Neuroscience pt. 1

Na+ outside, K+ inside

inside is more negative than outside

3 sodium ions for 2 potassium ions

momentary reversal of membrane potential in response to a stimulus

Na+ flowing in, Na+ gates opened, inside becomes positive

K+ flowing out, K+ gates opened, inside becomes negative

after action potential, neuron is unresponsive to signal

wave of action potentials from dendrites down the axon to terminal branches; all or none firing

minimum stimulation for action potential to begin

in myelinated axons, action potentials jump between nodes of Ranvier, resulting in faster signaling

chemical messages released from pre-synaptic neurons into synapse when action potential reaches terminal branches

contain receptors for neurotransmitters; receptors and neurotransmitters bind based on specific shapes

make action potential more likely to happen

make action potential less likely to happen

1. diffusion out of synapse

2. enzymatic degradation

3. reuptake

enzymes destroy neurotransmitters

pre-synaptic cells reabsorb neurotransmitters

enhances normal cellular response by mimicking neurotransmitters because of similar shape -> binds to receptors

prevents normal cellular response by binding to blocking receptor -> shape is not similar enough to bring about response

brain and spinal cord

sensory and motor

afferent nerves, receptors to spinal cord

efferent nerves, spinal cord to effector cells

automatic

fight or flight

rest and digest

fast response, many are processed only in the spinal cord

functions: muscle contraction, learning, memory malfunctions: alzheimer's disease drugs: curare

functions: mood, hunger, sleep, arousal malfunctions: depression drugs: SSRI, ecstasy

functions: movement, attention, emotion, reward center malfunctions: schizophrenia, parkinson's disease drugs: cocaine

functions: released in response to pain, stress and exercise

functions: arousal, attention

malfunctions: insomnia, seizures/tremors drugs: inhibited by caffeine, stimulated by alcohol *inhibitory neurotransmitter

high-speed electric signals along neurons

substances made by one cell that travel in blood to affect target cell

master gland, secretes trophic hormones

controls pituitary gland by secreting trophic hormones

medulla (inner): fight or flight, secretes epinephrine and norepinephrine cortex (outer): long-term stress, secretes cortisols

voluntary