Nervous System, the Brain, and the Sensory Organs

Functions of the Nervous System

1. Sensory input is the gathering information to monitor changes (__________) occurring inside and outside the body

2. Integration occurs when your body processes and interprets __________ input and decides if action is needed.

3. Motor output is a response to integrated stimuli that activates ______________ or _____________

Structural Classification of the Nervous System

• The central nervous system (CNS) is comprised of the _____________ and _________________.

• The peripheral nervous system (PNS) is comprised of the nerves __________ the brain and spinal cord.

Organization of the Nervous System

The nervous system’s basic unit is the ______________ (Nerve Cell). These cells are specialized to

______________ messages. The neuron has 2 major regions: the cell body that consists of the _____________, a

large _______________, and is the ________________ center of the cell, and the _______________, which are

the fibers that extend from the cell body (____________ - which conduct impulses toward the cell body, and

_____________ - which conduct impulses away from the cell body).

__________________ _____________________

__________________ _____________________

_____________________

__________________ _____________________

_____________________

________________(covering)

Functional Classification of the PNS

• The sensory (afferent) division

consistes of nerve fibers that carry

information __________the CNS.

• The motor (efferent) division consists

of the nerve fibers that carry impulses

______________ the CNS; there are

__________ subdivisions: the

_______________ nervous system,

which is the _______________ part of

the ______________ part, and the

________________ nervous system,

which is the ________________ part.

Neuron Cell Body Location

• Most are found in the ___________nervous system

• ____________ matter consists of cell bodies and

_______________ (not insulated) fibers

• Nuclei are clusters of cell bodies within the

_______________ matter of the CNS

• _______________ are collections of cell bodies

outside the CNS

Functional Classification of Neurons

• There are 2 types of neurons.

• ______________ (afferent) neurons carry

impulses from the ____________ receptors. They

are the _____________ (skin) sense organs. The

________________ detect stretch or tension in

the skin.

• ____________ (efferent) neurons carry impulses

from the _____________.

The Reflex Arc

A reflex is a ____________, _____________, and

_________________ responses to stimuli.

A reflex arc is the direct route from a ___________

neuron, to an ______________, to an ____________,

which will be a muscle or gland.

Somatic reflexes result in the activation of

_________________________.

Types of Reflexes and Regulation

Simple Reflex Arc

Central Nervous System (CNS)

The CNS develops from the _______________ neural tube, which becomes the ____________ and

___________________. The opening of the neural tube becomes the _______________ (brain chambers). There

are ______ chambers within the brain that are filled with ___________________ fluid.

There are 4 regions of the brain. They are _________________, ___________________, _________________,

and ____________________. Each of these regions is subdivided into ______________.

Autonomic reflexes are involved in _____________

muscle regulation, such as _____________ and

_______________________ regulation, regulation

of ______________, and ______________ system

regulation.

Cerebral Hemispheres (______________)

are paired (left and right) superior parts of

the brain that include ____________ half of

the brain mass, has its surface made of

______________ (gyri) and ___________

(sulci), and has ____________ that divide

the cerebrum into lobes.

There are _____ surface lobes of the

cerebrum; they are the ____________,

_____________, _______________, and

_____________ lobes.

There are many specialized areas of the brain.

Three of these are (1) the _________

sensory area receives impulses from the

body’s sensory receptors, (2) the _________

motor area sends impulses to skeletal muscles,

and, (3) the __________ area is involved in

our ability to speak.

Specialized Areas of the Cerebrum

The cerebral areas involved in special senses are the __________ area (taste), the ____________ (sight)

area, _______________ (hearing) area, and ________________ area (smell).

Interpretation areas of the cerebrum

The brain has many specialized regions with very specific jobs. Three of these are the ___________________

region, the ______________________________ region, and the __________________________ region.

The brain stem attaches to the __________________. It is divided into 3 regions: (1) ________________, (2)

_______________, and _______________________.

The midbrain is composed of _____________ of nerve fibers. It has the reflex centers for ______________ and

_______________. It also contains the cerebral aquaduct which connects the 3rd and 4th ______________ to allow

flow of ______________________.

The pons is the bulging ____________ part of the brain stem, mostly composed of fiber tracts, that includes nuclei

involved in the control of _________________.

The medulla oblongata is the _____________ part of the brain stem, that merges into the __________________,

includes important fiber tracts, and contains important control centers for _________________ control,

_______________________ regulation, ________________, _____________________, and _____________.

The ______________ has 2 hemispheres with convoluted surfaces (folds). It provides_____________ coordination

of body movements.

