1. Anatomy & Physiology B
Muscular System 1

2. Remember from last Trimester?
What are the three types of muscle tissue?
Where are each located?
Which are voluntary and which are involuntary?
Which are striated which are unstriated?
Which are multinucleated?

3. 3 Types of Muscle Tissue Skeletal muscle multinucleated
attaches to bone, skin or fascia
striated with light & dark bands visible with scope
voluntary control of contraction & relaxation

4. 3 Types of Muscle Tissue Cardiac muscle striated in appearance
involuntary control
Uninucleated
autorhythmic because of built in pacemaker

5. 3 Types of Muscle Tissue Smooth muscle Uninucleated
attached to hair follicles in skin
in walls of hollow organs -- blood vessels & GI
nonstriated in appearance
involuntary

6. Structure and Organization
600 Human skeletal muscles
Regional descriptions
functions of muscle
general anatomy of skeletal muscles
muscle shape and function
coordinated actions of muscle groups

7. Muscle Tissue Alternating contraction and relaxation of cells
Chemical energy changed into mechanical energy

8. What are the functions of Muscles?
Producing body movements
Stabilizing body positions
Regulating organ volumes
bands of smooth muscle called sphincters
Movement of substances within the body
blood, lymph, urine, air, food and fluids, sperm
Producing heat
involuntary contractions of skeletal muscle (shivering)

9. Connective Tissue Components

10. Connective Tissues of a Muscle
Epimysium
covers whole muscle belly
blends into connective tissue that separates muscles
Perimysium
slightly thicker layer of connective tissue
surrounds a bundle of cells called a fascicle
Endomysium
thin layer of areolar tissue surrounding each cell
allows room for capillaries and nerve fibers

11. Myofibrils & Myofilaments
Muscle fibers are filled with threads called myofibrils
Myofilaments (thick & thin filaments) are the contractile proteins of muscle

12. Filaments and the Sarcomere
A bands Thick and thin filaments overlap each other in a pattern that creates dark band, six thin filaments surround each thick filament
I bands – light bands, contains only thin filaments
Sarcomeres - compartments separated by Z discs.
I A I

13. Overlap of Thick & Thin Myofilaments within a Myofibril
Dark(A) & light(I) bands visible with an electron microscope

14. Thick & Thin Myofilaments
Supporting proteins (M line, titin and Z disc help anchor the thick and thin filaments in place)

15. Thick Filaments : Myosin
Made of 200 to 500 myosin molecules
Arranged in a bundle with heads (cross bridges) directed outward in a spiral array around the bundled tails
central area is a bare zone with no heads

16. Thin Filaments : Actin
Two intertwined strands of fibrous (F) actin

17. A Band Overlap of Thick & Thin Filaments

18. Striations and Sarcomeres

19. Relaxed versus Contracted Sarcomere
Muscle cells shorten because their individual sarcomeres shorten
pulling Z discs closer together
pulls on sarcolemma
Notice neither thick nor thick filaments change length during shortening
Their overlap changes as sarcomeres shorten

20. Muscle Tissue Components

21. Now work with it …… Textbook : Read pp. 154 - 162 Packet
Fill in p. 2-4 in packet
Color p. 5

22. MYOFILAMENTS MYOSIN ACTIN SARCOMERE MYOFIBRILS MUSCLE FIBERS (CELLS)
__________________
Threadlike Protein that consist of:
MYOFILAMENTS
MYOSIN
ACTIN
____________: Dark Bands provide energy for movement
_________: Light Bands
__________________
Contractile Units made of Actin and Myosin that make up:
SARCOMERE
__________________
Which are Organelles found in
MYOFIBRILS
__________________
Which have a plasma membrane called a
MUSCLE FIBERS (CELLS)
__________________
“Muscle Husk” which is wrapped in
SARCOLEMMA
__________________
Which is connective tissue that covers the muscle cell
ENDOMYSIUM

23. ENDOMYSIUM PERIMYSIUM FASCICLE EPIMYSIUM TENDON APONEUROSIS
__________________
Which is connective tissue that covers the muscle cell
ENDOMYSIUM
__________________
Connective tissue that bundles the muscle fibers together to form a:
PERIMYSIUM
__________________
Structure of bundled muscle fibers; many fascicles are bound together by a tough connective tissue called
FASCICLE
__________________
Which cover the entire muscle and blends into
EPIMYSIUM
TENDON
__________________
Cord of Connective tissue to connect muscle to bone
APONEUROSIS
__________________
“Sheet of connective tissue

24. Aponeurosis Bicipital Aponeurosis Epicranial Aponeurosis
Palmar Aponeurosis

25. Origin and Insertion
Origin: The place where the fixed end attaches to a bone, cartilage, or connective tissue.
Insertion: The site where the movable end attaches to another structure.

