Muscle Tissue

Июль 22, 2022

Содержание

2. Muscle Tissue Muscles tissue distributed almost everywhere Some functions of muscular tissue Propels food we eat
3. Muscle Tissue Three types of muscle tissue: Skeletal muscle, cardiac muscle, smooth muscle Composes 40-50% of
4. 3 Types of Muscle Tissue Skeletal Smooth Cardiac
5. Introduction to Skeletal Muscle: Functions of Skeletal Muscle Functions of Skeletal Muscle Body movement Maintenance of
6. Introduction to Skeletal Muscle: Functions of Skeletal Muscle Body movement, maintenance of posture, protection and support,
7. Introduction to Skeletal Muscle: Characteristics Skeletal Muscle Tissue Characteristics Excitability responsive to nervous system stimulation neurons
8. Introduction to Skeletal Muscle: Characteristics Skeletal Muscle Tissue Characteristics (continued) Elasticity due to protein fibers acting
9. Anatomy of Skeletal Muscle: Gross Anatomy Skeletal muscle Composed of thousands of muscle cells Typically as
10. Skeletal Muscle High Magnification Nuclei A band I band
11. Anatomy of Skeletal Muscle: Gross Anatomy Connective tissue components Three concentric layers of connective tissue: epimysium,
12. Anatomy of Skeletal Muscle: Gross Anatomy Connective tissue components (continued) Epimysium layer of dense irregular connective
13. Connective Tissue and Fascicles Epimysium Perimysium Fascicle Endomysium Epimysium + Perimysium + Endomysium = Tendon
14. Anatomy of Skeletal Muscle: Gross Anatomy Connective tissue components (continued) Tendon cordlike structure composed of dense
15. Tendon and Aponeurosis of Palmaris Longus muscle
16. Anatomy of Skeletal Muscle: Gross Anatomy Connective tissue components (continued) Deep fascia additional sheet of dense
17. Superficial and Deep Fasciae 10- Superficial Deep
18. Anatomy of Skeletal Muscle: Gross Anatomy Connective tissue components (continued) Superficial fascia superficial to deep fascia
19. Skin
20. Superficial Fascia
21. Deep Fascia
22. Superficial Muscles
23. Deeper Muscles
24. Even Deeper Muscles
25. Yet Even Deeper Muscles
26. Soft Tissue and Bone
27. Bone
28. Anatomy of Skeletal Muscle: Gross Anatomy Blood vessels and nerves Skeletal muscles vascularized by extensive blood
29. Structural Organization of Skeletal Muscle (Figure 10.1) Copyright © The McGraw-Hill Companies, Inc. Permission required for
30. Anatomy of Skeletal Muscle: Gross Anatomy The endomysium is the layer of connective tissue surrounding the
31. Anatomy of Skeletal Muscle: Microscopic Anatomy Sarcoplasma Cytoplasm of muscle fibers (cells comprising muscle) Contains typical
32. Anatomy of Skeletal Muscle: Microscopic Anatomy Multinucleated cell Elongated cells extending length of muscle Myoblasts embryonic
33. Anatomy of Skeletal Muscle: Microscopic Anatomy Multinucleated cell (continued) Satellite cells myoblasts remaining, unfused, in adult
34. Anatomy of Skeletal Muscle: Microscopic Anatomy Sarcolemma and T-tubules Plasma membrane of a skeletal muscle fiber
35. Anatomy of Skeletal Muscle: Microscopic Anatomy Sarcolemma and T-tubules (continued) Na+/ K+ pumps along sarcolemma and
36. Anatomy of Skeletal Muscle: Microscopic Anatomy Sarcolemma and T-tubules (continued) Voltage-gated Na+ channels and voltage-gated K+
37. Anatomy of Skeletal Muscle: Microscopic Anatomy Sarcoplasmic reticulum Internal membrane complex Similar to smooth endoplasmic reticulum
38. Structure and Organization of a Skeletal Muscle Fiber: Sarcolemma and T-Tubules (Figure 10.3 b) Copyright ©
39. Sarcoplasmic reticulum (continued) Ca2+ pumps embedded in sarcoplasmic reticulum move Ca2+ into sarcoplasmic reticulum stored bound
40. Anatomy of Skeletal Muscle: Microscopic Anatomy Muscle fibers and myofibrils Myofibrils long cylindrical structures extend length
41. Structure and Organization of a Skeletal Muscle Fiber (Figure 10.3 a) Copyright © The McGraw-Hill Companies,
42. Anatomy of Skeletal Muscle: Microscopic Anatomy Muscle fibers and myofibrils (continued) Thick filaments Assembled from bundles
43. Anatomy of Skeletal Muscle: Microscopic Anatomy Muscle fibers and myofibrils (continued) Thin filaments Primarily composed of
44. Anatomy of Skeletal Muscle: Microscopic Anatomy Muscle fibers and myofibrils Thin filaments (continued) Tropomyosin twisted “stringlike”
45. Molecular Structure of Thick and Thin Filaments (Figure 10.4) Copyright © The McGraw-Hill Companies, Inc. Permission
46. Anatomy of Skeletal Muscle: Microscopic Anatomy Organization of a sarcomere Myofilaments arranged in repeating units, sarcomeres
47. Anatomy of Skeletal Muscle: Microscopic Anatomy Organization of a sarcomere Overlapping filaments (continued) Form alternating patterns
48. Skeletal Muscle (striations) Skeletal muscle fiber A band I band Nuclei
49. Sarcomere A band H band I band M line Myofibril Sarcomere Z disc
50. Structure of a Sarcomere (Figure 10.5 a) Copyright © The McGraw-Hill Companies, Inc. Permission required for
51. Anatomy of Skeletal Muscle: Microscopic Anatomy Organization of a sarcomere (continued) Overlapping filaments I bands region
52. Anatomy of Skeletal Muscle: Microscopic Anatomy Organization of a sarcomere Overlapping filaments (continued) A band central
53. Anatomy of Skeletal Muscle: Microscopic Anatomy Organization of a sarcomere Overlapping filaments (continued) H zone central
54. Structure of a Sarcomere (Figure 10.5 b) Copyright © The McGraw-Hill Companies, Inc. Permission required for
55. Structure of a Sarcomere (Figure 10.5 c) Copyright © The McGraw-Hill Companies, Inc. Permission required for
56. Anatomy of Skeletal Muscle: Microscopic Anatomy Organization of a sarcomere Other structural and functional proteins Connectin
57. Anatomy of Skeletal Muscle: Microscopic Anatomy Organization of a sarcomere Other structural and functional proteins (continued)
58. Anatomy of Skeletal Muscle: Microscopic Anatomy Mitochondria and other structures associated with energy production Muscle with
59. Anatomy of Skeletal Muscle: Microscopic Anatomy Mitochondria and other structures associated with energy production (continued) Myoglobin
60. Anatomy of Skeletal Muscle: Microscopic Anatomy Thick filaments are composed of myosin protein. What are the
61. Anatomy of Skeletal Muscle: Microscopic Anatomy H zone In which band are there thick filaments only,
62. Anatomy of Skeletal Muscle: Innervation of Skeletal Muscle Fibers Motor unit Motor neuron nerve cells transmit
63. Anatomy of Skeletal Muscle: Innervation of Skeletal Muscle Fibers Motor unit (continued) Varied number of fibers
64. Anatomy of Skeletal Muscle: Innervation of Skeletal Muscle Fibers Motor unit (continued) Fibers dispersed throughout most
65. Anatomy of Skeletal Muscle: Innervation of Skeletal Muscle Fibers Neuromuscular junctions Location where motor neuron innervates
66. Neuromuscular Junction High Magnification Skeletal muscle fiber Axon of motor nerve Motor end plate
67. Anatomy of Skeletal Muscle: Innervation of Skeletal Muscle Fibers Neuromuscular junctions (continued) Synaptic knob The expanded
68. Neuromuscular Junction TEM: High Magnification Primary synaptic cleft Synaptic vesicles of synaptic terminal Secondary synaptic cleft
69. Anatomy of Skeletal Muscle: Innervation of Skeletal Muscle Fibers Neuromuscular junctions Synaptic knob (continued) Has voltage-gated
70. Anatomy of Skeletal Muscle: Innervation of Skeletal Muscle Fibers Neuromuscular junctions Motor end plate Specialized region
71. Anatomy of Skeletal Muscle: Innervation of Skeletal Muscle Fibers Neuromuscular junctions (continued) Synaptic cleft Narrow fluid-filled
72. Structure and Organization of a Neuromuscular Junction (Figure 10.7a) Neuromuscular junction Nerve signal Synaptic cleft Endomysium
73. Structure and Organization of a Neuromuscular Junction (Figure 10.7b) K+ (b) Interstitial fluid Ca2+ pump Voltage-gated
74. Anatomy of Skeletal Muscle: Innervation of Skeletal Muscle Fibers A motor unit is a single motor
75. Physiology of Skeletal Muscle Contraction During muscle contraction Protein filaments within sarcomeres interact Sarcomeres shorten Tension
76. Overview of Events in Skeletal Muscle Contraction (Figure 10.8) 1 2 3 NEUROMUSCULAR JUNCTION: EXCITATION OF
77. Skeletal Muscle Contraction—Neuromuscular Junction: Excitation of a Skeletal Muscle Fiber First physiological event Muscular fiber excitation
78. Skeletal Muscle Contraction—Neuromuscular Junction: Excitation of a Skeletal Muscle Fiber Calcium entry at synaptic knob Nerve
79. Skeletal Muscle Contraction—Neuromuscular Junction: Excitation of a Skeletal Muscle Fiber Release of ACh from synaptic knob
80. Skeletal Muscle Contraction—Neuromuscular Junction: Excitation of a Skeletal Muscle Fiber Binding of ACh at motor end
81. Neuromuscular Junction: Excitation of a Skeletal Muscle Fiber (Figure 10.9) Motor end plate 1 NEUROMUSCULAR JUNCTION:
82. Skeletal Muscle Contraction—Neuromuscular Junction: Excitation of a Skeletal Muscle Fiber Nerve signal triggers the entry of
83. Skeletal Muscle Contraction—Neuromuscular Junction: Excitation of a Skeletal Muscle Fiber Clinical View: Myasthenia Gravis Autoimmune disease,
84. Skeletal Muscle Contraction—Sarcolemma, T-Tubules, Sarcoplasmic Reticulum: Excitation-Contraction Coupling Second physiological event Excitation-contraction coupling Links skeletal muscle
85. Skeletal Muscle Contraction—Sarcolemma, T-Tubules, Sarcoplasmic Reticulum: Excitation-Contraction Coupling Development of an end-plate potential at the motor
86. Skeletal Muscle Contraction—Sarcolemma, T-Tubules, Sarcoplasmic Reticulum: Excitation-Contraction Coupling Development of an end-plate potential at the motor
87. Skeletal Muscle Contraction—Sarcolemma, T-Tubules, Sarcoplasmic Reticulum: Excitation-Contraction Coupling Initiation and propagation of action potential along the
88. Skeletal Muscle Contraction—Sarcolemma, T-Tubules, Sarcoplasmic Reticulum: Excitation-Contraction Coupling Initiation and propagation of action potential along the
89. Skeletal Muscle Contraction—Sarcolemma, T-Tubules, Sarcoplasmic Reticulum: Excitation-Contraction Coupling Release of calcium from the sarcoplasmic reticulum Opening
90. Skeletal Muscle Fiber: Excitation-Contraction Coupling (Figure 10.10) Copyright © The McGraw-Hill Companies, Inc. Permission required for
92. Скачать презентацию

