CH # 9: Nervous System Flashcards
A nerve impulse
A rapid change in membrane potential that involves depolarization and repolarization
Action potential
2 names 4 the part of a neuron that carries impulses away from cell bodies
This structure is surrounded by many myelinated segments, while the unmyelinated regions between the segments r called the nodes of Ranvier
Axons
Efferent processes
Paired regions of grey matter scattered through out the white matter of the cerebrum
Functions as a relay station, or areas of synapse, in pathways going 2 and from the cortex.
They decrease muscle tone and inhibit musclar activity and play an important role in maintaining posture and coordinating motor movements
Almost all of a persons dopamine is produced here
Basal ganglia
The portion of the brain, between the diencephalon and spinal chord, that contains the midbrain, pons and medulla oblongata
Top down: midbrain > pons > medulla oblongata
Controls 3 vital centers of visceral activities:
- cardiac center; adjusts heart rate and contraction strength
- vasomotor center; regulates blood pressure
- respiratory center; regulates rate, rhythm and depth of breathing
Brain stem
2 names 4 the grove of furrow between the frontal and parietal lobes of the cerebrum
Central sulcus
Fissure of Rolando
2nd largest part of the human brain, located posterior 2 the pons and medulla oblongata and involved in the coordination of muscular movements
Cerebellum
A fluid, similar 2 plasm, that fills the subarachnoid space around the brain and spinal cord
Located in the ventricles of the brain
Cerebrospinal fluid
The largest and uppermost part of the human brain
Concerned w/consciousness, learning, memory, sensations and voluntary movements
Cerebrum
2 names 4 the branching (treelike) structures of a neuron that receive impulses from other neurons and transmit them 2 the cell body
The number of “branches” varies w/each neuron
Dendrites
Afferent processes
A crossing over
Usually refers 2 motor fibers that cross over 2 the opposite side in the medulla oblongata
Decussation
Part of the brain between cerebral hemispheres and the midbrain
Includes the thalamus and hypothalamus
Diencephalon
White, fatty substances that surrounds many nerve fibers
CNS: produced by oligodendrocytes but NO neurilemma meaning
no regeneration of fibers possible
PNS: produced by Schwann cells 2 form the neurilemma
Myelin
2 names 4 the layer of cells that surrounds a nerve fiber in the PNS and in some cases produces myelin
Neurilemma
Schwann sheath
Supporting cells of nervous tissue
Cells in nervous tissue that do not conduct impulses
Neuroglia
Nerve cell including its processes which includes:
-cell body/soma; nucleus,1 or more nucleolus, cytoplasmic
organelles
-dendrite(s) cytoplasmic extensions/fibers from the cell body
-1 axon; process that projects from the cell body
Conducting cell of nervous tissue that relays impulses
Amitotic: new structures can NOT be made or replaced
Neuron
A chemical substance that is released from the axon terminals 2 stimulate muscle fiber contraction or an impulse in another neuron
Neurotransmitters
Short spaces between segments of myelin in a myelinated nerve fiber
Nodes of Ranvier
Time during which an excitable cell cannot respond 2 a stimulus that is usually adequate 2 initiate an action potential
Refractory peroid
Process in which a nerve impulse travels along a myelinated nerve fiber by jumping from 1 node of Ranvier 2 the next
Saltatory conduction
The primary motor area of the brain
Located in the precentral gyrus
Transmits motor impulses 2 the body
Somatomotor cortex
The primary sensory area of the brain
Located in the postcentral gryus
Receives sensory impulses from the body
Somatosensory cortex
The region of communication between 2 neurons
Synapse
2 names 4 a minimum level of stimulation that is required 2 start a nerve impulse or muscle contraction
Threshold stimulus
Liminal stimulus
Part of the nervous system that includes the brain and the spinal cord in the dorsal cavity, both encased in bone 4 protection:
- Brain is in the the cranial vault
- Spinal cord is in the vertebral canal of the vertebral column
Surrounded by connective tissue membranes called meninges and cerebral spinal fluid
