Ch. 12 Neural Tissue
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121 terms
Terms | Definitions |
|---|---|
 2 kinds of cells in Nerve tissue: | neurons, neuroglia |
| Cells that send and receive signals: | Neurons, also the function unit of nerve cells. |
| Neuroglia: | cells that support and protect neurons |
| 2 Divisions of Nervous System: | CNS- brain & spinal cord, used to process and coordinate act. in the body; PNS- all neural tissue outside CNS |
| Functions of CNS: | Used to process & coordinate activities in the body |
| Functions of PNS: | Deliver sensory information to the CNS, and gets message back of what to do. |
| Cranial nerves connect to the: | brain (12 cranial nerves) |
| Spinal nerves attach to the: | spinal cord (31 spinal nerves) |
| Functional Divisions of PNS: | afferent, efferent |
| Afferent: | (TO) Carries sensory information from PNS sensory receptors TO CNS |
| The primary function(s) of the nervous system include: | providing sensation to the internal & external environments, integrating sensory info, & regulating and controlling peripheral structures & systems |
| Neurons are responsible for: | information transfer and processing in the nervous system |
| The region of a neuron with voltage-gated sodium channels is the: | axon hillock |
| Neurons are classified on the basis of their structure as: | motor, sensory, association |
| The two major cell populations of neural tissue are: | neurons and neuroglia |
| CNS glial cell that removes debris, wastes, and pathogens by phagocytosis: | microglia |
| The white matter of the CNS represents a region dominated by the presence of: | oligodendrocytes |
| Depolarization of the membrane will shift the membrane potential toward: | 0 mV |
| What is the term given to describe a shift in transmembrane potential from -70 mV to -90 mV? | hyperpolarization |
| If resting membrane potential is -70 mV and the threshold is -60 mV, a membrane potential of -62 mV will: | not produce an action potential |
| At the site of an action potential, the membrane contains: | an excess of positive ions inside and an excess of negative ions outside |
| A node along the axon represents an area where there is | an absence of myelin |
| Nerve cell bodies in the PNS are clustered together in masses called: | ganglia |
| The most important factors that determine the rate of action potential conduction are: | the presence or absence of a myelin sheath and the diameter of the axon |
| At an electrical synapse, the presynaptic and postsynaptic membranes are locked together at: | gap junctions |
| Exocytosis and the release of acetylcholine into the synaptic cleft is triggered by: | calcium ions flooding into the axoplasm |
| Inhibitory or hyperpolarizing CNS neurotransmitters include: | dopamine and serotonin |
| An excitatory postsynaptic potential (EPSP) is: | a depolarization produced by the arrival of a neurotransmitter |
| An inhibitory postsynaptic potential (IPSP) is a: | transient hyperpolarization of the postsynaptic membrane |
| Sensory neurons are responsible for carrying impulses: | to the CNS |
| Interneurons, or associated neurons, differ from sensory and motor neurons because of their: | exclusive location in the brain and spinal cord |
| Efferent pathways consist of axons that carry impulses: | away from the CNS |
| Graded potentials that develop on the postsynaptic membrane in response to a neurotransmitter are: | postsynaptic potentials |
| The addition of stimuli occurring in rapid succession is: | temporal summation |
| When sensory information is relayed from one processing center to another in the brain, the pattern is called | serial processing |
| Interneurons are responsible for: | analysis of sensory inputs and coordination of motor outputs |
| Sensory (ascending) pathways distribute information | from peripheral receptors to processing centers in the brain |
| Schwann cells are glial cells responsible for: | producing a complete neurilemma around peripheral axons |
| When a barrier prevents the movement of opposite charges toward one another, a(n) | potential difference exists |
| The sodium-potassium pump's activity is needed after: | every action potential to restore resting potential |
| All-or-nothing principle: | A given stimulus either triggers a typical action potential or does not produce one at all |
| During the relative refractory period, a larger-than-normal depolarizing stimulus can: | bring the membrane to threshold and initiate a second action potential |
| Saltatory conduction conducts impulses along an axon | five to seven times faster than continuous conduction |