Слайд 2

Muscle Tissue
Muscles tissue distributed almost everywhere
Some functions of muscular tissue
Propels food

we eat along gastrointestinal tract
Expels waste we produce
Changes amount of air that enters the lung
Pumps the blood to body tissues

Слайд 3

Muscle Tissue
Three types of muscle tissue:
Skeletal muscle, cardiac muscle, smooth muscle
Composes

40-50% of weight of the adult
700 skeletal muscles in the muscular system

Слайд 4

3 Types of Muscle Tissue
Skeletal
Smooth
Cardiac

Слайд 5

Introduction to Skeletal Muscle: Functions of Skeletal Muscle
Functions of Skeletal Muscle

Body movement
Maintenance of posture
Protection and support
Storage and movement of materials
sphincters,
Heat production
shiver when cold to generate heat

Слайд 6

Introduction to Skeletal Muscle: Functions of Skeletal Muscle
Body movement, maintenance of

posture, protection and support, storage and movement of material, and heat production.

What are the five major functions of skeletal muscle?

Слайд 7

Introduction to Skeletal Muscle: Characteristics Skeletal Muscle Tissue
Characteristics
Excitability
responsive to nervous system

stimulation
neurons secreting neurotransmitters that bind to muscle cells
Conductivity
electrical change traveling along plasma membrane
initiated in response to neurotransmitter binding
Contractility
contractile proteins within muscle cells
slide past each other
tension used to pull on bones of skeleton

Слайд 8

Introduction to Skeletal Muscle: Characteristics Skeletal Muscle Tissue
Characteristics (continued)
Elasticity
due to protein

fibers acting like compressed coils
when contraction ended, tension in proteins released
muscle returns to original length
Extensibility
lengthening of a muscle cell
e.g., extension of the triceps brachii when flex elbow joint

Слайд 9

Anatomy of Skeletal Muscle: Gross Anatomy
Skeletal muscle
Composed of thousands of muscle

cells
Typically as long as the entire muscle
Often referred to as muscle fibers
Organized into bundles, termed fascicles
Muscle composed of fibers, connective tissue, blood vessels, nerves

Слайд 10

Skeletal Muscle High Magnification
Nuclei
A band
I band

Слайд 11

Anatomy of Skeletal Muscle: Gross Anatomy
Connective tissue components
Three concentric layers of

connective tissue:
epimysium, perimysium, endomysium
Provide
protection
sites for blood vessel and nerve distribution
means of attachment to skeleton or other structures

