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305 Cards in this Set
- Front
- Back
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Medulla Oblongata
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cranial nerves XII, XI, X, IX, and part of VIII
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Medulla Oblongata
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-cardiac center (heart rate and force of contraction) -vasomotor center (regulation of blood vessel diameter)
-basic rhythm of breathing -swallowing -coughing -speech -sneezing -gagging -vomiting gastrointestinal secretion -sweating |
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cranial nerves XII, XI, X, IX, and part of VIII
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Medulla Oblongata
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-cardiac center (heart rate and force of contraction) -vasomotor center (regulation of blood vessel diameter)
-basic rhythm of breathing -swallowing -coughing -speech -sneezing -gagging -vomiting gastrointestinal secretion -sweating |
Medulla Oblongata
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Pons
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cranial nerves part of VIII, VII, VI, and V
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cranial nerves part of VIII, VII, VI, and V
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Pons
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Pons
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-altered rhythms of breathing
-relaying information between cerebrum and cerebellum -sleep -hearing -equilibrium -taste -eye movements -facial expressions -facial sensation -swallowing -bladder control -posture |
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-altered rhythms of breathing
-relaying information between cerebrum and cerebellum -sleep -hearing -equilibrium -taste -eye movements -facial expressions -facial sensation -swallowing -bladder control -posture |
Pons
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DORSAL MIDBRAIN (TECTUM)
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cranial nerves IV and III
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cranial nerves IV and III
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DORSAL MIDBRAIN (TECTUM)
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DORSAL MIDBRAIN (TECTUM)
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SUPERIOR COLLICULI
INFERIOR COLLICULI |
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INFERIOR COLLICULI
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auditory attention
auditory reflexes equilibrium reflexes |
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SUPERIOR COLLICULI
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visual attention
visual reflexes |
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RETICULAR FORMATION
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-somatic motor control
-central pattern generators for breathing and swallowing -cardiovascular control -pain modulation -sleep and consciousness |
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-somatic motor control
-central pattern generators for breathing and swallowing -cardiovascular control -pain modulation -sleep and consciousness |
RETICULAR FORMATION
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DIENCEPHALON
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THALAMUS
HYPOTHALAMUS |
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HYPOTHALAMUS
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-hormone secretion control -autonomic effects -thermoregulation
-food and water intake -sleep and circadian rhythms -memory -emotional behavior |
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THALAMUS
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-receiving all incoming sensory information, except smell, and then relaying that information to the cerebral cortex
-emotional and memory functions -crude perception |
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-receiving all incoming sensory information, except smell, and then relaying that information to the cerebral cortex
-emotional and memory functions -crude perception |
THALAMUS
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-hormone secretion control -autonomic effects -thermoregulation
-food and water intake -sleep and circadian rhythms -memory -emotional behavior |
HYPOTHALAMUS
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THALAMUS
HYPOTHALAMUS |
DIENCEPHALON
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EPITHALAMUS (the PINEAL GLAND)
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day-night cycles
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day-night cycles
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EPITHALAMUS (the PINEAL GLAND)
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CEREBELLUM
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functions in control of smooth, sequential, and coordinated skeletal muscle movements, muscle tone, posture. Some evidence that it is involved in judging the passage of time, awareness, judgment, and memory.
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functions in control of smooth, sequential, and coordinated skeletal muscle movements, muscle tone, posture. Some evidence that it is involved in judging the passage of time, awareness, judgment, and memory.
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CEREBELLUM
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CEREBRUM
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PRIMARY SENSORY AREAS
SENSORY ASSOCIATION AREAS MOTOR ASSOCIATION (PREMOTOR) AREA PRIMARY MOTOR AREAS CEREBRAL NUCLEI (BASAL GANGLIA) LIMBIC SYSTEM |
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PRIMARY SENSORY AREAS
SENSORY ASSOCIATION AREAS MOTOR ASSOCIATION (PREMOTOR) AREA PRIMARY MOTOR AREAS CEREBRAL NUCLEI (BASAL GANGLIA) LIMBIC SYSTEM |
CEREBRUM
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PRIMARY SENSORY AREAS
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receive sensory input from the thalamus
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receive sensory input from the thalamus
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PRIMARY SENSORY AREAS
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SENSORY ASSOCIATION AREAS
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associate sensory input with memory/function
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associate sensory input with memory/function
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SENSORY ASSOCIATION AREAS
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MOTOR ASSOCIATION (PREMOTOR) AREA
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initiates the intention to contract a skeletal muscle
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initiates the intention to contract a skeletal muscle
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MOTOR ASSOCIATION (PREMOTOR) AREA
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PRIMARY MOTOR AREAS
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– project descending fibers that ultimately cause skeletal muscle contraction
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– project descending fibers that ultimately cause skeletal muscle contraction
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PRIMARY MOTOR AREAS
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CEREBRAL NUCLEI (BASAL GANGLIA)
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planning and execution of movements,
control of highly practiced movements, related to control of muscle tone and posture |
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planning and execution of movements,
control of highly practiced movements, related to control of muscle tone and posture |
CEREBRAL NUCLEI (BASAL GANGLIA)
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LIMBIC SYSTEM
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emotion, smell, memory
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emotion, smell, memory
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LIMBIC SYSTEM
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FUNCTIONS OF BRAIN GRAY MATTER
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-MEDULLA OBLONGATA
-PONS -DORSAL MIDBRAIN (TECTUM) -RETICULAR FORMATION -DIENCEPHALON a.) THALAMUS b.) HYPOTHALAMUS -EPITHALAMUS (the PINEAL GLAND -CEREBELLUM -CEREBRUM |
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What three functions does the nervous system serve?
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1. senses changes in the environment, both internal and external
2. integrates and interprets the sensory input for understanding 3. responds by initiating muscular contractions or glandular secretions |
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How does the nervous system accomplish its homeostatic role?
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These reactions, carried out by electrical messages called nerve impulses (action potentials), allow for second-to-second adjustments in homeostasis.
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How does the role of the endocrine system compare with that of the nervous system?
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The endocrine system, using blood-borne chemical messengers called hormones, controls long-term homeostasis. Rather than making second-to-second adjustments, the endocrine system controls processes over days, weeks, months, and years.
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Name the two principal divisions of the nervous system.
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central nervous system (CNS)
peripheral nervous system (PNS) |
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Describe the central and peripheral nervous systems.
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The CNS consists of the brain and the spinal cord, within which incoming sensory information is processed, thoughts and emotions are generated, and memories are stored. Most nerve impulses that stimulate muscle contraction and glandular secretion originate in the CNS.
The PNS consists of 12 pairs of cranial nerves associated with the brain and 31 pairs of spinal nerves associated with the spinal cord. |
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What is the relationship between the two systems?
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Cranial and spinal nerves of the PNS carry sensory information from the CNS to effectors (muscles and glands) in the periphery.
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What are sensory neurons?
