Definition Paralysis is the loss of the power to move a part of the body due to injury or disease of the nerves that supply the muscles involved in moving that part of the body. The key points in this definition are firstly that paralysis refers to a loss of movement rather than just weakness‚ and secondly that the problem originates in the nerves to the muscles rather than in the muscles themselves. The severity of the paralysis is indicated in medical terminology by the word endings:
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meaning that it will generate an electrical impulse‚ or inhibitory‚ meaning that it will prevent the neuron from firing an electrical impulse. A neuron receives thousands of input signals from its dendrites‚ but whether the neuron is excited enough to the point it will generate an electrical impulse depends on the sum of the inhibitory and excitatory signals. The resting potential of a neuron is -70 MV‚ and the threshold to activate an electrical impulse (action potential) is – 55
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Week 2 Reading Summary : Chap 1-3 Chapter 1 Anatomy: studies the structure of body parts and their relationship to one another. Can be seen‚ felt‚ examined. Physiology: concerns the function of the body in other words‚ how the body parts work and carry out their life-sustaining activities Complementary of structure and function Function reflect structure‚ what a structure can do depends on is specific form Levels of structural organization: Cells – smallest living unit
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coordination‚ precision‚ and accurate timing. 5. Brain Stem- the posterior part of the brain‚ adjoining and structurally continuous with the spinal cord. The brain stem provides the main motor and sensory innervation to the face and neck via the cranial nerves. 6. Medulla- a portion of the hindbrain that controls autonomic functions such as breathing‚ digestion‚ heart and blood vessel function‚ swallowing and sneezing. 7. Pons- includes tracts that conduct signals from the cerebrum down to the cerebellum
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the original stimulus. 3. The axon terminal is the nerve ending. The nodes speed up the message. The myelin sheath is an insulating membrane. The axon carries impulses away from the cell body. The cell body is the largest part of a typical neuron. The dendrites carry impulses from the environment or from other neurons toward the cell body. The nucleus is the control center of the cell. 4. A synapse is location at which a
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The Action potential • Transmission is due to movement of ions (Na+ and K+) across nerve cell membrane • Na+ found mainly outside cells – tends to diffuse inwards • K+ found mainly inside cells – tends to diffuse outwards • Stimulation of neurone changes the membrane permeability to ions • Depolarisation occurs as Na+ floods into cell through sodium channels setting up the nerve impulse (very fast) • Impulse travel is one way from stimulus • Then K+ flows out of cell (repolarisation) and the
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symptoms include dry mouth‚ irritability‚ unusual weight loss‚ and extreme hunger. Over time‚ the high blood glucose levels present‚ as a result of diabetes‚ may cause serious complications‚ such as damage blood vessels and nerve cells‚ leading to damaged eyes‚ nerves and kidneys and an increased risk of heart attack‚ stroke‚ impotence‚ and foot problems. Another example is hypertension. Hypertension is the term used to describe high blood pressure. Blood pressure is a measurement of
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The Oculomotor nerve functions in opening and moving the eye‚ constricts and focuses the pupil. It originates in the midbrain and passes through the superior orbital fissure of the sphenoid bone. TheTrochlear nerve causes the superior oblique to contract‚ thereby moving the eyeball inferiorly and laterally (Primal). Passes through the sphenoid bone through the superior orbital fissure. The Trigeminal nerve is composed of the ophthalmic‚ maxillary‚ and mandibular nerves. All three serve different
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conversion of stimulus energy into neural impulses. The stimulus energy is in the form of light energy (waves)‚ and this light energy enters the eye. After passing through such parts as the iris and the lens‚ the light energy reaches the retina‚ where sense receptors are located and where transduction occurs. Rods and cones are the eye’s sense receptors that produce chemical changes that generate neural signals. These neural signals get relayed to the optic nerve‚ which leads to the brain. Another example
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position/posture‚ generates heat 2. Location: on top of/attached to bones (skeletal) AND in certain organs (smooth) 3. Organs: skeletal muscles and smooth muscle‚ tendons and ligaments Nervous System: 1. Function: generates Action Potentials (nerve impulses)‚ regulates body activities‚ detects changes in body chemistry/internal and external environment‚ interprets changes‚ responds to AP’s by causing
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