Nervous System Embryology (REYNOLDS) Flashcards
Which of the following innervates the skin and most skeletal muscles?
A. Somatic nervous system
B. Visceral nervous system
A. Somatic nervous system
Visceral (autonomic) nervous system:
- innervates the viscera and smooth mucles and glands
- sympathetic and parasympathetic divisions
- both divisions consist of preganglionic and postganglionic fibers
Which of the following is associated in the formation of the neural tube?
A. Thickening of neural plate
B. Elongation of neural plate
C. Lateral folding
D. Fusion of opposing neural folds and separation from overlying ectoderm
E. All of the above
E. All of the above
In the formation of the neural tube, Lateral folding includes all of the following EXCEPT:
A. Neural crest cells
B. Neural groove
C. Median hinge point
D. Lateral hinge points
E. All of the above
A. Neural crest cells
Fusion of opposing neural folds and separation from overlying ectoderm = neural crest cells
Which of the following is involved in the fusion of opposing neural folds and separation from overlying ectoderm?
A. Median hinge point
B. Neural groove
C. Neural crest cells
D. Lateral hinge points
E. All of the above
C. Neural crest cells
Molecular signals for brain development are initiated at the neural plate. BMPs establish motor regions and SHH establishes sensory regions.
A. First statement is true, second is false
B. First statement is false, second is true
C. Both statements are true
D. Both statements are false
A. First statement is true, second is false
Correct statement: Molecular signals for brain development are initiated at the neural plate. BMPs establish sensory regions and SHH establishes motor regions.
BMPs = sensory region
SHH = motor region
At what week does the brain split into the three segments: Prosencephalon, Mesencephalon and Rhombencephalon?
A. Week 1
B. Week 2
C. Week 3
D. Week 4
E. Week 5
D. Week 4
Week 4 = 3 brain segments (prosencephalon, mesencephalon, rhombencephalon)
Week 5 = 5 brain segments (Telencephalon, Diencephalon, Mesencephalon, Metencecphalon, Myelencephalon
All of the following are brain segments that arise at week 4 EXCEPT:
A. Prosencephalon
B. Metencephalon
C. Mesencephalon
D. Rhombencephalon
B. Metencephalon
Week 4 = Procephalon, Mesencephalon, Rhombencephalon
Week 5 = Telencephalon, Diencephalon, Mesencephalon, Metencephalon, Myelencephalon
List the 5 brain segments at week 5 in order from cranial to caudal:
- Telencephalon
- Diencephalon
- Mesencephalon
- Metencephalon
- Myelencephalon
What are the 3 brain segments that arise in the 4th week?
- Prosencephalon
- Mesencephalon
- Rhombencephalon
What are the 5 brain segments that arise in the 5th week in order from cranial to caudal?
- Telencephalon
- Diencephalon
- Mesencephalon
- Metencephalon
- Myelencephalon
The Prosencephalon divides into all of the following EXCEPT:
A. Telencephalon
B. Metencephalon
C. Diencephalon
D. Prosencephalon divides into all of the above
B. Metencephalon
Prosencephalon = Telecephalon and Diencephalon
Rhombencephalon = Metencephalon and Myelencephalon
The Rhombencephalon divides into all of the following EXCEPT:
A. Mesencephalon
B. Metencephalon
C. Myelencephalon
D. Rhombencephalon divides into all of the above
A. Mesencephalon
Prosencephalon = Telecephalon and Diencephalon
Rhombencephalon = Metencephalon and Myelencephalon
All of the following Flexures can be found in the 4th EXCEPT:
A. Cephalic
B. Pontine
C. Cervical
D. All fo the above are flexures found in the 4th week
B. Pontine
4th week:
- 3 brain segments (prosencephalon, mesencephalon and rhombencephalon)
- 2 flexures (cephalic and cervical)
5th week:
- 5 brain segments (telecephalon, diacephalon, mesencephalon, metencephalon and myelencephalon)
- 3 flexures (cephalic, cervical and pontine)
Which of the following flexures is located in the mesencephalon?
