Neuro Flashcards
(29 cards)
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
Ectoderms gives rise to:
- Integumentary (skin) System
- Brain
- Spinal Cord
- Pituitary Gland
Mesoderm gives rise to:
- Musculoskeletal system
- Cardiovascular system
- Excretory system
- Reproductive system
Endoderm gives rise to:
- Epithelial lining of lungs
- Digestive system
- liver
- pancreas
- bladder
- Forms Thyroid and parathyroid glands
Neurulation
- neural tube formation
- neural plate formation
- neuroectoderm
- closure of neural tube
- early development of the nervous system
- neural plate formation
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
Notochord
Notochord:
- flxible
- rod-shaped body
- derived from mesoderm
- basis for axial skeleton
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
- Rostral/Head=Brain
- Neural Crest gives rise to PNS
- Neural tube becomes CNS (Brain & Spinal cord)
Week 4-8=Secondary Gestation
Folic Acid Supplements
- reduces the risk of birth defects
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)
Anencephaly
- Failure of the anterior neuropore to close
Spina Bifida
Failure of the vertebral arches to form completely and fuse to cover the spinal cord
- Failure of the posterior neuropore to close
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
- Prosencephalon (Forebrain)
Telencephlaon develops into:
- Cerebrum/Cerebral hemispheres (neocortex)
- cerebral cortex
- Basal Ganglia
- Corpus striatum
- White Matter
- olfactory cortex (paleocortex)
- Lateral Ventricles
- Olfactor Nerve (CN1)
Diencephalon develops into:
- Thalamus
- Hypothalamus
- Epithalamus
- pineal gland
- Subthalamus
- Mammalary bodies
- Optic Cup
- Optic Nerve (CN2)
- Neurohypophysis
- posterior lobe of pituitary gland
- 3rd Ventricle
Mesencephalon Develops into
- Midbrain
- Tectum
- Superior/inferior colliculi)
- Red Nucleus
- Substantia Nigra
- Crus cerebelli
- Tectum
- Cerebral Aqueduct
- CN:
- 3=Occulomotor
- 4=Trochlear
Metencephalon develops into:
- Pons
- Cerebellum
- 4th Ventricle
- CN:
- 5= Trigeminal
- 6=Abducens
- 7=Facial
Myelencephalon develops into:
- Medulla Oblongata
- 4th Ventricle
- CN:
- 8= vestibulocochlear
- 9=Glossopharyngeal
- 10=Vagus
- 11=Acessory
- 12=Hypoglossal
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
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
- Alar plate (dorsal)
- Neuroepithelial cells:
- neuroblast cells
- capable of dividing
- Mantle Layer
- Grey matter
- Marginal Layer
- White matter
Brain: Rostral vs Caudal
Rostral: Toward the forehead
Caudal: Toward the spinal cord
Brain: Fun facts
- Brain weighs:
- 1,600g=Men
- 1,450g=Women
- Adult brain composed of:
- 100 billion neurons
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
- Astrocytes
Cerebral Hemisphere:
- 83% of total brain mass
- Covers the diencephalon and upper brain stem
- Gyri=bumps
- Sulcus=grooves