Histo Lecture 1

Question 1

two types of cells found in nervous tissue

Answer 1

1. nerve cells or neurons

2. neuroglia, glia, or supporting cells

Question 2

special characteristics of neurons

Answer 2

1. extreme longevity
2. most are amitotic
3. high metabolic rate

Question 3

neurons are made up of ____ and ____

Answer 3

1. neuron cell body (perikaryon)

2. processes: dendrite(s) or axon (nerve fiber)

Question 4

biosynthetic center of a neuron

Answer 4

neuron cell body (perikaryon)

Question 5

Rough ER and ribosomes in the perikaryon create ____- darkened areas within the cytoplasm which can be readily seen with a hematoxylin stain

Answer 5

Nissl bodies

Question 6

the perikaryon is always ____ and has no ____

Answer 6

unmyelinated; action potentials (nerve impulses)

Question 7

main receptive or main input region of a neuron

Answer 7

dendrite

Question 8

many organelles in the cell body extend into the dendrites, except ____

Answer 8

the golgi apparatus

Question 9

conducting region of a neuron; it can generate action potentials (nerve impulses) and transmit them; can be myelinated

Answer 9

axon (nerve fiber)

Question 10

a cellular process responsible for movement of mitochondria, lipids, synaptic vesicles, proteins, and other cell parts (i.e. organelles) to and from a neuron’s cell body, through the cytoplasm of its axon

Answer 10

axonal transport

Question 11

movement toward the synapse or down the axon toward the axon terminal (i.e. of a neurotransmitter) is _____

Answer 11

anterograde transport

Question 12

movement toward the cell body

Answer 12

retrograde transport

Question 13

types of neurons based on structure (number of processes connected to cell body)

Answer 13

1. multipolar - 3 or more processes
2. bipolar - 2 processes
3. unipolar - 1 process

Question 14

types of neurons based on function (impulse’s direction of travel relative to CNS)

Answer 14

1. sensory of afferent (toward CNS)
2. motor or efferent (away from CNS)
3. interneurons or associations neurons (found betw sensory and motor neurons)

Question 15

most abundant type of neuron, major neuron type in the CNS

Answer 15

multipolar

Question 16

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

Answer 16

bipolar

Question 17

found mainly in PNS; common only in DRG of the spinal cord and sensory ganglia of cranial nerves

Answer 17

unipolar neurons

Question 18

multipolar neurons can be ____ or _____

Answer 18

motor (efferent); interneurons (association) neurons that conduct impulses within the CNS

Question 19

unipolar neurons are ____ neurons that conduct impulses along ____ pathways to the CNS for interpretation; deal with ____ info from the skin or muscles

Answer 19

sensory; afferent; somatic afferent

Question 20

transmission of info from neuron to neuron or neuron to effector organ

Answer 20

synapse

Question 21

classification of synapses based on which neuronal components are involved

Answer 21

1. axodendritic - axon terminal and dendrite
2. axosomatic- axon terminal and cell body
3. axoaxonic synapse- between axons
4. dendrodendritic- between dendrites
5. dendrosomatic- between dendrite and cell body

Question 22

neuron carrying impulse/signal toward synapse

Answer 22

presynaptic neuron

Question 23

neuron carrying impulse/signal away from synapse

Answer 23

postsynaptic neuron (effector cell)

Question 24

2 types of synapses

Answer 24

electrical and chemical

Question 25

chemical synapses have a synaptic cleft of ____ nm

Answer 25

20-50

Question 26

in chemical synapses, depolarization causes ____ to open

Answer 26

voltage-gated Ca channels

Question 27

chemical synapse: Ca signals for release of nt (stored in synaptic vesicles) via ____ into the _____

Answer 27

exocytosis; synaptic cleft

Question 28

chemical synapse: NT diffuses across synaptic cleft and binds to NT receptors at _____; each receptor is part of a ____

Answer 28

postsynaptic membrane; ligand-gated channel

Question 29

chemical synapse: binding of the NT opens associated ligand-gated channels, allowing _____ to flow across ____

Answer 29

ions; post-synaptic membrane

Question 30

the flow of ions in a chemical synapse produces local changes in membrane potential called the _____, a type of ____ potential (depolarizing or hyperpolarizing)