Protection of the CNS

The CNS is protected by multiple levels of protection. These include _____________ and _____________,

_____________, ___________________fluid, and the _____________________ barrier.

There are many conditions that impact the brain. These include Traumatic Brain Injuries (TBI), Cerebrovascular

Accidents (CVA), Alzheimer’s Disease (which is actually a disorder), and Spinal Cord Injuries.

TBIs include (1) ______________, these are slight or mild brain injury with bleeding & tearing of nerve fibers where

recovery is likely with some memory loss; and, (2) ____________________, which are a more severe TBI with

nervous tissue destruction where the nervous tissue does not regenerate.

CVAs include (1) ___________________ where there is swelling of the brain from an inflammatory response that

may compress and kill brain tissue; and (2) ________________ that results in collection of blood below the dura

(this is a bruise on the brain). These are commonly called a ____________ because they result of a ____________

blood vessel supplying a region of the brain causing the brain tissue supplied with oxygen from that blood source to

__________. There will be loss of some functions or death may result.

Alzheimer’s Disease is a progressive ______________ brain disorder that is mostly seen in the ____________, but

may begin in middle age. It results in structural changes in the brain that include abnormal _____________ deposits

and twisted fibers within neurons. Victims experience ____________________, ____________________,

________________, and ultimately, _______________________ and _________________.

SCJs extend from the __________________ to the ___________ region of the spinal cord. Below T12 is the

__________________________ (a collection of spinal nerves). Enlargements occur in the _____________ and

________________ regions. These may result in great pain, loss of mobility, or paralysis.

The Peripheral Nervous System consists of nerves (bundles of ___________________) and ganglia

_______________ the CNS. Neuron fibers are bundled together by _______________ tissue that strengthens

and insulates the neurons.

Spinal nerves always come in ______________ at the level of each vertebrae. The spinal nerves connect the CNS to

all of the other areas of the body.

The Autonomic Nervous System is the _________________ branch of the nervous system consisting of only

______________ nerves. It is divided into two divisions: the ____________________ division and the

____________________ division. The sympathetic – “fight-or-flight” – division is the _________________ to an

unusual _________________ that takes over to _______________ neural activities. You can easily remember this

division as the “E” division = _________________, __________________, ___________________, and

_____________________.

The ___________________ division – housekeeping activities – helps the body ________________ energy by

_________________ the necessary daily body functions. You can easily rememeber this division as the “D” division -

___________________, ____________________, and ______________ (urination).

EXAMPLE of Response EXAMPLE of Response

blinking to remove dust crying due to stress__

_________________ _________________

_________________

_________________

_________________ _________________

_________________

_________________ _________________

_________________ _________________

_________________ _________________

_________________ _________________

_________________ _________________

Comparison of Somatic and Autonomic Nervous Systems

The rod cells are not sensitive to color, but have _______________ sensitivity to light than the cone cells. Rods are

located around the fovea and are responsible for _________________ (side) vision and _______________ vision.

The eye is connected to the brain through the ______________ nerve. The point of this connection is called the

"__________________" because it is insensitive to light. Experiments have shown that the back of the brain

(____________________) maps the visual input from the eyes. Being nearsighted or farsighted depends on the

______________ of your eye. People with blue eyes all share a common ________________. Your eyes actually see

everything upside down, but your brain sorts it out and flips it over for you. Your eyes can get sunburned too. We blink

_____________ times per day. 20/20 vision isn't perfect vision, it's just ________________. The human eye can

detect over ____________ different colors.

The ear is the organ of____________. The outer ear

protrudes away from the head and is shaped like a ______

to direct sounds toward the _________ membrane, which

transmits vibrations to the ________ ear through a series

of small bones in the middle ear called the ___________,

___________ and ______________. The inner ear,

or ____________, is a spiral-shaped chamber covered

internally by nerve fibers that react to the vibrations and

transmit impulses to the brain via the ____________ nerve.

The brain combines the input of our two ears to determine

the _____________ and _____________ of sounds.

The eye is the organ of ___________.

It has a complex structure consisting

of a ____________ lens that focuses

light on the ______________, which

is covered with two basic types of

light-sensitive cells-___________ and

color-sensitive cells - ____________.

