Weel 8 handout answers Flashcards
From where in the spinal cord do cell bodies of sympathetic neurons arise?
lateral horn
Sympathetic neurons arise from which spinal segments?
T1-L2
What are the two branches of the mixed spinal nerve and what do they innervate?
- dorsal ramus 2. ventral ramus
What are the two divisions of the sympathetic rami communicantes?
- white rami = preganglionic 2. gray rami = postganglionic
Which sympathetic rami communicantes are myelinated?
white rami
Which sympathetic rami communicantes are unmyelinated?
grey rami
Which sympathetic rami communicantes enter the sympathetic paravertebral ganglion?
white rami
Which sympathetic rami communicantes leaves the sympathetic paravertebral ganglion to rejoin the spinal nerve?
grey rami
Why are there 8 cervical spinal nerves when there are only seven cervical vertebrae?
C7exits above C7, T1 exits below T1, therefore C8 exits below C7
The ventral rami of T1-T12 spinal nerves are known as?
intercostal nerves
The most important nerve of the cervical plexus is?
phrenic nerve
What are the five major branches of the brachial plexus?
- axillary 2. radial 3. ulnar 4. median 5. musculocutaneous
Name the 2 major nerves of the lumbar plexus?
- femoral 2. obturator
What is the major nerve of the sacral plexus?
sciatic nerve
2 components of sciatic nerve
tibial and peroneal
Which spinal nerve doesn’t participate in dermatomes?
C1
- What are the three levels of motor control?
- segmental 2. projection 3. pre-command
What are the five components of any reflex arc?
- receptor 2. afferent neuron 3. integration center (CNS) 4. efferent neuron 5. effector
What is the muscle spindle and what is its role in the stretch reflex?
muscle stretch receptor prevents overstretching by activating stretched muscle and inhibiting antagonist
- What is the Golgi tendon organ and what is its role in the Golgi tendon reflex?
muscle contraction receptors prevent overcontraction by inhibiting contracting muscle and activating antagonist
- What happens during the flexor reflex?
automatic withdrawal (flexion) of the body part (limb)
- What happens during the crossed extensor reflex?
- stimulated side is withdrawn (flexion) and 2. contralateral side extended
- What is the difference between the plantar reflex and the Babinski sign?
Babinski = hallux extension ONLY; other plantar reflexes: 1. flexor 2. equivocal
