Lecture 15 - Early Brain Development I Flashcards
Which signals act on the anterior structures and which signals act on posterior structures during development?
Anterior: Wnt Inhibitor, BMP Inhibitor
Posterior: RA, FGF, Wnt, BMP Inhibitor
In the following diagram of the developing brain, what is G?

Cerebral Cortex
Which germ layers forms the skin, nails, hair, lens of eye, lining of the internal and external ear, nose, sinuses, mouth, pituitary gland, and the mammary gland?
Ectoderm
What does the metencephalon become?
Cerebellum and Pons
In the following diagram of the developing brain, what is I?

Spinal Cord
True or False?:
Hensen’s node is found in amphibians. Spemann’s organizer is found in humans and chicks. They are homologus to eachother.
False
Hensen’s node is found in humans and chicks. Spemann’s organizer is found in amphibians. They are homologus to eachother.
In the following diagram of the neural plate being folded into the neural tube, what is J?

Somite
In the following diagram of the developing brain, what is K?

Metencephlon
In the following diagram of the developing brain, what is H?

Spinal Cord
In the following diagram of the developing brain, what is D?

Basal Ganglia
What is a lumbar puncture (spinal tap)?
A lumbar puncture is when a needle is inserted between lumbar vertebrae for the recovery of CSF so that it can be screened for proteins, glucose, and pressure. It is helpful in diagnosing hemorrhage, meningitis, and CNS inflammation.
What are the two phases of inductive signaling from underlying mesoderm?
Activation: Activating signals from early-forming mesoderm induces differentiation of neural plate, but in a default state of anterior differentiation (classical neural induction).
Transformation: Transforming signals coming from late-forming mesoderm induces posterior character to neural tissue.
In the following diagram of the neural tube being sealed, what is D?

Anterior Neural Fold
What structure induces the ectoderm above it to become the neural plate during neurulation?
Notochord
In the following diagram of the neural plate being folded into the neural tube, what is D?

Roofplate
What is spina bifida?
Spina bifida is a birth defect in which there is incomplete closing of the spine and membranes around the spinal cord during early development in pregnancy.
In the following diagram of the developing brain, what is F?

Cervical Flexure
What would happen if you injected chordin mRNA into an embryo?
You would trigger the development of a second nervous system (like in the “organizer” experiment).
In the following diagram of the neural tube being sealed, what is B?

Central Canal
In the following diagram of the neural plate being folded into the neural tube, what is H?

Notochord
In the following diagram of the developing brain, what is G?

Myelencephalon
In the following diagram of the neural tube being sealed, what is A?

Neural Tube
What is the primitive streak?
The primitive streak is the faint streak which is the earliest trace of the embryo in the fertilized ovum of a higher vertebrate.
In the following diagram of the developing brain, what is D?

Mesencephalon
Which secondary brain vesicles does the mesencephalon become?
Mesencephalon
(This is kind of a trick question because the vesicle isn’t subdivided.)
What occurs during gastrulation?
- Formation of the 3 germinal layers.
- Inward migration of cells.
- Creation of the notochord.
In the following diagram of the neural plate being folded into the neural tube, what is E?

Neural Tube
Which germ layer forms the muscles, bones, lymphatic tissue, spleen, blood cells, heart, lungs, reproductive system, excretory system, and the notochord?
Mesoderm
Where is the notochord found?
The notochord starts at the primitive pit (near Hensen’s node/Spemann’s organizer) and elongates under the primitive streak.
What does the mesencephalon become?
Superior and Inferior Colliculus and Fiber Tracts
Which secondary brain vesicles does the rhombencephalon become?
Metencephalon and Myelencephalon
In the following diagram of the developing brain, what is F?

Lateral Ventricles
What do you predict will happen in the following transplantation experiment?
Early-Forming (Anterior): A secondary head is formed.
Late-Forming (Posterior): A secondary tail is formed.
In the following diagram of the neural plate being folded into the neural tube, what is C?

