The Nervous System

Front 1

basic structure of a neuron

Back 1

cell body (perikaryon, soma_

dendrites

axon

Front 2

arachnoid mater

Back 2

-middle of 3 layers of meninges surrounding the brain and spinal cord

Front 3

cell body of the neuron

Back 3

-aka perikaryon

-aka soma

-single, central nucleus with large nucleoulus

-cytoskeleton of neurofibrils

-endoplasmic reticulum compartmentalized into nissl bodies

Front 4

dendrites

Back 4

-vast number of short dendrites

-for receiving signals

-usually not myelinated (however in the sensory portion often myelinated)

Front 5

axon

Back 5

-single axon (aka nerve fiber) arising from axon hillock for rapid conduction

-axoplasm, axolemma, and synaptic vesicle

-often myelinated

Front 6

classifications of neurons based on function

Back 6

-sensory (afferent) neurons

-interneurons

-motor (efferent) neurons

Front 7

classifcation of neurons based on structure

Back 7

-multipolar neuron

-bipolar neuron

-unipolar

Front 8

sensory (afferent neurons)

Back 8

-detect changes in the environment

-transmit information to the brain or spinal cord

Front 9

interneurons

Back 9

-lie between sensory and motor pathways in the central nervous system

-90% of neurons are interneurons

-process, store and retrieve information

Front 10

motor (efferent) neurons

Back 10

-send signals to muscle and gland cells

-organs that carry out responses are called effectors

Front 11

multipolar neurons

Back 11

-many dendrites/one axon

-most common

Front 12

bipolar neuron

Back 12

-one dendrite/one axon

-olfactory, retina, ear

Front 13

unipolar neuron

Back 13

-long myleinated fiber bypassing soma

-sensory from skin and organs to spinal cord

Front 14

action potential

Back 14

-the depolarization of a neuron (of the membrane of along the neuron)

-when Na channels open Na rushes in and K pushes out, this change in the membrane charge is action potential

-in unmyelinated fibers action potential occurs in one spot (the trigger zone beings chain reaction that travels to end of axon)

-in myelinated fibers saltatory conduction occurs

Front 15

characteristics of an action potential

Back 15

-follows an all-or-none law

-nondecremental (do not get weaker with distance)

-irreversible (once started goes to completion and cannot be stopped)

Front 16

synapse

Back 16

-the space between neurons

-the function point of "contact"

-may be axodendritic, axosomatic, or axoaxonic

Front 17

urotransmitter

Back 17

chemical signals which are released from one neuron at the presynaptic nerve terminal and either inhibit or excite the post synaptic membrane

Front 18

saltatory conduction

Back 18

-a form of nerve impulse conduction which the action potential jumps from one of Ranvier's node to the next rather than traveling the entire length of the nerve fiber

Front 19

effects of neurotransmitters

Back 19

-neurotransmitters either excite or inhibit

-inhibition happens via hyperpolarization of the membrane (making it harder for the membrane to depolarize)

Front 20

how are sensory receptors classified

Back 20

-location

-stimulus

Front 21

receptors classified by location

Back 21

-exteroceptors

-visceroceptors

Front 22

exteroceptors

Back 22

-a sensory receptor that receives external stimuli

-located in the skin, oral cavity, eyes, ears, and nose

Front 23

visceroceptors

Back 23

-a sensory receptor located with body organs that respond to information concerning the internal environment

Front 24

receptors classified by stimulus

Back 24

-mechanoreceptors

-thermoreceptors

-nociceptors

-proprioceptors

-photoreceptors

-chemoreceptors

Front 25

what is a mechanoreceptor

Back 25

-changing the shape of the cell causes depolarization

Front 26

examples of mechanoreceptors

Back 26

-root hair plexuses

-merkle's discs

-meissner's corpuscles

-end organs of ruffini

-pacinian corpuscles

-free nerve endings

Front 27

examples of thermoreceptors

Back 27

-krause

-ruffini

Front 28

nocioceptors

Back 28

respond to any stimulus strong enough to cause tissue damage

Front 29

proprioceptors

Back 29

-relaying information to the central nervous system about the position of the structure in space

Front 30

example proprioceptors

Back 30

-muscle spindles

-tendon organs (golgi)

-joint kinesthetic receptors

-maculae

-cristae

Front 31

example photoreceptors

Back 31

-rods

-cones

Front 32

example chemoreceptors

Back 32

-gustatory cells

-olfactory cells

-chemoreceptors at various locations in extracellular fluid (keep in mind there are no chemoreceptors for Na+ but there are osmolality detectors)

Front 33

what are the main components of the central nervous system

Back 33

the brain and spinal cord (also remember meninges, ventricles, cerebrospinal fluid, and blood supply)

