Unit 2

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Unit 2
2014-03-02 02:42:47

Physiology, mucles, transportation
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  1. Parts of a Cell
    • Plasma Membrane (Boundary inside and outside)
    • Cytoplasm (Anything in cell, Cytosol & Organelles)
    • Nucleus (DNA)
  2. Plasma Membrane
    • Made of: Lipids & Proteins
    • Structure: Lipid Bilayer, Not fixed in place, Heads (hydrophilic), Tails (hydrophobic)
    • Properties: Fluidity, Selective Permeability
  3. Dowhill Movement
    • High to Low Concentration
    • With the Gradient
  4. Uphill Movement
    • Low to High Concentration
    • Against the Gradient
  5. Passive Transportation
    • Does not require energy
    • Downhill movement
    • Diffusion is main thing happening
    • Statistical Probability for net movemnet
    • Factors: Temp, Size, Steepness of gradient, Distance, and Surface Area
  6. Passive Trasport Across Cell Membranes
    • Simple Diffusion (As if the membrane is not there)
    • Diffusion through channels (Specific with Ions)
    • Facilitated Diffusion (Requires carrier protein)
    • Osmosis (Selectively permeable membrane) water follows the solute (water that is not associated with solute called free water)
  7. Tonicity (Ability of a Solution to alter  size(volume) of a cell)
    • Isotonic: No effect on a cell
    • Hypotonic: Expands the cell
    • Hypertonic: Shivels the cell
  8. Active Transportation
    • Primary Active Transport: Source of energy is ATP (Na+/K+ Pump- 3Na+ out & 2K+ in)
    • Secondary Active Transport: Source of energy is another substances gradient (Antiporters-Opposite physical direction & Symporters- Same physical direction)
  9. Vesicular Transportation
    • Vesicle -> Membrane-bound sac inside a cell
    • Exocytosis: Releasing stuff OUT
    • Endocytosis: Bringing something IN (Phagocytosis [solid], Pinocytosis [fluid], & Receptor-mediated)
  10. Functions of the Nervous System
    • Collect  Information
    • Analyze/Integrate the Information
    • Communicate Iformation
  11. Nervous System VS Endocrine System
    • Time to Respond: Nervous- quicker (msec) Endocrine (sec-days)
    • Duration of Resonse: Nervous- shorter (msec) Endocrine (sec_days)
    • Mode of Communication: Nervous- Electrochemical Endocrine- Chemical
    • Targets: Nervous- Neurons, muscles, glands  Endocrine- all cells
  12. Sympathetic Branch
    • Exercise, Embarrassed, Excitement, Emergency- Increased Sympathetic Response
    • ^ Heart Rate
    • ^ Vasoconstriction (non-essential organs)
    • ^ Vasodilation (heart, skeletal muscles, brain, liver)
    • Vasodilation of Airways
  13. Parasympathetic
    Salivate, Lacrimate, Urinate, Defecate, Digest
  14. Autonomic Tone
    Response to ANS depends on balance of sympathetic and parasympathetic stimulation
  15. Reflex
    Rapid response (Autonomic) to a specific stimulus
  16. Reflex Arc
    The path followed by a signal regulating a reflex
  17. How do neurons communicate?
    Transmit nerve impulses
  18. What are nerve impulses?
    Rapid change in membrane potential
  19. What is a membrane potential?
    • Difference in charge across a cell membrane (Voltage gradient, Electrical Gradient, Charge Gradient)
    • For a neuron at rest, membrane potential is -70mV (Called RMP)
  20. Why is RMP -70mV?
    • Outside of a cell: Na2+  Ca2+  Cl-
    • Inside of a cell: K+  PO43-  Proteins-
    • Cell membranes are leakier to K+
    • Sodium potassium pumps
  21. How does a membrane potential change? (Rapidly)
    • Moving Ions (redistribution)
    • -Ion Channels: Leakage Channels-Always open, Voltage-Gated ChannelsOpen to change in membrane potential, Ligand-Gated Channels- Open to binding of a chemical, Mechanically-Gated Channels- Open to mechanicla stimuli
  22. Graded Potential
    • Magnitude of change (depends on strength of stimulus)
    • Dendrites or cell body
    • Mechanically-Gated or Ligand-Gated Channels
    • Not long distance
    • Depolarization: Less negative (closer to zero- more likely for action potential)
    • Hyperpolarization: More negative (further from zero- less likely to produce action potential)
  23. How graded potentials trigger nerve impulses?
    • Action potentials are all or nothing
    • Occurs in Axons
    • Voltage-Gated Channels
    • Travel long distances
  24. After a stimulus reaches threshold (-55) there is a action. The sodium gate opens (the ativation gate) allowing sodium into the cell.  The cell depolarizes becoming more positive. Then repolarization phase happens where the sodium gate closes (inactivation gate) stopping sodium from going into the cell, and the potassium gate opens allowing it to go out of the cell. The cell becomes more negative. Late repolarization phase (hyperpolarization phase) the activation gate closes and the inactivation gate opens, while the potassium gate is still open.  then returns to rest where both channels are closed.
  25. Absolute Refractory Period
    • During depolarization phase and most of repolarization phase
    • If a stimulus occurs there would not be an action potential
  26. Relative Refractory Period
    • Last bit of repolarization phase and all of late repolarization phase.
