ap test 7

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  1. Classes of joints
    based on major connective tissue type that binds bones
  2. three types of structural bones
    • Fibrous
    • Cartilaginous
    • Synovial
  9. Fibrous Joints: Sutures
    • Opposing bones interdigitate.
    • Periosteum of one bone is continuous with the periosteum of
    • the other.
    • Sutural ligament: two periostea plus dense, fibrous, connective tissue between.
    • In adults may ossify completely: synostosis.
    • Fontanels: membranous areas in the suture between bones. Allow change in shape of head during birth and rapid growth of the brain after birth.
    • Joined by hyaline cartilage
    • Little or no movement
    • Some are temporary and are replaced by synostoses
    • Some are permanent
    • Examples: Epiphyseal plates, sternocostal
    • Fibrocartilage uniting two bones
    • Slightly movable
    • Examples: symphysis pubis, between the manubrium sternum and the body of the sternum, intervertebral discs
  13. Synovial Joints
    • Contain synovial fluid
    • Allow considerable movement
    • Most joints that unite bones of appendicular skeleton reflecting greater mobility of appendicular skeleton compared to axial
    • Complex
  14. Synovial Joints
    Articular cartilage:
    hyaline; provides smooth surface
  15. Synovial Joints
    Joint cavity
    synovial; encloses articular surfaces
  16. Synovial Joints
    • Fibrous capsule: dense irregular connective tissue, continuous with fibrous layer of the periosteum.
    • Portions may thicken to form ligaments.

    Synovial membrane and fluid: membrane lines inside of joint capsule except at actual articulation of articular cartilages. Thin, delicate. Sometimes separated from fibrous capsule by areolar C.T. and fat, sometimes merged with fibrous
  17. Synovial Joints
    Synovial Fluid
    complex mixture of polysaccharides, proteins, fat and cells.
  18. Proprioception:
    Nerves in capsule help brain know position of joints
  19. Bursae
    Pockets of synovial membrane and fluid that extend from the joint. Found in areas of friction
  20. Ligaments and tendons
  21. Menisci
    fibrocartilaginous pads in knee
  22. Tendon Sheaths
    Synovial sacs that surround tendons as they pass near or over bone
  23. Types of synovial joints
    occuring around one axis
  24. types of synovial joints
    occuring around two axes at right angles to each other
  25. multiaxial:
    occuring around several axes
  26. Plane or gliding joints
    • Uniaxial. some rotation possible but limited by surrounding structures
    • Example: intervertebral
  27. Saddle Joints
    • Biaxial
    • Example: thumb (carpometacarpal pollicis)
  28. Hinge Joints
    • Uniaxial
    • Convex cylinder in one bone; corresponding concavity in the other
    • Example: elbow, interphalangeal
  29. Pivot joints
    • Uniaxial. Rotation around a single axis.
    • Cylindrical bony process rotating within a circle of bone and ligament
    • Example: articulation between dens of axis and atlas (atlantoaxial), proximal radioulnar, distal radioulnar
  30. Ball-and-Socket Joints
    • Multiaxial
    • Examples: shoulder and hip joints
  31. Ellipsoid (Condyloid)
    • Modified ball-and-socket; articular surfaces are ellipsoid
    • Biaxial
    • Example: atlantooccipital
  32. Types of Movement
    Angular (4)
    • flexion and extension
    • hyperextension
    • plantar and dorsiflexion
    • abduction and adduction
  33. Types of Movement
    Circular (3)
    • Rotation
    • Circunduction
    • Pronation and Supination
  34. Plantar Flexion
    Standing on toes
  35. Dorsiflexion
    foot lifted toward shin
  36. Abduction:
    Movement of a limb away from a bodies midline
  37. adduction:
    Movement of a limb toward the midline of the body
  38. Circumduction:
    Movement of a limb so that it describes a cone
  39. Rotation:
    Turning of a structure on its axis
  40. Supination
    Rotation of the forearm so the palm faces anteriorly
  41. Pronation
    Rotaion of the forearm so palm faces posteriorly
  42. Elevation:
    Move a structure superior
  43. Depression:
    moves a structure inferioir
  44. Protraction:
    Gliding motion anteriorly
  45. Retraction:
    moves structure back to anatomic position or further
  46. Excursion
    • lateral: moving mandable to the right or the left
    • medial: return mandable to the midline
  47. opposition
    movement of the thumb and little finger toward eachother
  48. reposition
    return to anatomical position
  49. inversion:
    turning the ankle so the plantar surface of foot faces medially
  50. eversion:
    Turning the ankle so the plantar surface of the foot faces laterally
  51. Functions of the Nervous System
    • Receiving sensory input. Monitor internal and external stimuli
    • Integrating information. Brain and spinal cord process sensory input and initiate responses
    • Controlling muscles and glands
    • Maintaining homeostasis. Regulate and coordinate physiology
    • Establishing and maintaining mental activity. Consciousness, thinking, memory, emotion
  52. Neuroglia
    • Support and protect neurons
    • Support cells of the brain, spinal cord and nerves
    • Nourish, protect, and insulate neurons
  53. Neurons or nerve cells
    receive stimuli and transmit action potentials
  54. Organization
    • Cell body or soma
    • Dendrites: input
    • Axons: output
  55. Neuroglia of the CNS: Astrocytes
    • Processes form feet that cover the surfaces of neurons and blood vessels and the pia mater.
