Unit 4 Study Guide Lecture 1 I Muscle movement 1 Muscle contraction 2 Agonist 3 Antagonist 4 Synergist II Human Leverage System 1 Effort muscle pull 2 Resistance object and opposition antagonist 3 Fulcrum middle 4 Moment arm perpendicular distance from fulcrum to the line representing force effort or resistance depending on type of lever 5 Torque force applied to move the lever force moment arm distance i Causes body levers to move ii Resistance torque resistance force at some distance from fulcrum iii Effort torque effort force created by muscle pulling on bone to be moved III Muscle Contractions 1 2 Isometric contractions tension without changing length resistance torque no energy used for length Isotonic contractions muscle produces same amount of tension throughout ROM i Concentric tension while shortening tension resistance example prime movers Least efficient force produced no energy for tension ii Eccentric tension while lengthening resistance tension example antagonist and letting out of a pull up Greatest force produced with low O2 use IV Lever classes 1 First class fulcrum in middle i Long moment arm force favored ii Short moment arm favors speed and range iii Very few in body ex scissors or neck forward back motion 2 Second Class Lever NONE in HUMAN BODY resistance in middle i Effort MA Resistance MA ii Force is favored ex wheel barrel 3 Third Class Lever MOST in HUMAN BOD effort in middle moves i Resistance MA Effort MA ii Force is at a disadvantage ex biceps curl V Muscle Twitch response to a single brief threshold 1 Latent period time from stimulus to start of contraction 2 Contraction period time from onset of contractions to peak muscle tension 3 Relaxation period no force generated 4 Graded contractions of single muscle twitch i Frequency 2 stimuli in rapid succession a Wave summation b Increasing stimulation rate shortens relaxation period increases summation second twitch first a Tetanus fused into small sustained contractions most voluntary muscle contractions and smooth movements not middle relaxation c Strength of stimulus multiple motor units summation or recruitment increases number of muscle fibers thus increasing contraction stronger stimulus more motor units a Treppe stimuli too far apart to cause wave summation staircase effect each full contraction gets stronger VI Muscle Tone continual partial contraction ex posture ready to respond to stimuli 1 Smooth muscles shorter thinner fibers Caveolae holds Ca2 b c poorly developed SR actin and myosin arranged randomly NO troponin NO sarcomeres NO T tubules all in skeletal muscles i Ca from SR and diffuses from extracellular fluid ii Ca interacts with protein Calmodulin and Kinase enzyme on myosin head initiations contraction process a Ca binds to Calmodulin activates Calmodulin activates Kinase Kinase enzyme catalyzes ATP for energy Actin and myosin interact contraction iii More energy efficient iv Stress Relaxation Response smooth muscles contract wen stretched v Neurotransmitter NT then relaxed generates a lot of tension smooth muscles respond to several chemicals stimulated by autonomic NS skeletal muscle ONLY excitatory NT a Excitatory contracts muscle b Inhibitory prevents contraction Lecture 2 I Smooth Muscles 1 Single Unit or Visceral Smooth Muscle ex hollow organs a Outer longitudinal layer b c Rhythmicity contractions Inner circular layer stimulations pacemakers depolarize contraction dilates and shortens organs contraction constricts and elongates organ repeated contractions without external i Gap junctions transmit stimulus to adjacent fibers fibers contract as a single unit d Peristalsis through digestive track wave like series of contractions that move material 2 Multiunit Smooth Muscle occurs in separate fibers and requires stimulation by motor nerves ex iris of eyes arrector pilli airways of lungs II Nervous System Control and communication center of the body 1 Afferent SENSORY towards a structure in CNS brain cord away from receptors in PNS i Visceral afferents info from visceral organs ii Somatic afferents info from body area s muscles joints skin 2 Efferent MOTOR towards muscle or glands away from brain cord i Somatic Nervous System ii Autonomic Nervous System muscles and involuntary glands involuntary conducts impulses to muscles voluntary regulates smooth muscles cardiac 1 Sympathetic and Parasympathetic 3 Functions i Collecting information receptors monitor changes inside and outside the body gathers afferent input ii Evaluating decision making processes and interprets sensory iii Triggers responses activate muscles and glands motor or efferent input output 4 Central Nervous System CNS Integration and command centers i Responses based on past experience reflexes and current conditions 5 Peripheral Nervous System PNS carry sensory info to and motor info from the brain and spinal cord III Supporting Cells 9X more numerous assist segregate and insulate neurons framework and scaffolding PNS myelin sheaths and wrap around nerves phagocytes PNS around cells bodies of neuron in peripheral ganglia 1 Schwann cells 2 Satellite cells and help control chemical environment and fluid with neurons and environment 3 Neuroglia or glial cells CNS framework electrically insulate regulate as i Astrocytes lots of radiating projections with bulbous ends cling to neurons and capillaries living barrier between capillaries and neurons function in neuron metabolism and controlling chemical environment around neurons tissue scavengers phagocytize microorganisms and dead ii Microglia squamous columnar or ciliates shape line iii Ependymal cells central vesicles and form permeable barrier between cerebrospinal fluid and tissue fluid produce myelin sheaths iv Oligodendrocytes small cells that wrap around nerve fibers and IV Neuron Nerve Cells conducting cells Amitotic cant reproduce 1 Cell body usually in CNS i Plasma membrane regulates exchange of materials in and out of cell ii Nucleus contains DNA iii Nucleolus large amount of RNA iv Cytoplasm mitochondria Golgi complex lysosomes rough ER Nissel Bodies NO centrioles 1 Neurofibrils bundles of microtubules and microfilaments that intracellular transport for body to processes v Processes extend form cell body 1 Dendrites Afferent process body to cord high surface area 2 Axon efferent process from cord to cell body a Telodentria b Axolemma branching filaments at distal end plasma membrane of axon myelinated 3 Myelin whitish fatty segmented sheath ex Schwann cells and