Nervous Tissue Flashcards
What are the two main divisions of the nervous system?
Central Nervous System (CNS) and Peripheral Nervous System (PNS).
What does the sensory (afferent) division do?
Carries information to the CNS.
What does the motor (efferent) division do?
Carries information from the CNS to tissues.
What are the functions of the nervous system?
Behavior, perception, memory, voluntary movement, homeostasis.
What are the three processes of nervous system function?
Sensory (detects stimuli), Integration (processes info), Motor (stimulates glands/muscles).
What are the components of the CNS?
Brain and spinal cord (and optic nerve).
What are the functions of the brain?
Control center for voluntary/involuntary activities, integrates complex activities.
What are the functions of the spinal cord?
Relays information to/from the brain, integrates less complex activities.
What are special senses?
Taste, hearing, sight, smell, balance (equilibrium).
What are neurons?
Nerve cells that transmit electrical signals.
What is the structure of a neuron?
Cell body (soma), dendrites (receive signals), axon (conducts signals).
What is the function of an axon?
Conducts action potentials to another neuron or tissue.
Can neurons divide?
No, neurons cannot divide.
What is the metabolic rate of neurons?
High; they die rapidly without oxygen.
What are the four types of neurons?
Multipolar, unipolar, bipolar, anaxonic neurons.
What are multipolar neurons?
Most common type, multiple dendrites, one axon, found in CNS and motor neurons.
What are unipolar neurons?
Dendrites and axons are continuous, soma off to the side, most sensory neurons.
What are bipolar neurons?
One dendrite, one axon, found in special sense organs (sight, smell, hearing).
What are anaxonic neurons?
Found in special sense organs and brain, no clear distinction between axon and dendrites.
What are neuroglia?
Supporting cells of the nervous system, more numerous than neurons.
What are the functions of neuroglia?
Support, repair, phagocytosis, nutrient supply, regulate interstitial fluid.
What are astrocytes?
Most common CNS neuroglia, form syncytium, maintain blood-brain barrier, provide structural support and repair.
How do astrocytes maintain the blood-brain barrier?
They wrap around capillaries and influence permeability.
What are microglia?
Resident macrophages in CNS, phagocytose foreign particles.
What are ependymal cells?
Line brain ventricles and spinal cord, produce cerebrospinal fluid (CSF), have cilia & microvilli.
What are oligodendrocytes?
Form myelin sheaths around CNS axons, can myelinate multiple axons.
What is the function of myelin?
Increases speed of action potential conduction.
What are the PNS neuroglia?
Satellite cells and Schwann cells.
What is the function of satellite cells?
Support and regulate fluid exchange around PNS neurons.
What is the function of Schwann cells?
Form myelin sheath around PNS axons (one axon per Schwann cell).
