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54 Cards in this Set
- Front
- Back
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Absolute refractory period
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a. Time during which a second stimulus cannot produce an action potential
b. Voltage-gated Na+ channels already open or are inactivated |
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WHAT DO THE MENINGES COVER?
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THE ENTIRE CNS.
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Axons
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long thin process, send impulse
1. Originates on axon hillock of soma, initial segment contains trigger zone, with neurofilaments for transport 2. Axon collaterals - side branches 3. Terminates in many fine filaments or axon terminals with synaptic knobs containing synaptic vesicles |
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WHERE DOES THE SPINAL CORD END?
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L2
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Schwann cells
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produce myelin sheath around axons of PNS neurons.
Schwann cell membrane wraps around the axon many times; nucleus & cytoplasm form outermost layer or neurolemma which provides regeneration tube. Nodes are uncovered areas between Schwann cells. |
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A SKULL FRACTURE MAY LACERATE WHICH ARTERY?
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THE MIDDLE MENINGEAL ARTERY, LOCATED IN THE EPIDURAL SPACE.
THIS IS A LIFE THREATENING PROBLEM. |
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Continuous propagation
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Continuous propagation - action potential moves in series of small steps along the unmyelinated axon
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PERIPHERAL NERVOUS SYSTEM IS COMPRISED OF
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PERIPHERAL RECEPTOR ORGANS
SPINAL NERVES PERIPHERAL NERVES GANGLIA |
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WHAT ARE THE LAYERS OF THE MENINGES?
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DURA
ARACHNOID PIA |
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Saltatory propagation
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action potential jumps from node to node along the myelinated axon, 5-7X faster, uses less ATP energy
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WHERE IS THE EPIDURAL SPACE?
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BETWEEN THE SKULL AND THE DURA MATTER.
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Neurons
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converts stimuli into nerve impulses (excitability), limited mitosis
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WHAT IS THE TENTORIUM CEREBELLI?
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A HORIZONTAL REFLECTION OF THE DURA BETWEEN THE OCCIPITAL LOBE OF THE CEREBRUM AND THE CEREBELLUM.
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Relative refractory period
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a. Time during which only a second very strong stimulus produces an action potential
b. Voltage-gated Na+ channels are closed but no longer inactivated T0 = resting membrane pot T1 = depolarized T2 = reverse polarity T3 = repolarized T4 = hyperpolarized Red = absolute refractory period (see physiology text) Green = relative refractory period (see physiology text) |
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HOW MUCH DOES THE BRAIN AND SPINAL CORD WEIGH?
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1400 GRAMS
MALE BRAIN IS HEAVIER THAN FEMALE. |
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Soma
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cell body with typical plasma membrane & cell organelles.
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WHAT IS THE FALX CEREBELLI?
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INCOMPLETELY SEPARATES THE CEREBELLAR HEMISPHERES.
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Dendrites
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highly branched generally short cytoplasmic processes, receive input
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WHAT ARE THE TWO LAYERS OF THE DURA.
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PERIOSTEAL LAYER -ALONG THE SKULL.
INNER MENINGEAL LAYER. |
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Neurons classified by number of processes:
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1. Unipolar - one bifurcated process, dendrites & axon are continuous, sensory neurons
2. Bipolar - two processes, one dendritic & one axonic, special senses neurons 3. Multipolar - more than two processes, one axon & several dendrites, motor neurons |
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WHAT ARE THE PARTS OF THE DIENCEPHALON?
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THALAMUS
HYPOTHALAMUS EPITHALAMUS SUBTHALAMUS |
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Axon diameter
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larger diameter axons conduct faster than smaller diameter axons
Type A fibers: 4-20 mm axon diameter, myelinated, 12-140 m/ sec Type B fibers: 2-4 mm axon diameter, myelinated, 12-18 m/sec Type C fibers: less than 2 mm axon diameter, unmyelinated, 0.5-2 m/sec |
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WHAT DO YOU CALL A BUNDLE OF AXONS IN THE CNS?
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TRACT
FASCICULUS PEDUNCLE LEMNISCUS |
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Myelinated axons
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have a thick myelin sheath composed of lipid & protein (myelin), acts as insulating layer.
myelinated axons conduct faster than unmyelinated axons |
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WHAT IS THE FALX CEREBRI?
