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58 Cards in this Set
- Front
- Back
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Invertebrate Nervous Systems
4 classes of invertebrates to know |
- Protozoa
- Cnidaria - Annelida - Arthropoda |
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Protozoa
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- Unicellular
- no nervous system - external stimuli |
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Cnidaria
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- simple nervous system: NERVE NET
- net has limited centralization. |
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Arthropoda
whats evolved in arthropoda? how does it detect sound? percieve images? |
- brain similar to annelida
- more specialized (organs) - compound or simple eyes - sound detector TYMPANUM |
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Vertebrate Nervous Systems: The Neuron
anatomy? |
- basic building block of vertebrate n. system.
- anatomy: 1. dendrites 2, cell body 3. axons |
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Neuron Anatomy: Dendrites (think of greek translation..)
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- cytoplasmic extension of cell body
- recieve information, transmit it to cell. |
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Neuron Anatomy: Cell Body
does it have a nucleus? what does it regulate? |
- has nucleus
- controls metabolism of neuron |
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Neuron Anatomy: Axon
what is it covered by? what makes the cover material? in the PNS/CNS? Is all the axon myelinated? |
- long part of neuron
- transmits signals from cell body - covered by myelination, which acts as a insulator. helps propagate A.P. faster. - Schwann cells make it in the PNS - Oligodendrocytes make it in the CNS - no, there are gaps in the myelin sheath, called nodes of Ranvier. |
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Neuron Anatomy: Synaptic terminals
what does it do when it recieves the signal from the axon? |
- end of neuron
- release NT's into synaptic cleft (synapse) -- synaptic cleft (synapse) is region between terminal and dendrites of next neuron. |
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Neuron Function
What is the resting potential? |
1. recieve signals from sensory receptors or other neurons.
2. transfer info along axon, eventually to target tissue. - the potential difference between the extracellular space and the intracellular space when neuron is at rest. |
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Resting Potential
postiive or negative? how maintained? |
- resting membrane potential (RMP) is -70 mV.
1. it is maintained by selective ionic permeability and an active Na+/K+ ATPase. 3 Na+ out for every 2K+ in. 2. RMP stays negative because membrane is selectively permeable to K+, diffuses down gradient, leaving negative charge. |
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Action Potentials
what makes them? |
- EPSPs and IPSPs from other cells hit dendrite
- if enough EPSP's, cell will be depolarized (hitting threshold of -50 mV). |
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3 actions taker place:
first? effect? second? effect? third? effect? What recovers the RMP? what is the period after the Action potential? |
1. depolarizations in Dendritic/cell body region
2. activates V.gated Na+ channels OPEN 3. causes big depolarization 4. Once getting close to peak (+35 mV) V.gated Na+ CLOSES, V.gated K channels OPEN. 5. Repolarization occurs 6. Sometimes hyperpolarization (repol. goes past RMP) 7. Na+/K+ ATPase restablishes RMP. - Refractory period. (When Na+ channels recover) |
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Impulse propagation
axons propagate AP bidirectionally right? what factors contribute to better propagation? |
- no, cannot go reverse because of refractory period makes it impossible.
- GREATER diameter and GREATER myelination = faster impulse. - only permeable to nodes of ranvier, causes "jumping" of A.P.'s. cause only way ions can get in. |
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Synapse
what other cell types can neurons communicate to? |
- gap between axon terminal (presynaptic) and dendrites of the another neuron (postsynaptic).
- "Effector Cells" (muscles cells or glandular cells) |
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Synapse Pathway (start from axon)
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1. A.P.'s from axon reach synaptic terminal (presynaptic)
2. Depolarizes terminal 3. synaptic vesicles fuse with presynaptic membrane 4. vesicles release NT's upon fusion into synaptic cleft (synapse) 5. NT's bind to receptors on postsynaptic membrane 6. can depolarize post synapse 7. causes another A.P. |
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What happens to the NT's in the synaptic cleft (synapse)?
3 types of movement |
1. remove to nerve terminal via UPTAKE CARRIERS. the reused or degraded.
