Download SKELETAL MUSCLE

The Muscular System
Lab 7
Expanded Studies
Objectives
• Identify the muscle types & their indicated
cellular structures from prepared slides
• Identify the portions of skeletal muscle from
diagrams, slides and models
• Identify the indicated structures of the
neuromuscular junction from a prepared slide
• Identify the human muscles from models and
diagrams
Objective 1
Types of Muscle Tissue
SKELETAL MUSCLE
Structure of SKELETAL MUSCLE
Muscle

Fascicles

Muscle Fibers (cells)

A muscle cell (fiber)
is a bundle of myofibrils
Myofibrils
Skeletal Muscle
Location
Structure
Function
Attached to the
skeleton
Long, thin cells (fibers) are:
- striated
- multinucleated
- nuclei are in the periphery
of the cell
posture, movement,
stabilizes joints
The plasma
membrane of the
muscle fiber
Skeletal Muscle
Note multi-nucleation
Whole mount, oil immersion
Skeletal Muscle
Note nuclei on the periphery of the cells (fibers)
Longitudinal section, oil immersion
Striations: A bands & I bands
(dark bands)
(light bands)
Striations in skeletal muscle due to sarcomeres
Striations of the myofibrils are seen through the muscle fiber
A-bands, I-bands, Sarcomeres, & Sarcolemma
I I I
A A A
A
I
A
A
I I
Sarcomeres
Sarcolemma
A I
Sarcomere
Your turn!
Identify these structures:
Nuclei
Sarcolemma
A-band
I-band
SKELETAL MUSCLE - Review
Muscle Fiber
I-Band
A-Band
CARDIAC MUSCLE
The heart muscle (myocardium) forms the bulk of the heart.
It is arranged in a spiral or circular bundles.
Cardiac
muscle
bundles
“Helical heart” model
Cardiac Muscle
Location
Structure
Function
Wall of the heart
Cells (myocytes) are:
provide pressure
- faintly striated
- branching
for the circulation
of blood
- with one (or two)
centrally placed nuclei
Cells are connected by intercalated discs
(gap junctions/desmosomes)
Intercalated Disc
Nucleus
Cardiac Muscle
Branching cells
Central nuclei
Intercalated
disk
Cardiac Muscle
Branching
cells
Central
nuclei
?
Intercalated disk
Cardiac Muscle –
Can you see the intercalated discs?
Intercalated discs
SMOOTH MUSCLE
Smooth muscle is found in the walls of hollow visceral organs.
Contractions force fluids and other substances along.
Cells are arranged closely to form sheets.
Epithelial Tissue
C.T.
C.T.
Connective Tissue
C. T.
Epithelial Tissue
Smooth Muscle
Location
Walls of hollow
organs
Structure
Cells are:
- spindle shaped
- have a single nucleus
- not striated
Function
move fluids
and other contents
nucleus
Smooth Muscle
Cells are arranged closely to form sheets.
Smooth Muscle
Note cell and nucleus shapes
REVIEW – Identify the muscle type of each
Cardiac muscle
Skeletal muscle
Smooth muscle
Objective 2
Connective Tissue Coverings of Skeletal Muscle
Note that the endomysium surrounds the sarcolemma
Skeletal Muscle, cs & ls
A muscle fiber is filled with
myofibrils
Cross section through a skeletal muscle
Epimysium
Perimysium
Endomysium /
muscle fiber
Epimysium
Perimysium /
Fascicle
Endomysium /
muscle fiber
Cross section through a skeletal muscle
Fascicle
Perimyseum
Endomysium
Cross section through a skeletal muscle
endomysium
Magnified image
Your turn!
Identify these:
Epimysium
Endomysium
Fascicle Perimysium
Objective 3
Neuromuscular Junction
Reflex Arc
Neuromuscular junction
(Myoneural junction)
Neuromuscular Junction
Skeletal muscle fiber
Skeletal muscle fiber
Motor Neuron Axon
Axon Terminal
Identify each structure:
Neuron
Axon
Axon Terminal
Objective 4
Human Muscles
Frontal
region
Think:
orbit
Frontalis
Orbicularis
oculi
Orbicularis
oris
Mental
region
Mentalis
Buccal
region
Buccinator
Occipitalis
Sternocleidomastoid
Sternum,
Clavicle,
Mastoid process
Masseter
Trapezius
Think:
“mass eater”
Occipital
region
Smaller muscle of the chest
Delta =
“triangular”
Pectoralis minor
Deltoid
Pectoralis major
Larger muscle of the chest
Serratus
anterior
Serratus
anterior
serrated, towards
the front
