NERVOUS

SYSTEM

1. Nervous System Notesheet2. Neuron Vocabulary3. Nervous System Web Lab Day 1 and 24. Neurons Notes (includes spinal nerve notesheet)5. Nervous System Crossword6. Quiz 17. Central Nervous System8. Blood-BrainBarrier Article & Summary

TOPIC #5

1. Cell body2. Nissl substance3. Neurofibrils4. Dendrites5. Axons6. Axonal terminals7. Neurotransmitters8. Synaptic cleft9. Synapse10. Myelin11. Schwann cells12. Myelin Sheath13. Neurilemma14. Nodes of Ranvier15. Nuclei16. Ganglia17. Tracts

Neuron Vocabulary

NEURONS

• Continuous conduction–Unmyelinated neurons

• Saltatory conduction–Myelinated neurons– Impulse travels faster as it jumps

from/to each Node of Ranvier• Video• Neurotransmitters carry impulses across

the synapse from pre-synaptic neurons to post-synaptic neurons

Parts 2 and 3

NEURAL IMPULSE

• Resting Potential– Inside neuron is negative relative to outside– Extracellulary: More Na+ ions– Intracellularly: More K+ ions

• Action Potential when neurons start firing messages/impulses– A strong enough stimulus causes charge reversal!– Positive Na+ ions rushing into neuron and K+ out =

DEPOLARIZATION!– Repolarization occurs when K+ ions diffuse out of cell

after impulse passes restoring overall negativity intracellularly

– Neuron cannot conduct another impulse until repolarization is restored

Part 8

• There are 12 pairs of cranial nerves in the PNS that serve the head and the neck. – Only one pair (the vagus nerve) extends to the thoracic and

abdominal cavities. • There are 31 pairs of spinal nerves in the PNS. – Formed by ventral & dorsal roots of spinal cord.– Named by the region of cord from which they arise.

• What happens after a spinal nerve is formed?– It divides into dorsal & ventral rami – Dorsal rami serve skin and muscles of posterior trunk– Ventral rami form plexuses (complex nerve networks that serve

the limbs, motor and sensory)• T1 – T12 spinal nerves – ventral rami form intercostal nerves– Serve muscles between ribs & skin and also anterior/lateral trunk.

TYPES OF NEURONS

• Embryonic development–Starts out as simple neural tube along

length–Anterior end expands by 4th week =

brain–Posterior end becomes spinal cord–Central canal enlarges into four main

regions

Central Nervous System

• SPINAL CORD–17 inches long–Continuation of brain stem–2-way communication pathway

to/from the brain–Major reflex center–Protected by vertebrae and

meninges–31 pairs of spinal nerves arise

from it–Cauda equina (page 227)

• BRAIN–4 main parts (page 215)1. Cerebral Hemispheres

Divided into lobes each with its own function

2. Diencephalon (interbrain)•Thalamus

•Epithalamus•Pineal Body•Choroid Plexus

•Hypothalamus•Limbic System•Pituitary Gland•Mammillary Bodies

3. Brain Stem – size of thumb, 3 inches long Midbrain Pons Medulla Oblongata Reticular Formation

4. Cerebellum – provides precise timing of voluntary muscle activity, controls balance and equilibrium

Draw sagittal suture of brain and color and label the parts we have talked about today (page 219)

• Meninges – connective tissue membranes that cover/protect the brain–Dura Mater–Arachnoid Mater–Pia Mater

• Cerebrospinal Fluid – continuously circulates in the brain maintaining normal pressure–What?–Formed from?–How can you test it?

• Blood Brain Barrier (homework)

Protection of CNS

DISEASES OF THE CNS