human anatomy homework
INSTRUCTIONS:
Read the text and review the tracts below, then answer (a) through (d) under #3. You should have 5 tracts total, worth 3 points each.
SPINAL NERVE TRACTS:
Neurons carry impulses from the brain to the appropriate spinal nerve then to the effector by way of motor tracts. There are a number of motor tracts, both voluntary and involuntary. The voluntary motor path to skeletal muscles is called the pyramidal system (named for the pyramidal cells of the motor cortex). One of the most common pyramidal system tracts, and the one you are responsible for knowing, is the corticospinal tract. The name describes the path from the motor CORTEX to the SPINAL cord and nerves.
Neurons that carry impulses from receptors within the body, up the spinal cord, to the brain do so by means of sensory pathways. There are several sensory pathways depending on the type of stimulus involved, region of the spinal cord that the neurons travel, or the ultimate destination of the path. You will be learning a general sensory pathway that incorporates a couple of these specific tracts.
1. General Motor Tract:
- Review the corticospinal tract presented in the text.
- Study the basic format and the example provided below.
This tract is the same for all of the motor tracings you are responsible for. Variations only occur at the appropriate ramus, appropriate plexus, appropriate spinal nerve, and appropriate skeletal muscle.
FORMAT:
Motor Cortex of cerebrum → Internal Capsule → Mesencephalon → Pon → Medulla → Anterior Horn (synapse) → Anterior Root →Exit appropriate ramus →Appropriate plexus → Appropriate Spinal Nerve (s) → Muscle (synapse)
2. General Sensation Tracts:
- Review the general sensory tract presented in the text.
- Study the basic format and the example provided below.
This tract is the same for all of the sensory tracings you are responsible for. Variations only occur at the appropriate receptor, appropriate spinal nerve, appropriate plexus, and appropriate ramus.
FORMAT:
Specific receptor → Appropriate spinal nerve (s) → Appropriate plexus (if needed) → Enters appropriate ramus → Dorsal Root Ganglion → Dorsal Root → Dorsal Horn (Synapse) → Thalamus (Synapse) → Internal Capsule → Appropriate Sensory Cortex (Cerebrum)
3. Sensory and Motor Tracings:
- Review the sensory and motor tracings presented and complete the following tracings.
Remember that specific receptors (chemoreceptors, proprioceptors, nociceptors, thermometers, photoreceptors, mechanoreceptors.), effectors, nerves, plexuses, or rami will vary depending on the specific example studied.
a) You step barefoot on hot sand. Trace the sensory message of pain from the receptor on the bottom of your foot to the appropriate sensory cortex. Include the specific nerves. (3pts)
b) Your friend is massaging your back with deep pressure. Trace the sensory message of pressure from the receptor on your back to the appropriate sensory cortex. (3pts)
c) While hanging a picture on the wall the hammer slips and you hit your thumb. You experience a great deal of pain.
- Using the general sensation tract, trace the sensory pathway from the appropriate receptor to the brain. Include the specific nerves. (3pts)
- Now trace the motor pathway from the brain to the wrist extensors to move your thumb away from the hammer. (3pts)
d) In order to perform bicep curls you must flex the anterior flexor muscles of your arm. Trace the motor pathway from the brain to the appropriate muscles. (3pts)
Submission
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