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101 Cards in this Set
- Front
- Back
Function of the PM
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A physical barrier
regulates exchange with environment and responds to environmental outputs via receptors. provides structural support (via juncitons) All functions achieved via phospholipid bilayer |
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Components of the phospholipid bilayer
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2 layers of lipids (heads out, tails in)
Composed of INTEGRAL and PERIPHERAL proteins |
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Integral proteins
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Proteins imbedded into the phospholipid bilayer.
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Peripheral proteins
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Proteins on the surface of the phospholipid bilayer.
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The Cytosol is composed of what two types of fluid.
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Intracellular fluid and extracellular fluid
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Composition of Intracellular Fluid
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High K ions, Low Na ions.
- High concentration of proteins, carbs, amino acids, and lipids. Proteins --> enzymes; carbs, AA, and lipids are for energy. |
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Composition of Extracellular Fluid
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Low K ion and High Na ions
Low concentration of proteins NO concentration of AA, lipids, or carbohydrates. |
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Explain Protein Synthesis
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DNA --> RNA --> Proteins
DNA --> RNA is transcription RNA --> Proteins is translation Proteins the fold in the ER, packaged, labeled and exit in transport vesicles. If they are to LEAVE the cell, they would take part EXOCYTOSIS. |
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What is protein degradation?
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Old proteins are destroyed.
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What part of the cell breaks down protein? Why does it break the proteins down?
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The Lysosome is in charge of destroying proteins.
This could be due to damaged organelles or foreign materials (i.e. bacteria and pathogens). |
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What can diffuse through the Plasma Membrane
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- Small lipids move directly through.
Small or charged particles or water particles require channels. Large proteins require carriers Pumps require ATP will move substances against gradient. |
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Simple Diffusion
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No ATP (passive)
Moves along concentration gradient (high to low) Alcohol, lipids, fatty acids, oxygen, and carbon dioxide. Fat soluble can cross the hydrophobic bilayer |
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Channel-Mediated Diffusion
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NO ATP
- Substances move along gradient - Integral protein channel provides bilayer for water-soluble moleucles. |
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Channel transport
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Transports Water ions
Water soluble molecules require channels. |
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Osmosis
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Diffusion of water
If solutes cannot move through the cell, water will dilute the solute. - Cells adjust to changing solute concentrations. (High to low) |
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Tonicity definition
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how a solution affects a cell.
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Isotonic definition
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Same internal/external concentrations
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Hypotonic
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Water moves in (bloats).
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Hypertonic
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Water moves out (shrivels).
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Carrier-Mediated Transport
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Can be active OR passive.
Is specific to one action (a one-carrier job) Co-transport (symport) Counter-transport (antiport). |
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Passive Carrier-Mediated Transport
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Carrier Proteins
Specially shaped receptors Binds to a specific protein so that it can move into a receptor to be moved into the cell (i.e. glucose). |
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Primary Active Transport
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- Against gradient
- ATP is required. Ion pumps require energy to move through the cell. Antiport ex - sodium/potassium channels require ATP |
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Secondary Active Transport
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"Piggy backing"
- Gradient set by the Primary Active Transport - Glucose sodium Cotransporter (glucose rides a sodium gradient to enter the cell) --> does not directly use the ATP to move through. |
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Neurons basic functions
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Communicates
Integrates INformation Controls body processes. |
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What components of the body are composed of neurons?
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Brain
Spinal cord Nerves Sensory structures |
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Parts of the neuron
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Dendrites
Soma Axolemma Telodendria Synaptic terminals Axon hillock ` |
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How do neurons communicate?
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Dendrites receive info --> decisions are made at the Axon Hillock --> the axon delivers the info --> Terminals then send the message to the next cell via the synapse (presynaptic --> postsynaptic).
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Types of membrane potential
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Resting Potential
Graded Potential Action Potential |
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basics of Resting potential
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All neural activity will begin at rest
- Stimulus is required to activate cell (synaptic activity/info processing will activate it). |
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basics of Graded potential
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Deviation from rest
-Graded potential weakens as distance from stimulus increases. Vary as opposed to being all-or-none. |
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basics of action potential
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All or non only occurs if stimulus is strong enough.
- if graded potential is strong enough, it will be activated. Neurons action potential occurs in the axon and the effect is consistent through the length of the axon. |
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Resting membrane potential (ICF and ECF - composition; voltage; permeability).
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ECF and ICF differ in ionic composition.
Permeability is ion specific ICF will have a voltage of -70 mV |
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Chemical (passive) force on the PM
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Potassium out and sodium in.
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Electrical forces on the PM
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ICF is negatively charged
ECF is positive --> potential is crated by separation of charge. Resting membrane potential is -70mV in most cells. Flow of charged particles occurs when channels open. |
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Electrochemical gradient
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Sum of chemical and electrical forces.