A. Cephalic
B. Cervical
C. Pontine
D. All of the above
A. Cephalic
Which of the following flexures is located in between the Diacephalon and Metencephalon?
A. Cephalic
B. Cervical
C. Pontine
D. All of the above
A. Cephalic
Note: the segment in between diacephalon and metecephalon is the mesencephalon
Which of the following flexures is located in between the Metencephalon and Myelencephalon?
A. Cephalic
B. Cervical
C. Pontine
D. All of the above
C. Pontine
Which of the following flexures is located in between the Myelencephalon and Spinal cord?
A. Cephalic
B. Cervical
C. Pontine
D. All of the above
B. Cervical
Which of the following is referred to as the Hindbrain?
A. Prosencephalon
B. Mesencephalon
C. Metencephalon
D. Rhombencephalon
E. Myelencephalon
D. Rhombencephalon
Forebrain = Prosencephalon
Midbrain = Mesencephalon
Hindbrain = Rhombencephalon
Which of the following is referred to as the Forebrain?
A. Prosencephalon
B. Mesencephalon
C. Metencephalon
D. Rhombencephalon
E. Myelencephalon
A. Prosencephalon
Forebrain = Prosencephalon
Midbrain = Mesencephalon
Hindbrain = Rhombencephalon
Which of the following is referred to as the Midbrain?
A. Prosencephalon
B. Mesencephalon
C. Metencephalon
D. Rhombencephalon
E. Myelencephalon
B. Mesencephalon
Forebrain = Prosencephalon
Midbrain = Mesencephalon
Hindbrain = Rhombencephalon
Differentiation of ______ is regulated by HOX genes.
Rhombomeres (hindbrain)
(T/F)
The neural canal within each of the segments of the brain expands to form a primitive ventricle.
True
Discuss Neurite Outgrowth:
Neurite Outgrowth
- Axons and dendrites
- Growth cones
- numerous filopodia
- Filopodia regularly extend and retract, testing local environment
note: these are kind of like fingers that reah out and develops connections for the nervous sys via chemoattraction and contactraction
Growth cone is like the hand
Filopodia are like the fingers
The brain stem is made up of all of the following EXCEPT:
A. Myelencephalon
B. Pons
C. Cerebellum
D. Mesencephalon
E. All of the above make up the brain stem
C. Cerebellum
Brain can be divided into two parts:
- Brain stem
- similar in organization to spinal cord
- Made up of myelencephalon, pons (derivative of metencephalon), and mesencephalon
- Higher centers
- Specialized, organization unlike the spinal cord
- Consists of cerebellum (derived from metencephalon) and forebrain
The brain stem is made up of all of the following EXCEPT:
A. Myelencephalon
B. Forebrain
C. Pons
D. Mesencephalon
E. All of the above make up the brain stem
B. Forebrain
Brain stem:
- similar organization to spinal cord
- made up of myelencephalon, pons (derivative of metencephalon) and mesencephalon
Higher centers:
- Not similar to spinal cord organization
- consists of cerebellum and forebrain
Which of the following develops into the cerebrum?
A. Telencephalon
B. Diencephalon
C. Mesencephalon
D. Metencephalon
E. Myelencephalon
A. Telencephalon
Which of the following develops into the medulla oblongata?
A. Telencephalon
B. Diencephalon
C. Mesencephalon
D. Metencephalon
E. Myelencephalon
E. Myelencephalon
Which of the following develops into the cerebellum?
A. Telencephalon
B. Diencephalon
C. Mesencephalon
D. Metencephalon
E. Myelencephalon
D. Metencephalon
Telencephalon = cerebrum
Metencephalon = cerebellum
Myelencephalon = medulla oblongata
Which of the following develops into pons?
A. Telencephalon
B. Diencephalon
C. Mesencephalon
D. Metencephalon
E. Myelencephalon
D. Metencephalon
Metencephalon = pons and cerebellum
Which of the following develops into auditory colliculi?