2. SYNAPTIC ENZYMES may degrade them in cleft. ex. acetylcholinesterase degrades Ach. 3. may DIFFUSE out of synapse. |
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Drug effects on synapse
(3 examples) |
- Curare -- blocks postsynaptic Ach receptors (no ennervation of muscles). leads to paralysis.
- Botulism toxin -- prevents release of Ach from presynaptic membrane = paralysis. - Anticholinesterase -- nerve gases/insecticide. inhibit acetylcholinesterase activity. so synaptic clef Ach continues to bind postsynaptic receptors. = no coordinated muscle contractions. |
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Veterbrate Nervous System Organization
2 categories of neurons |
- interneurons (just brain and spine)
- Efferent neurons (go from brain or spine to other parts of body) |
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Anatomy of nerves
whats a network of nerves called? |
- basically a bundles of axons covered with Connective tissue.
- Plexus. |
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Neuronal cell cluster types (2)
what two types is the Nervous system divided into? |
- In PNS, clusters are called GANGLIA
- In CNS, clusters are called NUCLEI |
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CNS (Central Nervous System)
what are its two parts? |
- made up of Brain and Spinal cord.
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Brain breakdown (3 parts)
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- Forebrain
- Midbrain (Mesencephalon) - Hindbrain |
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Forebrain: function and anatomy
2 parts? |
- Telencephalon
- Diencephalon |
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Telencephalon
major piece? function? |
- Cerebral cortex -- a buncha gray matter
- The cortex processes and integrates sensory input and motor responses - Also, important for memory and creativity. |
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Inferior portion of Forebrain? function?
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- Olfactory Bulb
- center for reception and integration of OLFACTORY OR ODOR input. |
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Diencephalon
2 major parts |
- hypothalamus
- thalamus |
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Thalamus
function? |
- Relay and integration center for the SPINAL CORD and CEREBRAL CORTEX.
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Hypothalamus
Function? what does it also do? hint:which system does it effect? |
- controls visceral functions; hunger, thirst, sex drive, waterbalance, blood pressure, and temp regul.
- role in controlling endocrine system via feedback mechanism. |
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Midbrain (Mesencephalon)
main function? other role? |
- relay center for VISUAL and AUDITORY impulses.
- plays important role in MOTOR control. |
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Hindbrain
Location? 3 parts |
- posterior part of brain
--- Cerebellum --- Pons --- Medulla |
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Cerebellum
function? importance? |
- modulates MOTOR A.P.'s from CEREBRAL CORTEX
- maintains balance, hand-eye coord., and timing of rapid movement. |
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Pons
function? importance? |
- Acts as relay center. helps CORTEX communicate with CEREBELLUM
- helps connect cortex an cerebellum |
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Medulla (Medulla Oblongata)
function? importance? |
- Controls breathing, heart rate, G.I. activity.
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What does the midbrain + pons + medulla make up?
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- the BRAINSTEM
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CNS part two: Spinal Cord
how different from brain? |
- built opposite of brain
- brain is OUTER -- gray matter (cell bodies) INNER -- white matter (axons) - spinal cord OUTER -- white matter (axons) motor and sensory INNER -- gray matter (cell bodies) |
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Spinal Cord basic purpose?
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- takes sensory input to brain from body.
- takes motor info to from brain to body. |
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Spinal cord
- sensory pathway - motor pathway |
1. sensory info enters spinal cord through dorsal horn
2. sensory info hits DRG neurons 3. hits synapse 4. motor information exits via the ventral horn. 5. hits motor neurons |
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PNS (Peripheral Nervous System)
2 parts how does it interact with the CNS |
- Somatic Nervous System
- Autonomic Nervous System -- it is the MOTOR neurons LEAVING CNS -- it is the SENSORY neurons ENTERING CNS |
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Somatic Nervous System (SNS)
what does it affect? |
- innervates SKELETAL muscles and is responsible for VOLUNTARY MOVEMENT.
