Myology

Question 1

what are the functions of the muscular system

Answer 1

locomotion
vasoconstriction and vasodilation
peristalsis
cardiac motion
posture maintenance
heat generation
stabilize joints

Question 2

vasoconstriction and vasodilation

Answer 2

constriction and dilation of blood vessel walls are the results of smooth muscle contraction

Question 3

peristalsis

Answer 3

wavelike motion along digestive tract produced by the smooth muscle

Question 4

posture maintenance

Answer 4

contraction of skeletal muscles maintains the body posture and muscle tone

Question 5

heat generation

Answer 5

75% ATP energy used in muscle contraction is released as heat

Question 6

stabilise joints

Answer 6

even as they pull on bones to cause movement they strengthen and stabilise the joints of the skeleton

Question 7

properties of skeletal, cardiac and smooth muscles

Answer 7

striation
nucleus
transverse tubule
intercalated disk
control

Question 8

striation

Answer 8

only present in skeletal and cardiac uscles
absent in smooth

Question 9

nucleus

Answer 9

smooth and cardia are uni-nucleated
skeletal are multi-nucleated

Question 10

transverse tubule

Answer 10

well developed in skeletal and cardiac muscles to transport calcium
absent in smooth muscle

Question 11

intercalated disk

Answer 11

specialised intercellular junction that only occurs in cardiac muscle

Question 12

control

Answer 12

skeletal muscle is always under voluntary control
some exceptions such as tongue and pili arrector
smooth and cardiac are under involuntary control

Question 13

describe skeletal muscle

Answer 13

Question 14

describe cardiac muscle

Answer 14

Question 15

describe smooth muscle

Answer 15

Question 16

components of muscles

Answer 16

epimysium
muscle fascicle
muscle fibre
myofibrils
sarcolemma
sarcoplasm
sarcoplasmic reticuluum

Question 17

epimysium

Answer 17

outer layer of connective tissue covering an entire muscle

Question 18

muscle fascicle

Answer 18

bundle fo skeletal muscle fibres surrounded by perimysium

Question 19

muscle fibre

Answer 19

surrounded by a thin layer of connective tissue the endomysium
contains several hundred to thousand myofibrils

Question 20

myofibrils

Answer 20

composed of myofilaments (actin and myosin)

Question 21

sarcolemma

Answer 21

thin membrane enclosing skeletal muscle fibre

Question 22

sarcoplasm

Answer 22

intracellular fluid between myofibrils

Question 23

sarcoplasmic reticulum

Answer 23

specialised endoplasmic reticulum of skeletal muscle

Question 24

what is the triad and what is it composed of

Answer 24

each t tubule runs between pair of sacs formed by sarcoplasmic reticulum fusion
terminal cistern

can act as conduit for action potentials but no direct connection

Question 25

myofibril structure

Answer 25

composed of actin and myosin
light bands are only actin, I bands, isotropic to polarised light
dark bands are myosin filaments and ends of actin filaments, A bands, anisotropic to polarised light

Question 26

2 different bands

Answer 26

I and A
which are light and dark respectively

Question 27

light bands

Answer 27

I bands
only actin filaments
isotropic to polarised light

Question 28

dark bands

Answer 28

A bands
myosin filaments and ends of actin filaments
anisotropic to polarised light

Question 29

what is a Z disk

Answer 29

filamentous protein

Question 30

segment of myofibril between 2 successive Z disks is called what

Answer 30

sarcomere

Question 31

what is Titin

Answer 31

filamentous molecule to keep myosin and actin filaments in place

Question 32

what is a myofibril comprised of

Answer 32

actin and myosin

Question 33

what is an actin filament composed of

Answer 33

actin
troponin
tropomyosin

Question 34

structure of an actin filament

Answer 34

backbone of actin is double stranded F-actin protein
2 strands wound in helix
each strand of F is composed of G actin molecules
one ADP attached per one G-actin
ADP believed to be active sites
bases of actin filaments inserted into the Z disks

Question 35

label the image

Answer 35

Question 36

tropomyosin

Answer 36

another protein component of actin filament
wrapped spirally around sides of F-actin
lies on active sites of actin strands

Question 37

what does troponin have

Answer 37

3 subunits
T,I and C

Question 38

troponin T

Answer 38

strong affinity for tropomyosin

Question 39

troponin I

Answer 39

strong affinity for actin (inhibition)

Question 40

troponin C

Answer 40

strong affinity for calcium ion

Question 41

myosin structure

Answer 41

2 heavy chains and 4 light chains
2 heay wrap around to form double helix, called tail
end of each is folded bilaterally into globular polypeptide called myosin head
light chains help function during muscle contraction

Question 42

label the image

Answer 42

Question 43

2 main types of synapses

Answer 43

chemical
electrical

Question 44

chemical synapses

Answer 44

synaptic cleft
neurotransmitters
skeletal muscles

Question 45

electrical synapses

Answer 45

gap junction
cardiac ventricular muscle in the uterus and in the bladder

Question 46

which type of synapse is this

Answer 46

chemical

Question 47

which type of synapse is this

Answer 47

electrical

Question 47

which type of synapse is this

Answer 47

electrical

Question 48

nerve excitation process

Answer 48

Action potentials are propagated down the motoneuron
Calcium entry into the presynaptic terminus
Release of Ach from synaptic vesicles, diffusion across synaptic cleft and binding with post-synaptic receptors
ACh diffuses across the synaptic cleft to the postsynaptic membrane. This specialized region of the muscle fibre is called the motor end plate, which contains nicotinic receptors for ACh
Opening of Na+ /K+ channels on post-synaptic membrane
Postsynaptic membrane depolarization (End Plate Potential)
Ach breakdown via acetyl cholinesterase

Question 49

label the image of the synthesis and degradation of acetylcholine

Answer 49