Nervous System Lecture Review

Flashcards covering the structure, function, divisions, and histology of the nervous system based on lecture notes.

What are the main components of the Central Nervous System (CNS)?

Brain and Spinal cord

What are the main components of the Peripheral Nervous System (PNS)?

Cranial nerves, Spinal nerves, Ganglia, Peripheral nerves, Sensory receptors, and Enteric plexuses

How do the endocrine system and the nervous system differ in their response signals?

The endocrine system has slow response signals via hormones, while the nervous system has rapid response signals via electrochemical impulses.

What are the three main functions of the nervous system?

Sensory, Integrative, and Motor

Which type of neurons carry impulses from the periphery to the CNS?

Afferent (sensory) neurons

Which part of the nervous system is responsible for analysis and storage of information?

The Central Nervous System (CNS) using interneurons

Which type of neurons carry impulses from the CNS to effectors (muscles/glands)?

Efferent (motor) neurons

What are the primary functions of the Peripheral Nervous System (PNS)?

Communication between the CNS and the rest of the body, receiving sensory input, and carrying motor output from CNS to effectors.

What are the three divisions of the Peripheral Nervous System (PNS)?

Somatic Nervous System, Autonomic Nervous System (ANS), and Enteric Nervous System

Which division of the PNS controls voluntary muscle movement?

Somatic Nervous System

Which two divisions make up the Autonomic Nervous System (ANS), and what is their general effect?

Sympathetic Nervous System (fight or flight) and Parasympathetic Nervous System (weep-or-sleep, rest or digest), having opposite effects.

Where are enteric plexuses found, and what do they control?

They are found in the Gastrointestinal (GI) tract and control GI smooth muscle and secretions.

What are the two major types of cells in nervous system histology?

Neurons and Neuroglia

What is the function of neuroglia?

They do not conduct impulses but support, protect, and nourish neurons.

Which specific neuroglial cell type in the CNS forms the blood-brain barrier?

Astrocytes

Which specific neuroglial cell type produces the myelin sheath in the CNS?

Oligodendrocytes

What is the function of microglia?

They are small, phagocytic cells derived from monocytes.

Which specific neuroglial cell type lines ventricles in the brain and the central canal of the spinal cord, helping produce cerebrospinal fluid?

Ependymal cells

Which specific neuroglial cell type produces the myelin sheath around neurons in the PNS?

Schwann cells

What is the neurolemma?

The outer portion of a Schwann cell, consisting of its cell membrane, nucleus, and cytoplasm.

What is the primary function of a neuron?

To conduct nerve impulses (action potentials) from one area to another, initiated by a stimulus.

What are Nissl bodies, and what is their function?

Rough ER in the cell body of a neuron, used for protein synthesis required for growth.

Which part of a neuron typically carries impulses toward the cell body?

Dendrites

Which part of a neuron typically carries impulses away from the cell body and is often myelinated?

Axon

What is the purpose of the myelin sheath?

It acts as an insulator around the axon, making impulse travel faster.

What are Nodes of Ranvier?

Gaps between myelin sheaths (or between Schwann cells in the PNS).

What are synaptic end bulbs (SEB) and what do they contain?

Enlarged ends of axon terminals that contain synaptic vesicles with neurotransmitters (NT).

What is a synapse or synaptic cleft?

The junction between two neurons where a message travels across from a pre-synaptic neuron to a post-synaptic neuron.

Name two common neurotransmitters and briefly describe their effect.

ACh (excitatory) and GABA (inhibitory). (Other examples: Norepinephrine, dopamine, serotonin, endorphins).

What is a 'nerve'?

A bundle of neurons in the PNS, with connective tissue.

What is a 'tract'?

A bundle of neurons in the CNS, without connective tissue.

What is 'ganglia'?

A group of neuron cell bodies in the PNS.

What is 'nucleus'?

A group of neuron cell bodies in the CNS.

What is 'white matter'?

Myelinated nervous tissue, containing myelin sheath.

What is 'gray matter'?

Unmyelinated nervous tissue, without myelin sheath.

Which type of neuron is the most common, having many dendrites and one axon?

Multipolar neuron

Which type of neuron has one axon and one dendrite?

Bipolar neuron (e.g., in retina, inner ear, olfactory area).

Which type of neuron starts as bipolar but has an axon and dendrite that fuse, appearing as one projection from the cell body?

Unipolar neuron (e.g., sensory/afferent neurons).

Describe a 'diverging circuit' in neuronal networks.

One pre-synaptic neuron stimulates more than one post-synaptic neuron.

Describe a 'converging circuit' in neuronal networks.

Several pre-synaptic neurons stimulate fewer post-synaptic neurons.

Can neurons in the PNS regenerate if cut?

Yes, if the cell body is undamaged and Schwann cells are active, forming a regeneration tube.

Can neurons in the CNS regenerate if cut?

No, because there are no Schwann cells to form a regeneration tube, and astrocytes form scar tissue while inhibiting chemicals are present.