Anatomy_Concepts_Ch12-15

Question 1

functions of the nervous system

Answer 1

it uses its millions of sensory receptors to monitor changes occurring both inside and outside the body. each of these changes is called a stimulus, and the gathered information is called sensory input<br></br>it processes and interprets the sensory input and makes decisions about what should be done at each moment, amprocess called integration<br></br>it dictates a response by activating the effector organs, our muscles or glands; the response is called motor output

Question 2

classification of neurons

Answer 2

structural classification: multipolar neurons, bipolar neurons, unipolar neurons (pseudounipolar neurons)<br></br>functional classification: sensory neurons, motor neurons, interneurons

Question 3

neuroglia functions

Answer 3

provide a supportive scaffolding for neurons<br></br>cover all nonsynaptic parts of the neurons, thereby insulating the neurons and keeping the electrical activities of adjacent neurons from interfering with each other

Question 4

neuron/nerve fiber/nerve

Answer 4

a neuron is a nerve cell<br></br>a nerve fiber is a long axon<br></br>a nerve is a collection of axons in the PNS

Question 5

regeneration of an axon in a peripheral nerve

Answer 5

1) the axon becomes fragmented at the injury site<br></br>2) macrophages clean out the dead axon distal to the injury<br></br>3) axon sprouts, of filaments, grow thorugh a regeneration tube formed by Schwann cells<br></br>4) the axon regenerates, and a new myelin sheath forms

Question 6

corticle pathway (slower) which follows the spinal pathway works how?

Answer 6

1) parallel processing. simultaneouly, the nerve impulses travel on an axon branch that extends into the white matter. this ascending axon carries the nerve impulses to the brain.<br></br>2) integration in gray matter. multiple interneurons process the nerve impulses to localize the stimulus, identify its source, and plan a resonse. this complex process enables you to feel the pain<br></br>3) voluntary motor response. a nonreflexive motor response is initiated in the gray matter and transmitted down a descending axon in the white matter to stimulate somatic motor neurons

Question 7

spinal pathway works how?

Answer 7

withdrawal reflex. a painful stimulus triggers nerve impulses in a sensory neuron, which initiate the polysynaptic withdrawal reflex

Question 8

somatic sensory (SS) sensory components

Answer 8

general: touch, pain, pressure, vibration, temperature, and propreoception from the skin, body wall, and limbs<br></br>special: hearing, equilibrium, and vision

Question 9

visceral sensory (VS) sensory components

Answer 9

general: stretch, pain, temperature, chemical changes, and irritation in viscera; nausea and hunger<br></br>special: taste and smell

Question 10

somatic motor (SM) motor components

Answer 10

motor innervation to skeletal muscles

Question 11

visceral motor (VM; autonomic) motor components

Answer 11

motor innervation to smooth muscle, cardiac muscle, and glands

Question 12

functional class–neuron type according to direction of impulse conduction: multipolar

Answer 12

most multipolar neurons are interneurons that conduct impulses within the CNS, integrating sesory input or motor output; may be one of a chain of CNS neurons, or a single neuron connecting sensory and motor neurons<br></br>some multipolar neurons are motor neurons that conduct impulses along the efferent pathways from the CNS to an effector (muscle/gland)

Question 13

functional class–neuron type according to direction of impulse conduction: bipolar

Answer 13

essentially all bipolar neurons are sensory neurons that are locate in some special sense organs. for example, bipolar cells of the retine are involved with the transmission of visual inputs from the eye to the brain (via an intermediate chain of neurons)

Question 14

functional class–neuron type according to direction of impulse conduction: unipolar (pseudounipolar)

Answer 14

most unipolar neurons are sensory neurons that conduct impulses along afferent pathways to the CNS for interpretation. (these sensory neurons are called primary or first-order sensory neurons)

Question 15

structural class–neuron type according to the number of precesses extending from the cell body: multipolar

Answer 15

many processes extend from the cell body; all are dendrites except for a single axon

