34 Questions
What triggers the activation of a sensory neuron in a muscle spindle?
Muscle stretch
What is the purpose of the stretch reflex?
To prevent overstretching and potential tearing of the tendons and muscle
Where are the dendritic endings of sensory neurons found?
Within the muscle spindles
What type of reflex is the patellar reflex?
Innate reflex
What is the function of the motor neuron in the stretch reflex?
To stimulate muscle contraction
What is the location of the integration of innate reflexes?
The spinal cord
What is the response of the muscle fibers in the stretch reflex?
They contract
What is the relation between the sensory neuron and the motor neuron?
They synapse directly in the CNS
What is an example of a stretch reflex?
Patellar reflex
What is a reflex?
A rapid, automatic motor response to a stimulus
Where are spinal reflexes processed?
In the spinal cord
What is the simplest type of reflex?
Monosynaptic reflex
What type of muscle is controlled by the autonomic nervous system?
Smooth muscle
What is the function of sensory cell clusters called spindles in skeletal muscles?
To monitor muscle length and velocity
What is the primary function of reflexes?
To prevent tissue damage
What is the difference between somatic and autonomic reflexes?
Somatic reflexes are controlled by the somatic nervous system, while autonomic reflexes are controlled by the autonomic nervous system
In a reflex arc, what is the direction of muscle activation relative to the stimulus?
Can be ipsilateral, contralateral, or both
The brain is involved in the reflex arc of spinal reflexes.
False
Monosynaptic reflexes involve multiple synapses within the spinal cord.
False
Somatic reflexes are controlled by the autonomic nervous system.
False
Smooth muscle is controlled by the somatic nervous system.
False
Reflexes can be categorized as either somatic or autonomic.
True
Muscle activation in a reflex can occur on the same side of the body as the stimulus only.
False
Voluntary muscles can be flexed with input from the brain only.
False
Sensory cell clusters referred to as spindles are present in smooth muscles.
False
Muscle spindles are responsible for detecting muscle contraction.
False
The patellar reflex is an example of a learned reflex.
False
The motor neuron fires directly to the brain in the stretch reflex.
False
The patellar reflex is a response to muscle contraction.
False
Sensory neurons synapse directly with motor neurons in the CNS.
True
Innate reflexes are always voluntary responses.
False
Muscle spindles are responsible for muscle contraction.
False
The stretch reflex is a response to muscle shortening.
False
The dendritic endings of sensory neurons are found outside the muscle spindles.
False
Study Notes
Reflexes
- A reflex is a rapid, automatic motor response to a stimulus, occurring over a specific neural pathway called a reflex arc.
- Reflexes prevent damage to tissues by activating a muscle to respond to a stimulus.
- Some reflexes are processed in the brain, while others are processed in the spinal cord, known as spinal reflexes.
Reflex Arc
- A reflex arc involves a sensory neuron, the spinal cord, and a motor neuron.
- The simplest type of reflex is monosynaptic, involving only a single synapse within the spinal cord.
- The sensory neuron directly synapses with a motor neuron in the spinal cord, activating the correct muscle effector.
Types of Reflexes
- Reflexes can be categorized as either somatic or autonomic, depending on whether they are controlled by the somatic or autonomic nervous system.
- Somatic reflexes involve skeletal muscle and are controlled by the somatic nervous system.
- Autonomic reflexes involve smooth muscle and are controlled by the autonomic nervous system.
Somatic Reflexes
- Muscle spindles, present in skeletal muscles, are sensitive to muscle stretch.
- When a muscle stretches, the spindle stretches, and the dendritic endings of sensory neurons detect the stretch, causing activation of a sensory neuron.
- The sensory neuron fires, synapses directly with a motor neuron, and stimulates the muscle fibers to contract, opposing the potentially damaging stretch.
Patellar Knee Jerk Reflex
- The patellar reflex is an example of a stretch reflex, preventing overstretching and potential tearing of tendons and muscle.
- It is an innate reflex, built-in and involuntary, often integrated in the spinal cord, and bypassing the brain completely.
- The patellar reflex is a type of somatic reflex, involving skeletal muscle and controlled by the somatic nervous system.
Reflexes
- A reflex is a rapid, automatic motor response to a stimulus, occurring over a specific neural pathway called a reflex arc.
- Reflexes prevent damage to tissues by activating a muscle to respond to a stimulus.
- Some reflexes are processed in the brain, while others are processed in the spinal cord, known as spinal reflexes.
Reflex Arc
- A reflex arc involves a sensory neuron, the spinal cord, and a motor neuron.
- The simplest type of reflex is monosynaptic, involving only a single synapse within the spinal cord.
- The sensory neuron directly synapses with a motor neuron in the spinal cord, activating the correct muscle effector.
Types of Reflexes
- Reflexes can be categorized as either somatic or autonomic, depending on whether they are controlled by the somatic or autonomic nervous system.
- Somatic reflexes involve skeletal muscle and are controlled by the somatic nervous system.
- Autonomic reflexes involve smooth muscle and are controlled by the autonomic nervous system.
Somatic Reflexes
- Muscle spindles, present in skeletal muscles, are sensitive to muscle stretch.
- When a muscle stretches, the spindle stretches, and the dendritic endings of sensory neurons detect the stretch, causing activation of a sensory neuron.
- The sensory neuron fires, synapses directly with a motor neuron, and stimulates the muscle fibers to contract, opposing the potentially damaging stretch.
Patellar Knee Jerk Reflex
- The patellar reflex is an example of a stretch reflex, preventing overstretching and potential tearing of tendons and muscle.
- It is an innate reflex, built-in and involuntary, often integrated in the spinal cord, and bypassing the brain completely.
- The patellar reflex is a type of somatic reflex, involving skeletal muscle and controlled by the somatic nervous system.
Learn about reflexes, a rapid automatic motor response to a stimulus, including monosynaptic and spinal reflexes, and their neural pathways.
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