Neurophysiology Flashcards
What kind of sensation do root hair plexi detect best?
initial contact and subsequent movement of regions of the body that have hair.
CSF occupies the space between the ____ mater (the middle layer of the brain cover, meninges) and the ____ mater (the layer of the meninges closest to the brain).
arachnoid; Pia
Where are b2-adrenergic receptors located, and what type of response do they mediate?
smooth muscle in vessels of heart and skeletal muscle, intestinal muscle, lungs and bronchi. Inhibition, relaxation.
How does the autonomic nervous system regulate the adrenal medulla? What receptor subtype is used?
the sympathetic division uses nicotinc receptors to cause the adrenal medulla secrete epinephrine and norepinephrine.
How many taste receptors (aka gustatory cells) are in a typical taste bud?
about 40
Proprioceptive information reaches our conscious awareness via the ___ pathway. Proprioceptive information that is outside of our awareness is delivered to the cerebellum via the ___ pathway.
posterior column; spinocerebellar
Where are a2-adrenergic receptors located, and what type of response do they mediate?
sympathetic neuroeffector junctions. Inhibition of effector cells.
T/F: Vitamin A provides opsin that becomes rhodopsin in the eyes.
false. vitamin A becomes retinal, a pigment that is combined with the opsin protein to become rhodopsin.
Name the sites of Pacinian corpuscles and their function.
deeper layers of the skin, ligaments, joint capsules, serous membranes and mesenteries involved in pressure, coarse touch, vibration and tension
Does significant peripheral adaptation occur to painful stimuli?
no
Which dermatome is important for early appendicitis pain referral to the umbilicus?
T10
How large is the hypothalamus, typically?
about the size of an almond
T/F: As a result of absorbing a photon, the photoreceptor membrane potential becomes more negative. (hyperpolarized)
true
Name the three types of mechanoreceptors.
tactile, baroreceptors, proprioceptors
What range of frequencies can the tympanic membrane resonate with?
20Hz to 20,000Hz
Traditionally which area the brain was thought to be responsible for speech comprehension?
wernicke’s area
Pressure waves distort the ___ on the way to the round window of the tympanic duct.
basilar membrane
Which components of the vestibular complex rely on the weight of the capula (a thick gelatinous fluid) to distort the hair cells?
semicircular ducts
List the cranial nerves that transmit purely motor information.
CN 3, CN 4, CN 5, CN 6, CN 7
Where is the L1 dermatome?
at the inguinal ligament
What type of reflex is described as sensory input from the muscle spindles and Golgi tendon organs to spinal the motor system?
spinal reflex
Cold receptors are three to four times ___ numerous than warm receptors.
more numerous
In general, only ___ -soluble compounds can diffuse into the interstitial fluid of the brain and spinal cord.
lipid
Which components of the vestibular complex, when coupled with visual input, accounts for our perception of acceleration/deceleration?
the saccule and the utricle
Which part of the PNS uses nicotinic ACh receptors? Which part tends to use muscarinic receptors?
when stimulated, the preganglionic nerve releases ACh ath the ganglion, which acts on nicotinic receptors of postganglionic neurons. The postganglionic nerve then releases ACh to stimulate the muscarinic receptors of the target organ.
What kind of sensation are Ruffini corpuscles most suited for?
continuous pressure and distortion (twisting, tugging) of the skin
What kind of sensation are Meissner’s corpuscles specially suited to detect?
fine touch and pressure (exact location, shape, size, texture). Also particularly good at detecting low-frequency vibrations.
How many taste buds does a filliform papilla contain?
none
Describe the parasympathetic function of CN 7.
parasympathetic input to the salivary and lacrimal glands.
Which part of the limbic system is involved in signaling the cortex regarding reward and fear in addition to social functions such as mating?
amygdala
T/F: The number of hair cells responding in a given region of the organ of Corti provides information about the volume of a sound.
true
Name three classes of nociceptor.
sensitive to temperature, sensitive to mechanical damage, sensitive to dissolved chemicals
Describe the frequency and location of beta brain waves. When do they normally occur?
12-30 Hz; both sides, symmetrical distribution, most evident frontally; normal when alert, active or concentrating.
List the sensory cranial nerves that also carry motor information.
