Anatomy practical 3 - Embryology Flashcards
(50 cards)
What is neurulation?
The formation and closure of the neural tube
What are neural crest cells?
These are cells which differentiate into a number of different cell types to allow the formation of the foetus
What are melanoyctes?
These are pigment producing cells - travel through the dermis into the ectoderm to colonise skin and hair follices
Where does the notochord lie in relation to the ectoderm?
What is the notochord called at the two ends?
The notochord is inferior to the ectoderm and is surrounded by the ectoderm
There is the anterior neuropore located cranially and the posterior neuropore located caudally
What are different caudal neural tube defects?
Spina bifida cystica:
Myelonmeningocele - sac containing both the CSF and the nerves and part of the spinal cord - severe
Meningocele - sac containing jus the CSF and the meninges - less severe
Spina bifida occulata:
One or more vertebrae have malformed
What is a cranial neural tube defect and name the different types
This is if the anterior neuropore does not close correctly
Encephalocoele
Anencephaly
What is ancencephaly?
Serious birth defect - baby is born without parts of the brain and skull
Also have significant abnormalities in the face and the neck
This condition is not compatible with life
How can anencephaly be detected and when?
This can be detected prenatally around 11-14 weeks gestation via ultrasound or usage of the maternal serum to measure AFP level
If the AFP levels are high - suggests that the foetus has an open neural tube defect
What is encephalocoele?
This is the herniation of the meninges and the brain tissue outside of the cranium
Much more rare
What vitamin can reduce the risk of a neural tube defect in pregnancy?
Folic acid
When do the first brain vesicles develop and how many?
The three primary brain vesicles develop during week 4
When to the second lot of brain vesicles develop and how many?
The five secondary brain vesicles develop during week 5
What are the primary brain vesicles?
Forebrain (prosencephalon)
Midbrain (mesencephalon)
Hindbrain (rhombencephalon)
What are the secondary brain vesicles and what do these develop into?
Telecephalon - cerebrum
Diencephalon - thalamus, hypothalamus, epithalamus, retina
Mesencephalon - midbrain
Metencephalon - pons, cerebellum
Myelencephalon - medulla oblongata, spinal cord
What is Hydrocephalus?
What is the cause of this?
This is a dilatation of the cerebral ventricles leading to increased ICP
Due to CSF drainage blockage e.g. at the arachnoid villi or too much CSF being produced
What is a third ventriculostomy?
This is where a small hole is made in the floor of the third ventricle to divert the flow of CSF in incases of raised ICP
What is cerebral palsy?
Most common congenital physical disability - group of non-progressive neuromuscular disorders resulting from brain damage
What is meant by ‘nuchal cord’?
This is when the umbilical chord is coiled around the baby’s neck
What do the mesoderm and the neural crest cells differentiate into?
Mesoderm - differentiates into muscles and arteries
Neural crest cells differentiate into connective tissues and bone
What are pharyngeal arches?
1, 2, 3, 4, 6
Contain mesoderm and neural crest cells and each arch has an associated cranial nerve
Which cranial nerves are associated with which pharyngeal arches?
1 - CNV 2 - CNVII 3 - CNIX 4 - CNX (superior laryngeal nerve) 6 - CNX (recurrent laryngeal )
What is microtia?
Congenital deformity - underdeveloped or absent pinna (external of the ear)
Which pharyngeal arch are external ear defects associated with?
With the first pharyngeal arch
Which arch forms the anterior two thirds of the tongue?
Arch 1
