BHSC 1200 MIDTERM 2 QUESTIONS AND ANSWERS
organization of nervous system - Answers :1) central nervous system = brain and spinal
cord
-processes many different kinds of incoming sensory information
-source of thoughts, emotions and memories
-produces signals causing muscles to contracts and glands to secrete
2) peripheral nervous system = consists of all nervous tissue outside the CNS
-further divided into sensory (afferent) division [provides information about somatic
senses] and motor (efferent) division [conveys output from CNS to effectors]
-efferent division is further divided: somatic nervous system (conveys output from CNS
to skeletal muscle) and autonomic nervous system (conveys output from CNS to
smooth muscle, cardiac muscle, and glands)
-autonomic nervous system is further divided: sympathetic nervous system and
parasympathetic nervous system (usually have opposing actions)
functions of nervous system - Answers :-sensory function: sensory receptors detect
internal stimuli; sensory information is carried to brain and spinal cord
-integrative function: nervous system processes sensory information by analyzing it and
making decisions
-motor function: nervous system activates effectors causing muscles to contract and
glands to secrete
parts of a neuron - Answers :-cell body: contains a nucleus surrounded by cytoplasm
which includes organelles
-dendrite: receiving or input portions
-axon: long, thin, cylindrical projection; propagates nerve impulses toward another
neuron
-axon hillock: cone shaped elevation; joins axon to cell body
-trigger zone: junction of axon hillock and initial segment; generates nerve impulses
which travel along the axon to their destination
-axon terminal: numerous fine processes originating from the axon
-synaptic bulb: bulb-shaped swellings of the tips of axon terminals; contain synaptic
vesicles that store neurotransmitters
structural classification of neurons - Answers :-multipolar: have several dendrites and
one axon; brain and spinal cord
-bipolar: one main dendrite and one axon; retina of eye, inner ear, olfactory area of
brain
-unipolar: have dendrites and one axon that are fused together to form a continuous
process that emerges from the cell body; function as sensory receptors
functional classification of neurons - Answers :-sensory: afferent neurons; either contain
sensory receptors at their distal ends or are located just after sensory receptors that are
separate cells; forms action potentials; most are unipolar
,-motor: efferent neurons; convey action potentials away from CNS to effectors; most are
multipolar
-interneurons: association neurons; mainly located within CNS between sensory and
motor neurons; process incoming sensory information and elicit motor response by
activating motor neurons; most are multipolar
characteristics and function of astrocytes - Answers :-most abundant, versatile, and
highly branched glial cells
-cling to neurons, synaptic endings, and capillaries
-functions: support and brace neurons; play role in exchanges between capillaries and
neurons through BBB; guide migration of young neurons; respond to nerve impulses
and neurotransmitters; influence neuronal functioning
characteristics and function of microglia - Answers :-small, ovoid cells with thorny
processes that touch and monitor neurons
-migrate toward injured neurons
-can transform to phagocytize microorganisms and neuronal debris
characteristics and function of ependymal cells - Answers :-range in shape from
squamous to columnar
-may be ciliated (cilia beat to circulate CSF)
-line the central cavities of the brain and spinal column
characteristics and function of oligodendrocytes - Answers :-branched cells
-processes wrap CNS nerve fibres, forming insulating myelin sheaths thicker nerve
fibres
myelin sheath - Answers :lipid protein material that acts as an insulator of nerve cells
and speeds up nerve conduction
structure and function of satellite cells - Answers :-cover surface of nerve cell bodies
-regulation of extracellular environment of PNS neurons
characteristics and function of Schwann cells - Answers :-wrap around axon in jelly roll
fashion
-one cell forms one segment of myelin sheath
myelination of neurons in CNS vs myelination of neurons in PNS - Answers :CNS: an
oligodendrocyte puts forth about 15 broad, flat processes that spiral around CNS axons,
forming myelin sheath
PNS: a Schwann cell spirals around an axon many times, forming myelin sheath. The
outer nucleated cytoplasmic layer of the Schwann cell is the neurolemma, found only in