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The input component of the PNS consists of nerve cells called sensory (afferent) neurons that conduct nerve impulses from sensory receptors to the CNS and end within the CNS.
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What are motor neurons?
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The output component of the PNS consist of nerve cells called motor (efferent) neurons that originate in the CNS and conduct nerve impulses away from the CNS to the effectors.
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Compare the somatic with the autonomic nervous system.
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The somatic nervous system is concerned with sensory information from the skin, skeletal muscles, and special senses, and motor information to the skeletal muscle only.
The autonomic nervous system carries sensory information from the viscera to the CNS and motor information from the CNS to cardiac muscle, smooth muscles, and glands. |
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Name the autonomic nervous system subdivisions
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sympathetic
parasympathetic |
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What are neuroglial cells?
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the supportive, nurturing, and protective cells for the neurons. They occupy only half of the CNS, are much smaller than neurons and outnumber them. They remain mitotic throughout life and tend to fill in spaces of injured neurons after disease and injury.
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Name and then briefly describe the six types of neuroglial cells.
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1. Astrocytes
-attach blood vessels to neurons -help to form the blood-brain barrier. -help maintain proper balance of K+ for the neurons -participate in the metabolism of neurotransmitters. -responsible for forming scars in the CNS after injury. 2. Oligodendrocytes -give support to neurons of the CNS. -produce the myelin sheath found around axons of the CNS -uses its processes to wrap several axons. 3. Microglia -small phagocytic cells that engulf & destroy microbes and cellular debris in the CNS. -migrate to areas of injured nervous tissue and help to clean the area. 4. Ependyma -form a continuous epithelial lining for the ventricles of the brain and the central canal of the spinal cord. -assist in the circulation of cerebrospinal fluid, but their role is mostly unknown. 5. Schwann cells -produce the myelin sheath around the axons of motor neurons and the dendrites of sensory neurons in the PNS. 6. Satellite cells -support neurons found in ganglia in the PNS; function is obscure. |
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-support neurons found in
ganglia in the PNS; function is obscure. |
6. Satellite cells
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-produce the myelin sheath around the axons of motor neurons and the dendrites of sensory neurons in the PNS.
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5. Schwann cells
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6. Satellite cells
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-support neurons found in
ganglia in the PNS; function is obscure. |
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5. Schwann cells
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-produce the myelin sheath around the axons of motor neurons and the dendrites of sensory neurons in the PNS.
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-form a continuous epithelial
lining for the ventricles of the brain and the central canal of the spinal cord. -assist in the circulation of cerebrospinal fluid, but their role is mostly unknown. |
4. Ependyma
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4. Ependyma
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-form a continuous epithelial
lining for the ventricles of the brain and the central canal of the spinal cord. |
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-small phagocytic cells that engulf & destroy microbes and cellular debris in the CNS.
-migrate to areas of injured nervous tissue and help to clean the area. |
3. Microglia
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3. Microglia
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-small phagocytic cells that engulf & destroy microbes and cellular debris in the CNS.
-migrate to areas of injured nervous tissue and help to clean the area. |
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2. Oligodendrocytes
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-give support to neurons of the CNS.
-produce the myelin sheath found around axons of the CNS -uses its processes to wrap several axons. |
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-give support to neurons of the CNS.
-produce the myelin sheath found around axons of the CNS -uses its processes to wrap several axons. |
2. Oligodendrocytes
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1. Astrocytes
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-attach blood vessels to neurons
-help to form the blood-brain barrier. -help maintain proper balance of K+ for the neurons -participate in the metabolism of neurotransmitters. -responsible for forming scars in the CNS after injury. |
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-attach blood vessels to neurons
-help to form the blood-brain barrier. -help maintain proper balance of K+ for the neurons -participate in the metabolism of neurotransmitters. -responsible for forming scars in the CNS after injury. |
1. Astrocytes
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What is the myelin sheath?
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Most nerve fibers are surrounded by a multilayered lipoprotein produced by the neuroglia (Schwann cells in the PNS and oligodendrocytes in the CNS) called the myelin sheath.
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What is the myelin sheath's function?
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The sheath electrically insulates the nerve fiber, greatly increasing the speed of nerve impulse conduction.
Nerve processes with such a covering are said to be myelinated while those without are unmyelinated. Therefore, there are neurons with different speeds of transmission. |
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How is it formed in the PNS?
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Schwann cells form the myelin sheath around motor axons and sensory dendrites during fetal life and the first postnatal year. In this process, Schwann cells line up along the length of the nerve fiber, attach to it, then begin to spiral around it, leaving behind multiple layers of glial cell membrane.
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What is the neurilemma?
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As the multiple layers of membrane are formed, the cytoplasm and organelles of the Schwann cells are pushed to the outside. This portion of the Schwann cell is known as the neurilemma. It is found only around neurons of the PNS; oligodendrocytes do not form a neurilemma.
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What are the nodes of Ranvier?
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At intervals along the length of a nerve process, between the individual Schwann cells (PNS) or pieces of oligodendrocytes (CNS), are gaps in the myelin sheath called the nodes of Ranvier (neurofibral nodes).
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What is the function of neurons?
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Nerve cells, called neurons, are responsible for conducting impulses from one part of the body to another and are therefore the structural and functional units of the nervous system.
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Neuron Cell body
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(perikaryon, soma) contains
typical cellular organelles surrounded by cytoplasm. There is a large nucleus with a very prominent nucleolus and neurofibrils, elements of the cytoskeleon that give the neuron structure and shape. |
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(perikaryon, soma) contains
typical cellular organelles surrounded by cytoplasm. There is a large nucleus with a very prominent nucleolus and neurofibrils, elements of the cytoskeleon that give the neuron structure and shape. |
Neuron Cell body
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Nissl substance
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Scattered throughout the cytoplasm of the
cell body are structures called Nissl bodies, orderly arrays of rough endoplasmic reticulum used for protein synthesis. |
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Scattered throughout the cytoplasm of the
cell body are structures called Nissl bodies, orderly arrays of rough endoplasmic reticulum used for protein synthesis. |
Nissl substance
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Dendrite
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short, tapering, and
highly branched process extending from the cell body; usually unmyelinated (sensory dendrites are the exception). It is ALWAYS a process that carries the nervous message towards the cell body. |
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short, tapering, and
highly branched process extending from the cell body; usually unmyelinated (sensory dendrites are the exception). It is ALWAYS a process that carries the nervous message towards the cell body. |
Dendrite
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Axon
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The axon is a single, long, thin, cylindrical projection
from the cell body that moves toward an effector or another neuron. It ALWAYS carries the nervous message away from the cell body. |
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single, long, thin, cylindrical projection
from the cell body that moves toward an effector or another neuron. It ALWAYS carries the nervous message away from the cell body. |
Axon
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Axon hillock
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The axon hillock, a cone-shaped elevation, is
that region of the neuronal cell body from which the axon arises. |
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a cone-shaped elevation, is
that region of the neuronal cell body from which the axon arises. |
Axon hillock
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Trigger zone
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Just distal to the axon hillock is an area called the trigger zone where nerve impulses arise for propagation along the axon. This area of membrane is rich with voltage-gated sodium channels (to be described later).
