fight or flee

Fight or Flee?

Artifact 2

Central Nervous System

© “Visible Body.” Argosy Publishing, Inc. 2007-2012 <http://www.visiblebody.com>

The Meninges


The Meninges

• Function: The dura mater- is the outer layer.

Like its name implies, it surrounds the brain

and spinal cord, providing a layer of durable,

tough, and inelastic protection. The arachnoid

membrane- lies just below the dura mater. It

resembles a matrix of spider webs, and hence

the name. The pia mater- is the layer closest

to the brain and spinal cord. It is actually

intimately close to the brain and spinal cord

The CSF and Spinal Chord

• Function of CSF: : Cerebrospinal fluid has three important, life-sustaining

functions: 1) to keep the brain tissue buoyant, acting as a cushion or "shock

absorber"; 2) to act as the vehicle for delivering nutrients to the brain and

removing waste; and 3) to flow between the cranium and spine to

compensate for changes in intracranial blood volume (the amount of blood

within the brain).

• Where is it found? located between the brain and skull.

• Function of Spinal Chord: : Structurally, the cord is a double-layered tube,

roughly cylindrical in cross section. The outer layer consists of white matter,

i.e., myelin-sheathed nerve fibers. The inner layer, or gray matter, is primarily

composed of nerve cell bodies.

• Where is it- The spinal cord is contained within the spine, extending from the

base of the skull to the second lumbar vertebra at the base of the spine.

• Shape- the spinal cord has a shape that is compressed dorso-ventrally, giving

• Nerve Roots:The nerve roots run through the bony canal, and at each level a

pair of nerve roots exits from the spine.

Spinal Chord


Brain Stem


Cerebellum


Thalamus & Hypothalamus


Cerebral Cortex

Thin layer of grey matter made up of neuron dendrites and cell bodies that compose

the surface of the cerebrum.

N.d. n.p. Web. 5 Nov 2012.

<http://www.memorylossonline.com/glossary/images/cerebralcortex.jpg>.

Peripheral Nervous System


Spinal Nerves

N.d. n.p. Web. 5 Nov 2012.

<http://www.medicalook.com/human_anatomy/organs/Spinal_nerves.html>.

Nerve Plexus

https://www.youtube.com/watch?v=cGJKgPUQh

nI&feature=youtube_gdata_player

Brief video description of the spinal nerves,

what they lead to and where they are located.

Dermatomes and Myotomes

• Spinal nerves have motor fibres and sensory fibres. The motor fibres innervate certain muscles, while the sensory fibres innervate certain areas of skin. A skin area innervated by the sensory fibres of a single nerve root is known as a dermatome. A group of muscles primarily innervated by the motor fibres of a single nerve root is known as a myotome. Although slight variations do exist, dermatome and myotomepatterns of distribution are relatively consistent from person to person.

© 2003 - 2012 Apparelyzed.com

Cranial Nerves


Cranial Nerves

• Cranial Nerve: Major Functions:

• I Olfactory smell

• II Optic vision

• III Oculomotor eyelid and eyeball movement

• IV Trochlear innervates superior oblique, turns eye downward and laterally

• V Trigeminal chewing, face & mouth touch & pain

• VI Abducens turns eye laterally

• VII Facial controls most facial expressions , secretion of tears & saliva, taste

• VIII Vestibulocochlear (auditory) hearing, equillibrium sensation

• IX Glossopharyngeal taste , senses carotid blood pressure

• X Vagus senses aortic blood pressure, slows heart rate, stimulates

digestive organs, taste

• XI Spinal Accessory controls trapezius & sternocleidomastoid, controls swallowing movements

• XII Hypoglossal controls tongue movements

• Created and copyrighted © J. Crimando Ph.D. GateWay Community College; Phoenix, AZ Originally created: Fall, 1997.

Last modified: Spring, 2012

Afferent and Efferent Nerves

N.d. n.p. Web. 5 Nov 2012. <http://www.getbodysmart.com/ap2/nervoussystem/organization/sensorymotor/tutorial.html>.

Autonomic Nervous SystemThe organs (the "viscera") of our body, such as the heart, stomach and intestines, are regulated by

a part of the nervous system called the autonomic nervous system (ANS). The ANS is part of the peripheral nervous system and it controls many organs and muscles within the body. In most situations, we are unaware of the workings of the ANS because it functions in an involuntary, reflexive manner. For example, we do not notice when blood vessels change size or when our heart beats faster. However, some people can be trained to control some functions of the ANS such as heart rate or blood pressure.

The ANS is most important in two situations:

In emergencies that cause stress and require us to "fight" or take "flight" (run away)

In nonemergencies that allow us to "rest" and "digest."

The ANS regulates:

Muscles

-- in the skin (around hair follicles; smooth muscle

-- around blood vessels (smooth muscle)

-- in the eye (the iris; smooth muscle)

-- in the stomach, intestines and bladder (smooth muscle)

-- of the heart (cardiac muscle)

Glands

The ANS is divided into two parts:

The sympathetic nervous system

The parasympathetic nervous systemSource 5

Somatic System

© 2

The somatic senses include sensations of touch, pressure, temperature, body

position, and similar perceptions that do not require complex sensory organs, like

vision and hearing.

Sympathetic Nervous System


Sympathetic Nervous System

• the sympathetic nervous system originates in the spinal cord. Specifically, the cell bodies of the first neuron (the preganglionic neuron) are located in the thoracic and lumbar spinal cord. Axons from these neurons project to a chain of ganglia located near the spinal cord. In most cases, this neuron makes a synapse with another neuron (post-ganglionic neuron) in the ganglion. A few preganglionic neurons go to other ganglia outside of the sympathetic chain and synapse there. The post-ganglionic neuron then projects to the "target" - either a muscle or a gland.

Source 5

Parasympathetic Nervous System

• The cell bodies of the parasympathetic nervous system are located in the spinal cord (sacral region) and in the medulla. In the medulla, the cranial nerves III, VII, IX and X form the preganglionic parasympathetic fibers. The preganglionic fiber from the medulla or spinal cord projects to ganglia very close to the target organ and makes a synapse. This synapse uses the neurotransmitter called acetylcholine. From this ganglion, the post-ganglionic neuron projects to the target organ and uses acetylcholine again at its terminal.

Citations

1. Thibodeau PhD, Gary A. Anthon'ys Textbook of Anatomy and Physiology. Seventeenth. St. Louis, Missouri: Mosby, 2003. Print.

2. “Visible Body.” Argosy Publishing, Inc. 2007-2012 http://www.visiblebody.com

3. gary , farr. "The Nervous System - Advanced Version / The Meninges ." becomehealthynow.com. gary farr, 24 2002. Web. 29 Oct 2012.

4. garry, farr. "The Spine / The Spinal Cord & Nerve ." becomehealthynow.com. gary farr, 14 2012. Web. 29 Oct 2012.

5. Copyright © 1996-2011, Eric H. Chudler, University of Washington

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