Intro to Nervous System Flashcards
Describe the components of a chemical synapse
The presynaptic ending that contains neurotransmitters. The synaptic cleft between the two nerve cells. The postsynaptic ending that contains receptor sites.
What does axodendritic mean? Axosomatic?
- Axodendritic: axon to dendrite, Most common
- Axosomatic: axon to cell body
What is an electric synapse
gap junctions between neurons
What is tic doulouroux?
Extremely painful chronic condition , A blood vessel compresses the trigeminal nerve causing loss of myelination of sensory nerve fibers, The lack of insulation allows touch and pain nerve fibers to cross-talk, Touch is perceived pain by brain
How does regeneration occur in the PNS? Does it occur in the CNS? Explain.
- In the PNS: If only axon is destroyed (not cell body), Schwann cells help axon sprout through a regeneration tube, There can be partial recovery
- In the CNS: historically no, but possibly in hippocampus and olfactory bulb
Using your own example, indicate the general flow of stimulation through the nervous system
- SENSORY INPUT: fly lands on arm and bends one or more hairs activating neurons wrapped around hair root
- INTEGRATION: activation of neurons processed by brain and/or spinal cord
- MOTOR RESPONSE: muscles of your other arm are activated so you can reach over and brush off fly
Compare the CNS and PNS
- CNS: Integration and interpretation of sensory input, Dictates motor response, Brain and spinal cord
- PNS: Neurons transport sensory input toward CNS & motor output away from CNS, Includes cranial and spinal nerves
Visceral and somatic nervous systems are involved with which parts of the body?
Visceral functions: organs within body cavities
Somatic functions: all other structures, esp. muscles and skin
Compare neurons and neuroglia
- Neurons: Able to respond to a stimulus and carry and electrical impulse, Excitable cells
- Neuroglia: Help neurons function more efficiently, Non-excitable cells
Functions of Astrocytes
- Most abundant glial cell
- Surround capillaries and neurons
- Forms the blood brain barrier
- Regulate neurotransmitter levels
- Increase blood flow to active brain regions
- Produce BDNF (brain-derived trophic factor) which promotes neural growth
Functions of Microglia
- Smallest and least abundant glial cell in CNS
- Macrophages
- Consume microorganisms and dead neurons
- Originate in red bone marrow and migrate to CNS during fetal development
Functions of Ependymal Cells
- Form simple epithelium that lines hollow portions of brain and spinal cord
- Have cilia that help circulate cerebrospinal fluid in CNS
Functions of Oligodendrocytes
- form Myelin sheaths in the CNS
- have many processes that wrap around many different axons
Functions of Satellite Cells
- In PNS
- Surround cell bodies
- Prevent “crossover” when many cell bodies are crowded together
Functions of Schwann Cells
Surround axon, form myelin sheaths in PNS