Question 16

structural class–neuron type according to the number of precesses extending from the cell body: bipolar

Answer 16

two processes extend from the cell body, one is a fused dendrite, the other is an axon

Question 17

structural class–neuron type according to the number of precesses extending from the cell body: unipolar (pseudounipolar)

Answer 17

one process extends from the cell body and forms central and peripheral processes, which together comprise and axon

Question 18

relative abundance and location in human body: multipolar

Answer 18

most abundant in body. major neuron type in the CNS

Question 19

relative abundance and location in human body: bipolar

Answer 19

rare. found in some special sensory organs (olfactory mucosa, eye, ear)

Question 20

relative abundance and location in human body: unipolar (pseudounipolar)

Answer 20

found mainly in the PNS. common only in dorsal root ganglia of the spinal cord and sensory ganglia of cranial nerves

Question 21

primary brain vesicles

Answer 21

prosencephalon (forebrain)<br></br>mesencephalon (midbrain)<br></br>phombencephalon (hindbrain)

Question 22

secondary brain vesicles

Answer 22

presencephalon divides in to the telencephalon (endbrain) and the diencephalon (through-brain)<br></br>mesencephalon remains undivided<br></br>rhombencephalon divides into the metencephalon (afterbrain) and the myelencephalon (brain most like the spinal cord)

Question 23

telencephalon

Answer 23

develops two lateral swellings that look like large mouse earse . these become the large cerebral hemispheres, together called the cerebrum

Question 24

diencephalon

Answer 24

develops three main divisions: the thalamus, the hppothalamus, and the epithalamus

Question 25

mesencephalon

Answer 25

forms the midbrain

Question 26

metencephalon

Answer 26

ventral part becomes the pons, and the dorsal roof develops into the cerebellum

Question 27

myelencephalon

Answer 27

forms the medulla oblongata

Question 28

four parts of the brain

Answer 28

1) brain stem (medulla oblongata, pons, and midbrain)
2) cerebellum
3) diencephalon
4) cerebrum (composed of the two cerebral hemispheres)

Question 29

functions of the brain stem

Answer 29

it acts as a passageway for all the fiber tracts running between the cerebrum and the spinal cord
it is heavily involved with the innervation of the face and head; 10 of the 12 pairs of crainal nerves attach to it
it produces the rigidly programmed, automatic behaviors necessary for survival
it integrates auditory reflexes and visual reflexes

Question 30

four pairs of cranial nerves attach to the medulla

Answer 30

vestibulocochlear nerve (crainal nerve VIII)
glossopharyngeal nerve (cranial nerve IX)
vagus nerve (cranial nerve X)
hypoglossal nerve (cranial nerve XII)

Question 31

brain nuclei in the reticular formation form three columns of gray matter on each side that extend the length of the brain stem

Answer 31

1) the midline raphe nuclei, which are flanked laterally by
2) the medial nuclear group and then
3) the lateral nuclear group

Question 32

"nuclei in the medulla's reticular formation are involved with visceral activities:"

Answer 32

the cardiac center adjusts the force and rate of the heartbeat
the vasomotor center regulates blood pressure by stimulating or inhibiting the contraction of smooth muscle in the walls of blood vessels, thereby constricting or dilating the vessels
the medullary respiratory center controls the basic rhythm and rate of breathing

Question 33

several cranial nerves attach to the pons

Answer 33

trigeminal (cranial nerve V)
abducens (crainal nerve VI)
facial (cranial nerve VII)

Question 34

each cerebellar hemisphere is subdivided into three lobes:

Answer 34

large anterior and posterior lobes, and the small flocculonodular lobe

Question 35

information is processed by the cerebellum in the folliwing way:

Answer 35

the cerebellum receives information from the cerebrum on the movements being planned
the cerebellum compares these planned movements with current body position and movements
the cerebellum sends instructions back to the cerebral cortex on how to resolve any differences between the intended movements and current position

