Flashcards in Topic 18: Nervous System Organization Deck (45):
What does the nervous system enable organisms to do?
sense and react to the enviornment
What kind of nervous system structure do cniderians have?
nerve net: interconnected neurons for movement
What kind of nervous system do echinoderms have?
nerve ring: central control structure
What are the nervous system components of bilaterians?
lots of variation
- eyespots that detect light
ladder type nervous system
- 2 longitudinal nerve cords
segmentally arranged clusters of neurons
What are the main components of the CNS?
brain and spinal cord
What are the main components of the PNS?
nerves and ganglia
What are neurons? What do they do?
basic functional unit of nervous system
conduct electrical signals, integrate information
What does the cell body contain?
What are dendrites?
cytoplasmic extensions from cell body - usually many, short
What are axons? What do they do?
cytoplasmic extensions from cell body
What is the axon hillock?
base of axon, where signals are generated
What are glial cells? What do they do?
non-neuron cells of the nervous system
- neuron support, protection, maintenance
- embryonic NS development
What is myelin sheath? What is its purpose?
bundles of insulation around axons
What is myelin sheath produced by in CNS?
What is myelin sheath produced by in PNS?
What do radia glia do?
form tracks in developing embryos
-> help newly formed neurons migrate from neural tube
Where are interneurons found and what do they do?
in the CNS
responsible for integration and processing of information
What is gray matter mostly composed of?
neuron cell bodies
What is white matter mostly composed of?
What is the brain composed of?
ventricles with cerebrospinal fluid
Where is the spinal cord located?
within the spine
What is the function of the spinal cord?
links brain and the rest of us
transmits impulses to/from brain
What is the structure of the spinal cord?
small central canal with cerebrospinal fluid
gray matter surrounds canal - inside
white matter surrounds gray - outside
What are reflex actions?
rapid, involuntary response to stimulus
(knee jerk reflex)
What does the PNS do?
transmits info to/from CNS
What are nerves?
axons of many neurons held together with connective tissue
What do afferent neurons do?
send info from sensory receptor to CNS
What are the two types of senses?
visceral and somatic
Describe visceral senses
senses you aren't aware of
blood pressure, thyroid, hormone levels
Describe somatic senses
senses you are aware of
vision, hearing, taste, etc
What do efferent neurons do?
send info from CNS to effectors: no receptors
target the motor system and autonomic NS
How does the motor system work?
efferent neurons -> skeletal muscle
voluntary and reflexes
How does the autonomic nervous system work?
efferent neurons -> glands, heart, smooth muscle
What are the 3 divisions of the autonomic nervous system?
enteric: controls digestive tract, pancreas, gall bladder
parasympathetic: "rest and digest"
sympathetic: "fight or flight"
What are the 3 broad regions of brains?
forebrain, midbrain, hindbrain
What does the forebrain control?
sensory input, learning, complex processing
What does the midbrain control?
coordinates routing of sensory input
What does the hindbrain control?
Where is the cerebrum derived from? What does it control?
most prominent part of the brain
learning, emotion, memory, perception
What is the corpus callosum?
thick band of axons, connects 2 halves
Where is the cerebellum derived from? What does it control?
motor skills/ coordination
Where is the diencephalon derived from? What does it include?
thalamus: routes sensory info to correct part of cerebrum
hypothalamus: regulates homeostaisis
What does the brainstem do?
control basic life functions - respiration, heartbeat, blood pressure