Exam 1 (Chapter 6) Flashcards
what are the two types of basic physiological signals? what is the difference between them?
electrical: changes to a cell’s membrane potential
-depolarization & hyperpolarization
chemical: molecules secreted by cells into the ECF
-act as ligands that bind to receptor proteins
-majority of communication (NT, hormones)
what four things are under local communication?
Gap Junctions
Contact-Dependent Signaling (juxtacrine)
Paracrine Signals
Autocrine Signals
what are gap junctions?
allow adjacent cells to exchange components of their cytoplasm
-direct connection
-electrical signal
-connexion proteins (not always open)
what is contact-dependent signaling?
membrane molecules connect through a ligand & a receptor
-not directly connected
-uses CAM’s (cell adhesion molecules)
what are paracrine signals?
chemical signal released from the cell
-diffuses to adjacent cells
what are autocrine signals?
signal that secretes and acts on itself
what two things under long-distance communication?
endocrine glands
neurons
what do neurons secrete for signaling? (general term & descriptions of the three types)
neurocrines (general term)
-NT: synapse present, RAPID
-neuromodulator: SLOW
-neurohormone: chemical released into blood
what type of communication are cytokines? examples of cytokines? what do cytokines do to the body?
-BOTH local & long distance communication
-EX: interferons, interleukins, GFs, TNFs, chemokines
-initially: modulate immune system
-now: cell development & differentiation, immune response
what is the generic template for signal pathways?
1) signal molecule (the ligand)
2) receptor protein (where ligand binds)
3) intracellular signal molecules (activated pathway)
4) target proteins (modified)
5) response (gene regulation)
what are characteristics of lipophilic / hydrophobic signal molecules? (make sure to mention speed)
-lipid loving, water fearing
-can easily diffuse through
-intracellular receptors in cytoplasm or nucleus
-alters gene expression
-SLOW
what are characteristics of lipophobic / hydrophilic signal molecules? (make sure to mention speed)
-lipid fearing, water loving
-binds receptor on the surface / membrane of target cells that are embedded in the plasma membrane
-RAPID
what is the general template for signal transduction? how does it relate to signal pathways?
1) 1st messenger (ligand)
2) transducer (receptor)
3) 2nd messenger (intracellular signal molecule, amplifies signal)
4) target proteins (kinase, phosphatase)
5) response
what is a cascade?
waterfall effect in signal transduction
what is amplification?
one ligand generating many intracellular molecules in signal transduction
-increases the number of 2nd messengers
-EX: adenylyl cyclase, phospholipase C
what are the four classes of surface receptors?
receptor channels
G-protein coupled receptors (GPCRs)
Receptor Enzymes
Integrin Receptors
what are receptor channels?
ligand binds receptor & opens / closes ion channel
-ions move w/ electrochemical gradient
-changes the membrane potential (depolarization & hyperpolarization)
-RAPID
EX: ACh opening Na+ channel causing a depolarization and the muscle contracts
what are GPCRs?
alters activity of enzymes and opens ion channels
-cytoplasmic tail of GPCR is linked to the G-protein
EX: cAMP pathway, phospholipase C pathway
what are the (7) steps of the cAMP pathway?
1) signal molecule binds GPCR (ligand)
2) G-protein activated
3) adenylyl cyclase activated (amplifier)
4) ATP converted to cAMP (2nd messenger)
5) protein kinase A activated (target)
6) target proteins phosphorylated
7) cell response
what are the steps of the phospholipase C pathway?
1) signal molecule binds GPCR (ligand)
2) G-protein activated
3) PLC activated (amplifier)
4) phospholipid molecule is used to make DAG & IP3
5a) DAG activates protein kinase C
5b) IP3 causes release of intracellular stores of Ca2+ in the ER
what are the two parts of receptor enzymes?
-receptor region
-enzymatic region
what is the function of the receptor region on receptor enzymes? which side are they on?
binds to a ligand
-extracellular side
what is the function of the enzymatic region on receptor enzymes? which side are they on? what are some examples?
catalyzes a rxn (phosphorylates!)
-cytoplasmic side
-cytokines fall into this receptor class!
EX: tyrosine kinase (insulin receptor), guanylyl kinases
what is the structure of integrin receptors?
they go across the entire membrane and connect to a cytoskeleton on the inside of the cell through an anchor protein
-interact with extracellular matrix (defines tissue types)
what are the functions of integrin receptors?
binds ligand and then activates intracellular enzymes & alters organization of cytoskeleton
-types of ligands: proteins of extracellular matrix, antibodies, clotting factors
what is special about calcium?
very versatile!
-can be a 2nd messenger, ligand, or have ICF and ECF properties
-enters ICF through gated channels (voltage, ligand, mechanical)
-released from ICF by 2nd messengers that are stored in the ER
what are some functions of calcium in the body?
-smooth muscle contraction -> calmodulin
-binding regulatory proteins -> cytoskeleton
-exocytosis of vesicles
-insulin release
when gases are signaling molecules, are they local or long distance? short or long acting?
local communication
short acting (short 1/2 life)
what are the effects of nitric oxide (NO) as a signaling molecule?
