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165 Cards in this Set
- Front
- Back
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Contrast functions of the nervous system and endocrine system in maintaining homeostasis |
Nervous system: responds rapidly Endocrine: operates slowly |
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Central Nervous System |
Brain and spinal cord |
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Afferent |
Sensory nerves |
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Somatic Nervous System |
Carry information from CNS to skeletal muscles |
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Autonomic Nervous System |
Consists of sympathetic and parasympathetic divisions Nerves that convey impulses to smooth muscle, cardiac muscle, and glands; involuntary |
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Peripheral Nervous System |
Cranial nerves, spinal nerves, ganglia, and sensory receptors |
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Enteric Nervous System |
"Brain of the gut" |
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Functions of nervous system |
Sensory, intergrative, motor |
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Neurons |
Conduct impulses from one part of the nervous system to another |
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Neuroglia |
Provide support and protection for the nervous system Bind tissue to blood vessels, form myelin, and serve phagocytic functions Smaller in size, more abundant in number Can form brain tumors known as gliomas |
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Astrocyte |
Support/protect neurons to help neurons grow Part of CNS |
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Oligodendrocytes |
Produce and maintain myelin sheath of CNS Part of CNS |
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Microglia |
Phagocytic Part of CNS |
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Ependymal cells |
Line ventricles of brain and central canal of spinal cord Part of CNS |
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Schwann cells |
Produce myelin around axons of PNS neurons Part of PNS Required for regeneration of axons and dendrites, form regeneration tube across gap in injured axon |
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Satellite cells |
Supports neurons and regulates exchange of materials Part of PNS |
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Cell body |
Contains nucleus; cannot regenerate since lacks miotic apparatus |
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Myelin |
Lipid and Protein covering that insulates many axons and increases speed of nerve impulse transmission |
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Dendrite |
Conducts impulses toward cell body |
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Axon |
Conducts impulses away from cell body; has synaptic end bulbs that secrete neurotransmitter |
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Mitochondria |
Provide energy for neurons |
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White matter |
Consists of: myelinated axons White because of myelintracts that carry impulses "north" and "south" within the cord are made of white matter |
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Grey matter |
Cell bodies of neurons that are unmyelinated Inner h core seen in cross section |
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Nerve action potentials |
Impulses |
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2 features in nerve cell membrane (necessary for impulse to take place) |
The existence of resting membrane potential Presence of specific types of ion channels |
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Phospholipid bilayer permits |
Little passage of ions |
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Two types of ion channels provide main path for flow current across membrane |
Leakage channels (always open) Voltage-gated channels (opens only in response to a change in the membrane potential) |
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Resting nerve cell membrane |
Polarized (inside of cell more negative than outside) Prerequisite for starting a nerve impulse About -70 mV |
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The membrane has many more ____ leakage channels, causing more ___ to leak out of the cell compared to the amount of ___ that leaks in |
K+, K+, Na+ |
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Na+/K+ pump |
Form of active transport Involved with maintenance of resting potential Na+ ions that do not leak into cell is pumped out Constant supply of energy in form of ATP is required to maintain pump Negativity inside cell attracts K+ back into cell |
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Excitability of neurons |
The ability of muscle fibers and neurons to convert stimuli into action potentials |
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Stimulus |
Anything in the cells environment that can change the resting membrane potential |
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Threshold |
When a stimulus causes the membrane to depolarize to a critical level |
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Stimulus |
Causes nerve cell membrane to become more permeable to Na+, then enter cell as Na+ voltage-gated channels open |
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Resting membrane potential? (Number) |
-70 mV |
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Na+ enters cell, inside of membrane becomes more (+\-)? |
Positive |
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Potential after Na+ begins entering cell (#)? |
-60 mV |
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Depolarization |
Na+ enters cell making the inside of the membrane more positive Causes structural changes in more Na+ channels so that even more Na+ enters |
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Threshold (#) |
-55 mV |
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When do the Na+ channels close? |
When inside of membrane potential is reversed at +30 mV |
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Repolarization |
K+ voltage-gated channels at site of original stimulus open K+ more concentrated inside cell, so K+ diffuses out Causes inside of membrane to become more negative again and return to resting potential (-70 mV) |