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Just distal to the axon hillock is an area called the trigger zone where nerve impulses arise for propagation along the axon. This area of membrane is rich with voltage-gated sodium channels (to be described later).
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Trigger zone
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Axon collateral
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Along the axon’s length, side branches
called axon collaterals may depart from the main axon to innervate other structures. |
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Along the axon’s length, side branches
called axon collaterals may depart from the main axon to innervate other structures. |
Axon collateral
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Telodendrion
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At their terminations with effectors, the axon
and axon collaterals end by dividing into many fine processes called axon terminals or telodendria. |
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At their terminations with effectors, the axon
and axon collaterals end by dividing into many fine processes called axon terminals or _______ |
Telodendrion
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End bulbs
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The tips of the axon terminals swell into bulb-shaped synaptic end-bulbs that contain synaptic vesicles filled with a chemical known as a neurotransmitter. Neurons utilize a single type of neurotransmitter.
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The tips of the axon terminals swell into bulb-shaped synaptic end-bulbs that contain synaptic vesicles filled with a chemical known as a neurotransmitter. Neurons utilize a single type of neurotransmitter.
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End bulbs
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A nerve fiber is …?
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a general term for any nerve process (sensory dendrite or motor axon).
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A nerve is …?
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a bundle of many nerve fibers, both sensory and motor, that course along the same path in the PNS.
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A tract is …?
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a bundle of related nerve fibers in the CNS that connects different areas of the CNS.
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Multipolar neurons
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usually have several
dendrites and a single axon; most neurons are of this type. |
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usually have several
dendrites and a single axon; most neurons are of this type. |
Multipolar neurons
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Bipolar neuron
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Bipolar neurons have a single dendrite and a
single axon extending from the cell body; associated with the special senses. |
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Bipolar neurons have a single dendrite and a
single axon extending from the cell body; associated with the special senses. |
Bipolar neuron
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Unipolar
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(sensory only) have a single
process extending from the cell body called the central process that divides into two parts. The axonal portion carries an impulse away from the cell body; the dendritic portion is attached to a receptor distally and carries an impulse to the cell body. |
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(sensory only) have a single
process extending from the cell body called the central process that divides into two parts. The axonal portion carries an impulse away from the cell body; the dendritic portion is attached to a receptor distally and carries an impulse to the cell body. |
Unipolar
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gray matter vs. white matter
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gray matter is areas of nerve cell bodies, dendrites, axon terminals, and/or unmyelinated axons, and neuroglia.
white matter is aggregations of myelinated processes of many neurons, arranged into tracts. |
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Gray matter
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gray matter is areas of nerve cell bodies, dendrites, axon terminals, and/or unmyelinated axons, and neuroglia.
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areas of nerve cell bodies, dendrites, axon terminals, and/or unmyelinated axons, and neuroglia.
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Gray matter
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aggregations of myelinated processes of many neurons, arranged into tracts.
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white matter
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white matter
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white matter is aggregations of myelinated processes of many neurons, arranged into tracts.
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nucleus vs. ganglion
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A nucleus is a collection of similar neuronal
cell bodies and dendrites within the gray matter of the CNS that perform a specific function. These collections of neurons are often called centers. A ganglion is a collection of similar neuronal cell bodies outside the CNS, lying in the periphery. Ganglia contain the cell bodies of sensory neurons or the second neuronal cell body of an autonomic pathway. |
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nucleus
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collection of similar neuronal
cell bodies and dendrites within the gray matter of the CNS that perform a specific function. These collections of neurons are often called centers. |
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collection of similar neuronal
cell bodies and dendrites within the gray matter of the CNS that perform a specific function. These collections of neurons are often called centers. |
nucleus
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ganglion
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A ganglion is a collection of similar neuronal cell bodies outside the CNS, lying in the periphery. Ganglia contain the cell bodies of sensory neurons or the second neuronal cell body of an autonomic pathway.
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a collection of similar neuronal cell bodies outside the CNS, lying in the periphery. Ganglia contain the cell bodies of sensory neurons or the second neuronal cell body of an autonomic pathway.
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ganglion
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Communication by neurons depends upon two basic properties of their cell membranes
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1. There is an electrical voltage, called the resting membrane potential
(RMP), across the cell membrane. 2. Their cell membranes contain a variety of ion channels (pores) that may be open or closed. |
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What is a membrane channel?
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A membrane channel (pore) allows a specific substance to move through
a water-filled passageway to either enter or leave the cell. In neuronal membranes, sodium and potassium channels are of utmost importance. |
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Assuming that there is a diffusion gradient, what happens when a channel opens?
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When the channels are open, specific ions in the intracellular fluid or the extracellular fluid flow through them, according to their diffusion gradients.
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Describe the concept of the channel as a gate or door.
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Part of the integral protein that forms such a channel may act as a gate or door, opening and closing on demand, to alter the flow of ions along their diffusion gradient.
Depending on the types of channels that are present, a portion of a neuron may be able to produce either a gradient potential or and action potential (nerve impulse). |
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What is the resting membrane potential?
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(RMP) occurs because there is a small build up of negative charges just inside the cell membrane of the neuron and an equal build up of positive charges outside.
A cell that exhibits a membrane potential is called a polarized cell or has a polarized membrane. |
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What is current? What are the paths for ion flow through the neuronal membrane?
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In living cells, this current is created when the ions flow across the membrane.
Since the lipid bilayer is a good insulator, the main paths for current flow across the membrane are the ion channels. Thus, when the ion channels are open in the membrane, current flows and this changes the membrane potential. |
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Describe the two main factors related to ions that contribute to the resting membrane potential.
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1. Distribution of ions across the cell membrane.
--extracellular fluid is rich in Na+ and Cl- --intracellular fluid is rich in K+ and anions such as organophosphates and proteins 2. Relative permeability of the cell membrane to Na+ and K+ --membrane is moderately permeable to K+ and Cl-; slightly permeable to Na+; impermeable to intracellular anions. |
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Why does the inside of the neuronal cell membrane become negatively-charged?
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Since the membrane is moderately permeable to potassium, there is always a slow diffusion of positively-charged potassium ions out of the cell. The intracellular fluid just next to the inner surface of the neuronal membrane becomes more and more negatively-charged as potassium diffuse out.
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Why does the outside of the neuronal cell membrane become positively-charged?
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Since the neuronal membrane is only slightly permeable to sodium, the sodium ions accumulate outside the cell. They are attracted to the anions within the cell and because of the large diffusion gradient for Na+ into the cell, the extracellular fluid just next to the outer surface of the neuronal membrane becomes more and more positively-charged.
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What is the net result of this ion distribution?