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Electrochemical force of K+: chemically and electrical
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Chemical
High concentration of potassium inside Pressure for potassium to diffuse outside Electrical Positive charge of potassium outside Pressure for potassium to diffuse inside. |
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Electrochemical force on Sodium: chemically and electrically
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Chemical:
High concentration of sodium outside Pressure for sodium to move inside. Electrical: Positive charge: outside Pressure for sodium to move inside. |
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Sodium Potassium Exchange Pump
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Pump uses energy to maintain/restore gradients to resting conditions.
-always fighting leak channels. -A pump moves 2 potassium IN and 3 sodium out (to maintain a higher concentration of potassium inside). |
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Is electrochemical gradients a form of potential energy?
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Yes! It temporarily changes in permeability release energy.
This stimulation can change the permeability of Active channels (gated channels) This stimulation will allow cells to commmunicate. |
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Chemically gated channel
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ACh must attach to a binding site which will open the channel and allow the receptor into the cell.
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Voltage gated channel
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When voltage increases from -70mV to -60mV, the channels opens to allow receptors in. When the channel increases to +30mV, the gate closes.
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Mechanically gated channel
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When pressure is applied to the channel, it will open. When pressure is removed, it will close.
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Are dendrites chemically gated or voltage gated? How about Axon and the telodendria?
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dendrites are chemically gated.
axon and telodendria is voltage gated. |
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When chemically gated channels open...what happens?
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The voltage changes and a graded potential is produced.
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What are the two choices a neuron has once a Graded/local potential is produced and it is no longer at rest?
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Depolarization - more positive than rest
Hyper-polarization - more negative than rest. once the stimulus has been removed, it will reset "repolarization". |
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How do neurons communicate?
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If graded potential reaches (-60 to -55 mV), action potential will be fired.
Graded potential is the sum of depolarization and hyperpolarization events in cell body. |
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Action potential properties
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All-or-none
threshold of -60 to -55 mV cannot be stopped --> hillock to terminals refractory period follows |
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Action potential step by step
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1. Threshold triggers voltage gated Na channels to open in axon.
2. Axon depolarizes as sodium enter ICF 3. Axon reaches maximal depolarization and so Na channels inactivate and K channels activate and open. 4. K leaves ICF so that the cell can begin to repolarize. 5. K channels close, but are slow --> slightly negative before back to normal. |
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What does the Refractory period determine?
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Direction
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What does the myelination determine?
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Speed
Unmyelinated slow continuous propagation. Myelinated fast (5m/s) - saltatory propagation (leaping). |
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Affects and causes of Demyelination (also treatments).
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- pain/loss of sensation in extremities
- loss of motor control, paralysis -Causes: heavy metal poisoning kills the glia - Leather disease (Diphtheria) - bacterial infection, kills schwann cells. -Multiple sclerosis (scarring) - recurrent demyelination that worsens overtime. - Guillain-Barre (autoimmune; PNS, extremities first) Treatments: steroids, immune suppressants. |
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Propagation after the terminal...
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Action potential stops at the terminal...signal must cross space and so the electrical turns to chemical.
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The Synapse is...
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-two cells coming together
-Presynaptic cell (a neuron which sends chemical information) - Postsynaptic cell (can be another neuron or just another cell and it must have receptors). |
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Events at a synapse
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1. action potential reaches axon terminal
2. depolarization at terminal triggers Ca entry. 3. Ca singals exocytosis of the NT 4. NT crosses cleft 5. NT binds receptors on post-synaptic cell. 6. Postsynaptic cell is stimulated, then NT is removed. |
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Cholinergic and Andrenergic
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Cholinergic: acetylcholine, Ach as the NT
Norepinephrine, adrenergic synapses. |
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Neuronal integration and decision making
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a post-synaptic cell can have a lot of receptors (cholinergic and andrenergic) so it will respond to NTs released from different types of neurons and will make a "decision". The result will be:
EPSP (excitatory postsynaptic potential). IPSP (inhibitory postsynaptic potential). |
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Spatial vs. Temporal Summation
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Spatial summation: sources of stimulation arrive simultaneously but at different locations.
Temporal summation: a membrane receives two depolarizing stimuli from the same source in rapid succession. |
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Central nervous System - anatomical components
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Spinal cord and brain
- functions of the CNA are to process and coordinate: --Sensory information and execute motor commands. -- Higher functions, intelligence, memory, learning, and emotion. |
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PNS - anatomical components
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All neural tissue except CNA
- mainly composed of nerves (bundles of axons) -Peripheral nerves (cranial and spinal nerves). |
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PNS - functional divisions
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- brings sensory info to CNS eceptors and nerves.
- Brings out (efferent) motor information from CNS to target organs (muscles and glands) |
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The two divisions of the PNS are...