| In type C fibers action potentials are conducted at speeds of approximately | 2 mph |
| The larger the diameter of the axon, the | faster the rate of transmission |
| dipping toe in cold water, pulling back.. The sensory neurons responsible for this is: | exteroceptors |
| The main functional difference between the autonomic nervous system and the somatic nervous system is that the activities of the ANS are | primarily involuntary or under "automatic" control |
| Reverberation in neural circuits refers to collateral axons that: | use positive feedback to simulate presynaptic neurons |
| What is happening during a "runners high"? | Endorphins are blocking the transmission of substance P, a neurotransmitter that sends information about pain to the CNS |
| The most excitatory neurotransmitter in the brain and functions in learning and memory: | glutamate |
| What are the two major ions that are involved in generating an action potential? | sodium and potassium. These ions determine the gradient that drives the depolarization of the membrane. |
| What do we call the difference in charge between the inside of the nerve cell membrane and the outside? | the membrane potential. The difference in charge between the inside and outside of the membrane gives the membrane its responsive nature. |
| What is the first thing needed to start an action potential? | a stimulus. In order for an action potential to be produced, there has to be a stimulus great enough to start the cascade effect down the axon. |
| What ion initiates the formation of vesicles filled with acetylcholine? | calcium. As the axon potential arrives at the synaptic terminal, calcium channels open and with calcium influx, the formation of vesicles begins. |
| When the membrane potential is disturbed, which ion enters the cell? | sodium. When the stimulus causes a disruption in the cell membrane, sodium rushes into the cell. |
| What do we call the change in the sodium and potassium ions caused by a stimulus? | depolarization. When sodium rushes in, it causes a change in the membrane potential that starts the message down the axon. |
| When there is no stimulus to the nerve cell, is the cell said to be.. | at rest. Homeostasis refers to the body's maintenance of a stable internal environment. |
| How is potassium recaptured after depolarization? | sodium-potassium pumps. The pumps are responsible for reclaiming the ions so the cell can respond again. |
| The space between nerve cells is called the | synapse |
| What is the ion responsible for initiating the formation of acetylcholine? | Calcium |
| What are the chemicals called that propagate the message across the synapse? | neurotransmitters |
| What is the most abundant neurotransmitter in the body | acetylcholine. |
| The part of the cell that receives the impulse is called | the dendrite |
| glial cells that surround cell bodies in the PNS and regulates levels of oxygen and carbon dioxide around ganglionic neurons: | satellite cells |
| glial cells that can form a myelin sheath around axon fibers in the central nervous system: | oligodendrocyte |
| The binding of ACh on the axon hillock triggers | the opening of voltage-gated channels. |
| Synaptic delay is greater at synapses of.. | myelinated neurons than at those of unmyelinated neurons. |
| A chemical synapse at which the neurotransmitter is acetylcholine is called | cholinergic synapse |
| Receptors of afferent division: | detect changes or respond to stimuli |
| Effectors of afferent division: | respond to efferent (taking signals away from brain and bringing back to PNS) signals |
| Somatic nervous system (SNS): | controls skeletal muscle contractions: voluntary and involuntary (reflexes) muscle contractions |
| Autonomic nervous system (ANS): | controls subconscious actions: contractions of smooth muscle and cardiac muscle and glandular secretions |
| sympathetic division: | has a stimulating effect (speeds), adrenaline rush |
| parasympathetic division: | has a relaxing effect (slows), when stuck with needle, get a vegas response due to vegas nerve. |
| ___ perform all of the communication, information processing, and control functions of the nervous system. | neurons |
| multipolar neuron | Common in the CNS: cell body (soma) short, branched dendrites long, single axon (tail) |
| Perikaryon | (cytoplasm) |
| RER and ribosomes produce.. | neurotransmitters |
| Neurofibrils: | bundles of neurofilaments that provide support for dendrites and axon |
| Nissl Bodies: | Dense areas of RER and ribosomes Make neural tissue appear gray (gray matter, not mylenated; slower) |