    • If a suprastimulus happens there will be an action potential
  27. Continous Conduction
    • Unmyelinated Axons
    • Domino Affect- Positive charge opens the next channel, which opens the next (similar to diffusion)
  28. Saltatory Conduction
    • Faster of two methods
    • Opposite charges attract the action potential to the next channel
    • Myelinated axons (acts as insulation)
    • Gets to the next channels faster (Not having to go to as many)
  29. Factors that influence the spped of conduction
    • Leakiness of Membrane: Membrane resistance (Low or high) More leaky= Slower Myelin or Unmyelinated affects the leakiness
    • Size (Diameter) of Axons: Internal Resistance- Bigger (Thicker) axons conduct faster because of the less internal resistance (friction)
  30. Transmission Across a Synapse
    • 1) Electrical Synapse- Has gap Junction, The changes in transmembrane potential of one cell produces a local current that affect other cells
    • 2) Chemical Synapse- Cells are not directly coupled, Action potential may or may not release enough neuraltransmitter to reach threshold
  31. Chemical Synapse
    • Excitatory Neurotransmitters: EPSP Graded potential that depolarizes the post-synaptic cell (More likely to cause an action potential)
    • Inhibatory Neurotrasmitters: IPSP Graded potential that hyperpolarizes the post-synaptic cell (Less likely to cause an action potential)
  32. Neurotransmitters
    • 1) Acetlycholine (Ach): Can be IPSP or EPSP depending on the situation (Receptors- Nictonic & Muscarinic)
    • 2) Norepinephrine (NE): Can be IPSP or EPSP depending on receptors Alpha and Beta- 1=Excitatory- 2=Inhibatory
  33. Gradient Potential
    Adding them all up you get a net effect, if it reaches threshold you get an action potential
  34. Integrating Information (Neurons)
    • Spatial Summation: Recieves input from multiple neurons at about the same time (Adding waves together)
    • Temporal Summation: Receives repeated input from a single neuron happening close together (can't be chance of dispation)
  35. Collection Information (Neurons by classifying sensory receptors criterion)
    • Source/ Location of Stimulus: Exteroreceptors (external stimulus), Interorecptors (internal stimulus), Proprioreceptors (body position)
    • Type of Stimulus: Mechanoreceptors, Chemorecptors, Thermoreceptors, Nociceptors (pain), Osmoreceptors (osmotic pressure)
  36. Function of Muscles
    Convert chemical energy to mechanical energy in order to produce force
    • Z-Discs: Anchor for thin filament
    • I- Band: Light in color- thin filament only
    • A- Band: Dark in color- Represents length of thick filament
    • H-Zone: Lighter in color- Located in the A-Band- Contains only thick filament
  37. Contractile proteins
    • Actin: Main Component of filament
    • Myosin: Only component of thick filament
  38. Regulatory Proteins
    • Tropomyosin: Sits in the grooves of thin filament blocking the myosin binding sites of actin
    • Troponin: Holds tropomyosin in place when the muscle is in rest
  39. Muscle Contraction
    • 1) Excitation of muscle cells (Surface of muscle cell)
    • 2) Excitations- Contraction Coupling
    • 3)Contraction Cycle
  40. As the action potential travels down the change in membrane potential causes the Calcium channels to open. The calcium ions cause exocytosis of Ach(neurotransmitter) which then binds the the ligand-gated sodium channels which will cause depolarization sinding the action potential along the membrane
  41. Excitation-Cotraction Coupling
    • Muscle action potential triggers the release of calcium channel from the SR (sarcoplasmic Reticulum), calcium leaves the SR and diffuses throughout the muscle cell
    • Then the calcium binds to the Troponin, the troponin changes shape which makes them stop holding the tropomyosin in the gooves of thin filament
    • By the tropmyosin no longer held in the grooves it exposes the myosin binding sites of actin
  42. Contraction Cycle
    • Cross-bridge formation: myosin head binds to the myosin binding sites of actin creating a bridge between thick and thin filaments
    • Powerstroke: Myosin head rotates toward the center of the sarcomere
    • Detachment: ATP binds to myosin head which causes myosin to release actin
    • ATP Hydrolysis: Myosin head breaks ATP into ADP + Pi and then returns to normal position.
  43. Force is Regulated (Amt)
    • Differential Recruitment of motor units
    • Frequency of stimulation-Twitch contraction (Stair effect)
    • Length of Sarcomeres- Long= no crossbridge, Short= no room to shorten
  44. Energy for Contraction (ATP only lasts for a few secs)
    Energy to Regenerate ATP
    • Phosphocreatine (PCr): Only have addition 10-12 secs
    • Anaerobic Metabolism/Respiration: Glucose -> 2 Pyruvate (Lactate) + 2ATP   No oxygen, Only additional  30-45 secs
    • Aerobic Metabolism/Respiration: Glucose +O2 -> CO2 + H2O = 36 ATP   W/ Oxygen
  45. Types of Skeletal Muscle Fibers (Based on speed of twitch and the preferred source of energy type)
    • Slow Oxidative Fibers: Type 1, SO
    • Fast Oxidative-Glycolytic Fibers: Type 2, FOG
    • Fast Glycolytic Fibers: Type 2b, FG
  46. SO
    • Speed of Twitch: Slow
    • Preferred Source of Energy: Aerobic
    • Amount of Myoglobin: More
    • # of Mitochondria: More
    • Stored Glycogen: Less
    • Fatigue Resistance: High
  47. FG
    • Speed of Twitch: Fast
    • Preferred Source of Energy: Anaerobic
    • Amount of Myoglobin: Less
    • # of Mitochondria: Less
    • Stored Glycogen: More
    • Fatigue Resistance: Low
  48. Muscle Fatigue
    Inability to maintain force during prolonged contraction
  49. Types of Muscle Fatigue
    • Central Fatigue (Phychological fatigue): Muscle is capable but the brain is not asking. All in your head, CNS or Motor Neuron
    • Peripheral Fatigue (Physiological fatigue): Muscle is not capable.  Neural Muscular or Muscle Cell
  50. Problems in conducting signal in T-tubules= Electrolyte Imbalance
    If the amt of potassium increases the the cell is depolarized, which makes it harder to repolarize, and the channel get stuck closed.