Chapter 9 Flashcards
Nervous System
The nervous system contains specialized, communicating nerve cells called ___________, and supporting cells called __________.
Neurons
Neuroglia
The Central Nervous System is made up of the ______________ & ___________.
Brain
Spinal Cord
The Peripheral Nervous System is made up of the __________ and __________ nerves.
Cranial
Spinal Nerves
Neuroglial cells fill spaces, support neurons, provide structural frameworks, produce myelin, and carry on phagocytosis. Four are found in the _____________ and one main type in the ____________.
___________ are small cells that phagocytize bacterial cells and cellular debris.
Microglia
_________ form myelin in the central nervous system.
Oligodendrocytes
__________ are near blood vessels and support structures, aid in metabolism, and respond to brain injury by filling in spaces.
Astrocytes
_________ cover choroid plexuses and form inner linings that enclose ventricles of the brain.
_________ cells are the myelin-producing neuroglia of the peripheral nervous system.
Schwann Cells
A neuron has a _________ with mitochondria, lysosomes, a Golgi apparatus, chromatophilic substance (Nissl bodies) containing rough endoplasmic reticulum, and neurofibrils
Cell Body (soma)
Nerve fibers contain a solitary out-going __________ and numerous _________, which bring in impulses from receptors.
Larger axons in the PNS are enclosed by ________ sheaths provided by __________ cells.
Myelin Sheaths
Schwann?
The outer layer of covering in myelinated peripheral neurons is called the _________.
Narrow gaps in the myelin sheath are called ___________ of ____________.
Nodes of Ranvier
__________ neurons have many dendrites and one axon arising from their cell bodies; most neurons with cell bodies in CNS (interneurons and motor neurons) are multipolar.
Multipolar
___________ neurons have 2 processes extending from the cell body, a dendrite and an axon; found in some of the special senses, such as the eyes, nose, and ears.
Bipolar
____________ neurons have only 1 process extending from the cell body; outside the cell body, it soon splits into 2 parts that function as 1 axon; the peripheral process has dendrites near a peripheral body part, and the central process runs into the CNS; the cell bodies are found in ganglia outside the CNS; these are sensory neurons.
Unipolar
_________ neurons (afferent neurons) conduct impulses from peripheral receptors to the CNS, and usually have a _______ structure, but may also have a _______ structure.
Sensory neurons
Unipolar Structure
Bipolar Structure
_____________ are multipolar neurons within the CNS that form links between other neurons.
Interneurons
________ neurons are multipolar neurons that conduct impulses from the CNS to effectors.
Motor (efferent)
The junction between two communicating neurons is called a _____________; there is a _________ _________ between them across which the impulse must be conveyed.
Synapse
Synaptic Cleft
_________ ________ it the process by which the impulse in the presynaptic neuron is transmitted across the synaptic cleft to the postsynaptic neuron.
Synaptic transmission
When an impulse reaches the synaptic knob of an axon, synaptic __________ release chemicals called __________ into the synaptic _________.
Synaptic Vesicles
Neurotransmitters
Synaptic Cleft
A cell membrane is usually polarized, due to an unequal distribution of positive and negative ___________ across the membrane; polarization is important to the conduction of nerve impulses.
Charges
The distribution of ions is determined by the membrane __________ that are selective for certain ions.
Potential
__________ ions pass through the membrane more readily than do ________ ions, making the former a major contributor to membrane polarization.
Due to active transport, the cell maintains a greater concentration of ___________ ions outside and a greater concentration of _____________ ions inside the membrane.
Sodium Ions
Potassium Ions
The inside of the membrane has excess ___________ charge, while the outside has more ___________ charge.
Negative
Positive
The difference in electrical charge between two regions is called a _________ _________.
Because neurons can respond to changes in their surroundings they are ________.
If the resting potential decreases, the membrane becomes ___________.
___________ potential changes are graded. This means the magnitude of change is proportional to the intensity of the stimulus.
What is the result of a neuron reaching its threshold potential? _______
During an action potential, the membrane of the neuron undergoes _________, followed by _________, followed by a brief _________, before returning to its resting potential.
___________ axons conduct impulses over their entire membrane surface.
Unmyelinated
____________ axons conduct impulses from node of Ranvier to node of Ranvier, a phenomenon called ____________ conduction. This conduction is many times faster .
Myelinated
Saltatory
The greater the diameter of an axon, the _________ the impulse.
Greater the speed of the impulse
A(n) ___________ ___________ is not graded, therefore it is an all-or-none response. A greater intensity of stimulation does not produce a stronger response; instead, it produces more __________ __________ per second.
