lecture 8 & 9 muscle system

Question 1

what is muscle organ made of

Answer 1

keletal muscle fibres( muscle cells), connective tissue that harness forces of contraction, blood vessels and nerves.

Question 2

whats the resting membrane potential

Answer 2

-70mV

Question 3

define depolarisation

Answer 3

when a chemical stimulus opens the Na+ ion protein channels, so Na+ moves into cell, making the membrane potential less -ve

Question 4

define repolarisation

Answer 4

when the Na+ protein channels pump Na+ out of the cell lowering the resting potential back to -70mV

Question 5

Define hyperpolarisation

Answer 5

When the protein channels for K+ open up, due to a chemical stimuli, causing the K+ to leave the cell, making the membrane potential more negative

Question 6

whats more highly charged the ECM or cytosol

Answer 6

the ECM

Question 7

difference between sarcolemma and endomysium

Answer 7

The sarcolemma is the cell membrane of the muscle fiber, and the endomysium is the connective tissue layer over the muscle fiber.

Question 8

roles of muscle main and the secondary roles

Answer 8

Primary job is to produce tension force by contraction of the muscle.
secondary
Muscle supports and protects soft internal organs
Provides voluntary control over openings allowing passage for substances into the body.
Also converts energy into heat which is used to maintain homeostasis, and thermoregulation.
Provides a store for energy and protein

Question 9

what gives muscle its striated appearance

Answer 9

the organisation of the thick and thin myofilaments

Question 10

describe thin filament structure

Answer 10

globular protein, globules assemble to make protein strands, each thin filament is a twisted strand of two of these protein strands.

Question 11

describe thick filament structure

Answer 11

myosin, has long thin tale with myosin heads. arrays of pairs of myosin molecules with tails going toward m line and forming complex double headed structure

Question 12

what are muscle contractions triggered by

Answer 12

action potentials

Question 13

describe the path an action potential takes

Answer 13

Brain>Spinal cord>motor neuron> axon of neuron> muscle fibre> sarcolemma>t tubules> Sarcoplasmic reticulum.

Question 14

Arrival of an action potential at the
neuromuscular junction initiates
what? generating an
what

Answer 14

synaptic transmission, generating an
action potential in the muscle fibre

Question 15

what causes the Myosin head to cock forward

Answer 15

the hydrolysis of ATP to ADP + pi

Question 16

myosin + actin is called

Answer 16

a cross bridge

Question 17

what does the myosin head bind to

Answer 17

the actin binding site

Question 18

what in myosin hydrolyses the ATP to ADP + pi

Answer 18

Myosin ATPase

Question 19

what is osmolarity

Answer 19

the total number of solute particles per litre of solution. an absolute value

Question 20

what is tonicity

Answer 20

the ability of a solution surrounding the cell to cause the cell to lose or gain water. a relative value

Question 21

name of the process that takes AP from Neuron to the Muscle fibre.

Answer 21

Synaptic transmission