Central Nervous System
CNS
Connective tissue membranes that surround the CNS
Consists of 3 layers:
- dura mater; outer layer
- arachnoid; middle layer
- pia mater; inner layer
Meninges
The outer layer of meninges that surround the brain and spinal cord
Tough, white, connective tissue that is just inside the cranial bones and lines the vertebral canal
Contains channels called dural sinuses which collect venous blood 2 return 2 the cardiovascular system
Dura Mater
The middle layer of meninges that surround the brain and spinal cord
Resembles a cob web in appearance because it has numerous threadlike strands that attach it 2 the inner most layer
There is a sub space beneath it that is filled w/CSF and contains blood vessels
Arachnoid
The sub space beneath the middle layer of the meninges that surround the brain that is filled w/CSF and contains blood vessels
Subarachnoid Space
The inner layer of meninges that surround the brain and spinal cord
Thin, delicate membrane that is tightly bound 2 the surface of the brain and spinal cord
Pia Mater
1 part of the CNS
Divided in2 4 parts:
- cerebrum
- diencephalon
- brain stem
- cerebellum
Brain
Afferent neuron
Cell body is in the ganglion outside the CNS and extends in2 the CNS
Function is 2 transmit nerve impulses from receptor 2 CNS
Sensory neuron
The largest portion of the brain
Divided in2 2 cerebral hemispheres by a deep longitudinal fissure but it is connected by an arching band of white fibers called the corpus callosum. The corpus callosum functions as a communication pathway between the hemispheres
Each hemisphere is divided in2 5 lobes:
- frontal lobe
- parietal lobe
- occipital lobe
- temporal lobe
- insula/island of Reil
Cerebrum
Grey matter that forms the outermost part of the cerebrum
Consists of neuron cell bodies and UNmyelinated fibers
The center 4 sensory and motor functions:
- somatosensory cortex
- somatomotor cortex
Cerebral cortex
A region of the cerebral cortex located in the post central gyrus of the parietal lobe
This area of the brain is the primary sensory area that receives information from various sense organs and receptors throughout the skin and skeletal muscles
Right side receives input from the left side of the body and vice versa
Somatosensory Cortex
A region of the cerebral cortex in the precentral gyrus in the frontal lobe
Area responsible 4 muscle contraction allowing us 2 have conscious control of our skeletal muscles
The right side controls the left side of the body and vice versa
Highly organized in a way similar 2 the primary sensory cortex w/neurons in a specific region responsible 4 controlling movement in a specific part of the body
Somatomotor Cortex
The connective tissue membranes that surround the brain and spinal cord r the?
Meninges
The outer layer is the?
Dura mater
The middle layer is called?
Arachnoid
Innermost layer is called the?
Pia mater
The _________ mater adheres 2 brain tissue and the spinal cord
Pia
The largest [part of the brain is the?
Cerebrum
The _____________ _____________divides the cerebrum in2 2 cerebral hemispheres
Longitudinal fissure
The band of white fibers that connects the cerebral hemispheres is the?
Corpus callosum
The convolutions the surface of the cerebrum r called?
Gyri
The grooves that separate gyri r called?
Sulci
The 4 of the lobes and the bones of the skull have the same?
Name
The outermost portion of the cerebrum that consists of grey matter is called?
Cerebral cortex
Motor speech is controlled primarily by ______________ area in the frontal lobe?
Broca’s
The understanding of language is primarily located in ________ area of the temporal lobe?
Wernicke’s
____________ matter forms communication pathways
White
The thalamus, hypothalamus epithalamus collectively make up the?
Diencephalon
The ____________ is the largest part of the diencephalon?
Thalamus
The ___________ serves as a connection between the CNS and the endocrine system
Hypothalamus
The most superior part of the brain stem is the?
Midbrain
The middle portion of the brain stem is the?
Pons
Pons means?
Bridge
The inferior part of the brain stem is the?
Medulla oblongata
The 2nd largest portion of the brain is the?
Cerebellum
The fluid-filled cavities in the brain that r interconnected r?
