Unit 3 The Nervious System Flashcards
(28 cards)
What is the central nervous system made of
Brain, spinal cord
What is the peripheral system made of
Spinal nerves, cranial nerves and there roots and branches.
What does the system do
Responds to internal and external environments
what is a stimulus
a change
what does the nervous system do
-stimulus causes change
-Receptors detect changes
-nervous system transmits impulses to an effector
-Effectors cause the response.
what is an effector
effector is a muscle or a gland, such as an endocrine gland.
how are Endocrine responses different
Endocrine responses are slower but longer lived than nervous responses
where is the spinal cord
in the middle of the vertebrae
what is the spinal cord surrounded by
three membranes collectively called the meninges.
what is the white part of the spinal cord called
white matter
what is the inner potion of the spinal cord made of
grey matter
what is white matter made of
myelinated neurons
what is grey matter made of
contains many nuclei, cell bodies and non-myelinated neurons.
what is is in the middle of the spinal cord
central canal
what is the central canal made of
cerebro-spinal fluid
where do the sensory neurone enter the spina cord
on the dorsal side through the dorsal root ganglion
where are the cell bodies of the sensory neurone found
dorsal root ganglion
where are the motor neurons found
in the ventral root, in the grey matter
what are Sensory and motor neurons are connected by
relay neurons in the grey matter
future sof a reflex arc
fast, automatic response to a stimulus that has a protective function
what is different In simple organisms such as Hydra and other cnidarians,
-respond limitedly to stimuli
-small number of effectors
-consists of a nerve net
what is different about nerve nets
-they are unmyelinated
-responses are slow
- degree of response is dependent on the strength of the stimulus and how many receptors are stimulated.
what type of neurones do humans have
sensory, relay and motor.
where do impulses enter the neurones
through small extensions of cytoplasm called dentrites
