nervous system

Question 1

neurons

Answer 1

nerve cells that conduct signals, nucleated body, dendrites= nerves receptive apparatus, axon= long+carries away impulses, myelin= fatty sheath covered axon

Question 2

central nervous system

Answer 2

brain + nerve cord= interneurons conduct impulses= 99% of all neurons

Question 3

peripheral nervous system

Answer 3

afferent and efferent

Question 4

afferent (sensory) neurons

Answer 4

conduct sensory info from body to CNS

Question 5

efferent (motor) neurons

Answer 5

conduct motor info from CNS to the body

Question 6

nerves

Answer 6

collections of axon bound together by connective tissue

Question 7

ganglia

Answer 7

collections of neuronal cell bodies lying in the PNS

Question 8

neuroglia

Answer 8

(glial=glue) non-nervous cell support neurons (keep glued together)

Question 9

Schwann cells

Answer 9

forms myelin in the PNS

Question 10

oligodendrocytes

Answer 10

forms the myelin in the CNS

Question 11

nerve action potential

Answer 11

all nerve signals use electro-chemical message, relies on ion exchange across neuron membrane alter change inside cell

Question 12

action potential

Answer 12

all or none phenom- either conducting signal or not

Question 13

membrane potential

Answer 13

difference in electrical charge between inside/outside cell at rest neuron= more (-) than fluid

Question 14

sodium-potassium pump

Answer 14

moves sodium and potassium in opp. directions against its concentration gradient (channels specific to either)
voltage gated= open v. closed depends on membrane potential

Question 15

depolarization (rising phase)

Answer 15

Changes in membrane potential causes voltage-gated Na+ channels to open.
Na+ rush into the axon from the outside.
Interior becomes slightly positive with respect to exterior, membrane is depolarized.

Question 16

repolarization

Answer 16

Na+ gates close.
K+ gates open and K+ ions move out.
Reestablishes the resting membrane potential.
Interior once again negative with respect to the exterior.
A new action potential cannot occur because the sodium is inside and the potassium is outside.
Sodium-potassium pump re-establishes the resting potential

Question 17

synapse

Answer 17

Junction between two neurons or a neuron and an effector (muscle or gland).
An action potential passing down an axon must cross a small gap, the synapse

Question 18

presynaptic knobs release neurotransmitters.

Answer 18

One of the most common is acetylcholine

Question 19

Neurotransmitters

Answer 19

Diffuse across the gap in a fraction of a millisecond.
Bind to receptor molecules on ion channels in the postsynaptic membrane.
Causes a voltage change in the postsynaptic membrane.

Question 20

conduction and myelination

Answer 20

Nodes of Ranvier are exposed areas of the axon between adjacent regions of myelin.
Myelin insulation prevents depolarization, which, therefore, only occurs at the nodes.
Increases the speed of conduction.

Question 21

saltatory conduction

Answer 21

describes jumping behavior of the action potential which leaps from node to node.

Question 22

bilateral nervous system

Answer 22

sponges lack nerves or true neural cell types
cnidaria have a nerve net
flatworms= simplest system

Question 23

nervous system of arthropods

Answer 23

annelids= advanced to segments ganglia ganglia are larger, better developed sense organs

Question 24

encephalization

Answer 24

Increase and elaboration in size of the brain.
The brain and spinal cord compose the central nervous system.

Question 25

divisions of the vertebrate

Answer 25

forebrain (cerebrum +)- voluntary movement-touch smell
Midbrain- information processing- vision hearing
Hindbrain (Cerebellum +)- involuntary- HR, balance

Question 26

cerebral cortex

Answer 26

is site of “higher” mental activities. Largest of vertebrates

Question 27

corpus callosum

Answer 27

neural connection bridging the right and left hemispheres.
left- language, math, learning
right- spatial, musical, intuition

Question 28

somatic nervous sytem

Answer 28

division of efferent division, conducts motor messages to skeletal muscles

Question 29

autonomic nervous sytem

Answer 29

division of efferent system, controls involuntary internal functions, smooth muscle

Question 30

sympathetic nervous system

Answer 30

division of autonomic nervous system, active under conditions of physical stress or maintaining homeostasis

Question 31

parasympathetic

Answer 31

mostly active during rest periods

Question 32

sense organs

Answer 32

afferent system, stimuli come as energy (electrical, mechanical, chemical, radiant)

Question 33

exteroceptors

Answer 33

are located near the external body surface

Question 34

proprioceptors

Answer 34

in muscles, tendons, and joints, detect changes in tension =

Question 35

interoceptors

Answer 35

in internal organs

Question 36

chemoreceptors

Answer 36

smell (olfaction) and taste

Question 37

mechanoreceptors

Answer 37

touch, pressure, stretching, sound, vibrations, gravity, motion

Question 38

photoreceptors

Answer 38

vision