physio chapter 6
Terms
undefined, object
copy deck
- 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
- homeostasis
- 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
- 20
- what are variants of one protein called
- subtypes or isoforms
- what are variants of one enzyme called
- isozymes
- 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?
- both.
- can cytokines travel through the circulation?
- yes.
- 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