Chapter 49: Nervous Systems Flashcards
Unspecialized nervous system
No brain (Ex: hydra, sea star, chitins)
Specialized nervous system
Has brain(s) and cephalization
Cephalization
the concentration of sense organs, nervous control, etc., at the anterior end of the body, forming a head and brain, both during evolution and in the course of an embryo’s development
Gray matter
Regions of clustered neuron cell bodies within the CNS. (unmyelinated neurons)
White matter
the tissue through which messages pass between different areas of grey matter within the central nervous system. (myelinated neurons)
Which type of matter has a higher action potential?
White matter
Why is white matter white?
The white matter is white because of the fatty substance (myelin) that surrounds the nerve fibers (axons).
Spinal cord
conveys information and provide (automatic) responses independent of the brain
Cerebrospinal fluid
Provides protection and buoyancy
Why is buoyancy important for the spinal cord?
The brain is much heavier than the spinal cord (1400 g vs. 25 g)
Afferent neurons
Deals with sensory information; sends info to the CNS
Efferent neurons
Tasked with doing something; sends info to the PNS
Motor system
Control skeletal muscles
Autonomic nervous system
Controls involuntary processes (i.e. heart rate, blood pressure, respiration)
3 divisions of autonomic nervous system
- Parasympathetic
- Sympathetic
- Enteric