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Human Nervous System

1/14/2015

IntroductionThe Human Nervous System is

comprised of two sections: The

Central Nervous System and the

Peripheral Nervous System. The

combination of the efforts of both of

these systems allow us to analyze

and sense changes inside or outside

of our bodies, while simultaneously

allowing us to respond and react to

these changes.

Human Nervous SystemThe Human Nervous System can

be compared to the nucleus in a

eukaryotic cell. It controls

processes within the body,

responds to internal and external

situations, and manages the body.

Overall, the human nervous

system is composed of the brain,

the spinal cord, spinal nerves,

cranial nerves, and sensory organs

and receptors.

Central Nervous SystemThe Central Nervous System is located in

the center of the body and receives

information from sensory organs from the

Peripheral Nervous System and

analyze/interprets the information. In

response, the Central Nervous System also

reacts with signals and movements through

the Peripheral Nervous System,

inadvertently or purposefully.

This system, in addition to the Peripheral

Nervous System, is made of specialized

nerve cells called neurons.

Parts of the Central Nervous SystemSpinal Cord: located in the center

of the back of the torso, the spinal

cord is surrounded by nerves from

the Peripheral Nerve System.

Brain: located in the back and the

upper front of the head, the brain

contains billions of neurons that

transmit, carry, and contain

information that control response.

Parts of the BrainThe brain itself is

made of four main

parts: the cerebrum,

the cerebellum, the

diencephalon, and the

brain stem. The

cerebrum contains 85

percent of the brain’s

matter. These four

parts are connected to

senses and bodily

movements.

NeuronsNeurons are specialized cells that are

specifically shaped to service the

nervous system. They can receive,

respond, send/transmit, and/or analyze

information that is being sensed.

Interneurons are specifically found in

the CNS and respond to information that

is sent their way. Afferent Neurons and

Efferent Neurons are found in the

Peripheral Nervous System. These

neurons send automatic impulses to the

CNS

NeuronsNeurons are built like a normal eukaryotic cell, with a nucleus

in the center. A series of “branches” grow outwards from the

nucleus. The main extension is called the axon. It carries

messages that leave the cell. Dendrites are smaller branches

upon main branches to pass on electrical signals, in addition to

information. A layer of phospholipids called the myelin sheath

increase the cell’s ability to carry the electrical signals that

pass between the nervous systems.

Peripheral Nervous SystemThe Peripheral Nervous System is located

throughout the body. Sensory organs,

receptors, internal organs, and muscles are

some parts of this system. The Peripheral

Nervous System spreads outwards from the

CNS. Each of the thirty-one spinal pairs of

nerves contains a dorsal root and a ventral root

that will relay the instructions to muscles and

organs. Afferent neurons in the head carry

information from the CNS through twelve

cranial pairs of nerves. The Peripheral Nervous

System contains the Somatic and the

Autonomic Nervous Systems. Together, they

respond to stimuli and maintain homeostasis.

Somatic Nervous System

The Somatic Nervous System is

also called the Voluntary

Nervous System, whereas the

Autonomic Nervous System is

the Involuntary Nervous System.

Compared to the Autonomic

Nervous System, the SNS works

consciously and purposefully.

This nervous system contains

the 31 pairs of spinal nerves and

12 pairs of cranial nerves.

Smiling is a voluntary movement

Autonomic Nervous SystemThe Autonomic Nervous System

is also called the Involuntary

Nervous System. It maintains

homeostasis and works

automatically and unconsciously.

This nervous system contains

receptors, sensory/internal

organs, and smooth/cardiac

muscles. The organs and

receptor send information

through efferent neurons while

muscles and organs carry out

the impulses.

Fight or Flight is a sympathetic reaction where a sense of panic is achieved.

Parasympathetic reactions inversely achieve a state of calm.

Diseases in the Human Nervous System

Many different diseases can occur

within the nervous system that affect

the human body and its capabilities.

Alzheimer’s disease, epilepsy,

Huntington disease, Parkinson’s

disease, and aphasia are some

diseases that occur in this system.

Diseases can be genetic or caused by

trauma or injury(autoimmune

disorders, disruption of the normal

blood flow, tumors, or infection).

Aphasia

Aphasia is the loss or inability of

speech. When someone suffers

from aphasia they can have

difficulties understanding other

people when they speak. They

can also find that they have

difficulty speaking or finding

words. If the brain has suffered

from a severe injury or they have

suffered a stroke, these

disabilities can occur.

Epilepsy

Epilepsy is a disease where

the patient can suffer

seizures or convulsions in

varying states of severity

and durations of time,

depending on the

individual’s situation.

Children can develop

epilepsy if they suffer from

a high fever. This condition

can occur at any age.

Strobe lights can result in seizures in those who suffer from epilepsy.

ConclusionWhile I was researching this presentation, I found

many facts on the many parts of the Human

Nervous System that I did not previously know. For

example, I did not know about the myelin sheath on

neurons that promote conductivity. I also learned

more about aphasia, epilepsy, and diseases in the

Human Nervous System. This activity benefited me

by prompting me to learn more about this body

system. Overall, I learned about the function of the

Human Nervous System, the types of impulses that

control responses, and the different components of

the system.

CitationsClip Art

" Human Nervous System." The Human Nervous System. Biology Online, n.d. Web. 11 Jan. 2015.

 "Nervous System Diseases." Des Moines University. Des Moines University, n.d. Web. 11 Jan. 2015.

 "Nervous System." PennMedicine. Adam, 2001. Web. 11 Jan. 2015.

"Overview of Nervous System Disorders." JohnsHopkinsMedicine. JohnsHopkins, n.d. Web. 11 Jan. 2015.

"What Are the Parts of the Nervous System?" NICHD. NICHD, 9 Apr. 2014. Web. 11 Jan. 2015.