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Hyperpolarization |
Overshoot of outflow of K+, membrane potential is -80 mV |
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All-or-nothing principle |
Stimulus is strong enough to cause depolarization to threshold, weak stimulus fails to cause threshold-level depolarization, not elicit action potential |
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Continuous conduction |
Propagation of an action potential in a step-by-step depolarization of each adjacent area of an axon membrane |
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Slatory conduction |
Occurs along myelinated nerve fibers Transmission is faster bc nodes of Rainer |
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Which nerve fibers are likely to conduct impulses more rapidly? |
Fibers with large diameter |
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Which nerve fibers conduct impulses faster? |
Warm |
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Anatomical pathway of a synapse |
End bulb of presynaptic neuron Voltage-gated Ca2+ channels Synaptic vesicle Synaptic cleft Neurotransmitter Neurotransmitter receptor |
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What causes Ca2+ to enter voltage-gated Ca2+ channels of presynaptic bulb? |
Ca2+ are more concentrated in the interstitial fluid so it flows into the synaptic end bulb to reach equilibrium |
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Effect of entrance of Ca2+ into voltage-gated channels? |
Triggers exocytosis of some synaptic vesicles, releasing thousands of neurotransmitter molecules into synaptic cleft |
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Explain why only one-way impulse conduction of synapse occurs |
Only synaptic bulbs of presynaptic neurons release neurotransmitter |
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Summation |
Excitatory and inhibitory effects that the postsynaptic neuron intergrates |
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3 main mechanisms by which neurotransmitters are normally removed from the synaptic cleft |
1. Some of the released neurotransmitter molecule diffuse away from the synaptic cleft 2. Some neurons are destroyed by enzymes 3. Many neurotransmitters are actively transported back into the neuron that released them (reputake) |
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How does Prozac or other SSRIs work |
THey block reputake of specific neurotransmitters such as serotonin which prolongs the activity of serotonin at synapse in the brain |
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GABA and glycerine |
Inhibitory |
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Glutamate |
Excitatory |
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3 neurotransmitters formed by amino acids |
Norepinephrine Dopamine Serotonin |
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Produced as needed and plays role in learning and memory (neurotransmitter) |
NO |
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Endorphins |
Body's natural pain killers Production increased by acupuncture treatments (anesthesia and euphoria) |
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Serotonin |
Mood control and helps induce sleep |
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Protection afforded by body for CNS |
Meninges, bones, CSF |
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Order of meninges from outside inward |
Dura mater, subdural space, arachnoid mater, subarachnoid space, pia mater |
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Where is the cerebrospinal fluid located? |
Subarachnoid space |
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Inflammation of meninges |
Meningitis |
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Where are the enlargements of the spinal cord? |
Cervical and lumbar |
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Cauda equina |
Whisps of hair-like Roots of the spinal nerves |
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Ascending tracts in white matter are ___ |
Sensory |
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Descending tracts in white matter are ___ |
Motor |
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Why are tracts white? |
Consist of axons that are myelinated |
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Pairs of spinal nerves |
31 all together 8 cervical 12 thoracic 5 lumbar 5 sacral 1 coccygeal |
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Which spinal nerves form the cauda equina? |
Lumbar |
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One root of spinal nerve (posterior) is___ |
Sensory |
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One root of spinal nerve (anterior) is _____ |
Motor |
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What is the name for the covering of a single axon? |
Endoneurium |
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What is the name for the covering around an entire nerve? |
Epinerium |
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What do most spinal nerves form shortly after passing through intervertebral formina? |
Plexuses |
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Where do spinal nerves not form into plexuses but do form segmental arrangements? |
Thoracic region |
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Brachial plexus |
Provides the entire nerve supply for the arm Forms ulnar, radial, and axillary nerves |
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Cervical plexus |
Contains origins for the Phoenix nerve that supplies diaphragm Supplies nerves to scalp, neck, and part of shoulder |
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Sacral plexus |
Forms the largest nerve in the body (sciatic), which supplies posterior of thigh and leg |
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Lumbar plexus |
Supplies fibers to femoral nerve, which innervates the quadriceps, so injury to this plexus would interfere with action such as kicking a leg upward |
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How much CSF does the entire nervous system contain? |
80-150 mL or 1/3 to 2/3 of a cup |
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What color is the CSF |
Clear, colorless |