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The net result is that neuronal membrane at rest tends to have positive charges lined up along its outer surface and negative charges lined up along its inner surface.
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It is important that the membrane potential be maintained and that the ions remain in their respective resting positions. With such great diffusion gradients, how is this accomplished?
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In the membrane are Na/K-ATPase pumps that expel 3 Na+ for 2 K+ imported. Such pumps are said to be electrogenic since they contribute to the negativity of the resting membrane potential.
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Describe ion channels
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An ion channel (pore) is a specific membrane protein structure that allows only a specific substance to pass through the membrane while excluding others.
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Describe the different types of ion channels
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1. Leakage (non-gated) channels are always open
(glucose channels, for example) 2. Gated channels open and close in response to some sort of stimulus: voltage, chemical, mechanical, light. |
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Describe how ion channels work?
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Voltage-gated (or regulated) channels open in response to a direct change in the membrane potential (voltage).
The presence of these channels in nerve and muscle cell membranes makes them excitable (irritable); that is, the ability to respond to certain types of stimuli by producing impulses. The trigger zone for a particular neuron is the place where the voltage-gated ion channels are clustered most densely. |
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Chemically-gated channel
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Chemically-gated ion channels open
and close in response to specific chemical stimuli, such as neurotransmitters and hormones. |
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channels that open and close in response to specific chemical stimuli, such as neurotransmitters and hormones.
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Chemically-gated channel
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Mechanically-gated channel --
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Mechanically-gated ion channels
open or close in response to mechanical stimuli such as touch, pressure, or vibration (sensory receptors). |
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channels that open or close in response to mechanical stimuli such as touch, pressure, or vibration (sensory receptors).
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Mechanically-gated channel --
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Light-gated channel
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Light-gated ion channels close in response
to light energy (found only in the photoreceptors of the eyes). |
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channels that close in response
to light energy (found only in the photoreceptors of the eyes). |
Light-gated channel
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Graded response
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an electrical response that varies in size, depending on how many channels are opened and for how long.
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an electrical response that varies in size, depending on how many channels are opened and for how long.
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Graded response
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In general, describe the ion channel events that occur during depolarization and repolarization
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During an action potential (nerve impulse), two types of voltage-gated ion channels open and then close, first the channels for Na+, then those for K+.
Rapid opening of the voltage-gated Na+ channels results in depolarization, the loss and then reversal of the membrane polarization by the neuron. The slower opening voltage-gated K+ channels and the closing of the previously open Na+ channels result in repolarization, the recovery of the resting membrane potential. |
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What is a synapse?
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The point of communication between cells, either neuron-neuron or neuron-effector (“synapsis” = connection)
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Why are synapses essential for homeostasis?
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Because they allow information to be integrated and filtered; some signals are transmitted while others are inhibited.
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Distinguish between presynaptic and postsynaptic neurons.
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At a synapse, the neuron sending the signal is the presynaptic neuron, and the neuron receiving the message is the postsynaptic neuron.
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Excitatory neurotransmitter
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neurotransmitter
released at a synapse causes depolarization, bringing the membrane of the postsynaptic neuron closer to threshold (more positive). |
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neurotransmitter
released at a synapse causes depolarization, bringing the membrane of the postsynaptic neuron closer to threshold (more positive). |
Excitatory neurotransmitter
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Facilitation and summation
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time that the postsynaptic membrane is brought closer to its threshold, it is said to be facilitated. And a series of these, which generates an action potential?
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time that the postsynaptic membrane is brought closer to its threshold, it is said to be facilitated. And a series of these, which generates an action potential?
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Facilitation and summation
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Inhibitory neurotransmitter
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When neurotransmitter causes
hyperpolarization of the postsynaptic membrane, it moves the membrane potential further from threshold (more negative). |
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When neurotransmitter causes
hyperpolarization of the postsynaptic membrane, it moves the membrane potential further from threshold (more negative). |
Inhibitory neurotransmitter
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Spatial summation
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result of
several presynaptic neurons releasing their neurotransmitter into the trigger zone within the same time frame |
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result of
several presynaptic neurons releasing their neurotransmitter into the trigger zone within the same time frame |
Spatial Summation
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Temporal summation
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results from buildup of neurotransmitter released by a single presynaptic neuron firing several times in rapid succession,
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results from buildup of neurotransmitter released by a single presynaptic neuron firing several times in rapid succession,
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Temporal summation
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Neurotransmitter Remover:
Diffusion |
The neurotransmitter may diffuse through the
extracellular fluid and away from the synapse. |
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The neurotransmitter may diffuse through the
extracellular fluid and away from the synapse. |
Neurotransmitter Remover:
Diffusion |
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Neurotransmitter Remover:
Enzymatic degradation |
There may be specific enzymes
present in the synaptic cleft or on the postsynaptic membrane to degrade the neurotransmitter. |
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There may be specific enzymes
present in the synaptic cleft or on the postsynaptic membrane to degrade the neurotransmitter. |
Neurotransmitter Remover:
Enzymatic degradation |
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|
Neurotransmitter Remover:
Uptake into the cell |
In some cases the neurotransmitter is
actively transported back into the presynaptic neuron and reused. |
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In some cases the neurotransmitter is
actively transported back into the presynaptic neuron and reused. |
Neurotransmitter Remover:
Uptake into the cell |
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|
What is a neuronal pool?
|
The CNS contains billions of neurons organized into complex patterns called neuronal pools, each with its own role in homeostasis. Neuronal pools are arranged into patterns called circuits over which nerve impulses are conducted. There are five common types of these circuits.
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Neuronal Circuits:
Simple series |
The simplest circuit is the simple series circuit in
which a single presynaptic neuron synapses with a single postsynaptic neuron, which stimulates another, which stimulates another, etc. |
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a single presynaptic neuron synapses with a single postsynaptic neuron, which stimulates another, which stimulates another, etc.
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Neuronal Circuits:
Simple series |
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Neuronal Circuits:
Diverging |
In a diverging circuit, a single presynaptic neuron
synapses with more than one postsynaptic neuron, in a process called divergence (Ex: a sensory signal is relayed to several different parts of the brain.) |
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|
a single presynaptic neuron
synapses with more than one postsynaptic neuron. (Ex: a sensory signal is relayed to several different parts of the brain.) |
Neuronal Circuits:
Diverging |
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|
Neuronal Circuits:
Parallel after-discharge |
When a single synaptic neuron that diverges, then each neuron in the pathway synapses on a common postsynaptic neuron (Ex: precise mental activities such as math.)
