BIPN 100: Week 1

high to low membrane permeability

small hydrophobic molecules (O2, CO2, N2), small uncharged polar molecules (H2O), large uncharged polar molecules (glucose), ions

channel

transport protein that forms a continuous pore from one side of the membrane to the other, transport is only passive

carrier

transport protein that undergoes a conformational change when bound, transport can be passive or active depending on the carrier protein

leak channel

permanently open channel

gated channel

channel that is closed in the cell’s resting state, but opens in response to a stimulus

ligand-gated channel

channel that opens when bound by a specific chemical

mechanically-gated channel

channel that opens in response to membrane distortion

voltage-gated channel

channel that opens in response to electrical voltage

uniporter

carrier protein that transports one molecule/ion, down its concentration gradient

cotransporter

carrier protein that transports more than one molecule/ion, one species goes down its concentration gradient which powers the other to go against its gradient

pump / ATPase

carrier protein that uses energy from ATP hydrolysis to transport one or more molecules/ions, each species goes against its concentration gradient

relative concentrations of ions in human body

higher extracellular concentrations of Na+, Ca2+, and Cl- ; higher intracellular concentrations of K+ and negative anion A-

chemical driving force

diffuses down its concentration gradient

electrical driving force

like charges repel, opposite charges attract

membrane potential

measure of the charge difference between the inside and outside of the cell

equilibrium potential

the membrane potential at which the chemical and electrical driving forces are equal and opposite

Nerst equation

calculates the equilibrium potential of a specific ion

GHK equation

calculates the membrane potential for a cell that is permeable to multiple ions at a time

central nervous system (CNS)

primary processing center of the body consisting of the brain and the spinal cord

peripheral nervous system (PNS)

consists of all the nerves outside of the brain and spinal cord, connects CNS to body

afferent (sensory) division

division of PNS that brings information from the body to the brain

efferent (motor) division

division of PNS that sends information from the brain to the body

somatic sensory

nerves that carry information from the body surface (skin, muscles, joints) to the brain

visceral sensory

nerves that carry information from the internal organs to the brain

somatic motor

nerves that mediate voluntary movements

autonomic (visceral motor)

regulates functions of the internal organs

neuron

basic functional unit of the nervous system

dendrites

receive information from other neurons

cell body

core part of the neuron that contains the nucleus and the cell’s metabolic machinery

initial segment

point at which all received stimuli are integrated; initiates action potential

axon

propogates the action potential to the axon terminals

axon terminals

send chemical messengers to other neurons

neurotransmitters

chemical messengers that bind to another neuron

synapse

junction between two neurons