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 depolarization 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)

cerebrum, lateral ventricles, diencephalon, retina, third ventricle

mesencephalon (midbrain)

midbrain and cerebral aqueduct

rhombencephalon (hindbrain)

pons, cerebellum, 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

reflex arc

receptor, sensory neuron, integration center, motor neuron, effector

mechanoreceptors

touch, pressure, pain, proprioception, vibrations

thermoreceptors

temperature

chemoreceptors

chemicals

photoreceptors

light

nociceptors

pain/inflammation

exteroreceptors

at/near body surface

interoreceptors

inside body

sympathetic nervous system

fight or flight; dilate pupil, reduce saliva, peripheral blood vessels constrict, vasodilate bronchioles, increase heart rate, slow stomach secretions and peristalsis, no insulin produced, increased production of epinephrine and norepinephrine, decrease urine production, ejaculation, relax uterus

parasympathetic nervous system

rest and digest; pupil constricts/focuses, increase lacrimal gland functions, increase saliva, lower heart rate, bronchioles constrict, produce insulin, increase digestion, increase urine production, arousal, contract uterus

cholinergic receptors

use Ach; nicotinic, postganglionic neurons, adrenal medullary cells; muscarinic, parasympathetic target organs

adrenergic receptors

use norepinephrine and epinephrine; heart, sympathetic target organs, adipose tissue

types of papilla on tongue

fungiform, foliate, circumvalate papillae have taste buds; filiform papillae have pain and touch receptors

gustatory path to brain

microvilli, taste pore, gustatory receptor cell, sensory neuron, solitary nucleus, thalamus, gustatory complex

parts of ear involved in hearing

external auditory meatus, tympanic membrane, malleus, incus, stapes, oval window, cochlea

parts of ear involved in balance

utricle, saccule, semicircular canals

hearing path to brain

sound goes through ear parts, vestibulocochlear nerve, thalamus and/or inferior colliculi, primary auditory complex

olfactory path to brain

cilia, dendrites, axon, glomerulus and mitral and tufted cells in olfactory bulb, thalamus, hippocampus and amygdala, temporal lobe

vision path to brain

cornea, anterior chamber, iris, pupil, lens, vitreous chamber, retina, optic nerve, thalamus and/or superior colliculi, primary visual cortex