Download The Nervous System

The Nervous System
Functions of the Nervous System
 Receive Sensory Input
 Integrate Information (Immediate response, ignore it,
store in memory)
 Control Muscles and Glands
 Maintain Homeostasis
 Mental Activity
Divisions of the Nervous System
 2 major divisions of the nervous system
 Central Nervous System (CNS)
 Brain and Spinal Cord
 Peripheral Nervous System (PNS)
 Nerves and ganglia outside of the CNS
 31 pairs of spinal nerves and 12 cranial nerves
 Functional Subdivisions of the PNS
 Sensory division: (Afferent) PNSCNS
 Motor division: (Efferent) CNS Muscles and Glands
CNS vs PNS
Somatic Motor Nervous System and
Autonomic Nervous System
 Somatic Motor Nervous System
 Voluntary and reflexes
 Autonomic Nervous system
 Involuntary
 Sympathetic Division ( prepares the body for physical
activity)
 Parasympathetic Division (Activates functions of the body
while at rest goes back to normal)
CNS
PNS
Brain & Spinal Cord
Cranial & Spinal Nerves
Sensory Division
Motor Division
(Periphery → CNS)
(CNS → Periphery)
Afferent/Incoming
Efferent/Outgoing
Cranial
Spinal
Nerves
Nerves
Somatic Motor NS
Autonomic NS
Voluntary
Involuntary
(Reflexes)
Sympathetic
Stimulatory
Parasympathetic
Inhibitory
GI
Enteric
Cells of the Nervous System
 Neurons/nerve cells: receive stimuli and transmit action
potentials (send and receive information)
 Cell Body: contains the nucleus and two extensions
 Dendrites: shorter, more numerous, and receives
information (Action Potentials)
 Axons: single, long “fiber” which conducts impulse away
from the cell body, sends information (Action Potentials)
Types of Neurons
 Unipolar: 1 process, a neuron with a single axon
(Sensory, afferent neurons)
 Bipolar: 2 process, one dendrite and one axon
(Special senses, retinal, nasal cavity)
 Multipolar: Several dendrites and one axon (CNS and
all motor efferent)
Neuroglia
 5 types of Neuroglia
 Astrocytes: CNS structural support, create the blood



brain barrier, and tissue repair.
Ependymal: Produce and help circulate cerebrospinal
fluid.
Microglia: Fights infection, and help remove bacteria and
cell debris.
Oligodendrocytes: Found in the CNS and insulation
around axons.
Schwann Cells: Found in the PNS and insulation around
axons.
Neuroglia
Neuroglia
Schwann Cells
Myelinated Axons
 Myelinated Axon: Conducts at a faster rate. Allows the
action potential to jump from nodes of Ranvier.
White vs. Grey Matter
 Myelinated (white matter) – myelinated axons
 Unmyelinated (grey matter) - unmyelinated