Physiology Chapter 4 Flashcards
( cengage) (30 cards)
Membrane potential is related to the uneven distribution of what two positively charged ions?
sodium and potassium
What are the two basic forms of electrical signals?
graded potentials and action potentials
As the triggering event gets stronger, what type of gated channels open up more frequently or for a longer duration?
Sodium Channels
What is the temporarily depolarized region of a membrane called?
active area
What property do insulators demonstrate that greatly hinders movement of electrical charge?
high resistance
In general terms, what sort of distance do graded potentials die out over?
Short Distances
Depolarization from the resting potential of -70 mV proceeds slowly until it reaches a critical level known as ____.
threshold potential
A voltage-gated sodium channel can exist in how many different conformations?
three
The resting membrane is ____ more permeable to potassium than to sodium.
25-30x
What ensures the one-way propagation of an action potential away from the initial site of activation?
Refractory period
The strength of a stimulus is coded by the ____.
Frequency of action potentials
On what three structures can a neuron terminate?
muscles, gland, or other neuron
What are the two types of synapses between neurons?
electrical and chemical
A typical synaptic delay lasts for approximately ____.
0.5 t0 1 millisecond
The binding of a neurotransmitter to inhibitory synapses increases the permeability of the subsynaptic membrane to ____.
Potassium or chloride
What neurotransmitter is made from typtophan?
Seratonin
What class of drugs selectively blocks the reuptake of serotonin into presynaptic axon terminals?
selective serotonin reuptake inhibitors (SSRIs)
What term refers to the branching of axon terminals so that a single cell synapses with and influences many other cells?
divergence
How many types of extracellular chemical messengers or signal molecules are used for indirect cell communications in the body?
four
What paracrine is released from a specific type fo connective tissue cell during an inflammatory response?
Histamine
what term refers to any enzyme that transfers a phosphate group from ATP to a particular intracellular protein?
protein kinase
Messenger binding to a __ activates tyrosine kinase
receptor-enzyme complex
Eicosanoids are modified from ___.
arachidonic acid
What type of eicosanoids invovle local messengers in inflammatory response and cause profound airway constriction characteristic of asthma?
leukotrienes