PNS
, composition of white and gray matter - Answers :-white matter: regions of the brain and
spinal cord with dense collections of myelinated fibres
-gray matter: mostly neuron cell bodies and nonmyelinated fibers
organization of white and gray matter in brain and spinal cord - Answers :brain: white
matter = deep; gray matter = superficial
spinal cord: white matter = superficial; gray matter = deep
resting membrane potential - Answers :-charge of plasma membrane at rest; potential
difference across membrane of resting cell
-approximately -70mV in neurons (cytoplasmic side of membrane negatively charged
relative to outside)
-membrane termed polarized
-generated by: differences in ionic makeup of ICF and ECF; differential permeability of
the plasma membrane
discuss the role of ion channels in establishing the resting membrane potential -
Answers :-leak channels: gated channels that randomly open and close; found in nearly
all cells
-ligand-gated channels: gated channels that open in response to binding of ligand
(chemical) stimulus; found in dendrites of some sensory neurons and dendrites and cell
bodies of interneurons and motor neurons
-mechanically-gated channels: gated channels that open in response to mechanical
stimulus (i.e., touch, pressure, vibration, or tissue stretching); found in dendrites of
some sensory neurons
-voltage-gated channels: gated channels that open in response to voltage stimulus
(change in membrane potential); found in axons of all types of neurons
discuss the role of intracellular proteins in establishing the resting membrane potential -
Answers :-ECF is rich in Na+ and Cl-; ICF is rich in K+
-plasma membrane has more K+ leak channels than Na+ leak channels so the inside of
membrane becomes increasingly negative as more K+ leave the cell than Na+ enter
-this is why the resting membrane potential is negative
discuss the role of the Na/K pump in establishing the resting membrane potential -
Answers :-stabilizes resting membrane potential
-maintains concentration gradient for Na+ and K+
-3 Na+ pumped out of cell; 2 K+ pumped in
graded potential vs action potential - Answers :-graded potential: small deviation from
the resting membrane potential that makes the membrane either more polarized or less
organization of nervous system - Answers :1) central nervous system = brain and spinal
cord
-processes many different kinds of incoming sensory information
-source of thoughts, emotions and memories
-produces signals causing muscles to contracts and glands to secrete
2) peripheral nervous system = consists of all nervous tissue outside the CNS
-further divided into sensory (afferent) division [provides information about somatic
senses] and motor (efferent) division [conveys output from CNS to effectors]
-efferent division is further divided: somatic nervous system (conveys output from CNS
to skeletal muscle) and autonomic nervous system (conveys output from CNS to
smooth muscle, cardiac muscle, and glands)
-autonomic nervous system is further divided: sympathetic nervous system and
parasympathetic nervous system (usually have opposing actions)
functions of nervous system - Answers :-sensory function: sensory receptors detect
internal stimuli; sensory information is carried to brain and spinal cord
-integrative function: nervous system processes sensory information by analyzing it and
making decisions
-motor function: nervous system activates effectors causing muscles to contract and
glands to secrete
parts of a neuron - Answers :-cell body: contains a nucleus surrounded by cytoplasm
which includes organelles
-dendrite: receiving or input portions
-axon: long, thin, cylindrical projection; propagates nerve impulses toward another
neuron
-axon hillock: cone shaped elevation; joins axon to cell body
-trigger zone: junction of axon hillock and initial segment; generates nerve impulses
which travel along the axon to their destination
-axon terminal: numerous fine processes originating from the axon
-synaptic bulb: bulb-shaped swellings of the tips of axon terminals; contain synaptic
vesicles that store neurotransmitters
structural classification of neurons - Answers :-multipolar: have several dendrites and
one axon; brain and spinal cord
-bipolar: one main dendrite and one axon; retina of eye, inner ear, olfactory area of
brain
-unipolar: have dendrites and one axon that are fused together to form a continuous
process that emerges from the cell body; function as sensory receptors
