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66 Cards in this Set
- Front
- Back
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What are muscle cells used for?
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-generation of mechanical force and movement
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What are nerve cells used for?
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-rapid communication
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What are connecting/supporting cells used for?
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-structural integrity
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What are epithelial cells used for?
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-protection, selecticve secretion and absorption
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How is tissue integrity maintained?
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-by interconnection b/t ind. cells
-through gap juntions or tight junctions |
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What are gap junctions?
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-pores within cell membrane that allow chemical movement between cells
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What are tight junctions?
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-area in cell membrane that seals off specific chemical movement b/t cells
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Why are different fluid compartments kept separate within the body?
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-b/c of physical barriers and at the expense of enegy
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What is a phospholipid bilayer made of?
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-hydrophilic head and a hydrophobic tail
-contains cholesterol anjd imbedded proteins (integral and peripheral) - |
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What are the integral proteins in a cell membrane?
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-(transmembrane) receptors,pores, ion channels, etc.
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What are peripheral proteins in a cell membrane?
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-enzymatic activities
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What is the nucleus used for?
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-to hold DNA, heredity
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What is within the cytoplasm?
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-cytosol and filaments
-membrane-bound organelles -lysosomes -mitochondria -endoplasmic reticulum (smooth and rough) -golgi apparatus |
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What is RNA interferance? How does is work? Clinical significance?
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-silencing of mRNA
-RNA gets cleaved by an enzyme into siRNAs -siRNA sep.s into single strands -strands bind to mRNA to block translation -can block production of single proteins related to specific diseases |
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How is energy used in cells?
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-by catabolic processes such as oxidative phopsorylation and glycolysis
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What is ATP?
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-molcule that transfers energy for cell work
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What is necrosis?
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-a type of cell death related to cell injury
-necrotic cells swell, organelles deteriorate -leads to cell rupture -cell contents release digestive enzymes that damage nearby cells that result in an inflammation response |
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What is apoptosis?
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-programmed cell death isuially related to tissue remodeling
-intestinal epithelium is relaced every 2-5 days -cell shrinks and pulls away from nearby cells and generally does not induce an inflammation response |
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What is homeostasis?
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-phsyiological system striving to maintain a constant internal environment
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What does homeostasis involve?
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-involves the maintenance of reasonable stable values for specific physiologic parameters over time
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What is the set point of homeostasis?
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is the value of a specific parameter that is physiologically controlled
-if the system is perturbed and the parameter changes, control mechanisms work to bring the value of the parameter back to a set point |
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What is negative feedback?
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-homeostatic control systems that utilize negative feedback to maintain constant conditions
-act to negate change |
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What is positive feedback?
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-initiating stimulus that produces more of the same
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What is the pathway for reflexes wihin a homestatic control system?
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-stimulus-> receptor (skin cells)-> integrating center (brain)-> effector (whatever does changes)
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What is feedback gain?
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-degree of effectivness of a system in maintaining constant conditions
GAIN= value with- value without (feedback)/ value with-control (set pt) value |
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What is diffusion?
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-movement of molecules from one location to another as a consequence of their random thermal motion
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What is passive diffusion?
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-diffusion with no additional energy input
-movement from high to low concentration |
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What is diffusion equilibrium?
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-movement is same in all directions, no further net movement
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How is the rate of diffusion affected?
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-increasing temp.
-decreasing molecular weight -increasing concentration difference -increasing pressure difference -increasing electrical potential difference |
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What does diffusion time depend on?
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-depends on diffusion rate and diffusion distance
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What is simple diffusion?
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-direct lipid solubility, movement through pores or open protein channels
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What is faciliated diffusion?
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-association with an integral protein, or carrier protein, that mediates or faciliates transfer across the lipid membrane
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How is permeability affected within a cell during diffusion?
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-thicker membrane= lower perm
-more soluible lipid= higher perm. -more channels= higher perm. -higher MW= lower perm -greater resistance= lower perm |
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How do you calculate the permeability of a cell's membrane?