Question 36

functions of the hypothalamus

Answer 36

control of the autonomic nervous system
regulation of body temperature
regulation of hunger and thirst sensations
regulation of sleep-wake cycles
control of the endocrine system
control of emotional responses
control of motivational behavior
forrmation of memory

Question 37

five major lobes of each cerebral hemisphere:

Answer 37

frontal lobe, parietal lobe, occipital lobe, temporal lobe, insula

Question 38

information is processed through regions of the cerebral cortex in the following hierarchical manner

Answer 38

1. sensory information is received by the primary sensory cortex, and the arrival of this information results in awareness of the sensation
2. the information is relayed to the sensory association area that gives meaning to the sensory input
3. the multimodal association areas receive input in parallel from multiple sensory association areas, integrating all of the sensory input to create a complete understanding of the sensory information.  these regions also integrate sensory input with past experience and develop a motor response
4. the motor plan is enacted by the motor cortex

Question 39

primary somatosensory cortex

Answer 39

receives information from the geeral somatic senses (touch, pressure, vibration, pain, and temperature from the skin and proprieception from the muscles and joints) and enables conscious awareness of these sensations

Question 40

sensory homunculus

Answer 40

"""little man"", map of the primary sensory cortex"

Question 41

contralateral projection

Answer 41

the right cerebral hemisphere receives its sensory input from the left side of the body and the left cerebral hemisphere receives its sensory input from the right side of the body

Question 42

somatosensory association cortex

Answer 42

lies posterior to and communicates with the primary somatosensory cortex, integrates sensory inputs (touch, pressure, and others) into a comprehensive understand of what is being felt

Question 43

primary visual cortex

Answer 43

"posterior and medial part of the occipital lobe, much of it buried within the deep carcarine sulcus (""spur-shaped""), receives visual information that originates from the retina of the eye, exhibits contralateral projection"

Question 44

visual association area

Answer 44

surrounds that primary visual cortex and covers much of the occipital lobe, continues the processing of visual information by analyzing color, form, and movement

Question 45

primary auditotry cortex

Answer 45

functions in censcious awareness of sound, in relation to loudness, rhythm, and pitch, located on teh superior edge of the temporal lobe, primarily inside the lateral sulcus

Question 46

auditory association area

Answer 46

lies just posterior and lateral to the primary auditory area, permits the evaluation of a sound

Question 47

sensory areas

Answer 47

somatosensory areas
visual areas
auditory areas
vistibular (equilibrium) cortex
gustatory cortex
olfactory cortex
visceral sensory area

Question 48

motor areas (list)

Answer 48

"primary motor cortex
premotor cortex
frontal eye field
Broca's area"

Question 49

multimodal association areas (list)

Answer 49

posterior association area
anterior association area
limbic association area

Question 50

basal nuclei (parts)

Answer 50

"caudate ""tail like"" nucleus, putamen ""pod"", globus pallidus ""pale globe"""

Question 51

meninges (functions)

Answer 51

cover and protect the CNS
enclose and protect the blood vessels that supply the CNS
contain the cerebrospinal fluid

Question 52

meninges (list)

Answer 52

from external to internal: dura mater, arachnoid mater, and pia mater

Question 53

cerebrospinal fluid (functions)

Answer 53

CSF provides a liquid medium that surrounds and gives buoyancy to the CNS.  the brain and spinal cord actually float in the CSF, which prevents these delicate organs from being crushed under their own weight.
the layer of CSF surrounding the CNS resists compressive forces and cusions the brain and spinal cord from blows and jolts.
CSF helps to nourish the brain, to remove wastse produced by neurons, and to carry chemical signals such as hormones between different parts of the central nervous system.  although similar in composition to the blood plasma from which it arises, CSF contains more sodium and chloride ions and less protein.

