Unit 2

Question 1

what are the three main functions of the nervous system

Answer 1

receives info - use receptors to receive from internal or external environment, integrate info - organize bring together with already stored info, traduces info, send signal to muscle or glands

Question 2

what are the two main components of the nervous system

Answer 2

Central Nervous System, Peripheral Nervous System

Question 3

what is the CNS made up of and what are the two important terms

Answer 3

brain, spinal cord and is associated with nuclei and tracts

Question 4

what is nuclei

Answer 4

clusters of cell bodies

Question 5

what is tracts

Answer 5

bundles of axons forming a pathway

Question 6

what is the PNS made of?

Answer 6

nerves, receptors, peripheral nerves, ganglia - cluster of cell bodies

Question 7

the entire nervous system can be broken down into these components

Answer 7

receptors, afferent neurons, interneurons, efferent neurons

Question 8

what are receptors

Answer 8

specialized cells, convert stimuli into electrical signals, transmit info to afferent neurons

Question 9

what is afferent neurons

Answer 9

receive info from receptor cells, transmit sensory info to CNS, cell bodies located outside CNS, transmit info to interneurons within CNS

Question 10

what are interneurons

Answer 10

located inside CNS, make up 96% of neurons, transmit info within CNS, laterally within spinal cord or vertically to brain, integrate info from afferent neurons to efferent neurons

Question 11

what are efferent neurons

Answer 11

receive info from interneurons, cell bodies located within CNS, carry out message, are muscles, glands

Question 12

what are the two basic kinds of cells within the nervous system

Answer 12

neurons, glial cells

Question 13

what are the four main parts of neurons

Answer 13

soma (cell body), dendrites, axon, axon terminals

Question 14

what are soma

Answer 14

contain nucleus sand biosynthetic machinery, center of chemical process keep cell functioning and alive

Question 15

what are dendrites

Answer 15

slender process that receive info, transmit electrical signals as graded potentials towards soma

Question 16

what is axon

Answer 16

cytoplasmic extensions and send out info, transmit electrical signal away from soma

Question 17

what is axon terminals

Answer 17

end of axon, connection between neuron and other ells, participate as part of synapse - presynaptic, postsynaptic and synaptic cleft

Question 18

what are the diverse neuron forms and functions?

Answer 18

pseudounipolar, bipolar, anoxic, multipolar- CNS, multipolar - efferent

Question 19

what is pseudounipolar

Answer 19

somatic sensory neurons, one long process

Question 20

what is bipolar

Answer 20

smell and vision sensory neurons, contain single axon and dendrite

Question 21

what is anaxonic?

Answer 21

interneuron, no apparent axon

Question 22

what is multipolar - CNS

Answer 22

highly branched no long extension

Question 23

what is multipolar efferent

Answer 23

contain 5-7 dendrites, single long axon

Question 24

how do glial cells communicate with each other and nearby neurons

Answer 24

using electrical and chemical signals

Question 25

how do glial cells contribute to function of neurons in two main ways

Answer 25

aid in nerve impulse conduction, maintain microenvironment around neurons

Question 26

how much do glial cells outnumber neurons? 50 by?

Answer 26

50:1

Question 27

what are the PNS Glial cells?

Answer 27

schwann cells, and satellite cells

Question 28

in PNS Glial cells, what are schwann cells?

Answer 28

special glial cells wrapped around axons

Question 29

what is myelin

Answer 29

layers of membrane

Question 30

what is found between layers of myelin sheath?

Answer 30

gap junctions

Question 31

when myelin acts as electrical insulator, what do they do?

Answer 31

reduce leakage of ions across cell membrane of the neuron

Question 32

in PNS Glial cells, what is satellite cells?

Answer 32

non-myelinating schwann cells, support nerve cell bodies (soma)

Question 33

what are the CNS Glial Cells?

Answer 33

oligodendria, astroglia, microglia, epemdumal cells

Question 34

what are oligodendria?

