Concept explainers
To discuss:
The four criteria for a somatic reflex and their differences.
Introduction:
The spinal nerves are important because the spinal cord sends and receive signals from the body through the spinal nerves. The spinal nerve is composed of large number of nerve fibers or axons and resembles a cord-like appearance. The nervous tissue of the spinal cord is composed of organized cells that involve in the body movements and send the signals to many regions of the body. The spinal cord tracts are stimulatory nerve pathways that pass the information through action potentials.
The reflexes are immediate or automatic involuntary action for response of an external stimulus. The reflex of external stimuli sends the signals through nerves to reach the spinal cord for an immediate action.
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Anatomy & Physiology: The Unity of Form and Function
- In the simplest kind of reflex______, directly signal ________, which act on muscle cells. a. sensory neurons; interneurons b. interneurons; motor neurons c. sensory neurons; motor neurons d. motor neurons; sensory neuronsarrow_forwardThe knee-jerk reflex is often called a stretch reflex because a sharp tap on the patellar ligament stretches the quadriceps femoris, the extensor muscle of the leg. Describe the components and se-quence of events that lead to a “knee jerk.” Why is this reflex sim-pler than most reflex arcs? What is the difference between a reflex arc and a reflex act?arrow_forwardThe central terminals of afferent neurons mediating spinal reflexes are distributed within the spinal cord, so that :-a- all of them terminate in the same spinal segment of their entry to the cordb- all of them terminate on interneuronsc- all of them subserve spinal reflexesd- they provide pathways for divergence of the incoming sensory impulsesarrow_forward
- Each spinal nerve branches into a ventral and dorsal: ganglion  root  tract  plexus  ramusarrow_forwardTrue/False: In a polysynaptic reflex, a sensory neuron synapses directly with a motor neuron.arrow_forwardReflexes can be somatic (as in the knee jerk response) or visceral (as in vomiting). Given that both result in an involuntary motor response, why aren’t they both considered visceral motor?arrow_forward
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- Demyelination of a ventral root would be most likely to produce which of the following?   hypo-reflexia   hyper-reflexia  2. A spinal hemi-section (as is observed in Brown-Sequard syndrome) would be most likely to produce which of the following?   hypertonia   hypotonia below the lesionarrow_forwardThe ventral root of spinal nerves contains___neurons, whereas the dorsal root contains___neuronsarrow_forwardit is not amygdalaarrow_forward
- Human Biology (MindTap Course List)BiologyISBN:9781305112100Author:Cecie Starr, Beverly McMillanPublisher:Cengage Learning