitance vessels because of their high capacity to stretch and store blood
Blood flows back to the heart mainly as a result of muscle action. |
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Term
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Definition
A single layer of endothelial cells.
Have tiny holes called fenestrations.
Permeable to water, ions, and small molecules (but not to large molecules).
Highly selective for sizes of molecules that can pass.
B |
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Term
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Definition
| Refers to the high selectivity of brain capillaries, which do not have fenestrations. |
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Term
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Definition
Velocity is inversely related cross-sectional area
V1A1 = V2A2 |
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Term
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Definition
| Pressure inversely related to velocity |
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Term
| Compare blood pressure and osmotic pressure (and when fluids enter/leave) |
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Definition
Blood pressure is higher at the arterial end of the capillary bed and drops at the venous end.
Osmotic pressure is constant along the capillary.
If blood pressure is higher than the osmotic pressure, fluid leaves the capillary
If blood pressure is lower, fluid returns to the capillary |
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Term
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Definition
Accumulation of fluid in extracellular space due to:
Fall in blood protein levels from disease
Histamine release which increases capillary permeability, relaxes smooth muscle in arterioles and raises blood pressure in the capillaries |
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Term
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Definition
| Returns interstitial fluid to the blood |
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Term
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Definition
| Fluid that enters vessels from the lymphatic system |
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Term
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Definition
| Empty into veins in the neck, and results from lymphatic capillaries ultimately merging into two of these |
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Term
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Definition
| Site of lymphocyte production - remove microorganisms and foreign materials by phagocytosis and act as filters |
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Term
| Autoregulatory mechanisms |
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Definition
Local actions in the capillary bed that cause arterioles to constrict or dilate
The nervous and endocrine systems respond to change sin the capillary beds by changes in:
Breathing rate, heart rate, blood distribution |
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Term
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Definition
| A smooth muscle that shuts off blood flow from an arteriole to a capillary bed |
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Term
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Definition
| Stretch receptors; monitor blood pressure changes |
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Term
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Definition
| Send information about blood composition |
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Term
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Definition
| Antidiuretic hormone (vasopressin) is released in response to low baroreceptor activity which results in the kidney re-absorbing more water and increasing blood pressure. |
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Term
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Definition
| Produced when blood supply to the kidney falls which results in reduced flow to peripheral tissues and directs it to essential organs. |
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Term
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Definition
Generated in the bone marrow
Immature red blood cells divide and produce hemoglobin while in the bone marrow.
When mature, organelles break down and cells enter the circulation. |
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Term
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Definition
| A hormone released in the kidney in response to hpoxia, which controls red blood cell population |
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Term
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Definition
| Produced by bone marrow and break off cell fragments called platelets. |
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Term
| What happens when platelets initiate clotting? |
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Definition
-Inactive enzyme prothrombin converts to active form, thrombin.
-Thrombin cleaves fibrinogen and forms fibrin.
-Fibrin threads form mesh that clots blood and seals vessel. |
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Term
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Definition
| Agents that cause disease |
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Term
| What are the three phases of the defense response |
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Definition
Recognition phase (organism must discriminate between self and nonself)
Activation phase - recognition event leads to mobilization of cells and molecules to fight invader
Effector phase - mobilized cells and molecules destroy invader |
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Term
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Definition
| (Innate) act rapidly and include barriers such as skin, phagocytic cells and molecules toxic to invaders. Found in all organisms. |
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Term
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Definition
| (Adaptive/acquired) Aimed at specific pathogens (antibodies) Slow to develop and long-lasting, found in vertebrates. |
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Term
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Definition
Lysozome in gut
Phagocytic cells
Antimicrobial peptides
Recognition proteins |
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Term
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Definition
A receptor on surface of immune cells
Activated by bound recognition proteins |
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Term
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Definition
Binds to pathogen or fragment of pathogen
Bound recognition protein activate "Toll" a receptor on surface of immune cells |
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Term
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Definition
Circulate in body of insect
Inactivate or kill pathogens by disrupting membranes |
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Term
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Definition
Production of mucus
Lysozyme in salvia, mucus, tears
Acidic environment in stomach
pH skin 3-5 from secretion from sweat glands and oil glands |
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Term
| Toll-like-receptors (TLRs) |
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Definition
Most mammalian species have between 10-15 TLRs
signaling - the binding of specific molecules from pathogens to the Toll-like receptor triggers immune defenses
-First trigger phagocytosis |
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Term
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Definition
| A phagocytic cell in the immune system which is the most abundant. |
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Term
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Definition
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Term
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Definition
| Low ability for phagocytosis but help attack parasitic worms |
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Term
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Definition
| Include thymus, bone marrow, spleen, and lymph nodes - essential parts of the defense system |
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Term
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Definition
Contains ions, small molecular solutes, soluble proteins
Red and WBCs and platelets are suspended in plasma |
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Term
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Definition
Fluid derived from blood and other tissues
From tissues, lymph moves into lymph system vessels.
