CBCfirstlecture

Question 1

Types of neurons

Answer 1

MOTOR neurons = MULTIPOLAR (several dentrite processes and a single axon attached to cell body)

Bipolar neuron = single dendrite and single axon (olfactory nerves and retina). Not talking much about today.

Unipolar neurons = do not exist in our nervous system

SENSORY neurons = PSEUDOUNIPOLAR neuron = one process from cell body that diverges to two sides. One part has receptor on one end/the receiving end (dendrite=peripheral process), and other process is axon (=central process) to carry information away from cell.

Question 2

Definitions: 
Nucleus
Ganglion
Tract
Nerve
Gray Matter
White Matter

Answer 2

Nucleus = collection of nerve cell bodies in CNS
Ganglion= collection of nerve cell bodies in PNS
Tract = collection of nerve processes (axons) in CNS
Nerve = collection of nerve processes (axons) in PNS
Gray matter = unmyelinated (mostly cell bodies and dendrites)
White matter = myelinated (mostly axons)

Question 3

Spinal cord - Function

Know that the Brain and Spinal cord are Anatomically Continuous!

Answer 3

Primary function of the spinal cord is to connect the brain with the periphery (rest of the body). So if there is no spinal cord, you cannot get information to and from the brain!

1) Afferents = SENSORY information that comes into/towards the brain (spinal cord receives afferent info and carries it toward brain) = Pseudounipolar
2) Efferent = MOTOR information that comes from the brain and is carried to the body = Multipolar with body in the spinal cord containing dendrites to receive info from brain (so it is a nucleus).
3) Spinal reflexes = the third/final function of the spinal cord that we won’t discuss much today. This doesn’t send information to/from the brain, but just spinal cord and body.
* double check with professor if always nucleus for motor and always ganglion for sensory.

Question 4

Protection of Spinal cord (3 layers)

Answer 4

1) Bone (outermost layer)
2) Three Connective Tissue Layers = Mininges (Dura=outer, Arachnoid=middle, Pia=inner)
3) CSF = cererbrospinal fluid =innermost around spinal cord

Question 5

What to know about vertebrae

Answer 5

VERTEBRAL FORAMEN is opening of spine/vertebrae between body and neural arch. Several vertebrae line together so the foremen becomes VERTEBRAL CANAL which holds spinal cord.

INTERVERTEBRAL FORAMEN = formed by two vertebrae on each lateral side for nerves/axons going to periphery to exit the spinal cord. (only exception is first cervical spinal nerve, C1, doesn’t require intervertebral foramen since it’s above the first cervical vertebrae)

Question 6

Spinal nerves (31 pairs)

Answer 6

31 pairs of spinal nerves!

8 Cervical Pairs C1-C8 (each one is above the same number cervical vertebra because C1 doesn’t require intervertabral foramen/above first C1 vertebrae, and so this makes the final pair C8 which is below the C7 vertebra)

All the rest are always below the same numbered vertebrae

12 Thoracic Pairs (T1-T12)
5 Lumbar Pairs (L1-L5)
5 Sacral Pairs (S1-S5)
1 Coccygeal Pair (Co1) since the coccyx is fused. (maybe this is in the middle of coccyx, can check with professor)

Cervical, Thoracic, Lumbar, Sacral, Coccygeal = 8, 12, 5, 5, 1 = 31 pairs total

Question 7

Meninges (3 connective tissue layers)

Outermost later/Dura Mater and Filum Terminale(external)

Answer 7

1) Dura Mater (outer ct layer) = layer of DENSE connective tissue. Means tough mother. It forms sleeve/dural sac around the spinal cord. It continues superiorly around the brain. It ends inferiorly at S2 (the second sacral level inside the sacrum).

After this there is a cord-like ligament called the “filum terminale(external)” that connects the S2/anchors the inferior end of sleeve/dural sac to the coccyx.

Question 8

Meninges (3 Connective Tissue layers)

Middle layer/Arachnoid Mater

Answer 8

Arachnoid Mater = between the dura and the pia mater. This one means “spider like”. It is a THIN TRANSPARENT layer that has web-like extensions to the pia mater.

Question 9

Meninges (3 Connective Tissue layers)

Innermost layer/Pia Mater and Filum Terminale(internal) and Denticulate Ligaments/lateral extensions

Answer 9

Means “delicate mother”. It is a VERY THIN layer of Connective tissue. It INVESTS spinal cord (it is right connected to the spinal cord).

It forms Filum Terminale(internal). This is inferiorly-continuation of pia off of inferior spinal cord anchored to base of dural sac.

The pia mater also has LATERAL EXTENSIONS = “DENTICULATE LIGAMENTS” that attach to dura laterally and anchor the spinal cord.