Front 34

the main components of the brain

Back 34

-the cerebrum

-the cerebellum

-the diencephalon

-the brain stem

Front 35

afferent route of the somatic nervous system

Back 35

-the sensory (afferent) division carries sensory signals from receptor to the central nervous system

-somatic sensory - skin,muscles, bones, and joints

Front 36

efferent route of the somatic nervous system

Back 36

-the motor (efferent) division carries motor signals to the central nervous system to effectors (glands and muscles)

-somatic motor supplies skeletal muscles

Front 37

spinal nerves

Back 37

-paired mixed nerves which arise from the spinal cord

-the ventral route is motor: the somatic cell bodies are in the anterior grey horn, the visceral cell bodies are in the lateral grey horn

-the dorsal route is sensory

Front 38

cranial nerves in general

Back 38

12 pairs of nerves that arise from the brain

Front 39

autonomic sensory division

Back 39

-the sensory (afferent) division carries sensory signals from receptors to the central nervous system

-visceral sensory - viscera

Front 40

motor sensory division

Back 40

-the motor (efferent) division carries motor signals from the central nervous system to the effectors (glands and muscles)

-visceral motor supplies cardiac, smooth, and glands

Front 41

sympathetic nervous system

Back 41

-tends to around

-fight, flight, or heavy exercise

Front 42

parasympathetic

Back 42

-restorative activities

-digestion, restorative activities, immunity

Front 43

meninges

Back 43

-connective tissue which cover and protect the brain and spinal cord

Front 44

meningitis

Back 44

inflammation of the meninges

Front 45

the 3 layers of the meninges

Back 45

-dura mater

-arachnoid

-pia mater

Front 46

dura mater

Back 46

-outermost, thickest, toughest layer of meninges

-between the dura and the vertebra spidural space

Front 47

arachnoid

Back 47

-the middle layer of the meninges

-contains spinderweb-like filaments

-contains the roots of the spinal nerves

Front 48

subarachnoid space

Back 48

-between the pia mater and arachnoid

-contains cerebrospinal fluid

Front 49

pia mater

Back 49

-the inner, thin layer of the meninges which tightly adhere to the surface of the brain and spinal cord

Front 50

the cerebral lobes are

Back 50

-frontal

-parietal

-occipital

-temporal

-insula

Front 51

the frontal lobe

Back 51

-contains voluntary motor functions

-areas for planning, mood, and smell

Front 52

the parietal lobe

Back 52

-contains areas for sensory reception and integration of sensory information

Front 53

the occipital lobe

Back 53

-the visual center of the brain

Front 54

the temporal lobe

Back 54

-hearing

-smell

-learning

-memory

Front 55

insula

Back 55

little is known about the insula

Front 56

the cortex

Back 56

-the cerebral cortex is the outer grey matter portion of the cerebrum

Front 57

the blood brain barrier

Back 57

-tightly joined endothelium which is permeable to lipid-soluble materials

-circumventricular organs in the 3rd and 4th ventricle s are breaks int he barrier where hte blood has direct access

-blood-cerebrospinal fluid barrier at the choroid plexus is ependymal cells joined by tight junctions

Front 58

choroids plexus

Back 58

-network of capillaries located in the roof of ventricles

-contributes to the production of cerebrospinal fluid

Front 59

diencephalon

Back 59

-serves as a passageway between the brain stem and the cerebrum

-contains the thalamus, hypothalamus, and pineal gland

Front 60

thalamus

Back 60

-a relay station for regulating sensory inputs to the cerebrum

-a circular structure ventral to the corpus callosum

-interconnected to the limbic system

Front 61

hypothalamus

Back 61

-a bridge between the nervous system and the endocrine system

-synthesizes and produces hormones to stimulate/inhibit cells in the anterior pituitary gland

-located between the thalamus and the pituitary gland (forms the walls and floor of the 3rd ventricle)

Front 62

pineal gland

Back 62

-secretes melatonin (in high concentrations in the absence of sunlight - in the presence of sunlight produces serotonin)

-small "bean" shaped structure located caudal to the thalamus

Front 63

the brain stem consists of

Back 63

-midbrain

-pons

-medulla oblongata/vital centers

Front 64

midbrain

Back 64

located between the pons and the cerebrum (between the pons and the diencephalon)

Front 65

pons

Back 65

-bulge in the brain stem located just rostral to the medulla oblongata

-pathways in and out of the cerebellum

-ascending tracts = sensory tracts

-descending tracts = motor tracts

-nuclei concerned with sleep, hearing, balance, taste, eye movements, facial sensations, respiration, swallowing, bladder control, and posture

Front 66

medulla oblongata

Back 66

-the area of the brain stem that connects to the spinal cord

-contains ascending and descending nerve tracts

-contains vital centers of the brain

Front 67

vital centers within the medulla oblongata

Back 67

-cardiac center adjusts rate and force of heart beat

-vasomotor center adjusts blood vessel diameter

-respiratory center controls rate and depth of breathing

-also reflexes for coughing, sneezing, gagging, swallowing, vomiting, salivation, sweating, movements of tongue and head

