Term
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Definition
Operates under conscious control
Seldom affects long-term survival
Controls skeletal muscles |
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Term
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Definition
Operates without conscious instruction
Controls visceral effectors
Coordinates system functions:
cardiovascular, respiratory, digestive, urinary, reproductive |
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Term
| Autonomic integrative centers |
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Definition
located in hypothalamus
These neurons comparable to upper motor neurons in SNS |
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Term
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Definition
Visceral motor neurons in the brain stem and spinal cord, they extend to ganglia
Part of visceral reflex arcs-most of their activities represent direct reflex responses
Axons of preganglionic neurons-preganglionic fibers
Leave CNS and synapse on ganglionic neurons (PNS) |
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Term
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Definition
Visceral motor neurons in peripheral ganglia
-Contain many ganglionic neurons-autonomic ganglia
Axons of ganglionic neurons-postganglionic fibers
Innervate visceral effectors:
cardiac muscle, smooth muscle, glands, adipose tissue |
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Term
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Definition
Increases alertness, metabolic rate, muscular abilities
"Fight or Flight"
Kicks in only during exertion,stress, or emergency |
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Term
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Definition
Reduces metabolic rate and promotes digestion
"Rest and Digest"
Predominates during resting conditions |
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Term
| 7 responses to increased sympathetic activity |
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Definition
1. Heightened mental alertness
2. Increased metabolic rate
3. Reduced digestive and urinary functions
4. Energy reserves activated
5. Increased respiratory rate and respiratory passages dilate
6. Increased heart rate and blood pressure
7. Sweat glands activated |
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Term
| 5 Responses to Parasympathetic activity |
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Definition
1. Decreased metabolic rate
2. Decreased heart rate and blood pressure
3. Increased salivary and digestive glands secretions
4. Increased motility and blood flow in digestive tract.
5. Urination and defecation stimulation |
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Term
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Definition
Extensive network in digestive tract walls
-over 100 million neurons
Sympathetic, parasympathetic influence
Many complex visceral reflexes coordinated locally without instruction from CNS |
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Term
| Where are the preganglionic neurons located? |
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Definition
Between segments T1 and L2 of spinal cord
Cell bodies are located in the lateral gray horns |
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Term
| Where are the ganglionic neurons located? |
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Definition
| In ganglia near vertebral column |
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Term
| In what 3 locations do you find ganglionic neurons? |
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Definition
1. On both sides of the vertebral column (sympathetic chain ganglia). Control effectors in body wall, thoracic cavity, head, and limbs.
2. anterior to vertebral bodies (collateral ganglia). innervate tissues and organs in abdominopelvic cavity
3. Suprarenal medulla. modified ganglion. Very short axons, release neurotransmitters into the bloodstream, not at a synapse. Function as hormones affecting target cells throughout the body. |
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Term
| Where do sympathetic preganglionic fibers originate? |
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Definition
| from the lateral gray horns |
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Term
| What do ventral roots of spinal segments T1-L2 contain and what do they give rise to? |
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Definition
| They contain sympathetic preganglionic fibers which give rise to myelinated white ramus |
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Term
| What does the white ramus do? |
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Definition
| Carries myelinated preganglionic fibers into a nearby sympathetic chain ganglion. |
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Term
| Sympathetic Chain Ganglia |
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Definition
Only spinal nerves T1-L2 have white rami
Every spinal nerve has a gray ramus that carries sympathetic postganglionic fibers for distribution in the body wall. |
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Term
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Definition
preganglionic fibers that innervate collateral ganglia
In dorsal wall of abdominal cavity |
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Term
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Definition
Abdominopelvic viscera receive sympathetic innervation via sympathetic preganglionic fibers that pass through sympathetic chain without synapsing
-synapse in collateral ganglia |
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Term
| General functions of collateral ganglia |
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Definition
1. Reduce blood flow and energy use by organs that are not important to immediate survival
2. Release stored energy |
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Term
| What 3 collateral ganglia do the splanchnic nerves innervate? |
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Definition
1. The celiac ganglion-postganglionic fibers from this ganglion innervate the stomach, liver, gall bladder, pancreas, and spleen.
2. Superior mesenteric ganglion-postganglionic fibers innervate the small intestine and the proximal 2/3 of the large intestine
3. Inferior mesenteric ganglion-postganglionic fibers innervate kidney, urinary bladder, terminal portions of the large intestine, and the sex organs |
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Term
| What is the adrenal (suprarenal) medullae? |
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Definition
| It is a modified sympathetic ganglion where preganglionic fibers synapse on neuroendocrine cells |
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Term
| What are neuroendocrine cells? |
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Definition
specialized neurons that secrete hormones into the bloodstream.