A. Telencephalon
B. Diencephalon
C. Mesencephalon
D. Metencephalon
E. Myelencephalon
C. Mesencephalon
Telencephalon = cerebrum
Mesencephalon = auditory colliculi
Metencephalon = pons and cerebellum
Myelencephalon = medulla oblongata
All of the following are derived from the Diencephalon EXCEPT:
A. Thalamus
B. Hypothalamus
C. Pineal body
D. Pituitary gland
E. Ears
E. Ears
Diencephalon = Eyes
Which of the following is derived from the Diencephalon?
A. Cerebrum
B. Cerebellum
C. Eyes
D. Pons
E. Medulla oblongata
C. Eyes
Telencephalon = cerebrum
Diencephalon = thalamus, hypothalamus, pineal body, pituitary gland, eyes
Mesencephalon = auditory colliculi
Metencephalon = pons and cerebellum
Myelencephalon = medulla oblongata
Which of the following is the cerebellum derived from?
A. Mesencephalon
B. Metencephalon
C. Myelencephalon
D. Telecephalon
B. Metencephalon
Metencephalon = cerebellum
Telencephalon = cerebrum
Which of the following develops into the anterior (visual) colliculi?
A. Telencephalon
B. Diencephalon
C. Mesencephalon
D. Metencephalon
E. Myelencephalon
C. Mesencephalon
Diencephalon = eyes
Mesencephalon = anterior (visual) and posterior (auditory) colliculi
Which of the following is associated with the Cerebral aqueduct (of Sylvius)?
A. Telencephalon
B. Diencephalon
C. Mesencephalon
D. Metencephalon
E. Myelencephalon
C. Mesencephalon
Which of the following is associated with the cerebral hemispheres (lateral ventricles)?
A. Telencephalon
B. Diencephalon
C. Mesencephalon
D. Metencephalon
E. Myelencephalon
A. Telencephalon
Which of the following is associated with the 3rd ventricle?
A. Telencephalon
B. Diencephalon
C. Mesencephalon
D. Metencephalon
E. Myelencephalon
B. Diencephalon
Diencephalon = 3rd ventricle
Telencephalon = lateral ventricles
Which of the following is associated with the lateral ventricles?
A. Telencephalon
B. Diencephalon
C. Mesencephalon
D. Metencephalon
E. Myelencephalon
A. Telencephalon
Which of the following forms the pineal gland?
A. Telencephalon
B. Diencephalon
C. Mesencephalon
D. Metencephalon
E. Myelencephalon
B. Diencephalon
note: the pineal gland secretes melatonin
note: the pineal gland forms from a midline diverticulum of the epithalamic roof plate
Which of the following forms the pituitary gland?
A. Telencephalon
B. Diencephalon
C. Mesencephalon
D. Metencephalon
E. Myelencephalon
B. Diencephalon
Which of the following forms the thalamus and hypothalamus?
A. Telencephalon
B. Diencephalon
C. Mesencephalon
D. Metencephalon
E. Myelencephalon
B. Diencephalon
Discuss the development of the Pituitary Gland:
Development of the Pituitary Gland:
- The Infundibulum develops from the floor of the 3rd ventricle
- Distal portion forms neurohypophysis (posterior pituitary)
-
Rathke’s pouch forms from an ectoderm lined space near thee future mouth opening
- Differentiates to form the adenohypophysis (forms anterior pituitary and pars intermedia)
During the development of the pituitary gland, which of the following develops into the neurohypophysis?
A. Infundibulum
B. Rathke’s pouch
A. Infundibulum
Infundibulum = neurohypophysis = posterior pituitary
Rathke’s pouch = adenohypophysis = anterior pituitary
During the development of the pituitary gland, which of the following develops into the adenohypophysis?
A. Infundibulum
B. Rathke’s pouch
B. Rathke’s pouch
Infundibulum = neurohypophysis = posterior pituitary
Rathke’s pouch = adenohypophysis = anterior pituitary
Which of the following develops into the anterior pituitary?
A. Neurohypophysis
B. Adenohypophysis
B. Adenohypophysis
Anterior pituitary = adenohypophysis
Posterior pituitary = neurohypophysis
Which of the following develops into the Posterior pituitary?