Question 54

CSF circulation

Answer 54

1) CSF is produced by the choroid plexus of each ventricle
2) CSF flows through the ventricles and into the subarachnoid space via the median and lateral apertures. Some CSF flows through the central canal of the spinal cord.
3) CSF flows through the subarachnoid space
4) CSF is absorbed into the dural venous sinuses via the arachnoid granulations

Question 55

spinal cord (functions)

Answer 55

1) through the spinal nerves that attach to it, the spinal cord is involved in the sensory and motor innervation of the entire body inferior to the head.
2) through the ascending and descending tracts traveling within its white matter, the spinal cord provides a two-way conduction pathway for signals between the body and the brain.
3) through sensory and motor integration in its gray matter, the spinal cord is a major center for reflexes.

Question 56

three funiculi

Answer 56

"""long ropes"": dorsal (posterior) funiculus, ventral (anterior) funiculus, and lateral funiculus"

Question 57

four zones of spinal cord gray matter

Answer 57

somatic sensory (SS), visceral sensory (VS), visceral motor (VM), and somatic motor (SM)

Question 58

features of the ascending and descending pathways:

Answer 58

most pathways cross from one side of the CNS to the other, or decussate, at some point along their course
most pathways consist of a chain of two or three serially linked neurons that contribute to successive tracts along a given pathway
most pathways are spatially arranged in a specific way, according to the body region they supply. for example, in one ascending tract, the axons transmitting impulses from the superior parts of the body lie lateral to the axons carrying impulses from the inferior body parts
all pathways are bilaterally symetrical, occuring on both the right and left side of the brain or spinal cord

Question 59

three main ascending pathways

Answer 59

spinocerebellar pathway, dorsal column pathway, spinothalamic pathway

Question 60

In the dorsal column pathway:

Answer 60

the axons of first-order neurons, the sensory neurons, enter the spinal cord and send an axonal branch up one of the dorsal white column tracts, either the medial fasciculus gracilis or the lateral fasciculus cuneatus.  these axons ascend in the spinal tract to the medulla oblongata.
in the medulla oblongata, these axons synapse with second-order neurons in the nucleus gracilis or nucleus cuneatus.  axons from these brain nuclei form a tract called the medial lemniscus tract, which decussates in the medulla and then ascends through the pons and midbrain to the thalamus.
third-order neurons originating in the thalamus send axons to the primary sematosensory cortex on the postcentral gyrus, where the sensory information is processed, resulting in awareness of precisely localized sensations.

Question 61

In the spiothalamic pathway:

Answer 61

the axons of first-order sensory neurons enter the spinal cord, where they synapse on interneurons in the dorsal gray horn.
axons of the second-order neurons decussate in the spinal cord, enter the lateral and ventral funicula as the spinothalamic tract, and ascend to the thalamus.
axons from third-order neurons in the thalamus project to the primary somatosensory cortex on the postcentral gyrus, where the information is processed into the consious sensation.  the brain interprets the sensory inforamiton carried by the spinothalamic pathway as unpleasant--pain, burns, cold, and so on.

Question 62

In the pyramidal tracts:

Answer 62

the axons of pyramidal cells, the upper motor neurons, descend from the cerbral motor cortex through the brain stem to the spinal gray matter--mostly to the ventral horns.
in the ventral horn, the axons either synapse with short interneurons that activate somatic motor neurons or synapse directly on somatic motor neurons, the lower motor neurons.

Question 63

indirect motor pathways include:

Answer 63

tectospinal tract (from the superior colliculus, the tectum of the midbrain)
vestibulospinal tract (from the vestibular nuclei)
rubrospinal tract (from the red nucleus)
reticulospinal tract (from the reticular formation)
these tracts stimulate body movements that are subconscieus, coarse, or postural

Question 64

classification of receptors

Answer 64

functional classification: according to their location or the type of stimulus they detect
location of receptors (exteroceptors, interoceptors, proprioceptors)
stimulus type (mechanoreceptors (e.g. baroreceptor), thermoreceptors, chemoreceptors, photoreceptors, nociceptors)
structural classification: (free nerve endings) and (encapsulated nerve endings surrounded by a capsule of connective tissue)