They secrete the neurotransmitters epinephrine and norepinephrine.
Epinephrine (adrenaline) makes up 75-80% of the secretory output. |
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Term
| Changes that happen when sympathetic activation occurs |
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Definition
Increased alertness, feel "on edge"
feelings of energy and euphoria
(insensitivity to pain)
Increased heart rate, blood pressure,
breathing rate, and depth of respiration
Mobilization of energy reserves |
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Term
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Definition
| Synapses that use ACh as the transmitter |
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Term
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Definition
| Neurons that release norepinephrine |
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Term
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Definition
| In the sympathetic nervous system, the telodendria form a branching network, with each branch resembling a string of pearls. Each "pearl" is a swollen segment called a varicosity, and is packed with neurotransmitter vesicles. |
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Term
| Where are the varicosities that release ACh? |
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Definition
| In the body wall, the skin, the brain, and skeletal muscles. |
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Term
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Definition
Release nitric oxide (NO) as a transmitter
Neurons innervate smooth muscles in walls of blood vessels in skeletal muscles and brain
Produce vasodilation and increased blood flow. |
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Term
| 2 types of adrenergic receptors |
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Definition
Alpha receptors (NE more potent)
Beta receptors
These receptors are G-protein receptors
-Activate 2nd messengers via G-proteins
-2nd messenger: chemical messenger that is not a protein (Ca2+, cAMP) |
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Term
| 2 types of alpha receptors |
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Definition
A1:
More common type of alpha receptor
Releases intracellular Ca2+ into cytosol from reserves in ER
Has excitatory effect on target cell
A2:
Lowers cAMP levels in cytoplasm
Has inhibitory effect on target cell
Helps coordinate sympathetic and parasympathetic activities |
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Term
| Where are beta receptors located? |
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Definition
| on the plasma membranes of cells in many organs, including skeletal muscles, lungs, heart, and liver. |
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Term
| 3 types of beta receptors |
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Definition
!. B1: increases metabolic activity
2. B2: triggers relaxation of smooth muscles along respiratory tract, causing respiratory passages to dilate.
3. B3: found in adipose tissue. Stimulation of B3 receptors leads to lipolysis, the breakdown of triglycerides |
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Term
| The parasympathetic Division consists of? |
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Definition
Preganglionic neurons in the brain stem and in sacral segments of the spinal cord.
Ganglionic neurons in peripheral ganglia within or adjacent to the target organs. |
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Term
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Definition
A ganglion located near the target organ, usually paired.
- |
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Term
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Definition
A ganglion that is embedded in the tissues of the target organ.
-Interconnected masses,clusters of ganglion cells |
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Term
| Major effects of parasympathetic division: |
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Definition
Constriction of the pupils
Secretion by digestive glands-exocrine and endocrine
The Secretion of hormones-nutrient absorption and utilization
Changes in blood flow and glandular activity-sexual arousal
Increase in smooth muscle activity along digestive tract
Defecation-stimulation and coordination
Contraction of urinary bladder during urination
Constriction of respiratory passageways
Reduction in heart rate and force of contraction |
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Term
| All parasympathetic neurons release ___as a neurotransmitter. |
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Definition
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Term
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Definition
| Acetylcholinesterase (AChE) |
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Term
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Definition
Provides preganglionic parasympathetic innervation to structures in:
Neck
Thoracic and abdominopelvic cavity as distal as a distal portion of large intestion
Provides 75% of all parasympathetic outflow
Branches intermingle with fibers of sympathetic division forming plexuses |
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Term
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Definition
Preganglionic fibers in the sacral segments of the spinal cord
Innervate intramural ganglia in the walls of the kidneys, urinary bladder, terminal portions of the large intestine, and sex organs |
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Term
| Signs of nicotine poisoning |
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Definition
Vomiting, diarrhea, high blood pressure, rapid heart rate, sweating, profuse salivation, convulsions
May result in coma or death |
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Term
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Definition
| On surfaces of ganglionic cells (sympathetic and parasympathetic), causes excitation of ganglionic neuron or muscle fiber |
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Term
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Definition
At cholinergic neuromuscular or neuroglandular junctions (parasympathetic) and a few cholinergic junctions (sympathetic)
G-protein receptors-effects last longer than nicotinic receptors, response reflects activation or inactivation of specific enzymes, can be excitatory or inhibitory |
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Term
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Definition
Found in mushrooms
Targets parasympathetic neuromuscular or neuroglandular junctions
Signs and symptoms of poisoning:
salivation, nausea, vomiting, diarrhea, constriction of respiratory passageways, low blood pressure, slow heart rate |
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Term
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Definition
Parasympathetic postganglionic fibers accompany cranial nerves to peripheral destinations
Sympathetic innervation reaches same structures by traveling directly from superior cervical ganglia of sympathetic chain |
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Term
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Definition
| A series of nerve networks in the thoracic and abdominopelvic cavities where the sympathetic postganglionic fibers mingle with parasympathetic preganglionic fibers |
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Term
| What do autonomic motor neurons do? |
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Definition
| They maintain resting level of spontaneous activity |
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Term
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Definition
| Even without stimuli, autonomic motor neurons show a resting level of spontaneous activity. This background level of activity determines an individual's autonomic tone. |
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Term
| When is autonomic tone more important? |
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Definition
| When dual innervation does not occur. |
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Term
| Autonomic tone-no dual innervation |
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Definition
Blood vessel dilates and blood flow increases
Blood vessel constricts and blood flow is reduced.