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When a single synaptic neuron that diverges, then each neuron in the pathway synapses on a common postsynaptic neuron (Ex: precise mental activities such as math.)
|
Neuronal Circuits:
Parallel after-discharge |
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|
Neuronal Circuits:
Reverberating |
branches from neurons
later in a pathway synapse with neurons found earlier in the pathway (Ex: breathing, sleep-wake cycles, short-term memory.) |
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branches from neurons
later in a pathway synapse with neurons found earlier in the pathway (Ex: breathing, sleep-wake cycles, short-term memory.) |
Neuronal Circuits:
Reverberating |
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|
Neuronal Circuits:
Converging |
several presynaptic neurons
with a single postsynaptic neuron, in a process known as convergence (Ex: a single motor neuron receives motor information from several sources.) |
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|
several presynaptic neurons
with a single postsynaptic neuron, in a process known as convergence (Ex: a single motor neuron receives motor information from several sources.) |
Neuronal Circuits:
Converging |
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saltatory conduction
|
propagation of a nerve signal that seems to jump from node to node
|
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List the spinal cord's three basic functions.
|
1. The spinal cord and its associated spinal nerves contain neuronal
circuits that mediate spinal reflexes. 2. The spinal cord is the site for integration (summing) of nerve impulses that arise locally or arrive from the periphery and brain. 3. The spinal cord provides the pathways by which sensory nerve impulses reach the brain and motor nerve impulses pass from the brain to motor neurons. |
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What protects the spinal cord?
|
Two types of connective tissue, bone and meninges, plus the cushion of cerebrospinal fluid (CSF), surround and protect the delicate nervous tissue of the brain and spinal cord.
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Where is the spinal cord located?
|
The spinal cord is located within the vertebral (spinal) canal of the vertebral column. The vertebral foramina of the vertebrae, stacked one on top of the other, form the canal.
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What are the meninges?
|
The meninges (singular is meninx) are connective tissue coverings that encircle the spinal cord and brain. There are three layers:
1. Dura mater 2. Arachnoid membrane 3. Pia mater |
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Epidural space
|
located between the
bony wall of the vertebral canal and the outer surface of the dura mater. It is filled with fat and blood vessels. |
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located between the
bony wall of the vertebral canal and the outer surface of the dura mater. It is filled with fat and blood vessels |
Epidural space
|
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Dura mater
|
the outermost meninx, is
dense connective tissue forming a tube enclosing the spinal cord. It extends to the S-2 vertebra, where it closes. |
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the outermost meninx, is
dense connective tissue forming a tube enclosing the spinal cord. It extends to the S-2 vertebra, where it closes. |
Dura mater
|
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Subdural space
|
lies deep to the dura
mater, between it and the arachnoid membrane. It contains a small amount of interstitial fluid. |
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lies deep to the dura
mater, between it and the arachnoid membrane. It contains a small amount of interstitial fluid. |
Subdural space
|
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Arachnoid membrane
|
the middle meninx formed by delicate collagen and elastin fibers. It is avascular.
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the middle meninx formed by delicate collagen and elastin fibers. It is avascular.
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Arachnoid membrane
|
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Subarachnoid space
|
Deep to the arachnoid membrane,
between it and the pia mater. It is filled with cerebrospinal fluid (CSF). |
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Deep to the arachnoid membrane,
between it and the pia mater. It is filled with cerebrospinal fluid (CSF). |
Subarachnoid space
|
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Pia mater
|
inner-most meninx, is a thin
connective tissue that adheres to the surface of the spinal cord, anchoring blood vessels to it. |
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inner-most meninx, is a thin
connective tissue that adheres to the surface of the spinal cord, anchoring blood vessels to it. |
Pia mater
|
|
|
What are the denticulate ligaments?
|
The denticulate ligaments are thin extensions of the pia mater that anchor to the dura mater, effectively suspending the spinal cord within the CSF of the subarachnoid space.
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External anatomy
|
The spinal cord is roughly cylindrical and
slightly flattened in its anterior-posterior dimension. |
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The spinal cord is roughly cylindrical and
slightly flattened in its anterior-posterior dimension. |
External anatomy
|
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Differential growth
|
Early in development the spinal cord fills the
entire vertebral canal. By the time of birth, the tip of the cord reaches only to level L3-4. At age 4-5 the cord had reached its adult length and ceases to grow. This continues until adult stature is reached, is responsible for the disparity in length between the vertebral canal and the spinal cord of the adult. |
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Early in development the spinal cord fills the
entire vertebral canal. By the time of birth, the tip of the cord reaches only to level L3-4. At age 4-5 the cord had reached its adult length and ceases to grow. This continues until adult stature is reached, is responsible for the disparity in length between the vertebral canal and the spinal cord of the adult. |
Differential growth
|
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Adult length
|
when the spinal cord extends from the
foramen magnum of the occiput, where it is continuous with the medulla of the brain, to vertebral level L2. |
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when the spinal cord extends from the foramen magnum of the occiput, where it is continuous with the medulla of the brain, to vertebral level L2.
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Adult length
|
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Enlargements
|
from C4-T1, represents
the origins of spinal nerves to and from the extremities. The lumbar enlargement, from T9-T12, represents the origins of spinal nerves to and from the lower extremities. |
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from C4-T1, represents
the origins of spinal nerves to and from the extremities. The lumbar enlargement, from T9-T12, represents the origins of spinal nerves to and from the lower extremities. |
Enlargements
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Conus medullaris
|
Below the lumbar enlargement and is the conical tapering end of the adult spinal cord, ending at L2.
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Below the lumbar enlargement and is the conical tapering end of the adult spinal cord, ending at L2.
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Conus medullaris
|
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Cauda equina
|
Some nerves that arise from the spinal cord must
pass inferiorly through the vertebral canal before reaching the appropriate intervertebral foramen for exit; Wisps of nerve roots passing inferiorly through the lower vertebral canal |
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Some nerves that arise from the spinal cord must
pass inferiorly through the vertebral canal before reaching the appropriate intervertebral foramen for exit; Wisps of nerve roots passing inferiorly through the lower vertebral canal |
Cauda equina
|
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Filum terminale
|
At the tip of the conus medullaris; an extension of the pia mater that attaches inferiorly to the inside of the coccyx, thus anchoring the spinal cord within the vertebral canal.
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At the tip of the conus medullaris; an extension of the pia mater that attaches inferiorly to the inside of the coccyx, thus anchoring the spinal cord within the vertebral canal.
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Filum terminale
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Segments (#)
|
The spinal cord is functionally divided into 31
segments; from each “segment” emerges a pair of spinal nerves. Therefore, there are 31 pairs of spinal nerves: 8 cervical. 12 thoracic, 5 lumbar, 5 sacral, and 1 coccygeal. |
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The spinal cord is functionally divided into 31
segments; from each “segment” emerges a pair of spinal nerves. Therefore, there are 31 pairs of spinal nerves: 8 cervical. 12 thoracic, 5 lumbar, 5 sacral, and 1 coccygeal. |
Segments (#)
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Internal anatomy
|
In cross section, gray matter of the spinal cord
is shaped roughly like the letter “H” or a butterfly, and is surrounded by white matter. |
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In cross section, gray matter of the spinal cord
is shaped roughly like the letter “H” or a butterfly, and is surrounded by white matter. |
Internal anatomy
|
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Gray matter
|
1. Neuronal cell bodies
2. Unmyelinated axons and dendrites of association and motor neurons 3. Neuroglia |
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1. Neuronal cell bodies
2. Unmyelinated axons and dendrites of association and motor neurons 3. Neuroglia |
Gray matter
|
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White matter
|
consisting of bundles of myelinated axons of sensory, association, and motor neurons called tracts.