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Somatic nervous system
Autonomic Nervous system |
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Somatic Nervous System (SNS)
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skeletal muscles; voluntary
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Autonomic Nervous System (ANS)
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Auto = self
-visceral motor (smooth muscles, glands; involuntary) Antagonistic Divisions (parasympathetic;sympathetic) |
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Explain spinal reflexes
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CNS "make decisions"
- motor output decisions are based on sensory INPUT Brain deals with the complex decisions and the Spinal cord handles the reflexes. |
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Withdrawal Reflex steps
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1. Stimulus arrives (receptor is activated)
2. ACtivation of sensory neuron (graded potential, propagation of action potential) 3. Information processing (presynaptic cell releases NT to postsynaptic cell; EPSP activates postsynaptic cell) 4. Activation of motor neuron (NT activates EPSP or IPSP) 5. Response of peripheral effector (motor neuron releases NT; effector responds). |
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innate reflex
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simple; withdrawal
complex; chewing, suckling, eye-tracking |
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Acquired/Learned Reflex
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enhanced by repetition (muscle memory)
breaking while driving, athletic skills. |
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Somatic reflex
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involuntary control of voluntary muscles
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Visceral reflex
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autonomic**
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Monosynaptic reflex
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sensory direct to motor (Fast)
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Polysynaptic reflex
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many neurons (slow); more complex.
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Withdrawal is what type of reflex?
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Flexor reflex: motor output is on the same side as sensory input.
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What is the crossed extensor?
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Motor output is on opposite side
- complements flexor reflex (i.e. stepping on a lego, you move the weight onto your other foot to lift the foot that has been injured). |
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Contralateral reflex
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response on opposite side of the body
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Babinski Reflex
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Plantar reflex, a curling of the toes is seen in healthy adults
The Bainski sign - occurs when the foot moves up instead of curling down (it is normal in infants, but bad in adults) Used to test CNS injuries. |
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Brains affect on spinal reflexes
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Requires a conscious effort
Can oppose (INHIBIT) or fine-tune (FACILITATE) |
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Autonomic Nervous System
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Unconscious regulation of visceral function
-routine homeostatic adjustments in body's systems |
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Divisions of the ANS
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- Sympathetic and Parasympathetic
--often oppose each other (excitation vs. inhibition) --work inependently (some organs only have sympa or para) - can work together --Usually PARASYMPATHETIC DOMINATES --SYMPATHETIC ACTIVATES WITH STRESS |
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What section of the brain contains an Autonomic control center?
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The hypothalamus
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Sympathetic Activity
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- heightened mental alertness
- increased metabolic rate - reduced digestive and urinary function - activation of energy reserves - increased respiratory rate/dilation of respiratory passages - increased heart rate and blood pressure - activation of sweat glands (these are all responses to stress) |
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Parasympathetic Activity
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- Decreased metabolic rate
- Increased digestive and salivary gland secretion - Increased digestive motility - Simulation of urination and defecation - Decreased heart rate and blood pressure |
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Cholinergic synapses
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release and respond to acetylcholine
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The adrenal gland
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secretes epinephrine
aka adrenaline - it is also part of the nervous system |
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Skeletal muscle functions
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movement
posture guard entrances and exits (digestive and urinary system control) Maintain temp/produce heat support and protect soft tissues store nutrients |
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Are skeletal muscle fibers small or big?
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they are large - multinucleate (many nuclei) that adapt to make many copies of muscle proteins and enzymes.
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Sarcolemma
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plasma membrane
-change in transmembrane potential is first step in triggering contraciton. |
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Sarcoplasm
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Cytoplasm
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Transverse tubules (T-tubules)
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help spread action potentials.
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how many NMJ does a muscle fiber have? (NMJ = neuromuscular junction)
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One NMF/every muscle fiber.
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Myofibrils
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smaller structures in a muscle cell.
contain myofilaments and tintin (thin myofilamints are ACTIN and thick ones are MYOSIN). shorten, and cause CONTRACTIONS. anchored to sarcolemma. |
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Sarcomere
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Functional unit of muscle.
Units of thick and tinfilaments to stabilize contraction. 10,000 sarcomeres/myofibril |
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Sarcoplasmic Reticulum
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Tubular network around each myofibril
conneted to t-tubules large Calcium chambers called TERMINAL CITERNAE |
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what are terminal cisternae
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large calcium chambers
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Calcium concentration in ICF and in SR
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ICF: low
SR: high Calcium is released from the sarcoplasmic reticulum into the intracellular fluid to trigger muscle contractions. |
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Sliding filaments and contraction requires what type of control?
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Neural control...stimulation from a motor neuron is required.
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Excitation-concentrationcoupling
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Step 1: calcium release
Step 2: Thick and thin filament interactions in the sarcomere. Step 3: Muscle fiber contraction (ATP required) Step 4: TEnsion production. |
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The Sarcomere: Actin
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ball shaped proteins that are strung together, has an "active site" that will do soemthing when exposed.
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tropomyosin
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covers the top of the actin
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troponin
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regulatory protein that repeat itself on the tropomyosin.
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Thin filaments of the sarcomere are...
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actin
tropomyosin troponin |
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Thick filaments of the sarcomere are...
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myosin
titin |