Overview of Nervous System
What are the two major subdivisions of the nervous system and what do they include?
CNS - brain and spinal cord
PNS - nerves and ganglions
For which type of memory are the synapses physically remodeled?
long-term
What does the dorsal root ganglion contain?
sensory neurons - primarily the somas
Where is gray matter found in the brain (2 places)
forms cortex over the cerebrum and cerebellum and forms nuclei deep within the brain
term for the unconscious, automatic responses to stimulation of glands, cardiac or smooth muscle
visceral reflex
Give an example of a stimuli the visceral sensory division would respond to
internal organs
The brain knows what type of sensory information travels on each fiber - what is the term for this? Is it qualitative information or quantitative information?
labeled line code - qualitative
What does decussation mean?
the fibers cross sides
What is the function of the fourth ventricle
CSF escapes through here to surround the brain
What are the two divisions of the ANS and their function
sympathetic division: fight or flight (prepares body for physical activity - increases HR, BP, airflow, blood glucose levels, etc)
parasympathetic division: rest and digest (calms many body functions and assists in bodily maintenance - digestion and waste elimination)
What type of axonal transport is responsible for allowing viruses to get into neurons
fast retrograde
Explain the difference between temporal and spatial summation
temporal - a single synapse receives many EPSPs in a short time
spatial - a single synapse receives many EPSPs from many cells
Dura mater: tough collagenous membrane surrounded by epidural space
Arachnoid mater: layer of simple squamous epithelium lining dura mater and loose mesh of fibers filled with CSF
Pia mater: delicate membrane adherent to the spinal cord (like Saran Wrap)
What are the four "centers" of the medulla?
cardiac center (adjusts rate and force of heart), vasomotor center (adjusts blood vessel diameter), respiratory center (controls rate and depth of breathing, reflex center (for coughing, sneezing, gagging, swallowing, vomiting, salivation, sweating, movements of tongue and head)
What are the two types of dual innervation and an example of each
antagonistic: HR (parasympathetic decreases, sympathetic increases), pupil (parasympathetic constricts, sympathetic dilates)
cooperative: saliva (parasympathetic increases salivary serous cell secretion, sympathetic increases salivary mucous cell secretion)
Name the SIX types of neuroglial cells and their basic function
Oligodendrocytes - myelinated CNS
Ependymal cells - line cavities, produce CSF
Microglia - immune function
Astrocytes - form framework of CNS, contribute to BBB and regulate composition of brain tissue fluid, convert glucose to lactate to feed neurons
Schwann cells - myelinate PNS
Satellite cells - uncertain function
Name the FOUR types of circuits and an example of each.
diverging - the brain
converging - retina
reverberating - remembering names
parallel after-discharge - after-imaging
Name the FOUR spinal tracts, a brief description, and if they are ascending or descending
spinothalamic: ascending; pain, pressure, temperature, light touch, tickle, and itch; decussation of second order neuron occurs in spinal cord
tectospinal: descending; reflex turning of head in response to sights and sounds
reticulospinal: descending; controls limb movements important to maintain posture and balance
vestibulospinal: descending; postural muscle activity in response to inner ear signals
Degeneration of the substantia nigra leads to tremors and Parkinson disease - explain why
The substantia nigra releases dopamine (normal function), which is a NT that has an effect on slowing down or ceasing muscle contraction. If the substantia nigra isn't working properly, not enough dopamine is being released which leads to tremors and Parkinson disease because without sufficient dopamine muscle contractions cannot be slowed down. Deep brain stimulation electrically stimulates the substantia nigra to release dopamine which works temporarily
Explain what the sympathetic tone of blood vessels is
sympathetic division innervates blood vessels (no dual innervation) - constricts or dilates the blood vessels depending on frequency. increase in firing frequency constricts blood vessels and decrease in firing frequency dilates blood vessels.
Explain why saltatory conduction is faster than impulse conduction (unmyelinated)
For myelinated axons (saltatory conduction), there is a high concentration of sodium channels in the Nodes of Ranvier and the channels open and close at the same time so huge amounts of sodium rushes in then huge amounts of potassium rush out creating a huge spark, allowing the action potential to "jump" to the next Node of Ranvier. Impulse conduction of unmyelinated fibers is slower because there are many voltage gated channels on the axon so a series of action potentials is created, like a row of dominoes, creating a slow and steady response.
For each of the following state which NT is used, what channels/system the NT activates, and what the result of the this activation is - excitatory cholinergic, inhibitory GABA-ergic, and excitatory adrenergic
excitatory cholinergic: NT = ACh, triggers opening of sodium channels which produces a local potential (when reaches threshold, triggers AP)
inhibitory GABA-ergic: NT = GABA, triggers opening of Cl- channels which produces hyperpolarization
excitatory adrenergic: NT = NE, acts through a second messenger system which results in enzymatic amplification
List the pathway of a somatic reflex arc
stimulation of somatic receptors, afferent fibers carry signal to dorsal horn of spinal cord, one or more interneurons integrate the information, efferent fibers carry impulses to skeletal muscles, skeletal muscles respond
Explain the following concepts as they relate to memory - anterograde amnesia, retrograde amnesia, hippocampus, cerebellum, and amygdala
anterograde amnesia: no new memories
retrograde amnesia: can't remember old memories
hippocampus: conscious memory, organizes sensory and cognitive information into a new memory, formation of long-term memory
cerebellum: helps learn motor skills
amygdala: unconscious memory, emotional memory (bypasses normal process of making long-term memory)
What are the two types of cholinergic receptors (ACh) and explain where they are. What are the two classes of adrenergic receptors (NE) and are the usually excitatory or inhibitory?
cholinergic receptors: nicotinic receptors on all ANS postganglionic neurons, in adrenal medulla, and at NMJs, excitatory when ACh binds; muscarinic receptors on all glands, smooth muscle and cardiac muscle cells that receive cholinergic innervation, excitatory or inhibitory, binds ACh or NE
adrenergic receptors: alpha is often excitatory and beta is often inhibitory