Nervous System Flashcards Preview

SAT II BIOLOGY > Nervous System > Flashcards

Flashcards in Nervous System Deck (34):
1

Central Nervous System

Brain and Spinal Cord

Processes and stores infromation

2

Peripheral Nervous System

  • All nerves outside the CNS
  • Sensory, Motor
  • Somatic System, Autonomic System
  • Sympathetic, Parasympathetic

3

Sensory Nerves

Conveys info from sensory receptors or nerve endings

4

Motor Nerves

Stimulates voluntary and involuntary muscles 

Somatic /Autonomic  Systems

5

Somatic System

  • Controls the voluntary muscles
  • MOtor neurons relase acetylcholine onto ACh receptors located on skeletal muscle
  • Reflex action

6

Autonomic System

Controls involuntary muscles(glands and smooth muscles)

Sympathetic/Parasympathetic

7

Sympathetic

  • Norepinephrine as primary neurotransmitter
  • activates body for emergency situations
  • Fight or flight response
  • Increases heart and breathing rate
  • Liver converts glycogen to glucose
  • Bronchi of lungs dilate and icnrease gas exchange
  • Adrenaline raises blood glucose levels

8

Parasympathetic

  • Acetylcholine as primary neurotransmitter
  • rest-and-digest response
  • deactivate or slow down 
  • vagus nerve is principle nerve
  • Opposes the sympathetic system
  • Calms the body
  • Decreases heart/breathing rate
  • Enhances digestion'

9

Neuron

  • Nerve Cell
  • designed to transmit info in the form of electrochemical signals(action potentials)
  • COmposed of Dendrites, axons, cell body, myelin Sheaths

A image thumb
10

Dendrites

  • Receive incoming messages from other cells as changes in membrane potential 
  • carry the electrical signal to the cell body

11

Axon

  • Only one for each neuron
  • Transmits an impulse from the cell body to another cell
  • wrapped in a myelin sheet that protects the axon and speeds the impulse 

12

Reflex Arc

  • Simplest nerve response
  • Inborn, automatic, protective
  • ex/knee-jerk reflex
  • Spinal cord is not involved
  • Sensory, interneuron, motor neuron, muscle

13

Membrane Potential

  • A difference in electrical charge between the cytoplasm(negative charge) and extracellular fluid (positive)
  • difference between -50mV to -100mV

14

Polarized

  • A polarized neuron is at rest or unstimulated (resting potential)
  • membrane potential of -70mV
  • Sodium-potassium pump acitively pumps ions out of the cell 
  • The larger the membrane potential, the stronger the stimulus must be to cause the nerve to fire
  • Pos outside(sodium) ; neg inside(potassium)

15

Action potential

  • An impulse that can only be generated in the axon stimulated enough to overcome the threshold
  • Sodium channels open and sodium flood into the cell
  • Potassium channels open and potassium floods out of the cell
  • Polarity of the membrane is reversed (pos inside; neg outside)
  • Every action potential is the same size, but more frequency indiactes a larger stimulus

16

Wave of depolarization

  • Rapid movement ions when an impulse passes through an axon
  • Sodium in; potassium out
  • reverses the polarity of the membrane
  • Membrane is less polarized, moving toward 0 potential

17

Repolarization

Sodium-potassium pump restores the membrane to its orginal polarized condition 

18

Refractory Period

  • Period of repolarization
  • Neuron can't respond to another stimulus
  • ensures an impulse moves along an axon in 1 direction since the impulse can only move to a region where the membrane is polarized

19

Myelin Sheet

Protects axon and speeds impulse

20

What gives neurons an excitable membrane?

A voltage-gated sodium channel

21

Threshold Potential

  • The voltage at which the voltage-gated channels open

22

THe larger the neuron....

The faster action potentials travel

23

Nodes of Ranvier

Spaces between the myelin sheets that action potentials jumps from to another, bypassing myelin regions

24

Saltatory conduction

Action potentials jumping from Nodes of Ranvier to other nodes

25

Synapse/ Synaptic cleft

  • Gap between neuron and target cell where neurotranmitters cross

26

Neurotranmitter

  • chemical signal 
  • Released by neuron when an action potential travels down an axon to reach the synaptic terminal
  • diffuses across the gap between cells and bind to receptors on the target cell membrane

27

Summation

  • the means that a single neuron uses to process info from all neurons that form synapses with it and decide whether or not to initiate an action potential itself. 
  • determined by adding up the contributions to the membrane potential created by many synapses

28

Neuromuscular junction

  • A specialized synapse of motor neurons with skeletal muscle cells
  • When reached by action potential, acetylcholien is released into the synaptic cleft and binds to postsynaptic receptors in the muscle cell
  • receptors open sodium channels, depolrize msucle cell membrane, trigger muscle contraction

29

Ways to turn off a synaptic neurotransmitter

  1. Diffusion
  2. Enzymes that degrade and inactive it (pesticides, nerve gas)
  3. Take it up into cells at the synapse

30

Vesicles

The cytoplams at the terminal branch contains many vesicles, each containing neurotransmitters

31

What does deploarization of the presynaptic membrane cause?

  • Ca++ ions rush into terminal branch
  • stimulates the vesicles to fuse with the presynaptic membrane and release the neurotransmitter by exocytosis into the synapse
  • sets up another action potential on teh adjacent cell

32

Eye

A image thumb
33

Ear

A image thumb
34

Brain