Nervous Tissue Flashcards
What system is nervous tissue an essential component of?
Nervous system
What subgroups comprises the nervous system?
Central Nervous System (CNS) and Peripheral Nervous System (PNS)
What are some functions of nervous tissue?
Maintains homeostasis (along with endocrine system)
Initiates voluntary movements
Perception
Behaviour
Memory
List 3 types of neural activity
Sensory - detection of internal/external stimuli and transfer to CNS
Integrative - analysis and storing of information
Motor - stimulation of effectors (e.g muscles and glands) through PNS
List the two neural cell types
Neurons (nerve cells)
Neuroglia (supportive cells)
What is the structure of a neuron?
Cell body
Short branched dendrites - convey nerve impulses
Axon - conducts nerve impulses to another neuron or tissue
List the 3 structural classifications of neurons
- Multipolar
- Bipolar
- Unipolar
List the structural features of a multipolar neuron and give an example of a multipolar neuron.
Several dendrites
One axon
All motor neurons (muscles) are multipolar neurons
Describe the structure of a bipolar neuron and give an example of where a bipolar neuron may be found
One dendritic process (unbranded at cell body)
One axon
Cell body found between dendrite and axon
Special sense organs - sight, smell, hearing
Describe the structure of a unipolar neuron and give an example of a unipolar neuron
Dendrites and axon continuous
Cell body off to the side
Most sensory nerves are unipolar neurons
List the 3 functional classifications of neurons and the structural classification they’re associated with
Sensory (afferent) - unipolar
Motor (efferent) - multipolar
Interneurons - multipolar
What are neuroglia?
Neural cells found in both the CNS and the PNS. Do not propagate action potentials/nerve impulses.
List the 4 types of CNS neuroglia
- Astrocytes
- Oligodendrocytes
- Microglia
- Eppendymal cells
What is the structure and function of an astrocyte?
Star shaped
Support
Contributes to blood brain barrier
What is the function of an oligodendrocyte?
Forms myelin sheath around CNS axons via secretion. Can form multiple myelin sheaths from one cell.
What is the function of microglia in the CNS?
Phagocytise, active immune defense in CNS
What is the function of eppendymal cells in the CNS?
Production of cerebrospinal fluid
What two types of neuroglia can be found in the PNS?
- Schwann cells
2. Satellite cells
What is the function of a Schwann cell in the PNS?
Wraps around axons to form myelin sheath. One cell per axon.
What is the function of a satellite cell in the PNS?
Surrounds cell bodies
Support
Fluid exchange
What are the similarities and differences between oligodendrocytes and Schwann cells?
Oligodendrocytes: found only in CNS, secretes myelin sheath around axons, capable of secreting sheaths for multiple axons
Schwann cells: found only in PNS, forms myelin sheath around axons by wrapping around it, one cell per axon
Define dendrite
A short branched extension of a nerve cell
Define axon
Long thread-like part of a nerve cell; impulses from cell body to other cells.