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[(# of channels / unit area) x temp.)]/ (resistance x square root of MW)
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How does the rate of diffusion increase within a cell?
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- increase in concentration gradient
-increase in electrical potential difference -increase in pressure (partial pressure=concentration) |
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What is the electrochemical gradient?
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-concentration gradient+ electrical gradient
-may oppose each other or enhance each other |
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What is active transport?
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-transport of chemicals in and out of cell with the required use of ATP to create energy for the mechanism to occur
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What does ATPases or pumps do?
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-primary transport process that directly hydrolyse ATP in the reaction that moves a substance across the membrane
-ex. Na+/K+ ATPase/pump |
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What do co-transporters or symports do?
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-secondary transport process that moves 2 substances in the same direction
- energy is stored in concentration gradient that was established by a primary transport process -ex. Na+-glucose transporter |
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What do counter-transporters/antiports do?
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-secondary active process that moves 2 substances at the same time in opposite directions
-ex. Na+/H+ antiport transporter |
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What is primary active transport?
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-ATP breakdown directly to drive movement
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What type of transport is the sodium-potassium pump?
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-antiport
-primary |
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What type of transport is Ca2- ATPase?
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-uniport
-primary |
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What type of transport is the proton pump?
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-uniport
-primary |
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What type of pump is the H+-K+ ATPase?
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-antiport
-primary |
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What are the functions of the NA+-K+ pump?
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-osmotic stability
-gradient for co-transport -bioelectricity |
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How do you calculate the energy required against a concetration gradient?
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-Energy= 1400log C1/C2
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What is the secondary active transport?
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-energy derived from energy stored in ionic concentration differences created by primary active transport
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What si the order of rates for inter-membrane tranports of molecules?
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-diffusion> faciliated diffusion< primary active transport< secondary active transport
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What uses diffusion in the cell's membrane?
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-dissolution
-leak (pores) -gated channels |
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What uses faciliated diffusion in the cell's membrane?
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-carrier proteins
-uniports |
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What uses primary transports in cell membrane?
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-ATP-ases
-"pumps" |
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What uses secondary active transports in the cell's membrane?
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-symports
-antiports |
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What is phagocytosis?
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-cell engulfs bacterium or other particle into phagosome
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What is endocytosis?
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-membrane surface indents and forms vesicles
-active process which can be nonselective (pinocytosis) or high selective -receptor-mediated uses clarthrin-coated pits |
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What is exocytosis?
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-fusion of vescile with cell membrane to release contents to extracellular side
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What are leak channels?
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-pores that allow specific ions to move across membrane
-not gated -diffusion occurs |
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What is a ligand gated channel?
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-binding of specific chem. (ligand) to membrane protein
-changes conformation transiently -uses faciliated transport ex. nicotinic receptors |
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What are voltage gated channels?
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-change in charge changes confromation transiently to openj
-conducts muscle contraction |
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What are examples of stretch or pressure gated channels?
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-mechanical
-ex. sensory receptors |
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What are examples of phopsylation-gated channels?
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-ex. protein kinase A
-ex. calcium channels |
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What is a Na+ channel?
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-.3 X.5 in diameter
-neg. charged -allows Na to move down gradient (extra to intra) -opposed by outward pump of K -"voltage activated" (fast Na+ channel) -has dual gates |
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What is a fast gate?
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-closed when mem. is polarized, opens when depolarized
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What is a slow gate?
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-closed when mem is polarized, opens when depolarized
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What are K+ channels?
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-pores that leak K+ to move down gradient (intra to extra
-oppossed by action of Na+-K+ pump -K+ ion more permeable, less hydrated, passes pores more easily -single gate (rleative slow opening and closing) -closed when polarized |
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What are calcium ion channels?
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-"voltage gated" (slow Ca++-Na+ channel)
-found on plasma membrane of smooth and cardiac muscle -permeable to Na+ ions -slower act. than fast Na+ channel -Ca++ and Na+ move down gradient into cell |
