Download 11-4 Naming Skeletal Muscles

Chapter 10, reviewed and continued
• Gross and microscopic anatomy of skeletal muscles
• Nerve to muscle: excitation-contraction coupling
• Factors affecting how much force is exerted
• Muscle diversity
• fast-twitch vs. slow-twitch
• skeletal vs. cardiac vs. smooth
Muscle metabolism, continued…
A new sports drink advertises, “Includes ATP for
rapid fueling of exercising muscles!”
Are you tempted to buy it? Why or why not?
© 2015 Pearson Education, Inc.
Fast-Twitch vs. Slow-Twitch Muscle Fibers
Fast-Twitch
Overall function (speed?
strength? endurance?)
Myosin type
(I? II?)
SR abundance
(low? high?)
Mitochondrial density
(low? high?)
Capillary density
(low? high?)
Substrates used
(carbs? lipids?)
Slow-Twitch
Can exercise training convert fast fibers to slow fibers or
vice versa? (Or are we prisoners of our genes?)
The heart: the ultimate
slow-twitch muscle
10th Martini,
Figure 10-22
Intercalated discs
• Intertwined cell membranes of adjacent cells
• Gap junctions
• Desmosomes
High levels of troponin have been found in a
patient’s blood. What could this mean?
Smooth
muscle
Relaxed (sectional view)
Relaxed (superficial view)
Contracted (superficial view)
10th Martini,
Figure 10-23b
Skeletal vs. Cardiac vs. Smooth (Table 10-3)
Property
Fiber size
Nuclei
Organization of
contractile proteins
Control mechanism
Calcium source
Calcium regulation
Contraction
speed/endurance
Energy source
Skeletal Muscle
Cardiac Muscle
Smooth Muscle
Clinical Case:
myasthenia gravis
• Usually an autoimmune
disease (can you think of
others?)
• Acetylcholine (Ach)
receptors are attacked
• Treatment strategies?
Figure 10-9
Worksheet: end-of-chapter review questions
10th Martini, Chapter 11: An Introduction to
the Muscular System
• General concepts
• Fascicle arrangements
• Levers
• Naming conventions
• Lots and lots of muscles!
Muscle
fascicles are
arranged in
different ways
PARALLEL
PENNATE
CONVERGENT
CIRCULAR
contracted
10th Martini, Figure 11-1
relaxed
11-1 Fascicle Arrangement
• Circular Muscles
• Also called sphincters
• Open and close to guard entrances of body
• For example, orbicularis oris muscle of the mouth
© 2015 Pearson Education, Inc.
Parallel vs. Pennate:
How does this affect muscle function?
On page 334, your textbook says:
“A pennate muscle contains more muscle fibers – and thus
more myofibrils – than does a parallel muscle of the same
size. For this reason, the pennate muscle produces more
tension.”
This is completely wrong!
Parallel vs. Pennate Muscles: a better explanation?
= 1 “unit” of muscle proteins (relaxed)
bone
bone
bone
bone
contract
bone
bone
contract
bone
bone
bone
bone
contract
bone
bone
Muscles and Levers
• Lever = “a rigid structure … that moves on a fixed
point called a fulcrum”
• Levers move when an applied force (AF)
overcomes any load (L) that would prevent
movement
• Bones are levers
• Joints are fulcrums
• Muscles provide applied force
10th Martini, Figure 11-2
Optimized for speed or effective force?
10th Martini,
Figure 11-2
11-3 Muscle Attachments to Other Tissues
• Origins and Insertions
•
•
•
•
Origin: fixed point of attachment
Insertion: moving point of attachment
Most muscles originate or insert on the skeleton
Origin is usually proximal to insertion
“Knowing which end is the origin and which is the insertion is
ultimately less important than knowing where the two ends attach
and what the muscle accomplishes when it contracts.”
© 2015 Pearson Education, Inc.
11-3 Muscle Attachments to Other Tissues
• Remember the movement terms from the previous lab?