| Dendrites: | look like little fingers |
| Dendritic spines: | many fine processes receive information from other neurons 80-90% of neuron surface area |
| The axon | (long tail) Carries electrical signal (action potential) to target, Axon structure is critical to function |
| Axoplasm | Cytoplasm of axon Contains neurotubules, neurofibrils, enzymes, organelles |
| Axolemma | Specialized cell membrane Covers the axoplasm |
| Axon hillock | where tail attaches to cell body, Thick section of cell body Attaches to initial segment |
| Telodendria | Fine extensions of distal axon |
| Synaptic terminals | Tips of telodendria |
| Synapse: | (gap in neuron connection) Area where a neuron communicates with another cell |
| The synapse steps: | Presynaptic cell, Postsynaptic cell, The synaptic cleft |
| Presynaptic cell | neuron that sends message |
| Postsynaptic cell: | cell that receives message |
| The synaptic cleft: | the small GAP that separates the presynaptic membrane and the postsynaptic membrane |
| The synaptic knob | Is expanded area of axon of presynaptic neuron, Contains synaptic vesicles of neurotransmitters |
| Neurotransmitters | are chemical messengers, released at presynaptic membrane, affect receptors of postsynaptic membrane, are broken down by enzymes, are reassembled at synaptic knob |
| Recycle Neurotransmitters through.. | Axoplasmic transport (have to have ATP for it to work)Neurotubules within the axon Transport raw materials Between cell body and synaptic knob Mitochondria is imp. for cell functions with ATP |
| Neuromuscular junction | Synapse (GAP) between neuron and muscle |
| Neuroglandular junction | Synapse (GAP) between neuron and gland |
| Synovial fluid: | reduce friction, Contains slippery proteoglycans secreted by fibroblasts, Functions of synovial fluid lubrication, nutrient distribution, shock absorption |
| The place where the fixed end attaches to a bone, cartilage, or CT is called.. | origin of the muscle. |
| The site where the movable end attaches to another structure is called.. | insertion of the muscle. |
| The origin is typically proximal to the.. | insertion |
| Imaginary part of the pelvis the baby comes through during birth: | pelvic outlet |
| The four types of muscles identified by different patterns of organization are: | parallel, convergent, pennate, circular |
| In a convergent muscle the muscle fibers are: | based over a broad area, but all the fibers come together at a common attachment site |
| Muscles responsible for shrugging shoulders: | trapezius |
| Anaxonic neurons: | (ana- without), no tail, Found in brain and sense organs, Small, All cell processes look alike |
| Bipolar neurons | Found in special sensory organs (sight, smell, hearing); Are small, One dendrite, one axon |
| Unipolar neurons | cell body is budding off, 2 ends; Found in sensory neurons of PNS, Have very long axons, Fused dendrites and axon, Cell body to one side |
| Multipolar neurons | Common in the CNS, Include all skeletal muscle motor neurons; Have very long axons, Multiple dendrites, one axon |
| Three Functional Classifications of Neurons: | sensory, motor, interneurons |
| Sensory Neurons: | afferent (takes info to CNS) neurons of PNS; Monitor internal environment (visceral sensory neurons), Monitor effects of external environment (somatic sensory neurons |
| Motor Neurons: | Efferent (brings it back from CNS to PNS) neurons of PNS |
| Interneurons | assocation neurons |
| Structures of sensory neurons: | Unipolar, Cell bodies grouped in sensory ganglia, Processes (afferent fibers) extend from sensory receptors to CNS |
| Three Types of Sensory Receptors: | Interoceptors, Exteroceptors, Proprioceptors |
| Interoceptors: | Monitor internal systems (digestive, respiratory, cardiovascular, urinary, reproductive) Internal senses (taste, deep pressure, pain) |
| Exteroceptors: | (external) External senses (touch, temperature, pressure), Distance senses (sight, smell, hearing) |
| Proprioceptors: | Monitor position and movement (skeletal muscles and joints) (tells you if ur standing up right, lying down) |
| Motor Neurons: | Carry instructions from CNS to peripheral effectors via efferent fibers (axons) |
| Two major efferent systems: | Somatic nervous system (SNS): includes all somatic motor neurons that innervate skeletal muscles Autonomic (visceral) nervous system: involuntvary visceral motor neurons innervate all other peripheral effectors, smooth muscle, cardiac muscle, glands, adipose tissue |
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