Spinal Anatomy (Joe)

Question 1

Mesoderm Subgroups (4)

Answer 1

Paraxial (somatic and splanchnic)

Intermediate

Head

Lateral Plate

Question 2

Endoderm derivatives

Answer 2

Organs, gut, respiratory tract

“tubular structures”

Question 3

Mesoderm: Paraxial

(two parts…)

Answer 3

Somatic:
musculoskeletal- muscles, ligaments, tendons…

Splanchnic
smooth muscle of organs

Question 4

Mesoderm: Intermediate

Answer 4

Urogenital system and kidneys

Question 5

Mesoderm: Head

Answer 5

skull muscles, dentine of teeth

Question 6

Mesoderm: Lateral Plate

Answer 6

Adrenal cortex, connective tissue, cardiovascular and lymph

Question 7

Ectoderm Subgroups

Answer 7

“Ectoderm: nerves and skin”

Surface ectoderm

Neuroectoderm (2)

Question 8

Ectoderm: Surface Ectoderm

Answer 8

Epidermis, anterior pituitary, lens of eye, skin, enamel, hair, nails

Question 9

Ectoderm: Neuroectoderm

(Subgroups and derivatives)

Answer 9

Neural Tube
posterior pituitary, retina of eye, CNS, oligodendrocyte
CNS: brain and sc

• *Neural Crest**
• *Outside CNS:** sympathetic chain gangion, DRG, ANS, PNS, Schwann cells, Parafollicular cells of thyroid, adrenal medulla

Question 10

Neuroectoderm:

Embryological order

Answer 10

notochord
↓
neural plate
​↓
neural groove
​↓
neural tube
​↓
neural crest cell

Question 11

CNS Pathologies derived from neural tube defects:

Spina Bifida Occulta

Answer 11

lamina failed to fuse

tuft of hair growth = “fawn’s beard”

Caused by folic acid deficiency

(“Folic acid” / “Vit B9” / “methylfolate” / “tetrahydrofolate”)

Question 12

CNS Pathologies derived from neural tube defects:

Spina Bifida Vera / “Spina Bifida Manifesta”

Meningocele, myelocele, meningiomyelocele…

Answer 12

Meningocele: meninges protrude

Myelocele: sc protrudes because of underdeveloped meninges

Meningiomyelocele: sc and meninges protruding

Question 13

CNS Pathologies derived from neural tube:

Arnold Chiari Syndrome
(two types)

Answer 13

Type I:
cerebellar peduncles come below foramen magnum

Type II:
Type I + meningiomyelocele

Question 14

CNS Pathologies derived from neural tube:

Cleft Palate

Answer 14

failure of maxillary and palatine bones to fuse

neural tube defect, B9 deficiency

Question 15

(Embryological stages of development)

Mesodermal Development

Answer 15

Sclerotome = membranous vertebral column

Myotome = muscle

• Somatic: skeletal muscle
• Splanchnic: “visceral” smooth muscle
• Epimere: dorsal, posterior mm, extensors
• Hypomere: ventral, anterior mm, flexors

Dermatome = nerves

Question 16

(Embryological stages of development)

Ossification

Answer 16

intramembranous/intramedullary ossification

• mesenchymal tissue → bone
• clavicle / parietal bone*

*or any skull bone, all are partially intramembranous

Enchondral ossification = preformed in cartilage

• ossification for all other bones (98%)

Question 17

Dorsal Primary Rami

Answer 17

to back mm

Question 18

Ventral Primary Rami

Answer 18

to front mms

Exception: any back mm that is innervated by a nerve coming off brachial plexus is primary..

rhomboids → dorsal scapular n

latissimus dorsi → thoracodorsal n

Question 19

(GI Embryology)

Mouth

Foregut

Midgut

Hindgut

Answer 19

Mouth: stomodeum

Foregut: back of throat to first ¹/₃ duodenum

Midgut: last ^{<span>2</span>}/₃ duodenum to first ^{<span>2</span>}/₃ transverse colon

Hindgut: last ^{<span>1</span>}/₃ transverse colon to anus

Question 20

The Gubernaculum

Answer 20

Males
becomes scrotal ligament aka “gubenacular testes”

Females
suspensory ligament of ovary, ovarian lig, and round lig.

Question 21

Primary and Secondary Vesicles

Answer 21

“Tell Di Mes Met Mye”

Prosencephalon

• Telencephalon
• Diencephalon

Mesencephalon

• Mesencephalon

Rhombencephalon

• Metencephalon
• Myelencephalon

Question 22

Telencephalon

Answer 22

Derived from Prosencephalon

Cortices, basal ganglion, cingular gyrus

CN I (Olfactory n)

Lateral Ventricle

Question 23

Diencephalon

Answer 23

Derived from Prosencephalon

thalamus (hypo-, epi-, sub-)
*epithalamus = pineal gland

CN II (Optic n)

3rd ventricle

Question 24

Mesencephalon

Answer 24

remains mesencephalon

midbrain

CN III (oculomotor)
CN IV (trochlear) 
*\*only CN off posterior portion of brainstem, and contralateral*

Aqueduct of Sylvius AKA Cerebral Aqueduct

Question 25

Metencephalon

Answer 25

From Rhombencephalon

Pons and cerebellum

CNs 5-8
(V: trigeminal, VI: abducens, VII: facial, VIII: vestibulocochlear)

roof of 4th ventricle

Question 26

Myelencephalon

Answer 26

From Rhombencephalon

medulla oblongata

CNs 9-12
(IX: glossopharyngeal, X: vagus, XI: accessory, XII: hypoglossal)

floor of 4th ventricle

*fold of tissue at floor of 4th vent: “obex”
just below 4th ventricle: cisterna magna/”cerebellomedullary cisterm”

Question 27

(Neurology)

Dendrites vs Axons

Answer 27

Dendrites: impulse towards cell body

Axon: impulse away from body

*impulse originates at axon hillock

Question 28

Overview

Answer 28

receptor (dendrite) → peripheral nerve → spinal cord → brainstem → cerebellum

(or) ↓

thalamus → parietal lobe → Wernicke’s area (POT) → limbic system → motor response

*Only senseation that bypasses thalamus is smell. Cerebellum receives information after impulses pass thru brainstem and also from cortex

Question 29

(Action Potential)

Resting Membrane Potential
muscle vs neuron

Answer 29

Resting Membrane Potential: (-) inside, (+) outside

large molecules create (-) inside, sodium creates (+) outside

Muscle = (-85-90mv)

Neuron = (-65-70mv)

Question 30

(Action Potential)

Receptors

Answer 30

Allow Na+ leak into cell, twoards depolarization of nerve for AP

Depolarization = Na+ rushing in