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Autonomic Nervous System (ANS)
what does it affect? |
- involuntary system
-innervates cardiac and smooth muscle ---cardiac ---respiratory ---excretory |
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ANS
importance? |
- blood pressure cnntrol, g.i. motility, excretory process, respiration, and reproductive
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ANS
Divided into two parts |
- sympathetic nervous system
- parasympathetic nervous system |
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Sympathetic nervous system
what does it increase? primary NT? |
- Think "fight or flight"
- INCREASES Blood pressure, Heart Rate, Blood to skeletal muscle, Dilation of bronchioles, Gas Exchange - Decreases Gut Motility - primary NT is Norepinephrine |
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Parasympathetic Nervous System
what does it do with energy? what does it increase?decrease? what is a important parasympathetic nerve? What is its primary NT? |
- "Rest and Digest"
- does opposite of sympathetic - conserves energy - Decreases H.R. - Increases Gut Motility - Vagus nerve ---ennervates abdominal and thoracic viscera. - Acetylcholine (Ach) is its primary neurotransmitter. |
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THE EYE
purpose? layer anatomy? (3 layers) |
- to transmit energy (as photons) into information about intensity,color, and shape to the brain.
- 3 layers of eye Sclera -> thick white layer Choroid -> Supplies blood to retina Retina -> Contains photoreceptors. |
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light/image pathway (5 steps)
what controls diameter of pupil |
1. Starts!
2. Cornea (focuses rays) 3. Pupil (iris controls diameter of pupil) 4. lens (controlled by ciliary muscles) 5. lens then focuses the image on the retina. |
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The Retina (Photoreceptors)
two types of main photoreceptors? what are the pigments of each type? |
- Cones -> respond to INCREASED intensity and color
-> pigments: red, blue, green absorbers - Rods -> Responds to DECREASED intensity, important for night time. -> pigments: Rhodopsin (absorbs single wave length) |
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image pathway after reach Retina (4 steps)
what are the 3 cell types involved in pathway? |
1. Image hits retina
2. then detected by photoreceptors (rods/cones) 3. photoreceptors synapse to Bipolar cells. 4. Bipolar cells synapse to Ganglion cells.. |
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What happens after reaches ganglion?
where does optic nerve exit eye? |
1. axons of the ganglion cells bundle to form optic nerves
2. optic nerves conduct visual info to brain. - optic nerve exits "blind spot", no photoreceptors there. |
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Fovea? whats that?
what photoreceptor is most prevalent? why is it important? |
- small area of the retina (just a little above blind spot)
- lots of CONES - important for high-acuity vision. |
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Eye humor, no its not jokes (2 types)
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- vitreous humor
-> maintains shape and optical properties - aqueous humor -> formed by eye, exits through ducts to join venous blood. |
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Eye disorders (5 types)
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- Myopia
- Hyperopia - Astigmatism - Cataracts - Glaucoma |
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Myopia vs. Hyperopia
whats another name for myopia? whats another name for hyperopia? |
- Myopia (nearsightedness) is when image is focused in FRONT of retina.
- Hyperopia (farsightedness) is when image is focused BEHIND the retina. |
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Astigmatism
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- when the cornea is irregularly shaped.
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Cataracts
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- causes lens to become opaque; light cannot enter the eye
- leads to BLINDNESS |
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Glaucoma
hint: not so "funny" |
- INCREASE in pressure in the eye due to the BLOCKING of the outflow of the aqueous humor.
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The Ear (3 regions)
Pathway (also explains audiotory anatomy) (7 steps) what does each region consist of? whats special about the eardrum? whats its other name? what is converted? what is the channel the signal runs along? |
- outer ear, middle ear, inner ear
1. sound waves enter outer ear (auricle and auditory canal) 2. then travels to middle ear tympanic membrane (Eardrum). the tympanic mem. vibrates at same frequency as incoming sound. 2a. in between the middle and inner ear resides the ossicles (ear bones). They consist of malleus, incus, and stapes. 3. The ossicles amplify the auditory stimulus and transmit it through the oval window (leads to fliud filled inner ear). 3a. the inner ear consist of the cochlea and vestibular apparatus. (maintains equilibrium) 4. the vibration of the ossicles exerts pressure on cochlear fluid. 5. this pressure stimulates hair cells in the basilar membrane 6. creates A.P.'s 7. A.P's travel via the auditory (cochlear) nerve to the brain for processing. |