(abduction/adduction, pronation/supination, etc.)
• Now we can see how muscles achieve these movements!
11-3 Muscle Attachments to Other Tissues
• Muscle Terminology Based on Function
• Agonist (or prime mover)
• Antagonist
• Synergist
Muscles you will need to know (Exercise 13)
• Muscles of Facial Expression:
•
•
•
•
•
occipitofrontalis (frontalis)
orbicularis oris
levator labii
zygomaticus
lateral rectus
• Muscles of Mastication:
• temporalis
• Muscles of Tongue, Throat, and Anterior Neck:
• sternohyoid
• sternocleidomastoid
• Muscles of the Neck and Vertebral Column:
• longissimus cervicis
• semispinalis thoracis
Muscles you will need to know (Exercise 13)
• Muscles of the Thorax: Movement of the Scapula:
•
•
•
•
levator scapulae
rhomboideus major
serratus anterior
trapezius
• Muscles of the Shoulder and Arm:
•
•
•
•
•
•
•
pectoralis major
deltoid
supraspinatus
coracobrachialis
triceps brachii
biceps brachii
brachioradialis
• flexor carpi radialis
• palmaris longus
• extensor digitorum
• adductor pollicis
Muscles you will need to know (Exercise 13)
• Muscles of the Hip and Leg:
•
•
•
•
•
•
iliacus
gluteus medius
sartorius
adductor longus
adductor magnus
quadriceps femoris:
• rectus femoris, vastus lateralis, vastus medialis, vastus intermedius
• hamstrings:
• biceps femoris, semitendinosus, semimembranosus
• tibialis anterior
• flexor digitorum longus
• gastrocnemius
11-4 Naming Skeletal Muscles
• Names for skeletal muscles can indicate any of
the following:
•
•
•
•
•
•
1. Location in the body
2. Origin and insertion
3. Fascicle organization
4. Relative position
5. Structural characteristics
6. Action
The following slides are meant to help but do not
need to be memorized.
© 2015 Pearson Education, Inc.
11-4 Naming Skeletal Muscles
1. Location in the body
• For example, temporalis muscle
2. Origin and insertion
• First part of name indicates origin
• Second part of name indicates insertion
• For example, genioglossus muscle
3. Fascicle organization
• For example, rectus (straight), transversus
(crosswise), oblique (slanting)
© 2015 Pearson Education, Inc.
11-4 Naming Skeletal Muscles
4. Position
• Externus (superficialis) =
• Internus (profundus) =
• Extrinsic
• Muscles ______ an organ
• Intrinsic
• Muscles ______ an organ
© 2015 Pearson Education, Inc.
11-4 Naming Skeletal Muscles
5. Structural characteristics
• Nature of origin
• Biceps (__ heads)
• Triceps (__ heads)
• Quadriceps (__ heads)
• Shape
•
•
•
•
•
•
Deltoid (triangle)
Orbicularis (circle)
Pectinate (comblike)
Piriformis (pear-shaped)
Platy- (flat)
Pyramidal (pyramid)
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• Rhomboid (parallelogram)
• Serratus (serrated)
• Splenius (bandage)
• Teres (round and long)
• Trapezius (trapezoid)
11-4 Naming Skeletal Muscles
5. Structural characteristics (continued)
• Other striking features
•
•
•
•
•
•
•
Alba (white)
Brevis (short)
Gracilis (slender)
Lata (wide)
Latissimus (widest)
Longissimus (longest)
Longus (long)
© 2015 Pearson Education, Inc.
• Magnus (large)
• Major (larger)
• Maximus (largest)
• Minimus (smallest)
• Minor (smaller)
• Vastus (great)
11-4 Naming Skeletal Muscles
6. Actions
•
•
•
•
•
•
•
•
•
Abductor =
Adductor =
Depressor =
Extensor =
Flexor =
Levator =
Pronator =
Supinator =
Tensor =
© 2015 Pearson Education, Inc.