Subscapularis
Subscapular
fossa
Intercostal = between the ribs
Internal
intercostals
* Medial
External
intercostals
* External (superficial) to
the Internal intercostals
* Lateral
Deepest abdominal muscle;
Fibers run transversely
Transverse
abdominus
Rectus abdominus
Rectus = “erect”
Internal oblique
Fibers run
External oblique
Fibers run
External oblique
Most external abdominal
muscle
Think:
trapezoid or
trapeze
Trapezius
Splenius
capitis
Levator
scapulae
Caput = “head”
Think: Cap
Elevates the
scapula
Supraspinatus
Infraspinatus
Teres
major
Below the spine
of the scapula
Infraspinatus
Rhomboid
minor
Rhomboid
major
Latissimus = widest
Dorsi = “back”
Think: Lat - lateral
Latissumus
dorsi
Above the spine
of the scapula
Below the spine
of the scapula
Splenion = “bandage”
Caput = “head”
Splenius
capitis
Elevates the scapula
Levator
scapulae
Supraspinatus
Teres
minor
Infraspinatus
Teres
major
Teres = “round”
Major = “larger”
Minor = “lesser”
Teres
major
Infraspinatus
Supraspinous
fossa
Infraspinous
fossa
Rhomboid
minor
Rhomboid =
“diamond-shaped”
Muscles that
“squares the
Rhomboid shoulders”
major
Longissimus
External
intercostals
(longest)
Iliocostalis
(most lateral)
Ilium + Costals
Semispinalis
Spinalis
(most medial)
(along spine)
Anterior
Iliopsoas
Psoas major
Iliacus = Ilium
Iliacus
Thigh adductors:
Tensor = tension
Tensor
fasciae
latae
Pectineus
Latae – Think: latte
Pecten = “comb”
Adductor
longus
Rectus = “erect”
Vastus
lateralis
Rectus
femoris
Vastus
medialis
Pectineus
Adductors
Gracilis
Femoris = femur
Gracilis = “slender”
~~
Gracilis
Sartorius
Vastus = “vast” (large)
Lateralis = lateral
Medialis = medial
Sartor = “tailor”
Tailor’s muscle –
cross-legged position
Anterior
Anterior
deep
Adductor = adducts the thigh
Brevis = “short”
Longus = “long”
Adductor
magnus
Pectineus
Adductor
brevis
Magnus = “large”
Adductor
longus
Most superficial of
the adductors
Adductor
longus
Adductor
magnus
Gracilis
Deepest of the
adductors;
Extends the entire
diaphysis of the femur
Posterior
Glutos = “buttock”
Minimus = “smallest”
Gluteus
minimus
Biceps = “2 heads”
Femoris – femur
Rectus = “erect”
Femoris = femur
Semi = “half”
Adductor
magnus
Gracilis
Tendinosus = “tendon”
Semimembranosus
Semitendinosus
Membranosus = “membrane”
Biceps
femoris
(Medial)
(Lateral)
Think: TM (trademark)
“T” is superficial to “M”
Anterior
to the
tibia
Tibialis
anterior
Extensor
digitorum
longus
Think:
gas
truck
knee
me
us
Posterior
to the
tibia
Gastrocnemius
Tibialis
posterior
Soleus
Fibularis
longus
Fibularis
longus
Fibularis
brevis
Extensor
halicus
longus
Flexor
digitorum
longus
Fibularis
brevis
Subscapularis
Subscapular
fossa
Biceps
brachii
2 heads
Biceps
brachii
Brachialis
Brachialis
Brachi = “arm”
Brachioradialis
Brachialis
Brachioradialis
Brachioradialis
E.C.R. longus
E.C.R. brevis
Longus = “long”
Extensor carpi
radialis longus
Extensor carpi
radialis brevis
Brevis = “short”
Extensor
carpi =
Pronates
Pronator teres
Flexes the
carpals along Flexor carpi
the radius radialis
To the
center of
the palm
Palmaris longus
Flexes the Flexor carpi
carpals along ulnaris
the ulna
Extensor
digitorum
Originates “higher”
up the brachial
region than the
others
Brachial + Radius
Brachioradialis
Supinates
Supinator
Extends
the digits
Extensor carpi
ulnaris
Extends the
carpals along
the ulna
extends the
wrist
Pronator
teres
How
many of
these
muscles
can you
name?
See next slide
Identify
the
muscles
1
Frontalis
Masseter 11
Mentalis
2
Sternocleidomastoid
12
Deltoid
13
Triceps Brachii
14
Pectoralis
3 major
Extensor carpi
15radialis longus
Biceps
4 Brachii
Extensor carpi
16radialis brevis
Extensor digitorum
17
5
Rectus abdominus
18dorsi
Latissimus
Serratus 19
anterior
Rectus
6 femoris
External 20
oblique
7 lateralis
Vastus
21
Tensor fasciae
latae
Biceps femoris
22
8 anterior
Tibialis
Extensor digitorum
longus
9
Fibularis
10
longus
Soleus23
Gastrocnemius
24