CENTRAL NERVOUS SYSTEM

Brain Dominance

• Right Brain– non-verbal

– Concrete

– Holistic (big pic)

– Intuitive

– spontaneous

• Left Brain– Logical

– Language

– Verbal

– Sequential/linear (Math)

– Abstract…math/science

– Planner

http://www.web-us.com/BRAIN/braindominance.htm

Objectives

• To learn protective parts/features of CNS

• To learn structure and function of the Spinal Cord

• To understand the brain structure and function as well as development.

Protection of the CNSProtection of the CNS

• Bones

• Meninges

Protection of the CNSProtection of the CNS

• The brain & spinal cord are protected by bones, membranes, and fluid

A. BonesBones

–*8 skull bones encase the brain

–*30 vertebrae encase the spinal cord

Can you name the bones?

– B.) Meninges Meninges - Membranes surrounding CNS

• 3 Layers encasing the brain

–a.) Dura mater

»outermost membrane: attached to periosteum of the skull

»contains many blood vessels & nerves

»tough, white fibrous connective tissue

–b.) Arachnoid Mater

»middle layer

»thin net-like membrane

»No blood vessels

»Sub-arachnoid space lies deep to this layer and is filled with CSF which serves as a cushion for brain

–c.) Pia Mater

»inner layer that clings to brain surface

»very thin delicate connective tissue

»many nerves & blood vessels = nourishment

»dips into grooves and contours inner layer that clings to brain surface

Meningitis

• What does the word Mean?• Caused by:

– Bacteria or virus

• Affects:– Mainly arachnoid and pia maters– Younger or older generations– People with suppressed immune systems

• Complications of disease:– Loss of vision, hearing paralysis, mental

retardation…death

http://upload.wikimedia.org/wikipedia/commons/f/fd/Streptococcus_pneumoniae_meningitis%2C_gross_pathology_33_lores.jpg

C. Ventricles – Interconnected cavities within the cerebral hemispheres

and brain stem

– Continuous with central canal of spinal cord

– Filled with CSF cerebral spinal fluid

– D. Cerebrospinal Fluid (CSF)– Secreted by Choroid Plexus

– Circulation: Ventricles 1&2 --> 3rd --> 4th --> central canal --> reabsorbed into bloodstream

– Approx. 1 liter is secreted daily: Secreted and reabsorbed continuously

– Functions: cushion & circulation of nutrients/wastes

The BrainStructures and Functions

Brain Lobes

Forebrainprosencepahlon

• Includes hypothalamus, thalamus and cerebrum

Midbrainmesencephalon

• Connects cerebrum to spinal cord

• Reflex center for eye and some head movements

Hindbrainrhombencephalon

• Cerebellum

• Medulla oblongata

• Pons

Cerebrum• Largest part of brain

• Contains many folds and bumbs– Sulci vs. gyri

• Corpus callosum is found b/t the L and R

• Responsible for reasoning, intellectual fxn and critical thinking

Brain Dominance

• Right Brain– non-verbal

– Concrete

– Holistic (big pic)

– Intuitive

– spontaneous

• Left Brain– Verbal

– Sequential/linear

– Abstract…math/science

– Logical

– Planner

http://www.web-us.com/BRAIN/braindominance.htm

Cerebral Cortex

• Thin layer (2-5mm); largest and most anterior structure of brain

• Contains 75% of neuron cell bodies in NS

• Memory, attn, thought processes, language

cerebellum

• Regulates balance

• body position

• Posture

• Muscle coordination

Medulla oblongata

• Vital Reflex center

– Visceral activities:

– blood pressure, respiratory

– cardiac

• Part of the brain stem

• Injuries often fatal

Corpus callosum• Deep bridge of

nerve fibers• Connects L and R

brain• Intercommunication

b/t hemispheres is not completely understood

Optic chiasma

Limbic System

Limbic

• Includes the hypothalamus, hippocampus, amygdala

• Important in emotions and formation of memories

Limbic

• Hypothalamus• Part of diencephalon• Secretes hormones

– Dopamine, oxytocin, growth hormones

• Regulates body temp, heart rate, hunger/weight, alertness

• Center involved with emotion

Thalamus• Part of diencephalon• Motor control• Receives visual and

auditory senses

Pineal gland

• Produces melatonin; controls circadian rhythm

• Size of a pea; 8mm

• Think about it…– Stimulated by dark

– Inhibited by light

c

Pineal body

Pituitary gland

• Endocrine gland; secretes hormones

• Examples– growth hormones;

– regulate breast milk production; sexual hormones

– possibly blood pressure

Pons

• b/t midbrain and medulla oblongata

• Regulates rate and depth of breathing

• Homeostatic mechanisms

Mammillary body

• Named for resemblance of 2 breast

• Associated with memory

• Damaged by alcoholic intoxication

Hippocampus

• Part of limbic system• Emotions, inhibition

• Long term memory• Alzheimer’s disease

– First to be damaged

If damaged, what do you predict would be the results?

Reticular formation

• Brainstem and diencephalon

• Alertness, arousal, sensory integration, motivation

• connects to areas in the thalamus, hypothalamus, cortex and cerebellum

http://www.web-us.com/BRAIN/braindominance.htm