Слайд 12

Anatomy of Skeletal Muscle: Gross Anatomy
Connective tissue components (continued)
Epimysium
layer of dense

irregular connective tissue
surrounds whole skeletal muscle
Perimysium
dense irregular tissue surrounding the fascicles
contains extensive blood vessels and nerves supplying fibers
Endomysium
innermost connective tissue layer
delicate areolar connective tissue
surrounds and electrically insulates each muscle fiber
contains reticular protein fibers
help bind together neighboring muscle fibers

Слайд 13

Connective Tissue and Fascicles
Epimysium
Perimysium
Fascicle
Endomysium
Epimysium + Perimysium + Endomysium = Tendon

Слайд 14

Anatomy of Skeletal Muscle: Gross Anatomy
Connective tissue components (continued)
Tendon
cordlike structure composed

of dense regular connective tissue
formed by the three connective tissue layers
attach the muscle to bone, skin or another muscle
Aponeurosis
thin, flattened sheet of dense irregular tissue
formed from the three connective tissue layers

Слайд 15

Tendon and Aponeurosis of Palmaris Longus muscle

Слайд 16

Anatomy of Skeletal Muscle: Gross Anatomy
Connective tissue components (continued)
Deep fascia
additional sheet

of dense irregular connective tissue
external to the epimysium
separates individual muscles
binds together muscles with similar functions
contains nerves, blood vessels, and lymph vessels
fills spaces between muscles

Слайд 17

Superficial and Deep Fasciae
10-
Superficial
Deep

Слайд 18

Anatomy of Skeletal Muscle: Gross Anatomy
Connective tissue components (continued)
Superficial fascia
superficial to

deep fascia
composed of areolar and adipose connective tissue
separates muscles from skin

Слайд 19

Skin

Слайд 20

Superficial Fascia

Слайд 21

Deep Fascia

Слайд 22

Superficial Muscles

Слайд 23

Deeper Muscles

Слайд 24

Even Deeper Muscles

Слайд 25

Yet Even Deeper Muscles

Слайд 26

Soft Tissue and Bone

Слайд 27

Bone

Слайд 28

Anatomy of Skeletal Muscle: Gross Anatomy
Blood vessels and nerves
Skeletal muscles vascularized

by extensive blood vessels
Deliver oxygen and nutrients, removing waste products
Innervated by motor neurons
Axons
extend through connective layers
almost make contact with individual muscle fiber
junction termed the neuromuscular junction
Skeletal muscle termed voluntary muscle
because fibers consciously controlled by nervous system

Слайд 29

Structural Organization of Skeletal Muscle (Figure 10.1)
Copyright © The McGraw-Hill Companies, Inc.

Permission required for reproduction or display.

Epimysium

Tendon

Deep fascia

Skeletal muscle

Artery

Vein

Nerve

Perimysium

Fascicle

Endomysium

Muscle fiber

Слайд 30

Anatomy of Skeletal Muscle: Gross Anatomy
The endomysium is the layer of

connective tissue surrounding the whole skeletal muscle and providing protection.

What are the locations of the endomysium, perimysium, and epimysium?

The perimysium surrounds the muscle fascicles and contains extensive blood vessels and nerves.

The endomysium is the innermost layer surrounding and electrically insulating muscle fibers.

Слайд 31

Anatomy of Skeletal Muscle: Microscopic Anatomy
Sarcoplasma
Cytoplasm of muscle fibers (cells comprising

muscle)
Contains typical cellular structures
e.g., Golgi apparatus, ribosomes, vesicles
Has specialized cellular structure

Слайд 32

Anatomy of Skeletal Muscle: Microscopic Anatomy
Multinucleated cell
Elongated cells extending length of

muscle
Myoblasts
embryonic cells which fuse
form single skeletal muscle fibers during development
each contributing a nucleus to total nuclei
Thus fibers multinucleated cells

Слайд 33

Anatomy of Skeletal Muscle: Microscopic Anatomy
Multinucleated
cell (continued)
Satellite cells
myoblasts remaining, unfused, in

adult skeletal tissue
may be stimulated to differentiate if tissue injured
(Figure 10.2)

Muscle fiber

Myoblasts

Satellite cell

Nuclei

Muscle fiber

Myoblasts fuse
to form a skeletal
muscle fiber.

Слайд 34

Anatomy of Skeletal Muscle: Microscopic Anatomy
Sarcolemma and T-tubules
Plasma membrane of a

skeletal muscle fiber
sarcolemma
Invaginations of the sarcolemma
T-tubules, or transverse tubules

Слайд 35

Anatomy of Skeletal Muscle: Microscopic Anatomy
Sarcolemma and T-tubules (continued)
Na+/ K+ pumps

along sarcolemma and T-tubules
create concentration gradients for Na+ and K+
three Na+ pumped out while two K+ pumped in
resting membrane potential maintained by pumps
inside of cell relatively negative in comparison to outside
responsible for excitability of skeletal muscle fibers

Слайд 36

Anatomy of Skeletal Muscle: Microscopic Anatomy
Sarcolemma and T-tubules (continued)
Voltage-gated Na+ channels

and voltage-gated K+ channels
also present
necessary for propagation of electrical change along sarcolemma

Слайд 37

Anatomy of Skeletal Muscle: Microscopic Anatomy
Sarcoplasmic reticulum
Internal membrane complex
Similar to

smooth endoplasmic reticulum
Surround bundles of contractile proteins
Terminal cisternae
blind sacs of sarcoplasmic reticulum
serve as reservoirs for calcium ions
combine in twos with central T-tubule to form triads

Слайд 38

Structure and Organization of a Skeletal Muscle Fiber: Sarcolemma and T-Tubules

(Figure 10.3 b)

–

Interstitial fluid

Sarcoplasm

Sarcolemma

(b) Sarcolemma and T-tubules

T-tubule

3 Na+ out

Na+/K+
pump

Voltage-gated
Na+ channel

–

2K+ in

Voltage-gated
K+ channel

–

Na+

K+

–

Слайд 39

Sarcoplasmic reticulum (continued)
Ca2+ pumps embedded in sarcoplasmic reticulum
move Ca2+ into sarcoplasmic

reticulum
stored bound to specialized proteins, calmodulin and calsequestrin
Voltage-gated Ca2+ channels
open to release Ca2+ from sarcoplasmic reticulum into sarcoplasm
causes muscle contraction

(Figure 10.3c)

Ca2+ pump

Calsequestrin

Calmodulin

Terminal cisterna

Sarcoplasm

SR membrane

Ca2+

Voltage-gated
Ca2+ channel

Слайд 40

Anatomy of Skeletal Muscle: Microscopic Anatomy
Muscle fibers and myofibrils
Myofibrils
long cylindrical structures

extend length of muscle fiber
compose 80% of volume of muscle fiber
each fiber with hundreds to thousands
Myofilaments
bundles of protein filaments
takes many to extend length of myofibril
two types: thick and thin

