Nervous system

Question 1

Cell body/soma

Answer 1

contains the nucleus, E.R., and ribosomes

Question 2

dendrites

Answer 2

receive incoming messages

Question 3

axon hillock

Answer 3

integrates the incoming signals from other cells to determine if an action potential will be produced; if sum of signals is excitatory above a threshold, action potential produced

Question 4

oligodendrocytes

Answer 4

produce myelin in the CNS

Question 5

Schawann cells

Answer 5

produce myelin in the peripheral nervous system

Question 6

Glial cells

Answer 6

have structural and supportive roles in the nervous system; 4 types: astrocytes, ependymal cells, microglia, oligodendrocytes/Schwann cells

Question 7

astrocytes

Answer 7

nourish neurons, form blood-brain barrier, which controls the solutes that can enter into the brain

Question 8

ependymal cells

Answer 8

line ventricles of the brain and produce cerebrospinal fluid, which supports the brain and absorbs shock

Question 9

microglia

Answer 9

phagocytes that break down waste and pathogens in the CNS

Question 10

Resting potential

Answer 10

about -70 mV, electric potential difference; selective permeability of ions (membrane more permeable to K ions, which diffuse out) and Na/K ATPase maintain negative resting potential

Question 11

hyperpolarization

Answer 11

lowers membrane potential to make neuron less likely to fire

Question 12

Summation

Answer 12

additive effect of multiple neurons acting on the same receiving neuron, combining excitatory signals to make it more likely to fire

Question 13

temporal summation

Answer 13

multiple signals are integrated in relatively short period of time

Question 14

spatial summation

Answer 14

effects based on the number and location of incoming signals

Question 15

refractory period

Answer 15

as a result of hyperpolarization following an action potential

Question 16

absolute refractory period

Answer 16

no amount of stimulation can cause another action potential to occur

Question 17

relative refractory period

Answer 17

there must be greater than normal stimulation to cause an action potential, as a result of the increased negative voltage with hyperpolarization

Question 18

impulse propagation

Answer 18

action potential travels down the axon by causing depolarization in each sequential segment of the axon, and then stimulates NT release from terminal buttons

Question 19

Speed of action potential propagation down axon

Answer 19

increased length- higher resistance, slower conduction
greater cross section area- faster propagation, less resistance
Myelin increases speed

Question 20

saltatory conduction

Answer 20

due to insulation of myelin, membrane only permeable to ions at nodes of Ranvier; signal hops from node to node

Question 21

Effector

Answer 21

postsynaptic cell that is a gland or a muscle rather than a neuron

Question 22

Release of NTs

Answer 22

stored in vesicles in nerve terminal; when action potential reaches terminal, Calcium channels open and Ca2+ flows into cell- triggers fusion of vesicle with membrane and exocytosis of NT

Question 23

Reuptake carriers

Answer 23

bring NTs from synapse back into presynaptic neuron

Question 24

white matter

Answer 24

consists of axons encased in myelin sheaths

Question 25

grey matter

Answer 25

consists of unmyelinated cell bodies and dendrites

Question 26

dorsal root ganglion

Answer 26

sensory neurons bring info in through the DRG to CNS

Question 27

peripheral nervous system

Answer 27

includes all 31 pairs of spinal nerves and 10 pairs of the cranial nerves, consists of somatic and autonomic nervous systems

Question 28

somatic nervous system

Answer 28

consists of sensory and motor neurons within the skin, joints, muscles

Question 29

parasympathetic nervous system

Answer 29

role is to conserve energy, associated with resting; reduces heart rate, constricts bronchi; increases digestion by increasing peristalsis

Question 30

somatic nervous system

Answer 30

increases heart rate, increases blood glucose, redistributes blood to muscles needed for movement, decreased digestion, decreased peristalsis, releases epinephrine, dilates pupils to let in more light

Question 31

Reflexes

Answer 31

interneurons in spinal cord send out quick response in certain situations because it would take too much time to get a response from the brain

Question 32

Monosynaptic reflex arc

Answer 32

single synapse between the sensory neuron that receives stimulus and motor neuron; ex. knee-jerk reflex

Question 33

Polysynaptic reflex arc

Answer 33

at least one interneuron between sensory and motor neurons; ex. withdrawal reflex (stepping on a nail)