Section 1
Preview this deck
When does anterior fontanelle close?
Front
| 5 | 0 | ||
| 4 | 0 | ||
| 3 | 0 | ||
| 2 | 0 | ||
| 1 | 0 |
Active users
0
All-time users
0
Favorites
0
Last updated
6 years ago
Date created
Mar 1, 2020
Cards (68)
Section 1
(50 cards)
When does anterior fontanelle close?
by 2.5 years of life
What day is the notochord formed? what does it do?
day 17 and induces the primitive streak to form the neural plate that later develops the neural groove and neural folds
What is a Hamartoma
disorganized cells in the proper location for that cell type
When do the commissures form?
8-17 weeks
When does myelination begin?
fifth fetal month and proceeds caudad to cephalad, dorsal to ventral, and central to peripheral, and sensory before motor
What tissue or structure dictates cleavage of the telencephalon and development of midline facial structures?
prechordal mesoderm
Cleidocranial dysostosis
occurs with retention of mandibular teeth, delayed closure of fontanelles, wormian bones, and midline defects
What does Nissl stain for? What does it bind too?
Neuron cell bodies (binds nucleic acid)
When does posterior neuropore close?
26 days
When does Metopic suture close?
around 1 year
What is the most frequent cephalocele?
Occipital cephalocele—the most frequent among Caucasians and in Europe and North America. There is a female predilection. The cephalocele protrudes between the foramen magnum and the lambdoid suture. It is associated with myelomeningocele (7%), diastematomyelia (3%), Chiari II and III malformations, Dandy-Walker malformation, and Klippel-Feil syndrome
What are Marinesco bodies?
Marinesco bodies are seen in normal brain. They are eosinophilic and contain chiefly ubiquitin. They are located mainly in the nucleus of melanin cells of the brainstem.
What is Arrhinencephaly?
the absence of the olfactory bulbs and tracts with normal cortex and gray matter in place of the corpus callosum. It is associated with holoprosencephaly and Kallmann syndrome (anosmia, hypogonadism, and mental retardation).
When does posterior and sphenoid fontanelles close?
2-3 months
When does secondary neurulation occur? And what does defects of secondary neurulation cause?
4-5 weeks; spinal dysraphisms below L1/2
1. Pachygyria 2. Polymicrogyria
1. overall decreased number of gyri and those that are present are enlarged 2. wrinkled-appearing brain with many small gyri. It forms occasionally after neuronal migration from neural injury. Usually, there are only four layers of cortex in the abnormal gyri. It may be focal or widespread.
What are the two astrocytic reactions to injury and what characterizes them?
1. Secondary (reactive) astrocytosis—occurs after stroke, degenerative diseases, etc. There rarely are mitotic figures unless there is neoplastic disease. Gemistocytic astrocytes are large reactive astrocytes with eccentric nuclei. Fibrillary astrocytes appear later, have smaller cell bodies, and more fibers. Rosenthal fibers are eosinophilic masses in the astrocytic processes and are increased with Alexander disease, pilocytic astrocytomas, and reactive astrocytosis. 2. Primary astrocytosis—the proliferation of astrocytes after astrocytic disease such as hepatic encephalopathy with Alzheimer II astrocytes (large nuclei, gray, glycogen inclusions)
Lissencephaly
smooth brain. In the complete form, the cerebral hemispheres have no sulci. In the incomplete form, there are several shallow sulci. It is associated with in utero infections
What is the main component of astrocytic intermediate filaments?
Glial fibrillary acidic protein (GFAP)
Viral Inclusion bodies
1. Intranuclear—herpes simplex virus 1 (HSV-1; Cowdry type A, eosinophilic, in neurons, astrocytes, and oligodendrocytes; seen early in the disease), cytomegalovirus (CMV), and measles (subacute sclerosing panencephalitis [SSPE]) 2. Intracytoplasmic—rabies (Negri bodies), SSPE, and CMV
Ectopias
neurons in locations brain tissue should not be in (i.e., the subarachnoid space). They are associated with dysraphism and hydranencephaly
Schizencephaly
a gray matter-lined cleft extending from the pia to the ventricle. The cleft may be filled with CSF (opened lip) or collapsed (closed lip)
What are microglia?
macrophages from outside the CNS. With mild injury, there may be rod cells with cigar-shaped nuclei.
