Essentials of Human Anatomy & Physiology Ch 7: The Nervous System Organization Quiz

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Questions and Answers

What is the function of the endocrine system in maintaining body homeostasis?

Releasing hormones into the blood (correct)

Interpreting sensory information

Producing electrical nerve impulses

Issuing instructions to body organs

Which organ serves as the integrating and command center of the nervous system?

Heart

Brain (correct)

Spinal cord

Endocrine system

What percentage of the total body weight does the adult human brain approximately weigh?

3% (correct)

What is the approximate diameter of the human spinal cord?

2cm Signup and view all the answers

Which system in the body controls with rapid electrical nerve impulses?

Nervous system Signup and view all the answers

What is the weight of the spinal cord approximately?

~35g Signup and view all the answers

What is the main role of the nervous system?

Controlling and communicating with body cells Signup and view all the answers

Which term describes the ability of an organism or organ to detect external stimuli?

Sensitivity Signup and view all the answers

What type of response does motor output in the nervous system lead to?

Activation of body effectors Signup and view all the answers

How does the nervous system communicate with body cells?

Via electrical impulses Signup and view all the answers

What is the general role of sensory input in the nervous system?

Gathering information about stimuli Signup and view all the answers

Which part of the nervous system decides if action is needed based on sensory input?

Central nervous system Signup and view all the answers

What type of cells form a barrier between capillaries and neurons in the brain?

Astrocytes Signup and view all the answers

Which type of cells dispose of debris, dead brain cells, and bacteria in the brain?

Microglia Signup and view all the answers

Which cells produce fatty insulating coverings called myelin sheath around nerve fibers in the central nervous system?

Oligodendrocytes Signup and view all the answers

What type of cells protect and cushion neuron cell bodies?

Satellite cells Signup and view all the answers

Which cells form myelin sheath around nerve fibers in the peripheral nervous system?

Schwann cells Signup and view all the answers

What is the main function of neurons?

Conducting nerve impulses Signup and view all the answers

Which part of a neuron contains the nucleus and serves as the metabolic center?

Cell body Signup and view all the answers

What is the function of axons in a neuron?

Conduct impulses away from the cell body Signup and view all the answers

Where are most neuron cell bodies located?

In the gray matter Signup and view all the answers

What structures produce myelin sheaths in neurons?

Schwann cells Signup and view all the answers

Which part of a neuron conducts impulses toward the cell body?

Dendrites Signup and view all the answers

What is the main function of conductivity in neurons?

Transmitting impulses to other neurons, muscles, or glands Signup and view all the answers

During depolarization of a neuron's membrane, what ion flows inside the membrane?

Sodium (Na+) Signup and view all the answers

What occurs during repolarization of a neuron's membrane?

Potassium ions rush out of the neuron Signup and view all the answers

How does the action potential move along the entire axon of a neuron?

By propagating an impulse involving sodium and potassium ions Signup and view all the answers

What part of a neuron plays a key role in communicating with another neuron at a synapse?

Axon terminal Signup and view all the answers

What is the significance of myelin sheath in nerve impulse propagation?

It enhances and speeds up impulse transmission Signup and view all the answers

Study Notes

Supporting Cells in the Nervous System

Astrocytes: abundant, star-shaped cells that form a barrier between capillaries and neurons, protecting from harmful substances and controlling the chemical environment of the brain.
Microglia: spider-like phagocytes that dispose of debris, dead brain cells, and bacteria.
Ependymal cells: line cavities of the brain and spinal cord, helping circulate cerebrospinal fluid and forming a protective cushion around the CNS.
Oligodendrocytes: produce fatty insulating coverings called myelin sheath around nerve fibers in the CNS.
Satellite cells: protect and cushion neuron cell bodies.
Schwann cells: form myelin sheath around nerve fibers in the PNS.

Organization of the Nervous System

The nervous system does not work alone to regulate and maintain body homeostasis; the endocrine system is a second important regulating system.
The endocrine system produces hormones that are released into the blood, bringing about deliberate effects.

Structural Classification of the Nervous System

The nervous system is divided into two main subdivisions: CNS (brain and spinal cord) and PNS (nerves outside the CNS).
The CNS acts as an integrating and command center, interpreting sensory information and issuing instructions.
The adult human brain weighs about 3 pounds (1,300-1,400 g) and is about 2% of the total body weight.
The spinal cord weighs about 35 gm, is 42-45 cm in length, and has a diameter of about 2cm.

Functions of the Nervous System

The nervous system is the master controlling and communicating system of the body.
It has three main functions: sensory input, integration, and motor output.
Sensory input involves gathering information from inside and outside the body.
Integration involves processing and interpreting sensory input and deciding on a response.
Motor output involves responding to integrated stimuli, activating appropriate body effectors (muscles or glands).

Neurons

Neurons are nerve cells specialized to transmit messages (nerve impulses).
They have three main regions: cell body, dendrites, and axon.
The cell body contains the nucleus and metabolic center of the cell.
Dendrites are armlike fibers that conduct impulses toward the cell body.
Axons are fibers that conduct impulses away from the cell body, ending in axonal terminals.
Axonal terminals contain vesicles with neurotransmitters and are separated from the next neuron by a synaptic cleft.

Nerve Fiber Coverings and Impulses

Schwann cells produce myelin sheaths in a jelly-roll-like fashion, with nodes of Ranvier (gaps) at regular intervals along the axon.
Myelin sheaths increase the speed of impulse transmission.
An action potential is generated when a stimulus depolarizes the neuron's membrane, allowing sodium ions to flow in and potassium ions to flow out.
The sodium-potassium pump restores the original membrane configuration, requiring ATP.

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Description

Test your knowledge on the organization of the nervous system with this quiz based on Chapter 7 of 'Essentials of Human Anatomy & Physiology Seventh Edition' by Elaine N. Marieb. Learn about the functions, classifications, and structures of the central and peripheral nervous systems, nervous tissue, neurons, and neuroglia.