Neurology

Lecture 1 Part 1

The Final Frontier

• Space the final frontier?

• The brain, the final frontier!

The nervous system consists of:

• The Brain• Spinal Cord• Peripheral Nerves• Divided system

– Central Nervous System (CNS)• Brain & Spinal Cord

– Peripheral Nervous System (PNS)• Nerves (peripheral &

Cranial)

Nervous System

• Controls and coordinates all parts of the body

• By transmission of electrical impulses (Electrical-chemical system)

Purpose of the Nervous System

• Control Center• Communication

Receive evaluate respond

• Stimulation of Movement

• Maintains Homeostasis– Along with the what

system?• Endocrine

Function of Nervous System

• Coordination & Control1. Receive info (stimuli)2. Computes info

determines responses3. Transmit info action

Neuron

• Basic functional unit– Afferent neuron

• Sensory• Carry info from PNS

CNS– Efferent neuron

• Motor• Carry into from CNS

PNS

Neuron structure

• Cell body/ Soma– Nucleus

• Dendrites– Carry impulses toward

the cell body

• Axons– Carry impulses away

from the cell body

Damaged Neuron

• CNS = – Irreversible

• PNS = – will repair itself if the

cell body is not destroyed

Synaptic Junction

• Neuron connect to each other end to end

• Where two neurons come together– Synaptic junction– Synapse– Inter-neuron space

Synaptic Junction

• Terminal end of Axon = Synaptic Vesicles

• Nerve impulse reaches the vesicle release substance neurotransmitters into the synaptic junction

• Nerve impulses must have a receptor site

Neurotransmitters

• Synthesized in the soma

• Special Properties– Excitability – Inhibitory– Modify

• 30+ neurotransmitters

Excitatory Neurotransmitters

• Serotonin– Sleep– Sensory perception– Temperature– Mood– Inhibits pain

Excitatory Neurotransmitters

• Dopamine– Gross subconscious

movement– Fine motor skills– Emotional responses

Excitatory Neurotransmitters

• Norepinepherine– Maintains arousal – Overall activity– Mood

• Acetylcholine– Vital for short term

memory– Speeds impulse

transmission

Inhibitory Neurotransmitters

• Cholinergics– Stabilizers– Inhibitors

• GABA• Dopamine

– Basal Ganglia– Acetylcholine &

Dopamine are opposites which work together to create homeostasis

Neuropeptides

• Not neurotransmitters• Encephalin• Chemical endorphins

– Suppress pain– Memory– Learning– Sexual activity

Nerve Impulse

• The nervous system is powered by electrical and chemical energy– K+– Na+– Cl-– (Ca+)

Nerve Impulse

• Absolute retraction period– The time interval

phase that occurs when the neuron cannot be re-stimulated