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consisting of bundles of myelinated axons of sensory, association, and motor neurons called tracts.
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White matter
|
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Central canal
|
The gray commissure is the cross-bar of the “H” allowing communication between the two sides and lies in the middle; runs the length of the spinal cord and communicates with the fourth ventricle of the brain.
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The gray commissure is the cross-bar of the “H” allowing communication between the two sides and lies in the middle; runs the length of the spinal cord and communicates with the fourth ventricle of the brain.
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Central canal
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Nuclei
|
The gray matter on each side of the cord is subdivided into
regions called horns. Within the gray matter are clusters of neuronal cell bodies called nuclei (centers); each nucleus has a specific function. |
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|
The gray matter on each side of the cord is subdivided into
regions called horns. Within the gray matter are clusters of neuronal cell bodies called nuclei (centers); each nucleus has a specific function. |
Nuclei
|
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Dorsal Horns
|
sections of the spinal
cord gray matter that project dorsally or posteriorly. They contain nuclei that receive sensory information from the spinal nerves and are therefore involved in sensory functions only. Axons enter here from the dorsal roots and are from those neurons whose cell bodies are located in the dorsal root ganglion found just outside the spinal ford within the intervertebral foramen. |
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sections of the spinal
cord gray matter that project dorsally or posteriorly. They contain nuclei that receive sensory information from the spinal nerves and are therefore involved in sensory functions only. Axons enter here from the dorsal roots and are from those neurons whose cell bodies are located in the dorsal root ganglion found just outside the spinal ford within the intervertebral foramen. |
Dorsal Horns
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Ventral horns
|
project ventrally or anteriorly. They contain nuclei composed of motor neurons whose axons leave the spinal cord as the ventral roots. These neurons control somatic motor functions only.
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project ventrally or anteriorly. They contain nuclei composed of motor neurons whose axons leave the spinal cord as the ventral roots. These neurons control somatic motor functions only.
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Ventral horns
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Lateral horns
|
found between the dorsal
and ventral horns and only in spinal segments T1-L2, and S2-4, contain nuclei of motor neurons. The axons of these neurons exit the spinal cord via the ventral roots. They are involved in autonomic motor functions only. |
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|
found between the dorsal
and ventral horns and only in spinal segments T1-L2, and S2-4, contain nuclei of motor neurons. The axons of these neurons exit the spinal cord via the ventral roots. They are involved in autonomic motor functions only. |
Lateral horns
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Columns
|
The white matter is also arranged into three broad
regions called columns: anterior (ventral), posterior (dorsal), and lateral. |
|
|
The white matter is also arranged into three broad
regions called columns: anterior (ventral), posterior (dorsal), and lateral. |
Columns
|
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Tracts
|
Each column is subdivided into distinct bundles of nerve
fibers, called tracts, each having a common origin or destination and carrying similar information. |
|
|
Each column is subdivided into distinct bundles of nerve
fibers, called tracts, each having a common origin or destination and carrying similar information. |
Tracts
|
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Ascending tracts
|
sensory tracts, consisting
of axons that conduct impulses, and therefore information, up the spinal cord to the brain. |
|
|
sensory tracts, consisting
of axons that conduct impulses, and therefore information, up the spinal cord to the brain. |
Ascending tracts
|
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Descending tracts
|
motor tracts, consisting
of axons that conduct impulses down the spinal cord to the ventral gray horns. |
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|
motor tracts, consisting
of axons that conduct impulses down the spinal cord to the ventral gray horns. |
Descending tracts
|
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|
The spinal cord had two essential functions:
|
1. Convey impulses between the periphery and the brain
2. Provide integrating centers for spinal reflexes |
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|
What are reflexes?
|
Reflexes are fast, predictable, autonomic responses to changes in the environment that help maintain homeostasis.
|
|
|
What are the three essential characteristics of a reflex?
|
1. Inborn
2. Unlearned 3. Unconscious |
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Roots
|
Spinal nerves are the paths of communication between the CNS and most of the periphery of the body. These are two separate points of attachment, and connect a spinal nerve with its segment of the spinal cord.
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|
Spinal nerves are the paths of communication between the CNS and most of the periphery of the body. These are two separate points of attachment, and connect a spinal nerve with its segment of the spinal cord.
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Roots
|
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Dorsal root
|
contains sensory neuron
axons that conduct impulses from the periphery into the dorsal gray horn of the spinal cord. |
|
|
contains sensory neuron
axons that conduct impulses from the periphery into the dorsal gray horn of the spinal cord. |
Dorsal root
|
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Dorsal root ganglion
|
Each dorsal root has a swelling located
within the intervertebral foramen; contains the nerve cell bodies of all the sensory neurons found in that spinal nerve. |
|
|
Each dorsal root has a swelling located
within the intervertebral foramen; contains the nerve cell bodies of all the sensory neurons found in that spinal nerve. |
Dorsal root ganglion
|
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|
Ventral root
|
contains motor neuron
axons and conducts impulses away from the spinal cord to the appropriate effectors in the periphery. The nerve cell bodies of origin for these fibers are within appropriate nuclei found either in the ventral gray horns for somatic motor effectors or in the lateral gray horns for visceral motor effectors. |
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|
contains motor neuron
axons and conducts impulses away from the spinal cord to the appropriate effectors in the periphery. The nerve cell bodies of origin for these fibers are within appropriate nuclei found either in the ventral gray horns for somatic motor effectors or in the lateral gray horns for visceral motor effectors. |
Ventral root
|
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What is a pathway?
|
The route followed by a series of nerve impulses from their origin in one part of the body to their arrival elsewhere is called a pathway. Pathways are specific neuronal circuits and may include only a single synapse (monosynaptic) or more than one synapse (polysynaptic).
