001 Nervous System Development Flashcards
• describe the general function of the nervous system
o Consists of the structures in the body that are composed of neural tissue
o Functions
Correlate the adjustments and reactions of an organism to internal and environmental conditions
• list and describe the anatomic parts of the nervous system
Central Nervous System (CNS) • Consists of o the brain (encephalon) o Spinal cord (spinal medulla) • Two regions of CNS o Gray matter (darker to the eye) Has more nerve cell bodies Has fewer myelinated processes Neuropil – the mass of fibers in the gray matter o White matter Has more myelinated processes NO nerve cell bodies Peripheral Nervous System (PNS) • Consists of o Nerves (bundles of nerve fibers) o Ganglia (collections of nerve cell bodies in the PNS o Specialized nerve endings (like rods and cones of the retina)
Functional Parts of the nervous system
Autonomic Nervous System (ANS) • Involuntary control of: o Cardiac muscle o Smooth muscle o Glands • Divided into two parts o Sympathetic – energy using o Parasympathetic – energy sparing Somatic Nervous System • Voluntary control of all other structures of the body • Sensory information from all structures of body • Includes: o Skeletal muscles, bones, joints, skin, ears and eyes
Describe nervous tissue
Highly vascularized Neurons (AKA Nerve cells) • Functional units of the nervous system o Receive stimuli o Conduct impulses (action potentials • Made of o Cell bodies (AKA soma or perikaryon) o Processes Axons Dendrites Nerve fibers – long cytoplasmic extensions of a nerve cell (i.e. axons) Nucleus – collection of nerve cell bodies in the CNS Supporting cells • Two types o Neuroglia – supporting cells in CNS Oligodendrocytes Astrocytes Microglia Ependymal cells o Unnamed group of supporting cells in the PNS Schwann cells Satellite cells • Functions o Physically protect neurons because there is no CT in the CNS by providing physical strength o Some help provide electrochemical insulation to the neurons to speed up the velocity of the nerve impulses o Help regulate the metabolic exchange of the neurons to maintain the survival of the neurons
• compare and contrast neural nucleus and ganglion
o Neural nucleus
Collection of cell bodies within the CNS
o Ganglion
Collection of cell bodies within the PNS
What is and What embryonic week does blastocyst formation occur?
hollow ball of cells that are pretty much identical
Week 1
What is and What embryonic week does bilaminar disc formation occur?
End of week 2
Flattened disc of cells with two distinct populations
• Epiblast – cells in the bilaminar disc that actually form the embryo
• Hypoblast – cells that form the support structures of the embryo (placenta)
What is and What embryonic week does trilaminar disc formation occur?
Week 3
Has three distinct cell populations (germ layers developed from the epiblast)
Basis for all adult tissues of the body
What is and What embryonic week does neurulation occur?
Week 3
The process of the formation of the neural tube which becomes the CNS
What is the notochord
Rod of cells that forms directly from the epiblast cells
Defines the primordial axis of the embryo (determines head end from tail end of the embryo)
Basis for the axial skeletal development (vertebral column)
Induces the development of the nervous system (tells the neuroectoderm to form)
• list the three (3) germ layers of the trilaminar disc
o Ectoderm
Surface ectoderm
• Eventually forms the epidermis of the skin
Neuroectoderm
• Forms the nervous system
o Mesoderm
Forms most of the connective tissues and muscles of the body
Forms the cardiovascular system, including blood
Forms the urinary system
o Endoderm (AKA entoderm)
Forms the lining of the respiratory and digestive tracts
• describe the process of neurulation
o First, a longitudinal thickening of the ectoderm in the midline of the dorsal aspect of the embryo known as the neural plate
o Next, the cells on the lateral part of the neural plate pile up to form neural folds
They proliferate, become thicker and migrate dorsally
o Finally, the cells of the neural folds proliferate and migrate so that the two neural folds meet each other dorsally and form an enclosed structure called the neural tube
neural plate
The longitudinally thickened ectoderm in the midline of the dorsal aspect of the embryo
The lateral aspects become thicker and will form neural folds
Neural folds
Formed by the proliferation of the lateral aspects of the neural plate
Neural groove
The longitudinal gap created between the neural folds
Neural tube
Formed when the cells of the neural folds proliferate and migrate enough that the two folds meet each other dorsally
Described as an enclosed tube
• The cranial end of the tube will form the brain
• The caudal portion forms the spinal cord
The cells enclosed are neuroectoderm cells
The cells that did the enclosing are the surface ectoderm cells