Chapter 12 – Nervous System Comprehensive Study Notes (copy)

What is the primary function of the nervous system?

To serve as a communication and control super-system linking body and mind.

What types of signals do sensory (afferent) neurons carry?

Sensory signals travel toward the spinal cord and brain.

What does the Central Nervous System (CNS) consist of?

The brain and spinal cord.

What are the two divisions of the nervous system?

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

What is the main role of motor (efferent) neurons?

To send output to effectors such as muscle or gland cells.

What type of glial cell forms the Blood-Brain Barrier (BBB)?

Astrocytes.

What is the function of microglia?

They act as immune cells, removing debris and pathogens in the CNS.

What are the main types of neurotransmitters?

Acetylcholine, biogenic amines, amino acids, and neuropeptides.

What is the difference between EPSP and IPSP?

EPSP (excitatory postsynaptic potential) causes depolarization, while IPSP (inhibitory postsynaptic potential) causes hyperpolarization.

What is Wallerian degeneration?

The process that happens in a severed axon where the distal segment degenerates.

What is saltatory conduction?

The conduction of action potentials along myelinated axons where the action potentials jump between nodes of Ranvier.

What is the function of the Na⁺/K⁺ pump?

It moves 3 Na⁺ out of the cell and 2 K⁺ into the cell, maintaining the resting membrane potential.

What does the term 'axon hillock' refer to?

The region where the axon begins and where action potentials are initiated.

What is the typical resting membrane potential (RMP) for neurons?

Approximately -70 mV.

What is a key characteristic of neurons in terms of longevity?

They often survive for over 100 years.

What are the classifications of neurons based on structure?

Multipolar, bipolar, unipolar (pseudounipolar), and anaxonic.

What characterizes the action potential phase known as depolarization?

Voltage-gated Na⁺ channels open, causing Na⁺ to rush in, moving the membrane potential to +30 mV.

How are neurotransmitters released?

Through exocytosis in response to the influx of Ca²⁺ at the presynaptic terminal.

What is the purpose of the neurilemma in the PNS?

To protect and support axons, and aid in their regeneration after injury.