Слайд 41

Structure and Organization of a Skeletal Muscle Fiber (Figure 10.3 a)
Copyright

Muscle

Fascicle

Muscle fiber

Sarcoplasmic
reticulum

Triad

Terminal
cisternae

T-tubule

Sarcolemma

Myofibrils

Sarcomere

Myofilaments

Nucleus

Openings into
T-tubules

(a) Skeletal muscle fiber

Nucleus

Sarcoplasm

Mitochondrion

Nucleus

Слайд 42

Anatomy of Skeletal Muscle: Microscopic Anatomy
Muscle fibers and myofibrils (continued)
Thick filaments

Assembled from bundles of protein molecules, myosin
each myosin protein with two intertwined strands
each strand with a globular head and elongated tail
tails pointing toward center of thick filaments
heads pointing toward edges of thick filaments
head with a binding site for actin (thin filaments)
head with site where ATP attaches and is split

Слайд 43

Anatomy of Skeletal Muscle: Microscopic Anatomy
Muscle fibers and myofibrils (continued)
Thin filaments
Primarily

composed of two strands of protein, actin
Two strands twisted around each other
Many small spherical molecules, globular actin
Connected to form a fibrous strand, filamentous actin
Globular actin with myosin binding site
where myosin head attaches during contraction

Слайд 44

Anatomy of Skeletal Muscle: Microscopic Anatomy
Muscle fibers and myofibrils
Thin filaments

(continued)
Tropomyosin
twisted “stringlike” protein
cover small bands of the actin strands
covers myosin binding sites in a noncontracting muscle
Troponin
globular protein attached to tropomyosin
binding site for Ca2+
together form troponin-tropomyosin complex

Слайд 45

Molecular Structure of Thick and Thin Filaments (Figure 10.4)
Copyright © The McGraw-Hill

Companies, Inc. Permission required for reproduction or display.

Myosin molecule

G-actin

Muscle fiber

Myofibril

Myofilaments

Heads

Actin binding site

ATP and ATPase binding site

Myosin heads

(a) Thick filament

(b) Thin filament

Tropomyosin

F-actin

Myosin binding site

Troponin

Ca2+ binding site

Tail

Слайд 46

Anatomy of Skeletal Muscle: Microscopic Anatomy
Organization of a sarcomere
Myofilaments arranged in

repeating units, sarcomeres
Number varies with length of myofibril
Composed of overlapping thick and thin filaments
Delineated at both ends by Z discs
specialized proteins perpendicular to myofilaments
anchors for thin filaments

Слайд 47

Anatomy of Skeletal Muscle: Microscopic Anatomy
Organization of a sarcomere
Overlapping filaments (continued)
Form

alternating patterns of light and dark regions
Appears striated under a microscope
due to size and density differences between thick and thin filaments
Each thin filament with three thick filaments
form triangle at its periphery

Слайд 48

Skeletal Muscle (striations)
Skeletal muscle fiber
A band
I band
Nuclei

Слайд 49

Sarcomere
A band
H band
I band
M line
Myofibril
Sarcomere
Z disc

Слайд 50

Structure of a Sarcomere (Figure 10.5 a)
Copyright © The McGraw-Hill Companies,

Inc. Permission required for reproduction or display.

Muscle fiber

(a)

Sarcomeres

Myofilaments

Myofibril

I band

A band

I band

Z disc

H zone

Z disc

M line

Sarcomere

Слайд 51

Anatomy of Skeletal Muscle: Microscopic Anatomy
Organization of a sarcomere (continued)
Overlapping filaments
I

bands
region containing only thin filaments
extend from both directions of Z disc
bisected by Z disc
appear light under a microscope
disappear at maximal muscle contraction

Слайд 52

Anatomy of Skeletal Muscle: Microscopic Anatomy
Organization of a sarcomere
Overlapping filaments (continued)
A

band
central region of sarcomere
contains entire thick filament
contains partially overlapping thin filaments
appears dark under a microscope

Слайд 53

Anatomy of Skeletal Muscle: Microscopic Anatomy
Organization of a sarcomere
Overlapping filaments (continued)
H

zone
central portion of A band
thick filaments only present; no thin filament overlap
disappears during maximal muscle contraction
M line
protein meshwork structure at center of H zone
attachment site for thick filaments

Слайд 54

Structure of a Sarcomere (Figure 10.5 b)
Copyright © The McGraw-Hill Companies,

Inc. Permission required for reproduction or display.

Connectin

Z disc

Thin filament

Thick filament

Sarcomere

Z disc

Thin filament

(b)

I band

A band

H zone

I band

M line

Слайд 55

Structure of a Sarcomere (Figure 10.5 c)
Copyright © The McGraw-Hill Companies,

Inc. Permission required for reproduction or display.

(c)

Z disc
Thin filaments
Connectin
and accessory
proteins

I band
Thin filaments
Connectin

A band
Thick filaments
Thin filaments

H zone
Thick filaments

M line
Thick filaments
and accessory
proteins

Transverse
sectional plane

Слайд 56

Anatomy of Skeletal Muscle: Microscopic Anatomy
Organization of a sarcomere
Other structural and

functional proteins
Connectin
protein extending from Z discs to M line
extends through core of each thick filament
stabilizes the position of thick filaments
springlike to produce passive tension during contraction
during relaxation, passive tension released

Слайд 57

Anatomy of Skeletal Muscle: Microscopic Anatomy
Organization of a sarcomere
Other structural and

functional proteins (continued)
Nebulin
actin-binding protein
part of I band of the sarcomere
plays possible role in creating orderly structure of sarcomere
Dystrophin
anchors myofibrils adjacent to sarcolemma to sarcolemma proteins
links internal myofilament proteins to external proteins
abnormal structure or amounts of proteins in muscular dystrophy

Слайд 58

Anatomy of Skeletal Muscle: Microscopic Anatomy
Mitochondria and other structures associated with

energy production
Muscle with high ATP requirement
Abundant mitochondria for aerobic cellular respiration
Glycogen stores for immediate fuel molecule
Creatinine phosphate
molecule unique to muscle tissue
provides fibers means of supplying ATP anaerobically

Слайд 59

Anatomy of Skeletal Muscle: Microscopic Anatomy
Mitochondria and other structures associated with

energy production (continued)
Myoglobin
molecule unique to muscle tissue
reddish globular protein similar to hemoglobin
binds oxygen when muscle at rest
releases it during muscular contraction
provides additional oxygen to enhance aerobic cellular respiration

Слайд 60

Anatomy of Skeletal Muscle: Microscopic Anatomy
Thick filaments are composed of myosin

protein.

What are the primary components of thick and thin filaments?

Thin filaments are composed primarily of actin protein. Tropomyosin and tropin are associated regulatory proteins.

Слайд 61

Anatomy of Skeletal Muscle: Microscopic Anatomy
H zone
In which band are there

thick filaments only, with no thin filament overlap?