CN 5, CN 7, CN 9, CN 10
Where do axons leaving the olfactory epithelium terminate?
the olfactory bulbs of the cerebrum
Name some important structures that are usually considered part of the limbic system. (7)
amygdala, hippocampus, parahippocampal gyrus, cingulate gyrus, fornix, hypothalamus, thalamus
What range of wavelength of light are our eyes sensitive to?
400-700nm
How many taste buds does a circumailate pailla typically contain?
about 100
Is the stretch reflex monosynaptic or polysnaptic? Cranial or spinal
spinal, monosynaptic reflex
Choroid plexus is present in all components of the ventricular system except for the ___ and the occipital and frontal horns of the lateral ventricles.
cerebral aqueduct
Which nerve root is responsible for the achilles reflex?
S1
T/F: The parasympathetic nervous system uses only acetylcholine (ACh) as its neurotransmitter.
true
Which adrenergic receptor subtypes increase or enhance lipolysis in adipocytes?
b1, b2, and b3
Describe the law of reciprocal innervation as it pertains to a reflex arc.
flexor and extensor reflexes of the same limb cannot contract simultaneously.
CSF returns to the vascular system by entering the dural ___ via the arachnoid ____.
venous sinuses; granulations/villi
In the dark, the cGMP gated sodium channels in photoreceptors are kept ____(open/closed), and the transmembrane potential is appropriately ____mV.
open; -40 mV
Which components of the vestibular complex provide information concerning movement of the head?
semicircular ducts
Movement of the ____ bone at the oval window establishes pressure waves in the perilymph of the vestibular duct.
stapes
How does the autonomic nervous system increase and decrease heart rate (chronotropic)? What receptor subtypes are used?
sympathetic division increases via b1. Parasympathetic decreases via M2.
Which dermatome is found at the level of the belly button?
T10
How does the autonomic nervous system regulate pupil size? Which receptor subtypes are used?
sympathetic division dilates via a1, causing mydriasis (this is contraction of the dilator muscle). Parasympathetic constricts via M3 causing miosis (relaxation of the dilator muscle).
How does the autonomic nervous system regulate beta and alpha cells of the pancreas? Which receptor subtypes are used?
the sympathetic division uses a 2 to decrease secretion from beta cells and increases secretion from alpha cells. The parasympathetic division uses M3 to increase secretion from alph cells and beta cells.
T/F: The circadian rhythm is actually 25 hours.
false
Where are nociceptors commonly found?
superficial portion of the skin, joint capsules, periostea of bones and around the walls of blood vessels
What are some important functions of the limbic system? (5)
feeding, fighting, feeling, flight and sex (The five Fs)
Which nerve root is responsible for the triceps reflex?
C7
T/F: There are four choroid plexus in the brain, one in each of the ventricles.
true
Where are a1-adrenergic receptors located, and what type of response do they mediate?
widespread, found in most tissue but not in heart. Excitation, stimulation of metabolism
Are receptor potentials graded or all-or-none phenomenon?
graded
Where do the sensory afferents of the taste buds converge?
the nucleus solitarius of the medulla oblongata
Describe the sensory component of CN VII.
receives the special sense of taste from the anterior 2/3 of the tongue.
Where are thermoreceptors found? (4)
dermis of the skin, skeletal muscle, liver, hypothalamus
Where is the C3 dermatome?
neck (high turtleneck shirt)
Stimulation of a nociceptor causes depolarization of a sensory neuron whose axon synapses on an interneuron, whose axon crosses the spinal cord to ascend within the ___ tract
lateral spinothalamic tract
What dermatome is found at the knee caps?
L4
Which part of the limbic system carries signals form the hippocampus to the mammilliary bodies and septal nuclei?
fornix
T/F: There is one kind of opsin in rods, and three types for the cones (one that detects red, one that detects blue, and one that detects green).
true
T/F: Temperature sensation is conducted along the same pathways that carry pain sensation.
true
Describe the primary function of the basal ganglia.
the basal ganglia mediates voluntary movements and postural adjustments
How does the autonomic nervous system increase and decrease cardiac contractility? What receptor subtypes are used?
sympathetic division increases via b1. Parasympathetic decreases via M2.
Slower type ____ fibers carry sensations of slow pain.
c
What kind of information are Merkel’s discs best suited to detect?
fine touch and pressure (exact location, size, texture, shape)
Where do axons leaving the olfactory bulb of the cerebrum terminate? (3)
olfactory cortex, hypothalamus, portions of the limbic system
Type ___ fibers trigger somatic reflexes and are also relayed to the primary sensory cortex, permit precise localization of the pain.
