Chapter 10: Functional Organization Of Nervous Tissue

Front 1

What are the functions of the nervous system?

Back 1

sensory input

integration: processes and responds to sensory input

control of muscles and glands

homeostasis

mental activities

Front 2

The nervous system that transmits action potentials from sensory receptors to the CNS.

Back 2

sensory devision of the PNS

Front 3

The nervous system that carries action potentials away from the CNS in cranial or spinal nerves.

Back 3

motor division of the PNS

Front 4

The nervous system that innervates the skeletal muscle

Back 4

somatic nervous system (of the motor PNS)

Front 5

The nervous system that innervates cardiac muscle, smooth muscle, and glands.

Back 5

autonomic nervous system (of the motor PNS)

Front 6

The nervous system that is most active during physical activity (fight or flight division).

Back 6

sympathetic nervous system (of the ANS)

Front 7

The nervous system that regulates resting functions (rest and digest division).

Back 7

parasympathetic nervous system (of the ANS)

Front 8

The nervous system that controls the digestive system.

Back 8

enteric nervous system (of the ANS)

Front 9

cells that surround neurons; account for over half of the brain's weight

Back 9

glial cells

Front 10

Less than ___% of the brain is extracellular space.

Back 10

20

Front 11

primary site of protein synthesis that contains a nucleus and nucleolus

Back 11

cell body (soma)

Front 12

An aggregate of rough ER and free ribosomes that is the site of protein synthesis

Back 12

Nissl substance

Front 13

A neuron has no ______ centrioles and has a ______ nature.

Back 13

centrioles

amitotic

Front 14

Clusters of cell bodies in the CNS are called ____ and in the PNS _____.

Back 14

nuclei

ganglia

Front 15

part of the neuron where the axon originates; where the action potential is generated

Back 15

trigger zone

Front 16

Bundles of processes are called _______ in the CNS and _____ in the PNS.

Back 16

nerve tracts

nerves

Front 17

A neuron is several dendrites and a single axon; includes interneurons and most neurons

Back 17

multipolar neuron

Front 18

Neurons that have a single axon and dendrite; components of sensory organs

Back 18

bipolar neurons

Front 19

A neuron that has a single axon; most sensory neurons.

Back 19

unipolar neurons

Front 20

What are the four functions of glial cells?

Back 20

-provide a supportive scaffolding for neurons

-segregate and insulate neurons

-guide young neurons to the proper connections

-promote health and growth

Front 21

Most abundant, versatile, and highly branched glial cell of the CNS

Back 21

astrocyte

Front 22

Astrocytes cling to ____ and their _____, and cover ____. They support and brace neurons and _____. They anchor neurons to their ______. The also influence the functioning of the _____, guide migration of ________, mop up leaked _____ and recycle _____, and isolate damaged tissue and limit the spread of _________.

Back 22

neurons

synaptic endings

blood vessels

nutrient supplies

blood-brain barrier

young neurons

potassium ions

neurotransmitters

inflammation

Front 23

Glial cell of the CNS that ranges in shape from squamous to columnar and many are ciliated

Back 23

ependymal cells

Front 24

Ependymal cells line the _____ of the brain and the _____ of the spinal cord. Some are specialized (called ______) to produce CSF. They help circulate CSF using their _____.

Back 24

ventricles

central canal

choroid plexuses

cilia

Front 25

Glial cell of the CNS that is a small, ovoid cell with spine processes; a phagocyte that monitors the health of neurons

Back 25

microglia

Front 26

glial cell of the CNS that forms myelin sheaths around the axons of several CNS neurons

Back 26

oligodendrocyte

Front 27

glial cell of the PNS that forms a myelin sheath around part of the axon of a PNS neuron

Back 27

schwann cell

Front 28

glial cell of the PNS that supports and nourishes neuron cell bodies within the ganglia

Back 28

satellite cells

Front 29

The myelin sheath is made up of the _____ of the schwann cell/oligodendrocyte. The functions of the myelin sheath are to ____ the axon, electrically _____ the fibers from one another, and increase the ____ of nerve impulse transmission.