-most common!!
-makes smooth muscles in blood vessel relax (vasodialation)
-acts as NT in the brain (Viagra)
what are the effects of carbon monoxide (CO) as a signaling molecule?
-vasodilation (similar to NO)
-neural tissue
what are the effects of hydrogen sulfide (H2S) as a signaling molecule?
-relaxes blood vessel (vasodilation)
-cardio effects
are lipids a type of paracrine or autocrine signal?
paracrine
what are Eicasanoids? (what are they derived from, what are their two types)
-lipid soluble
-local acting signal
-derived from arachidonic acid
-TYPES: leukotrienes, prostanoids
what is the synthesis pathway of the two eicasanoids?
1) PLA2
2) arachidonic acid
3a) lipogenase makes leukotrines
3b) COX 1&2 makes prostanoids
what is a common function of leukotrines?
asthma & allergy
what is a common function of prostanoids?
inflammation, pain, fever
what type of drug is used to inhibit prostanoids?
NSAID’s (non steroidal anti inflammatory drugs)
-aspirin, ibuprofen
-targets COX enzyme
what is an example of having multiple ligands for 1 receptor?
EPI & NE both can bind adrenergic receptors (alpha 1&2, beta 1&2)
-competition for same receptor
what is an agonist?
structurally similar, binds & mimic primary ligand
what is an antagonist?
binds & blocks primary ligand
-inhibits response
EX: Beta-blockers
what is an example of having one ligand that can have multiple receptors?
-having different responses to the same signal
-dependent on the receptor (not the ligand!)
EX: epinephrine
-alpha1 receptor -> vessel constricts (intestinal vessel)
-beta2 receptor -> vessel dilates (skeletal vessel)
EX: ACh
-binding to both muscarinic & nicotinic receptors
what is saturation?
process that occurs when no more of something can be absorbed, combined with, or added
-limited by the number of receptors present
what is down-regulation?
-decrease in the number of receptors
-decrease response to a signal
what is desensitization?
-chemically modifying the receptor (adding phosphate, methyl..)
-decrease response to a signal
what is up-regulation?
-increase number of receptors
-increase response to a signal
what are some ways you can decrease response to a signal?
-less signal (less secretion, destruction, uptake of signal)
-down-regulation
-desensitization
what are some ways you can increase response to a signal?
-more signal
-up-regulation
what are three ways you can terminate a signal?
-destruction of signal through enzymes
-uptake of signal by surrounding cells
-receptor down-regulation
according to Cannon, what regulates the internal environment in a control system?
nervous system (autonomic NS)
what is tonic control?
always some level of activity (make system work more/less)
EX: vessels are always open
-regulate relaxation or contraction w/ one regulator
what is antagonistic control?
what turns the activity up / down
EX: HR is regulated by sympathetic & parasympathetic NS (can be both)
-opposing effects w/ two separate regulators
what are central receptors?
receptors in the brain or close to the brain
-special senses: vision, sound, smell, taste (NOT TOUCH)
what are peripheral receptors?
everything else that isn’t in the brain or a special sense
what are the two types of reflex pathways? what are two differences?
Simple: 1 integrating center, FASTER
Complex: multiple integrating centers, SLOWER
which reflex pathway, neural or endocrine, has a higher specificity? faster? longer duration?
higher specificity: neural
faster: neural
longer duration: endocrine
which reflex pathway, neural or endocrine, only uses chemical signals?
endocrine
how is the signal intensity of the neural reflex pathway increased?
increasing the frequency of the signal
-each signal is identical in strength, so you must adjust the frequency
how is the signal intensity of endocrine reflex pathway increased?
increasing the amount of hormone secreted
what is the sensor for the neural, neuroendocrine, and endocrine reflex pathways?
N: receptor
NE: receptor
E: itself
what is the input signal for the neural, neuroendocrine, and endocrine reflex pathways?
N: afferent signal
NE: afferent signal
E: none
what is the integrating center for the neural, neuroendocrine, and endocrine reflex pathways?
N: NS
NE: NS
E: endocrine system
what is the output signal for the neural, neuroendocrine, and endocrine reflex pathways?
N: efferent signal
NE: efferent signal
E: hormone
what is the target for the neural, neuroendocrine, and endocrine reflex pathways?
N: muscle, gland, adipose tissue
NE: most cells in body (blood)
E: most cells in body (blood)
what is the response for the neural, neuroendocrine, and endocrine reflex pathways?
N: contraction, secretion, metabolic effects
NE: enzymatic rxns, membrane transport, cell proteins
E: enzymatic rxns, membrane transport, cell proteins
where do afferent signals go to?
integrating centers
where do efferent signals go to?
targets
what is released from the neuroendocrine reflex?
neurohormone from NS cell
-enters bloodstream
what are three general categories of responses in a reflex pathway?
-Cellular Response (smooth muscle of vessel contracts)
-Organ / Tissue Response (blood vessels decrease in diameter)
-Systemic Response (overall increase in BP)
what flashcard number is the best number to end on???
69
;)