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The simplest kind of pathway in the nervous system is the reflex arc. Regardless of complexity, all reflex arcs must include what five functional components?
|
1. Receptor
2. Sensory neuron 3. Center of integration 4. Motor neuron 5. Effector |
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|
Receptor
|
distal end of a sensory neuron or an
associated sensory structure that responds to a specific stimulus (change in the environment) by initiating a nerve impulse. |
|
|
distal end of a sensory neuron or an
associated sensory structure that responds to a specific stimulus (change in the environment) by initiating a nerve impulse. |
Receptor
|
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|
Sensory neuron
|
passes the nerve impulse
generated by the receptor to the axon terminals located within the gray matter of the CNS. Its cell body is located in the dorsal root ganglion. |
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|
passes the nerve impulse
generated by the receptor to the axon terminals located within the gray matter of the CNS. Its cell body is located in the dorsal root ganglion. |
Sensory neuron
|
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|
Center
|
region of the CNS gray
matter where the synapse(s) associated with the reflex are located. |
|
|
region of the CNS gray
matter where the synapse(s) associated with the reflex are located. |
Center
|
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Motor neuron
|
Impulses triggered by the integrating center are
carried by these, whose cell body lies within the gray matter, to the part of the body that will respond. |
|
|
Impulses triggered by the integrating center are
carried by these, whose cell body lies within the gray matter, to the part of the body that will respond. |
Motor neuron
|
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Effector
|
(muscle or gland) is that structure stimulated
by the motor neuron and which provides the response of the body to the change in the environment that stimulated the receptor. |
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|
(muscle or gland) is that structure stimulated
by the motor neuron and which provides the response of the body to the change in the environment that stimulated the receptor. |
Effector
|
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Brainstem
|
consists of the medulla oblongata,
pons, and midbrain. Its lower end is a continuation of the spinal cord. |
|
|
consists of the medulla oblongata,
pons, and midbrain. Its lower end is a continuation of the spinal cord. |
Brainstem
|
|
|
Diencephalon
|
sitting atop the midbrain of the
brainstem, consists primarily of the hypothalamus and the thalamus. |
|
|
sitting atop the midbrain of the
brainstem, consists primarily of the hypothalamus and the thalamus. |
Diencephalon
|
|
|
Cerebrum
|
spreads over the diencephalon like the
cap of a mushroom and occupies most of the space of the cranial vault. |
|
|
spreads over the diencephalon like the
cap of a mushroom and occupies most of the space of the cranial vault. |
Cerebrum
|
|
|
Cerebellum
|
inferior to the cerebrum and
posterior to the brainstem. |
|
|
inferior to the cerebrum and
posterior to the brainstem. |
Cerebellum
|
|
|
Dural sinus
|
The dura mater consists of an inner and an outer
portion. In certain places these layers are separated to form these large venous structures (superior sagittal, inferior sagittal, straight, and transverse (lateral) sinuses). are the routes of venous blood flow from the brain. |
|
|
The dura mater consists of an inner and an outer
portion. In certain places these layers are separated to form these large venous structures (superior sagittal, inferior sagittal, straight, and transverse (lateral) sinuses). are the routes of venous blood flow from the brain. |
Dural Sinus
|
|
|
Falx cerebri
|
A second difference is the formation of three large
sheet-like extensions of the dura that separate the larger parts of the brain; This is a large extension of the dura that extends between the two cerebral hemispheres. |
|
|
A second difference is the formation of three large
sheet-like extensions of the dura that separate the larger parts of the brain; This is a large extension of the dura that extends between the two cerebral hemispheres. |
Falx cerebri
|
|
|
Falx cerebelli
|
large extension of the dura
mater that extends between the two cerebellar hemispheres. |
|
|
large extension of the dura
mater that extends between the two cerebellar hemispheres. |
Falx cerebelli
|
|
|
Tentorium cerebelli
|
separates the
cerebral hemispheres from the cerebellar hemispheres. |
|
|
separates the
cerebral hemispheres from the cerebellar hemispheres. |
Tentorium cerebelli
|
|
|
CSF Contributes to Homeostasis 3 Ways:
|
-Mechanical Protection
-Chemical Protection -Circulation |
|
|
Mechanical protection from CSF
|
The fluid serves as a shock-absorbing
medium to prevent the brain and spinal cord from crashing against their bony surroundings. In essence, CSF “floats” the CNS within the bony chambers of the cranial vault and the vertebral canal. |
|
|
The fluid serves as a shock-absorbing
medium to prevent the brain and spinal cord from crashing against their bony surroundings. In essence, CSF “floats” the CNS within the bony chambers of the cranial vault and the vertebral canal. |
Mechanical protection from CSF
|
|
|
Chemical protection from CSF
|
CSF provides an optimal chemical environment for accurate neuronal activity; slight changes in ionic composition seriously disrupt neuronal homeostasis.
|
|
|
CSF provides an optimal chemical environment for accurate neuronal activity; slight changes in ionic composition seriously disrupt neuronal homeostasis.
|
Chemical protection from CSF
|
|
|
Circulation from CSF
|
CSF is a medium for exchange of nutrients and
wastes between the blood and the nervous tissue |
|
|
CSF is a medium for exchange of nutrients and
wastes between the blood and the nervous tissue |
Circulation from CSF
|
|
|
Medulla Oblongata
|
Gray matter: nuclei for immediate survival: blood pressure, heart rate, respiration, swallowing, coughing, vomiting, etc.
White matter: all ascending & descending tracts that communicate between the brain and spinal cord. Cranial nerves: found in the medulla gray matter are the motor nuclei for cranial nerves XII, XI, X, IX, and part of VIII. The sensory neuron cell bodies for these cranial nerves are located outside the medulla in various ganglia. |
|
|
Pons
|
Gray matter: two nuclei involved in the alteration of basic respiratory pattern.
White matter:tracts pass between lower and higher CNS structures, as well as communicating the cerebellum with the rest of the CNS. Cranial nerves -- In addition to the centers, the motor nuclei of cranial nerves part of VIII, VII, VI, and V are also located in the pontine gray matter. The sensory neuronal cell bodies are located in ganglia outside the pons. |
|
|
Gray matter: two nuclei involved in the alteration of basic respiratory pattern.
White matter:tracts pass between lower and higher CNS structures, as well as communicating the cerebellum with the rest of the CNS. Cranial nerves -- In addition to the centers, the motor nuclei of cranial nerves part of VIII, VII, VI, and V are also located in the pontine gray matter. The sensory neuronal cell bodies are located in ganglia outside the pons. |
Pons
|
|
|
Gray matter: nuclei for immediate survival: blood pressure, heart rate, respiration, swallowing, coughing, vomiting, etc.
White matter: all ascending & descending tracts that communicate between the brain and spinal cord. Cranial nerves: found in the medulla gray matter are the motor nuclei for cranial nerves XII, XI, X, IX, and part of VIII. The sensory neuron cell bodies for these cranial nerves are located outside the medulla in various ganglia. |
Medulla Oblongata
|
|
|
Midbrain
|
Dorsal portion: [tectum (roof)] divided into 4 rounded of gray matter called corpus quadrigemina.
-2 superior colliculi -2 inferior colliculi Ventral portion: all white matter, w/2 groups of fiber tracts: cerebral peduncles and medial lemniscus. Cranial nerves: in the tectum are the motor neurons for cranial nerves IV and III; the sensory neuron cell bodies associated with these cranial nerves are located in the ganglia outside the midbrain |
|
|
superior colliculi
|
reflex movements of the eyes, head, and neck in response to visual and other stimuli.
|
|
|
Dorsal portion: [tectum (roof)] divided into 4 rounded of gray matter called corpus quadrigemina.
