THE NERVOUS SYSTEM – CH. 9

Maria Buan, Melissa Jonhson, Jane Long

p.5

The Nervous System Feeling, thinking, remembering,

moving Sends & receives information that

stimulates muscles and glands Brain, spinal cord, neurons, &

nerves

The Nervous SystemSENSORY FUNCTIONS

Involuntary actions Detects changes in

the body Creates sensations Produces thoughts

and memories

MOTOR FUNCTIONS

Voluntary actions Responds to

impulse Muscles & glands Controls skeletal

muscle system

The Nervous System Central Nervous

SystemBrain & spinal

cordIntegrates

information“Control

Center”Retrieved from http://www.umm.edu/ graphics/images/en/19588.jpg

The Nervous System Peripheral

Nervous SystemSensory &

motor neurons throughout body

Receptors and effectors

Retrieved from http://www.clipart.dk.co.uk/ 413/ subject/Biology/Nervous_system

Neurons A specialized cell that transmits

signals throughout the body Cell body

Contains dendrites Contains a nucleus

Retrieved from http://scientopia.org/ blogs/scicurious/2011/05/04/science-101-the-neuron/

Neurons Dendrites

Receives information Axon

directs impulse away Schwann Cells

Cells that wrap around axonProduces myelin

Neurons

Retrieved from http://en.wikipedia.org/wiki/Neuron

Nucleus

Cell BodyDendrites

AxonAxon Terminal

Nucleus of Schwann CellSchwann

Cell

Neurons

Anaxonic MultipolarUnipolarBipolarRetrived from http://iupucbio2.iupui.edu/ anatomy/images/Chapt13/FG13_10.jpg

Retrieved from http://iupucbio2.iupui.edu/ anatomy/images/Chapt13/FG13_10.jpg

Synapse Synapse: A junction between two

neurons where an impulse from one neuron is sent to another

Synaptic cleft: space between two neurons

Synapse Synaptic Transmission:

Neurotransmitters cross synaptic cleft & bind to receptors of other neuron

Retrived from http://scoehealthcoop.wikispaces.com/Neuron+and+Synapse

Synapse Neurons in resting state have

negative charge As impulse move down axon,

negative charges become positive, causing

action potential

Retrived from http://apbrwww5.apsu.edu/t hompsonj/Anatomy

Synapse Action Potential: a rise in the

number of positive ions in a neuron’s membrane that allows impulse to move down axon

Causes impulse to move across synaptic cleft to another neuron

Major Structures of the Brain Cerebrum Diencephalon Brainstem Cerebellum

Retrieved from http://www.sharpbrains.com/blog/2011/11/20/research-on-applied-neuroplasciticy-rewiring-the-brain-to-ease-pain/

Major Structures of the Brain Cerebrum

Made up of two hemispheres

Contains 75% of all neurons

Divided into 4 lobes Retrieved from http://www.mayoclinic.com/

health/medical/IM00317

Lobes of the Brain

Retrieved from http://en.wikipedia.org/wiki/File:Lobes_of_the_brain_NL.svg

Parietal LobeFrontal Lobe

Temporal Lobe

Cerebellum

Occipital Lobe

Brain Stem

Major Structures of the Brain Four lobes of the brain:

Frontal: reasoning, planning, emotions

Parietal: orientation, recognitionTemporal: perception, memory,

speechOccipital: visual processing

Major Structures of the Brain Functions of the Cerebrum

Provides higher brain functionsSensory, motor, & association areasDominant hemisphere functions

better in verbal actions, while nondominant specializes in nonverbal functions

Major Structures of the Brain Diencephalon

Between the hemispheres

Thalamus and hypothalamus

Makes up the limbic system

Retrieved from http://en.wikipedia.org/ wiki/File:Illu_diencephalon_.jpg

Major Structures of the Brain Functions of the diencephalon

Receives all sensory impulsesSensationsMaintains homestasisLimbic system controls emotions

Major Structures of the Brain Brainstem

Bundle of nervous tissue

Includes midbrain, pons, and medulla oblongata

Retrieved from http://sccpsy101.com/home/ chapter-3/section-4/brain_stem/

Major Structures of the Brain Functions of the Brainstem:

