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Flashcards in Neuro Deck (29)
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1

Gastrulation

  • Early phase of embryologic developement
    • occurs during 3rd week of gestation
    • implanted blastula into 3 germ layers
      • Ectoderm
      • Mesoderm
      • Endoderm
  • Reorganization of the bilaminar disc to trilaminar disc
  • Primitive node & streak establish the body axis

2

Ectoderms gives rise to:

  • Integumentary (skin) System
  • Brain
  • Spinal Cord
  • Pituitary Gland

3

Mesoderm gives rise to:

  • Musculoskeletal system
  • Cardiovascular system
  • Excretory system
  • Reproductive system

4

Endoderm gives rise to:

  • Epithelial lining of lungs
  • Digestive system
    • liver
    • pancreas
    • bladder
  • Forms Thyroid and parathyroid glands

5

Neurulation

  • neural tube formation
    • neural plate formation
      • neuroectoderm
    • closure of neural tube
    • early development of the nervous system

6

Formation of the Notochord

 

  • Notochord process
    • extends from the primitive node up to the prochordal plate
    • develops into the notochord
    • around the vertebral column
    • its the nucleus pulposus of the intervertebral discs in adults

 

7

Notochord

Notochord:

  • flxible
  • rod-shaped body
  • derived from mesoderm
  • basis for axial skeleton

 

8

Neurulation: steps

3-4 weeks of gestation

  • Notochordal process--> Notochord
  • Notochord produces Growth Factor
    • Day 17-18
    • Induction of neuroectoderm 
      • ectoderm proliferates/thickens
      • ectoderm differentiates to neuroectoderm of neural plate
  • Neural plate folds on lateral edges to form neural groove (Day 20-21)
    • folds come together in the cervical region
  • Neural Folds fuse along posterior midline 
    • fueled by folate (3-5 mg/day)
    • closure of neuropore proceeds rostral and caudal direction
      • Rostral/Head=Brain
        • Day 24-25
      • Caudal/Tail=Spinal cord 
        • Day 26-27
  • Neural Crest gives rise to PNS
  • Neural tube becomes CNS (Brain & Spinal cord)

 

Week 4-8=Secondary Gestation

9

Folic Acid Supplements

  • reduces the risk of birth defects

10

The Alpha-Fetoprotein (AFP) test

 

  • Measures the levels of alpah-fetoprotein in the pregnant mother's serum or amniotic fluid
  • AFP is apart of CSF
  • AFP presence in maternal serum
    • improper closure of neural tube (neurospores)
    • Anterior portion=Anencephaly (Day 24-25)
    • Posterior portion=Spina Bifida (Day 26-27)

11

Anencephaly

  • Failure of the anterior neuropore to close

12

Spina Bifida

Failure of the vertebral arches to form completely and fuse to cover the spinal cord

  • Failure of the posterior neuropore to close

13

Vesiculation:

Neural Tube--> 3 Primary Brain Vesicles--> 5 Secondary Brain Vesicles

  • Neurospore closure to form neural tube (day 22)
  • Neural tube dilates forming Primary Brain vesicles (24)
    • Prosencephalon (Forebrain)
    • Mesencephalon (Midbrain)
    • Rhombocephalon (Hindbrain)
  • 5 secondary Brain vesicles:
    • Prosencephalon (Forebrain)
      • Telencephalon
      • Diencephalon
    • Mesencephalon (midbrain)
    • Rhombencephalon (Hindbrain)
      • Metencephalon
      • Myelencephalon

14

Telencephlaon develops into:

  • Cerebrum/Cerebral hemispheres (neocortex)
    • cerebral cortex
    • Basal Ganglia
      • Corpus striatum
    • White Matter
    • olfactory cortex (paleocortex)
  • Lateral Ventricles
  • Olfactor Nerve (CN1)

15

Diencephalon develops into: 

  • Thalamus
  • Hypothalamus
  • Epithalamus
    • pineal gland
  • Subthalamus
  • Mammalary bodies 
  • Optic Cup
  • Optic Nerve (CN2)
  • Neurohypophysis 
    • posterior lobe of pituitary gland
  • 3rd Ventricle

16

Mesencephalon Develops into

  • Midbrain
    • Tectum 
      • Superior/inferior colliculi)
    • Red Nucleus
    • Substantia Nigra
    • Crus cerebelli 
  • Cerebral Aqueduct
  • CN:
    • 3=Occulomotor
    • 4=Trochlear

17

Metencephalon develops into:

  • Pons
  • Cerebellum
  • 4th Ventricle 
  • CN:
    • 5= Trigeminal
    • 6=Abducens
    • 7=Facial

18

Myelencephalon develops into:

  • Medulla Oblongata 
  • 4th Ventricle
  • CN:
    • 8= vestibulocochlear
    • 9=Glossopharyngeal
    • 10=Vagus
    • 11=Acessory
    • 12=Hypoglossal

19

Neural Crest Cells:

  • Ectodermal
  • Found along the length of the neural tube
  • Migrate when the neural tube is formed
  • Any neuron with a cell body outside the CNS is of neural crest origin
  • Differentiate into:
    • Sensory ganglia of CV 5,7,9, 10
    • DRG of PNS
    • Schwann cells of PNS
    • Adrenal Medulla
    • Melanocytes and odontoblasts
    • Head skeleton
    • Peripheral glial cells
    • Peripheral afferent neurons
    • Neurons in Autonomic ganglia 
      • including adrenal medulla
    • Leptomeninges develop into Brain
      • pia and arachnoid mater
    • Chromaffin cells
      • in adrenal gland
    • Enterochromaffin cells
      • in GI tract

20

CNS Developement: Spinal Cord

Develops from Caudal end of neural tube

  • After caudal neurospore close, sulcus limitans forms
  • Sulcus limitans seperates:
    • Alar plate (dorsal)
      • comes from mantle layer
      • sensory
      • Develop into dorsal horn
    • Basal Plate (ventral)
      • Motor
      • develop into Ventral horn
  • Neuroepithelial cells:
    • neuroblast cells
    • capable of dividing
  • Mantle Layer
    • Grey matter
  • Marginal Layer
    • White matter

21

Brain: Rostral vs Caudal

Rostral: Toward the forehead

 

Caudal: Toward the spinal cord

22

Brain: Fun facts

  • Brain weighs:
    • 1,600g=Men
    • 1,450g=Women
  • Adult brain composed of:
    • 100 billion neurons

 

23

CNS contains:

  • Brain
  • Spinal Cord
  • Neurons
  • Neuroglia (protect and support neurons)
    • Astrocytes
      • Maintain BBB
    • Oligodendrocytes 
      • Schwann Cells
      • Myelination
    • Microglia
      • Phagocytotic
    • Ependymal cells
      • Help produce CSF
      • more found:
        • around ventricles
        • in central canal of spinal cord

24

Cerebral Hemisphere:

  • 83% of total brain mass
  • Covers the diencephalon and upper brain stem 
  • Gyri=bumps
  • Sulcus=grooves

25

Central Sulcus

  • AKA: Fissure of rolando
  • Seperates frontalxt and parietal lobe

26

Lateral Fissure

  • AKA sylvian fissure
  • seperates frontal from temporal lobe

27

Tentorium Cerebeli 

  • Dura Mater
  • seperates the cerebellum from bottom part of brain

28

Longitudinal Fissure

  • aka Interhemispheric fissue
  • seperates the 2 cerebral hemispheres

29