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49 Cards in this Set

  • Front
  • Back
how often does the our blood make a complete circuit thru the body
q minute
how fast do nervous electrical signals travel
up to 120 m/sec = 268 mi/hr
what are the 3 routes cells communicate with each other
simple diffusion, circulatory system, nervous system
process of maintaining a stable internal environment
what body systems control homeostasis
endocrine and nervous
how many cells in human body
75 trillion
what are the 2 types of physiological signals
electrical and chemical
what are the cells that receive signals called
target cells or targets
what are the 4 basic methods of intercellular communication
gap junction, contact dependent signals, local communication, long distance comm
what is a gap junction
direct cytoplasmic transfer of electrical and chemical signals between adjacent cells
what's contact dependent signal
surface molecules on adjacent cells bind
what's local communication
via chemicals in ecf
what's long distance comm
combo of electrical and chemical signals
what are the gap channels made out of
membrane spanning chons = CONNEXINS, that form a channel (CONNEXON) that can open/close
when channel is open, connected cells function as
a single cell with multiple nuclei (synchtium)
how many different variants of connexins are there
what are variants of one protein called
subtypes or isoforms
what are variants of one enzyme called
where are gap junctions found
every cell type
what do contact dependent signals require?
cell to cell contact
where does contact dependent comm occur
in immune system, and during growth and development
what are CAM's
cell adhension molecules. membrane spanning chons (like G proteins)
what is a paracrine and an example
para = besides. crine = secrete. chemical secreted by ANY cell to act on cells BESIDE it. example - histamine (released by damaged cells)
what's an autocrine
auto- self. acts on cell that secreted it.
how to paracines and autocrines reach their targets
diffusion thru interstitial fluid, very limited in distance, act on same or very close cells
groups of molecules that act as paracrines (2)
cytokines (peptides) & eicosanoids (lipids)
what cells are targets for hormones
ONLY those with receptors for that hormone
which system uses both chemical and electrical signals to communicate, and how does this work
nervous. elecrical signal travels neuron to the end - translated into chemical signal secreted by neuron (NEUROCRINE)
neurocrine signals (3)
neurotransmitter if diffuses to target with rapid response. neuromodulator if acts slowly. neurohormone if diffuses into bloodstream
what's a cytokine
paracine regulatory peptide comm molecule, somewhat like hormone. secreted by all eukaryotocytes. act on broad spectrum of targets. made on demand. example erythropoietin
are cytokines autocrines or paracrines?
can cytokines travel through the circulation?
what's a ligand
a signal molecule, the finger that pushes the elevator button. aka first messenger.
what activates the receptor
ligant receptor binding (finger pushing elevator button)
what does the receptor do once activated
activates 1+ intercellular signal molecules
what does the last signal molecules in pathway do
initiates synthesis of TARGET PROTEIN or modifies existing target chon to create RESPONSE
signal pathway steps
signal molecule --> receptor chon --> intercellular signal molecules --> target proteins --> response
what are the 2 types of chemical signal molecules (hint - membrane permeability)
lipophobic and lipophilic
where are target protein cell receptors located?
plasmalemma, cytosol, nucleus
what do the lipophilic signal molecules do & what happens next
diffuse thru p/l bilayer & bind to cytosolic or nuclear receptors. usu this turns on gene & directs nucleus to make new mRNA (transcription)
what is mRNA
messenger RNA. gets protein recipe from DNA in nucleus (transcription). leaves nucleus and teaches recipe to cell (translation).
what do lipophobic signal molecules do?
they can't get in the cell so they bind to external receptor chons
why do we care about receptor proteins
1/2 of pharma drugs act on receptors
what are the 4 categories of receptors
ligand-gated channel, receptor enzyme, g-protein linked receptor, integrin
what's signal transduction
transmission of info across membrane using chons
what's the first law of thermodynamics
energy cannot be created nor destroyed, only changed in form
what's the 2nd law of thermodynamics
entropy - things go from order to disorder and randomness
what are 2 ways animals store energy in their bodies
glycogen in fat cells and in chemical bonds
what's potential vs kinetic energy
kinetic - actual movement, potential - has the potential to be converted into kinetic