Midbrain: eye and head movements

Pons: sends impulses, helps regulate breathing

Medulla Oblongata: contains reflex centers

Major Structures of the Brain Cerebellum

Located at the base of skull

Made of white matter and a thin, outer layer of gray matter

Retrieved from http://neuroscience.uth .tmc.edu/s3/chapter05.html

Major Structures of the Brain Functions of the Cerebellum

Communicates with nervous system

Specializes in positions of body parts and coordination of movements

Maintains posture

Two Nervous SystemsCentral Brain & spinal

cord Processes &

interprets info Sends

information to nerves

Peripheral Cranial & spinal

nerves Sends info to

muscles and organs

Voluntary & involuntary

Autonomic Nervous System Involuntary movements Controlled by PNS Divided into two categories

Sympathetic Parasympathetic

Autonomic Nervous SystemSympathetic Emergency

conditions Leaves spinal

cord Secretes

norepinephrine

Parasympathetic Ordinary

conditions Begins in brain

and spinal cord Secretes

acetylcholine

Somatic Senses Receptors in the skin, muscles &

joints Senses touch, temperature, pain, pressure

Retrieved from http://www.medicalook.com/ human_anatomy/organs/Somatic_senses.html

Somatic Senses Touch and pressure receptors

-Senses mechanical forces that disform tissues

1) Free Nerve-endings• Common in epithelial tissues• Free ends extend between

epithelial cells

Somatic Senses Touch and pressure receptors cont. 2) Meissner’s corpuscles

• Small, flattened connective tissue cells

• Common in hairless parts of the skin• Responds to light touch

Somatic senses Touch and pressure receptors cont. 3) Pacinian Corpuscles

• Large connective tissue fiber & cells• Common in subcutaneous layer,

muscle, tendons & joint ligaments• Responds to heavy pressure

Somatic Senses Temperature senses

Warm receptors-sensitive to 77˚F(25˚C) or higher-unresponsive at & above 113˚F

(stimulate pain receptors)(burning sensation)

Somatic Senses Temperature senses cont.

• Cold receptors-sensitive to 50˚F(10˚C)~68˚F(20˚C)-unresponsive below 10˚C (stimulate pain receptors)(freezing sensation)

Somatic Senses Pain receptors- Distributed throughout the skin &

internal tissues (NOT so much in the brain)

- Once activated, it may send impulses to the CNS.

- Thus, pain may persist.

Olfactory & Taste receptors Chemoreceptors : chemicals

dissolved in liquids stimulate them

We usually smell & taste food AT THE SAME TIME

Olfactory Nerve Olfactory receptor cells (bipolar

neurons) are stimulated by odorant molecules & send nerve impulses.

The fibers synapse with neurons in the olfactory bulbs.

Additional impulses travel along the olfactory tracts to the limbic system.

Taste buds 10,000 taste buds associated

with papillae Taste cells (gustatory

cells)=receptors Every taste bud has 50 ~ 150

receptors

Taste Buds 4 primary taste sensations

-sweet: like sugar-sour: like lemon-salty: like salt-bitter: like caffeine

Taste Buds Taste cell CAN respond to more than

one taste sensation Myth= one region of the tongue

responds to particular sensation

Taste Buds Sensory impulses travel to the

medulla oblongata Ascend to the thalamus and to

the gustatory cortex (parietal lobe)

Taste & Smell Odor and taste information help

create the sensation of flavor Tastants (chemicals in food) and

odor molecules are similarly picked up by the cells

Taste & Smell Taste & smell together detect

flavor Example: sick person with a

stuffed nose cannot taste anything; loses appetite.

Diseases & Disorders Huntington Disease

Disorder of the brain, involuntary movements and personality changes

EpilepsyDisorder in CNS, causes seizures

and loss of consciousness

Diseases & Disorders Cerebral Palsy

Damaged cerebrum, causes partial paralysis/lack of muscle coordination

AphasiaLoss of ability to

use/understand words due to damage in cerebral association areas

Works Cited "Brain Structures and Their

Functions."Serendip Studio. N.p., n.d. Web. 27 Feb. 2013. <http://serendip.brynmawr.edu/bb/kinser

Cherry, Kendra. “What is a Neuron.” About.com Physcology.

 "Anatomy of the Brain - Cerebellum." Biology. N.p., n.d. Web. 27 Feb. 2013. <http://biology.about.com/od/anatomy/p/c

Works Cited "Central Nervous System."Biology. N.p.,

n.d. Web. 27 Feb. 2013. <http://biology.about.com/od/organsystems/ss/central-nervous-system.htm>.

"Organization of the Nervous System." The Peripheral Nervous System. N.p., n.d. Web. 27 Feb. 2013.