Neurobiology 1: Nervous System Organization & Cell Types

Flashcards covering the organization of the nervous system, principal cell types including neurons and various glial cells, and key terminology differentiating CNS and PNS structures, based on Neurobiology 1 lecture notes.

What are the two principal parts of the nervous system?

The Central Nervous System (CNS) and the Peripheral Nervous System (PNS).

What structures make up the Central Nervous System (CNS)?

The brain and spinal cord.

What is the primary role of the Central Nervous System (CNS)?

It is the integration and control center, interpreting sensory input and dictating motor output.

What does the Peripheral Nervous System (PNS) consist of?

Nerves that extend from the brain and spinal cord, including spinal nerves and cranial nerves.

What are the two principal cell types found in nervous tissue?

Neurons (nerve cells) and Neuroglia (glial cells).

Which nervous system cells are excitable and transmit electrical signals?

Neurons.

Which nervous system cells surround and wrap delicate neurons, and are about 50 times more abundant than nerve cells?

Neuroglia (glial cells).

Which glial cells are the most abundant, versatile, and highly branched, clinging to neurons, synaptic endings, and capillaries in the CNS?

Astrocytes.

What are some key functions of astrocytes?

Support and brace neurons, control the chemical environment (forming the Blood Brain Barrier), guide young neurons, and participate in information processing.

Which small, ovoid glial cells with thorny processes monitor neurons and can transform to phagocytize microorganisms and neuronal debris?

Microglial cells.

Which glial cells line the central cavities of the brain and spinal column, forming a permeable barrier between cerebrospinal fluid (CSF) and tissue fluid, and may be ciliated to circulate CSF?

Ependymal cells.

Which branched glial cells wrap CNS nerve fibers, forming insulating myelin sheaths in thicker nerve fibers?

Oligodendrocytes.

Which PNS glial cells surround neuron cell bodies in the PNS and function similarly to astrocytes?

Satellite cells.

Which PNS glial cells surround all peripheral nerve fibers, form myelin sheaths in thicker peripheral nerve fibers, and are vital to the regeneration of damaged peripheral nerve fibers?

Schwann cells.

What is the structural unit of the nervous system that conducts impulses?

Neurons.

What are the three main characteristics of neurons?

Extreme longevity, mostly amitotic (do not divide), and a high metabolic rate.

Which structural class of neurons is the most abundant in the body and the major type in the CNS?

Multipolar neurons.

Which structural class of neurons is rare and found in special sensory organs like the olfactory mucosa, eye, and ear?

Bipolar neurons.

Which structural class of neurons is found mainly in the PNS, common in dorsal root ganglia of the spinal cord and sensory ganglia of cranial nerves?

Unipolar (pseudounipolar) neurons.

What are clusters of neuron cell bodies called in the CNS?

Nuclei.

What are clusters of neuron cell bodies called in the PNS?

Ganglia.

What are bundles of neuron processes (fibers) called in the CNS?

Tracts.

What are bundles of neuron processes (fibers) called in the PNS?

Nerves.

Which part of a neuron receives incoming signals and typically contains ligand-gated and/or GPCR-gated ion channels?

Dendrites.

Which part of a neuron is responsible for biosynthesis and signal integration?

The cell body (soma).

What is the function of the axon hillock?

It is the action potential generation zone.

Which part of a neuron is responsible for impulse conduction via action potentials, utilizing voltage-gated Na and K channels?

The axon.

Which part of a neuron is responsible for the secretion of neurotransmitters and contains voltage-gated Na, K, and Ca channels?

Nerve termini (axon terminals).