A. Neurohypophysis
B. Adenohypophysis
A. Neurohypophysis
Infundibulum = neurohypophysis = posterior pituitary
Rathke’s pouch = adenohypophysis = anterior pituitary
Discuss the Mesencephalon:
- Largely made up of _______.
- What does it connect the forebrain to?
- Discuss hydrocephalus in regards to cerebral aqueduct:
Mesencephalon
- Largely made up of white matter
- Forms tracts connecting the forebrain with the hindbrain and spinal cord
- Cerebral aqueduct (central canal)
-
Hydrocephalus:
- the cerebral aqueduct allows CSF to flow from the forebrain to the 4th ventricle
- Hydrocephalus (water on the brain) results if cerebral aqueduct becomes blocked
- 3rd plus lateral ventricles swollen
- Thin cerebral cortex
- Sutures of skull forced apart allowing the bones to increase in size
_______ is largely made up of white matter, specifically tracts connecting the forebrain with the hindbrain and spinal cord.
A. Telencephalon
B. Diencephalon
C. Mesencephalon
D. Metencephalon
E. Myelencephalon
C. Mesencephalon
Discuss Hydrocephalus (water on the brain):
- What causes hydrocephalus?
- How is hydrocephalus treated?
Hydrocephalus (water on the brain):
- Hydrocephalus results if the cerebral aqueduct (of the mesencephalon) becomes blocked
- Medical devices known as VP and VA shunts relieves accumulation of CSF.
Which of the following functions to relay signals linking the spinal cord and cerebral cortex with the cerebellum?
A. Medulla oblongata
B. Pons
C. Thalamus
D. Hypothalamus
E. Cerebellum
B. Pons
______ forms from alar plates of the metencephalon and functions as a center for balance and posture.
A. Medulla oblongata
B. Pons
C. Cerebrum
D. Hypothalamus
E. Cerebellum
E. Cerebellum
Which of the following forms from the myelencephalon and functions as a relay center between the spinal cord and higher brain centers?
A. Medulla oblongata
B. Pons
C. Cerebrum
D. Hypothalamus
E. Cerebellum
A. Medulla oblongata
Medulla oblongata = relay center between spinal cord and higher brain centers
Pons = relays signals linking the spinal cord and cerebral corex w/ the cerebellum
Which of the following functions as a center for balance and posture?
A. Medulla oblongata
B. Pons
C. Cerebrum
D. Hypothalamus
E. Cerebellum
E. Cerebellum
Which of the following regulates respiration, hearbeat, and reflex movements?
A. Medulla oblongata
B. Pons
C. Cerebrum
D. Hypothalamus
E. Cerebellum
A. Medulla oblongata
Cerebellum = balance and posture
Medulla oblongata = regulates respiration, heartbeat and reflex movement
Discuss peripheral nerves:
Peripheral nerves:
- Outgrowth of axons from motor neuroblasts (neuroepithelium) in the basal plate
- Neural Crest Cells (NCCs) form spinal ganglion (sympathetic and parasympathetic ganglion)
- Growth of dendrites toward periphery
- Growth of axons toward dorsal horn
- Interneurons form between sensory neuron termination and motor neurons
- Reflex arc is formed:
* sensory information —> motor response
___________ form all of the sympathetic and parasympathetic ganglia.
Neural Crest Cells (NCCs)
Discuss Hirschsprung’s Disease:
Hirschsprung’s Disease
Symptoms: complete constipation in newborns
Cause: lack of colonization of NCCs in wall of lower colon (parasympathetic)
Result: lack of parasympathetic innervation, no peristalsis
(T/F)
Neurite outgrowth occurs in the CNS but does not occur in the PNS.
False
note: neurite outgrowth occurs in both CNS and PNS
(T/F)
Axon outgrowth occurs in the PNS but does not occur in the CNS.
True
Neurite outgrowth = CNS and PNS
Axon outgrowth = PNS only
Discuss Axon outgrowth:
Axon Outgrowth
- Pioneering axon (filopodia that reaches out first)
- precedes the other in growing toward the target
- Other axons follow
- Forms bundles of axons (fascicles)
- fasciculation
All fascicles of a nerve are enclosed by a _____ (loose collagenous CT).