Pre-Somitic Mesoderm
In the following diagram of the developing brain, what is J?

Myelencephalon
Which secondary brain vesicles does the prosencephalon become?
Telencephalon and Diencephalon
How does the neural tube become regionalized?
Induction of neural tissue by mesodermal factors is followed by graded mesodermal signals that help regionalize the neural tissue.
In the following diagram of the developing brain, what is A?

Cerebral Hemisphere
Which germ layer forms the lining of the lungs, tounge, tonsils, urethra and associated glands, bladder, and digestive tract?
Endoderm
In the following diagram of the developing brain, what is A?

Prosencephalon
In the following diagram of the closure of the neural tube, what is D?

Rhombencephalon
What are the primary brain vesicles (in order from furthest to closest to spinal cord)?
Prosencephalon, Mescencephalon, and Rhombencephalon
In the following diagram of the developing brain, what is C?

Lateral Fissure
In the following diagram of the neural tube being sealed, what is E?

Somite
What common problem causes both anencephaly and spina bifida?
Neural Tube Closure Problems
What is anencephaly?
Anencephal is a rare birth defect that occurs early in pregnancy. Infants with anencephaly usually have a brain stem, which controls reflex actions such as breathing, but don’t have a forebrain or cerebrum.
What is neurulation?
Neurulation is the folding process in vertebrate embryos that turns the neural plate into the neural tube.
What are the secondary brain vesicles (in order from furthest to closest to spinal cord)?
Telencephalon, Diencephalon, Mesencephalon, Metencephalon, and Myelencephalon
In the following diagram of the neural plate being folded into the neural tube, what is A?

Mesenchymal Cells
In the following diagram of the developing brain, what is B?

Optic Vesicle
What does the myelencephalon become?
Medulla and Cranial Nerve Nuclei
What are the 4 steps of neurulation?
- Induce formation of the neural plate.
- Fold the neural plate into an elongated structure called the neural tube.
- Seal the neural tube.
- Close the ends of the neural tube.
What is the cerebrospinal fluid responsible for?
- Protection (gravity, injury)
- Homeostasis (electrolytes, etc.)
In the following diagram of the induction of the formation of the neural plate, what is A?

Endoderm
In the following diagram of the closure of the neural tube, what is C?

Anterior Neural Fold
What is the predecessor of adrenergic neurons and cholinergic neurons?
Sympathetic Progenitor
In the following diagram of the developing brain, what is C?

Diencephalon
In the following diagram of the neural plate being folded into the neural tube, what is G?

Neural Groove
In the following diagram of the induction of the formation of the neural plate, what is B?

Mesoderm
In the following diagram of the developing brain, what is H?

Cerebellum
In the following diagram of the induction of the formation of the neural plate, what is F?

Primitive Streak
In the following diagram of the induction of the formation of the neural plate, what is E?

Notochord
In the following diagram of the developing brain, what is C?

Cephalic Flexure
In the following diagram of the developing brain, what is B?

Central Sulcus
What is one of the first signs that the process of gastrulation is going to take place?
Presence of the Primitive Streak
In the following diagram of the induction of the formation of the neural plate, what is C?

Ectoderm
In the following diagram of the developing brain, what is I?

Central Canal
In the following diagram of the developing brain, what is K?

Future Cerebral Aqueduct
How is spina bifida prevented?
Spina bifida is prevented by prescribing folic acid supplements to pregnant women.
In the following diagram of the neural plate being folded into the neural tube, what is I?

Floorplate
What are the 3 germinal layers?
Ectoderm, Mesoderm, and Endoderm
Where is the cerebrospinal fluid produced?
Choroid Plexus
What happened in Mangold and Spemann’s “organizer” experiment?
- Tissue from the dorsal lip of the blastopore (which normally becomes the mesoderm) from an unpigmented donor embryo was transplanted to a recipient pigmented embryo.
- The transplanted tissue caused formation of a secondary embryo.
- Upon closer inspection, transplanted tissue formed additional mesodermal tissue, including a second notochord.
- Importantly, the secondary notochord tissue caused formation of an additional neural plate/tube that was entirely made from host tissue.
In the following diagram of the closure of the neural tube, what is F?