Back 29

plasma membrane

protect

insulate

speed

Front 30

gaps in the myelin sheath

Back 30

nodes of ranvier

Front 31

Consists of myelinated axons that propagate action potentials and form nerve tracts in the CNS or nerves in the PNS

Back 31

white matter

Front 32

Collections of neuron cell bodies or unmyelinated axons; forms the cortex and nuclei in the CNS and ganglia in the PNS

Back 32

gray matter

Front 33

_____, _____, and ______ ions are in much great concentration outside the cell than inside. _____ ions and _____ molecules are in much greater concentration inside the cell than outside.

Back 33

sodium

calcium

chloride

potassium

negatively-charged

Front 34

Concentration gradients of ions results mainly from the ______.

Back 34

sodium-potassium pump

Front 35

Permeability characteristics of the plasma membrane are determined by what two things?

Back 35

leak channels

gated ion channels

Front 36

____ channels are always open. There are more _________ channels then there are ________ channels. Thus, the plasma membrane is more permeable to ___ than ___.

Back 36

leak

potassium leak

sodium leak

potassium

sodium

Front 37

channels that open or close with the binding of a specific ligand

Back 37

ligand-gated channels

Front 38

channels that open and close in response to small voltage changes across the plasma membrane; common in nervous and muscle tissues

Back 38

voltage-gated ion channels

Front 39

charge difference across the plasma membrane when the cell is not being stimulated

Back 39

resting membrane potential

Front 40

Inside of the cell is more _____ charged due to the tendency of ____ to diffuse out of the cell.

Back 40

negatively

K+

Front 41

brief period of hyper polarization following repolarization

Back 41

afterpotential

Front 42

time during an action potential when a second stimulus (no matter how strong) cannot initiate another action potential

Back 42

absolute refractory period

Front 43

time during which a stronger-than-threshold stimulus can evoke another action potential

Back 43

relative refractory period

Front 44

The ______ is directly proportion to stimulus strength and to the size of the graded potential.

Back 44

action potential frequency

Front 45

A _____ stimulus produces a grade potential. A _____ stimulus produces a single action potential. A _____ stimulus increases action potential frequency as it increase in strength. And a _____ stimulus produces a maximum frequency of action potentials.

Back 45

subthreshold

threshold

submaximal

maximal/supramaximal

Front 46

Reversal of the direction of the action potential is prevented by the _____.

Back 46

absolute refractory period

Front 47

Action potentials occur most rapidly in ______, _________ axons.

Back 47

myelinated

large-diameter

Front 48

In an unmyelinated axon, APs are generated immediately ___________. In a myelinated axon, APs are generated at ________.

Back 48

adjacent to previous APs

successive nodes of ranvier

Front 49

gap junctions in which tubular proteins called connexons allow ionic currents to move between cells

Back 49

electrical synapses

Front 50

In electrical synapses, an AP in one cell generates an _____ current that causes an AP in an _______. The APs are conducted rapidly between cells allowing for ___________. These are common in _______ and many types of ________.

Back 50

ionic

adjacent cell

synchronized activity

cardiac muscle

smooth muscle

Front 51

What are the three anatomical components of chemical synapses?

Back 51

presynaptic terminals, postsynaptic terminals, and synaptic cleft

Front 52

What two ways are used to stop the effect of the neurotransmitter?

Back 52

-breakdown by enzyme

-taken up by presynaptic terminal (re-uptake)

Front 53

substances released from neurons that can presynaptically or postsynaptically influence the likelihood that an AP will be generated

Back 53

neuromodulators

Front 54

a depolarizing graded potential of the postsynaptic membrane

Back 54

EPSP (excitatory postsynaptic potential)

Front 55

a hyperpolarizing graded potential of the postsynaptic membrane

Back 55

IPSP (inhibitory postsynaptic potential)

Front 56

occurs when two or more presynaptic terminals simultaneously stimulate a postsynaptic neuron

Back 56

spatial summation

Front 57

occurs when two or more action potentials arrive in succession at a single presynaptic terminal

Back 57

temporal summation

Front 58

neuronal pathway that has many neurons synapsing with a few neurons

Back 58

convergent pathway

Front 59

neuronal pathway that has few neurons synapsing with many neurons

Back 59

divergent pathway

Front 60

neuronal pathway that has collateral branches of postsynaptic neurons synapsing with presynaptic neurons

Back 60

oscillating circuits