Human Nervous System I - Physiology Lab Notes

These flashcards cover key terms and concepts from the physiology lab notes on the human nervous system, designed for effective study and review.

Neuron Anatomy

The structure of a neuron including its nucleus, dendrites, cell body, axon hillock, axon, myelin sheath, and synapse.

Dendrites

Branch-like structures of a neuron that receive input signals.

Axon hillock

The initial segment of the axon where action potentials are initiated.

Myelin sheath

A layer of insulation around the axon that increases the speed of nerve impulse transmission.

Synapse

The junction between the axon terminal of one neuron and the dendrite of another where communication occurs.

Postsynaptic neuron

The neuron that receives signals in a synapse.

Presynaptic axon terminal

The end of the axon from which neurotransmitters are released.

Synaptic cleft

The space between presynaptic and postsynaptic neurons.

Hebbian theory

A theory stating that neurons that fire together wire together, focusing on synaptic plasticity.

Glial cells

Support cells in the nervous system that maintain homeostasis, form myelin, and provide support and protection.

Astrocytes

Glial cells that support neuronal function and maintain the blood-brain barrier.

Ependymal cells

Glial cells that produce cerebrospinal fluid (CSF) and line the ventricles of the brain.

Oligodendrocytes

Glial cells that produce myelin in the central nervous system.

Schwann cells

Glial cells that produce myelin in the peripheral nervous system.

Node of Ranvier

Gaps in the myelin sheath that facilitate rapid conduction of action potentials.

Action potential

A rapid increase and decrease in membrane potential that propagates a signal along an axon.

Resting membrane potential

The electrical potential difference across the plasma membrane of a resting neuron, typically around -70 mV.

Nernst Equation

An equation used to calculate the equilibrium potential for a specific ion based on its concentration gradients.

Goldman Equation

An equation that predicts resting membrane potential considering the contributions of multiple ions.

Graded potentials

Changes in membrane potential that vary in size and decay over distance; they can be excitatory or inhibitory.

Threshold potential

The critical level to which a membrane potential must be depolarized in order to initiate an action potential.

Refractory period

The period during which a neuron is unresponsive to further stimulation following an action potential.

Presynaptic inhibition

Inhibition of neurotransmitter release from a presynaptic neuron.

Postsynaptic inhibition

Inhibition of the response of a postsynaptic neuron to neurotransmitter.

Long-term potentiation (LTP)

A lasting increase in synaptic strength following high-frequency stimulation.

Long-term depression (LTD)

A lasting decrease in synaptic strength following low-frequency stimulation.

Neurotransmitter

Chemical messengers released from presynaptic neurons that transmit signals across synapses.

Ionotropic receptors

Receptor channels that mediate rapid synaptic responses by altering ion flow.

Metabotropic receptors

G protein-coupled receptors that mediate slower, longer-lasting synaptic responses.

Cholinergic receptors

Receptors that respond to the neurotransmitter acetylcholine; include nicotinic and muscarinic types.

Graded potential amplitude

The strength of a graded potential, which can vary depending on the initial stimulus.

Chemical synapse

A synapse that uses neurotransmitters to communicate between neurons.

Electrical synapse

A synapse where electrical signals pass directly through gap junctions, less common than chemical synapses.

Neurocrines

Chemical messengers in the nervous system, including neurotransmitters, that communicate between neurons.

Calmodulin Kinase II (CamKII)

An enzyme that is activated by calcium and is involved in signaling pathways that affect synaptic function.

Second messenger pathways

Intracellular signaling pathways activated by receptor-ligand binding that initiate various cellular responses.

Hyperkalemia

An elevated level of potassium in the blood that can affect cell excitability.

Hypokalemia

A low level of potassium in the blood that can lead to hyperpolarization of neurons.