Lecture 3 Embryology study set

What is the red structure in the amniotic sac? Is it apart of the endoderm or ectoderm?

What is the red structure in the amniotic sac? Is it apart of the endoderm or ectoderm?

Neural Plate, ectoderm

What are the 3 layers of the trilaminar germ disc?

Ectoderm, mesoderm, endoderm

The notochord is located in what trilaminar germ disc?

Mesoderm

T/F The yolk sac is located in the Ectoderm

False (endoderm)

What trilaminar layer is the amniotic cavity located?

Ectoderm

What structure is being shown at number 4?

Notochord

What structure is being show a number 1?

Ectoderm/neural plate

Number 3 is showing which structure?

Endoderm

What structure is shown in number 2?

Mesoderm

What is the structure being shown in number 1?

Neural crest

What structure is being shown in number 3?

Neural canal

What structure is being shown in number 5?

Neural tube

What structure is being shown in number 4?

Notochord

What structure is being shown in number 2?

Neural fold

T/F Schwann cells are myelin cells for the PNS

True

T/F the neural tube has neurons, supporting cells, lower motor neurons, and preganglionic autonomic neurons located in the PNS.

False (slide 7)

The cranial part of the embryo is _______ to the fused neural folds. What happens when the cranial part of embryo doesn’t close?

Rostral, the baby is stillborn

In the image, the end of the spinal cord is ______ to the fused neural folds. What happens if that region doesn’t close?

Caudal, spinal bifida occurs

What is the ventral tube called in a developing embryo? Is it sensory or motor?

Basal plate, motor

What is the dorsal tube called in the embryo? Is it sensory or motor?

Alar plate, sensory

T/F When you add the dorsal and ventral nerve roots, they create the spinal cord of the embryo

False (they create the spinal nerves, slide 10)

Identify the structures Labeled 1-3.

1. Prosencephalon

2. Mesencephalon

3. Rhombencephalon

This primary vesicle gives rise to secondary vesicles telencephalon and diencephlon

Prosencephalon

T/F the primary vesicle mesencephalon eventually gives rise to the metencephalon and then the midbrain

False (still mesencephalon)

What adult derivatives comes from the Prosencephalon?

Cerebral cortex, corpus striatum, thalamus, hypothalamus

What adult derivatives come from he mesencephalon?

Midbrain

What adult derivatives com from the Rhombencephalon?

Cerebellum, pons, medulla

The cerebral cortex and corpus striatum arise from what secondary vesicle?

Telencephalon

The cerebellum and pons arise from what secondary vesicle?

Mesencephalon

The myelencephalon gives rise to what adult derivative?

Medulla

The Rhombencephalon gives rise to what secondary vesicles?

Metencephalon and myelencephalon

The Prosencephalon gives rise to what secondary vesicles?

Telencephalon and diencephalon

This structure contains the lateral ventricles

Telencephalon (hemispheres)

Which structure contains the third ventricle in the ventricular system?

Diencephalon

What structure contains the cerebral aqueduct in the ventricular system?

Mesencephalon (midbrain)

At what point during fetal development does the frontal, parietal, temporal, and occipital lobes are identifiable?

week 14

At what point during fetal development do we see the lateral, central, and calcarine sulcus?

Week 28

This condition is characterized by excess CSF in the ventricular system due to an imbalance between production and absorption of CSF.

Hydrocephalus

What are some causes for hydrocephalus

Arnold-Chiari malformation, congenital aqueductal stenosis, meningitis

This malformation describes the foramina being obstructed from the 4th ventricle to subarachnoid space. This is one of the causes for what condition?

Arnold-chairing malformation, hydrocephalus

This condition is characterized by inflammation of the meninges

Meningitis

Which brain is considered hydrocephalic? How can you tell?

Right brain, excess fluid in the lateral ventricles

This condition causes atrophy of cerebral cortex and white matter, thinning of bones in calvaria, prominent forehead, and compression of basal ganglia and diencephalon.

Hydrocephalus

How would we treat hydrocephalus?

Early prevention, pressure sensitive catheter/shunt into internal jugular vein

What condition is being treated in the image below?

Hydrocephalus

This condition is the most common congenital anomaly involving the lower brain stem and the cerebrum

Arnold-Chiari malformation

What is another name for Arnold-Chiari malformation

Chiari malformation

This condition is characterized by a structural defect of the cerebellum and herniation of the medulla causing part of cerebellum to go through foramen magnum.

Arnold-Chiari malformation

T/F Arnold-chiari malformation may cause hydrocephalus.

True

How often does Arnold-Chiari malformation occur and what conditions are associated with it?

Occurs 1/1000 births, spina bifida and lumbar meningomyelocele

What are some signs and symptoms of Arnold-Chiari Malformation?

Neck pain, balance problems, muscle weakness

T/F Hand coordination and fine motor skills may be affected with Arnold-Chiari malformation

True

What is happening in this image? What condition is causing this?