The cone cells are sensitive to color

and are located in the part of the

retina called the _____________,

where the light is focused by the

_____________.

Your ears contain the three _____________ bones in the human body: the malleus, incus, and stapes. Ears help the

body maintain ___________________. The outside of the ear is called the ____________ which acts as a funnel,

collecting and amplifying sound for the inner ear. Your ability to hear high frequencies deteriorates as you get older,

because the hair cells closest to your outer ear begin to break down. Sound travels at roughly _______ miles per hour

through our atmosphere. Sound travels faster through more dense substances. ____________ is used to catch dirt

and debris. The hardest bone in the human body is the ______________ bone and it shapes the inner ear where its

shape helps process sounds in the ear.

The receptors for taste, called taste buds, are situated chiefly in the Label this diagram.

tongue, but they are also located in the roof of the mouth and near

the pharynx. They are able to detect six basic tastes: _________,

___________, ____________, ____________, astringent and

pungent. The tongue also can detect a sensation called "umami“

from taste receptors sensitive to amino acids (pungent). Generally, the

taste buds close to the ____ of the tongue are sensitive to sweet tastes,

whereas those in the ______ of the tongue are sensitive to bitter tastes.

The taste buds on ____ and on the _______ of the tongue are sensitive

to salty and sour. Your taste buds have a lifespan that can last from

___ days to _____ weeks. It is possible to kill your taste buds by burning

your tongue, but they ____________ (grow back) rather quickly. However,

smoking can actually reduce taste bud “pods” (called papillae) and therefore dull your taste buds more ___________.

Taste buds are made up of ___________, which are microscopic hairs that send signals to the brain to tell us how to

process and identify how things taste. Your taste buds need the help of your nose’s _____________ senses to send

the correct message to the brain about how something tastes. The flavor of something is determined by the taste and

the smell senses. When you smell an odor you are also ______________ it.

salty salty

astringent

bitter bitter bitter

pungent

sour sour

sweet

The nose is the organ responsible for the sense of ____________. The cavity of the nose is lined with

___________ membranes that have smell receptors connected to the ____________ nerve. The smells themselves

consist of _____________ of various substances. The smell receptors interact with the molecules of these vapors

and __________ the sensations to the brain. The nose also has a structure called the ______________ organ whose

function is being sensitive to pheromones that influence the reproductive cycle. The sense of smell is sometimes

temporarily lost when a person has a _________. The sense of smell comes about through the stimulation of

specialized cells in our nasal cavities — cells that are similar to the sensory cells of the __________ of invertebrates

(like cockroaches and lobsters). The human olfactory system works when odorant________________ bind to specific

sites on the olfactory ______________, which are used to detect the presence of smell. It all comes together at

the ______________, a structure which transmits signals to the olfactory bulb — a part of the brain directly above

the nasal cavity and below the _____________ lobe. The end result is the ________________ (individualized)

experience we call smell. The smell receptors are sensitive to ___________ types of sensations that can be

characterized into 10 categories:

___________________(e.g. florals and perfumes) ___________________(all non-citrus fruits)

___________________(e.g. lemon, lime, orange) ___________________(e.g. pine or fresh cut grass)

___________________(e.g. ammonia, bleach) ___________________(e.g. chocolate, vanilla, caramel)

___________________(e.g. eucalyptus and camphor) ___________________(e.g popcorn, peanut butter, almonds)

___________________(e.g. blue cheese, cigar smoke) ___________________(e.g. rotting meat, sour milk)

The sense of _______ is distributed throughout the body.

Nerve endings in the skin and other parts of the body

________ sensations to the brain. Some parts of the body

have a larger number of nerve endings and, therefore, are

________ sensitive. Four kinds of touch sensations can be

identified: ________, ________, ________, and ________.

________ on the skin magnify the sensitivity and act as an

early warning system for the body. The sense of touch is the

first to develop in humans at about ___ weeks into the

gestation (formation in the uterus) period. Touch stimulates

the brain to release ________________. The skin is your

body’s largest organ and contains more than _____________

sensory receptors. Among the body’s most sensitive areas are

the ________, the back of the ________,

the ________________, and the ________ of the feet. The least sensitive area of your body is the ________ of

your back. Being touched can ________ stress, by lowering levels of hormones like ________, which can reduce

________________ and ________________. ________ is the body’s warning system and that’s why people have

more receptors for pain than for any other sensations. ________________________ perceive sensations related to

temperature, but they may be stimulated when the surface of the skin drops below ____°F (which is why your skin

starts to feel numb in icy temperatures) or rises above ____°F (at which point pain receptors take over to avoid

burns).

Adipose tissue is another

name for this layer because it is

composed of lipids (fats).

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