Bio220 Chapter 11

Front 1

Central Nervous system(CNS)

Back 1

consists of the brain and spinal cord and is encased in bone

Front 2

Peripheral Nervous System(PNS)

Back 2

the nervous tissue outside of the CNS, consists of sensory receptors, nerves, ganglia, and plexuses

Front 3

Sensory Division(PNS)

Back 3

transmits action potentials to the CNS and usually consists of single neurons that have their cell bodies in ganglia

Front 4

Motor Division(PNS)

Back 4

carries action potentials away from the CNS in cranial or spinal nerves

Front 5

Somatic Nervous System(MD of PNS)

Back 5

innervates skeletal muscle and is under voluntary control; consists of single neurons that have their cell bodies located within the CNS

Front 6

Autonomic Nervous System(MD of PSN)

Back 6

innervates cardiac mucle, smooth muscles and glands. has two sets of neurons between CNS and effector organs: 1st set of cell bodies in CNS, 2nd set in autonomic ganglia.

Front 7

Sympathetic Division(ANS)

Back 7

most active during physical activity

Front 8

Parasympathetic Division(ANS)

Back 8

regulates resting functions

Front 9

Enteric Nervous System

Back 9

controls digestive system;
plexuses within the wall of the digestive tract. Can control the digestive tract independently of the CNS, but still considered part of ANS because of the parasympathetic and sympathetic neurons that contribute to the plexi.

Front 10

PNS

Back 10

detects stimuli and transmits info to and receives info from CNS

Front 11

CNS

Back 11

processes, integrates, stores and responds to info from PNS

Front 12

Neurons

Back 12

receive stimuli and transmit action potentials

Front 13

Neuron Cell Body(Soma)

Back 13

primary site of protein synthesis

Front 14

Dendrites

Back 14

short, branched cytoplasmic extensions of the cell body tha conduct electrical signals toward the cell body; input

Front 15

Axon

Back 15

cytoplasmic extension of the cell body that transmits action potentials to other cells; output

Front 16

Multipolar Neurons

Back 16

have several dendrites and one axon; most neurons in CNS; motor neurons

Front 17

Bipolar Neurons

Back 17

single axon and dendrite; components of sensory organs; sensory in retina of the eye and nose

Front 18

Pseudo Unipolar neurons

Back 18

single axon; most sensory neurons are pseudo unipolar; single process that divides into two branches. Part that extends to the periphery has dendrite-like sensory receptors

Front 19

Neuroglia

Back 19

nonneural cells that support and aid the neurons of the CNS and PNS

Front 20

Astrocytes

Back 20

provides structural support for neurons and blood vessels, influences blood brain barrier and processes substances that pass through it, isolates damaged tissue and limits spread of inflammation and maintains synaptic function

Front 21

Components of NS

Back 21

Brain, spinal cord, nerves, sensory receptors

Front 22

Sensory receptors

Back 22

ending of neurons or separate, specialized cells that detect such things as temperature, pain, touch, pressure, light, sound, odors

Front 23

Nerves

Back 23

a bundle of axons and their sheaths that connects CNS to sensory receptors, muscles, and glands

Front 24

Cranial nerves

Back 24

originate from the brain; 12 pairs

Front 25

Spinal nerves

Back 25

originate from spinal cord; 31 pairs

Front 26

Ganglion

Back 26

collection of neuron cell bodies outside CNS

Front 27

Plexus

Back 27

extensive network of axons, and sometimes neuron cell bodies, located outside CNS

Front 28

Sensory (afferent)

Back 28

transmits action potentials from receptors to CNS.

Front 29

Motor (efferent)

Back 29

transmits action potentials from CNS to effectors (muscles, glands)

Front 30

Synapse

Back 30

junction of a nerve cell with another cell.

Front 31

Dendritic spines

Back 31

little protuberance where axons synapse with dendrite.

Front 32

Trigger zone

Back 32

site where action potentialsare generated; axon hillock and part of axon nearest cell body

Front 33

Axoplasm

Back 33

moved from cell body toward terminals. Supply for growth, repair, renewal. Can move cytoskeletal proteins, organelles away from cell body toward axon terminals.

