Development of the Nervous system Flashcards
What does the myotome and splanchnic form?
Myotome forms the skeletal muscle only, splanchnic forms the smooth and cardiac muscle (visceral)
What is made above the 4th somite before neurulation and below the 5th somite?
Above the 4th is the brain, below the 5th is the spinal cord
What is considered to be part of the central nervous system (CNS)?
Anything enclosed within the brain/vertebral column, including brain and spinal cord
What is considered to be part of the peripheral nervous system (PNS) and what are some examples?
Starts in spinal cord/brain, but goes outside of it to muscle or skin, or a sensory nerve on the muscle or skin that goes back to the brain.
Cranial nerves, spinal nerves, ganglia (collection of cell bodies), enteric plexus, sensory receptors (finger tips/skin)
What are the two categories of the peripheral nervous system?
Somatic Autonomic
What is important of the somatic nervous system?
Means body… has motor and sensory portions which are voluntary/you are conscious of (medial, radial ulnar N.)
What is important of the autonomic system?
Has motor and sensory neurons (ignored)
Parasympathetic and Sympathetic
unconscious and involuntary (heart beat)
What is grey matter of the adult spinal cord and what is it made up of?
It is the location of cell bodies of neurons and is made up of dorsal (posterior) horns: sensory neurons, lateral horns: autonomics, anterior (ventral) horns: motor neurons
Where do you see lateral horns mostly (vertebrae wise)?
T1 to L2
What is white matter of the adult spinal cord and what does it consist of?
White matter is where axons are located and they are myelinated (unlike grey matter).
Dorsal (post) funiculus: sensory
Lateral funiculus: sensory and motor
Anterior (ventral) funiculus: motor
The neural plate/tube is divided into two different parts, A and B. What are they and what do they become?
A is Alar plate, becomes sensory neurons that stay in the CNS and never leave (remember neural crest cells are sensory at distance, not inside CNS)
B is Basal plate, becomes motor neurons, lower skeletal and pre-ganglionic/synaptic
how are the alar and basal plate divided?
Sulcus limitans
Afferent vs. Efferent?
Afferent are sensory neurons
Efferent are motor neurons
What does the neural canal/ central canal become?
Ventricular system (in future)
What are the 3 different zones of the spinal cord?
Ventricular zone, closest to the central canal
intermediate zone/matle layer, becomes grey matter
Marginal zone, becomes white matter
The ventricular zone gives rise to stems cells. What are the options for the development of the stem cells?
The can rise up to the intermediate zone or they will stay in the ventricular zone and give rise to ependymoblast to ependymal cell (line ventricular and cell) to the choroid plexus cell which makes cerebral spinal fluid (CSF) derived from neural tube
What does the intermediate zone of the spinal cord contain?
GREY MATTER Astrocytes (regulate microenvironment), neurons
What does the marginal zone of the spinal cord contain?
WHITE MATTER: Oligodendrocytes myelinate cells/axons in the CNS (schwaan from crest myelinate cells in PNS)
What does the neural tube (nueroectoderm) give rise to?
Axons, astrocytes, oligodendrocytes, ependyma cells and choroid plexus (CFS!!)
Where do microglial cells come from?
From mesoderm/mesenchymal cells
monocytes from brain become microglial