Part of the spinal cord below the conus medullaris,

(end of the spinal cord)

Groups of axons that project inferiorly from the spinal cord like a horses tail

Dermatome

(2)

A specific segment of skin supplied by a single spinal nerve.

All spinal nerves except of C1 innervate a segment of skin

Nerve Plexuses - definition

(4)

1. A network of interweaving spinal nerves
2. Split into multiple "named" nerves that innervate various body structures
3. Web of nerves that exit spinal cord then come together
4. 4 Plexuses

1. Cervical
2. Brachial
3. Lumbar
4. Sacral

1. Innervate Anterior nect and parts of the head and shoulders
2. Phrenic Nerve -innervates the diaphragm
3. C3, C4, C5 come together to make Phrenic Nerve

1. Innervate pectoral girdle and upper limbs
2. Begins above the shoulders
3. 5 nerves to know

Musculocutaneous nerve

Median Nerve

Axillary nerve

Ulnar nerve

Radial nerve

Lumbar Plexus

(2)

1. Innervation of lower limb
2. Femoral nerve - innervated anterior muscles of thigh

1. Innervation of lower limb
2. Sciatic nerve

Longest and largest nerve in the body

Supplies all of lower limb except anterior and medial regions of the thigh

Cervical Plexus - Phrenic Nerve

Brachial Plexus - Axillary Nerve

Lumbar Plexus - Femoral Nerve

Sacra Plexus - Sciatic Nerve

Common Fibular Division

Tibial Division

1. Rapid automatic, involuntary reactions of muscles or glands to a stimulus
2. All reflexes have similar properties

1. A stimulus - required to initate a response to sensory input
2. Rapid response requires that few neurons be involved
3. Synaptic delay must be minimal
4. An Automatic response occurs the same way every time

Components of a Reflex Arc

(3 explain - 5 steps)

• Begins with a receptor - PNS
• Communicates with CNS
• Ends - peripheral effector cell - muscle or gland

1. Receptor
2. Sensory afferent neuron
3. association neuron
4. motor efferent neuron
5. effector

Two types of Reflexes

1. Monosynaptic
2. Polysynaptic

• Simplies of all reflexes
• No interneurons
• senory afferent neuron is synapsed with the motor efferent neuron
• eg. patellar knee-jerk

• More complex neuro pathways
• A number of synapses w/ interneurons w/i the reflex arc
• More components= longer delay b/t stimulus and response
• e.g. Pain reflex

Forms Cranial and Spinal nerves

Split off from the developing neiral tube

Where are the White and Gray matter located on the Spinal Cord?

Where are the White and Gray matter located in the brain?

Twinkie and Hot Dog

1. White matter out side - Gray matter inside, Spinal cord is like a  Hot Dog
2. Gray matter out side - White matter inside, the brain is like a twinkie.