Chapter 2 – Anatomy and Physiology Nervous System
Tip Sheet
Nervous System – Responsible for coordinating the many activities performed inside and outside the body. Every square
inch of the human body is supplied with fine fibers known as nerves; there are more than 100 billion nerve cells, known
as neurons, in the body.
a. Neurology – The scientific study of the structure, function, and pathology of the nervous system. The nervous
system is one of the most important systems of the body; controls and coordinates the functions of all other
systems, making them work harmoniously and efficiently.
b. Nervous System Divisions
● Central System - Principal parts are the brain, spinal cord, spinal nerves, and cranial nerves. It controls
consciousness and all mental activities, voluntary functions of the five senses (seeing, hearing, feeling,
smelling, and tasting), and voluntary muscle actions, including all body movements and facial expressions.
● Peripheral nervous system – Made up of sensory and motor nerve fibers that connect the peripheral (outer)
parts of the body to the central nervous system. It has both sensory and motor nerves and carries
messages to and from central nervous system.
● Autonomic nervous system – Controls the involuntary muscles; regulates the action of the smooth muscles,
glands, blood vessels, and heart. The autonomic nervous system has two components, the sympathetic
nervous system and the parasympathetic nervous system. The sympathetic nervous system functions like a
gas pedal in a car. It triggers the fight-or-flight response, providing the body with a burst of energy so that it
can respond to perceived dangers. The parasympathetic conserves energy as it slows the heart
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Chapter 2 – Anatomy and Physiology Nervous System
Tip Sheet
rate, increases intestinal and gland activity, and relaxes sphincter muscles in the gastrointestinal tract.
Sometimes called the rest and digest system.
c. Brain – Contained in the cranium
● Largest mass of tissue in the body – Also most complex
● Average weight is 44-48 ounces – Less than 3 pounds
● 12 pairs of cranial nerves – all of which originate in the brain and reach various parts of the head, face, and
neck.
d. Four Parts of Brain
● Cerebrum – Makes up bulk of the brain. Located in front, upper part of cranium. Contains the cerebral
cortex from which most messages from the brain are sent.
● Cerebellum – Latin for Little Brain. Lies at the base of cerebrum and is attached to brain stem. It controls
movements, coordinates voluntary muscular activity, and maintains balance and equilibrium. ● Diencephalon
– Located in uppermost part of midbrain and contains the thalamus and the hypothalamus. The thalamus
acts as a relay station for sensory impulses and plays a role in the recognition of pain and body temperature.
The hypothalamus controls body temperature and pituitary gland.
● Brain Stem – Connects the spinal cord to the brain. Consists of the midbrain, pons, and medulla oblongata,
all of which connect sections of the brain to the spinal cord. It regulates breathing, heartbeat, and blood
pressure.
Tip Sheet
Nervous System – Responsible for coordinating the many activities performed inside and outside the body. Every square
inch of the human body is supplied with fine fibers known as nerves; there are more than 100 billion nerve cells, known
as neurons, in the body.
a. Neurology – The scientific study of the structure, function, and pathology of the nervous system. The nervous
system is one of the most important systems of the body; controls and coordinates the functions of all other
systems, making them work harmoniously and efficiently.
b. Nervous System Divisions
● Central System - Principal parts are the brain, spinal cord, spinal nerves, and cranial nerves. It controls
consciousness and all mental activities, voluntary functions of the five senses (seeing, hearing, feeling,
smelling, and tasting), and voluntary muscle actions, including all body movements and facial expressions.
● Peripheral nervous system – Made up of sensory and motor nerve fibers that connect the peripheral (outer)
parts of the body to the central nervous system. It has both sensory and motor nerves and carries
messages to and from central nervous system.
● Autonomic nervous system – Controls the involuntary muscles; regulates the action of the smooth muscles,
glands, blood vessels, and heart. The autonomic nervous system has two components, the sympathetic
nervous system and the parasympathetic nervous system. The sympathetic nervous system functions like a
gas pedal in a car. It triggers the fight-or-flight response, providing the body with a burst of energy so that it
can respond to perceived dangers. The parasympathetic conserves energy as it slows the heart
, 1
Chapter 2 – Anatomy and Physiology Nervous System
Tip Sheet
rate, increases intestinal and gland activity, and relaxes sphincter muscles in the gastrointestinal tract.
Sometimes called the rest and digest system.
c. Brain – Contained in the cranium
● Largest mass of tissue in the body – Also most complex
● Average weight is 44-48 ounces – Less than 3 pounds
● 12 pairs of cranial nerves – all of which originate in the brain and reach various parts of the head, face, and
neck.
d. Four Parts of Brain
● Cerebrum – Makes up bulk of the brain. Located in front, upper part of cranium. Contains the cerebral
cortex from which most messages from the brain are sent.
● Cerebellum – Latin for Little Brain. Lies at the base of cerebrum and is attached to brain stem. It controls
movements, coordinates voluntary muscular activity, and maintains balance and equilibrium. ● Diencephalon
– Located in uppermost part of midbrain and contains the thalamus and the hypothalamus. The thalamus
acts as a relay station for sensory impulses and plays a role in the recognition of pain and body temperature.
The hypothalamus controls body temperature and pituitary gland.
● Brain Stem – Connects the spinal cord to the brain. Consists of the midbrain, pons, and medulla oblongata,
all of which connect sections of the brain to the spinal cord. It regulates breathing, heartbeat, and blood
pressure.
