Nervous System Assignment
Section 8.1
1. The 3 specific functions of the nervous system are ______sensory input
_____motor output __
___, _____integration
, and
.
2. The 2 major divisions of the nervous system are the ___central nervous system___ which consists of the
____brain_______and __ spinal cord ___, and the ___peripheral nervous system______ which consists of the
___cranial_ nerves____and ______spinal nerves______.
3. Name the 2 types of cells found in nervous tissue and give their functions.
Neurons- transmit nerve impulses
Neuroglia – support and nourish neurons
4. The 3 major parts of a neuron are the _______cell body________, ______dendrites______ and
_______axon________.
5. What is a nerve? a bundle of axons in the PNS
6. What is a tract? a bundle of axons in the CNS
7. How do nerves and tracts differ from each other?
Location
8. Label the following diagram of a myelinated neuron.
Axon
terminals
Nucleus
Node of
Ranvier
Cell body
Myelin sheath
Dendrites
Axon
9. What are the three types of neurons and what are their functions?
Sensory – carry sensory information from receptors to CNS
Motor – carry impulses from CNS to muscles, glands
Interneurons (association neurons) – form pathways in CNS
10. What are neurotransmitters?
Chemical messengers used in the nervous system; produced and secreted by neurons
11. A nerve signal is known as an ____action potential__________________.
12. The cell membrane has a ______negative
________ charge on the inside and a
_______positive_______________ charge outside. The potential energy that exists across a cell membrane is called
____resting membrane potential______.
13. In which part of a neuron does an action potential occur? the axon
14. At the beginning of an action potential, channels for sodium open. This allows sodium to move into / out of the cell.
The movement of sodium causes the inside of the cell to become ____positive______ compared with the outside. This
change in membrane potential is called a ________depolarization_________________. The next thing that happens is
that the sodium channels close, and potassium channels open. Movement of sodium ions stops, but now potassium
ions start to move into / out of the cell. The inside of the cell becomes more _____negative___________ compared to
the outside. This change in membrane potential is called _______repolarization________________.
Conduction of an action potential either occurs or does not occur, therefore, it is described as being an
____________all-or-none________________________ event. In an unmyelinated axon, an action potential stimulates
the next part of the membrane to have an action potential, and so on until the end of the axon is reached. Conduction is
faster / slower in a myelinated axon because the action potential jumps from one ________node of Ranvier__________
to the next. This is known as ________saltatory__________ conduction. Action potentials always travel from the cell
body to the axon terminal because of the _________refractory____________ period.
The axon can branch into many endings that are known as ________axon terminals___________________________.
The endings come close to other neurons at an area called a ________synapse___________. The two neurons do not
touch each other, but instead are separated by a gap called the _________synaptic cleft__________________.
In the axon terminal, there are vesicles filled with chemical messengers called _______neurotransmitters_________.
When an action potential reaches the axon terminal, channels for _____calcium_____________ open, and the ions
move into / out of the axon. This causes the neurotransmitters to leave the cell by the process
of______exocytosis_________________. The neurotransmitters diffuse across the cleft and bind to
_________receptors________ on the membrane of the ________postsynaptic_____________ neuron.
15. Label the following diagram of a synapse.
presynaptic neuron
axon
postsynaptic neuron
axon terminal
vesicles
presynaptic
neuron
axon terminal
neurotransmitter
vesicle
synaptic cleft
synaptic cleft
axon
postsynaptic neuron
neurotransmitter
Section 8.2
1. Gray matter is gray because it consists of ___cell bodies and unmyelinated nerve fibers____________________.
White matter is white because it consists of ____myelinated axons________________________________________.
2. The protective coverings of the brain and spinal cord are called _________meninges_________. The outermost layer
is called the _____dura mater__________. The middle layer is called the ____arachnoid mater_______________, and
the deepest layer is the _____pia mater_______. The subdural space is located between the dura and arachnoid, and it
is normally not filled with anything. The ____subarachnoid______ space is found between the arachnoid and pia, and it
is normally filled with _________ cerebrospinal fluid ________________________.
