Download Organization of the Nervous System

Organization of the
Nervous System
Exercise 18
Main Responsibilities
 Detect changes in and around the body
 Process incoming sensory information and react accordingly
 Orchestrate and integrate all sensory and motor activities
 Ultimate goal  maintain homeostasis
CNS vs. PNS
 Central Nervous System (CNS)  brain and spinal cord
 Peripheral Nervous System (PNS)  communicates with CNS via cranial and spinal nerves
Peripheral Nervous System
 Afferent Division
 RECEIVES sensory information and then sends the information to the CNS for processing
 Motors responses are generated and PNS carries our the demands via the….
 Efferent Division
 CARRIES OUT the responses to sensory information
 Controls the activities of “effectors” (muscles and glands of the body)
 Somatic Nervous System (conducts motor responses to skeletal muscles)
 Autonomic Nervous System (sends commands to the visceral effectors)
 Sympathethic
 Parasympathetic
PNS Nerves
 Cranial Nerves
 Communicate with the brain
 Pass into neck and face through the foramina in the skull
 Spinal Nerves
 Join spinal cord at intervertebral foramina
 Pass into upper and lower limbs of the body
 “Mixed” – carry BOTH sensory and motor signals
A Closer Look @ Nervous System Cells
 GLIAL CELLS– support, protect, and maintain nerve tissue
 Most abundant cells in the nervous system
 CNS  production and circulation of cerebrospinal fluid (CSF)
 2 types (PNS)
 Satellite Cells
 Schwann Cells
 4 types (CNS)
 Oligodendrocytes  form myelin sheath
 Microglia  remove microbes and cellular debris from CNS tissue
 Ependymal  line the ventricles of the brain and central canal of the spinal cord
 Astrocytes  maintain the blood brain barrier (BBB), structural support, regulate ion content, and repair
A Closer Look @ Nervous System Cells
 NEURONS - communication cells
 Components: dendrites, cell body, axon
 Nissl bodies: groups of free ribosomes and RER
Telodendriad
Anatomy of the Nerve
 Three membranes:
 Epineurium – Outer layer
 Perineurium – Separates axons into fassicles
 Endoneurium – Surrounds each axon
https://www.youtube.com/watch?v=TKG0MtH5crc
Extra Credit – 5 BP towards exam
 Chapter 13 OR Chapter 7