Intro To The Nervous System Flashcards
3 subdivisions of the PNS
Somatic nervous system–> skeletal m
Autonomic nervous system–> smooth muscle, cardiac m, glands
Enteric nervous system–> smooth m, glands, endocrine cells of GI tract
What are ganglia. What nervous system are they part of
Ganglia - cluster of nerve CELL Bodies in PNS
The – canNOT undergo cellular division
Neuron
The cell body of the neuron contain – –, rough ER that synthesize proteins for growth and regeneration of damaged axons in PNS
Nissl bodies
Flow of impulses from dendrites
Dendrite–> body –> axon –> terminals
Anterograde transport = directed forward in time
Products move from body to axon terminals
Develop/regenerate axons
Replenish axoplasm
Structural classification of neurons is based on what? List the types
Based on number of processes/dendrites
Multipolar
Bipolar
Unipolar
Which structural type of neuron transmits info fastest and why?
Unipolar neuron
Impulse bypasses cell body
Functional classification of neurons is based on what? List the types
Functional - direction in which impulse is conveyed
Sensory = afferent = towards CNS
Motor = efferent = away from CNS
Interneuron = bw sensory and motor neurons
The neurons of the CNS are – bc there are several dendrites and one axon
Multipolar
Purpose of neuroglia
Support, nourish, protect, maintain homeostasis
Do NOT conduct impulses
4 types of neuroglia in CNS
Astrocytes
Oligodendrocytes
Microglia
Ependymal cells
2 types of neuroglia in the PNS
Schwann cells
Satellite cells
In the blood brain barrier (CNS), – inhibit harmful substances in blood from moving into neurons
Astrocytes
– are CNS neuroglia that form and maintain myelin sheaths
Oligodendroctyes
– in CNS phagocytose microbes & damaged nervous tissue
Microglia
– in CNS form the blood-CSF barrier
Ependymal cells (think epidermis = barrier)
PNS neuroglia that forms myelin sheath around axons
Schwann cells
When does the process of myelination (PNS) begin?
In utero
Outer layer of myelin sheath (PNS)
Schwann cell cytoplasm and nucleus
Outermost nucleated cytoplasmic layer of Schwann cells; aide in regeneration
Neurolemma
– in CNS myelinates parts of axons
Oligodendrocytes
CNS or PNS easier to regenerate and why?
Little regeneration for CNS neurons bc oligodendrocytes lack NEUROLemma
– matter contains cell bodies, dendrites, UNmyelinated axons, axon terminals, neuroglia
– matter contains myelinated axons
Gray - UNmyelinated
White - myelinated
Distribution of matter in brain
Inner white bc myelinated axons transmit signals from one region of brain to another
Thin outer covering of gray
Graded potential vs action potential
Graded - short distance
Action - long distance (ie impulse)
For a motor response, a – potential is formed in dendrites -> – potential travels down axon -> neurotransmitter release
Graded potential in dendrites
Action potential in axon
What production of potentials depends on (plasma membrane)
- Resting membrane potential
2. Ion channels/flow of ions
