chapter 11

Anatomy & Basic Divisions. Physiology & Electrical Signals Synaptic Transmission. Disorders & Protection

What are the two principal parts of the nervous system?

The Central Nervous System (CNS), consisting of the brain and spinal cord, and the Peripheral Nervous System (PNS), which includes the nerves outside the CNS.

What are the three main parts of a neuron?

The cell body (contains nucleus and organelles), dendrites (receive incoming information), and the axon (conducts electrical impulses away from the cell body).

Name the four lobes of the cerebral cortex and their primary functions.

* Occipital: Visual information.

Temporal: Auditory information and language comprehension.

Parietal: Interprets sensory information from the skin.

Frontal: Initiates motor activity, responsible for speech and conscious thought.

What is the typical resting potential of a neuron?

–70 mV, where the interior of the cell is negative relative to the exterior.

Define the "All-or-None" principle of action potentials.

If a stimulus reaches the threshold, an action potential is triggered; once triggered, it is always the same in speed and voltage regardless of the stimulus strength.

What is Saltatory Conduction?

A "leaping" pattern of impulse conduction where the signal jumps from node to node along a myelinated axon, speeding up transmission.

What is a Synapse?

A special junction between an axon terminus and a target cell (such as another neuron, muscle cell, or gland).

How do excitatory and inhibitory neurotransmitters differ?

Excitatory neurotransmitters depolarize the postsynaptic cell to approach or exceed the threshold, while inhibitory neurotransmitters hyperpolarize it.

Which neurotransmitter is key for the "Fight-or-Flight" response?

Norepinephrine

What are the three layers of the meninges?

Dura mater, arachnoid, and pia mater.

What characterizes Multiple Sclerosis (MS)?

Progressive damage to the myelin sheaths in the brain and spinal cord, leading to weakness and visual impairment.

What is the primary cause of Parkinson's disease?

The loss of dopamine-releasing neurons.