Слайд 62

Anatomy of Skeletal Muscle: Innervation of Skeletal Muscle Fibers
Motor unit
Motor neuron

nerve cells
transmit nerve signals from brain or spinal cord
have axons that branch
individually innervate numerous skeletal muscle fibers
single motor neuron + fibers it controls = motor unit

Слайд 63

Anatomy of Skeletal Muscle: Innervation of Skeletal Muscle Fibers
Motor unit (continued)
Varied

number of fibers a neuron innervates
small motor units less than five muscle fibers
large motor units with several thousand
inverse relationship between size of motor unit and degree of control
e.g., small motor units innervating eye
need greater control
e.g., large motor units innervating lower limbs
need less precise control

Слайд 64

Anatomy of Skeletal Muscle: Innervation of Skeletal Muscle Fibers
Motor unit (continued)
Fibers

dispersed throughout most of a muscle
Stimulation producing weak contraction over a wide area

Слайд 65

Anatomy of Skeletal Muscle: Innervation of Skeletal Muscle Fibers
Neuromuscular junctions
Location where

motor neuron innervates muscle
Usually mid-region of muscle fiber
Has synaptic knob, motor end plate, synaptic cleft

Слайд 66

Neuromuscular Junction High Magnification
Skeletal muscle fiber
Axon of motor nerve
Motor end plate

Слайд 67

Anatomy of Skeletal Muscle: Innervation of Skeletal Muscle Fibers
Neuromuscular junctions (continued)
Synaptic

knob
The expanded tip of the axon
Axon enlarged and flattened in this region
Houses synaptic vesicles, small membrane sacs
filled with neurotransmitter, acetylcholine (ACh)
Has Ca2+ pumps embedded in plasma membrane
establish calcium gradient, with more outside the neuron

Слайд 68

Neuromuscular Junction TEM: High Magnification
Primary synaptic cleft
Synaptic vesicles of synaptic terminal
Secondary

synaptic cleft (junctional folds)

Mitochondria of synaptic terminal

Слайд 69

Anatomy of Skeletal Muscle: Innervation of Skeletal Muscle Fibers
Neuromuscular junctions
Synaptic knob

(continued)
Has voltage-gated Ca2+ channels in membrane
Ca2+ flowing down concentration gradient if opened
Vesicles normally repelled from membrane of synaptic knob
because both normally negatively charged

Слайд 70

Anatomy of Skeletal Muscle: Innervation of Skeletal Muscle Fibers
Neuromuscular junctions
Motor end

plate
Specialized region of sarcolemma
Has numerous folds
increase surface area covered by knob
Has vast numbers of ACh receptors
plasma membrane protein channels
opened by binding of ACh
allow Na+ entry and K+ exit

Слайд 71

Anatomy of Skeletal Muscle: Innervation of Skeletal Muscle Fibers
Neuromuscular junctions (continued)
Synaptic

cleft
Narrow fluid-filled space
Separates synaptic knob and motor end plate
Acetylcholinesterase residing here
enzyme that breaks down ACh molecules
after their release into synaptic cleft

Слайд 72

Structure and Organization of a Neuromuscular Junction (Figure 10.7a)
Neuromuscular
junction
Nerve signal
Synaptic
cleft
Endomysium
Sarcolemma
(a)
Synaptic knob
Myofibril
Myofilaments
Motor end
plate
Copyright

Слайд 73

Structure and Organization of a Neuromuscular Junction (Figure 10.7b)
K+
(b)
Interstitial fluid
Ca2+ pump
Voltage-gated
Ca2+ channels
Sarcolemma
Synaptic

knob

Sarcoplasm

Ach receptor

Junction fold

Motor end plate

–Na+

ACh

Vesicle
with ACh

Ca2+

Synaptic
cleft

Слайд 74

Anatomy of Skeletal Muscle: Innervation of Skeletal Muscle Fibers
A motor unit

is a single motor neuron and the muscle fibers it controls.

What is a motor unit, and why does it vary in size?

There is an inverse relationship between size and degree of control. Muscles needing greater power but less control have bigger motor units.

Слайд 75

Physiology of Skeletal Muscle Contraction
During muscle contraction
Protein filaments within sarcomeres interact
Sarcomeres

shorten
Tension is exerted on portion of skeleton where muscle attached
Contracting fiber decreases in length
Movement occurs

Слайд 76

Overview of Events in Skeletal Muscle Contraction (Figure 10.8)
1
2
3
NEUROMUSCULAR JUNCTION: EXCITATION

OF A SKELETAL MUSCLE FIBER

Release of neurotransmitter acetycholine (ACh) from synaptic vesicles and
subsequent binding of Ach to Ach receptors.

SARCOLEMMA, T-TUBULES, AND SARCOPLASMIC
RETICULUM: EXCITATION-CONTRACTION COUPLING

ACh binding triggers propagation of an action potential
along the sarcolemma and T-tubules to the sarcoplasmic
reticulum, which is stimulated to release Ca2+.

SARCOMERE: CROSSBRIDGE CYCLING

Ca2+ binding to troponin triggers sliding of thin
filaments past thick filaments of sarcomeres;
sarcomeres shorten, causing muscle contraction.

Ca2+

Sarcomere

Sarcolemma

Muscle
fiber

Neuromuscular
junction

Synaptic vesicle (contains ACh)

Action potential

T-tubule

ACh

Ach receptor

Sarcoplasmic
reticulum

Terminal
cisterna
of SR

Thick filament

Thin filament

Ca2+

Слайд 77

Skeletal Muscle Contraction—Neuromuscular Junction: Excitation of a Skeletal Muscle Fiber
First

physiological event
Muscular fiber excitation by motor neuron
Occurs at neuromuscular junction
Results in release of ACh and subsequent binding of ACh receptors

Слайд 78

Skeletal Muscle Contraction—Neuromuscular Junction: Excitation of a Skeletal Muscle Fiber
Calcium

entry at synaptic knob
Nerve signal propagated down motor axon
Triggers opening of voltage-gated Ca2+ channels
Movement of calcium down concentration gradient
from interstitial fluid into synaptic knob
Binding of calcium with proteins on synaptic vesicles

Слайд 79

Skeletal Muscle Contraction—Neuromuscular Junction: Excitation of a Skeletal Muscle Fiber
Release

of ACh from synaptic knob
Merging of synaptic vesicles with synaptic knob membrane
triggered by binding of Ca2+
Exocytosis of ACh into synaptic cleft
About 300 vesicles per nerve signal

Слайд 80

Skeletal Muscle Contraction—Neuromuscular Junction: Excitation of a Skeletal Muscle Fiber
Binding

of ACh at motor end plate
Diffusion of ACh across synaptic cleft
Binds with ACh receptors within motor end plate
Causes excitation of muscle fiber

Слайд 81

Neuromuscular Junction: Excitation of a Skeletal Muscle Fiber (Figure 10.9)
Motor end

plate

NEUROMUSCULAR JUNCTION: EXCITATION OF A SKELETAL MUSCLE FIBER

Ca2+ entry at synaptic knob

Nerve signal

ACh receptor

Synaptic cleft

Interstitial
fluid

Synaptic vesicles
(contain ACh)

A nerve signal is propagated down a motor axon and triggers
the entry of Ca2+ into the synaptic knob.

Ca2+ binds to proteins in synaptic vesicle membrane.

Release of ACh from synaptic knob

Binding of ACh to ACh receptor at motor end plate

ACh diffuses across the fluid-filled synaptic cleft in the
motor end plate to bind with ACh receptors.