A. Endoneurium
B. Perineurium
C. Epineurium
D. All of the above
C. Epineurium
Bundles of axons that form during axon outgrowth are known as _______.
Fascicles
Fascicles = bundles of axons
Each axon is surrounded by _____ (loose vascular tissue).
A. Endoneurium
B. Perineurium
C. Epineurium
D. All of the above
A. Endoneurium
Group of fibers are bound together into bundles (fascicles) by a ______ (robust and collagenous).
A. Endoneurium
B. Perineurium
C. Epineurium
D. All of the above
B. Perineurium
Discuss each of the following:
- Endoneurium
- Perineurium
- Epineurium
Axons are surrounded by endoneurium
Bundles of axons (Fascicles) are bound together by perineurium
All fascicles of a nerve are enclosed by a epineurium
Discuss the stabilization of the PNS:
- Interaction between neuron and target structure influence connection type and number
- Apoptosis
- Eliminates axons that fail to reach normal target
- Reduces size of neuronal pool to match target or presynaptic input
- Eliminates connection errors
note: left handed or right handed is determined in utero
Discuss Neural Crest Cells (NCCs):
- NCCs originate from ______.
- Discuss the migration of NCCs:
- Discuss the Differentiation of NCCs:
Neural Crest Cells (NCCs)
- NCCs originate from lateral margins of neural plate
- Migrate as mesenchymal cells; SEM
- change shape (EMT)
- Lose CAMs (cell adhesion molecules)
- Gain integrins (matrix adhesion molecules)
- Travel through well-defined pathways
- CAMs often re-expressed at destination
- Differentiation
- equal developmental potential —> differentiation determined by environment
- Preprogrammed before migration —> differentiation determined by internal factors
- Both of the abnove are true
Discuss the 3 main divisions of Neural Crest:
- Cranial NCC
- Circumpharyngeal NCC
- Trunk NCC
1. Cranial NCC
- cranial NCCs leave before closure of NT
- Origin specifies destination (unlike trunk NCC)
- Responsible for tissues of the facial region
2. Circumpharyngeal NCC
- Vagal crest cells
- migrate into developing gut
- precursors to parasympathetic innervation
- Cardiac crest cells
- outflow tract of the heart and great vessels
- associated with thymus, thyroid and parathyroid
3. Trunk NCC
- Trunk NCCs leave after NT closes
- sixth somite —> caudal
- Three main pathways
- Dorsolateral = melanocytes
- Ventrolateral = sensory ganglia
- Ventral = sympathoadrenal (adrenal chromaffin cells, sympathetic ganglia, sympathetic neurons)
Discuss the cranial division of NCCs:
Cranial NCCs
- cranial NCCs leave before closure of NT
- Origin specifies destination (unlike trunk NCC)
- Responsible for tissues of the facial region
Discuss circumpharyngeal NCCs:
Circumpharyngeal NCC
-
Vagal crest cells
- migrate into developing gut
- precursors to parasympathetic innervation
-
Cardiac crest cells
- outflow tract of the heart and great vessels
- associated with thymus, thyroid and parathyroid
Discuss the Trunk division of NCCs:
Trunk NCC
- Trunk NCCs leave after NT closes
- sixth somite —> caudal
Three main pathways:
- Dorsolateral = melanocytes
- Ventrolateral = sensory ganglia
- Ventral = sympathoadrenal (adrenal chromaffin cells, sympathetic ganglia, sympathetic neurons)
Discuss Neurocristopathies:
Neurocristopathies
- Defects of neural crest cell development
- Neurofibromatosis (peripheral nerve tumors)
- Charcot-Marie-Tooth (demyelinating disease)
- Albinism (pigmentation defect)
- Hirschsprung disease (absence of innervation to the terminal part of the colon) (megacolon)
- DiGeorge Syndrome (affect development of craniofacial and cardiovascular system)
