Nervous System Part 2

What are the three main functions of the nervous system?

Sensory input, integration/processing, and motor output.

Name the two main cell types in the nervous system.

Neurons and neuroglia.

What is the basic structure of a neuron?

Cell body, dendrites (receive signals), and axon (transmits signals).

What is the function of the myelin sheath?

To insulate axons and increase the speed of nerve impulse conduction.

What are nodes of Ranvier?

Gaps in the myelin sheath where ion exchange occurs, speeding up impulse transmission.

What are the four types of neuroglia in the CNS?

Astrocytes, oligodendrocytes, microglia, and ependymal cells.

What is the primary function of Schwann cells in the PNS?

They produce the myelin sheath around peripheral nerve fibers.

What is resting membrane potential?

The stable, negative charge of a neuron at rest (about -70 mV).

Define depolarization.

The process where the inside of a neuron becomes less negative, initiating an action potential.

What is an action potential?

A rapid change in membrane potential that allows neurons to transmit signals.

Explain repolarization.

Returning the membrane potential to its resting negative state after an action potential.

What is a synapse?

The junction between two neurons where neurotransmitters facilitate signal transmission.

Name an excitatory neurotransmitter and its role.

Glutamate; it increases the likelihood of an action potential in the postsynaptic neuron.

Name an inhibitory neurotransmitter and its function.

GABA; it decreases the likelihood of an action potential in the postsynaptic neuron.

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

The brain and spinal cord.

What is the Peripheral Nervous System (PNS), and what does it include?

Nerves outside the CNS, including cranial and spinal nerves.

How many segments does the spinal cord have?

31 segments, each with a pair of spinal nerves.

What are the main functions of the spinal cord?

To transmit impulses to and from the brain and to house spinal reflexes.

What are the three layers of the meninges?

Dura mater, arachnoid mater, and pia mater.

Describe the dura mater.

The tough outermost layer, containing blood vessels, forming partitions, and a sheath around the spinal cord.

What are the four main lobes of the cerebrum?

Frontal, parietal, temporal, and occipital.

What is the function of the cerebrum?

It is involved in sensory processing, motor control, and higher mental functions like reasoning and memory.

What are the three parts of the brainstem?

Midbrain, pons, and medulla oblongata.

What is the role of the medulla oblongata?

It regulates vital functions like heart rate, blood pressure, and respiratory rate.

How many pairs of cranial nerves are there?

Twelve pairs.

What is the primary function of the optic nerve (Cranial Nerve II)?

Vision.

What is a reflex arc?

The pathway followed by nerve impulses in a reflex, involving sensory and motor neurons.

Give an example of a simple reflex.

The patellar reflex, also known as the knee-jerk reflex.

What are ventricles in the brain?

Connected cavities filled with cerebrospinal fluid (CSF) that protect and nourish the brain.

Where is cerebrospinal fluid produced?

In the choroid plexuses of the ventricles.

What is the primary role of the limbic system?

It controls emotions and behavior, influencing survival instincts.

Name a key structure in the limbic system associated with emotion.

The amygdala.

What is the function of the thalamus?

It sorts and directs sensory information to appropriate areas of the cerebral cortex.

How does the hypothalamus contribute to homeostasis?

It regulates vital functions like body temperature, hunger, and the endocrine system.

What are the two divisions of the autonomic nervous system?

Sympathetic (activates "fight or flight") and parasympathetic (promotes "rest and digest").

Which neurotransmitter is primarily associated with the sympathetic nervous system?

Norepinephrine.

What are ascending tracts in the spinal cord responsible for?

Carrying sensory information to the brain.

What are descending tracts?

Pathways that carry motor signals from the brain to muscles or glands.

Which hemisphere is typically dominant for language-related activities?

The left hemisphere.

What functions are typically associated with the nondominant hemisphere?

Nonverbal functions, body orientation in space, and emotional expression.

What is the role of the basal nuclei?

To help control voluntary movement and produce dopamine.

Which diseases are associated with altered activity in the basal nuclei?

Parkinson’s disease and Huntington’s disease.

What are the primary functions of the cerebellum?

Coordinating muscle activity, maintaining posture, and ensuring smooth movements.

Name the main spinal nerve plexuses.

Cervical, brachial, and lumbosacral plexuses.

Which plexus includes the phrenic nerve, and what is its function?

Cervical plexus; it controls the diaphragm for breathing.