Chapters 12 & 13 Slides PDF.pdf medicine

Skeletal system

1. CHAPTER 12
SKELETAL
SYSTEM

2. 2
THE BIG PICTURE
•The skeletal system protect, supports, and defends
the body

•Bones are capable of growth, remodeling, and
repair

•Axial skeleton elements protect vital organs

•Appendicular skeletal elements form the
extremities of arms and legs

•Synovial joints allow for movement

3. 3
SKELETAL SYSTEM FUNCTIONS INCLUDE SUPPORT,
MOVEMENT, PROTECTION, STORAGE, & BLOOD
1.Supports the body
2.Allows for movement
by attaching muscles
3.Protects the soft body
parts
4.Produce blood cells
5.Stores minerals
(calcium and
phosphate) and fat

4. 4
ANATOMY OF A LONG BONE REVEALS ITS MANY
FUNCTIONS
Figure 12.1 The anatomy of a long bone.

Red bone marrow
in spongy bone &
flat bones









Articular cartilage –
hyaline cartilage on
the articulating ends
of long bones
Epiphysis ends are
made of spongy bone


Periosteum – living,
outer covering of
fibrous connective
tissue


Diaphysis is the
compact bone shaft
filled with yellow
marrow

Ligaments – fibrous
connective tissue that
connects bones

5. 5
DETAILS OF BONES SHOW CELLS WITHIN A RIGID
MATRIX
Figure 12.1 The anatomy of
a long bone.
•Osteons contain living
osteocytes

•Osteocytes secrete the
minerals that make up
the bone matrix

•Osteons empty waste,
receive nutrients via their
blood supply

6. 6
THERE ARE 206 BONES OF THE SKELETON
Figure 12.2 The axial and appendicular skeletons.

7. 7 Figure 12.3 The bones of the skull.
PART OF THE AXIAL SKELETON CONSISTS OF
THE SKULL AND THE VERTEBRAL COLUMN
Skull = cranium + facial bones, plus the Hyoid bone

Vertebral column = vertebrae + intervertebral disks, plus Rib
cage (ribs and sternum)

8. 8
BONES OF THE FACE AND THE HYOID BONE
Facial bones
•Mandible
•Maxillae
•Zygomatic bones
•Nasal bones
Hyoid - Only bone that
does not articulate with
another bone

9. 9
THE VERTEBRAL COLUMN CONSISTS OF VERTEBRAE
AND DISKS
5 vertebrae types (33 total)
•Cervical (7)
•Thoracic (12)
•Lumbar (5)
•Sacrum (5 fused)
•Coccyx (4 fused into tailbone)

•Intervertebral disks -
Fibrocartilage between
vertebrae

10. 10
THE RIB CAGE PROTECTS THE HEART AND THE
LUNGS
Figure 12.6 The thoracic vertebrae, ribs, and sternum.
Rib(s) - Flattened bones
originating from the
thoracic vertebrae

•12 pairs total
•7 pairs true ribs
•3 pairs false ribs
•2 pairs floating ribs

Sternum

11. 11
THE APPENDICULAR SKELETON PECTORAL
GIRDLE ARTICULATES THE UPPER LIMBS
•Pectoral girdle
–Scapula and
clavicle
•Upper limb
–Arm and hand
bones



Figure 12.7 The bones of the pectoral girdle and upper
limb.

12. 12
•Pelvic girdle
–Coxal bone

•Lower limb
–Leg and foot bones

Figure 12.8 The coxal bones and bones of the pelvis
and lower limb.
THE APPENDICULAR SKELETON PELVIC GIRDLE
ARTICULATES THE LOWER LIMBS

13. 13
HUMAN CHARACTERISTIC MAY BE DETERMINED
FROM SKELETAL REMAINS
Characteristics to be determined

•Age - dentition, areas of bone
ossification, and joint condition.

•Gender - use the pelvic bone, and
thickness of long bones or skull
characteristics

•Ethnicity - difficult to tell, but skull
characteristics are most useful.

