MT1

Question 1

Describe the key developments during neurlation and what each component becomes.

Answer 1

1. The notochord induces the ectoderm to curve and form the neural plate -> neural tube
2. The formation of the neural tube goes into the mesoderm layer and the “floating” ectoderm cells form the neural crest.

The neural tube = CNS, ventricular system, central canal
Neural crest = Afferent ganglion cell (becomes the spinal root)

Question 2

What does the neural crest become

Answer 2

• spinal ganglia
• Sympathetic ganglia
• Melanocytes

Question 3

What happens during neurulation and mesoderm differentiation?

Answer 3

• cells have specialized functions
• Neural tube is continuous
• Somites are starting to segment
• Creating spaces: the coelom

Question 4

What are two possible problems with an open neural tube during development?

Answer 4

1. Spina bifida - when the neural tube doesn’t close (Imagine a lump on the rump)
2. Encephalocele - When the cranial part of the neural tube doesn’t close (Imagine a lump on the skull)

Question 5

Ways to prevent neural tube defect and how they work?

Answer 5

• Folic acid and B12 supplementation

These supplements help with DNA and RNA synthesis, which is required during rapid proliferation and migration.

Question 6

Name the major different brain regions (vesicles).

Answer 6

Prosencephalon
- Telencephalon
—- Cerebral hemispheres
- Diencephalon
—- Thalamus
—- Hypothalamus
—- Subthalamus

Mesencephalon
—- Midbrain

Rhombencephalon
- Metencephalon
—- Pons
—– Cerebellum
- Myelencephalon
—- Medulla

Question 7

Parts of the spinal cord during development.

Answer 7

Alar plate - Develops into the sensory
Basal plate - develops into the motor
Central canal - Canal that contains CSF which can help transfer nutrients to the spinal cord.
Sulcus limitans - The region that separates the alar and basal plate.

Question 8

Describe how the PNS is formed. (CHECK)

Answer 8

1. The neural crest forms the neural ganglions for sensory neurons and extends through the somites. The neural tube differentiates and has some motor somas that also extends through the somites to the target muscles.

Question 9

What is dermatome and myotome?

Answer 9

The dermatome are slices of the body where sensory neurons from each somites are supplied by stimulus.

The myotome are regions of muscles that are supplied by motor neurons in a single spinal segment.

Question 10

Neurological exam for predominat spinal segment

Answer 10

C2: Neck flexion/extension
C3: Neck lateral flexion
C4: Initiation of shoulder elevation
C5: Shoulder abduction
C6: Elbow flexion/wrist extension
C7: Elbow extension/wrist flexion
C8: Finger flexion
T1: Finger abduction
L1/2: Hip flexion
L3: Knee extension
L4/5: Ankle dorsiflexion
L5: Great toe extension
S1: knee flexion
S2: Ankle plantar flexion/toe flexion
S3/4: Anal wink

Question 11

What does the viseral system do? Where are they located? Where do the information travel through/to?

Answer 11

The viseral system manages all the autonomic functions and sensories in the internal organ. This is because the internal organs use smooth muscles that are not controlled via the somatic sensories. The viseral system is separated into sympathetic and parasympathetic systems. Sympathetic is for fight/flight and parasympathetic is for rest/digest.

The nuclei of the efferent sympathetic is in the lateral horn between T1 - L1/2. The nuclei of the efferent parasympathetic is in the lateral horn within the sacral segment and in the cranial nerves.

Viseral sensory about pain or temperature travel towards the sympathetic segments while the information about physiological function travels toward the parasympathetic segments.