Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

1020 Human Physiology > Module 5 - Muscles > Flashcards

Module 5 - Muscles Flashcards

1
Q

fasciculi

A
  • Whole muscle is composed of bundles of fasciculi
  • Fascicles are composed of groups of muscle fibers
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

myofibrils

A
  • Each muscle cell contains many bundles
  • Each myofibril contains thick & thin myofilaments
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

arrangement of myofibrils

A
  • Thick & thin myofilaments are arranged end to end on the muscle
  • Alternate in repeating pattern along length of myofibril
  • Groups of thin extend outwards in opposite direction of Z disk
  • Groups of thick extend outwards from central M line
  • Parallel to length of myofibril & muscle cell
  • Thick filaments (dark bands) thin filaments (light bands)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

sarcomere

A
  • Smallest contractile unit of muscle cell
  • Shortens during muscle contraction
  • Region from one Z-band(disk) to another
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

thin myofilament

A
  • Predominately composed of protein actin
  • Contains tropomyosin & troponin
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

actin

A
  • protein
  • contains myosin binding site
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

tropomyosin

A
  • Long protein strands that wrap around actin proteins
  • In relaxed muscle, tropomyosin covers myosin binding sites on actin
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Troponin A

A
  • binds to actin
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Troponin C

A
  • binds to calcium
  • When Ca++ binds to troponin C, tropomyosin is pulled off binding sites by troponin
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Troponin T

A
  • binds to tropomyosin
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

troponin

A
  • Regulatory protein
  • Holds tropomyosin over myosin binding site
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

thick myofilaments

A
  • Composed of protein myosin
  • Heads attach to myosin binding site on actin
  • Many myosin molecules arranged to make one thick filament
  • Heads can bind & split ATP
  • Splitting of ATP releases energy to myosin to power muscle contraction
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

interaction of thick/thin myofilaments

A
  • Interaction between thick & thin leads to muscle contraction
  • Binding of myosin head to myosin binding site on actin forms crossbridge
  • Thick & thin filaments do not shorten during muscle contraction
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

exciting/contracting muscles

A
  • Process of action potential in cell membrane (sarcolemma)
  • Excites muscle cell to produce contraction
    1. Action potential (generated at NMJ) will spread over sarcolemma & down T-tubules into muscle cell
    2. Action potential travels very close to sarcoplasmic reticulum & opens Ca++ voltage-gated channels, causing release of Ca++ from terminal cisternae
    3. Ca++ will bind to troponin C on thin filament, causing tropomyosin to uncover myosin bonding sites
    4. Myosin will now be able to attach to actin & powerstroke will occur
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

events of muscle contraction

A
  1. Action potential travels close to sarcoplasmic reticulum (SR) & opens Ca++ voltage-gated channels, Ca++ is release from terminal cisternae of SR
  2. Ca++ will bind to troponin C on thin filament causing tropomyosin to uncover myosin binding sites
  3. Formation of crossbridge when Ca++ binds to troponin C will roll tropomyosin off binding sites on actin
  4. Myosin is now able to attach to actin
  5. Powerstroke will occur when myosin head bends thin myofilaments of actin over thick myofilaments
  6. Powerstroke causes ATP to release from myosin head, split into ADP & Pi, the split releases energy & cocks myosin head to bind to actin of open myosin binding sites
  7. New ATP binds to myosin head, crossbridge is broken & cycle repeats
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

functions of ATP in muscle contraction

A
  • Positions myosin head & increases myosin strength to bind to the site on actin
  • Energizes myosin to power crossbridge movement (powerstroke)
  • Releases myosin from actin
  • Pumps Ca++ back into sarcoplasmic reticulum SR (active process)
17
Q

rigor mortis

A
  • Loss of ATP in dead muscle cells (no ATP production)
  • Post mortem rigidity & stiffness of muscles
  • Slow decomposition of sarcoplasmic reticulum (SR) release Ca++
  • Myosin bonds to actin creating crossbridge
  • Without ATP bonds cannot be broken, producing rigiol conditions
18
Q

motor unit

A
  • Consists of motor neuron & all muscle cells that contract
  • One motor neuron will contact several muscle cells
  • Muscle cells are innervated by only one motor neuron
  • Large motor units, motor neuron in contact with large number of muscle cells
  • Small motor units, motor neuron in contact with small number of muscle cells
19
Q

grading of muscle contraction

A
  • Recruitment of motor units, more units recruited, more muscle cells activated/contracting increasing overall force of contraction
  • Summation of twitch contraction, increase force by increasing frequency of action potentials, each twitch has less time to relax, producing summation of twitch contraction

1020 Human Physiology (16 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions