Skeletal muscle anatomy Flashcards
(69 cards)
1
Q
Fascia
A
- tough connective tissue layer that encloses muscle fibres within a fascicle
2
Q
Fascicles
A
- bundle of muscle fibres enclosed by fascia within a skeletal muscle
- surrounded by connective tissue layer (perimysium)
3
Q
Muscle fibres
A
- within fascia
- surrounded by connective tissue layer (endomysium)
- contains sarcoplasm (cell cytoplasm)
4
Q
Sarcolemma
A
- muscle fibre plasma membrane
5
Q
Sarcoplasm
A
- muscle fibre cytoplasm
6
Q
A
7
Q
Mitochondria characteristic in a muscle fibre
A
- muscle cell contains many mitochondria
8
Q
Sarcoplasmic reticulum
A
Releases & stores Ca2+
9
Q
Transverse tubules
A
10
Q
Myofibrils
A
- responsible for muscle contraction
- made up of 3 kinds of protein; contractile, regulatory, & structural
11
Q
Myofilaments
A
- protein that makes up myofibrils
- arranged in sarcomeres
12
Q
Sarcomere
A
- contains actin & myosin (contraction)
- arranged along myofibril bordered by z-lines
- tiny units inside muscle fibers that make muscle contract
13
Q
Three types of muscle tissue
A
- skeletal
- cardiac
- smooth
14
Q
Why does a muscle fibre need multiple nuclei
A
- too big for one nucleus
- each nucleus controls specific region
- function; protein synthesis, repair
15
Q
How do muscle fibers become long?
A
myoblasts fuse together into one long cell during embryonic development
16
Q
When do muscle fibers become elongated?
A
During embryonic development
17
Q
The 3 proteins that make up myofibril
A
- Contractile - generate contraction force (pulls), (actin & myosin)
- Regulatory - start & stop (controls) contraction (troponin & tropomyosin)
- Structural - contractile protein alignment & stability (Z-Line, M-Line & Titan filament)
18
Q
Why is protein arrangement important in myofibril
A
- allows actin & myosin interact efficiently
- sarcomere pattern makes muscle strong
- without layout contraction = weak
19
Q
What creates muscle contraction?
A
- actin & myosin (proteins inside sarcomere) sliding past each other
- nerve signal; calcium release; actin unlocked; myosin pulls with ATP = contraction
20
Q
Myo, mys, sarco refer to
A
muscle
21
Q
A
22
Q
Myofibrils extend the
A
entire length of cell
23
Q
Z line
A
where actin filaments are anchored
24
Q
M line
A
where myosin filaments are anchored
25
I band
contains only actin filaments
26
A band
length of myosin filament
27
H zone
contains only myosin filaments
28
MHAZI
M line is inside the H zone, inside the A band, while the Z line is inside the I band
29
Myofilament arrangement is responsible for
branded/striated appearance of skeletal muscle
30
Thick filaments
- long, rope-like
- main protein: myosin
- myosin - tail; heavy polypeptide chain
- myosin - head; lighter polypeptide chain
31
Thin filaments
- twisted strands, double helix
- main proteins: actin, tropomyosin, troponin
- actin; polymer of globular subunits with attachment sites
- tropomyosin & troponin; regulatory subunits bound to actin
32
four factors that determine type of movement accompanied by a muscle
1. orientation of the muscle
2. action of other muscles
3. type of joint
4. muscle tension
33
Orientation of the muscle
- origin (anchor) & insertion (movement)
- muscle anchored to bone & movement of insertion determines movement
34
How action of other muscles determine movement
- muscles work together, one contracts (agonist) & other relaxes to allow movement (antagonist)
35
responsible for action while antagonist stretches & yields
agonist
36
order of organization in muscle tissue
filament, myofibril, muscle fiber, fascicle
37
thin & thick filaments are organized into functional units called
sarcomeres
38
cell membrane of muscle fibre
sarcolemma
39
rectus abdomen's
rectus; "erect", straight
abdominus; abdomen
40
direction of muscle fibers
rectus - straight, parallel to midlinewha
41
gluteus maximus
gluteus; location, butt
maximus; size (largest)
42
Deltoid
shape; triangular
43
abduction
movement away from midline
44
adduction
movement toward midline
45
circumduction
distal end of bone moves in circles
46
flexion
decrease joint angle
47
extension
increases joint angle
48
rotation
movement around longitudinal axis
49
supination
palm of hand turns upward
50
pronation
palm of hand turns downward
51
eversion
foot moves away from midline
52
inversion
foot moves toward midline
53
plantar flexion
foot extends at ankle
54
dorsiflexion
foot flexes at ankle
55
protraction
bone moves horizontally towards the front
56
retractions
bone moves horizontally towards the back
57
elevation
bone moves upward
58
depression
bone moves downward
59
ligaments
- fibrous connective tissue, attaches bone to bone
60
Tendon
- attaches muscle to bone
61
myofilament ____ filament
thin
62
myosin ____ filament
thick
63
anchors actin myofilaments in sarcomere
Z-line
64
Thick & thin filaments are organized into functional units called
sarcomeres
65
the cell membrane of a muscle fibre is called
sarcolemma
66
which motion moves the bottom of the foot away from the midline of the body
eversion
67
movement at the shoulder joint that moves the upper limb laterally away from the body is called
abduction
68
the angle between bones is decreased during
flexion
69
which term describes the muscle that moves the leg away from the body
abduction
