TAMU Biol 319 Lab 7 2025

What is the anatomy of muscle spindles? 3-10 modified skeletal muscle muscle fibers 4 - -how many neurons does the myotatic stretch employ? Activates skeletal muscle - -what is a somatic reflex? Alpha efferent fiber to extrafusal muscle fibers - -identify number 11 Alpha motor neuron (effector) stimulates extensor muscle to contract - -what is the fourth step of a monosynaptic reflex? Anulospiral endings - -identify number 1 Artificial reflex where sensory axon synapses in spinal cord with interneuron - -what reflex helps to maintain upright posture? Breathing, maintaining posture, controlling viscera, avoiding pain - -what do inborn reflexes allow us to do? Can cause spindle to stretch and become more sensitive or inhibit gamma neurons to cause the spindle to loosen and become insensitive - -what can the brain do with regard to gamma neurons? Capsule (connective tissue) - -identify number 5 Causes anulospiral and flower spray endings to fire at an increased rate - -what happens when the muscle's spindle is stretched? Causes muscles to relax in circumstances of high tendon tension which aids in preventing tendons from tearing when excess stretching force is applied - -how does the polysynaptic tendon reflex work? Central nervous system - -what is the integration center for most reflexes? Ciliary ganglion - -identify number 8 Connective tissue sheaith - -within a muscle spindle, the intrafusal muscle fibers are enclosed by what? BIOL319 BIOL319 BIOL319 Controlling inhibition and brain preventing extraneous movements of the body by sending out inhibitory singles to prevent uncoordinated movements - -how are many biologial processes regulated? Controls visceral effectors such as smooth muscle, cardiac muscle, or gland - -what is an autonomic reflex? Convey information about muscle length or the amount of stretch - -what is the purpose of muscle spindles in skeletal muscle? Convey information about tendon tension to inform the central nervous system for the regulation of these reflexes - -what is the purpose of the golgi tendon organs? Damage in brain or spinal cord from stroke - -what would an exaggerated reflex indicate? Damage of peripheral nerves such as from neurosyphilis or chronic diabetes mellitus - what would an absent reflex indicate? Determine if motor and sensory connections between the spinal cord and thigh muscles are functioning - -what is the patellar knee-jerk reflex test used to do? Do not involve higher brain centers to function but can help to receive communication - what are spinal reflexes? During difficult or fast movements such as balancing on one foot - -when does the brain increase gamma motor output? Edinger-westphal nucleus - -identify number 6 Efferent motor neuron to contracting muscle is inhibited and efferent motor neuron to antagonistic muscle is activated so it will contract - -what is reciprocal activation? Endings of large axons which wrap around the center of the muscle spindle and are stimulated by the degree of stretch and rate of stretch - -what are anulospiral endings? Enhance postural support during withdrawal of affected limb from painful stimulus - what is the crossed extension reflex? Extensor contracts and flexor relaxes in contralateral leg to support weight - -what is the second step of a polysynaptic reflex? Extrafusal muscle fibers - -identify number 9 Flexor contract and extensor relaxes to withdraw foot - -what is the first step of a polysynaptic reflex? BIOL319 BIOL319 Flower spray endings - -identify number 2 For both males and females, reaction time shortens from infancy into late 20s then increases slowly until the 50s and 60s and then lengthens faster as the person get into his 70s and beyond - -what is age in relation to reaction time? Gamma efferent fiber to muscle spindle - -identify number 3 Gamma efferent fibers - -what maintains tension in intrafusal fibers? Gamma motor neurons can also cause the intrafusal fiber ends to contract which will stretch spindle's middle - -what is internal stretch? Generally, reaction times are faster when the subject has been warned that a stimulus will arrive soon - -what are warnings in relation to reaction time? Help coordinate smooth movements of skeletal muscle groups - -what is the purpose of stretch and tendon reflexes? High degree of motion such as to toss a football - -when does the brain decrease and inhibit the stretch reflexes? Inborn and learned - -what are the two types of reflexes? Increase reaction time significantly especially in younger individuals - -what is distraction? Infants will normally display this until 1 year of age because the nervous system is not completely myelated - -what is the relationship between infants the babinski sign? Instead of toes flexing the big toe dorsiflexes and other toes laterally fan - -what is the babinski sign? Integration center stimulated - -what is the third step of a monosynaptic reflex? Integration center will include a few synapses and interneurons - -what is a polysynaptic relfex? Intrafusal muscle fibers - -identify number 10 Intrafusal muscle fibers - -what are the fibers within a muscle spindle called? Involve motor activity on the same sid