Functions of the Nervous System

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Questions and Answers

What is the function of the myelin sheath?

To protect the axon, electrically insulate fibers from one another, and increase the speed of nerve impulse transmission (correct)

To synthesize neurotransmitters

To produce nerve impulses

To facilitate the transmission of nerve impulses

Which of the following neurons has an axon that splits into two branches?

Unipolar neuron

Multipolar neuron

Bipolar neuron

Pseudounipolar neuron (correct)

What is the difference between white and gray matter in the CNS?

White matter has a higher concentration of ion channels, while gray matter has a higher concentration of myelin sheaths

White matter has a higher concentration of myelinated axons, while gray matter has a higher concentration of cell bodies and dendrites (correct)

White matter has a higher concentration of dendrites, while gray matter has a higher concentration of axons

White matter has a higher concentration of cell bodies, while gray matter has a higher concentration of myelinated axons

Which cells form the myelin sheath in the CNS?

Oligodendrocytes Signup and view all the answers

What is the purpose of nodes of Ranvier in the myelinated neuron?

To have a high concentration of ion channels to produce nerve impulses Signup and view all the answers

Which type of neuron has two processes and is found in the retina and cochlea?

Bipolar neuron Signup and view all the answers

What is the primary function of supporting cells (Glial cells or Neuroglia) in the nervous system?

To provide support and nutrition to neurons Signup and view all the answers

Which part of a neuron contains the nucleus?

Cell body (soma) Signup and view all the answers

What is the function of dendrites in a neuron?

To receive and transmit impulses towards the cell body Signup and view all the answers

What is the term for the region of the axon near the cell body where nerve impulses originate?

Axon hillock Signup and view all the answers

Which type of neuron conducts impulses out of the CNS to effector organs?

Motor neurons Signup and view all the answers

What is the function of autonomic motor neurons?

To regulate heart rate and blood pressure Signup and view all the answers

What is the primary function of association neurons?

To integrate and process information within the CNS Signup and view all the answers

What is a characteristic of glial cells?

They are capable of mitosis Signup and view all the answers

What is the primary function of sensory neurons in the nervous system?

Receiving and processing sensory information Signup and view all the answers

What is the main function of the central nervous system (CNS)?

Receiving and processing sensory input Signup and view all the answers

What is the main difference between the sympathetic and parasympathetic nervous systems?

One is related to emergency situations and the other is related to normal states Signup and view all the answers

What is the function of the myelin sheath?

Insulating the neuron and facilitating nerve conduction Signup and view all the answers

What are the two principal cell types of the nervous system?

Neurons and glial cells Signup and view all the answers

What is the main function of motor neurons?

Sending motor impulses to effector organs Signup and view all the answers

What is the peripheral nervous system (PNS) divided into?

Somatic and autonomic nervous systems Signup and view all the answers

What is the primary characteristic of neurons that makes them unique?

They are excitable cells Signup and view all the answers

Study Notes

Functions of the Nervous System

The nervous system has three main functions: sensory input, integration of data, and motor output
Sensory input involves sensory neurons receiving information from sensory receptors and sending nerve impulses to the central nervous system (CNS)
Integration of data involves the CNS receiving, processing, and interpreting sensory input, and making decisions
Motor output involves motor neurons sending impulses to effector organs (muscles or glands) in response to sensory input

Classification of the Nervous System

The nervous system is divided into the central nervous system (CNS) and peripheral nervous system (PNS)
The CNS includes the brain and spinal cord
The PNS is further divided into the somatic nervous system (connecting to skeletal muscle) and autonomic nervous system (connecting to smooth muscle, cardiac muscle, and glands)
The autonomic nervous system is further divided into sympathetic nervous system (associated with emergency situations) and parasympathetic nervous system (associated with normal state)

Cell Types of the Nervous System

The two principal cell types are neurons and supporting cells (glial cells or neuroglia)
Neurons are the basic structure and functional units of the nervous system, conducting electrochemical impulses
Glial cells provide support to neurons, surrounding them, holding them in place, providing nutrition, maintaining homeostasis, and protecting them
Glial cells do not conduct nerve impulses and are capable of mitosis

Structure of a Typical Neuron

Neurons have three principal regions: cell body (soma), dendrites, and axon
The cell body contains the nucleus and typical cytoplasmic organelles
Dendrites are cytoplasmic extensions transmitting impulses to the cell body
The axon carries impulses away from the cell body, with the axon hillock being the region where nerve impulses originate
Synaptic knobs (axon terminals) contain neurotransmitters

Classification of Neurons

Functional classification:
- Sensory neurons (afferent neurons) conduct impulses from sensory receptors into the CNS
- Motor neurons (efferent neurons) conduct impulses out of CNS to effector organs
- Association neurons (interneurons) are located entirely within the CNS and serve associative or integrative functions
Structural classification:
- Pseudounipolar neurons have an axon that splits into two branches
- Bipolar neurons have two processes and are found in the retina and cochlea
- Multipolar neurons have one axon and many dendrites and are motor and interneurons
Classification according to myelination:
- Myelinated neurons have a myelin sheath surrounding the axon
- Unmyelinated neurons do not have a myelin sheath

Myelin Sheath

It is a fatty white substance that surrounds the axon, leaving only the nodes of Ranvier exposed
In the PNS, myelin sheath is formed by Schwann cells, and in CNS by oligodendrocytes
The myelin sheath gives the tissue a white color or matter (in the CNS, areas with high concentrations of myelinated axons)
It functions to protect the axon, electrically insulate fibers, and increase the speed of nerve impulse transmission

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Description

Understand the three main functions of the nervous system: sensory input, integration of data, and motor output. Learn how sensory neurons receive information and send nerve impulses to the CNS.