Nervous System 1 Flashcards
Brain facts
Softest part of human body
Weighs less than 1 pound at birth and about 3 pounds for adults
Makes up to 2% of total body weight
Two major cell types of the nervous system
Glial cells
Neurons
Glial cells
10 to 50 times greater in number
Some form synaptic connections, and transmit signals
Neurons
Larger in size, but less in number
Transmit signals
Astrocytes (most numerous, Star-liked shaped)
Provide structural support
Connected to capillaries and provide nutrients to neurons
Regulate synaptic activity by taking in used neurotransmitters and recycling them
Form the blood brain barrier
Schwann cells
Myelinate axons of peripheral nervous system neurons.
Each cell wrap itself multiple times around the axon to form a single segment of myelin
What myelinates CNS neurons
Oligodendrocytes
Microglial phagocytes
Active during nervous system infections and disease diseases (Parkinson’s)
Recycled dead cells/debris, and isolate scarred areas
Radial glial cells
Form cylindrical tubes to guide and feed newly born neurons as they move from the neural crest to their destination sites
What glial cell produces CSF
Ependymal cells
Ependymal cells
Form a thin, single layered epithelial membrane that lines the interior surface of all brain ventricles
They form a larger structure, called the chordal plexus
Primary sensory neurons
Afferent - carry sensory information from the periphery of the body to the CNS
Motor neurons
Efferent - carry information from the brain to the muscles / stimulate muscles to produce movement
Interneurons
Provide communication between neurons
Basic anatomical structure of neurons
Dendrites
Cell body
Axon hillock
Axon
Terminal branches of axon
The cell body(soma)
It houses the nucleus(has the DNA) and most organelles of the neuron
Specific parts of it have receptor channels and form synapses with the synaptic terminals of other cells
Axosomatic synapse
Terminal branches of axon connects to receptor channels of the cell body
Axodendritic synapse
Terminal branches of axon connect to dendrites
Axoaxonic synapse
Terminal branches of axon connects to terminal branches of axon
Dendrites
House receptor channels, and form synapses with the terminals of other neurons