14. 14
SYNOVIAL JOINTS ALLOW FOR MOVEMENT WHERE
BONES MEETS BONES
Fibrous – usually immovable
Cartilaginous – tend to be
slightly movable

Synovial – freely
movable joints
•ball-and-socket hip
and shoulder joints
•hinge knee and elbow
joints

15. 15
•Flexion
•Extension
•Adduction
•Abduction

•Rotation
•Supination
•Pronation
•Circumduction

A SUMMARY OF SYNOVIAL JOINTS MOVEMENTS

16. 16
BONES ARE ABLE TO GROW, REMODEL, AND REPAIR
Four cell types:
•Osteoblasts – bone-forming
cells
•Osteocytes – mature bone
cells; maintain bone
structure of osteoblasts
•Chondroytes – form
cartilage
•Osteoclasts –absorb and
remodel bone

17. 17
BONE DEVELOPMENT OCCURS IN ONE OF TWO WAYS
Ossification forms bone in 2 distinct ways.:
1.Intramembranous ossification – bone develops between
sheets of fibrous connective tissue; used in flat bones

2.Endochondrial ossification – cartilage replaced by bone;
used by most bones

18. 18
ENDOCHONDRAL OSSIFICATION BEGINS WITH
CARTILAGE, THEN SPONGY BONE FORMS
1.Cartilage first – chondrocytes lay down hyaline
cartilage in the shape of the future bones
2.Bone collar – osteoblasts secrete bone matrix and
results in a collar made of compact bone
3.Primary ossification centers – osteoblasts are brought
interiorly by blood and lay down spongy bone

19. 19
4.Diaphysis spongy bone
absorbed by osteoclasts,
leaves medullary cavity;
secondary ossification
centers form in the
epiphyses after birth

5.Growth plate is a
cartilage band that allows
bones to lengthen
SPONGY BONE IS ABSORBED BY OSTEOCLASTS AND
FURTHER OSSIFICATION AND GROWTH CAN OCCUR

20. 20
BONES LENGTHEN FROM THE GROWTH PLATE IN
RESPONSE TO HORMONES
Figure 12.12 Increasing bone length.

21. 21
BONE REMODELING IS INVOLVED IN
BLOOD CALCIUM HOMEOSTASIS
Bone remodeling recycles
~18% of bone/year

Bone remodeling regulates
blood calcium levels via
hormones.
–Parathyroid hormone
(PTH) raises blood
calcium

–Calcitonin lowers blood
calcium.

22. 22
BONE REMODELING IS INVOLVED IN BONE REPAIR

23. 23
FRAGILE BONES FROM TISSUE LOSS IS CALLED
OSTEOPOROSIS
Osteoporotic bones are weakened from decreased
bone mass.

24. CHAPTER 13
MUSCULAR
SYSTEM

25. 25
THE BIG PICTURE
•Three types of muscle tissue are responsible for
movement within and of the body

•Muscles create motion by sliding filaments using
the energy of ATP

•Muscles are involved with the skeletal system in
homeostasis

•Muscle disorders and diseases may affect all three
muscle types

•Synovial joints allow for movement

26. 26
MUSCLES FUNCTION TO PRODUCE FORCE AND
MOTION

27. 27
Figure 13.1 The three classes of muscles in humans.
THERE ARE THREE TYPES OF MUSCLE TISSUE:
SKELETAL, SMOOTH, AND CARDIAC

28. 28
SKELETAL MUSCLES FUNCTION IN BALANCE,
MOVEMENT, AND THERMOREGULATION
1.Support the body by allowing us to stay
upright
2.Allow for movement by attaching to the
skeleton
3.Help maintain a constant body temperature
4.Assist in movement in the cardiovascular and
lymphatic vessels
5.Protect internal organs and stabilize joints

29. 29
MOVEMENT RESULTS FROM SKELETAL MUSCLES
ATTACHED TO BONES
•Tendon – connective
tissue that connects
muscle to bone

•Origin – attachment of
a muscle on a
stationary bone

•Insertion – attachment
of a muscle on a bone
that moves

30. 30
SKELETAL MUSCLES WORK TOGETHER FOR
MOVEMENT
•Antagonistic –
muscles that work in
opposite pairs

•Synergistic –
muscles working in
groups for a
common action

Figure 13.3 Skeletal muscles often work in pairs.

