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Introduction
A) The __ is composed of __ and __.
1) What do neurons do?
2) __ are made up of bundles of nerve fibers.
3) __ carry out a variety of functions to __ and __ components of the nervous system
- nervous system, neurons, neuroglia
- 1) transmit nerve impulses along nerve fibers to other neurons
- 2) Nerves
- 3) Neuroglia, aid, protect
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B. Organs of the nervous system can be divided into the __, and the __.
- What are each made up of?
C. The nervous system provides __, __ and __ functions to the body.
- CNS (made of the brain and spinal cord)
- PNS (made up of peripheral nerves that connect the CNS to the rest of the body)
- C. sensory, integrative, motor
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General Functions of the NS
A. __ at the ends of __ gather information adn convert it into __.
B. When __ are integrated in the brain as __, this is the __ of the NS.
C. __ or __ decisions follow, leading to __ via __.
- A. Sensory receptors, peripheral nerves, nerve impulses
- B. sensory impulses, perceptions, integrative funciton
- C. Conscious, subconscious, motor functions, effectors (muscles, glands)
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Neuron Structure
A. What does a neuron have.
B. What do nerve fibers have?
1) Branching __ carry impulses from other neurons (or from receptors) toward the __.
2) The __ transmits thee impulse away from the __ of the __ and may give off side branches.
3) Larger __ are enclosed by __ provided by __ and are __.
a) The outer layer of __ is surrounded by a __ made up of the __ and __ of the __.
b) Narrow gaps in the __ between __ are called __.
4) The smallest axons lack a __ and are __.
5) __ in the CNS is due to __ in this area.
6) __ in the CNS appears __.
- A. cell body with mitochondria, a Golgi apparatus, lysosomes, Nissl bodies containing rough endoplasmic reticulum, and neurofibrils
- B. include a solitary axon and numerous dendrites
- 1) dendrites, cell body
- 2) Axon, axon hillock, cell body
- 3) axons, sheaths of myelin, Schwann cells, myelinated fibers
- a) myelin, neurilemma (neurilemmal sheath), cytoplasm, nuclei, Schwann cell
- b) myelin sheath, Schwann cells, nodes of Ranvier
- 4) myelin sheath, unmyelinated fibers
- 5) white matter, myelin sheaths
- 6) unmyelinated nerve tissue, gray
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Types of Neurons and Neuroglial Cells
A. Neurons can be grouped in two ways: __ and __.
- 1) on the basis of structural differences (bipolar, unipolar, and multipolar neurons)
- 2) and by functional differences (sensory neurons, interneurons, and motor neurons)
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Nerve Impulse
A. A __ is conducted as __ is reached at the __ and spreads by a local current flowing down the fiber, and adjacent areas of the membrane reach __.
B. __
1) __ conduct impulses over their entire membrane
2) __ conduct impulses from __ to __, a phenomenon called __.
3) __ is many times faster than __ on __.
C. __
1) If a nerve fiber responds at all to a stimulus, it responds __ by conducting an __ (__).
- A. nerve impulse/ action potential/ trigger zone/ action potential
- B. Impulse Conduction
- 1) Unmyelinated fibers
- 2) Myelinated fibers/ node of Ranvier to node of Ranvier/ saltatory conduction
- 3) Saltatory conduction/ conduction/ unmyelinated neurons
- C. All-or-None Response
- 1) completely/ impulse/ (all-or-none response)
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The Synapse
A. The junction between two communicating neurons is called a __; there exists a __ between them across which the impulse must be conveyed.
B. __
1) The process by which the impulse in the __ is transmitted across the __ to the __ is caled __.
2) When an impulse reaches the __ of an axon, __ release __ into the __.
3) The __ reacts with specific receptors on the __.
C. __
1) __ that increase __ to __ may trigger impulses and are thus __.
2) Other __ may decrease __ to __, reducing the chance that it will reach __, and are thus __.
- A) synapse; synaptic cleft
- B) Synaptic Transmission
- 1) presynaptic neuron; synaptic cleft; postsynaptic neuron; synaptic transmission
- 2) synaptic knobs; synaptic vesicles; neurotransmitters; synaptic cleft
- 3) neurotransmitter; postsynaptic membrane
- C) Excitatory and Inhibitory Actions
- 1) neurotransmitters; postsynaptic membrane permeability; sodium ions; excitatory
- 2) neurotransmitters; membrane permeability; sodium ions; threshold; inhibitory
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Types of Nerves
A) A __ is a bundle of nerve fibers held together by layers of connective tissue.
B) __ cna be__, __, or __, carrying both __ and __ fibers.
- A) nerve
- B) nerves, sensory, motor, mixed, sensory, motor
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Nerve Pathways
A. The routes nerve impulses travel are called __, the simplest of which is a __.
B. __
1) A __ includes a __, __, __, __, and __.
C. __
1) __ are automatic, subconscious responses to __ that help maintain __ and carry out automatic responses (__).
2) The __ is an example of a __.
3) The __ involves __, __, and __.
a) At the same time, the __ are inhibited.
- A. pathways, reflex arc
- B. Reflex Arcs
- 1) reflex arc; sensory receptor; sensory neuron; interneuron in the spinal cord; motor neuron; effector
- C. Reflex Behavior
- 1) reflexes; stimuli; homeostasis (HR, BP, etc.); (vomiting, sneezing, swallowing, etc.)
- 2) knee-jerk reflex (patellar tendon reflex); monosynaptic reflex (no interneuron)
- 3) withdrawal reflex, sensory neurons, interneurons, motor neurons
- a. antagonistic extensor muscles
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Meninges
A) The brain and spinal cord are surrounded by membranes called __ that lie between the bone and the soft tissues.
B. The outermost __ is made up of tough, white dense connective tissue, contains many __, and is called the __.
1) It forms the __ of the skul bones.
2) The sheath around the spinal cord is separated from the vertebrae by an __.
C. The middle __, the __, is thin and lacks blood vessels.
1) Between the __ and __ is a __ containing __.
D. The innermost __ is thin and contains many blood vessels and nerves.
1) It is attached to the surface of the brain and spinal cord and follows their contours.
- A) meninges
- B) meninx, blood vessels, dura mater
- 1) inner periosteum
- 2) epidural space
- C) meninx, arachnoid mater
- 1) arachnoid and pia maters, subarachnoid space, cerebrospinal fluid
- D) pia mater
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Spinal Cord
A. The spinal cord begins at the __ and extends as a __ to the level of the __ between the first and second __.
B. Structure of the Spinal Cord
1) The spinal cord consists of __, each of which gives rise to a pair of __.
2) A __ gives rise to the nerves leading to the __, and a __ gives rise to those innervating the __.
3) Two deep __ (__ and __) divide the cord into __ and __.
4) __, made up of bundles of __ (__), surrounds a butterfly-shaped core of __ housing __.
5) A __ contains __.
C. Functions of the Spinal Cord
1) The spinal cord has two major functions: __ + __
2) __ carrying sensory information to the brain are called __; __ carry motor information from the brain.
3) Many __ also pass through the spinal cord.
- A. base of the brain; slender cord; intervertebral disk; lumbar vertebrae
- B1) 31 segments; spinal nerves
- B2) cervical enlargement; upper limbs; lumbar enlargement; lower limbs
- B3) longitudinal grooves (anterior median fissure and posterior median sulcus); right and left halves
- B4) White matter; myelinated nerve fibers (nerve tracts); gray matter; interneurons
- B5) central canal; cerebrospinal fluid
- C1) to transmit impulses to and from the brain; to house spinal reflexes
- C2) tracts; ascending tracts; descending tracts
- C3) spinal reflexes
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