Neurotransmitters that increase postsynaptic membrane permeability to sodium ions may trigger impulses and are thus _____________.
Excitatory
Other neurotransmitters may decrease membrane permeability to sodium ions, reducing the chance that it will reach threshold , and are thus ___________.
Inhibitory
When an action potential reaches the synaptic knob, ____________ ions rush inward, and in response, some synaptic vesicles fuse with the membrane and release their contents to the synaptic cleft.
Calcium
______________ in some synaptic clefts and on postsynaptic membranes rapidly decompose the neurotransmitters after their release. Destruction or removal of neurotransmitter prevents continuous stimulation of the postsynaptic neuron.
Enzymes
A particular neuron of a pool may receive excitatory or inhibitory stimulation; if the net effect is excitatory but ____________ the neuron becomes more excitable to incoming stimulation (a condition called facilitation).
Repeated
A single neuron within a pool may receive impulses from two or more fibers. This is called _________ , and makes it possible for the neuron to summate impulses from different sources.
Convergence
Impulses leaving a neuron in a pool may be passed to several output fibers. This is called __________ and serves to amplify an impulse.
Divergence
Nerves are bundles of ___________.
Fibers (axons)
Nerves that bring sensory information into the CNS are called ________ neurons.
Sensory Nerves
_________ nerves carry impulses from the CNS.
Motor Nerves
Nerves containing both sensory and motor fibers are called __________ nerves.
Mixed Nerves
A reflex arc includes a sensory ____________, a ___________neuron, one or more __________ that serve as a reflex center, a _______________ neuron whose axons pass out of the CNS, and a(n) ___________ that carries out the reflex response.
Sensory Receptor
Sensory Neuron
Interneurons
Motor Neuron
Effector
__________ are automatic, subconscious responses to stimuli that help maintain homeostasis.
Reflexes
The outermost layer is made up of tough dense connective tissue, contains many blood vessels, and is called the ______________.
Dura Mater
The sheath around the spinal cord is separated from the vertebrae by a/an ____________ space.
Epidural Space
The middle layer, the _____________, is thin and lacks blood vessels and looks like a spider web.
Arachnoid Mater
The innermost layer, the _____________, is thin and contains many blood vessels and nerves.
Pia Mater
Between the middle and the innermost layers is a _________ space containing ________ fluid.
Subarachnoid Space
Cerebrospinal Fluid (CSF)
Gray matter: Where is it located in the spinal cord? _______ Why does it appear gray? _______
Butterfly shaped core of the spinal cord
???
White matter: White matter, made up of bundles of ___________ nerve fibers (nerve tracts), surrounds a butterfly-shaped core of gray matter.
myelinated
Central canal: The central canal contains __________ fluid.
Cerebrospinal
Conducting nerve impulses: Tracts carrying sensory information are called _________ _________.
Spinothalamic Tracts
Those that conduct motor impulses from the brain are called _________ _________.
Descending Tracts
What are the four major divisions of the brain? _______
Cerebrum
Diencephalon
Cerebellum
Brainstem
The cerebrum is the largest portion of the brain. It is divided into two ______________
Cerebral Hemispheres
A broad, flat bundle of nerve fibers called the ___________ connects the two hemispheres.
Corpus Callosum
The surface of the brain is marked by ridges, called___________, shallow grooves, called ____________ and deep grooves called _________
Gyri
Sulci
Fissures
The lobes of the cerebral hemispheres are named according to the bones they underlie, in most cases. What are the names of the 5 lobes? _______
Parietal Lobe
Frontal Lobe
Occipital Lobe
Temporal Lobe
Insula
A thin layer of gray matter, the cerebral ___________, lies on the outside of the cerebrum and contains 75% of the cell bodies in the nervous system.
Cortex
Describe the Sensory Function
They interpret sensory input, producing feelings or sensations:
Describe the Motor Function
Movement
Describe the Association Function
Association areas of the brain analyze and interpret sensory impulses, and function in reasoning, judgment, emotions, verbalizing ideas, and storing memory:
Which hemisphere is dominant in 90% of the population? _________________________________
Left
What does the non-dominant hemisphere specialize in? ___________________________________
Nonverbal functions, such as body orientation in space, and controls emotions and intuitive thinking.
What are the main functions of the basal nuclei (ganglia)? ___________________________________
Relay motor impulses from the cerebrum, and help control motor activities by interacting with the motor cortex, thalamus, and cerebellum.
Help facilitate voluntary movement.
The ventricles are a series of __________ within the cerebral hemispheres and brain stem.
Connected Cavatites
How many ventricles are there? _______
Four
The ventricles are continuous with the central canal of the spinal cord, and are filled with __________ fluid.
