A&P nervous system assessment 4

parts of a neuron

nucleolus, nucleus, cell body, dendrites, axon, nodes of Ranvier, myelin sheath, axon terminal

structural classifications of neurons

multipolar, one axon, many dendrites; bipolar, one axon, one dendrite; unipolar, only axon, no dendrites

functional classifications of neurons

sensory/afferent, signals from skin and visceral organs; interneuron/association, carry messages between neurons; motor/efferent, signals to muscles and glands

what speeds up a nerve impulse?

more myelin, thicker diameter of axon

neuroglial cells and functions in CNS

astrocytes, support and anchor neurons to capillaries, control environment around neurons; ependymal cells, line central cavity of CNS, form barrier between CSF and brain; oligodendrocytes, make myelin sheath; microglial cells, perform phagocytosis, monitor health

neuroglial cells and functions in PNS

satellite cells, control environment around neurons; Schwann cells, make myelin sheath

3 types of nerve fibers

group A, somatic/motor, skin, skeletal muscle, joints, myelinated, 150 m/s; group B, ANS, lightly myelinated, 15 m/s; group C, sensory, skin, visceral, unmyelinated, 1 m/s

events of neuron synapse

action potential arrives at axon terminal, calcium channels open, synaptic vesicles release neurotransmitters, neurotransmitters diffuse across synaptic cleft and binds to receptors, opens ion channels, causes graded potential, neurotransmitters destroyed from synaptic cleft

what is an IPSP?

inhibitory postsynaptic potential; causes hyperpolarization of postsynaptic membrane

what is an EPSP?

excitatory postsynaptic potential; causes depolariztion of postsynaptic membrane

sequence of action potential

resting potential, reaches threshold, depolarization, repolarization, hyperpolarization, resting potential

no summation

type of graded potential; multiple EPSPs separated by time; no action potential

temporal summation

type of graded potential; multiple EPSPs in rapid sequence; action potential

spatial summation

type of graded potential; multiple EPSPs from different locations at same time; action potential

spatial summation of EPSPs & IPSPs

type of graded potential; both occur at same time and cancel each other out; no action potential

what are neurotransmitters?

neurotransmitters create graded potentials

serotonin

neurotransmitter; mood regulation, hunger, sleep, anger control, sexual desire; too little causes depression, OCD, chronic fatigue

dopamine

neurotransmitter; motor movement, alertness, good feelings, aggression, thinking, planning; too much causes Parkinson’s; too little causes schizophrenia, lack of remorse and affection

endorphins

neurotransmitter; pain control, stress reduction, pleasure; too little causes low pain tolerance, depression, sleep issues

acetylcholine (Ach)

neurotransmitter; motor movement, learning and memory, deep sleep; too little causes Alzheimer’s, dementia, muscle disorders

GABA (gamma-aminobutyric acid)

inhibitory neurotransmitter; reduces anxiety and insomnia, inhibits CNS/muscle tone; too little causes seizures, epilepsy, insomnia, anxiety, depression, mood disorders

norepinephrine

neurotransmitter; fight or flight response, alertness, increased heart rate; too much causes depression, racing heart, manic; too little causes lack of drive, less focus on goals

adenosine

inhibitory neurotransmitter; promotes sleep by suppressing alertness; too little causes restless leg syndrome

glutamate

neurotransmitter; major excitatory actions in brain, learning, memory; too much causes Alzheimer’s; too little causes seizures

how can drugs affect the neuromuscular junction?

drugs can either block or enhance events at the neuromuscular junction

prosencephalon (forebrain)

telencephalon, cerebrum and lateral ventricles; diencephalon, retina and third ventricleme

mesencephalon (midbrain)

brain stem and cerebral aqueduct

rhombencephalon (hindbrain)

metencephalon, pons and cerebellum; myelencephalon, medulla oblongata; fourth ventricle

sulcus (pl. sulci)

shallow dip

gyrus (pl. gyri)

elevated ridge

fissure

deep groove

function of cerebrospinal fluid (CSF)

cushions and reduces weight of brain

locations of CSF

ventricles and subarachnoid space

what is the blood brain barrier?

tight junctions between capillary endothelial cells keep brain homeostasis

what can pass through the blood brain barrier?

lipid-soluble molecules