General Functions and Organization of the Nervous System

These flashcards cover key concepts related to the general functions, organization, and cellular aspects of the nervous system.

What are the three general functions of the nervous system?

1. Collects information, 2. Processes & evaluates information, 3. Initiates response to information.

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

The components are the brain and spinal cord.

What is the function of the Peripheral Nervous System (PNS)?

The PNS transmits information to and from the CNS.

What distinguishes the Motor Division from the Sensory Division?

The Motor Division delivers commands from the CNS to effectors, while the Sensory Division sends information from receptors to the CNS.

What type of motor division controls involuntary responses?

Visceral (autonomic) Motor.

What are neurons?

Neurons are the basic units of the nervous system, excitable cells that transmit electrical signals.

What is the function of glial cells?

Glial cells are non-excitable cells that primarily support and protect neurons.

What are the four main classes of neurotransmitters based on their chemical structure?

1. Acetylcholine, 2. Biogenic amines (monoamines), 3. Amino acids, 4. Neuropeptides.

What is myelination?

Myelination is the process by which parts of an axon become wrapped in myelin sheaths composed of glial cell plasma membrane.

What is the absolute refractory period?

The absolute refractory period is the time after the start of an action potential when it is impossible to fire another action potential.

What happens during depolarization in an action potential?

During depolarization, the membrane potential becomes less negative due to the opening of voltage-gated sodium channels.

What is spatial summation?

Spatial summation occurs when multiple locations on a cell's receptive regions receive neurotransmitter simultaneously and generate postsynaptic potentials.

What distinguishes a converging circuit from a diverging circuit in neuronal pools?

A converging circuit has many inputs that converge at a single postsynaptic neuron ('many to one'), while a diverging circuit spreads information from one presynaptic neuron to several postsynaptic neurons ('one to many').

What role do astrocytes play in the CNS?

Astrocytes help form the blood-brain barrier, regulate interstitial fluid composition, support neurons, and regulate synapse formation.

What are the types of ion channels mentioned in the context of neuronal activity?

1. Chemically gated channels, 2. Voltage-gated channels, 3. Modality gated channels.

What is the role of neurotransmitter removal from the synaptic cleft?

Neurotransmitter removal from the synaptic cleft occurs through enzymes, transporters, or diffusion to terminate the signal.

What is the main distinguishing feature of the neuron at rest?

At rest, gated channels are closed, and there is an electrical charge difference across the membrane.