Chapter 13 - Spinal Cord Flashcards
What are the functions of the spinal cord?
- Conduction
- Locomotion
- Reflexes
What are the two spinal enlargements?
- Cervical enlargement - gives rise to nerve in upper arm
2. Lumbar enlargement - gives rise to nerves in legs
Bundle of spinal nerves
Cauda Equina
Extension of the pia mater that prevents superior motion
Terminal filum
Extension of the pia mater that prevents lateral motion
Denticulate ligaments
List the steps in a Reflex Arc (5)
- Sensory receptor
- Sensory neuron
- Interneuron
- Motor neuron
- Effector organ
What are the three connective tissues covering the brain and spinal cord?
- Dura mater - outer layer
- Arachnoid mater - middle layer
- -*Contains CSF! - Pia mater - delicate inner layer
What are the nerves of the Cervical plexus?
(C3-C5)
-Phrenic nerve - diaphragm; regulates breathing!
What are the nerves of the Brachial plexus?
(C5-C8 + T1)
- Musculocutaneous - biceps
- Axillary - deltoid + teres minor
- Radial - forearm extensors
- Median - forearm flexors
- Ulnar - wrist flexion and adduction
What are the nerves of the Lumbar plexus?
(L2-L4)
- Obturator - thigh muscles
- Femoral - inner thigh + quadriceps
What are the nerves of the Sacral plexus?
(L4-L5 + S1-S3)
- Sciatic - splits into tibial + fibular nerves
a. Tibial - hamstring (semitendinosus + semimembranosus)
b. Fibular - anterior / lateral lower leg (biceps femoris)
How is the withdrawal reflex related to the cross-extension reflex? What is an example of this?
Sensory stimuli from withdrawal reflex cross from the stimulated side of the body to the contralateral side –> synapses w/ interneurons to flex extensor muscles
Ex: Stepping on a nail
- -Withdrawal: leg that stepped on nail
- -Extend: leg that the weight is shifted onto
Area of skin that a single spinal nerve root innervates
Dermatomes
Group of muscles that a single spinal nerve root innervates
Myotomes
