lecture 20

Question 1

the three basic functions of the nervous system

Answer 1

sensory input
integration
motor output

Question 2

describe the three basic functions of the nervous system

Answer 2

o Sensory input – when the senses in the body are sent to the brain. When the body is in pain a pain signal is sent to the brain
- Comes from the sensor receptors in the eyes
o Integration – this is when the brain takes the sensory input, and it receives the information to then interpret it and decide on what to do with the information
o Motor output – this is where the integration of the sensory input is then put into some kind of action.

Question 3

central nervous system

Answer 3

CNS - the brain and spinal cord
- works to integrate and act as a control system for the body

Question 4

peripheral nervous system

Answer 4

(PNS) - the nerves and ganglia outside of the CNA
- all of the nerves and collections of bodies/substances outside of the CNS

Question 5

The PNS functional divisions

Answer 5

Afferent (sensory) division
Efferent (motor) division

Question 6

afferent division

Answer 6

the sensory division, is like the sensory signal we feel if we were to touch the flame of a candle. This sensory signal is then sent to the CNS.

Question 7

efferent division

Answer 7

the motor division, when a signal is sent from the CNS out to the body to create a movement or do something specific.

Question 8

the somatic nervous system

Answer 8

• Somatic nervous system: signals to the skeletal muscles, is voluntary
  o Example is picking up a pencil. This is efferent and somatic.

Question 9

autonomic nervous system

Answer 9

• Autonomic nervous system: signals to cardiac muscle, smooth muscle, or glands; is voluntary
  - these things the nervous system does automatically for us

Question 10

neuron

Answer 10

a cell that generates action potentials and sends them to other cells

Question 11

Neuroglia (glial cells)

Answer 11

generally work to support the neurons, are much smaller

Question 12

o Identify which parts of a neuron receive information, which part integrates information, and which part conducts the output signal

Answer 12

 Axon hillock -> is where the action potential begins. This is the region that tapers out almost like a hill and is where the signals are integrated.
 Axolemma -> is known as the plasma membrane of the axon
 Terminal branches -> where each branch of the cell can communicate with a cell
 Axon terminals -> these are the ends of the axon where the neurotransmitters are

Question 13

cell body of the neuron

Answer 13

is the control center region where most of the organelles are

Question 14

dendrite of the neuron

Answer 14

the shorter branching projections that come off the body
* There can be hundreds of dendrites coming off each body

Question 15

axon of the neuron

Answer 15

typically larger than the dendrite. There is only one per cell and it travels to communicate with other cells. Is a very long structure.
* An axon can travel all the way from the toe and up to the spinal cord or the brain. The axon sends signals away from the neuron.

Question 16

astrocyte

Answer 16

is a classification of a neuron in the CNS
named for their shape, have a star shape. Most abundant of all the glial cells.
* They help support and anchor the neurons, help with exchange between neurons and capillaries (exchange of nutrients and wastes), help to clean up leaked ions, might be helping the neurons to process information
- most abundant and versatile

Question 17

microglial cells

Answer 17

is a classification of a neuron in the CNS
- Help to monitor the health of neurons. If there is damage, they can migrate to the site of injury and transform into macrophages to help clean up the area.

Question 18

ependymal cells

Answer 18

is a classification of a neuron in the CNS
- line up together to form a sheet, they have cilia. Looks almost like epithelial tissue cells.
* Their job is to produce and circulate cerebral spinal fluid. The cilia waves around which help to circulate this.

Question 19

oligodendrocyte

Answer 19

a classification of a neuron in the CNS
have branches that come off and wrap around the nerve fibers in the CNS (wrap around the axons).
* What produces the myelin sheath in the CNS.

Question 20

satellite cells

Answer 20

a classification a a neuron in the PNS
surround the neurons cell bodies
* Like astrocytes but are outside of the CNS.
- look like satellites

Question 21

schwann cells

Answer 21

this is a type of classification of neuron in the PNS
are responsible for forming the myelin sheath in the PNS

Question 22

describe the function and composition of the myelin sheath

Answer 22

 Not all axons have one, but if it does have one, we can call it myelinated.
 Formed by the plasma membrane of the glial cells wrapping around the plasma membrane.
* Protects and electrically insulates the axons (helps with signal transmission). The myelin sheath speeds up the nerve impulse transmission.
o With the sheath signals travel hundreds of times faster.
 The Schwann cell will wrap around the axon many times allowing for protection

Question 22

what do oligodendrocytes do for the myelin sheath

Answer 22

they can wrap around multiple axons (one can wrap around up to 60 at one time)

Question 22

what are nodes of Ranvier

Answer 22

these are the gaps between the Schwann cells that are found.
* These are very important and about a millimeter apart all the way down the axon. It allows the signal to jump from one node to the next, which is referred to as saltatory conduction.

Question 23

what is white matter

Answer 23

these are areas of primarily myelinated fibers
* The more superficial part of the spinal cord.

Question 24

what is gray matter

Answer 24

these are areas with little myelination
* The areas that are deeper in the spinal cord and brain. Typically cell bodies or un myelinated axons.

Question 25

what is hydrocephalus

Answer 25

• is a condition where there is too much cerebrospinal fluid (CSF) in the brain
  
  • The ependymal cells are most affected by this

Question 26

multipolar neuron

Answer 26

• over 99% of neurons are this
  
  • this is where there are more than 3 projections. has one axon and the rest of the dendrites

Question 27

bipolar neuron

Answer 27

• is when you have two main projections coming off of the body. the axon and dendrites extend from opposite sides

Question 28

unipolar neuron

Answer 28

• is when there is only one projection off of the body. It often looks like a T.
  
  • the sensory in the PNS is this

Question 29

sensory (afferent) neurons function

Answer 29

• these send sensory signals from the body to the brain
  
  • transmit impulses from the sensory receptors in the skin toward or into the CNS

Question 30

motor (efferent) neurons function

Answer 30

• these carry motor signals away from the CNS, specifically to a effector organ

Question 31

interneurons function

Answer 31

• most of the CNS, more than 90% of neurons
  
  • they integrate signals from the sensory neurons and determine if it should be sent to the motor neurons

Question 32

what do motor neurons connect to

Answer 32

motor neurons connect to interneurons

Question 33

what are the somatic and autonomic nervous systems often referred to as

Answer 33

somatic - voluntary nervous system
autonomic - involuntary nervous system