AnswersDriveA motor neuron carries the message from the central nervous system to the effector. In a knee-jerk reflex arc the sensory neuron directly connects to the motor neuron in the spinal cord. This is called a simple reflex arc. from the spindle (receptor) to where it connects with the motor neuron in the spinal cord.
What is the function of the knee jerk reflex?
The primary purpose of the patellar reflex, which is the stretch reflex of the quadriceps femoris muscle in your anterior thigh, is to prevent the stretching of the quadriceps. The patellar reflex is illustrated in Figure 2. The patellar tendon attaches the quadriceps muscle to the tibia bone of the lower leg.
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What does knee jerk reflex mean?
knee-jerk reflex. A sudden involuntary forward movement of the lower leg that can be produced by a firm tap to the tendon located just below the kneecap.
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What is the minimum number of neurons that can be involved in a reflex?
What is the minimum number of neurons that can make up a "reflex arc"
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What would the neurons be that make up a reflex arc? There must be at least one sensory neuron and at least one motor neuron.
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What would the neurons be that make up a reflex arc? There must be at least one sensory neuron and at least one motor neuron.
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What does all reflexes have in common?
Reflexes are set motor responses to specific sensory stimuli. All reflexes share three classical characteristics: they have a sensory inflow pathway, a central relay site, and a motor outflow pathway. Together, these three elements make up the reflex arc.
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How does your reflexes work?
The simplest circuits in the nervous system are reflexes. A reflex is an automatic reaction to a stimulus. A stimulus is something that causes an action. In a simple reflex, a neuron brings information about a stimulus to the brain or spinal cord and connects with a motor neuron.
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How is information passed through the synapse?
The chemical diffuses across the gap makes the next neurone transmit an electrical signal. This triggers the nerve-ending of a neuron to release chemical messengers called neurotransmitters. These chemicals diffuse across the synapse (the gap) and bind with receptor molecules on the membrane of the next neuron.
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How do nerve impulses travel?
When a nerve impulse reaches the end of an axon, the axon releases chemicals called neurotransmitters. Neurotransmitters travel across the synapse between the axon and the dendrite of the next neuron. Neurotransmitters bind to the membrane of the dendrite.
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Which cranial nerve is responsible for the pupillary reflex?
The pupillary light reflex neural pathway on each side has an afferent limb and two efferent limbs. The afferent limb has nerve fibers running within the optic nerve (CN II). Each efferent limb has nerve fibers running along the oculomotor nerve (CN III). The afferent limb carries sensory input.
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What type of reflex causes blinking?
The corneal reflex, also known as the blink reflex, is an involuntary blinking of the eyelids elicited by stimulation of the cornea (such as by touching or by a foreign body), though could result from any peripheral stimulus.
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How does the nervous system work to help with reflexes?
A reflex action often involves a very simple nervous pathway called a reflex arc. A reflex arc starts off with receptors being excited. They then send signals along a sensory neuron to your spinal cord, where the signals are passed on to a motor neuron. As a result, one of your muscles or glands is stimulated.
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What is the function of the stretch reflex?
The stretch reflex (myotatic reflex) is a muscle contraction in response to stretching within the muscle. It is a monosynaptic reflex which provides automatic regulation of skeletal muscle length. When a muscle lengthens, the muscle spindle is stretched and its nerve activity increases.
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Is the knee jerk reflex Monosynaptic or Polysynaptic?
monosynaptic reflex A simple reflex that involves transmission of information from a sensory neuron to the appropriate motor neuron across a single synapse in the spinal cord. The knee-jerk reflex action is an example of a monosynaptic reflex (see stretch reflex). Compare polysynaptic reflex.
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Why is it important to have reflexes?
The Importance of Reflexes - Parents With Purpose. A reflex is an involuntary motor response to a sensory stimulus. Reflexes perform many jobs for our central nervous system. They protect us from danger, they help us move our body, they help us see, etc.
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What do you mean by reflex action?
A reflex, or reflex action, is an involuntary and nearly instantaneous movement in response to a stimulus. The reflex is then an automatic response to a stimulus that does not receive or need conscious thought.
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What is the effector muscle of the knee jerk reflex?
A monosynaptic reflex extension of the leg resulting from a sharp tap on the patellar tendon. It helps maintain and upright position. It's effector muscles are located in the quadriceps femoris. It's connected to the withdrawal reflex.
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What part of the reflex arc carries out the response?
Sensory cells carry afferent impulses to a central interneuron, which makes contact with a motor neuron. The motor neuron carries efferent impulses to the effector, which produces the response. Three types of neurons are involved in this reflex arc, but a two-neuron arc,…
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What is the effector of the patellar reflex?
The quadriceps femoris is the effector muscle of the patellar reflex. The dorsal roots of spinal nerves contain the axons of the motor neurons. The normal patellar reflex response involves extension of the leg at the knee joint.
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What is a neural reflex?
A reflex arc is a neural pathway that controls a reflex. In vertebrates, most sensory neurons do not pass directly into the brain, but synapse in the spinal cord.
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What are the basic components of a reflex?
There are two types of reflex arcs:the autonomic reflex arc, affecting inner organs, and the somatic reflex arc, affecting muscles. When a reflex arc consists of only two neurons, one sensory neuron, and one motor neuron, it is defined as monosynaptic. Monosynaptic refers to the presence of a single chemical synapse.