Cerebrospinal
____________ plexuses, specialized capillaries from the pia mater, secrete the CSF. What is the function of this fluid? ___________________
Choroid
CSF has nutritive as well as protective (cushioning) functions.
The ___________ functions in sorting and directing sensory information arriving from other parts of the nervous system, performing the services of both messenger and editor. It acts like an executive secretary for the cerebrum.
Thalamus
The ___________ maintains homeostasis by regulating a wide variety of visceral activities and by linking the endocrine system with the nervous system. List the other activities it regulates. ______________
Hypothalamus
* Regulates heart rate and arterial blood pressure.
* Regulates body temperature, water and electrolyte balance, hunger and body weight.
* Controls movements and secretions of the digestive tract.
* Helps to regulate sleep and wakefulness.
* Stimulates the posterior pituitary gland to secrete stored hormones.
* Produces hormones that cause the anterior pituitary gland to secrete its hormones.
Bundles of myelinated axons form nervous system tissue called
White Matter
Unmyelinated axons, dendrites, neuron cell bodies, and synapses are found within nervous system tissue called
Gray Matter
An action potential results from the opening of
________ _______.
These channels open when tr membrane potential reaches a level called ______ ______.
Sodium Channels
Threshold Potential
This local current stimulates the ________ ________ to reach its threshold.
Adjacent Membrane
When the membrane potential reaches threshold, voltage-gated channels open, triggering an ________ ________ at the location
Action Potential
This cycle continues, resulting in action potentials traveling down the axon. This is also called ________ conduction.
Impulse
What is the name of the specialized capillaries that secrete cerebrospinal fluid?
Choroid Plexuses
Which function carries out effect
Motor Function
Which function decides response
Integrative Function
Which function detects stimulus / Informs CNS
Sensory Function
In the majority of right-handed people, the left hemisphere is dominant for what function?
Language
What connective tissue layer surrounds an axon?
Endoneurium
Place the steps of the patellar reflex in the correct order.
1 - Stimulus
2 - Receptors
3 - Spinal Cord
4 - Motor Neuron
What is the main functional unit of the nervous system?
Neuron
The ________ is considered the autonomic control center of the body due to its regulation of hormonal secretion and heart rate.
hypothalamus
The majority of all afferent pathways pass through and synapse with neurons of the ________
thalamus
Comprised of parts of the cerebral cortex, diencephalon, and other deep nuclei, the ________ represents the area of emotional control.
Limbic System
Composed of three parts, the ________ provides basic life support functions including the cardiovascular and respiratory systems
Brainstem
The ________ ________ is the alert system of the body because of the tracts that provide communication between lower and higher brain regions.
Reticular Formation
The largest portion of the brain is the
Cerebrum
Four types of tissues combine to form all the ________ in the human body.
Organs
The tissue type called ________ allows you to sense and respond to the world you live in.
Nervous Tissue
Nervous tissue cells are specialized for receiving and sending information. The cells responsible for transmitting the information are called
Neurons
Also found in the nervous tissue are support cells which provide insulation and nutrients. These cells are known as the ________ cells.
Neuroglial
What type of electrical signal is an all-or-none response?
Action Potential
The limbic system interprets sensory impulses from the receptors associated with which sense?
Smell
Which Nerve? Sense of vision
Optic Nerve
Which Nerve? Controls muscles of facial expression
Facial
Which Nerve? Sense of equilibrium
Vestibulocohlear
Which Nerve? Cutaneous sensation from the face
Trigeminal
Which Nerve? Controls heart rate and glands in abdomen
Vagus
What is the name of the tapering, inferior end of the spinal cord?
Conus medullaris
The disease called multiple sclerosis involves an immune response against myelin of the central nervous system, causing scar formation (sclerosis) within the neural tissue. How would this affect nerve impulse conduction?
Impulses are blocked or interrupted.
What occurs during depolarization of an axon?
Sodium channels open, and sodium diffuses into the cell.
Which of the following axons would have the fastest impulse conduction?
Large-diameter myelinated axon
At a synapse, the neuron that releases the neurotransmitter (sends the signal) is the ________ ________ and the neuron that responds to the neurotransmitter (receives the signal) is the ________ ________
presynaptic neuron; postsynaptic neuron
The effectors of the ________ nervous system are skeletal muscles
Somatic
The effectors of the ________ nervous system include cardiac muscle, smooth muscle, and glands.
Autonomic
What type of functional area of the cerebral cortex would be responsible for sending impulses that control skeletal muscles?
Motor Area
What would happen if there were no Schwann cells?
Muscles would not be able to contract, and the body would be paralyzed.