Ventricles
____________________ fluid is produced in the lateral ventricles and circulates through the 3rd and 4th ventricles 2 the cerebral aqueduct and the central canal of the spinal cord and throughout the subarachnoid layer of the meninges
Cerebrospinal
The nervous system helps 2 maintain hemostasis by regulating vital functions and responding 2 internal and?
External stimuli
Information that is gathered from stimuli, converted 2 nerve impulses and transmitted 2 the brain is reffered 2 as?
Sensory input
Nervous system responds 2 sensory input and integration and sends signals 2 effectors, this is referred 2 as?
Motor functions
Motor signal travel ___________ from the brain
Away
The CNS and PNS r the 2 subdivisions of the?
Nervous system
What r the 2 organs of the CNS?
Brain and spinal cord
Which of these organs have more parts?
brain or spinal cord
Brain
Bundles of nerve fibers that extend from the CNS 2 the peripheral organs r called?
Nerves
Collections of nerve cell bodies outside the CNS r called?
Ganglia
The PNS is subdivided in2 ____________ and ___________ divisions
Afferent
and
Efferent
______________ divisions transmits impulses from periphral organs 2 the CNS?
Sensory
or
Afferent
______________ divisions transmits impulses from the CNS 2 peripheral organs
Efferent
The prefix ad- means
Toward
The prefix ex- means
Away
The somatic nervous system is under ____________ control?
Voluntary
Somatic literally means
Related 2 body structures
R impulses 2 skeletal muscles afferent impulses or efferent impulses?
Efferent
Autonomic nervous system is under ______________ control
Involuntary
ANS is further subdivided in2 ___________ and __________ divisions
Sympathetic
Parasympathetic
The _________________ nervous system supplies motor impulses 2 cardiac muscle, smooth muscle and glandular epithelium
Autonomic
What r the 2 divisions of the efferent division of the PNS?
Somatic
and
Autonomic
R efferent impulses motor or sensory?
Motor
What r the 2 divisions of the afferent division of the PNS?
Visceral
and
Somatic
R afferent impulses motor or sensory?
Sensory
A nerve cell is called?
Neuron
The cell that provides a support system 4 neurons is called?
Neuroglia
The suffix -glia means?
Glue
Neurons do not under go mitosis, the term 4 this is?
Amitotic
The main part of the neuron that contains the nucleus is the?
Cell body
The cytoplasmic extensions that r short and branching and transmit impulses 2 the cell body is the?
Dendrites
The cytoplasmic extension that is elongated that carries impulses away from the cell body is called the?
Axon
The enlargement at the distal end of the telodendria that contains vesicles of neurotransmitters is the?
Synaptic knob
White fatty substance that surrounds nerve fibers is called?
Myelin
Short, unmyelinated regions between 2 segments of myelin in myelinated nerve fiber is called?
Nodes of Ranvier
__________ form the connecting link between the afferent and efferent neurons
Interneurons
A series of fluid-filled (cerebrospinal fluid)cavities found w/in the brain
Ventricles
Cranial nerves associated w/the special senses of smell, vision, hearing and equilibrium and have only sensory fibers
Cranial nerves I, II, VIII
Cranial nerves that r primarily motor in function but does have some sensory fibers 4 proprioception
Cranial nerves III, IV, VI, XI, XIII
Cranial nerves consist of significant amounts of both sensory and motor fibers
Cranial nerves V, VII, IX, X
31 pairs of (mixed)nerves emerge laterally from the spinal cord
Each is connected 2 the spinal cord by 2 types of roots:
- dorsal root; sensory only
- ventral root; motor only
Spinal nerves
Spinal nerves C1 - C8
Cervical nerves
Spinal nerves T1 - T12
Thoracic nerves
Spinal nerves L1 - L5
Lumbar nerves
Spinal nerves S1 - S5
Sacral nerves
Spinal nerve Co
Coccygeal nerve
An autonomic involuntary response 2 some change, either inside or outside the body
Reflex