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IT'S A VERTICAL REFLECTION OF THE DURA BETWEEN THE CEREBRAL HEMISPHERES.
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Unmyelinated axons
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covered by a thin layer of glial plasma membrane
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BRAINSTEM
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MESCENCEPHALON (MIDBRAIN)
PONS & MEDULLA |
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Satellite cells
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Neuroglial cell that surround & support ganglionic cells in PNS
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WHICH SPINAL NERVES HAVE NO CORRESPONDING VERTEBRAE.
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C8
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Microglia
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form from monocytes, phagocytic cells (microbes & debris) in CNS
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HOW DOES THE DURA PROVIDE SUPPORT AND COVERAGE FOR THE BRAIN?
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FALIX CEREBRI
TENTORIUM CEREBELLI FALIX CEREBELLI |
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Ependyma
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Neuroglia cell - line CSF-filled cavities of CNS & filter CSF.
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FOUR LOBES OF THE CEREBRUM
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FRONTAL
PARIETAL TEMPORAL OCCIPITAL |
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oligodendrocytes
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most common neuroglial cell, produce myelin sheath around axons in CNS
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WHERE IS THE CIRCLE OF WILLIS LOCATED?
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VENTRAL ASPECT OF THE BRAIN
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ARACHNOID LAYER
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AVASCULAR, EXTERNAL MESOTHELIUM.
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CENTRAL NERVOUS SYSTEM IS COMPRISED OF
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BRAIN
SPINAL CORD |
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Astrocytes
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star shaped, in CNS, maintain K+ balance, link neurons & vessels forming blood-brain barrier.
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THE CAUDA EQUINA IS WHAT PART OF THE SPINAL CORD?
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L2-L5
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WHERE IS THE SUBARACHNOID SPACE?
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SPACE BETWEEN THE ARACHNOID PIA LAYER.
CONTAIN CSF, CEREBRAL VESSELS,ARACHNOID GRANULATION. SITE OF HEMORRHAGE - ANEURYSM,CIRCLE OF WILLIS. |
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AUTOMONIC NERVOUS SYSTEM
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REGULATION OF VISCERAL FUNCTION.
PART OF CNS AND PNS |
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WHERE DO THE 2 MOST COMMON ANEURYSMS IN THE CIRCLE OF WILLIS OCCUR?
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ANTERIOR COMMUNICATING ARTERY.
POSTERIOR COMMUNICATING ARTERY. |
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WHAT IS LOCATED BETWEEN THE TWO LAYERS OF THE DURA?
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VENOUS CHANNELS CALLED SINUSES.
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Neuroglial cells.
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do not generate or conduct impulses; support, nurture & protect neurons, smaller, more numerous, mitotic.
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WHAT ARE THE PARTS OF THE BASAL GANGLIA?
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CAUDATE NUCLEUS
GLOBUS PALLIDUS CLAUSTRUM PUTAMEN AMYGLADA |
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WHERE IS THE SUBDURAL SPACE?
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SPACE BETWEEN THE DURA AND ARACHNOID.
TRAUMA TO THE BRIDGING VEINS CAN CAUSE TRAUMA AND HEMATOMA. |
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WHAT IS THE FUNCTIONAL UNIT OF THE CNS?
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NEURON- CELL BODY
AXON DENDRITE SYNAPSE- DENDRITE-AFFERRENT AXON-EFFERENT |
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PIA LAYER
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THIN AND VASCULAR
HUGS THE BRAIN. |
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WHAT ARE THE TWO TYPES OF GOLGI NEURONS IN THE CNS?
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GOLGI TYPE I - EXCITATORY
GOLGI TYPE II - INHIBATORY |
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HOW MANY PAIRS OF SPINAL NERVES?
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31
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WHAT IS BETWEEN THE CEREBRUM & BRAINSTEM?
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DIENCEPHALON AND BASAL GANGLIA.
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WHAT DO YOU CALL A CHAIN OF COMMUNICATING NEURONS IN THE CNS.
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PATHWAY
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WHAT PROTECTS THE CNS?
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SKULL
VERTEBRAE MENINGES |
