Download The Nervous System * Crash Course Biology

The Nervous System – Crash Course Biology
The nervous system is up made of specialized cells, most of those are _______________.
Neurons bundle together to form ________________.
The nervous system is divided into two main departments the _______________________ nervous
system and the _____________________ nervous system.
The CNS contains the _________________ and the ____________________. It analyzses the data from
the _____________________________.
Afferent neurons carry information ____ the brain and efferent neurons carry information ______ from
the brain.
In the peripheral nervous system (the PNS), efferent neurons are mostly ____________ neurons
because they carry information to muscles and make you move.
The PNS is made up of the somatic nervous system and the autonomic nervous system.
The somatic system controls which one – things you think about or don’t think about?
Examples:
(True or False? All the incoming sensory information goes up to brain where we make decisions about
what to do.)
The autonomic system controls which one – things you think about or don’t think about?
Examples:
The autonomic nervous systems itself has two divisions that work in tandem:
The sympathetic system – does it excite you or calm you down? (circle one)
Examples:
The parasympathetic system – does it excite you or calm you down? (circle one)
Examples:
Neuron Anatomy – fill in the parts of the neuron below:
________________________ branches like a tree that receive info from other neurons
_______________________ the trunk of the tree that transmits info
________________________ a fatty substance that covers the axon
____________________________ breaks in the myelin sheath that lets the signal hop down the neuron
___________________________________ this means leaping, as in the info jumps from node to node
_______________________________ the space between neurons where neurotransmitter leaves the
terminal buttons of one cell and diffuses to the dendrites on the next neuron
The Action Potential
The sodium-potassium _____________ moves ions across the neurons membrane creating a net
negative? positive? (circle one) charge inside the cell.
The membrane also has proteins straddling it that do not need ATP to function and are called _____
channels.
When an action potential begins ______ channels open and ______ rushes in making it less negative
inside. With enough stimulus it reaches a threshold and more _______ channels respond and open and
let ____ ions in. This happens in one tiny area of the neuron but the change in voltage creeps over to the
next batch of Na+ (sodium) channels that then open and trigger the next batch to do the same.
Since most of the neuron is covered by the ___________________ sheath this event only happens at
the ________________ which produces the salutatory conduction as the change in voltage event leaps
down the axon.
When the wave reaches the end of the neuron it triggers the release of neurotransmitter through the
process of ________________________________. Those neurotransmitters flow across the
_________________ to the next neuron where they trigger another action potential over there.
Back to the resting potential
By this time so many sodium (Na+) ions have gotten inside the first neuron that the inside of the neuron
is now more __________________ then the outside. To fix this the ____________ channels close and
the __________________ channels open up and the ions move down both their ___________________
gradient and _______________________ gradient. But now the Na+ is on the ____________________
and the potassium is on the ____________________ of the cell so the Na+/K+ pump has to move them
back to the starting position.
The Nervous System – Crash Course Biology
ANSWERS
The nervous system is up made of specialized cells, most of those are __NEURONS__.
Neurons bundle together to form ___NERVES___.
The nervous system is divided into two main departments the _____CENTRAL_______ nervous system
and the ___PERIPHERAL___ nervous system.
The CNS contains the ___BRAIN____ and the ___SPINAL CORD___. It analyzses the data from the
______PERIPHERAL______.
Afferent neurons carry information _TO_ the brain and efferent neurons carry information _FROM__
from the brain.
In the peripheral nervous system (the PNS), efferent neurons are mostly _MOTOR__ neurons because
they carry information to muscles and make you move.
The PNS is made up of the somatic nervous system and the autonomic nervous system.
The somatic system controls which one – things you think about or don’t think about?
Examples: MOVEMENT, WALKING, PICKING STUFF UP
(True or False? All the incoming sensory information goes up to brain where we make decisions about
what to do.) FALSE
The autonomic system controls which one – things you think about or don’t think about?
Examples: BREATHING, HEART RATE, HORMONE RELEASE, SWEATING
The autonomic nervous systems itself has two divisions that work in tandem:
The sympathetic system – does it excite you or calm you down? (circle one)
Examples: INCREASE HR, DIVERT BLOOD TO PERIPHERY, DECREASE DIGESTION, DILATE
PUPILS
The parasympathetic system – does it excite you or calm you down? (circle one)
Examples: DECREASE HEART RATE, CONSTRICT PUPILS, DIVERT BLOOD AWAY FROM
PERIPHERY AND TOWARD DIGESTION,
Neuron Anatomy – fill in the parts of the neuron below:
______DENDRITES_____ branches like a tree that receive info from other neurons
_____AXON_______ the trunk of the tree that transmits info
__MYELIN SHEATH____ a fatty substance that covers the axon
__NODES OF RANVIER_ breaks in the myelin sheath that lets the signal hop down the neuron
___SALTATORY CONDUCTION__ this means leaping, as in the info jumps from node to node
__SYANPTIC GAP___ the space between neurons where neurotransmitter leaves the terminal buttons
of one cell and diffuses to the dendrites on the next neuron
The Action Potential
The sodium-potassium _PUMP___ moves ions across the neurons membrane creating a net negative?
positive? (circle one) charge inside the cell.
The membrane also has proteins straddling it that do not need ATP to function and are called _ION_
channels.
When an action potential begins _Na+ (sodium)__ channels open and _Na+__ rushes in making it less
negative inside. With enough stimulus it reaches a threshold and more _Na+_ channels respond and
open and let ____ ions in. This happens in one tiny area of the neuron but the change in voltage creeps
over to the next batch of Na+ (sodium) channels that then open and trigger the next batch to do the
same.
Since most of the neuron is covered by the _MYELIN__ sheath this event only happens at the _NODES
OF RANVIER_ which produces the salutatory conduction as the change in voltage event leaps down the
axon.
When the wave reaches the end of the neuron it triggers the release of neurotransmitter through the
process of ___EXOCYTOSIS___. Those neurotransmitters flow across the _SYANPTIC GAP__ to the next
neuron where they trigger another action potential over there.
Back to the resting potential
By this time so many sodium (Na+) ions have gotten inside the first neuron that the inside of the neuron
is now more __POSITIVE___ then the outside. To fix this the __Na+___ channels close and the _K+
(POTASSIUM)__ channels open up and the ions move down both their _CONCENTRATION__ gradient
and __ELECTRICAL___ gradient. But now the Na+ is on the INSIDE_ and the potassium is on the
__OUTSIDE_ of the cell so the Na+/K+ pump has to move them back to the starting position.