Answer 34

CNS version of the Schwann cell, wrap around axon and insulate axons

Question 35

what are astroglia

Answer 35

star shaped cells, contact blood vessels and neurons, transfer nutrietns, maintain neuron microenvironment, maintain homeostasis in extracellular fluid

Question 36

what is microglia

Answer 36

small cells, specialized immune cells, function to remove damaged cells and foreign invaders

Question 37

what are ependymal cells

Answer 37

epithelial cells produce cerebral spinal fluid, selectively permeable barrier between compartments of the brain

Question 38

how do neurons transmit electrical impulses

Answer 38

using action potential

Question 39

opposite charges attract

Answer 39

likes repel

Question 40

electrical force decrease as

Answer 40

distance between charges increase

Question 41

electrical force increase as

Answer 41

number of charges increase

Question 42

what is the difference in charge between inside and outside of cell called

Answer 42

electrical gradient

Question 43

how does osmotic pressure occur

Answer 43

difference in concentration across membranes - the concentration gradient

Question 44

what are the components of cell membranes

Answer 44

semi-permeable, impermeable to most molecules except hydrophobic molecules e.g. steroid hormones - estrogen, testosterone, cortisol

Question 45

how do most molecules move across cell membrane

Answer 45

channels, pores, or assisted by protein pumps

Question 46

what does no concentration gradient/no electrical gradient = OR concentration gradient exactly balances

Answer 46

no net movement

Question 47

what does the nernst equation calculate

Answer 47

any given ion you can calculate electrical potential of the cell to generate equilibrium state, if you know the concentration gradient

Question 48

the inside of a cell is electronegative and is usually between -70 to

Answer 48

-90 mV for neurons

Question 49

where do ions with positive equilibrium potential move

Answer 49

into a resting cell

Question 50

where do ions with negative equilibrium move

Answer 50

out of resting cell

Question 51

charge difference between inside and outside of cell at rest called

Answer 51

resting membrane potential

Question 52

why is it called resting membrane potential

Answer 52

resting - membrane potential at steady state membrane potential - electrical and chemical gradients caused by distribution of ions across cell membrane source o stored potential energy

Question 53

what sets resting membrane potentail

Answer 53

concentration of each of the ions and relative permeability

Question 54

what is higher in ECF and higher in ICF

Answer 54

Na+, Cl-, Ca2+ higher in ECF K+ higher in ICF

Question 55

membrane permeability can be mathematically expressed using

Answer 55

Goldman-Hodgkin-Katz (GHK) equation

Question 56

what is the GHK equation

Answer 56

takes into account membrane permeability of each ion

Question 57

why doesnt K+ keep leaking out of cell, until they reach equilibrium potentials

Answer 57

they do leak out but Na+/K+ ATPase offset the leak

Question 58

what are the three different gated channels

Answer 58

mechanically-gated, voltage-gated, chemically gated

Question 59

what are mechanically-gated

Answer 59

channels found in sensory neurons, open in response to physical forces

Question 60

what is voltage-gated

Answer 60

initiation and conduction of electrical signals, respond to change in voltage

Question 61

what is chemically gated

Answer 61

respond to ligands such as neurotransmitters, neuromodulators or intracellular signal molecules

Question 62

what are the four types of selective ion channels in neuron

Answer 62

Na+ channels, K+ channels, Ca2+ channels, Cl- channels

Question 63

why have we spent so much time on the resting potential

Answer 63

neurons use stored energy in electrical and chemical gradients to transmit electrical signals

Question 64

what are the two main concepts of transmission of electrical signals

Answer 64

depolarization, and hyperpolarization

Question 65

what is depolarization

Answer 65

decrease in membrane potential differnce, cell membrane potential become less negative

Question 66

what is hyper polarization

Answer 66

increase in membrane potential difference, cell membrane potential becomes more negative

Question 67

how do cells change their membrane potential

Answer 67

change the membrane ion permeability, don with protein channels in membrane

Question 68

how do cells change permeability?

Answer 68

change total number of protein channels, open or close existing protein channels

Question 70

what is Na+ critical for

Answer 70

generate changes in membrane potential cause electrical signals

Question 70

what are long distance signal called

Answer 70

action potentials

Question 71

what are short distance signals called

Answer 71

graded potentials

Question 72

Na+ contribute minimally to resting membrane potential

Answer 72

due to low permeability

Question 73

where do graded potentials occur

Answer 73

in dendrites or cell body of neurons

Question 74

what is graded potential triggered by

Answer 74

opening or closing of ion channels

Question 75

why are they called graded

Answer 75

because of amplitude of potential is proportional to strength of the triggering event

Question 76

what causes graded potential to lose strength

Answer 76

current leak - some positive charge leak back with depolarization wave, cytoplasmic resistance - cytoplasm restricts flow of the current

Question 77

what causes ions to enter the cell

Answer 77

initialized by neurotransmitters binding to membrane receptors and opening ion channels

Question 78

what are the events that occur after neurotransmitter binding

Answer 78

ion channels open, ions move into Na+ or out of K+ the neuron along their electrochemical gradient, wave of depolarization or hyperpolariztion spread through the cell

Question 79

what is signal strength

Answer 79

determined by number of ions entering cell, graded potential diminish strengths distance increases