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A & P 01 D
CanColl May12 MCQ AP1 D
Question | Answer |
---|---|
Name the types of neurolgia found in the CNS | astrocytes, oligodendrocytes, microglia and ependymal cells |
name the types of neuroglia found in the PNA | schwann cells and satellite cells |
Function of oligodendrocytes in CNS | most common cells, produce myelin sheaths in CNS |
function of microglia in CNS | phagocytic |
function of ependymal cells in CNS | create cerebrospinal fluid CSF |
what are myelin sheaths made of | lipid and protein wrapping of the nerve axons |
function of the schwann cells in PNS | creat myelin sheaths in PNS |
function of myelin sheath | electrically insulates the axon of a neuron and increases the speed of nerve impulse conduction. |
saltatory conduction | the movement of an action potential along a myelinated sheath - jumps from node to node |
most common type of disease affecting the myelin sheath | Multiple Sclerosis MS |
def: ganglia | a term for nerve bodies in the PNS that are clustered together |
def: tract | a bundle of nerve fibres without any connective tissue in the CNS |
def: nerve fibres | general term for either dendrite or axon - but usually refers to axons |
the axon hillock is also known as the | trigger zone |
what is between the sections of myelin sheath | nodes of ranvier |
what direction does information flow within a neuron | from dendrite to axon |
def: action potential | a wave of negativity that self-propagates along the membrane fo a neuron or mm cell - it is a rapid change that involves a depolarization then a repolarization |
an action potential is also called a | nerve impulse |
Def: threshold | the critical level - about -55 mV - that will create an action potential to arisse at the trigger zone |
steps of an action potential | 1. depolarization (Na+ into the cell) becomes less neg 2.repolarization (K+ flows out) |
absolute refractory period | time during which a second action potential cannot be initiated |
relative refractory period | time during which a second action potential can be initiated but only iwth a suprathreshold stimulus |
Continuous conduction vs saltatory | continuous - nonmyelinated axon - saltatory - myelinated axon - leaps from node to node |
Types of nerve fibres | A fibres - myelinated, largest diameter, B fibres - mylenated, medium diameter, C fibres nonmyelinated, small diameter |
what is the name of the neurotransmitter released by the presynaptic vesicles of the neuromuscular junction? | acetylcholine ACh |
what are the end points that define the extent of a sarcomere? | The sarcomere extends from on Z disk to the next Z disk |
What is the M line in a sarcomere? | it represents the centre of the sarcomere |
classification of muscles tissues | skeletal - striated/voluntary, cardiac - striated/nonvoluntary, smooth - nonstriated/nonvoluntary |
characteristics of muscle tissue | contractility, extensibility, conductivity, elasticity |
Def: motor unit | the motor neuron plus all the skeletal fibres that it stimulates |
in a sarcomere - the thin filaments are mainly composed of | actin |
the thick filaments within a sarcomere are composed of | myosin |
within a sarcomere - the A band is | seen as a darker area - consisting mostly of thick filaments adn the overlapping potions of thin filaments |
within a sarcomere - the I band is | less dense, containing the rest of the thin filamens and no thick filaments |
within a sarcomere - the H band is | a narrow band in the centre of each A band - that contains thick filaments and no thin filaments |
the actin filaments (thin) contain | myosin binding sites |
the myosin (thick) filaments contain | myosin heads which project toward the thin filaments |
the myosin heads are also called | cross bridges |
During contraction, the myosin heads pull on the thin filaments - causing them to slide in which direction? | toward the center of the sarcomere - the H zone |
Isotonic contraction | the muscle length changes |
isometric contraction | the muscle length does not change |
concentric contraction | the mm length shortens |
eccentric contraction | the mm length increases |
name the five main parts of the CNS | cerebrum, diencephalon, cerebellum, brainstem, spinal cord |
what are associative aka interneurons | they link neurons to neurons |
what are the most common type of neurons in the body - afferent, efferent or associative | associative = 90% of all neurons |
where to graded potential occur | they usually occur in the dendrites and cell body rather than the axons - they are good on for short distance communication |
what are the three stages of inflammation | vasocdilation (inc permeability of vessels), phagocyte migration, tissue repair |
name five substances that cause vasodilation and increased permeability | histamine, kinins, prostaglandins, leukotrines, complement proteins |
which cells arrive first at a site of injury? | neutophils |
second to arrive at the site of injury are the | monocytes |
monocytes become what type of cell | macrophages |
what is the function of a macrophage | phagocytic - they engulf or eat up damaged tissue |
def: cicatrization | formation of scar tissue |