Lecture 8 - Nervous System #1 Flashcards
What are the two major divisions of the Nervous system?
- > Central nervous system (brain and spinal cord) - > peripheral nervous system (anything else, adjacent nerves etc.)
What are the main properties of the nervous system
Excitable - > respond to stimuli
Conductivity - > excited cells conduct and transport impulse
Secretion - > neurotransmitters are secreted in reaction to impulses
Longevity - > most neurons will last a lifetime
Amitotic - > (amitotic cells cannot replicate through mitosis) *LAST TWO ARE CONNECTED*
types of nervous tissue
Neurons - > larger, responsible for impulse propigation
Neuroglia - > smaller, support/ maintain neuron cells
Label the neuron
astrocytes
- > in CNS
- > form blood-brain barriers by covering caplaries with perivascualr feet
- > small molecules can go through the gaps and into the bloodstream (water or glucose)
oligodendrocytes
- > reponsible for making myelin (allows faster impulse propgation)
- > attached to myelin sheath of neuron
- > in CNS
Microglia
- > in CNS
- > small cells near blood vessels which clear away waste/ dead cells (phagocytic cells)
Ependymal cells
- > in CNS
- > form epithlial membrae that lines brain and spinal cavities
- > produce cerebrospinal fluid
Satelite cell
- > in PNS
- > small flat cells which surround the neronal soma (cell body of unipolar neurons)
pns ganglia
ganglia (pl. ganglion) are a group of neuron cell bodies located in the peripheral nervous system which house the cell bodies of afferent and efferent nerves
schwaan cells
- > in PNS
- > cells encicling PNS axons with myelin sheaths
- > gaps in between are called nodes of ranvier
- > increase propogation speed
Myelinated vs Unmyelated axons
Myelinated
- > fully covered
- > white tissue
Unmyelinated
- > embeded in the surface; not wrapped
- > grey matter
- > adding chocolate chips to cookies
What are synapses
- > where a neuron connects to either another neuron or muscle
- > use chemical neurotransmitters to induce an electrical charge
What are the parts of the synapses
- Presynaptic bulb
- > synaptic vescicles
- > Synaptic end bulb
- > presynaptic membrane - Postsynaptic neuron
- > Postsynaptic membrane
(neurotransmitter receptor site)
- Synaptic crest
Classification of Neurons
- > Multipolar neurons (most neurons)
- > Bipolar neurons (cell body intergrated in middle of axon)
- > unipolar neuron (attaches to middle of the axon)
Basic functions of nervous tissue
Sensory (input) - > senses changes with sensory receptors
Integration - > interpreting and remembering those changes
Motor (output) - > reacting to those changes with EFFECTORS
What are effectors?
a gland or a muscle that becomes active in response to stimuli
(muscular contractions or glandular secretion)
Classification of Nerves
Mixed nerves - > both sensory and motor fibres; send impulses to and from CNS
Sensory (afferent) nerves - > send impulses towards CNS
Motor (efferent) nerves - > send impulses away from CNS
Sensory Neurons
- > neurons of the sensory nervous system
- > conduct impulses from somatic and visceral receptors
- > most unipolar, cell bodies found in poserior root ganglia
Interneurons
- > receives, processes and stores information from stimuli from many different neurons
- > “decides” how body responds to stimuli
- > generally multipolar
Motor neurons
- > conduct motor output to somantic and viceral effectors
- > all multipolar
parts of a nerve cell
- > Endoneurium (wraps axon)
- > perineurim (wraps fasicles/multiple axons)
- > epineurium (wraps nerve)
What is the fasicle
A bundle of axons wrapped in perineurium
which two systems further divide the peripheral nervous system and what are their functions
Sensory (afferent) division
- > conduct impulses to the CNS
Motor (efferent) division
- > conduct impulses away from the CNS to effectors (muscles or glands)
