MUSCULOSKELETAL PHYSIOLOGY

1. THE
MUSCULOSKELETAL
SYSTEM
ABRAHAM POKU-ADU
(abpoku24@gmail.com)
+233 (0) 244 750 064

2. THE MUSCULOSKELETAL
SYSTEM
Made up of the
Muscular System
&
Skeletal System

3. … AND THE TWO SHALL BE
ONE

4. Divided into two broad divisions;
• Axial Skeleton
• Relating to axis
• Appendicular Skeleton
• Appendage
THE SKELETAL
SYSTEM

5. • The Skeletal System is made up
of
• Bones
• Ligaments
• Cartilages
• Joints
THE SKELETAL
SYSTEM

6. FUNCTIONS OF THE SKELETAL
SYSTEM
• Provides support and shape for the body (framework)
• Protects delicate organs
• Together with attached muscles, produce movement
(locomotion)
• Storage of minerals an fats
• Helps in the formation of blood cells (hematopoiesis)

7. THE AXIAL SKELETON
The Axial Skeleton is made up of
• The Skull (Cranium)
• Ossicles of the middle ear
• Hyoid (Laryngeal) Bone
• Rib Cage + Sternum
• Vertebral Column

8. SIGNIFICANCE OF THE AXIAL SKELETON
• The function of the axial skeleton is to
• provide support and protection for for delicate organs (the brain, the
spinal cord, lungs, heart, etc).
• provide a surface for muscle attachment for movement of the head,
neck, and trunk.
• perform respiratory movements.
• stabilize parts of the appendicular skeleton.

9. THE APPENDICULAR SKELETON
The Appendicular Skeleton is
made up of
• The Shoulder girdle
• Upper limb
• Pelvic Girdle
• Lower limb

10. SIGNIFICANCE OF THE APPENDICULAR SKELETON
• The appendicular skeleton
provide support and surface
for the attachment of
muscle. This is primarily
essential for grasp and
manipulation of objects
(upper limb) and locomotion
(lower limb)

11. JOINTS OF THE SKELETAL SYSTEM
• The human skeletal system is made up of several joints at
different points of the body.
• These joints could be classified based on their structure
(composition) or degree of movements.
• Based on structure, joints are classified as fibrous, cartilaginous
or synovial.
• Based on functional movement, joints are classified as
synarthrosis, diarthrosis or apmhiarthrosis.

12. FIBROUS JOINTS
• The bones of fibrous joints are held together by fibrous
connective tissue.
• There is no cavity, or space, present between the bones and so
most fibrous joints do not move at all, or are only capable of
minor movements.

13. CARTILAGINOUS JOINTS
• Cartilaginous joints are joints in which the bones are
connected by cartilage (fibrocartilage or hyaline).
• Cartilaginous joint allows for very little movement.

14. • Synovial joints have a space between the
adjoining bones. It is referred to as the synovial
cavity and is filled with synovial fluid.
• Synovial fluid lubricates the joint, reducing
friction between the bones and allowing for
greater movement.
• The ends of the bones are covered with
articular cartilage, a hyaline cartilage, and the
entire joint is surrounded by an articular
capsule composed of connective tissue that
allows movement of the joint while resisting
dislocation.

17. BONE TO BONE ATTACHMENT
• A ligament is a fibrous connective tissue which attaches bone to
bone, and usually serves to hold structures together and keep
them stable.
• Ligaments are viscoelastic - thus gradually strain when under
tension and return to their original shape when the tension is
removed.
• However, they cannot retain their original shape when extended
beyond a threshold (time or length)
• This is one reason why dislocated joints must be set as quickly
as possible: if the ligaments lengthen too much, then the joint
will be weakened, becoming prone to future dislocations.

19. MUSCLE TO BONE ATTACHMENT
• The point at which the tendon forms attachment to the muscle is
also known as the musculotendinous junction (MTJ) and the
point at which it attaches to the bone is known as the
osteotendinous junction (OTJ).
• The proximal attachment of the tendon is also known as the
origin and the distal tendon is called the insertion.

