Nervous System Part 3 Flashcards
Long-term potentiation (LTP)
- Strengthens synapse
- Learning
- Memory
Endogenous opioids
- Pain regulation
– agonists: morphine, codeine - Eating/drinking
- Circulation
- Mood & emotion
Nitric oxide
- Erection
- Learning
- Development
- Sensory & motor modulation
ATP & adenosine
- Pre- and post-synaptic receptors
- Ongoing research to determine functions
Somatic Nervous System
Efferent pathway
– Cell body in CNS
– Thick, myelinated, group A fiber
– Extends in spinal or cranial nerve to skeletal muscle
Neurotransmitter effect
– NT is acetylcholine (ACh)
– Effect always stimulatory
Autonomic Nervous System
Efferent pathway: Uses 2 neurons chain
1. Preganglionic neuron
– Cell body in CNS
– Thin, lightly myelinated preganglionic axon
2. Postganglionic neuron
– Cell body in autonomic ganglion outside CNS
– Nonmyelinated postganglionic axon that extends to effector organ
Neurotransmitter effect
– Preganglionic fibers release ACh
– Postganglionic fibers release Ach or norepinephrine at effectors
– Effect is either stimulatory or inhibitory, depending on type of receptors
Location of ganglia
Sympathetic: Close to the spinal
cord
Parasympathetic: Within or very close
to the organ
Role of the Parasympathetic Division
- Promotes maintenance
activities and conserves body
energy - Imagine a person relaxing and
reading after a meal
– Blood pressure, heart rate, and
respiratory rates are low
– Gastrointestinal tract activity high
– Pupils constricted; lenses
accommodated for close vision
Role of the Sympathetic Division
Mobilizes body during activity
– Controls:
* Exercise
* Excitement
* Emergency
* Embarrassment
- During a stressful situation:
– Increased heart rate
– Dry mouth
– Cold, sweaty skin
– Dilated pupils
Sympathetic vs parasympathetic
Sympathetic division
* Increases heart and respiratory rates
* Inhibits digestion and elimination
Parasympathetic division
* Decreases heart and respiratory rates
* Allows for digestion and discarding of wastes
