spinal tracts, germ layer derivatives

Question 1

DCML
start -
end -
decussates -
role/information conveyed -

Answer 1

start - proprioceptive fibres of legs (fasciculus grascilis) and arms (fasciculus cuneatus)
end - parietal lobe: somatosensory cortex
decussates - medulla
role - 2 point discrimination, fine touch, vibration

Question 2

Spinothalamic
start -
end -
decussates -
role/information conveyed -

Answer 2

start - nociceptors and thermoreceptors, mechanoreceptors
end - thalamus, then on to somatosensory cortex in parietal lobe
decussates - level it enters the spinal cord, or 1/2 levels above
role - pain and temp (lateral), crude touch (anterior)

Question 3

Spinocerebellar
start -
end -
decussates -
role/information conveyed -

Answer 3

start - proprioceptive fibres
end - cerebellum
decussates - dorsal don’t decussate, ventral double cross - so information ends up being ipsilateral for both
role/information conveyed - balance, coordination, proprioception

Question 4

Lateral corticospinal
start -
end -
decussates -
role/information conveyed -

Answer 4

start - motor cortex
end - motor end plate/NMJ
decussates - medulla
role/information conveyed - motor to limbs

Question 5

Anterior corticospinal
start -
end -
decussates -
role/information conveyed -

Answer 5

start - motor cortex
end - motor end plate/NMJ
decussates - dont decussate
role/information conveyed - motor to trunk

Question 6

Rubrospinal
start -
end -
decussates -
role/information conveyed -

Answer 6

start - red nucleus (midbrain)
end - motor end plate/NMJ
decussates - midbrain
role/information conveyed - rudimentary motor functions

Question 7

Tectospinal
start -
end -
decussates -
role/information conveyed -

Answer 7

start - tectum (midbrain)
end - motor end plate/NMJ
decussates - midbrain
role/information conveyed - reflex, involved in turning towards loud noise

Question 8

Descending tracts

Answer 8

vestibulospinal, reticulospinal, tectospinal, corticospinal (anterior and lateral), rubrospinal

Question 9

ascending tracts

Answer 9

DCML
spinothalamic
spinocerebellar

Question 10

what does ectoderm develop to form

Answer 10

Glands: Subcutaneous glands, mammary glands, pituitary glands
Epidermis (skin, hair, nails)
Nervous system: CNS, PNS
Tooth enamel
Ears (sensory epithelium)
Eyes (sensory epithelium)
Nose (sensory epithelium)

Question 11

3 parts of the mesoderm

Answer 11

1. paraxial mesoderm (closest to notochord)
2. intermediate mesoderm
3. lateral mesoderm = parietal and visceral

Question 12

what does paraxial mesoderm develop to form

Answer 12

Somites (each somite is area supplied by 1 spinal nerve)

• myotome (muscle tissue)
• sclerotome (cartilage and bone)
• dermatome (dermis of skin)

Question 13

what does intermediate mesoderm develop to form

Answer 13

the urogenital system:

• kidneys, gonads, respective ducts
• male and female genitalia

Question 14

what does lateral mesoderm develop to form

Answer 14

a) parietal - inside of chest and abdominal wall covering

b) visceral - organs in thorax and abdomen

Question 15

what does endoderm develop to form

Answer 15

• epithelial lining of the GI tract, RS tract and urinary bladder
• parenchyma of the thyroid, parathyroid, liver and pancreas
• epithelial lining of the auditory tube and tympanic cavity