Central Nervous System -Correct Answer "general" of the body; integration of sensory input and origin of motor responses
• brain
• spinal cord
Peripheral Nervous System -Correct Answer body; sensory input and motor output
• nerves
• sensory receptors
• motor neurons
sensory rec...
BIOL 252 Exam 1 Study Questions with Correct
Answers Top Graded 2024
Central Nervous System -Correct Answer ✔"general" of the body; integration of sensory
input and origin of motor responses
• brain
• spinal cord
Peripheral Nervous System -Correct Answer ✔body; sensory input and motor output
• nerves
• sensory receptors
• motor neurons
differentiated based on location
• somatic
• visceral
somatic sensory receptors -Correct Answer ✔receptors and neurons that are located in
the skin, skeletal muscle, joints
visceral sensory receptors -Correct Answer ✔receptors and neurons that are located in
internal organs
motor neurons -Correct Answer ✔Efferent neurons → Exit/Effect signals
- differentiated not based on location, but rather on the target organs
• somatic nervous system
• autonomic nervous system
somatic nervous system -Correct Answer ✔system of neurons that enervate skeletal
muscles
autonomic nervous system -Correct Answer ✔system of neurons that enervate smooth
and cardiac muscles; glands
Santiago Ramon y Cajal -Correct Answer ✔discovered the neuron using a modification
of Golgi's staining method that allowed Cajal to see the minutia of neurons and draw
their anatomy
basic structure of a neuron -Correct Answer ✔- soma
- dendrites
- axon hillock
soma -Correct Answer ✔cell body
- can receive inputs
dendrites -Correct Answer ✔branching from the cell body of the neuron which have the
major function of receiving inputs
*D*endrite → *D*ownload
axon hillock -Correct Answer ✔hump on the soma of a neuron from which the axon of
the neuron extends
axon -Correct Answer ✔long singular stalk extending from the soma of the neuron
which creates action potentials and sends inputs to other neurons
*A*xon → *A*way
myelin -Correct Answer ✔insulation present on some axons of the nervous system (not
present on all axons); whitish fatty segmented sheath around mot long (NOT ALL)
axons that increase the speed of nerve impulse transmission
- cell has concentric layers of membrane that make up the myelin sheath
- ONLY on axons (NOT dendrites, soma, etc.) but not all axons
- made from Oligodendrocytes (CNS) and Schwann cells (PNS)
- rather than one long piece of insulation, is multiple small pieces of insulation
-- nodes of ranvier
nodes of ranvier -Correct Answer ✔areas of the axon that is not covered in myelin,
occurs between cells of myelin
terminal arbor -Correct Answer ✔fine branching at the end of the axon
terminal buttons -Correct Answer ✔regions at the end of terminal arbor branches that
release neurotransmitters into the synapse
astrocytes -Correct Answer ✔• support and brace neurons
• control the chemical environment
• important physiological roles
--- can secrete/absorb different molecules (i.e., ions)
• most abundant cells in the brain (more than neurons)
Oligodendrocytes -Correct Answer ✔insulators of the thick neurons of the CNS
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,BIOL 252 Exam 1
• one cell creates several units of myelin sheath and can insulate many different axons
ependymal cells -Correct Answer ✔circulate the CSF
satellite cells -Correct Answer ✔glial cells that surround somas of neurons in the
ganglia; provide electrical insulation and regulate chemical environment of neurons
microglia -Correct Answer ✔immune cells of the CNS
Blood Brain Barrier (BBB) -Correct Answer ✔- astrocytes are important in telling the
capillaries of the brain to form tight functions/inducing formation of BBB BUT are not
part of the BBB themselves
- tight junctions between endothelial cells of the capillaries in the brain form the BBB
• BBB is between the extracellular fluid (ECF) and the brain
ciliated epithelial cells -Correct Answer ✔- lining the central cavities of the brain and
spinal column
- forming a permeable barrier between the CSF and nervous tissue
cilia -Correct Answer ✔made of tubules; can be static or dynamic (beating)
ependymal cilia are... -Correct Answer ✔dynamic (beating) which helps to
move/circulate the CSF
• without movement of CSF, there would be an accumulation which would lead to an
over-sized brain (hydrocephalus)
• ciliated epithelial cells also help create CSF
Hydrocephalus -Correct Answer ✔excess cerebrospinal fluid
• can be due to many things → lack of cilia, lack of drainage for CSF, etc.
• treated by inserting a shunt and tubing leading to a cavity in the body (i.e., stomach)
where the CSF can drain and be flushed
leak/leakage (passive) channels -Correct Answer ✔• based on three dimensional
configuration (3DC)
• these channels are ion specific based on the shape (3DC) of the ions
• will only have inward channels and not outward channels
• movement occurs based on concentration gradient so we only need one type of
channel and the direction of flow will be determined by the concentration gradient
• ions carry charge to in addition to concentration gradient there is also electrochemical
gradient which will determine ion flow
what will happen when there is more K+ inside than outside the cell? -Correct Answer
✔K+ will move outside the cell down it's diffusion gradient
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what will happen when there is more K+ and negatively charged proteins inside,
only/less K+ outside the cell? -Correct Answer ✔• K+ leaves the cell via K+ leak
channels due to the chemical gradient
• negatively charged proteins cannot leave the cell
• as K+ is leaving an electrical gradient starts to pick up, driving K+ back in
• at some point an equilibrium is reached via a combination of electrical and chemical
gradient
• with regards to K+ the electrical gradient counteracts the chemical gradient
membrane permeability to K+ vs Na+ -Correct Answer ✔membranes are much more
permeable to K+ than to Na+ so sodium will flow but has a much lower impact on the
membrane potential
• K+ is found in higher concentrations inside the cell
-- membrane easily permeable to K+
• Na+ is found in higher concentrations outside the cell
-- membrane less permeable to Na+
resting membrane potential is mainly dependent on... -Correct Answer ✔the K+
electrochemical gradient it is negative (-70 mV)
BUT what creates the chemical gradient in the first place? -Correct Answer ✔the Na+-
K+ pump restores the chemical gradients (works against the gradient) and therefore
maintains the resting membrane potential
the Na+-K+ pump requires... -Correct Answer ✔energy (ATP) to bring back the K+ that
has just left and kick out the Na+ that has just entered
• use 1 ATP (convert to ADP and phosphate)
• returns 2 K+
• expels 3 Na+
all this is achieved by a movement of only a fraction of the ions involved (0.0006% of
the K+ ions actually move)
if the pumps did not work... -Correct Answer ✔action potentials would be impossible
because there would be no chemical gradient → all functioning would be impossible
Summary of membrane info -Correct Answer ✔- the membrane is much more
permeable to K+ than to Na+
- the electrical gradient counteracts the chemical gradient, and the ions reach
equilibrium
- the K+/Na+ pump maintains the chemical gradient and is essential to create and
maintain a negative resting membrane potential
two broad classes of membrane proteins -Correct Answer ✔• integral proteins
• peripheral proteins
BIOL 252 Exam 1
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