Cell physiology - part 2

Question 1

excitation (ions)

Answer 1

increase Na+ and Ca+

Question 2

inhibition (ions)

Answer 2

increase K+ and Cl-

Question 3

excited area

Answer 3

depolarised

more positive inside

Question 4

resting area

Answer 4

polarised

more negative inside

Question 5

saltatory conduction

Answer 5

impulses jump Schwann cells from node to node of Ranvier, faster

Question 6

what are nerves made up of

Answer 6

neuroglia/ glia
epineurium
perineurium
endoneurium

Question 7

neuroglia/ glia

Answer 7

non-neural cells maintain homeostasis by forming myelin (insulate, supply O2, hold neuron in place)

Question 8

epineurium

Answer 8

dense sheath of connective tissue covers each nerve

Question 9

perineurium

Answer 9

layer surrounds bundles of axons

Question 10

endoneurium

Answer 10

cover surrounding each fibre

Question 11

EPSP

Answer 11

excitatory post synaptic potential
depolarisation
glutamate, acetylcholine
Na+ in, K+ out

Question 12

IPSP

Answer 12

inhibitory post synaptic potential
hyperpolarisation
GABA, glycine
Cl- or K+ in

Question 13

summation

Answer 13

combination of EPSP and IPSP

Question 14

EPSP-IPSP cancellation

Answer 14

cancel each other out

Question 15

EPSP spatial summation

Answer 15

EPSP from different neurons trigger threshold point

Question 16

EPSP temporal summation

Answer 16

two EPSP from same neuron trigger threshold point

Question 17

composite post synaptic potential

Answer 17

all EPSPs and IPSP occur at the same time

Question 18

3 types of muscle

Answer 18

cardiac muscle
smooth muscle
skeletal muscle

Question 19

cardiac muscle

Answer 19

branched, unaligned fibres
gaps between allow for contraction
gap junction - exchange of small molecules
desmosomes (anchoring junction) - mechanical strength, keratin

Question 20

smooth muscle

Answer 20

spindle shaped, non-striated

Question 21

types of skeletal muscle

Answer 21

red muscle
white muscle
mixed muscle

Question 22

skeletal muscle

Answer 22

myofibrils (contractile fibres) are striated, aligned

Question 23

red muscle

Answer 23

skeletal muscle
highly vascular, many mitochondria and myoglobin
aerobic
slow contractility

Question 24

white muscle

Answer 24

skeletal muscle
not very vascular, not many mitochonria and myoglobin
anaerobic
faster contractility

Question 25

titin filaments

Answer 25

elastic protein chain keep filaments aligned

Question 26

syncytium

Answer 26

multicellular cell from fusion of many unicellular cells 
structtural syncytium - skeletal muscle
function syncytium - cardiac and smooth muscle

Question 27

phases of muscle contraction

Answer 27

contraction is depolarisation
excitation stimulates Na+ open 
Ca2+ open, Ca2+ in 
Ca2+ induce receptors on sarcoplasmic reticulum (SR) to secrete more Ca2+ (positive feedback)
Ca2+ stimulate contractile apparatus

Question 28

phases of muscle relaxation

Answer 28

relaxation is repolarisation
Ca2+ reuptake into sarcoplasmic reticulum (SR)
Na+/ Ca2+ exchanger (NCX): 2Na+ in, 1Ca2+ out
Na+/ K+ ATPase: 3Na+ out, 2K+ in
activation of K+ channels

Question 29

control of muscles

Answer 29

Ca2+ homeostasis from internal stores in sarcoplasmic reticulum (SR)

Question 30

latent period

Answer 30

time between stimulus and contraction

Question 31

excitation of muscles

Answer 31

twitch - single muscle contraction
wave summation - muscle does not completely relax between successive stimulations
incomplete tetanus - partial relaxation between increased frequency of stimulations
complete tetanus - no relaxation, complete contraction, maximal contraction