Cerebellum is plugging the foramen magnum, Arnold-Chiari malformation

What structure is shown in number 1?

Anterior fontaneal

What structure is shown in number 2?

Sphenoid fontaneal

What structure is shown in image 3?

Mastoid fontanel

What structure is shown in number 4?

Posterior fonatnel

What structure is shown in number 5?

Posterior fontanel

What structure is shown in number 6?

Anterior fontanel

What is the cause of microencephaly

Premature closing of fontanelles and sutures

T/F Even though the sutures and fontanelles close prematurely in a patient with microcephaly, the brain is fully developed. (Slide 33)

False

What are some side effects of microcephaly?

Gross cognitive impairment, poor motor function, seizures, dwarfism

This neural tube defect is caused by a failure to close the entire neural tube.

Craniorachischisis

What is another name for craniorachischisis?

Total dysraphism

This defect is caused by a failure of the cranial neural tube to close during development?

Cranioschisis

Neural defect where the neural tube doesn’t fully close and leaves the entire lower spinal cord open

Rachischisis

This neural defect is caused by a failure of closure of the anterior neuropore causing Acrania

Anencephaly

T/F Anencephaly is a condition that happens in the late 2nd trimester, gives the fetus a “frog-like” appearance. (Slide 35)

False

What condition is shown in the image below

Anencephaly

What is another term used to describe Anencephaly?

Cranioschisis

This is the most common severe anomaly seen in stillborn fetuses, making up ½ of the severe neural tube defects.

Anencephaly

Wha are some causes of anencephaly?

genetic factors, high exposure to nickel, chromium, lead, and mercury

This condition can be induced by rats by teratogenic agents

Anencephaly

What are some prevention methods we can use to treat anencephaly?

Folic acid= up to 0.4 mg/day before pregnancy

T/f You should take 0.4 mg/day of folic acid during your pregnancy to reduce the risk of Anencephaly (slide 38)

False

What are some ways we can diagnose Anencephaly

Ultrasound, alpha-fetoproteins in amniotic fluid

T/F When we look at Alpha-fetoproteins in amniotic fluid, we often see a decrease in neural tube defect and an increase in patients with Down syndrome (Slide 38)

false

This condition is characterized by a sac-like protrusion of the cerebrum and meninges through a skull defect. Where does this condition commonly occur? (Slide 39) 2-part question

Encephalocele; in the Occiput, top of the head, Forehead-nose junction

What condition is being shown in the image below?

Encephalocele

This condition is caused by a nonfusion of the embryonic halves of the vertebral arches during the 4th week of development

Spina bifida

What are the types of spina bifida that are present with a cyst?

Spina Bifida Meningomyelocele, Spina Bifida Meningocele

What are the types of spina bifid that are considered closed?

Spina Bifida occulta

List the spina bifida that are considered open (aperta).

Spina bifida myelocele, spina bifida meningocele, spina bifida meningomyelocele

This neural tube defect is usually asymptomatic and occurs in L5 or S1 in about 10% of otherwise normal people.

spina bifida occulta

This neural tube defect is characterized by a small dimple with a tuff of hair, a small percentage of cases may have functional defects.

spina bifida occulta

What condition is being shown in the image below?

Spina bifida occulta

This is the most severe form of spina bifida

Spina bifida myelocele (rachischisis)

This neural tube defect is characterized by neural folds remaining open, causing CSF to leak out.

Spina bifida Myelocele (rachischisis)

T/F Patients with spina bifida myelocele have a strong clinical outlook (slide 43)

False

This neural tube defect is characterized by a cyst-like sac covered by skin or easily ruptured membrane, most commonly found in the lumbar region.

Spina bifida cystica

T/F Of the different types of spina Bifida cystica, 10% are menigoceles and 90% are considered meningomyeloceles. (Slide 44)

True

T/F Of the different types of spina Bifida cystica, 90% are menigoceles and 10% are considered meningomyeloceles. (Slide 44)

False

What are some possible causes of spina bifida cystica?

Obesity, Diabetic/anticonvulsant meds, fever during neural tube development

What condition is shown in the images below?

Spina bifida meningocele

This neural tub defect is characterized by a protrusion through a defect in the vertebral arch

Spina bifida meningocele

T/F in a spina bifida meningocele, the neural structures are intact, in normal position, and has low alpha-fetoproteins (slide 46)

False

This neural tube defect is characterized by a protrusion of meninges and spinal cord through a defect in the vertebral arch.

Spina Bifida meningomyelocele

This type of neural tube defect is more serious than a meningocele and causes paralysis in the lower limb, bladder, and bowel.

Spina bifida meningomyelocele

T/F The spina bifida meningomyelocele causes marked neurologic defects superior to the level of the cyst (slide 48)

False (inferior)

What neural tube defect is shown in the image below

Spina bifida meningomyelocele