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
Sympathetic nervous system
can accelerate heart rate, widen airways, decrease motility of the large intestine, constrict blood vessels, increase peristalsis in the esophagus, cause pupillary dilation, piloerection (goose bumps) and perspiration (sweating), and raise blood pressure
Parasympathetic nervous system
associated with returning the body to routine, day-to-day operations (coming back down from sympathetic nervous response)
Enteric nervous system
consists of a mesh-like system of neurons that governs the function of the gastrointestinal tract
Why is sexual response part of PNS?
Relaxation required to get blood to reproductive organs
Brain stem
Consists of midbrain, pons, and medulla oblongata (responsible for many vital functions of life, such as breathing, consciousness, blood pressure, heart rate, and sleep)
Midbrain
serves important functions in motor movement, particularly movements of the eye, and in auditory and visual processing
Pons
critical role in generating the respiratory rhythm of breathing
Medulla oblongata
plays an essential role in passing messages between your spinal cord and brain; essential for regulating your cardiovascular and respiratory systems
Hypothalamus
Important for homeostasis
