Lecture - Nerve Tissue Flashcards
What is the synapse?
The area where one neuron’s synaptic bulb meets up with the target tissue (muscle cell, other neuron, etc.)
What is the microscopic gap between the pre-synaptic neuron and the target tissue?
Synaptic Gap
4 kinds of neural circuit
- Diverging
- Converging
- Reverberating
- Parallel after-discharge
One nerve fiber synapses with several post-synaptic cells, one motor neuron stimulates thousands of muscle fibers
Diverging circuit
What’s a converging circuit?
Several nerve fibers converge into one neuron, multiple neurons channeled to one area of brain
When do neurons stimulate each other in a linear sequence?
Reverberating circuit - some neurons send an axon collateral back to first neuron
What is the name for the brain and spinal cord?
Central nervous system
What is the peripheral nervous system?
All nerve tissues not in the brain and spinal cord
What is the PNS divided into?
- somatic nervous system (motor)
- autonomic nervous system: sympathetic and parasympathetic nervous systems
What are the 2 primary cell types in nervous tissue?
- Neuron - transmits nerve impulses
2. Glial cells - support cell (neuroglia)
Which 4 glial cells are in the CNS?
- Astrocytes
- Ependymal cells
- Oligodendrocytes
- Microglia
Which CNS glial cells constitute 90% of CNS tissue in some parts of the brain, are star shaped, support neurons, and form the Blood-Brain-Barrier (BBB)?
Astrocytes
What do the ependymal cells do in the CNS?
- cubodal epithelium w/no basement membrane
- line internal brain cavities
- create cerebrospinal fluid by filtering fluid out of teh choroid plexus
Which glial cells in the CNS form the myelin sheath?
Oligodendrocytes - like an octopus
Which glial cells in the CNS act as the immune system?
Microglia - phagocytize (eat) dead matter or debris and respond to infections
What 2 glial cells are in the PNS?
- Schwann cells
2. Satellite cells
Which cells form the myelin sheath in the PNS?
Schwann cells (one per)
What is the function of satellite cells in the PNS?
Unknown; surround neuron cell bodies
What is the structure of a nerve from the inside out?
- Endoneurium: surround each neuron on the outside of the myelin sheath
- Perineurium: surrounds each fascicle (bundle of nerves)
- Epineurium: surrounds the nerve as a whole
Which part of the reflex arch transmits a pain signal from the receptor to the CNS?
Sersory (afferent) neuron
What is a sensory receptor?
It is a receptor that receives information from the environment, like pain
Which neuron inside the spinal cord connects the sensory neuron with the motor neuron and processes information to make decisions about how to respond to stimuli?
Interneuron
Which neuron makes up 90% of the body’s neurons?
Interneuron
What is a motor (efferent) neuron?
A neuron that carries information from the CNS to muscles and glands
In the reflex arch, what contracts in an adaptive response to the original stimulus?
Muscles or glands
What is the name of the cell body of a neuron which contains the nucleus, endoplasmic reticulum, mitochondria, ribosomes, ect. ?
Soma
What is a dendrite?
The part of a neuron that receives the nerve impulse from the pre-synaptic neuron or responds to mechanical, electrical, or thermal stimulation
What is the name for the enlarged portion of the nerve axon where the cell body connects with the axon?
Axon hillock
What transmits action potential to the synaptic bulb?
The axon
What is the synaptic knob/bulb?
Enlargement at the end of the axon which contains neurotransmitters
What is the cell membrane around the axon called?
Axolemma