20. • The process of bone formation is called osteogenesis or
ossification.
• After progenitor cells form osteoblastic lines, they proceed with
three stages of development of cell differentiation,
called proliferation, maturation of matrix, and
mineralization.

22. BONE HEALING

23. OSTEOPOROSIS
• Osteoporosis is a bone disease
that occurs when the body
loses too much bone, makes
too little bone, or both.
• As a result, bones become weak
and may break from a fall or, in
serious cases, from sneezing or
minor bumps.
• Osteoporosis means “porous
bone.” Viewed under a
microscope, healthy bone looks
like a honeycomb.

25. OSTEOARTHRITIS
• Osteoarthritis is the most common
form of arthritis, affecting millions
of people worldwide.
• It occurs when the protective
cartilage that cushions the ends of
the bones wears down over time.
• Although osteoarthritis can damage
any joint, the disorder most
commonly affects joints in your
hands, knees, hips and spine.

27. RHEUMATOID ARTHRITIS
• Rheumatoid arthritis, or RA, is an autoimmune and
inflammatory disease, which means that your immune system
attacks healthy cells in your body by mistake, causing
inflammation (painful swelling) in the affected parts of the body.
• RA mainly attacks the joints, usually many joints at once.

30. MUSCLE
PHYSIOLOGY

31. A MUSCLE
• Muscle is the tissue of the body which primarily functions as a
source of power.
• Latin- Musculus (Mouse)
• Muscle is a contractile (capable of or producing contraction)
tissue
• Contraction implies becoming shorter and tighter
• It contains filaments which move past each other to change
the overall size of the cell

32. FUNCTIONS OF THE MUSCLE
• Movement
• Stability
• Thermogenesis
• Respiration
• Constriction of organs and
vessels
• Heart beat

33. CLASSIFICATION OF MUSCLES
• Muscles can be classified based on striation, control or function
(situation)
• Based on striations, muscles are classified as Striated & Non-
striated
• Striations means a series of ridges or linear marks
• Based on control, muscles are classified as Voluntary &
Involuntary
• Based on situation, muscles are classified as Cardiac, Skeletal
or Smooth.

34. TYPES OF MUSCLE TISSUES
• There are three types of muscle
tissues in the body based on
situation.
• Muscle which is responsible for
moving extremities and external
areas of the body is called "skeletal
muscle"
• Heart muscle is called "cardiac
muscle”
• Muscle that is in the walls of arteries

36. FUNCTIONAL PROPERTIES OF
MUSCLES
• EXCITABILITY
• capable of response to chemical signals, stretch or other signals &
responding with electrical changes across the plasma membrane
• CONTRACTILITY
• shortens when excited stimulated
• EXTENSIBILITY
• capable of being stretched
• ELASTICITY
• returns to its original resting length after being stretched

37. SKELETAL MUSCLE
A muscle is made up of
muscle bundles which
are made up of
fascicles.
Each fascicle is made
up of numerous muscle
fibers.
Muscle fibres are also
made up of several
myofibrils.

39. FROM MUSCLE TO SARCOMERE
• Myofibrils lay parallel
• The myofibrils are also made
up of Sarcomeres which lay
in series. A single myofibril
can possess hundreds of
sarcomeres.
• Sarcomeres are the smallest
functional units of the muscle
fibre.

41. Actin Filament (Thin )
Myosin Filament (Thick)
The Sarcomere is the
contractile unit of myocytes
• Z-Line – sarcomere boundary where actin
filaments attaches to
adjourning sarcomere
• M-Line – center of sarcomere holding adjacent
myosin filaments together
• I-Band (AKA lIght band) – space between
myosin. It contains only actin.
• A-Band (AKA dArk band) – stretches the length
of myosin and contains both actin and
myosin
• H-Zone – non-overlapping areas. Contains only
myosin

42. An Electron Micrograph of a Myofibril

43. A CLOSER LOOK AT ACTIN & MYOSIN

44. What Changes Do You See?
B
A

45. OBSERVE THE CHANGES
EXPLAIN WHY THESE CHANGES
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49. MUSCLE CONTRACTION
MUSCLE STIMULATION
Exposure of Myosin Binding Site
Detachment of Myosin Head
CONTRACTION
Cross Bridging + Power Stroke

