Nervous System Overview: Structure & Function

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Questions and Answers

What are the two structural divisions of the nervous system?

Somatic Nervous System (SNS)

Autonomic Nervous System (ANS)

Central Nervous System (CNS) (correct)

Peripheral Nervous System (PNS) (correct)

What are the subdivisions of the nerves in the Peripheral Nervous System?

Cranial Nerves, Spinal Nerves, Autonomic Neurons

What is the main function of the cranial nerves?

To monitor internal conditions

To serve structures of the head and neck (correct)

To convey impulses away from the CNS

To transmit sensory information to the spinal cord

How do cranial and spinal nerves differ in terms of their function?

Cranial nerves carry signals to and from the brain. Signup and view all the answers

What do sensory signals do?

They are picked up by sensory receptors and carried into the CNS. Signup and view all the answers

What is the function of motor signals?

They cause muscles or glands to contract or secrete. Signup and view all the answers

What components make up the somatic body region?

Structures external to the ventral body cavity, such as appendages. Signup and view all the answers

The somatic nervous system consists of sensory and motor fibers to and from internal organs.

False Signup and view all the answers

Visceral sensory receptors gather information from which part of the body?

Internal viscera Signup and view all the answers

What types of neurons are present in the autonomic nervous system?

Sympathetic and parasympathetic neurons Signup and view all the answers

What are neurons supported by in the CNS and PNS?

Neuroglia Signup and view all the answers

How is information transmitted through neuron cells?

Through axons via synapses. Signup and view all the answers

What distinguishes motor neurons from sensory neurons?

Motor neurons convey efferent impulses, sensory neurons convey afferent impulses. Signup and view all the answers

In the PNS, axons larger than 1-2 micrometers in diameter are insulated by ______.

myelin sheaths Signup and view all the answers

What type of glia cell myelinates axons in the CNS?

Oligodendrocyte Signup and view all the answers

What type of glia cell surrounds neurons in the PNS?

Schwann cell Signup and view all the answers

Study Notes

Structural Classification of the Nervous System

Central Nervous System (CNS): Comprises the brain and spinal cord.
Peripheral Nervous System (PNS): Consists of nerves located outside the CNS.

Subdivisions of Nerves in the PNS

Includes three main types of nerves:
- Cranial Nerves (CN): 12 pairs that connect to the brain and serve the head and neck.
- Spinal Nerves (SN): 31 pairs linked to the spinal cord, serving the body wall and limbs.
- Autonomic Neurons (ANS): A two-neuron system controlling smooth muscle, cardiac muscle, and glands.

Details of Cranial, Spinal, and Autonomic Nerves

Cranial Nerves: Specific functions and targets for head/neck structures; each is unique.
Spinal Nerves: Uniform in function, primarily serving the body wall and limbs.
Autonomic Nervous System: Connects CNS and peripheral targets with preganglionic and postganglionic neurons.

Functional Classification of the Nervous System

Cranial nerves transmit signals between the brain and PNS.
Spinal nerves transmit signals between the spinal cord and PNS.

Sensory Afferent Receptor Signals

Sensory receptors throughout the body gather signals and transport them to the CNS.

Motor Efferent Neuronal Signals

Motor signals are dispatched from the CNS to muscles or glands, leading to contraction or secretion.

Body Region Divisions: Somatic Body Region

Function: Monitors external environment and body position.
Components: Includes skin, skeletal muscles, and bones outside the ventral body cavity.

Somatic Body Region: Sensory and Motor Components

Somatosensory Receptors: Receive signals from skin, skeletal muscle, bones, and joints.
Somatomotor Neurons: Control voluntary movements to the same structures, forming the somatic nervous system.

Body Region Divisions: Visceral Body Region

Function: Oversees internal organ systems and conditions, primarily within body cavities.

Visceral Body Region: Sensory and Motor Components

Visceral Sensory Receptors: Detect signals from internal organs and organ systems.
Visceral Motor Neurons: Direct signals to smooth muscle, cardiac muscle, and glands via the autonomic nervous system.

Cells of the PNS and CNS: Neurons

Both CNS and PNS consist of neurons and supporting tissue called neuroglia.

Information Transmission in Neurons

Neurons receive information through axons, which communicate at synapses with other neurons via dendrites or the soma.

Motor Neurons vs. Sensory Neurons

Motor Neurons: Transmit efferent impulses from CNS to effectors.
Sensory Neurons: Relay afferent impulses from peripheral receptors to CNS.

Myelination of Neuronal Axons

Axons over 1-2 micrometers in diameter are insulated by myelin sheaths.
CNS axons are myelinated by oligodendrocytes, while PNS axons are myelinated by Schwann cells.

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Description

This quiz covers the structural and functional classification of the nervous system, focusing on the central and peripheral divisions. It also explores the various subdivisions of nerves in the peripheral nervous system. Test your knowledge with these flashcards!