functional classification of neurons - Answers :-sensory: afferent neurons; either contain
sensory receptors at their distal ends or are located just after sensory receptors that are
separate cells; forms action potentials; most are unipolar
,-motor: efferent neurons; convey action potentials away from CNS to effectors; most are
multipolar
-interneurons: association neurons; mainly located within CNS between sensory and
motor neurons; process incoming sensory information and elicit motor response by
activating motor neurons; most are multipolar
characteristics and function of astrocytes - Answers :-most abundant, versatile, and
highly branched glial cells
-cling to neurons, synaptic endings, and capillaries
-functions: support and brace neurons; play role in exchanges between capillaries and
neurons through BBB; guide migration of young neurons; respond to nerve impulses
and neurotransmitters; influence neuronal functioning
characteristics and function of microglia - Answers :-small, ovoid cells with thorny
processes that touch and monitor neurons
-migrate toward injured neurons
-can transform to phagocytize microorganisms and neuronal debris
characteristics and function of ependymal cells - Answers :-range in shape from
squamous to columnar
-may be ciliated (cilia beat to circulate CSF)
-line the central cavities of the brain and spinal column
characteristics and function of oligodendrocytes - Answers :-branched cells
-processes wrap CNS nerve fibres, forming insulating myelin sheaths thicker nerve
fibres
myelin sheath - Answers :lipid protein material that acts as an insulator of nerve cells
and speeds up nerve conduction
structure and function of satellite cells - Answers :-cover surface of nerve cell bodies
-regulation of extracellular environment of PNS neurons
characteristics and function of Schwann cells - Answers :-wrap around axon in jelly roll
fashion
-one cell forms one segment of myelin sheath
myelination of neurons in CNS vs myelination of neurons in PNS - Answers :CNS: an
oligodendrocyte puts forth about 15 broad, flat processes that spiral around CNS axons,
forming myelin sheath
PNS: a Schwann cell spirals around an axon many times, forming myelin sheath. The
outer nucleated cytoplasmic layer of the Schwann cell is the neurolemma, found only in
PNS
, composition of white and gray matter - Answers :-white matter: regions of the brain and
spinal cord with dense collections of myelinated fibres
-gray matter: mostly neuron cell bodies and nonmyelinated fibers
organization of white and gray matter in brain and spinal cord - Answers :brain: white
matter = deep; gray matter = superficial
spinal cord: white matter = superficial; gray matter = deep
resting membrane potential - Answers :-charge of plasma membrane at rest; potential
difference across membrane of resting cell
-approximately -70mV in neurons (cytoplasmic side of membrane negatively charged
relative to outside)
-membrane termed polarized
-generated by: differences in ionic makeup of ICF and ECF; differential permeability of
the plasma membrane
discuss the role of ion channels in establishing the resting membrane potential -
Answers :-leak channels: gated channels that randomly open and close; found in nearly
all cells
-ligand-gated channels: gated channels that open in response to binding of ligand
(chemical) stimulus; found in dendrites of some sensory neurons and dendrites and cell
bodies of interneurons and motor neurons
-mechanically-gated channels: gated channels that open in response to mechanical
stimulus (i.e., touch, pressure, vibration, or tissue stretching); found in dendrites of
some sensory neurons
-voltage-gated channels: gated channels that open in response to voltage stimulus
(change in membrane potential); found in axons of all types of neurons
discuss the role of intracellular proteins in establishing the resting membrane potential -
Answers :-ECF is rich in Na+ and Cl-; ICF is rich in K+
-plasma membrane has more K+ leak channels than Na+ leak channels so the inside of
membrane becomes increasingly negative as more K+ leave the cell than Na+ enter
-this is why the resting membrane potential is negative
discuss the role of the Na/K pump in establishing the resting membrane potential -
Answers :-stabilizes resting membrane potential
-maintains concentration gradient for Na+ and K+
-3 Na+ pumped out of cell; 2 K+ pumped in
graded potential vs action potential - Answers :-graded potential: small deviation from
the resting membrane potential that makes the membrane either more polarized or less
