The Organization of the Nervous System.ppt
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Transcript of The Organization of the Nervous System.ppt
The Organization of the Nervous System
Appearance by color of tissue
• Gray matter -
Appearance by color of tissue
• Gray matter –
• White matter –
Appearance by color of tissue
• Gray matter –
• White matter –
• Reticular matter -
Description by location
• Dorsal to ventral
Description by location
• Dorsal to ventral
• Anterior to posterior
Description by location
• Dorsal to ventral
• Anterior to posterior
• Medial to lateral
General Divisions of the Nervous System
• Central Nervous System– Brain– Spinal Cord
General Divisions of the Nervous System
• Peripheral Nervous System– Somatic
• Sensory (afferent) and Motor (efferent) neurons• Innervates muscles, bones
General Divisions of the Nervous System
• Peripheral Nervous System– Autonomic
• Innervates glands and smooth muscles like the heart
• Works outside our control• Broken into sympathetic and parasympathetic
nervous systems
Sympathetic and parasympathetic nervous systems
• Sympathetic– Charges the body up
for emergencies– All parts emerge
simultaneously– Examples
• Parasympathetic– Calms the body down
after an emergency– A few parts slow down
at a time after an emergency
– Examples
Comparative Approach to Brain Analysis
• Also called the triune brain model– Reptilian – Brainstem made up of medulla
oblongata, pons and cerebellum– Old Mammalian – limbic system made up of
septum, hippocampus; amygdala, cingulate cortex, hypothalamus, and thalamus
– New Mammalian – cerebral cortex
Localization of Brain Function
• Overall, most activities in the brain come from various regions, yet certain activities seem to be most critical in handling specific functions.
Subcortical areas– (from posterior to anterior regions)
• Medulla oblongata• Pons• Cerebellum• Midbrain• Thalamus• Hypothalamus• Limbic system
– Septum– Amygdala– hippocampus
The Neocortex
• Convoluted surface has 10% of our neurons, and 80% of our brain volume– Gyri– Sulci– Fissures
• Responsible for higher functions such as thought and planning
Lobes of the Neocortex• Frontal
– Motor cortex– Broca’s area
• Parietal– Somatosensory region
• Occipital– Primary visual cortex
• Temporal– Wernicke’s area– Smell and taste areas– Auditory cortex
Lateralization of Function
• Techniques for showing lateralization– Electrical stimulation of awake participants– PET scans show regions for different activities– Strokes, injuries and lesions show specific deficits– EEG patterns– Split brain (commissurotomy) patients– Drugs affecting half the brain– Dichotic listening (different noises to each ear)
Left Brain Specialization
• Speech and language– Receptive auditory language function– Expressive language function– Handedness and language
Right Brain Specialization
• Spatial functions• Pattern recognition• Color distinctions• Musical functions
The Endocrine System
• Comparison to nervous system:– Hormones secreted into bloodstream rather
than neurotransmitters secreted into neural pathways
– Works in minutes to hours whereas nervous reactions are fractions of second to minutes
– Long-lasting effects rather than quick to dissipate
– Both interact with specific receptor sites– Systems overlap in certain parts
Hormones
• Three types: – Steroids– Peptides– Amino acid derivatives
Hormones
• Active in small amounts• Under tight negative feedback control• Rapidly degraded in body
– Steroids and peptides in liver– Amino acids by enzymes in blood
Specific Endocrine Glands• Pineal gland• Hypothalamus• Pituitary gland• Thyroid gland• Parathyroid glands• Adrenal glands• Pancreas• Ovaries and testes• *prostaglandins