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Functions of CSF |
Contains wastes Contains nutrients Contains red blood cells Serves as a shock absorber for brain and cord |
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How and where is the CSF formed? |
By filtration and secretion from capillaries called choroid plexuses in the ventricles of the brain |
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Pathway of CSF? |
Formed initially from blood, circulates around brain and cord within subarachnoid space, passes via projections (villi) of the arachnoid into blood vessels (superior saggital sinus) surrounding the brain, and finally flows back into blood |
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What is the name of the condition that is an excessive accumulation of CSF? |
Hydrocephalus |
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Hypothalamus |
Principle regulator of visceral activities (acts as liaison between cerebral cortex and autonomic nerves that control viscera) Feelings of hunger, fullness, and thirst stimulate centers here so that you can respond accordingly Serves as body's thermostat, regulating body temp. Neuroendocrine structure since it helps to regulate the pituitary Help to regulate the body's biological clock |
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Midbrain |
Site of cerebral peduncles, contain major sensory and motor tracts within brain Cranial nerves III-IV attach Site of substantia infra and red nucleus, both involved with muscle coordination |
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Pons |
Cranial nerves V-VII attach Name means bridge. Connects medulla and midbrain |
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Medulla |
Cranial VIII-XII nerves Regulation of heart, blood pressure, respiration occurs by centers located here. |
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Thalamus |
Almost all sensations are relayed through here, and these contribute to maintenance of consciousness |
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Pineal gland |
Help to regulate the body's biological clock |
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Primary somatosensory area |
In the post central gyrus Receives sensations of pain, touch, itching, tickling, pressure, and temperature In the parietal lobe |
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Primary visual area |
In the occipital lobe |
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Primary auditory area |
In the temporal lobe, permits hearing |
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Primary motor area |
In the pre central gyrus of the frontal lobe Controls specific muscles or groups of muscles |
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Primary olfactory area |
Controls smell |
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Anterior cerebrum is involved with ____ control? |
Motor |
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Posterior of cerebrum involved with ____ functions? |
Sensory |
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Which sensory areas recieve sensations? |
Primary |
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Which sensory areas are involved with interpretation and memory of sensations? |
Association |
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Name all the cranial nerves in order (I-XII) |
Olfactory Optic Oculomotor Trochlear Trigeminal Abducens Facial Vestibulocochear Glossopharyngeal Vagus Accessory Hypoglossal |
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Olfactory |
Smell |
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Optic |
Vision |
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Oculomotor |
movement of upper eyelid and eyeball, alters shape of lens for near vision and constricts pupil |
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Trochlear |
Movement of the eyeball |
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Trigeminal |
chewing, touch, pain, and temperature sensations and muscle sense (proprioception) |
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Abducens |
movement of the eyeball |
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Facial nerve |
taste; muscle sense, touch, pain, and temperature sensations, facial expressions, secretion of tears and saliva |
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Vestibulocochlear |
Equilibrium, hearing |
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Glossopharyngeal |
monitoring blood pressure, monitoring oxygen and carbon dioxide in blood for regulation of breathing, swallowing, speech, secretion of saliva |
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Vagus |
monitoring blood pressure, monitoring oxygen and carbon dioxide in blood for regulation, voice production, smooth muscle contraction and relaxation in organs of GI tract, slowing of heart rate, secretion of digestive fluid |
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Accessory nerve |
Movements of head and shoulders |
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Hypoglossal |
Movements of tongue during speech and swallowing |
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Which cranial nerve originates from the brain stem and from the spinal cord? |
Accessory nerve |
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What is the eighth cranial nerve? |
Vestibulocochear |
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What is the seventh cranial nerve? |
Facial |
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What is the sixth cranial nerve? |
Abducens |
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What is the fifth cranial nerve? |
Trigeminal |
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What is the third cranial nerve? |
Oculomotor |
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What is the second cranial nerve? |
Optic |
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What is the first cranial nerve? |
Olfactory |
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What is the ninth cranial nerve? |
Glossopharyngeal |
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What is the tenth cranial nerve? |
Vagus |
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What is the eleventh cranial nerve? |
Accessory nerve |
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What is the twelfth cranial nerve? |
Hypoglosseal |