50. EXCITATION CONTRACTION
COUPLING
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51. ENERGY SOURCES FOR MUSCLE
ACTIVITY
ENERGY
SOURCE
S
GLUCOS
E
ADENOSINE
TRIPHOSPHATE
(ATP)
CREATININE
PHOSPHATE
(CP)

52. ADENOSINE TRIPHOSPHATE (ATP)
• ATP is the immediate source of energy for muscle
contraction.
• The break down of phosphate bond of ATP releases
maximum energy.
• Anaerobic glycolysis:
Glucose  2 moles of lactic acid +8ATPs.
• Aerobic glycolysis coupled with Kreb‘s cycle:
Glucose  6 CO2 + 6H2O +38 ATPs.

53. CREATINE PHOSPHATASE
• Also known as phosphagens
• Forms a reservoir of high energy phosphate in the muscle
• Cannot be used as a direct source of energy.
• Used for regeneration of ATP from ADP.
Creatine phosphate  creatine + phosphoric acid
Phosphoric acid +ADP  ATP

54. GLUCOSE
• Glucose is stored in the muscle in the form of
glycogen.
• Muscle glycogen is converted into glucose by
glycogenolysis.
• Glucose is oxidized by glycolysis.
C6H12O6 + 6O2  6CO2 + 6H2O + 38 ATP
Glucose + Oxygen  Carbon Dioxide + Water + Energy

55. TETANUS
• Tetanus is an infection caused by bacteria called
Clostridium tetani.
• When the bacteria invade the body, they produce a poison
(toxin) that causes painful muscle contractions.
• Another name for tetanus is “lockjaw”.
• It often causes a person's neck and jaw muscles to lock, making
it hard to open the mouth or swallow.

57. RIGOR MORTISE
• Rigor mortis: Literally, the
stiffness of death. The rigidity
of a body after death.
• The biochemical basis of
rigor mortis is hydrolysis in
muscle of ATP, the energy
source required for
movement.
• Without ATP, myosin
molecules adhere to actin
filaments and the muscles
become rigid.

58. ATROPHY & HYPERTROPHY
• Muscle atrophy is defined as the presence of low muscle mass
and low muscle function (strength or performance)
• If a muscle is not used, its actin and myosin content decreases,
its fibers become smaller.
• It may result from prolonged periods of rest or a sedentary
lifestyle.
• Causes of atrophy include mutations, poor nourishment, poor
circulation, loss of hormonal support, loss of nerve supply to the
target organ, excessive amount of apoptosis of cells, and
disuse or lack of exercise or disease intrinsic to the tissue itself.

59. HYPERTROPHY
• The actual size of the muscles can be increased by regular
bouts of anaerobic, short-duration, high intensity resistance
training, such as weight lifting.
• The resulting muscle enlargement comes primarily from an
increase in diameter (hypertrophy) of the fast-glycolytic fibers
called into play during such powerful contractions.
• Most fiber thickening results from increased synthesis of
myosin and actin filaments, which permits a greater opportunity
for cross-bridge interaction and consequently increases the
muscle’s contractile strength.

60. HYPERTROPHY
• The mechanical stress that resistance training exerts on a
muscle fiber triggers signaling proteins, which turn on genes
that direct the synthesis of more myosin and actin.
• Vigorous weight training can double or triple a muscle’s size.
• The resultant bulging muscles are better adapted to activities
that require intense strength for brief periods, but endurance
has not been improved.

61. MUSCLE FATIGUE
• Muscle fatigue occurs when an exercising muscle can no
longer respond to stimulation with the same degree of
contractile activity.
• Muscle fatigue is a defense mechanism that protects a muscle
from reaching a point at which it can no longer produce ATP.
• An inability to produce ATP would result in rigor mortis
(obviously not an acceptable outcome of exercise).

62. MUSCLE RECOVERY
• Muscle fibers rebuild: when you exert stress on your muscles,
it damages the muscle fibers, causing them to break apart.
• During recovery, these fibers heal stronger than they were
before, which in turn, make your muscles stronger