Front 68

cardiac center of the medulla oblongata

Back 68

adjusts rate and force of heart beat

Front 69

vasomotor center of the medulla oblongata

Back 69

adjust blood vessel diameter

Front 70

respiratory centers of the medulla oblongata

Back 70

control rate and depth of breathing

Front 71

cerebellum

Back 71

-located caudally to cerebrum - sits atop the 4th ventricle

-white matter (arbor vitae) visible in sagittal section

-coordinates movements, balances, postures, and complex reflexes

Front 72

sulci

Back 72

the shallow depressions in the surface of the cerebrum between the gyri

Front 73

gyri

Back 73

the hills or ridges on the surface of the cerebrum

Front 74

arbor vitae

Back 74

the cerebellar white matter grossly visible when the cerebellum is sliced

Front 75

folia

Back 75

parallel surface folds made of grey matter on the cerebellum

Front 76

ventricles

Back 76

-internal chambers within the central nervous system

-lined with ependymal cells and containing choroid plexus of capillaries that produce cerebrospinal fluid

Front 77

the order of cerebrospinal fluid follows through the brain

Back 77

-lateral ventricles

-3rd ventricle

-cerebral aqueduct

-fourth ventricle

-central canal

Front 78

lateral ventricle

Back 78

-found inside the cerebral hemispheres

Front 79

3rd ventricle

Back 79

single vertical space under the corpus callosum

Front 80

cerebral aqueduct

Back 80

-runs through the midbrain

-channel connecting the 3rd and 4th ventricle and containing cerebrospinal fluid

Front 81

fourth ventricle

Back 81

small chamber between the pons and cerebellum

Front 82

central canal

Back 82

runs through the center of the spinal cord

Front 83

grey matter

Back 83

-contains most of the neuron cell bodies

-where many nerve impulses are initiated

Front 84

where is grey matter found in the spinal cord

Back 84

-the medulla (inner portion) of spinal cord

-forms a butterfly shape in the spinal cord

Front 85

where is grey matter found in the cerebrum and cerebellum

Back 85

in the cortex (outer portion) of the cerebrum and cerebellum

Front 86

the dorsal horn of the grey matter in the spinal cord

Back 86

carries sensory impulses up to the brain

Front 87

the ventral horn of grey matter in the spinal cord

Back 87

carries motor impulses out to the rest of the body

Front 88

white matter

Back 88

-consists mainly of myelinated nerve fibers

-it is the wiring that carries impulses in and out of grey matter

-the myelin sheath that covers the nerve fibers it the white apperance

Front 89

where is white matter found in the cerebrum and cerebellum?

Back 89

in the medulla (inner portion) of the cerebrum and cerebellum

Front 90

where is white matter found in the spinal cord

Back 90

the in the cortex (outer portion) of the spinal cord

Front 91

nerve

Back 91

a bundle of nerve fibers in connective tissue outside the central nervous system

Front 92

neuron

Back 92

the basic functional unit of the nervous system - a nervous cell

Front 93

tract

Back 93

a bundle of myelinated nerve fibers inside the central nervous system

Front 94

different types of tracts

Back 94

-projection tracts

-commissural tracts

-association tracts

Front 95

commissural tracts

Back 95

white-matter structures in the corpus callosum which connect the 2 hemispheres of the brain

Front 96

projection tracts

Back 96

white matter structures in the corpus callosum which connects each region of the brain to other parts of the brain or spinal cord

Front 97

association tracts

Back 97

white matter structures in the corpus callosum which connects regions within the same hemisphere of the brain

Front 98

ganglia

Back 98

-clusters of neuron cell bodies outside the central nervous system

Front 99

the difference between chain ganglion and dorsal root ganglion?

Back 99

the chain ganglion have synapses that release neurotransmitters but the dorsal root ganglion do not contain synapses

Front 100

nuclei

Back 100

clusters of neuron cell bodies inside the central nervous system

Front 101

gyrencephalic

Back 101

-the convoluted surface of the brain

-mammalian brain containing gyri and sulci

Front 102

lissencephalic

Back 102

-the smooth outer surface of the brain

-brains of small mammals with smooth surfaces

Front 103

longitudinal fissure

Back 103

separates the 2 cerebral hemispheres

Front 104

corpus callosum

Back 104

-large band of nervous tissue that connects the 2 hemispheres

-connects bundle of tracts connecting corresponding areas of hemisphere

Front 105

optic chiasm

Back 105

-the crossing point of the optic nerve

-in mammals with forward facing eyes the medial area of the field of vision crosses over to the opposite hemisphere

-the lateral view goes directly back to the corresponding side of the occipital lobe