Answer 30

postsynaptic potential; graded

Question 31

a typical chemical synapse contains a _____, a ____, and a _____

Answer 31

presynaptic knob (synaptic end bulb or presynaptic axon terminal); synaptic cleft; postsynaptic membrane

Question 32

examples of neurotransmitters in a chemical synapse

Answer 32

ACh, biogenic amines, amino acids, peptides, ATP, dissolved gases (nitric oxide, carbon monoxide)

Question 33

3 ways the nt can be removed from the postsynaptic receptor

Answer 33

1. degradation by enzymes 2. reuptake by astrocytes or presynaptic terminal 3. diffusion away from synapse

Question 34

types of neuroglia

Answer 34

astrocyte, microglial cell, ependymal cell, oligodendrocyte (all in CNS) schwann cells and satellite cells (in PNS)

Question 35

produce myelin sheaths in the CNS, providing electrical insulation to axons; the prominent neuroglia in white matter

Answer 35

oligodendrocytes

Question 36

the largest of the neuroglia; can be found in either white or gray matter- majority in gray matter

Answer 36

astrocytes

Question 37

astrocytes are connected to one another through ____

Answer 37

gap junctions

Question 38

astrocytes control the ionic environment around neurons by regulating ____ concentration

Answer 38

potassium

Question 39

astrocytes have ____ that contribute to the BBB

Answer 39

perivascular feet

Question 40

neuroglia cell that lines spaces in the brain and spinal cord (ventricles, central canal, etc.)

Answer 40

ependymal cells

Question 41

ependymal cells have ____ that extend into spaces with CSF; helps the CSF move and flow; help to make up the choroid plexus that produces CSF

Answer 41

cilia

Question 42

neuroglia that is less numerous than oligodendrocytes and astrocytes; have elongated nuclei

Answer 42

microglia

Question 43

microglia originate from ____ and enter CNS during development

Answer 43

blood monocytes (bone marrow)

Question 44

microglia are part of immune system- look like ____ when activated; proliferate and act as ____ cells

Answer 44

macrophages; antigen-presenting

Question 45

schwann cells also called _____

Answer 45

neurolemmocytes

Question 46

difference between oligiodendrocytes and schwann cells

Answer 46

one schwann cell produces one myelin sheath or internodal segment and one oligodendrocyte can produce many sheaths

Question 47

cells found in the PNS surrounding cell bodies in ganglia; have a supportive role, most likely having to do with metabolic exchange or structural support

Answer 47

satellite cells

Question 48

clusters of neuronal cell bodies in PNS/CNS

Answer 48

PNS: ganglion CNS: nucleus

Question 49

bundle of neuronal axons in PNS/CNS

Answer 49

PNS: nerve CNS: tract

Question 50

a nerve contains:

Answer 50

1. neuron processes (i.e. axons) 2. schwann cells 3. connective tissue 4. blood vessels 5. lymphatic vessels

Question 51

connective tissue coverings associated with nerves:

Answer 51

1. endoneurium 2. perineurium (forms fascicles) 3. epineurium

Question 52

nerves classified by what direction they are transmitting their impulses

Answer 52

1. sensory (afferent) 2. motor (efferent) 3. mixed- both sensory and motor fibers; most common

Question 53

nerves can also be classified as:

Answer 53

1. cranial- originate/arise at brain- 12 pairs | 2. spinal- originate/arise at spinal cord- 31 pairs

Question 54

schwann cells associated with unmyelinated axons for a ____ role for ____ support

Answer 54

supportive; structural

Question 55

function of myelin sheaths

Answer 55

1. protect and electrically insulate axons from other axons | 2. increase speed of nerve impulse transmission

Question 56

the nucleus, cytoplasm, and last layer of plasma membrane make up the _____ of the schwann cell

Answer 56

neurilemma

Question 57

rate of impulse propagation depends on:

Answer 57

1. axon diameter | 2. myelination

Question 58

the larger tha axon diameter, the ____

Answer 58

faster the action potential

Question 59

unmyelinated axons produce ____ conduction

Answer 59

continuous

Question 60

myelinated axons produce ____ conduction

Answer 60

saltatory