Nervous and Endocrine System

one of the smallest systems, but most complex

it depends on electrical activity

Control and adjust activities of other systems.

Use Chemical communication

Nervous System - rapid but brief responses

Endocrine - slower but often lasts much longer

Sensory Input - mnitoring stimuli occuring inside and outside the body

Integration - interpetation of sensory input

Motor output - response to stimuli by activating effector organs

• CNS Central nervous System
• *Brain and Spinal Cord
• *Integrating, processing and coordinating
• *Intelligence, memory, learning and emotion

• PNS Peripheral Nervous System
• *Provides sensory information to the CNS
• *Carries motor commands to peripheral tissues

The Afferent division of the PNS brings sensory information to the CNS

The Efferent division carries motor commands to the muscles and glands

• *The efferent division is divided into 2 subdivisions:
• **Somatic Nervous Sysgtem (SNS) Skeletal Muscle
• **Autonomic Nervous System (ANS) Cardiac, Smooth, Glandular

The efferent division begins inside the CNS and ends at the Effector

• Sympathetic - Fight Fight Fight
• *Activated during exercise, excitement, and emergencies

• Parasympathetic rest and digest
• *Concerned with conserving energy

Neurons: responsible for the transfer and the processing of information in the nervous system

Neueoglia: Support Cells

• Neuroglia have many functions including:
• *providing the framework for the neural tissue
• *maintaining the intercellular environment of the neuron
• *Act as phagocytes (protection)

• 100 billion neuroglia or glial cells
• *roughly 5 tines the number of neurons

• Types
• *CNS
• **Astrocytes
• Microglia
• Ependeymal Cells
• Oligodendrocytes

• PNS
• *Satellite Cells
• *Schwan Cells

Are the largest and the most numerous glial cells.

• Have a variety of functions:
• Maintaining the blood brain barrier
• Creating a three dimensional framework for the CNS
• Performing repairs in damaged neural tissue
• Guiding neuron development
• Controlling the intersitial enviorinment

Produce the CSF

• Produce a myelin sheath in the axons (insulating sheath)
• Creates a faster impulse conduction along the axon

Nodes of Ravier is the jumping action called saltatory from node to node

Satellite Cells - are found in assoc. of the cell body of the neurons

Regulates nutrients for the body

Counterpart to the oligodendrocytes

Peripherial Cells

White Matter = myelinated axons (lighter in appearance)

Grey Matter = non myelinated axons, cell bodies, and dendrites (Darker in Appearance)

the cellbody is more in the center of the extension away from the tree portion.

Brings in Sensory information

3 types

• *Sensory Neuron
• **Send Nerve impulses from a sense organ (receptor) to the CNS

• *Interneuron
• **Contained within the CNS
• **Receives Impulses form the Sensory Neurons and/or Interneurons

• *Motor Neuron
• **Sends nerve impulses away from the CNS to an Effector

Bundles of Axons in the PNS = Nerves

Bundles of Axons in the CNS = Tracts

Collection of the cell bodies in PNS = Ganglia

Na+ ion movement across a membrane

polarity change of membrane surface (transmembrane potential)

Travels along the membrane surface like a "Domino Effect"

Current passes through a myelinated axon only at the nodes of Ranvier

Voltage gated Na+ channels are concentrated at these nodes

Action potentials are triggered only at the nodes and jump from one node to the next

much faster than conduction along unmyelinated axons