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

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 CNS Bones Meninges

Protection of the CNS The brain & spinal cord are protected by bones, membranes, and fluid Bones A. Bones –*8 skull bones encase the brain –*30 vertebrae encase the spinal cord

Can you name the bones?

Meninges –B.) 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 –erves & blood vessels = nourishment»dips into grooves and contours–erves & blood vessels = nourishment»dips into grooves and contours

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

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 Brain Structures and Functions

Brain Lobes

Forebrain prosencepahlon Includes hypothalamus, thalamus and cerebrum

Midbrain mesencephalon Connects cerebrum to spinal cord Reflex center for eye and some head movements

Hindbrain rhombencephalon 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

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