26. Origin and Insertion
The tendon at the non-moving (or fixed) end is known as the origin.
The tendon at the moving end is known as the insertion.
Muscles pull by contracting – they cannot push to produce the opposite movement.

27. MOTION TERMS
FLEXION: reduces the angle of the joint from the anatomical position. Flex elbow
EXTENSION: movement that returns you to anatomical position. Extend elbow.

28. MOTION TERMS
ABDUCTION: move body part away from midline; arm, fingers, thumb
ADDUCTION: bring back to midline; arms, fingers, thumb

29. MOTION TERMS
ROTATION: pivot on an axis; shake head “no”; can rotate head and shoulder
CIRCUMDUCTION: to draw a circle with body part; shoulder, head

30. MOTION TERMS
PRONATION (to lie prone is on stomach). Turn hands downward.
SUPINATION: refers to arms; want a bowl of soup, supinate

31. ANKLE MOTION TERMS
Some terms relate only to certain areas, such as the ankle:
INVERSION: when sole of foot points inward
EVERSION: sole of foot points outward.
DORSIFLEXION: lift up toes
PLANTARFLEXION: move toes down

32. Coordinated Muscle Actions
Prime Mover : agonist, produces most of force
Synergist : aids the prime mover
stabilizes the nearby joint
modifies the direction of movement that occurs
Antagonist
opposes the prime mover
preventing excessive movement and injury
Fixator
prevents movement of bone that prime mover is attached to
Prime mover or agonist
produces most of force
Synergist aids the prime mover
stabilizes the nearby joint
modifies the direction of movement that occurs
Antagonist
opposes the prime mover
preventing excessive movement and injury
Fixator
prevents movement of bone that prime mover is attached to

33. Muscle Actions for Elbow Flexion
Prime mover (agonist) = biceps brachii m.
Synergist = brachialis m.
Antagonist = triceps brachii m.
Fixator = muscle that holds scapula firmly in place such as rhomboideus m.
Definitions

34. How Muscles are Named? Nomina Anatomica
system of Latin names developed in 1895
updated since then
English names for muscles are slight modifications of the Latin names.

35. Naming Skeletal Muscles
Location of muscle – bone or body region associated with the muscle
Shape of muscle – e.g., the deltoid muscle (deltoid = triangle)
Relative size – e.g., maximus (largest), minimus (smallest), longus (long)
Direction of fibers – e.g., rectus (fibers run straight), transversus, and oblique (fibers run at angles to an imaginary defined axis)

36. Naming Skeletal Muscles
Number of origins – e.g., biceps (two origins) and triceps (three origins)
Location of attachments – named according to point of origin or insertion (sternocleidomastoid)
Action – e.g., flexor or extensor, as in the names of muscles that flex or extend, respectively (extensor digitorum)

37. Skeletal Muscle Shapes Arrangement of Fascicles
Fusiform muscles
thick in middle & tapered at ends
biceps brachii m.
Convergent muscle
broad at origin and tapering to a narrower insertion
Parallel muscles
parallel fascicles
rectus abdominis m.
Fusiform muscles
thick in middle & tapered at ends
biceps brachii m.
Convergent muscle
broad at origin and tapering to a narrower insertion
Parallel muscles
parallel fascicles
rectus abdominis m.

38. Skeletal Muscle Shapes (2)
Circular muscles
act as sphincters
ring around body opening
orbicularis oris m.
Pennate muscles
fascicles insert obliquely on a tendon
unipennate, bipennate or multipennate
palmar interosseus m., rectus femoris m. & deltoid m.
Circular muscles
act as sphincters
ring around body opening
orbicularis oris
Pennate muscles
fascicles insert obliquely on a tendon
unipennate, bipennate or multipennate
palmar interosseus, rectus femoris & deltoid

39. Muscles are Not Boring
Figure 10.4b