    • Regulate what substances reach the CNS from the blood (blood-brain barrier).
    • Produce chemicals that promote tight junctions to form blood-brain barrier
    • Blood-brain barrier: protects neurons from toxic substances, allows the exchange of nutrients and waste products between neurons and blood, prevents fluctuations in the
    • composition of the blood from affecting the functions of the brain.
    • Regulate extracellular brain fluid composition
  56. Neuroglia of the CNS: Ependymal Cells
    • Line brain ventricles and spinal cord central canal.
    • Specialized versions of ependymal form choroid plexuses.
    • Choroid plexus within certain regions of ventricles. Secrete cerebrospinal fluid.
    • Cilia help move fluid thru the cavities of the brain.
  57. Neuroglia of the CNS: Microglia
    • specialized macrophages. Respond to inflammation, phagocytize necrotic tissue, microorganisms, and foreign
    • substances that invade the CNS
  58. Neuroglia of the CNS: Oligodendrocytes
    form myelin sheaths if surrounding axon. Single oligodendrocytes can form myelin sheaths around portions of several axons.
  59. Neuroglia of the PNS
    • Schwann cells
    • Wrap around portion of only one axon to form myelin sheath.
    • Wrap around many times.
    • During development, as cells grow around axon, cytoplasm is squeezed out and multiple layers of cell membrane wrap the axon.
    • Cell membrane primarily phospholipid
  60. Myelinated axons
    • Myelin protects and insulates axons from one another, speeds transmission, functions in repair of axons.
    • Not continuous
    • Nodes of Ranvier
    • Completion of development of myelin sheaths at 1 yr.
    • Degeneration of myelin sheaths occurs in multiple sclerosis and some cases of diabetes mellitus
  61. Unmyelinated axons:
    • rest in invaginations of Schwann cells or oligodendrocytes.
    • Not wrapped around the axon.
  62. Satellite cells:
    surround neuron cell bodies in sensory ganglia, provide support and nutrients
  63. Nervous Tissue: Neurons
    Neurons or nerve cells have the ability to produce action potentials
  64. Cell body (soma):
    contains nucleus
  65. Axon:
    cell process; conducts impulses away from cell body; usually only one per neuron
  66. Dendrite:
    cell process; receive impulses from other neurons; can be many per neuron
  67. Types of Neurons
    Action potentials toward CNS
  68. Types of Neurons
    Action Potential away from CNS
  69. Types of Neurons
    within CNS from one neuron to another
  70. Types of Neurons
    Most neurons in CNS; motor neurons
  71. Types of Neurons
    Sensory in retina of the eye and nose
  72. Types of Neurons
    single process that divides into two branches. Part that extends to the periphery has dendrite-like sensory receptors
  73. Concentration Differences Across the Plasma Membrane
    • There is a high concentration of Na+ and Cl- ions outside and high concentration of K+ and proteins on inside.
    • There is a steep concentration gradient of Na+
    • and K+, but in opposite directions
  74. Permeability Characteristics of the Plasma Membrane
    • Cytoplasmic anions can not escape due to size or charge (phosphates, sulfates, small organic acids, proteins, ATP, and RNA)
    • Gated ion channels open and close because
    • of some sort of stimulus. When they open, they change the permeability of the cell membrane.
  75. Electrical Signals
    • Cells produce electrical signals called action potentials
    • Transfer of information from one part of body to another
    • Electrical properties result from ionic concentration differences across plasma membrane
    • and permeability of membrane
  76. Establishing the Resting Potential
    • Potassium ions (K+) have the greatest influence on RMP
    • Resting membrane potential (RMP): charge difference across the plasma membrane -70 mV in a resting, unstimulated neuron
    • Negative value means there are more negatively charged particles on the inside of the membrane than on the outside
    • Na+/K+ pumps out 3 Na+ for every 2 K+ it brings in
    • Works continuously to compensate for Na+ and K+ leakage, and requires great deal of ATP
    • 70% of the energy requirement of the nervous system Necessitates glucose and oxygen be supplied to nerve tissue (energy needed to create the resting potential)
  77. Changes in Resting Membrane Potential: Na+
    • Na+ membrane permeability.