31. 31
EACH MUSCLE IN THE BODY IS NAMED BASED UPON
ITS CHARACTERISTICS

32. 32
MUSCLE CELLS HAVE SPECIFIC TERMINOLOGY
FOR THEIR INTERNAL STRUCTURE

33. 33
•Terminology for structure within a whole muscle
–Muscle fibers are arranged in bundles called
fascicles.

–Myofibrils are bundles of myofilaments that run the
length of a fiber.

–Myofilaments are proteins (actin and myosin) that
are arranged in repeating units.

–Sarcomeres are the repeating units of actin and
myosin found along a myofibril.
MUSCLE FIBERS/CELLS ARE HIGHLY ORGANIZED
CELLS WITH DISTINCT STRUCTURES

34. 34
MUSCLE ARCHITECTURE IS HIGHLY
STRUCTURED AND SPECIALIZED
Muscle  fascicle  myofibril 
sarcomere  myofilament

35. 35
THE SARCOMERE FILAMENTS SLIDE OVER ONE
ANOTHER DURING MUSCLE CONTRACTION
Figure 13.6 The structure of a skeletal muscle fiber.

36. 36
MUSCLE CONTRACTION BEGINS WITH A NERVE
IMPULSE & RELEASE OF NEUROTRANSMITTER
Nerve impulses
travel down a
motor neuron to a
neuromuscular
junction.

Acetylcholine
(ACh) is released
from the neuron,
binds muscle fiber.

Ach binding
stimulates the
fiber, calcium is
released from the
sarcoplasmic
reticulum.

37. 37
RELEASED CALCIUM EXPOSES MYOSIN TO ATP
WHICH NOW PULLS ACTIN FILAMENTS INWARD
Calcium combines
with troponin

Tropomyosin ‘threads’
around actin shift,
exposing myosin
binding sites.

Myosin heads bind to
actin, form cross-
bridges.

ATP binds to the
myosin heads, actin
filaments now pulled
toward center of
sarcomere - VOILÁ
contraction now
occurs!

38. 38
ATP DEPLETION AT DEATH EVENTUALLY
RESULTS IN RIGOR MORTIS
•ATP is needed to attach/detach the
myosin heads from actin.

•After death, myofibrils produce
ATP through fermentation and can
continue to contract.

•When ATP runs out, some myosin
heads are still attached and cannot
detach, causing rigor mortis.

•Rigor mortis and body temperature
may be used to estimate time of
death.

39. 39
MUSCLES CONTRACT AS UNITS OR WHOLE MUSCLES
•Motor unit – a nerve fiber and all of the muscle fibers it
stimulates

•Muscle twitch – a single contraction lasting a fraction
of a second

•Summation – an increase in muscle contraction until
the maximal sustained contraction is reached

•Tetanus – maximal sustained contraction

•Muscle tone – a continuous, partial contraction of
alternate muscle fibers causing the muscle to look firm

40. 40
VUSIALIZING OF SKELETAL MUSCLE CONTRACTION
Figure 13.9 The three phases of a single muscle twitch and how summation and tetanus increase the force of contraction.
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Force

relaxation
period
contraction
period
latent
period
Time
fatigue
tetanus
summation
Stimuli
Time
Force

b.
Stimulus
a.

41. 41
THE FUEL SOURCES FOR MUSCLE CONTRACTION ARE
IN THE MUSCLE AS WELL AS THE BLOOD
•Stored in the
muscle
–Glycogen
–Fat

•In the blood
–Glucose
–Fatty acids

0 1 2 3 4
6 0
5 0
4 0
3 0
2 0
1 0
0
Exercise time (hr)
muscle triglycerides
plasma fatty acids
blood glucose
muscle glycogen
Percentage of energy expenditure

Figure 13.10 The sources of energy for muscle contraction.

42. 42
THIS IS HOW ATP FOR MUSCLE CONTRACTION IS
ACQUIRED
Anaerobic Anaerobic Aerobic
creatine
phosphate
glycogen
glycogen
or
fatty acids
fermentation
O
2
creatine lactate CO
2 + H
2O
ATP ATP ATP
+ + +
Figure 13.11 The three pathways by which muscle cells produce the ATP energy needed for contraction.