Question 65

main types of encapsulated nerve endings

Answer 65

"tactile (Meissner's) corpuscles
lamellar (Pacinian) corpuscles
bulbous corpuscles (Ruffini endings)
proprioceptors"

Question 66

types of joint kenesthetic receptors are present within each joint capsule

Answer 66

lamellar (Pacinian) corpuscles
bulbous corpuscles (Ruffini endings)
free nerve endings
receptors resembling tendon organs

Question 67

I-XII cranial nerves

Answer 67

I. Olfactory
II. Optic
III. Oculomotor
IV. Trochlear
V. Trigeminal
VI. Abducens
VII. Facial
VIII. Vestibulocochlear
IX. Glossopharyngeal
X. Vagus
XI. Accessory
XII. Hypoglossal

Question 68

components of the brachial plexus, from medial to lateral

Answer 68

Vetral rami.  the ventral rami from spinal segments C5-T1 form the roots of the brachial plexus
Trunks.  the ventral rami merge to form three trunks
Divisions.  each trunk splits into two divisions, anterior and posterior
Cords.  these six divisions then converge to form three cords

Question 69

cerebral cortex function (functional area): frontal lobe

Answer 69

"voluntary movement (primary motor cortex)
planning movement (premotor cortex)
eye movement (frontal eye field)
speech production (Broca's area)
executive cognitive functions (anterior association area)
emotional response (limbic association area)"

Question 70

cerebral cortex function (functional area): parietal lobe

Answer 70

"general somatic sensation (somatosensory cortex and association area)
spatial awareness of objects, sounds, body parts (posterior association area)
understanding speech (Wernicke's area)"

Question 71

cerebral cortex function (functional area): occipital lobe

Answer 71

vision (visual cortex and association areas)

Question 72

cerebral cortex function (functional area): temporal lobe

Answer 72

hearing (auditory cortex and association area)
smell (olfactory cortex)
object identification (posterior association area)
emotional response, memory (limbic association area)

Question 73

cerebral cortex function (functional area): insula

Answer 73

taste (gustatory cortex)

Question 74

cerebral white matter function (functional area): commissural fibers

Answer 74

connect the corresponding cortices of the two hemispheres

Question 75

cerebral white matter function (functional area): association fibers

Answer 75

connect the cortex of the different parts of same hemisphere

Question 76

cerebral white matter function (functional area): projection fibers

Answer 76

connect the cortex to more caudal parts of the CNS

Question 77

deep cerebral gray matter function (functional area): basal nuclei (ganglia)

Answer 77

control movements in conjunction with the motor cortex

Question 78

deep cerebral gray matter function (functional area): basal forebrain nuclei

Answer 78

perform major role in arousal, learning, memory, and motor control; rich in cholinergic fibers

Question 79

deep cerebral gray matter function (functional area): claustrum

Answer 79

function unclear; may integrate information between the cerebral cortex and the limbic system

Question 80

brain stem: medulla oblongata

Answer 80

contains project fibers
site of decussation of the pyramids
relays ascending sensory pathways transmitting impulses from skin and proprioceptors through nuclei cuneatus and gracilis
relays sensory information to the cerebellum through inferior olivary nuclei
contains nuclei of cranial nerves VIII-X and XII
contains visceral nuclei controlling heart rate, blood vessel diameter, respiratory rate, vomiting, coughing, etc.

Question 81

brain stem: pons

Answer 81

contains projection fibers
pontine nuclei relay information from the cerebrum to the cerebellum
contains nuclei of cranial nerves V-VII
contains reticular formation nuclei

Question 82

brain stem: midbrain

Answer 82

contains projection fibers (e.g., cerebral peduncles contain the fibers of the pyramidal tracts)
contains subcortical motor centers (substantia negra and red nuclei)
contains nuclei for cranial nerves III and IV
contains visual (superior colliculi) and auditory (inferior colliculi) reflex centers

Question 83

brain stem: reticular formation--a functional system

Answer 83

maintains cerebral cortical alertness (reticular activating system)
filters out repetitive stimuli
helps regulate skeletal and visceral muscle activity and modulate pain

Question 84

cerebellum: cerebullum

Answer 84

processes input from cerebral motor cortex, proprioceptors, and visual and equilibrium pathways
provides output to cerebral motor cortex and subcortical motor centers that result in smooth, coordinated skeletal muscle movements
resposible for balance and posture

Question 85

diencephalon: thalamus

Answer 85

relays sensory impulses to cerebral cortex for interpretation
relays impulses between cerbral cortex and subcortical motor centers, including basal nuclei (ganglia) and cerebellum
involved in memory processing

Question 86

diencephalon: hypothalamus

Answer 86

chief inegration center of autonomic (involuntary) nervous system
regulates body temperature, food intake, water balance, thirst, and biological rythms and drives
regulates hormonal output of anterior pituitary gland
acts as an endocrine organ producing posterior pituitary hormones AHD and oxytocin

Question 87

cerebral hemispheres: cortical gray matter

Answer 87

localizes and interprets sensory inputs
controls voluntary and skilled skeletal muscle activity
functions in intellectual and emotional processing

Question 88

cerebral hemispheres: basal nuclei (ganglia)

Answer 88

subcortical motor centers help control skeletal muscle movements

Question 89

(multi): limbic system--a functional system

Answer 89

includes cerebral and diencephalon structures (cingulate gyrus, hippocampal formation, amygdaloid body, hypothalamus, and anterior thalamic nuclei)
mediates emotional respnose
forms and retrieves memories

Question 90

somatic motor innervation: somatic motor

Answer 90

targets skeletal muscle
one-neuron pathway
1) cell body of the somatic motor neuron is located in the ventral horn of the gray matter
2) a long myelinated axon extends out from the ventral root to innervate skeletal muscle cells. neurotransmitter is acetylcholine

Question 91

autonomic innervation: sympathetic division of ANS

Answer 91

targets smooth muscle, cardiac muscle, and glands
two-neuron pathway, synapse in an autonomic ganglion
1) cell obdies of preganglionic sympathetic neurons are located in the lateral horn of the gray matter from T1 to L2
2) the myelinated preganglionic axon synapses with the postganglionic neuron in an autonomic ganglion located adjacent to the spinal column. neurotransmitter is acetylcholine
3) a long nonmylinated postganglionic axon extends from the autonomic ganglion to the target organ. neurotransmitter is norepinephrine
4) preganglionic sympathetic axons emerge from T8-L1 to innervate the adrenal medulla, a specialized sympathetic ganglion. adrenal medulla cells release epinephrine and nopepinephrine into blood stream

Question 92

autonomic innervation: parasymathetic division of ANS

Answer 92

targets smooth muscle, cardiac muscle, and glands
two-neuron pathway, synapse in an autonomic ganglion
1) cell bodies of preganglionic parasympathetic neurons are located in the gray matter of the brain stem (CN III, VII, IX, X) and the sacral region of the spinal cord (S2-S4)
2) the myelinated preganglionic axon synapses with the postganglionic neuron in an autonomic ganglion close to or within the target organ. neutotransmitter is acetylcholine
3) a short nonmylinated postganglionic axon innervates the target organ. neurotransmitter is acetylcholine

Question 93

preganglionic axons follow one of three sympathetic pathways:

Answer 93

1) the preganglionic axon synapseswith a postganglionic neuron in the sympathetic trunk ganglion at the same level and exits via the gray ramus communicans into the spinal nerve at that level
2) the preganglionic axon ascends or descends in the sympathetic trunk to synapse in another thrunk ganglion. the postganglionic fiber exits the sympathetic trunk via the gray ramus communicans at the level of the synapse
3) the preganglionic axon passes through the sympathetic trunk, exits on a splanchnic nerve, and synapses in a collateral ganglion. the postsynaptic fiber extends from the collateral ganglion to the visceral organ via an autonomic nerve plexus