A
The cerebrospinal fluid is produced at a rate of __ml/day. Since the brain can only contain from ___ ml, it follows that the turnover rate it ___ per day.
500ml; 150ml/ 3-4 times
Stimulation of a nociceptor causes depolarization of a sensory neuron whose axon synapses on an interneuron, whose axon crosses the spinal cord to ascend within the ___ tract.
lateral spinothalamic tract
Function of the ventral posterior nucleus, lateral part (VPL)?
receives body senses (proprioception, pressure, pain, touch, vibration)
How does the autonomic nervous system regulate parietal cell activity? Which receptor subtypes are used?
the parasympathetic division increases gastric acid secretion, via M1.
Which components of the vestibular complex provide information concerning the position of the head with respect to gravity?
the saccule and the utricle
How does the autonomic system regulate platelet aggregation? What receptor subtype is used?
the sympathetic division can cause platelets to aggregate via a2 receptors.
Name the two types of ACh receptor
muscarinic and nicotinic
Which dermatome can be found at the level of the xiphoid process?
T7
T/F: Thermoreceptors are free nerve ending and there are no known structural differences between cold and warm thermoreceptors.
true
How does the autonomic nervous system regulate erection and ejaculation? Which receptor subtypes are used?
sympathetic division causes ejaculation via alpha receptors. Parasympathetic division causes errection via M3 receptors.
Which part of the limbic system plays a key role in the formation of spatial memory?
parahippocampal gyrus
The choroid plexus is a network of specialized _____ cells and ___ capillaries that manufactures CSF.
ependymal; permeable
Are receptor potentials depolarizations or hyperpolarizations?
they can be either.
How does the autonomic nervous system regulate salivary secretions? Which receptor subtypes are used?
sympathetic division stimulates viscous secretions via beat adrenergic receptors. Parasympathetic division secretes water secretions via M3 receptors.
Which dermatomes are associated with erection and sensation of penile and anal zones?
S2, S3, S4
S2,3,4 keeps the man begging for more
Where is the circadian ‘clock’ in mammals located?
in the suprachiasmatic nucleus (SCN), a pair of distinct groups of cells located the hypothalamus. Destruction of the SCN results in the complete absence of a regular sleep/wake rhythm. The SCN receives information about illumination through the eyes.
Describe the frequency of gamma brain waves. When do they normally occur?
30-100 Hz; normal in certain cognitive or motor functions that require higher neural integration.
Name some important functions regulated by the hypothalamus. (12)
gastric reflexes, maternal behavior, blood pressure, feeding, thirst, immune responses, temperature, heart rate, sweating, circadian, rhythms, memory, shivering and more
An adult has approximately ___ taste buds.
3000
Which enzyme and second messenger are activated when a molecule binds to an olfactory receptor?
adenylate cyclase, cAMP
Describe the frequency and location of delta brain waves. When do they normally occur?
up to 4 Hz; frontally in adults, posteriorly in children; normal in adult sleep and in awake babies
Tilting your head from side to side stimulates hair cells in the ____ semicircular duct.
posterior
Which adrenergic receptor subtype inhibits insulin release from the pancreas and induce glucagon release?
a2
Where are baroreceptors located? (4)
walls of blood vessels, portions of the digestive, reproductive and urinary tracts
Name three locations where the blood-brain barrier is not intact.
capillaries supplying portions of the hypothalamus (permits hypothalamic hormones to enter circulation and allows the hypothalamus to sample the blood); capillaries in the pineal gland (similar reasons); capillaries at the choroid plexus (regulation of CSF composition)
Is a spinal reflex response to a stimulus an involuntary or voluntary response?
involuntary (sneeze, eye blink, cremaster reflex)
Shaking your head ‘no’ stimulates hair cells of the ___ semicircular duct.
lateral
Which part of the limbic system is required for the formation of long-term memories and is implicated in maintenance of cognitive maps for navigation?
hippocampus
Which frequency is lost first in hearing loss in elderly?
high-frequency
Type ___ fibers cause a generalized activation of the reticular formation and the thalamus, providing only a general awareness of the location of the pain.
c
Name six cholinergic structures.
PNS (entirely); Neuromuscular junctions; preganglionic neurons of the SNS; Basal forebrain, brain stem complexes, sweat glands
T/F: There are no apparent structural differences between the free nerve endings that provide temperature, pain, and tactile information
true
What is the function of the medial geniculate nucleus?
auditory pathway (remember Medial is to hear Music)
Which nerve root is responsible for the biceps reflex?
C5
Cone shaped photoreceptors provide information about ___, and rods give information about _____
color, intensity
How does the autonomic nervous system regulate the musculature of the uterus? Which receptor subtypes are used?
sympathetic division relaxes via b2 (but also contracts in pregnancy via a1).
Which pair of hypothalamic hormones stimulate/ inhibits growth hormone secretion from the anterior pituitary?
growth hormone-releasing hormone/somatostatin
Name six hormones released by the hypothalamus.
CRH, DA, GnRH, GHRH, SS, TRH
which type of receptor is the most structurally and functionally complex of the general sensory receptors?
proprioceptors
Where is the C4 dermatome?
lower neck (low-collar shirt)
T/F: Pain receptors tend to be fee nerve endings with large receptive fields.
true
How does a photon-activated opsin molecule cause a change in the rate of neurotransmitter release form a photoreceptor? (4)
opsin activates transucin. Transducin activates phosphodiesterase. Phosphodiesterase breaks down cGMP. Lack of cGMP causes sodium channels to close. The transmembrane potential drops from –40mV towards -70mV
Name three cranial nerves that monitor taste buds.
CN 7, CN9 CN10
Which hypothalamic hormone stimulates the anterior pituitary to secrete LH and FSH?
gonadotropin-releasing hormone (GnRH)
How does the autonomic nervous system regulate sweat glands? Which receptor subtypes are used?
sympathetic division increases secretions via muscarinic receptors (major) and a1 (minor)
T/F: Sensory receptive fields may overlap but are always the same size.
false. they may overlap and have varying sizes form cm to fractions of a mm.
How does the autonomic nervous system regulate the sphincter of the bladder? Which receptor subtypes are used?
sympathetic division contracts via a1. parasympathetic division relaxes via M3.
Describe the frequency of theta brain waves. When do they normally occur??
4-Hz; normal in young children all of the times and normal in drowsiness or arousal in older children and adults.
Describe the sensory component of CN IX.
receives taste from the posterior 1/3 of the tongue.
List the purely sensory cranial nerves.
CN I, CN II and CN VIII
Are withdrawal reflexes monosynaptic or polysnaptic? Cranial or spinal?
polysnaptic, spinal
How does the autonomic nervous system generally increase and decrease vascular tone in arteries and veins? What receptor subtypes are used?
generally, the sympathetic division can constrict with alpha effectors but also dilate with beta 1 effectors. The parasymphatetic division dilates with M3 receptors
The choroid plexus epithelial layer is continuous with the ependymal cell layer that lines the ventricles, but unlike the ependyma the CP epithelial layer has ____ in between the cells on the side facing the ventricle.
tight junctions
Golgi tendon organs monitor tendon ____, and muscle spindles monitor muscle ____.
strain; length
Vibration of the affected region of the ____ membrane moves hair cells against the ___ membrane, leading to stimulation of acoustic sensory neurons.
basilar membrane; tectorial membrane
Which part of the limbic system autonomically regulates heart rate, blood pressure and cognitive and attentional processing?
cingulate gyrus
Where are b1-adrenergic receptors located, and what type of response do they mediate?
heart, kidneys, liver, adipocytes,. Stimulation, increased energy consumption
Do thermoreceptors adapt to temperature changes?
yes
Which part of the limbic system regulates the autonomic nervous system via hormone production and release. Also affects and regulates blood pressure, heart rate, hunger, thirst, sexual arousal and the sleep/wake cycle?
hypothalamus
Once the SCn of the hypothalamus has interpreted light information from the retinal, where does it send it?
to the pineal gland, which may respond by secreting melatonin.
Which adrenergic receptor subtype causes renin release from juxtaglomerular cells?
b1
How does the autonomic nervous system regulate the detrusor muscle of the bladder? Which receptor subtypes are used?
sympathetic divisions relaxes via b2. Parasympathetic contracts via M3.
Which components of the vestibular complex relies on the weight of otoliths to distort hair cells?
the saccule and utricle.
T/F: Olfactory reception occurs on the surface of the olfactory cilia.
true
Describe the histological basis of the blood brain barrier.
endothelial cells lining the capillaries of the CNS are extensively connected by tight junctions.