43. 43
THERE ARE TWO FORMS OF MUSCLE FIBERS
Fast-twitch fibers
•Rely on CP and
fermentation
(anaerobic)
•Adapted for strength
•Light in color
•Few mitochondria
•Little or no myoglobin
•Fewer blood vessels
than slow-twitch

Slow-twitch fibers
•Rely on aerobic
respiration
•Adapted for endurance
•Dark in color
•Many mitochondria
•Myoglobin
•Many blood vessels

44. 44
FAST- AND SLOW-TWITCH MUSCLES DIFFER IN
STRUCTURE AND FUNCTION
Figure 13.12 Fast-twitch and slow-twitch muscle fibers differ in structure.

45. 45
EXERCISE PROVIDES A REMARKABLE NUMBER
OF BENEFITS
•Increases muscle
strength, endurance,
and flexibility.
•Increases
cardiorespiratory
endurance.
•HDL increases, thus
improving
cardiovascular health.
•Proportion of protein
to fat increases
favorably.
•Prevent certain cancers:
colon, breast, cervical,
uterine, and ovarian.

•Improves density of
bones, decreasing the
likelihood of osteoporosis.

•Enhances mood and may
relieve depression.

46. 46
ANABOLIC STEROIDS ARE A GROUP OF STEROIDS
THAT USUALLY INCREASE PROTEIN PRODUCTION
•The most common side effects are high blood
pressure, jaundice, acne, and greatly increased risk
of cancer.

•Abuse of these drugs may also cause impotence and
shrinking of the testicles.

•Anabolic steroid use may lead to increased
aggressiveness and violent mood swings.

•Are they worth the risk? Should they be legal to use
in athletics?

47. 47
MUSCLE DISORDERS MAY INVOLVE OVERUSE OR
INJURY
•Spasms – sudden, involuntary
muscle contractions that are
usually painful
•Convulsions (seizures) – multiple
spasms of skeletal muscles
•Cramps – strong, painful spasms
often of the leg and foot
•Strain – stretching or tearing of a
muscle
•Sprain – twisting of a joint
involving muscles, ligaments,
tendons, blood vessels, and
nerves

48. 48
MUSCULAR DISEASES MAY RESULT FROM
INFECTION, CANCER, OR GENETICS
•Fibromyalgia – chronic achy muscles; not well
understood
•Muscular dystrophy – group of genetic disorders in
which muscles progressively degenerate and weaken
•Myasthenia gravis – autoimmune disorder that attacks
the ACh receptor and weakens muscles of the face,
neck, and extremities
•Amyotrophic lateral sclerosis (ALS) – commonly
known as Lou Gehrig’s disease; motor neurons
degenerate and die leading to loss of voluntary
muscle movement
•Sarcomas – cancers that originate in muscle, or the
connective tissue associated with muscle

49. 49
SKELETAL AND MUSCULAR SYSTEMS ARE VITAL
TO HOMEOSTASIS
•Body movement allow us to respond to stimuli,
digest food, return of blood to the heart, and move
air in and out of the lungs.

•Both systems protect body parts.

•Bones store and release calcium needed for
muscle contraction and nerve impulse conduction.

•Blood cells are produced in the bone.

•Muscles help maintain body temperature.

50. 50
THE MUSCULAR SYSTEM INTERACTS WITH OTHER
BODY SYSTEMS TO PROMOTE HOMEOSTASIS

51. 51
THE BIG PICTURE
•Three types of muscle tissue are responsible for
movement within and of the body

•Muscles create motion by sliding filaments using
the energy of ATP

•Muscles are involved with the skeletal system in
homeostasis

•Muscle disorders and diseases may affect all three
muscle types

•Synovial joints allow for movement

52. 52
WHAT HAPPENS WHEN THE SKELETAL SYSTEM IS
COMPROMISED?
Presentation of FOP

•Severe ossification
(transformation into bone)
of fibrous tissue throughout
the body

•Bone grows in the muscle
tissues, tendons, and
ligaments

•The gene is located on
chromosome 2