Front 34

Interneurons or association neurons

Back 34

within CNS from one neuron to another

Front 35

Blood-brain barrier

Back 35

protects neurons from toxic substances, allows the exchange of nutrients and waste products between neurons and blood, prevents fluctuations in the composition of the blood from affecting the functions of the brain.

Front 36

Ependymal Cells

Back 36

Line brain ventricles and spinal cord central canal. Specialized versions of ependymal form choroid plexuses.

Front 37

Choroid plexus

Back 37

within certain regions of ventricles. Secrete cerebrospinal fluid. Cilia help move fluid thru the cavities of the brain. Have long processes on basal surface that extend within the brain tissue, may have astrocyte-like functions.

Front 38

Microglia

Back 38

specialized macrophages. Respond to inflammation, phagocytize necrotic tissue, microorganisms, and foreign substances that invade the CNS.

Front 39

Oligodendrocytes

Back 39

form myelin sheaths if surrounding axon. Single oligodendrocytes can form myelin sheaths around portions of several axons.

Front 40

Schwann cells or neurolemmocytes

Back 40

wrap around portion of only one axon to form myelin sheath. Wrap around many times. During development, as cells grow around axon, cytoplasm is squeezed out and multiple layers of cell membrane wrap the axon. Cell membrane primarily phospholipid.

Front 41

Satellite cells

Back 41

surround neuron cell bodies in sensory ganglia, provide support and nutrients

Front 42

Myelinated axons

Back 42

Myelin protects and insulates axons from one another, speeds transmission, functions in repair of axons.
Not continuous
Nodes of Ranvier
Completion of development of myelin sheaths at 1 yr.
Degeneration of myelin sheaths occurs in multiple sclerosis and some cases of diabetes mellitus.

Front 43

Unmyelinated axons

Back 43

rest in invaginations of Schwann cells or oligodendrocytes. Not wrapped around the axon; gray matter.

Front 44

Gray matter

Back 44

unmyelinated axons, cell bodies, dendrites, neuroglia. Integrative functions

Front 45

White matter

Back 45

myelinated axons. Nerve tracts propagate actin potentials from one area in the CNS to another

Front 46

Brain Matter

Back 46

gray is outer cortex as well as inner nuclei; white is deeper

Front 47

Spinal Cord Matter

Back 47

white is outer, gray is deeper.

Front 48

PNS gray matter

Back 48

is groups of cell bodies called ganglia

Front 49

Gated ion channels

Back 49

open and close because of some sort of stimulus. When they open, they change the permeability of the cell membrane.

Front 50

Ligand-gated

Back 50

molecule that binds to a receptor; protein or glycoprotein

Front 51

Resting Membrane Potential

Back 51

Number of charged molecules and ions inside and outside cell nearly equal
Concentration of K+ higher inside than outside cell, Na+ higher outside than inside

Front 52

Potential difference

Back 52

unequal distribution of charge exists between the immediate inside and immediate outside of the plasma membrane: -70 to -90 mV

Front 53

Depolarization

Back 53

Potential difference becomes smaller or less polar

Front 54

Hyperpolarization

Back 54

Potential difference becomes greater or more polar

Front 55

All-or-none principle

Back 55

No matter how strong the stimulus, as long as it is greater than threshold, then action potential will occur.

Front 56

Threshold stimulus

Back 56

causes a graded potential that is great enough to initiate an action potential.

Front 57

Subthreshold stimulus

Back 57

does not cause a graded potential that is great enough to initiate an action potential

Front 58

Maximal stimulus

Back 58

just strong enough to produce a maximum frequency of action potentials

Front 59

Submaximal stimulus

Back 59

all stimuli between threshold and the maximal stimulus strength

Front 60

Supramaximal stimulus

Back 60

any stimulus stronger than a maximal stimulus. These stimuli cannot produce a greater frequency of action potentials than a maximal stimulus

Front 61

Connexons

Back 61

protein tubes in cell membrane.

Front 62

Electrical Synapses

Back 62

Gap junctions that allow graded current to flow between adjacent cells. Found in cardiac muscle and many types of smooth muscle. Action potential of one cell causes action potential in next cell, almost as if the tissue were one cell.