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Which cranial nerve is widely distributed into the neck, thorax, and abdomen? |
Vagus |
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Which cranial nerve senses toothaches, pain under a contact lens, or wind on the face? |
Trigeminal |
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Which is the largest cranial nerve? |
Trigeminal |
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What are the three parts of the trigeminal cranial nerve? |
Ophthalmic Maxillary Mandibular |
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Which cells are more able to reproduce after birth? |
Neuroglia |
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Monoplegia |
Paralysis of one extremity |
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Paraplegia |
Paralysis of both legs |
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Quadriplegia |
Paralysis of both arms and both legs |
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Hemiplegia |
Paralysis of the arm, leg, and trunk on one side of the body |
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What is the name for a stroke? |
Cerebrovascular accident (CVA) |
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What is CVA? |
Destruction of brain tissue, hemorrhage from blood vessel in pia mater or brain, blood clots |
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What is TIA? |
Like a stroke but lasts 5-10 minutes, temporary, max intensity immediately |
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ALS (amyotrophic lateral sclerosis) |
Involves excessive buildup of glutamate, and excitatory neurotransmitter that can cause death of neurons |
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Poliomyelitis |
Vaccine had virtually eradicated this disease in the U.S. although recently, domestic incidence has increased Most cases involve only fevers headache, neck and back stiffness, deep muscle pain and weakness; but involvement of motor neurons can lead to serious and death |
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Why is the Autonomic nervous system named that? |
Function in a self- governing manner |
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Is the ANS entirely independent of higher control centers? |
No, the hypothalamus and brain stem control it. |
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Contrast the effectors in the somatic and autonomic nervous systems |
Somatic is skeletal Autonomic is cardiac, smooth, and glands |
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Contrast the types of control in the s and a nervous system |
S voluntary A involuntary |
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Contrast the neural pathways of the somatic and autonomic nervous systems |
S one motor neuron extends from CNS and synapses directly with a skeletal muscle fiber A one motor neuron extends from the CNS and synapses with another motor neuron in a ganglion; the secind motor neuron synapses with an autonomic effector |
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Neurotransmitter in SNS and ANS |
SNS acetylcholine ANS acetylcholine or norepinephrine |
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Action of neurotransmitter on effector SNS V ANS |
SNS always excitatory ANS may be excitatory or inhibitory |
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Name the two divisions of tthe ANS |
Sympathetic and parasympathetic division |
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Dual innervation |
Organs revieve impulses from both sympathetic and parasympathetic neurons |
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What is another name for the sympathetic division? |
Thoracolumbar division |
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Describe the placement of preganglion axons and cell bodies |
Cell bodies: 12 thoracic and first 2 lumbar segments of the spinal cord Axons: emerge from the spinal cord through anterior root of spinal nerve along with axons of somatic motor neurons then extend to to a sympathetic ganglion |
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Why is the Autonomic nervous system named that? |
Function in a self-governing manner |
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Is the ANS entirely independent of higher control centers? |
No, it is regulated by the hypothalamus and brain stem. |
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Effectors of somatic nervous system v. autonomic |
Somatic: skeletal muscles Autonomic: cardiac, smooth muscle, glands |
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Type of control (s v. a) |
S: voluntary A: involuntary |
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Neural pathway of s v. a |
S: one motor neuron extends from CNS and synpases directly eith a skeletal muscle fiber A: one motor extends from the CMS and synapses with another motors neuron in a ganglion; the second motor neuron synapses with an autonomic effector |
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Neurotransmitter of s v. a |
S: acetylcholine A: acetylcholine or norepinephrine |
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Action of neurotransmitter on effector s v. a |
S: always excitatory (causing contraction of skeletal muscle) A: May be excitatory or inhibitory |
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When is the action of a neurotransmitter on effector excitatory in the Autonomic nervous system? |
Contraction of smooth muscle, increased heart rate, increased force of heart contration, increased secretions of glands |
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When is the action of neurotransmitter on effector inhibitory in the autonomic nervous system? |
Relaxation of smooth muscle, decreased heart rate, decreased secretions from glands |
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Name the two divisions of the ANS |
The symapthetic division The parasympathetic division |
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Dual innervation |
The organ receives both parasymapthetic andsympathetic neurons. |
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Are sympathetic preganglion axons long or short? Why? |
Short Because sympathetic trunk ganglion are near the spinal cord |
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Where does the main input to the ANS come from? |
Autonomic sensory neurons |
