3.5 - the nervous sytem Flashcards
state the components of a nervous response
- receptors
- effectors
- nervous system or hormones transfer information from receptors to effectors
name the 2 main divisions of the nervous system
- central nervous system (CNS)
- peripheral nervous system (PNS)
outline the gross structure of the mammalian nervous system
peripheral:
- voluntary
- automatic:
— sympathetic
— parasympathetic
central:
- spinal cord
- brain
what’s the CNS
brain + spinal cord
what’s the PNS
pair of nerves originating from CNS + carry nerve impulses into + out of CNS
what’s the dorsal root
- one of 2 roots that emerges from spinal cord
- travels to dorsal root ganglion
- sensory neurones enter spinal cord via dorsal root
what’s the ventral root
- one of 2 roots emerging from spinal cord
- motor neurones leave spinal cord via ventral root
what’s a reflex
rapid, automatic response to sensory stimulus by body
serves as protective mechanism
outline a simple reflex arc
stimulus → receptor → sensory neurone → relay neurone (in CNS) → motor neurone → effector → response
how does a reaction differ from a reflex
- reaction is voluntary + coordinated by brain
- reflex is non-voluntary + doesn’t involve the brain
what’s a nerve net
- simplest form of nervous system found in Cnidarians
- consists of interconnected nerve cells w/ short extensions allowing response to limited number of stimuli
state the 3 types of functional neurones
- sensory neurone
- relay neurone
- motor neurone
state the function of a sensory neurone
carries nerve impulses from receptors to CNS via dorsal root
state the function of a motor neurone
carries nerve impulses from CNS to effectors via ventral root
describe the structure of a motor neurone
- short dendrites carry impulses from CNS to cell body
- cell body found at one end of neurone
- long axon carries impulses from cell body to effectors
state the function of a relay neurone
- located in spinal cord
- links sensory neurone to motor neurone
what’s te function of dendrites
- short, branched extensions of cell body
- receive nerve impulses from other neurones
describe the cell body
region of neurone that contains organelles, notably nucleus + RER
what’s the function of the axon
long fibre that conducts nerve impulses away from cell body