3 - Nervous System Flashcards
What is dorsoventral patterning in the nervous system
Dorsal region gives rise to sensory neurones and commissural interneurones; motor neurones develop in the ventral region
What do sensory neurones do
Carry nerve impulses from tissues and organs to the central nervous system (CNS)
What do interneurones do
Transmit impulses between sensory and motor neurones
What do motor neurones do
Carry impulses from the CNS to muscles and glands
Where do nerves and glial cells originate from during development
From vesicles (cavities) within the neural tube, connected to the central canal of the spinal cord
What do neural stem cells give rise to
Neuroblasts (which become neurones) and glioblasts (which become glial cells)
How do neuroblasts migrate
Along radial glial cells to the cortical plate, where they stop
When do glioblasts arise
After neuroblasts, to form glial cells
What is gliogenesis
The formation of glial cells from neural stem cells after neurones are produced
Name the six types of glial cells
Radial glia
Astrocytes
Ependymal cells
Schwann cells
Oligodendrocytes
Microglia
What is the role of radial glia
Aid cell migration from the ventricular zone to the marginal zone; progenitor cells spanning the apical-basal axis
What is the role of astrocytes
Star-shaped cells
Most abundant in the brain
Form a key part of the blood-brain barrier
What is the role of Schwann cells
Glial cells from the neural crest; migrate along developing peripheral nerve fibres to form myelin
What is target-dependent neuronal survival
Neurotrophic factors from targets prevent neuronal apoptosis by being taken up at nerve terminals and transported along axons
What are transition zones in nervous system development
Access points between the CNS and PNS
What do boundary cap cells do
Regulate access between the CNS and PNS at transition zones during spinal cord morphogenesis
What is the CNS
The central nervous system — includes the brain and spinal cord; acts as the body’s integration and command centre
What is the PNS
The peripheral nervous system — includes all peripheral nerves and ganglia; conveys information between the CNS and the rest of the body
What are the two divisions of the PNS
Somatic nervous system (SNS) and autonomic nervous system (ANS)
What does the SNS control
Sensory input from skin, muscles, and joints; motor output to skeletal muscles
What does the ANS control
Involuntary functions via the sympathetic, parasympathetic, and enteric nervous systems
