Nervous and Sensory Systems Flashcards
What is essential for coordination of different systems with the nervous system?
synapses
What were the first to develop a nerve net?
cnidarians
How did the Cambrian Explosion affect the nervous system?
appearance of specialized nervous systems, became more complex
What are ganglia?
concentrated regions of neurons evolved with bilateral symmetry, allowing many signals to be compared/processed together
What did ganglia lead to?
development of the central nervous system
What is cephalization?
clustering sensory organs and interneurons at the front of the body
facilitated evolution of head region, the brain, and the CNS
Where is the longitudinal nerve cord located in invertebrates?
ventral (below)
Where is the longitudinal nerve cord located in chordates?
dorsal (above) the spinal cord in vertebrates
What are nerves?
groups of neurons with similar functions with axons that are bundled together
evolved due to advantage of neurons with similar wiring taking shortest path to target
What is a reflex?
the body’s automatic response to certain stimuli
What does the CNS consist of?
the brain and spinal cord
What does the PNS consist of?
nerves and glangia
What is grey matter of the brain?
neuron cell bodies, dendrites, unmyelinated axons
What is white matter of the brain?
bundles of nerve fibers with myelinated axons
What are the four main areas of the brain?
brainstem
diencephalon
cerebellum
cerebum
What is the brainstem?
coordinates and conducts information between brain centers
controls and integrates some basal functions, like respiration and cardiovascular control
What is the diencephalon?
neuroendocrine tissue like the hypothalamus, pituitary
regulates homeostasis
basic survival behaviors such as feeding, fighting, fleeing, and reproduction
relay center for the cerebrum
What is the cerebellum?
coordination and error checking during motor, perceptual, and cognitive functions.
also involved in learning and remembering motor skills
What is the cerebrum?
largest and most complex part of the brain
primary sensory areas where information is integrated
voluntary movement of skeletal muscles
cognitive functions like thought, language, speech, and learning
What does vertebrate sensory PNS form from?
neural crest cells: specialized ectodermal cells that develop, separate, and migrate during neural tube formation
form numerous tissues, including sensory neuron in the PNS
What does the PNS do?
transmits information to and from the CNS
What are cranial nerves?
originate in the brain and mostly terminate in the head and upper body
What are spinal nerves?
originate in the spinal cord and extend to parts of the body below the head
What are afferent neurons?
transmit information towards the CNS (sensory neurons)
What are efferent neurons?
transmit signals away from the CNS (output response neurons)
What are mechanosensors?
neurons that have receptors designed to cause a depolarization when there are changes in membrane pressure, vibration, movement
What are thermosensors?
specialized membrane proteins that change conformation with temperature
What are nociceptors?
detect noxious, chemical (pain receptors)
What are gustatory receptors?
neurons with ligand gated ion channels that open in when binding to a particular tastant
What are olfactory receptors?
neurons with ligand gated ion channels that open in when binding to a particular odorant
What do photoreceptors have? How do they behave?
they have special membrane protein with Rhodopsin
changes shape when light hits it
What are the two efferent systems?
Autonomic and Motor
What is the Autonomic system?
regulates an organism’s internal environment in an involuntary manner
sympathetic: fight or flight
parasympathetic: promotes rest and digest responses
enteric: controls digestions, pancreas, gallbladder
What is the motor system?
carries signals from the CNS, and to the skeletal muscles
under voluntary control