3. The spinal cord begins at the base of the brain and travels through the large opening called the _____formen
magnum_________ ___________________________ which is found in the base of the skull. The spinal cord then
travels through the canal in the ____________________________.
4. Label the following cross section of the spinal cord.
5. The four major regions of the brain are the _____cerebrum____________, _______diencephalon_________,
______brainstem_______________, and ___________cerebellum__________________. There are 4 hollow areas in the
brain called ______ventricles________________. These areas are filled with and are the site of production of
________cerebrospinal fluid_____. The 2 lateral ventricles are located in the _____cerebrum_______, while the 3rd
ventricle is associated with the _________diencephalon_____________, and the 4th ventricle is associated with the
___________brainstem____________.
The cerebrum is divided into left and right ___________hemispheres______________; the left and right side are
connected by a “bridge” of white matter called the _________corpus callosum____________. The cerebrum has 5
lobes, the ______temporal_____________, __________parietal____________, _______frontal________, and
_______occipital____________ lobes, and the ____________insula__________.
6. Label the diagram of the brain. Is this the right or left hemisphere? ___left____ Color the frontal lobe green, parietal
lobe blue, occipital lobe yellow, and temporal lobe red. Draw an eye on the area where visual information is processed.
Draw an ear on the area where the auditory information is processed. Draw a mouth where taste information is
processed.
Central sulcus
Central sulcus
Temporal lobe
Parietal
Occipital lobe
Frontal
lobe
Frontal lobe
Temporal
Occipital
Parietal lobe
7. Is the primary sensory area anterior or posterior to the central sulcus? ___posterior__________________________
What about the primary motor area? ____anterior______________________
8. The part of the diencephalon that regulates hunger thirst, sleep, temperature and water balance is the
_____hypothalamus_______. The part that acts as a relay station for incoming sensory information is the
______thalamus_______. The part of the brain that ensures smooth, coordinated muscle movement is the
____cerebellum______. It is divided into 2 portions called _____hemispheres__________________. The brain stem
consists of three parts, the _______pons_____________, _______midbrain_____________, and _____medulla
oblongata________.
Section 8.3
1. Ganglia are collections of _______cell bodies___, while nerves are collections of ______axons_________. The 2
major division of the PNS are the ____afferent_______ (sensory) and ______efferent_______(motor) systems. The
sensory system is divided into ______somatic________ and ________visceral_____ parts. The motor system is divided
into _____somatic___________ and ______autonomic______ parts. _______Cranial______nerves are attached to the
brain, while ____spinal______ nerves are attached to the spinal cord.
2. Label the following diagram of a nerve.
3. There are __12___ pairs of cranial nerves and ____31___ pairs of spinal nerves. Automatic, preprogrammed
responses to changes that occur inside of outside of the body are called _______reflexes_____________. They are
essential to maintaining ______homeostasis______. Reflexes that involve the brain are called ___cranial
reflexes_______ while reflexes that involve only the spinal cord are called ___spinal reflexes_______.
4. The autonomic nervous system is made up of two divisions, the ___sympathetic______ , which is the “fight-or-flight
division” and the ____parasympathetic____, which is the “rest and digest” division. These two divisions of the ANS have
the following features in common:
1.___function automatically___________________________________________________________________
2.___innervate all internal organs______________________________________________________________
3. ___use two motor neurons and one ganglion___________________________________________________
5. Label the following diagrams. Decide which is the sympathetic system and which is the parasympathetic.
6. Fill in the following table.
Parasympathetic Effect
Increased heart rate
Decreased heart rate
Sympathetic Effect
X
X
Increased size of bronchi
X
Increased supply of glucose/O2
X
Increased activity of digestive tract
X
Decreased strength of heart contraction
X
Decreased activity of bladder
X