Somites
What does the diencephalon become?
Thalamus, Hypothalamus, and Retina
In the following diagram of the neural tube being sealed, what is C?

Neural Crest
What is hydrocephalus?
Hydrocephalus is a disorder occuring in 1 in 500 live births. It results in head enlargement and separation of cranial bones (especially if before 2 years of age). There are over 180 causes like altered CSF flow, problems with reabsorption, or excessive CSF production. It is classed into communication (non-obstructive) or non-communicating (obstructive). It can be congenital or acquired. Congenital forms are normally caused by development problems resulting in blockade of cerebral aqueduct or foramens. It is treated with a shunt.
In the following diagram of the developing brain, what is L?

Olfactory Bulb
True or False?:
The notochord is a transient structure that becomes part of the vertebral column.
True
In the following diagram of the developing brain, what is M?

Third Ventricle
In the following diagram of the developing brain, what is H?

Spinal Cord
From where do cells inwardly migrate during gastrulation?
Primitive Streak
In the following diagram of the developing brain, what is D?

Optic Vesicle
In the following diagram of the closure of the neural tube, what is E?

Spinal Cord
Which germ layer forms the nervous system?
Ectoderm
In the following diagram of the neural plate being folded into the neural tube, what is F?

Ectoderm
In the following diagram of the developing brain, what is F?

Pontine Flexure
What defines the midline of the embryo?
Notochord
How is it determined which parts of the ectoderm become the nervous system in Drosophila?
Decapentaplegic (dpp) induces a non-neuronal fate to all of the ectoderm. Above the notochord, short gastrulation (sog) is released, which inhibits the dpp signal so that the portion of ectoderm can take on its default neuronal state.
In the following diagram of the closure of the neural tube, what is A?

Neural Tube
In the following diagram of the developing brain, what is E?

Diencephalon (Thalamus)
In the following diagram of the developing brain, what is G?

Cranial and Spinal Ganglia
In the following diagram of the developing brain, what is L?

Lateral Ventricle
In the following diagram of the neural plate being folded into the neural tube, what is B?

Neural Crest
What are the 5 broad events that occur during embryonic development?
- Cell Division and Basic Organization
- Body Plan Formation
- Morphogenesis
- Cell Proliferation/Differentiation
- Growth and Connectivity
In the following diagram of the developing brain, what is E?

Metencephalon
In the following diagram of the developing brain, what is E?

Rhombencephalon
What are the 5 relevant properties of bone morphogenetic proteins (BMPs)?
- They are members of the TGFβ (transforming growth factor β) superfamily of secreted growth factors.
- They are expressed in ectoderm.
- They cause signaling events that promote epidermal cell fate.
- They are inhibited by noggin, chording, and follistatin, thus allowing for neural induction.
- Without active suppression, the cause ectoderm to become epidermis.
In the following diagram of the closure of the neural tube, what is B?

Sensory Ganglion
In the following diagram of the induction of the formation of the neural plate, what is D?

Neural Plate
What does the telencephalon become?
Cerebrum, Olfactory Lobes, and Hippocampus
What is the predecessor of sensory neurons, sympathetic progenitors, melanocytes, and chromaffin cell progenitors?
Neural Crest Progenitor
What do noggin, chordin, and follistatin do?
They are secreted proteins that induce ectoderm to form neural tissue by binding and inhibiting the actions of bone morphogenetic protein (BMP) signaling molecules.
In the following diagram of the developing brain, what is J?

Fourth Ventricle
In the following diagram of the developing brain, what is A?

Telencephalon
In the following diagram of the developing brain, what is B?

Mesencephalon