Ca2+

ACh

Synaptic
vesicle

ACh

Voltage-gated
Ca2+ channel

Synaptic knob

Calcium binding triggers synaptic vesicles to merge
with the synaptic knob plasma membrane and ACh
is exocytosed into the synaptic cleft.

Слайд 82

Skeletal Muscle Contraction—Neuromuscular Junction: Excitation of a Skeletal Muscle Fiber
Nerve

signal triggers the entry of calcium into the synaptic knob. Calcium binding to synaptic vesicles triggers the exocytosis of ACh.

What triggers the binding of synaptic vesicles to the synaptic knob membrane to cause exocytosis of ACh?

Слайд 83

Skeletal Muscle Contraction—Neuromuscular Junction: Excitation of a Skeletal Muscle Fiber
Clinical

View: Myasthenia Gravis
Autoimmune disease, primarily in women
Antibodies binding ACh receptors in neuromuscular junctions
Receptors removed from muscle fiber by endocytosis
Results in decreased muscle stimulation
Rapid fatigue and muscle weakness
Eye and facial muscles often involved first
May be followed by swallowing problems, limb weakness

Слайд 84

Skeletal Muscle Contraction—Sarcolemma, T-Tubules, Sarcoplasmic Reticulum: Excitation-Contraction Coupling
Second physiological event
Excitation-contraction coupling
Links

skeletal muscle stimulation to events of contraction
Consists of three events:
development of end-plate potential at motor end plate
initiation and propagation of action potential along sarcolemma
release of Ca2+ from sarcoplasmic reticulum

Слайд 85

Skeletal Muscle Contraction—Sarcolemma, T-Tubules, Sarcoplasmic Reticulum: Excitation-Contraction Coupling
Development of an end-plate

potential at the motor end plate
Binding of ACh to ACh receptors on motor end plate
Receptors stimulated to open
Allows Na+ to rapidly diffuse into muscle fiber
Allows K+ to slowly diffuse out

Слайд 86

Skeletal Muscle Contraction—Sarcolemma, T-Tubules, Sarcoplasmic Reticulum: Excitation-Contraction Coupling
Development of an end-plate

potential at the motor end plate (continued)
Net gain of positive charge inside fiber
Reverses electrical charge difference at motor end plate
reverse termed an end plate potential (EPP)
transient, localized at motor end plate
Can be stimulated again almost immediately

Слайд 87

Skeletal Muscle Contraction—Sarcolemma, T-Tubules, Sarcoplasmic Reticulum: Excitation-Contraction Coupling
Initiation and propagation of

action potential along the sarcolemma and T-tubules
Action potential triggered by EPP
first, inside of sarcolemma becoming relatively positive
due to influx of Na+ from voltage-gated channels
termed depolarization
then, inside of sarcolemma returning to resting potential
due to outflux of K+ from voltage-gated channels
termed repolarization

Слайд 88

Skeletal Muscle Contraction—Sarcolemma, T-Tubules, Sarcoplasmic Reticulum: Excitation-Contraction Coupling
Initiation and propagation of

action potential along the sarcolemma and T-tubules (continued)
Action potential propagated along sarcolemma and T-tubules
inflow of Na+ at initial portion of sarcolemma
causes adjacent regions to experience electrical changes
initiate voltage-gated Na+ channels in this region to open
action potential propagated down the sarcolemma and t-tubules
Refractory period
time between depolarization and repolarization
muscle unable to be restimulated

Слайд 89

Skeletal Muscle Contraction—Sarcolemma, T-Tubules, Sarcoplasmic Reticulum: Excitation-Contraction Coupling
Release of calcium from

the sarcoplasmic reticulum
Opening of voltage-gated Ca2+ channels
found in terminal cisternae of sarcoplasmic reticulum
triggered by action potential
Diffusion of Ca2+ out of cisternae
Diffusion of Ca2+ into sarcoplasm
Now interacts with thick and thin filaments

Слайд 90

Inc. Permission required for reproduction or display.

Synaptic
cleft

Voltage-gated
Na+ channel

Voltage-gated
K+ channel

Interstitial fluid

Sarcolemma

Voltage-gated
Na+ channel

Voltage-gated
K+ channel

EPP

Sarcolemma

Terminal cisterna
of sarcoplasmic
reticulum

T-tubule

SARCOLEMMA, T-TUBULES, AND SARCOPLASMIC RETICULUM:
EXCITATION-CONTRACTION COUPLING

Development of an end-plate potential (EPP) at the motor end plate

Binding of ACh to ACh receptors in the motor end plate triggers the opening
of these chemically gated ion channels. Na+ rapidly diffuses into and K+
slowly diffuses out of the muscle fiber.

The result is a reversal in the electrical charge difference across the
membrane of a muscle fiber at the motor end plate, which is called
an end-plate potential (EPP). (The inside which was negative is now
positive.)

Initiation and propagation of an action potential
along sarcolemma and T-tubules

An action potential is propagated along the sarcolemma
and T-tubules.

First, voltage-gated Na+ channels open, and Na+ moves
in to cause depolarization.

Second, voltage-gated K+ channels open, and K+ moves
out to cause repolarization.

Release of Ca2+ from the
sarcoplasmic reticulum

When the action potential reaches
the sarcoplasmic reticulum, it
triggers the opening of
voltage-gated Ca2+ channels
located in the terminal cisternae
of the sarcoplasmic reticulum

Ca2+ diffuses out of the cisternae
sarcoplasmic reticulum into the
sarcoplasm.

Ca2+

Terminal cisterna

Voltage-gated
Ca2+ channels

ACh
receptor

ACh

Na+

–

K+

Sarcoplasm

Motor end plate

Muscle Tissue

Содержание

Muscle TissueMuscles tissue distributed almost everywhereSome functions of muscular tissuePropels food

Muscle TissueThree types of muscle tissue:Skeletal muscle, cardiac muscle, smooth muscleComposes

3 Types of Muscle TissueSkeletalSmoothCardiac

Introduction to Skeletal Muscle: Functions of Skeletal MuscleFunctions of Skeletal Muscle

Introduction to Skeletal Muscle: Functions of Skeletal MuscleBody movement, maintenance of

Introduction to Skeletal Muscle: Characteristics Skeletal Muscle TissueCharacteristicsExcitabilityresponsive to nervous system

Introduction to Skeletal Muscle: Characteristics Skeletal Muscle TissueCharacteristics (continued)Elasticitydue to protein

Anatomy of Skeletal Muscle: Gross AnatomySkeletal muscleComposed of thousands of muscle

Skeletal Muscle High MagnificationNucleiA bandI band

Anatomy of Skeletal Muscle: Gross AnatomyConnective tissue componentsThree concentric layers of

Anatomy of Skeletal Muscle: Gross AnatomyConnective tissue components (continued)Epimysiumlayer of dense

Connective Tissue and FasciclesEpimysiumPerimysiumFascicleEndomysiumEpimysium + Perimysium + Endomysium = Tendon

Anatomy of Skeletal Muscle: Gross AnatomyConnective tissue components (continued)Tendoncordlike structure composed

Tendon and Aponeurosis of Palmaris Longus muscle

Anatomy of Skeletal Muscle: Gross AnatomyConnective tissue components (continued)Deep fasciaadditional sheet

Superficial and Deep Fasciae10-SuperficialDeep

Anatomy of Skeletal Muscle: Gross AnatomyConnective tissue components (continued)Superficial fasciasuperficial to

Skin

Superficial Fascia

Deep Fascia

Superficial Muscles

Deeper Muscles

Even Deeper Muscles

Yet Even Deeper Muscles

Soft Tissue and Bone

Bone

Anatomy of Skeletal Muscle: Gross AnatomyBlood vessels and nervesSkeletal muscles vascularized

Structural Organization of Skeletal Muscle (Figure 10.1)Copyright © The McGraw-Hill Companies, Inc.