What is the Babinski reflex a sign of? When is it normal?
UMN lesion; it is normal during 1st year of life
How does the autonomic nervous system regulate GI smooth muscle motility? Which receptor subtypes are used?
the sympathetic division decreases with a1, a2, b1. The parasympathetic division increases with M1.
What part of the limbic system is the “relay station” to the cerebral cortex?
thalamus
Describe the crossed extensor reflex.
when a reflex is evoked on one side of the body, the contralateral side of the body will have an opposite response.
How does the autonomic nervous system increase and decrease cardiac output? What receptor subtypes are used?
sympathetic division increases via b1 receptors. Parasympathetic division decreases via M2 receptors.
Which parts of the hypothalamus produce oxytocin and vasopressin? (2)
paraventricular nucleus (PV and Supraoptic nucleus (SO) both produce these hormones. They are both roughly located anteriorly and medially in the hypothalamus.
How does the autonomic system regulate mast cells? What receptor subtype is used?
the sympathetic division can inhibit histamine release via b2 receptors.
Describe the sensory component of CN X.
conveys sensory information about the state of the body’s organs to the central nervous system.
How does the autonomic system regulate the smooth muscle of bronchioles? What receptor subtypes are used?
sympathetic division relaxes with b2 major and contracts with a1 (minor). Parasympathetic division contracts with M3.
Is a tendon reflex monosynaptic or polysnyaptic? Spinal or cranial?
polysynaptic and spinal
Describe the frequency of alpha brain waves. When do they normally occur?
8-12 Hz; posterior regions of head, both sides; normal when relaxed or reflective
Postural muscles usually have a __ muscle tone and extremely ___ stretch receptors.
firm; sensitive
Describe the parasympathetic function of CN III.
carries parasympathetic input to the ciliary ganglion to constrict pupil.
Which nerve root is responsible for the patella reflex?
L4
Name the four primary taste sensations.
sweet, salt, sour, bitter
Describe the parasympathetic functions of CNX.
parasympathetic input to the heart and lungs and gastro intestinal tract to the level of the splenic flexure of the colon.
Describe the sensory component of CN V.
receives sensation from the face, cornea, mouth, nose and temporomandibular joint
What is the function of the lateral geniculate nucleus?
visual pathway (remember Lateral is needed to Look)
Nodding your head ‘yes’ stimulates hair cells in the ___ semicircular duct.
anterior
List three functions of CSF
buoyancy, protection, chemical stability, prevention of brain ischemia
A ____ reflex regulates the length of a skeletal muscle. A ___ reflex prevents tearing or breaking caused by excessive contraction.
stretch; tendon
How many taste buds does a typical fungiform papilla contain?
about five
Traditionally which area of the brain was though to be responsible for speech production?
broca’s area
Which hypothalamic hormone inhibits secretion of prolactin from the anterior pituitary?
dopamine (DA)
Myellinated type ____ fibers carry sensations of fast pain.
a
Are we consciously aware of information sent by chemoreceptors?
no
Which adrenergic receptor subtype increases cardiac output, both by raising heart rate and increasing the volume expelled with each beat (increased ejection fraction)
b1
How does the autonomic nervous system regulate glucose production in the liver? Which receptor subtypes are used?
the sympathetic division increases glycogenolysis and gluconeogenesis via a1 and b2
T/F: The malleus, the incus and the stapes all vibrate when the tympanic membrane vibrates.
true
How does the autonomic nervous system regulate renin secretion in the kidney? Which receptor subtype is used?
the sympathetic division increases secretion via b1
___ frequency sounds vibrate the basilar membrane near the oval window and ___ frequency sounds vibrate basilar membrane further away from the oval window.
high frequency (=short wavelength); low frequency (=long wavelength)
Which hypthalamic hormone, with vasopressin, stimulates anterior pituitary to secrete ACTH?
coricotropin- releasing hormone (CRH)
Name the molecule that bids to presynaptic membranes in the limbic system, hypothalamus and reticular formation, preventing the release of the neurotransmitter called substance P.
endorphins. this is the mechanism whereby the conscious perception of pain can be reduced, even though the painful stimulus remains.
Name four stimuli the can alter the membrane potential of a free nerve ending.
chemical, pressure, temperature, trauma
Name the channel that is opened by cAMP when a molecule triggers an olfactory receptor.
sodium channel
T/F: Melatonin is absent form the system or undetectably low during daytime.
true