    • Change the concentration of Na+ inside or outside the cell, little effect because gates remain closed.
    • But open gates (like when ACh attaches to receptors), Na+
    • diffuses in, depolarizing the membrane.
  78. Graded Potentials
    • Results from:
    • Ligands binding to receptors
    • Changes in charge across membrane
    • Mechanical stimulation
    • Temperature changes
    • Spontaneous change in permeability
    • Graded
    • Magnitude varies from small to large depending on stimulus strength of frequency
    • Spread(are conducted) over the plasma membrane in a decremental fashion: rapidly decrease in magnitude as they spread over the surface of the plasma membrane.
    • Can cause generation of action potentials
  79. Action Potentials
    • When threshold is reached (-55mV), neuron ‘fires’ and produces an action potential
    • More and more Na+ channels open in in the trigger zone in a positive feedback cycle creating a rapid rise in membrane voltage
    • When rising membrane potential passes 0 mV, Na+
    • gates are inactivated
    • Begin closing
    • When all closed, the voltage peaks around +35 mV
    • Membrane now positive on the inside and negative on the outside
    • Polarity reversed from RMP - depolarization
    • By the time the voltage peaks, the K+
    • gates are fully open
    • K+ repelled by the positive intracellular fluid now exit the cell
    • Their outflow repolarizes the membrane
    • Shifts the voltage back to negative numbers returning toward RMP
    • K+ gates stay open longer than the Na+
    • gates
    • Slightly more K+ leaves the cell than Na+ entering
    • Drops the membrane voltage 1 or 2 mV more negative than the original RMP – negative overshoot – hyperpolarization or afterpotential
    • Na+ and K+ switch places across the membrane during an action potential
  80. Action Potentials
    • —An action potential follows an all-or-none law
    • If threshold is reached, neuron fires at its maximum voltage
    • If threshold is not reached it does not fire
    • Nondecremental: do not get weaker with distance
    • Irreversible: once started goes to completion and cannot be stopped
  81. Threshold
    • Threshold stimulus: causes a graded potential that is great enough to initiate an action potential.
    • Subthreshold stimulus: does not cause a graded potential that is great enough to initiate an action potential.
  82. The Refractory Period
    • During an action potential and for a few milliseconds after, it is difficult or impossible to stimulate that region of a neuron to fire again.
    • Refractory period: the period of resistance to stimulation
    • Two phases of the refractory period
    • —Absolute refractory period
    • No stimulus of any strength will trigger AP
    • —As long as Na+ gates are open
    • —From action potential to RMP
    • —Relative refractory period
    • Only especially strong stimulus will trigger new AP
    • K+ gates are still open and any affect of incoming Na+ is
    • opposed by the outgoing K+
    • Refractory period is occurring only at a small patch of the neuron’s membrane at one time
    • Other parts of the neuron can be stimulated while the small part is in refractory period
  83. Signal Conduction in Unmyelinated Fibers
    • Threshold graded current at trigger zone causes action potential
    • Action potential in one site causes action potential at the next location. Cannot go backwards because initial action potential
    • site is depolarized yielding one-way conduction of impulse.
  84. Saltatory Conduction Myelinated Fibers
    • Saltatory conduction: the nerve signal seems to jump from node to node
    • Much faster than conduction in unmyelinated
    • fibers
  85. Speed of Conduction
    • Faster in myelinated than in non-myelinated
    • In myelinated axons, lipids act as insulation forcing ionic currents to jump from node to node
    • In myelinated, speed is affected by thickness of myelin sheath
    • Diameter of axons: large-diameter conduct more rapidly
    • than small-diameter. Large have greater surface area and more voltage-gated Na+ channels
  86. Synapses
    • —A nerve signal can go no further when it reaches the end of the axon
    • Triggers the release of a neurotransmitter
    • —Stimulates a new wave of electrical activity in the next cell across the synapse
    • Synapse between two neurons
    • 1st neuron in the signal path is the presynaptic neuron
    • Releases neurotransmitter
    • —2nd neuron is the postsynaptic neuron
    • —Responds to neurotransmitter
  87. Chemical Synapses
    • Components
    • Presynaptic terminal
    • Synaptic cleft
    • Postsynaptic membrane
    • Neurotransmitters released by action potentials in presynaptic terminal
    • Synaptic knob of presynaptic neuron contains synaptic vesicles containing neurotransmitter
    • Action potential causes Ca2+ to enter cell that causes neurotransmitter to be released from vesicles
    • Diffusion of neurotransmitter across synapse
    • Postsynaptic membrane: when ACh binds to receptor, ligand-gated Na+ channels open. If enough Na+ diffuses
    • into postsynaptic cell, it fires
Card Set:
ap test 7
2012-05-01 02:05:17
ap test

ap test 7 cp 8 and 11
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