Lymph vessels join and eventually form the thoracic duct, which joins the circulatory vein near the heart |
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Term
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Definition
small, round structures at many sites along the lymph vessels
Contain lymphocytes, a type of WBC.
As lymph passes through the nodes, lymphocytse initiate an immune response if foreign cells or molecules are detected |
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Term
| Two major families of white blood cells (leuokocytes) |
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Definition
Granular cells have granules - vesicles containing defensive enzymes.
Agranular cells, phagocytes and smaller lymphocytes |
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Term
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Definition
proteins that bind specifically to substances identified by the immune system
Antibodies are produced by B cells |
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Term
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Definition
Proteins rae found in two classes:
MHC 1 proteins are found on most cell surfaces
MHC 2 are found on most immune system cells |
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Term
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Definition
| Integral membrane proteins on T cells, recognize and bind nonself molecules on other cells |
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Term
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Definition
| Soluble signaling proteins that bind to a cell's surface receptors and alter that cell's behavior |
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Term
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Definition
The bacteria and fungi that usually live on body surfaces
They are part of the defense system because they compete with pathogens for nutrients and space |
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Term
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Definition
| Found in tears, nasal mucus, and saliva. An enzyme that attacks bacterial cell walls. |
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Term
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Definition
| Produced in mucous membranes; peptides with hydrophobic domains that are toxic to many pathogens. Insert themselves into the plasma membrane of the pathogen and make it permeable. |
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Term
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Definition
| Can be activated by specific or nonspecific mechanisms. Act in a cascade - each protein activates the next. Has antimicrobial proteins. |
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Term
| Complement protein defense |
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Definition
1. Attach to microbes and mark them for phagocytes to engulf
2. Activate inflammation response and attract phagocytes to site of infection
3. Lyse invading cells |
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Term
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Definition
Signaling molecules produced by cells infected by a pathogen
Increase resistance of neighboring cells to the pathogen by:
-Binding to receptors on noninfected cell membranes - stimulate a signaling pathway that inhibits viral reproduction
-Stimulating cells to hydrolyze pathogen's proteins to peptides |
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Term
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Definition
Travel freely in the lymph and circulatory systems and may move out of vessels and into tissues
-Foreign cells, viruses, and fragments become attached t the phagocyte membrane and are engulfed.
-Other agents inside the phagocyte kill the pathogens. |
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Term
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Definition
A type of lymphocyte that can detect virus-infected cells and some tumor cells
-Can initiate apoptosis in these cells
-Can interact with the specific defense mechanisms and lyse cells labeled by antibodies |
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Term
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Definition
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Term
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Definition
| Cells adhering to skin and organ linings;release chemical signals |
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Term
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Definition
| Cytokine that kills target cells and activates immune cells |
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Term
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Definition
| Dilate blood vessels and interact with nerve endings, responsible for pain |
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Term
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Definition
| Amino acid derivative that leads to itching and allergic reactions |
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Term
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Definition
| A possibly lethal condition that results from when the response to a bacterial infection does not remain local and spreads throughout the bloodstream |
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Term
| Four key traits of the specific immune system |
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Definition
Specificity
Ability to distinguish self from nonself
Diversity - response to a wide variety of nonself molecules
Memory |
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Term
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Definition
Lymphocytes are crucial: T cell receptors and antibodies bind to specific non-self molecules (antigens)
Specific sites on the antigens are called antigenic determinants or epitopes. |
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Term
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Definition
Specific portion of a large molecule
A single antigenic molecule can have multiple, different antigenic determinants
The host responds to an antigen's presence with highly specific defenses using T-cell receptors and antibodies. |
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Term
| Distinguishing self from nonself |
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Definition
| The immune system must be able to recognize all the body’s own antigens and not attack them. |
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Term
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Definition
The immune system must respond to a wide variety of pathogens by activating specific lymphocytes.
Each pathogen may exist in many different varieties or strains.
Humans can respond specifically to about 10 million different antigens. |
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Term
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Definition
After one response to a pathogen, the immune system “remembers” the pathogen and can respond more quickly and powerfully if that pathogen invades again.
Vaccination introduces an antigen and the immune system remembers it. |
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Term
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Definition
| Migrate and mature in the thymus |
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Term
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Definition
| Develop in bone marrow (called B because they were discovered in the bursa of Fabricius in birds) |
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Term
| T and B cells have antigen specific receptors |
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Definition
Thousands of receptors on a single cells
The same type of receptor on a single cell |
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Term
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Definition
Idea that through this invertebrates appear to have some degree of immune memory.