Anatomy of Skeletal Muscle: Gross AnatomyThe endomysium is the layer of

Anatomy of Skeletal Muscle: Microscopic AnatomySarcoplasmaCytoplasm of muscle fibers (cells comprising

Anatomy of Skeletal Muscle: Microscopic AnatomyMultinucleated cellElongated cells extending length of

Anatomy of Skeletal Muscle: Microscopic AnatomyMultinucleatedcell (continued)Satellite cellsmyoblasts remaining, unfused, in

Anatomy of Skeletal Muscle: Microscopic AnatomySarcolemma and T-tubulesPlasma membrane of a

Anatomy of Skeletal Muscle: Microscopic AnatomySarcolemma and T-tubules (continued)Na+/ K+ pumps

Anatomy of Skeletal Muscle: Microscopic AnatomySarcolemma and T-tubules (continued)Voltage-gated Na+ channels

Anatomy of Skeletal Muscle: Microscopic AnatomySarcoplasmic reticulumInternal membrane complex Similar to

Structure and Organization of a Skeletal Muscle Fiber: Sarcolemma and T-Tubules

Sarcoplasmic reticulum (continued)Ca2+ pumps embedded in sarcoplasmic reticulummove Ca2+ into sarcoplasmic

Anatomy of Skeletal Muscle: Microscopic AnatomyMuscle fibers and myofibrilsMyofibrilslong cylindrical structures

Structure and Organization of a Skeletal Muscle Fiber (Figure 10.3 a)Copyright

Anatomy of Skeletal Muscle: Microscopic AnatomyMuscle fibers and myofibrils (continued)Thick filaments

Anatomy of Skeletal Muscle: Microscopic AnatomyMuscle fibers and myofibrils (continued)Thin filamentsPrimarily

Anatomy of Skeletal Muscle: Microscopic AnatomyMuscle fibers and myofibrils Thin filaments

Molecular Structure of Thick and Thin Filaments (Figure 10.4)Copyright © The McGraw-Hill

Anatomy of Skeletal Muscle: Microscopic AnatomyOrganization of a sarcomereMyofilaments arranged in

Anatomy of Skeletal Muscle: Microscopic AnatomyOrganization of a sarcomereOverlapping filaments (continued)Form

Skeletal Muscle (striations)Skeletal muscle fiberA bandI bandNuclei

SarcomereA bandH bandI bandM lineMyofibrilSarcomereZ disc

Structure of a Sarcomere (Figure 10.5 a)Copyright © The McGraw-Hill Companies,

Anatomy of Skeletal Muscle: Microscopic AnatomyOrganization of a sarcomere (continued)Overlapping filamentsI

Anatomy of Skeletal Muscle: Microscopic AnatomyOrganization of a sarcomereOverlapping filaments (continued)A

Anatomy of Skeletal Muscle: Microscopic AnatomyOrganization of a sarcomereOverlapping filaments (continued)H

Structure of a Sarcomere (Figure 10.5 b)Copyright © The McGraw-Hill Companies,

Structure of a Sarcomere (Figure 10.5 c)Copyright © The McGraw-Hill Companies,

Anatomy of Skeletal Muscle: Microscopic AnatomyOrganization of a sarcomereOther structural and

Anatomy of Skeletal Muscle: Microscopic AnatomyOrganization of a sarcomereOther structural and

Anatomy of Skeletal Muscle: Microscopic AnatomyMitochondria and other structures associated with

Anatomy of Skeletal Muscle: Microscopic AnatomyMitochondria and other structures associated with

Anatomy of Skeletal Muscle: Microscopic AnatomyThick filaments are composed of myosin

Anatomy of Skeletal Muscle: Microscopic AnatomyH zoneIn which band are there

Anatomy of Skeletal Muscle: Innervation of Skeletal Muscle FibersMotor unitMotor neuron

Anatomy of Skeletal Muscle: Innervation of Skeletal Muscle FibersMotor unit (continued)Varied

Anatomy of Skeletal Muscle: Innervation of Skeletal Muscle FibersMotor unit (continued)Fibers

Anatomy of Skeletal Muscle: Innervation of Skeletal Muscle FibersNeuromuscular junctionsLocation where

Neuromuscular Junction High MagnificationSkeletal muscle fiberAxon of motor nerveMotor end plate

Anatomy of Skeletal Muscle: Innervation of Skeletal Muscle FibersNeuromuscular junctions (continued)Synaptic

Neuromuscular Junction TEM: High Magnification Primary synaptic cleftSynaptic vesicles of synaptic terminalSecondary

Anatomy of Skeletal Muscle: Innervation of Skeletal Muscle FibersNeuromuscular junctionsSynaptic knob

Anatomy of Skeletal Muscle: Innervation of Skeletal Muscle FibersNeuromuscular junctionsMotor end

Anatomy of Skeletal Muscle: Innervation of Skeletal Muscle FibersNeuromuscular junctions (continued)Synaptic

Structure and Organization of a Neuromuscular Junction (Figure 10.7a)NeuromuscularjunctionNerve signalSynapticcleftEndomysiumSarcolemma(a)Synaptic knobMyofibrilMyofilamentsMotor endplateCopyright

Structure and Organization of a Neuromuscular Junction (Figure 10.7b)K+(b)Interstitial fluidCa2+ pumpVoltage-gatedCa2+ channelsSarcolemmaSynaptic

Anatomy of Skeletal Muscle: Innervation of Skeletal Muscle FibersA motor unit

Physiology of Skeletal Muscle ContractionDuring muscle contractionProtein filaments within sarcomeres interactSarcomeres

Muscle Tissue
Muscles tissue distributed almost everywhere
Some functions of muscular tissue
Propels food

Muscle Tissue
Three types of muscle tissue:
Skeletal muscle, cardiac muscle, smooth muscle
Composes

3 Types of Muscle Tissue
Skeletal
Smooth
Cardiac

Introduction to Skeletal Muscle: Functions of Skeletal Muscle
Functions of Skeletal Muscle

Introduction to Skeletal Muscle: Functions of Skeletal Muscle
Body movement, maintenance of

Introduction to Skeletal Muscle: Characteristics Skeletal Muscle Tissue
Characteristics
Excitability
responsive to nervous system