What are ependymal cell's reaction or response to injury?
DO NOT proliferate with injury but when damaged are replaced by subependymal astrocytes
What is ferrugination
dead neurons become encrusted with Fe and Ca salts --> red neurons
What is central chromatolysis?
occurs after an injury to an axon near the cell body. The Nissl substance disappears, the nucleus becomes eccentric, and the cell body enlarges. It is seen in the anterior horn cells with anterior nerve root compression and Guillain-Barré syndrome. The cells may progress to death or recover.
What are dermal sinus tracts?
epithelium-lined tracts caused by faulty segmental disjunction. 60% extend from the skin to the spinal canal, although they may end in the subcutaneous tissue, dura, spinal cord, or nerve roots. 50% end in epidermoids or dermoids. More than 50% are lumbar and the next most frequent site is occipital. There is no gender predilection. Symptoms are mainly a result of infection. They are associated with skin dimples, hyperpigmentation, hairy nevi, and capillary malformations.
A problem at what stage causes vascular malformations and neurocutaneous syndromes.
Neuronal proliferation and differentiation
What are the 5 characteristics of progressive or reversible neuronal injury seen?
1. Central chromatolysis 2. Neurofibrillary tangles 3. Neuronal storage of lipids or carbohydrates 4. Inclusion bodies (viral or degenerative/metabolic) 5. Marinesco bodies
When does the anterior neuropore close? what does it form?
24 days - lamina terminalis
During development, if mesenchyme enters the neural tube and forms lipomas and/or lipomyelomeningoceles, what is this called?
Dysjunction
Brain and spinal cord are formed from neuroectoderm at how many weeks?
3-8 weeks
When do the neural folds fuse?
22 days to form the neural tube
True melanin is made by what? and located where?
tyrosinase and located in the leptomeningeal melanocytes of the ventral medulla and cervical cord. (form the primary CNS melanomas)
What do the ectodermal placodes form?
they overly the neural tube and form the olfactory epithelium and cranial nerve 5, 7 to 10 ganglia
What are pia/arachnoid formed from?
neuroectoderm
A problem at what stage causes callosal agenesis, schizencephaly, and heterotopias
Cellular migration
What does silver stain for?
Cell processes
What are Heterotopias?
normal neurons in abnormal CNS locations (i.e., in the centrum semiovale, along the lateral ventricles or in the cerebellar white matter). They may be laminar or nodular and usually do not enhance
Abnormalities at what stage cause holoprosencephaly, septooptic dysplasia, and Dandy-Walker malformation?
Ventral induction
What is dura formed from?
mesodermal elements
Why does partial agenesis of corpus callosum always include rostrum and splenium?
rostrum and splenium are formed last
When does the germinal matrix form? what does it produce? and when does it involute?
7 weeks; produces neurons and glia; 30 weeks
What is a Choristoma
correctly organized cells in the wrong location
What are neurofibrillary tangles?
Argyrophilic linear densities accumulate in the cell bodies and processes. They can be detected on silver stain. The neurofibrils are made up of hyperphosphorylated tau proteins, neurofilaments, and microfilaments (actin). They are much more numerous with Alzheimer disease, postencephalitic Parkinson disease, progressive supranuclear palsy, and aluminum toxicity.
What is Septooptic dysplasia?
(de Morsier syndrome)—occurs with mild lobar holoprosencephaly, absence of the septum pellucidum, schizencephaly, and hypoplastic optic nerves. It is associated with seizures, visual symptoms, hypothalamic-pituitary dysfunction (precocious puberty), enlarged ventricles, and hypotelorism
When does mastoid fontanelle close?
by 1 year
When does primary neurulation occur? and what does it form?
3-4weeks. Neural plate, neural groove, and neural folds
What is ventral induction?
the growing brain's influence on the overlying mesoderm causing it to grow
What is myelomeningocele associated with?
Chiari II malformation (100%), hydrocephalus (80%), lipoma (75%), syringomyelia (50%), diastematomyelia (40%), scoliosis (20%), kyphosis (10%), orthopedic deformities, and callosal dysgenesis
Section 2
(18 cards)