Spinal Anatomy (Joe) Flashcards
Spinal Anatomy (Joe)
Mesoderm Subgroups (4)
Paraxial (somatic and splanchnic)
Intermediate
Head
Lateral Plate
Endoderm derivatives
Organs, gut, respiratory tract
“tubular structures”
Mesoderm: Paraxial
(two parts…)
Somatic:
musculoskeletal- muscles, ligaments, tendons…
Splanchnic
smooth muscle of organs
Mesoderm: Intermediate
Urogenital system and kidneys
Mesoderm: Head
skull muscles, dentine of teeth
Mesoderm: Lateral Plate
Adrenal cortex, connective tissue, cardiovascular and lymph
Ectoderm Subgroups
“Ectoderm: nerves and skin”
Surface ectoderm
Neuroectoderm (2)
Ectoderm: Surface Ectoderm
Epidermis, anterior pituitary, lens of eye, skin, enamel, hair, nails
Ectoderm: Neuroectoderm
(Subgroups and derivatives)
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
Neuroectoderm:
Embryological order
notochord
↓
neural plate
↓
neural groove
↓
neural tube
↓
neural crest cell
CNS Pathologies derived from neural tube defects:
Spina Bifida Occulta
lamina failed to fuse
tuft of hair growth = “fawn’s beard”
Caused by folic acid deficiency
(“Folic acid” / “Vit B9” / “methylfolate” / “tetrahydrofolate”)
CNS Pathologies derived from neural tube defects:
Spina Bifida Vera / “Spina Bifida Manifesta”
Meningocele, myelocele, meningiomyelocele…
Meningocele: meninges protrude
Myelocele: sc protrudes because of underdeveloped meninges
Meningiomyelocele: sc and meninges protruding
CNS Pathologies derived from neural tube:
Arnold Chiari Syndrome
(two types)
Type I:
cerebellar peduncles come below foramen magnum
Type II:
Type I + meningiomyelocele
CNS Pathologies derived from neural tube:
Cleft Palate
failure of maxillary and palatine bones to fuse
neural tube defect, B9 deficiency
(Embryological stages of development)
Mesodermal Development
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
(Embryological stages of development)
Ossification
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%)
Dorsal Primary Rami
to back mm
Ventral Primary Rami
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
(GI Embryology)
Mouth
Foregut
Midgut
Hindgut
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
The Gubernaculum
Males
becomes scrotal ligament aka “gubenacular testes”
Females
suspensory ligament of ovary, ovarian lig, and round lig.
Primary and Secondary Vesicles
“Tell Di Mes Met Mye”
Prosencephalon
- Telencephalon
- Diencephalon
Mesencephalon
- Mesencephalon
Rhombencephalon
- Metencephalon
- Myelencephalon
Telencephalon
Derived from Prosencephalon
Cortices, basal ganglion, cingular gyrus
CN I (Olfactory n)
Lateral Ventricle
Diencephalon
Derived from Prosencephalon
thalamus (hypo-, epi-, sub-)
*epithalamus = pineal gland
CN II (Optic n)
3rd ventricle
Mesencephalon
remains mesencephalon
midbrain
CN III (oculomotor) CN IV (trochlear) *\*only CN off posterior portion of brainstem, and contralateral*
Aqueduct of Sylvius AKA Cerebral Aqueduct
Metencephalon
From Rhombencephalon
Pons and cerebellum
CNs 5-8
(V: trigeminal, VI: abducens, VII: facial, VIII: vestibulocochlear)
roof of 4th ventricle
Myelencephalon
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”
(Neurology)
Dendrites vs Axons
Dendrites: impulse towards cell body
Axon: impulse away from body
*impulse originates at axon hillock
Overview
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
(Action Potential)
Resting Membrane Potential
muscle vs neuron
Resting Membrane Potential: (-) inside, (+) outside
large molecules create (-) inside, sodium creates (+) outside
Muscle = (-85-90mv)
Neuron = (-65-70mv)
(Action Potential)
Receptors
Allow Na+ leak into cell, twoards depolarization of nerve for AP
Depolarization = Na+ rushing in
