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