Ontogenetic immune priming
Cross-generational immune priming |
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Term
|
Definition
Relies on B cells making antibodies
Antibodies are secreted by B cells and react with antignes in blood, lymph, and tissue fluids
A B cell has the same specific receptors as the antibody on its surface.
The first time an antigen invades, it may bind to the B cell, which then makes multiple copies of the antibody |
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Term
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Definition
Relies on cytotoxic T cells. Detects and destroys virus-infected cells and mutated cells. Carried out by T cells in blood lymph, and extracellular spaces in tissues.
T cell receptors bind to specific antigens, which initiates an immune response that results in destruction of the foreign cell. |
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Term
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Definition
| Expose the structure of the antigen to the T and B cells. |
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Term
|
Definition
| Integrates the two responses and binds to the antigen on a presenting cell |
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Term
| How is diversity generated |
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Definition
| Primarily by DNA changes just after B and T cells are formed. Each B cell is able to produce only one kind of antibody and each T cell has specific T cell receptors. |
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Term
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Definition
| Binding and activation select a particular lymphocyte - it proliferates and generates a clone of genetically identical cells |
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Term
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Definition
| Carry out the attack. Effector B cells (plasma cells) secrete antibodies. Effector T cells secrete cytokines. |
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Term
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Definition
| Long-lived cells that can divide on short notice to produce effector cells |
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Term
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Definition
| When antigen is first encountered, "naive" lymphocytes proliferate to produce clones of effector and memory cells |
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Term
| Secondary immune response |
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Definition
| When antigen is encountered again, memory cells proliferate and launch an army of plasma cells and effector and T cells. |
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Term
|
Definition
| Inoculation with whole pathogens that have been modified so they will not cause the disease |
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Term
|
Definition
| Any immature B and T cells that show the potential to mount an immune response to self antigens undergo apoptosis |
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Term
| What are the two types of effector T cells |
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Definition
T-Helper cells
Cytotoxic T cells |
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Term
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Definition
| Determines the class of antibody - the function and destination |
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Term
|
Definition
| Are specific for each immunoglobulin - responsible for antibody specificity |
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Term
|
Definition
| When DNA is rearranged, errors can occur during recombination, creating new codons. This results in a high spontaneous mutation rate. |
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Term
|
Definition
| Occur when the immune system overreact or is hypersensitive to an antigen and other symptoms |
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Term
|
Definition
clones of B and T cells are produced that are directed against self antigens. Possible hypotheses:
-Failure of clonal deletion
-Molecular mimicry - self has antigens that resemble and are recognized by T cells |
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Term
| Stretch-gated ion channels |
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Definition
| Open in response when the membrane is deformed |
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Term
| Ligand gated ion channels |
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Definition
| Open or close when a specific chemical binds to the channels. Synapses. |
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Term
| Voltage-gated ion channels |
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Definition
| Open or close in response to a change in membrane potential; found in axons and cell bodies and dendrites of some neurons |
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Term
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Definition
| Electrical signal conducted by neurons |
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Term
| How do neurons encode information |
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Definition
| Neurons encode information in action potential frequency |
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Term
| What are the two types of Na voltage gated ion channels |
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Definition
Activation
Inactivation gate
(Both gates must be open for Na to diffuse through the channel) |
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Term
| What kind of gate is the K+ voltage-gated ion channel |
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Definition
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Term
| At resting potential what are the states of the Na and K gates |
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Definition
Na+ activation is closed
Na+ inactivation is open
K+ activation is closed |
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Term
| At initial depolarization what are the states of the Na and K gates |
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Definition
Rapidly opens Na+ activation gate
Slowly closes Na+ inactivation gate
Slowly opens K+ activation gate |
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Term
| What happens in the rising phase? |
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Definition
| When stimulus depolarizes the membrane inactivation gates on some Na+ channels open = Na+ diffuses in - causes further depolarization - more activation gates open (Positive feedback) |
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Term
| What happens in the falling phase |
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Definition
1. Inactivation gates on most Na+ channels (stops Na+ influx)
2. Activation gates on most K+ channels open - rapid |
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Term
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Definition
The membrane permeability to K+ is higher than at rest and membrane potential is closer to Ek than at rest.
The K+ activation gates eventually close and membrane potential returns to the resting potential
The Na+ channel inactivation gates remain closed during the falling phase and the early part of the undershoot |
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Term
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Definition
Depolarize the postsynaptic neuron.
The binding of neurotransmitter to postsynaptic receptors opens gated channels that allow Na+ to diffuse into the cell. |
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Term
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Definition
Hyperpolarize the postsynaptic neuron.
The binding of neurotransmitter to postsynaptic receptors open gated channels that allow K+ to diffuse out of the cell and/or Cl− to diffuse into the cell. |
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Definition
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Definition
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