-2 superior colliculi -2 inferior colliculi Ventral portion: all white matter, w/2 groups of fiber tracts: cerebral peduncles and medial lemniscus. Cranial nerves: in the tectum are the motor neurons for cranial nerves IV and III; the sensory neuron cell bodies associated with these cranial nerves are located in the ganglia outside the midbrain |
Midbrain
|
|
|
control reflex movements of the eyes, head, and neck in response to visual and other stimuli.
|
superior colliculi
|
|
|
2 inferior colliculi
|
reflex movements of the head and trunk in response to auditory stimuli).
|
|
|
control reflex movements of the head and trunk in response to auditory stimuli).
|
2 inferior colliculi
|
|
|
cerebral peduncles
|
pass motor fibers from the cerebrum through the brain stem. They also carry some sensory information passing to the cerebrum from the spinal cord.
|
|
|
pass motor fibers from the cerebrum through the brain stem. They also carry some sensory information passing to the cerebrum from the spinal cord.
|
cerebral peduncles
|
|
|
medial lemniscus
|
band of sensory fiber tracts passing from the lower CNS to the thalamus; carries impulses for discriminative touch, proprioception, pressure, and vibrations.
|
|
|
band of sensory fiber tracts passing from the lower CNS to the thalamus; carries impulses for discriminative touch, proprioception, pressure, and vibrations.
|
medial lemniscus
|
|
|
Thalamus
|
-(“inner chamber”) is an oval structure above the midbrain, forming 4/5 of the diencephalon
-consists of paired masses of gray matter organized into nuclei that form the lateral walls of the third ventricle. -principal relay station for sensory impulses, except smell, that reach the cerebral cortex from the spinal cord, brain stem, and other parts of the cerebrum |
|
|
-(“inner chamber”) is an oval structure above the midbrain, forming 4/5 of the diencephalon
-consists of paired masses of gray matter organized into nuclei that form the lateral walls of the third ventricle. -principal relay station for sensory impulses, except smell, that reach the cerebral cortex from the spinal cord, brain stem, and other parts of the cerebrum |
Thalamus
|
|
|
Hypothalamus
|
-small portion of the diencephalon (about 1/5) lying below the thalamus.
-primarily gray matter dividing into pairs of nuclei. -one of the major controllers of homeostasis |
|
|
-small portion of the diencephalon (about 1/5) lying below the thalamus.
-primarily gray matter dividing into pairs of nuclei. -one of the major controllers of homeostasis |
Hypothalamus
|
|
|
CEREBRUM
|
Cortex: The surface composed of gray matter
White matter: Beneath the cerebral cortex is the cerebral white matter consisting of axons; internal capsule. Function: intelligence, consciousness, and 5 senses -Gyrus/sulcus Fissures: 3; longitudinal fissure, the lateral fissure, lying between the temporal and parietal lobes, and the transverse fissure, between the cerebrum and the cerebellum. Corpus callosum large bundle of whiter matter connecting hemispheres |
|
|
Cortex: The surface composed of gray matter
White matter: Beneath the cerebral cortex is the cerebral white matter consisting of axons; internal capsule. Function: intelligence, consciousness, and 5 senses -Gyrus/sulcus Fissures: 3; longitudinal fissure, the lateral fissure, lying between the temporal and parietal lobes, and the transverse fissure, between the cerebrum and the cerebellum. Corpus callosum large bundle of whiter matter connecting hemispheres |
CEREBRUM
|
|
|
What is the insula?
|
A fifth portion of the cerebrum, the insula, cannot be seen from the exterior of the cerebrum. It lies deep within the lateral fissure, under the parietal, temporal, and frontal lobes.
|
|
|
Association
|
fibers that transmit impulses between the gyri of one hemisphere, associating information between different inputs and outputs.
|
|
|
fibers transmit impulses between
the gyri of one hemisphere, associating information between different inputs and outputs. |
Association white matter
|
|
|
Commissural white matter
|
fibers that transmit impulses from the gyri one of the hemispheres to the gyri of the other hemisphere, passing through either the corpus callosum, the anterior commissure, or the posterior commissure.
|
|
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fibers that transmit impulses from the gyri one of the hemispheres to the gyri of the other hemisphere, passing through either the corpus callosum, the anterior commissure, or the posterior commissure.
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Commissural white matter
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Projection white matter
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fibers that form descending or ascending tracts that communicate the cerebral cortex with the spinal cord and other lower brain structures.
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fibers that form descending or ascending tracts that communicate the cerebral cortex with the spinal cord and other lower brain structures.
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Projection white matter
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What are the basal ganglia?
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consist of several groups of paired nuclei found within the white matter of the cerebrum. The nuclei are interconnected by many nerve fibers with each other, and receive numerous inputs from the cerebral cortex, thalamus, and hypothalamus.
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Basal ganglia functions?
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The basal ganglia function in the control of large, learned, semi-voluntary skeletal muscle movements, such as swinging the arms when walking, laughing, etc., and in the regulation of muscle tone.
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What is the limbic system?
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a ring of structures surrounding the inner border of the cerebrum and the floor of the diencephalon, encircling the midbrain. It is formed by gyri of the insular lobe, nuclei associated with the basal ganglia, hypothalamus, and the thalamus, the olfactory bulbs, and bundles of interconnecting white matter.
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What is the limbic system's function?
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often called the emotional brain, functions in emotional aspects of behavior related to survival, memory, smell, pleasure and pain, rage and aggression, docility and tameness, affections, sexual desire, etc.
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What are the functional areas of the cerebral cortex?
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Specific types of sensory, motor, and integrative signals are processed in specific regions of the cerebral cortex called functional areas. In general, the areas are divided into three types: primary sensory, primary motor, and association.
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Sensory areas of Cerebral Cortex
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receive sensory input, and
integrate and interpret the sensations. There are at least 20 different specific areas for each of the individual modalities. |
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receive sensory input, and
integrate and interpret the sensations. There are at least 20 different specific areas for each of the individual modalities. |
Sensory areas of Cerebral Cortex
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Motor areas of Cerebral Cortex
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contain the neuronal cell bodies of origin for practically all motor activities. They are divided into at least 5 different areas associated with muscular activity.
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contain the neuronal cell bodies of origin for practically all motor activities. They are divided into at least 5 different areas associated with muscular activity.
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Motor Areas of Cerebral Cortex
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Association areas of Cerebral Cortex
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make up several
main areas that serve to connect the sensory and motor areas. They provide integrative and interpretive functions, such as memory, emotion, relationships between sensations, etc. |
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make up several
main areas that serve to connect the sensory and motor areas. They provide integrative and interpretive functions, such as memory, emotion, relationships between sensations, etc. |
Association areas of Cerebral Cortex
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Midbrain Cranial Nerves
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III, IV, V
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Pons Cranial Nerves
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VI, VII
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Medulla Cranial Nerves
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IX, X, XI, XII
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