essay questions

What are the three fundamental characteristics of neurons?

Excitability, conductivity, and secretion.

Define excitability of neurons.

The ability of a neuron to respond to a stimulus and generate an electrical signal.

What is the role of conductivity in neurons?

The ability to propagate an electrical signal (action potential) rapidly along the plasma membrane.

Define secretion in the context of neurons.

The ability to release neurotransmitters at axon terminals in response to an electrical signal.

What are dendrites primarily responsible for?

Receiving chemical signals (neurotransmitters) from other neurons.

What is the function of the axon in a neuron?

Transmitting electrical signals (action potentials) away from the cell body.

What do synaptic vesicles contain?

Neurotransmitter molecules.

What is the role of neurofibrils in neurons?

Providing structural support and aiding in intracellular transport.

What type of cells are most brain tumors likely to originate from?

Glial cells.

What is the resting membrane potential (RMP) of a neuron?

Typically around -70 mV, with the inside being negative relative to the outside.

What ions are at higher concentration outside a neuron at resting membrane potential?

Na⁺ (Sodium) and Cl⁻ (Chloride).

What are EPSPs?

Excitatory Postsynaptic Potentials generated by positive ion influx.

What are IPSPs?

Inhibitory Postsynaptic Potentials generated by negative ion influx or positive ion efflux.

What is the threshold potential for triggering an action potential?

Typically around -55 mV.

What occurs during depolarization of a neuron's membrane?

Rapid influx of Na⁺ ions makes the inside of the membrane positive.

What happens during repolarization of a neuron's membrane?

Efflux of K⁺ ions returns the membrane potential to negative.

How do action potentials propagate in unmyelinated versus myelinated axons?

Unmyelinated axons propagate action potentials continuously, while myelinated axons conduct via saltatory conduction.

What neurotransmitter can generate either EPSP or IPSP?

Acetylcholine (ACh).

What is the deepest meningeal layer?

Pia Mater.

What is the role of the hypothalamus in hunger regulation?

Controls appetite through opposing neuronal effects in the arcuate nucleus.

What is the primary function of the olfactory nerve?

Smell.

Explain decussation in the nervous system.

The crossing over of nerve fibers from one side of the CNS to the other.