Introduction to Skeletal Muscle: Characteristics Skeletal Muscle Tissue
Characteristics (continued)
Elasticity
due to protein

Anatomy of Skeletal Muscle: Gross Anatomy
Skeletal muscle
Composed of thousands of muscle

Skeletal Muscle High Magnification
Nuclei
A band
I band

Anatomy of Skeletal Muscle: Gross Anatomy
Connective tissue components
Three concentric layers of

Anatomy of Skeletal Muscle: Gross Anatomy
Connective tissue components (continued)
Epimysium
layer of dense

Connective Tissue and Fascicles
Epimysium
Perimysium
Fascicle
Endomysium
Epimysium + Perimysium + Endomysium = Tendon

Anatomy of Skeletal Muscle: Gross Anatomy
Connective tissue components (continued)
Tendon
cordlike structure composed

Anatomy of Skeletal Muscle: Gross Anatomy
Connective tissue components (continued)
Deep fascia
additional sheet

Superficial and Deep Fasciae
10-
Superficial
Deep

Anatomy of Skeletal Muscle: Gross Anatomy
Connective tissue components (continued)
Superficial fascia
superficial to

Anatomy of Skeletal Muscle: Gross Anatomy
Blood vessels and nerves
Skeletal muscles vascularized

Structural Organization of Skeletal Muscle (Figure 10.1)
Copyright © The McGraw-Hill Companies, Inc.

Anatomy of Skeletal Muscle: Gross Anatomy
The endomysium is the layer of

Anatomy of Skeletal Muscle: Microscopic Anatomy
Sarcoplasma
Cytoplasm of muscle fibers (cells comprising

Anatomy of Skeletal Muscle: Microscopic Anatomy
Multinucleated cell
Elongated cells extending length of

Anatomy of Skeletal Muscle: Microscopic Anatomy
Multinucleated
cell (continued)
Satellite cells
myoblasts remaining, unfused, in

Anatomy of Skeletal Muscle: Microscopic Anatomy
Sarcolemma and T-tubules
Plasma membrane of a

Anatomy of Skeletal Muscle: Microscopic Anatomy
Sarcolemma and T-tubules (continued)
Na+/ K+ pumps

Anatomy of Skeletal Muscle: Microscopic Anatomy
Sarcolemma and T-tubules (continued)
Voltage-gated Na+ channels

Anatomy of Skeletal Muscle: Microscopic Anatomy
Sarcoplasmic reticulum
Internal membrane complex
Similar to

Sarcoplasmic reticulum (continued)
Ca2+ pumps embedded in sarcoplasmic reticulum
move Ca2+ into sarcoplasmic

Anatomy of Skeletal Muscle: Microscopic Anatomy
Muscle fibers and myofibrils
Myofibrils
long cylindrical structures

Structure and Organization of a Skeletal Muscle Fiber (Figure 10.3 a)
Copyright

Anatomy of Skeletal Muscle: Microscopic Anatomy
Muscle fibers and myofibrils (continued)
Thick filaments

Anatomy of Skeletal Muscle: Microscopic Anatomy
Muscle fibers and myofibrils (continued)
Thin filaments
Primarily

Anatomy of Skeletal Muscle: Microscopic Anatomy
Muscle fibers and myofibrils
Thin filaments

Molecular Structure of Thick and Thin Filaments (Figure 10.4)
Copyright © The McGraw-Hill

Anatomy of Skeletal Muscle: Microscopic Anatomy
Organization of a sarcomere
Myofilaments arranged in

Anatomy of Skeletal Muscle: Microscopic Anatomy
Organization of a sarcomere
Overlapping filaments (continued)
Form

Skeletal Muscle (striations)
Skeletal muscle fiber
A band
I band
Nuclei

Sarcomere
A band
H band
I band
M line
Myofibril
Sarcomere
Z disc

Structure of a Sarcomere (Figure 10.5 a)
Copyright © The McGraw-Hill Companies,

Anatomy of Skeletal Muscle: Microscopic Anatomy
Organization of a sarcomere (continued)
Overlapping filaments
I

Anatomy of Skeletal Muscle: Microscopic Anatomy
Organization of a sarcomere
Overlapping filaments (continued)
A

Anatomy of Skeletal Muscle: Microscopic Anatomy
Organization of a sarcomere
Overlapping filaments (continued)
H

Structure of a Sarcomere (Figure 10.5 b)
Copyright © The McGraw-Hill Companies,

Structure of a Sarcomere (Figure 10.5 c)
Copyright © The McGraw-Hill Companies,

Anatomy of Skeletal Muscle: Microscopic Anatomy
Organization of a sarcomere
Other structural and

Anatomy of Skeletal Muscle: Microscopic Anatomy
Organization of a sarcomere
Other structural and

Anatomy of Skeletal Muscle: Microscopic Anatomy
Mitochondria and other structures associated with

Anatomy of Skeletal Muscle: Microscopic Anatomy
Mitochondria and other structures associated with

Anatomy of Skeletal Muscle: Microscopic Anatomy
Thick filaments are composed of myosin

Anatomy of Skeletal Muscle: Microscopic Anatomy
H zone
In which band are there

Anatomy of Skeletal Muscle: Innervation of Skeletal Muscle Fibers
Motor unit
Motor neuron

Anatomy of Skeletal Muscle: Innervation of Skeletal Muscle Fibers
Motor unit (continued)
Varied

Anatomy of Skeletal Muscle: Innervation of Skeletal Muscle Fibers
Motor unit (continued)
Fibers

Anatomy of Skeletal Muscle: Innervation of Skeletal Muscle Fibers
Neuromuscular junctions
Location where

Neuromuscular Junction High Magnification
Skeletal muscle fiber
Axon of motor nerve
Motor end plate

Anatomy of Skeletal Muscle: Innervation of Skeletal Muscle Fibers
Neuromuscular junctions (continued)
Synaptic

Neuromuscular Junction TEM: High Magnification
Primary synaptic cleft
Synaptic vesicles of synaptic terminal
Secondary

Anatomy of Skeletal Muscle: Innervation of Skeletal Muscle Fibers
Neuromuscular junctions
Synaptic knob

Anatomy of Skeletal Muscle: Innervation of Skeletal Muscle Fibers
Neuromuscular junctions
Motor end

Anatomy of Skeletal Muscle: Innervation of Skeletal Muscle Fibers
Neuromuscular junctions (continued)
Synaptic

Structure and Organization of a Neuromuscular Junction (Figure 10.7a)
Neuromuscular
junction
Nerve signal
Synaptic
cleft
Endomysium
Sarcolemma
(a)
Synaptic knob
Myofibril
Myofilaments
Motor end
plate
Copyright

Structure and Organization of a Neuromuscular Junction (Figure 10.7b)
K+
(b)
Interstitial fluid
Ca2+ pump
Voltage-gated
Ca2+ channels
Sarcolemma
Synaptic

Anatomy of Skeletal Muscle: Innervation of Skeletal Muscle Fibers
A motor unit

Physiology of Skeletal Muscle Contraction
During muscle contraction
Protein filaments within sarcomeres interact
Sarcomeres