Brainscape's Knowledge GenomeTM

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


See full index

HUBS191 > Muscles 1 > Flashcards

Muscles 1 Flashcards

1
Q

3 muscle types and briefly what they do:

A

Smooth muscles: mainly line hollow organs (gut, blood vessels) and are not under voluntary control

Cardiac muscles: located only in the heart, generates force to pup blood around the body and is not under voluntary control

Skeletal muscles: apply a force to the bones to control posture and body movements. Is under voluntary control. Striated/striped.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Primary Job of skeletal muscles

A

To develop tension or force
- muscles develop force in only one direction and they do this by shortening

(Skeletal muscle is important for movement and posture)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Secondary jobs of skeletal tissue

A
  • support and protection for soft internal organs (e.g muscles of abdominal wall)
  • provides voluntary control over major openings (allows the passage of substances into or out of our body)
  • converts energy (in part) to heat which is used to maintain core temperature (eg shivering)
  • provides major storage for energy and protein

SPCP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Structural features

A

-skeletal muscle fibres are huge and multinucleate cells containing large amounts of protein
- connective tissues ensheath the muscle, and connect fibres to the bones
- skeletal muscle is richly supplied with blood vessels and nerve fibres

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Whole muscle structure

A
  • muscle fibres are gathered into bundles called fascicles
  • fasicles are gathered into bundles called muscles
  • fibres, fascicles and muscles are each ensheathed in connective tissue
  • connective tissue investments are gathered together to form tendons
  • tendons connect muscles to bones
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

How various cells are arranged to form skeletal muscles

A
  • muscles are attached to bone via tendon
  • muscles are comprised of muscle tissue, nerves, blood vessels and connective tissue
  • each muscle is made of multiple muscle fibres
  • each muscle fibre is made of multiple myofibrils
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Endomysium

A

Surround each muscle fibre

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Perimysium

A

Surround each fascicle (bundle of muscle fibres)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Epimysium

A

Surround entire muscle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Surround each muscle fibre

A

Endomysium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Surround each facicle

A

Perimysium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Surround entire muscle

A

Epimysium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How many nuclei in a muscle fibre

A

Hundreds to thousands - on the outside

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

How big are muscle fibres

A

20-40 micrometers in diameter but may be centimetres long

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Key structural composition of a muscle fibre

A
  • comprised of bundles of myofibrils
  • myofibrils are made of repeating units known as sarcomeres
  • sarcomeres are made of contractile proteins or myofilaments (actin - thin filament, myosin - thick filament)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Two mayofilaments

A
  • actin (thin filaments)
  • myosin (thick filaments)
17
Q

What gives muscle its striated (striped) appearance

A

The organisation of the myofilaments

18
Q

Describe the purpose of the system of structures muscle fibres posses and some of these structures

A
  • Muscle fibres possess a system of structures organised to regulate the activity of the force-producing elements
  • Transverse tubules
    SR
19
Q

Two myofilaments are:

A
  • actin (thin filaments)
  • myosin (thick filaments)
20
Q

Definition of transverse tubules (T-tubules) and their function

A

Tubular extention (invaginations) of the surface membrane

Function: to conduct electrical signals (action potentials) deep into the core of the fibre

21
Q

Sacroplasmic reticulum (SR) definition

A

SR is an extensive membranous tubular network associated precisely with the T tubules at regular intervals.

22
Q

How the membrane triplet (triad) is formed

A

The terminal chambers (terminal cisternae) of each SR structure associate with the T-tubules to form a membrane triplet called a triad

23
Q

Function of the sacroplasmic Reticulum

A
  • to take up and store calcium
  • to release Ca2+ into the cytoplasm on the receipt of an action potential conducted along the associated T-tubules
24
Q

The sacromeric structure of the myofilaments arise do to:

A

The arrangement if contractile proteins
- thick filaments (primarily myosin) interlace with thin filaments (primarily actin)

25
Q

Actin definition

A

Actin is a globular protein

26
Q

Structure of Thin filament

A
  • Actin is a globular protein (G-actin)
  • The globules assemble to form filamentous protien strands (F - actin)
  • each thin filament is a twisted strand of 2 rows of F- actin terminating at one end of the Z-line
27
Q

Structure of the myosin molecule

A

Long thin tail and globular head

28
Q

Structure of the thick filament

A

(Myosin)

  • the thick filament is formed from arrays of pairs of myosin molecules arranged with the tails pointing towards the M-line and forming a complex double headed structure
  • the myosin heads are able to flex
29
Q

Sacroplasmioc reticulum DEFINITION

A

Is a mesh network that is interconnected and wraps around each myofibril - functions as a Ca2+ store

30
Q

Triad

A

Terminal cissternae of the SR and the t - tubes

31
Q

The sacromere contains:

A

Thick and thin myofilaments - contractile proteins

32
Q

The sliding filament theory

A
  • Contractile proteins develop force
    by triggered molecular interaction.
  • This allows association of the myosin head
    with the nearby thin actin filament.
  • Due to this it allows the flexing of the myosin
    head to allow it to “walk” along the thin
    filament
  • in this process the interlaces thick and thin filaments slide past one another
  • The arrangement of the myosin heads in a sarcomere means that when this process is activated, the ends of the sacromere are drawn closer together by the flexing of the myosin heads
  • the sacromere Z- lines are drawn closer to the central M-line
33
Q

Definition of Neuromuscular Junction

A

The myelinated axon of a motor neuron that terminates at a single point on the muscle fibre

  • each muscle fibre receives contact from one motor neuron at one site
34
Q

How electrical events in the brain initiate force production in the muscle:

A
  • muscle contractions are triggered by electrical events (AP)
  • AP’s arise in brain, are conducted down spinal cord to motor neurons in spinal cord
  • APS in spinal cord motor neurons are conducted out of CNS along motor axons to muscle fibres
  • arrival of AP at NMJ initiates SYNAPTIC TRANSMISSION which results in generation of AP in postscynaptic muscle fibre
  • AP in muscle fibre triggers a process (excitation-contraction coupling) that results in development of force within the fibre
35
Q

What does acetylcholine do

A

Acts at receptors on the muscle fibres membrane surface
- is a neurotransmitter

HUBS191 (36 decks)

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