Background sympathetic tone keeps muscles partially contracted |
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Term
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Definition
autonomic reflexes initiated in the viscera
They provide automatic motor responses that can be modified, facilitated or inhibited by higher centers, especially those of the hypothalamus. |
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Term
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Definition
| Constrict pupils of both eyes |
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Term
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Definition
| Consists of a receptor, a sensory neuron, a processing center (one or more interneurons), and 2 visceral motor neurons |
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Term
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Definition
| Causes pupils to dilate in the dark |
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Term
| sexual arousal (emotional state) |
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Definition
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Term
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Definition
Autonomic equivalent of polysynaptic reflexes
Visceral sensory neurons deliver information to CNS
ANS carries motor commands to visceral effectors
Typically coordinate the activities of an entire organ |
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Term
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Definition
Bypass the CNS entirely
Involve sensory neurons and interneurons located within autonomic ganglia
Interneurons synapse on ganglionic neurons
Motor commands distributed by postganglionic fibers
Control simple motor responses with localized effects-one small part of target organ |
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Term
| 3 characteristics of higher-order functions (memory, learning) |
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Definition
1. The cerebral cortex is required.
2. They involve both conscious and unconscious information processing
3. They are NOT part of the programmed "wiring" of the brain, subject to adjustment over time. |
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Term
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Definition
| Specific bits of information, such as the color of a stop sign |
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Term
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Definition
Learned motor behaviors
-Incorporated at unconscious level with repetition
-Programmed behaviors are stored in appropriate area of brain stem
-Complex skill memories involve the integration of motor patterns in the basal nuclei, cerebral cortex, and cerebellum |
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Term
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Definition
Do not last long
While they last, the information can be recalled immediately
Contain small bits of information |
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Term
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Definition
1. Secondary memories: fade with time and require effort to recall
2. Tertiary memories: are with you for a lifetime |
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Term
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Definition
| The conversion from short-term to long-term memory |
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Term
| Brain regions involved in memory consolidation and access |
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Definition
Amygdaloid body (amygdala),Hippocampus (2 components of the limbic system)
Nucleus basalis
Cerebral cortex |
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Term
| Damage to the Amygdaloid body and hippocampus may cause ___________. |
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Definition
Inability to convert short-term memories to new long-term memories
Existing long-term memories remain intact and accessible |
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Term
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Definition
Cerebral nucleus near diencephalon
Plays uncertain role in memory storage and retrieval
Tracts connect with hippocampus, amygdaloid body, and cerebral cortex
Damage changes emotional states, memor, and intellectual functions |
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Term
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Definition
Stores long-term memories
Conscious motor and sensory memories referred to association areas
Occipital and temporal lobes:
Special portions crucial to memories of faces, voices, and words
A specific neuron my be activated by a combination of sensory stimuli associated with a particular individual; called grandmother cells |
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Term
| Cellular mechanisms of memory formation and storage |
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Definition
Involves anatomical and physiological changes in neurons and synapses
Increased neurotransmitter release
Facilitation at synapses
Formation of additional synaptic connections |
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Term
| Increased Neurotransmitter release |
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Definition
Frequently active synapse increases the amount of neurotransmitter it stores
Releases more on each stimulation
The more neurotransmitter released, the greater the effect on the postsynaptic neurons. |
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Term
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Definition
Neural circuit repeatedly activated
Synaptic terminals begin continuously releasing neurotransmitter
Neurotransmitter binds to receptors on postsynaptic membrane
Produces graded depolarization
Brings membrane closer to threshold
Facilitation results affect all neurons in the circuit. |
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Term
| Formation of additional synaptic connections |
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Definition
Neurons repeatedly communicating
Axon tip branches and forms additional synapses on postsynaptic neuron
Presynaptic neuron has greater effect on transmembrane potential of postsynaptic neuron |
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Term
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Definition
single circuit corresponds to single memory, forms as a result of experience and repetition
Efficient conversion of short-term memory takes at least 1 hour, repetition crucial |
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Term
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Definition
Nature, intensity, and frequency of original stimulus
Strong, repeated, and exceedingly pleasant or unpleasant events likely converted to long-term memories |
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Term
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Definition
Also called slow-wave sleep or non-REM sleep
Entire body relaxes
Cerebral cortex activity minimal
Heart rate, blood pressure, respiratory rate, and energy utilization decline up to 30% |
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Term
| Rapid eye movement (REM) sleep |
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Definition
Active dreaming occurs
Changes in blood pressure and respiratory rate
Less receptive to outside stimuli than in deep sleep
Muscle tone decreases markedly
Intense inhibition of somatic motor neurons
Eyes move rapidly as dream events unfold |
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Term
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Definition
Alternates between levels
Begins in deep sleep, lasts about 1-1.5 hours
REM periods average 5 minutes in length, increase to 20 minutes over 8 hours |
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Term
| What impact does sleep have on the CNS? |
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Definition
Produces only minor changes in physiological activities of organs and systems
Protein synthesis in neurons increases during sleep
Extended periods without sleep lead to disturbances in mental function
25% of U.S.population experiences sleep disorders |
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Term
| Function of the reticular activating system |
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Definition
Arousal, awaking from sleep
diffuse network in reticular formation extends from the medulla oblongata to the mesencephalon
Output of RAS projects to thalamic nuclei that influence large areas of cerebral cortex
When RAS inactive, so is cerebral cortex; stimulation of the RAS produces widespread activation of the cerebral cortex |
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Term
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Definition
Destruction of ACh-secreting and GABA-secreting neurons in basal nuclei
Symptoms appear as basal nuclei and frontal lobes slowly degenerate
Difficulty controlling movements
Intellectual abilities gradually decline |
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Term
| LSD (Lysergic Acid Diethylamide) |
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Definition
Powerful hallucinogenic drug that affects sensory interpretation and emotional states
Activates serotonin receptors in brain stem, hypothalamus, and limbic system |
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Term
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Definition
Not enough serotonin, activation blocked
Prozac, Paxil, Zoloft, Luvox, Celexa, slows removal of serotonin |
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Term
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Definition
| Inadequate dopamine production causes motor problems |
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Term
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Definition
Stimulated dopamine production
Large doses can produce symptoms resembling schizophrenia |
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Term
| Aging and the Nervous system |
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Definition
A reduction in the brain size and weight
-narrower gyri and wider sulci
-decrease in volume of the cerebral cortex
-larger subarachnoid space
Reduction in number of neurons
-Brain shrinkage linked to loss of cortical neurons
-No neuronal loss in brain stem nuclei
Decrease in blood flow to the brain |
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Term
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Definition
Fatty deposits in walls of blood vessels
Reduces blood flow through arteries
Increases chances of rupture
May damage surrounding neural tissue
Increase chances of a cerebrovascular accident (stroke) |
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Term
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Definition
| granular pigment with no known function |
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Term
| Changes in the synaptic organization of the brain due to aging |
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Definition
The number of dendritic branches, spines, and interconnections decreases, synaptic connections are lost
The rate of neurotransmitter production declines |
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Term
| Intracellular and Extracellular changes in CNS neurons due to aging |
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Definition
Neurons in brain accumulate abnormal intracellular deposits:
Lipofuscin-granular pigment with no known function
Neurofibrillary tangles-masses of neurofibrils form dense mats inside cell body and axon
Plaques-extracellular accumulations of fibrillar proteins surrounded by abnormal dendrites and axons
Plaques and tangles contain 2 forms of amyloid B proteins (fibrillar and soluble)
Appear in brain regions specifically associated with memory processing |
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Term
| Anatomical changes linked to functional changes |
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Definition
Neural processing becomes less efficient with age
Memory consolidation more difficult
Secondary memories harder to access
Sensory Systems:
hearing, balance, vision, smell, and taste become less acute
reaction times are slowed, reflexes weaken or disappear
Motor control:
precision decreases
takes longer to perform |
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Term
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Definition
Most common cause of senile dementia
abnormal plaques, neurofibrillary tangles in regions associated with memory, emotion, and intellectual function |
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