2. Structural Support and Movement
Chapter 37

3. Hydrostatic Skeleton
Muscles work against an internal body fluid and redistribute it within a confined space
Radial cells are relaxed; longitudinal ones contracted
Radial cells are contracted; longitudinal ones relaxed

4. Exoskeleton
Fly wing action

5. Echinoderms Echinoderms have endoskeletons located within their dermis
tube foot
ossicle

6. Endoskeleton All vertebrates
Fins or limbs attach to skeleton at pectoral and pelvic girdles
Generalized mammal
pelvic girdle
pectoral girdle

7. Vertebrate Skeletons
Vertebrate skeletons

8. SKULL
PECTORAL GIRDLES
AND UPPER EXTREMITIES
cranial bones
facial bones
clavicle
RIB CAGE
scapula
sternum
ribs
humerus
radius
VERTEBRAL COLUMN
ulna
vertebrae
phalanges
intervertebral disks
carpals
metacarpals
PELVIC GIRDLE AND
LOWER EXTREMITIES
pelvic girdle
femur
patella
tibia
fibula
tarsals
phalanges
metatarsals

9. Functions of Bone interact with muscle to enable movement
support and anchor muscles
enclose and protect internal organs
store minerals
calcium
phosphorus
produce blood cells
red bone marrow
blood cells, platelets

10. Functions of Bone yellow bone marrow mostly fat
fills cavities of adult long bones
can be converted into red bone marrow
times of severe blood loss

12. Bone Growth / Renewal
adjusts bone strength and helps maintain Ca levels
osteoblasts
osteoclasts
compact bone
resists mechanical shock
spongy bone
pockets with open spaces
often filled with red bone marrow

13. Bone Structure
Long bone formation

14. Bone Structure
Structure of a femur

15. Bone Density Exercise can increase bone density
Osteoporosis is a decrease in bone density
May occur when the action of osteoclasts outpaces that of osteoblasts
May also occur as a result of inability to absorb calcium

16. Bone Density

17. Bone Density

18. Joints areas of contact or near contact between bones 3 types
fibrous joints
exist between cranial bones
immovable

19. Joints
cartilaginous joints
between vertebrae
slightly moveable

20. Joints synovial movable joints ligaments connect bone to bone
osteoarthritis
cartilage wears away
rheumatoid arthritis
joint members become inflamed

21. Tendons Attach Muscle to Bone
bursae
synovial
cavity

22. Impacts, Issues Video
Pumping Up Muscles

23. Muscle contraction overview

24. Muscles 3 types smooth cardiac skeletal maintains posture
allows movement
maintains body temperature
provide joint stability
contraction of muscle causes ATP breakdown

25. Skeletal Muscle Structure
Structure of skeletal muscle

26. Skeletal Muscle Structure
A muscle is made up of muscle cells
A muscle fiber is a single muscle cell
Each fiber contains many myofibrils
myofibril

27. Structure of a sarcomere

28. Muscles components sarcolemma cell membrane of muscle cell
sarcoplamsic reticulum
stores Ca
essential for muscle contraction
myofibrils
have striations
formed by units called sarcomeres
myosin
actin

29. Muscle Microfilaments
thin filaments
like two strands of pearls twisted together
pearls are actin
other proteins in grooves in filament
thick filaments
composed of myosin
each myosin molecule has tail and a double head

30. Muscles sliding filament model controlled by troponin and tropomyosin
actin filaments slide past mysoin
sarcomeres shorten

31. Nervous System Controls Contraction
Signals from nervous system travel along spinal cord, down a motor neuron
Endings of motor neuron synapse on a muscle cell at a neuromuscular junction

33. Neuromuscular Junction
Axon terminal fits into depression in sarcolemma
Nerve impulse travels down axon to axon terminal
ACH is released into synaptic cleft and binds with receptor sites
Travels into T-tubules which cause Ca to be released from sarcoplasmic reticulum
Ca alters the configuration of actin and causes a change in binding site on actin

34. Troponin and Tropomyosin
lie in groove in actin filament
when muscle is relaxed, tropomyosin blocks myosin binding site
myosin
binding site
blocked
troponin
actin

35. Troponin and Tropomyosin
when troponin binds calcium ions, it changes shape and moves tropomyosin
cross-bridge formation and contraction can now proceed
myosin head
actin

36. Troponin and Tropomyosin

37. Neuromuscular Junction
Ach
contraction
activates release of Ca
Ache
relaxation
recyles Ach
causes Ca to be reabsorbed into sarcoplasmic reticulum

39. Sliding filament model
Muscle Contraction
Sliding filament model

40. Contraction Requires Energy
muscle cells require huge amounts of ATP energy to power contraction
the cells have only a very small store of ATP
three pathways supply ATP to power muscle contraction

41. Energy sources for contraction
ATP for Contraction
Energy sources for contraction

42. Energy Pathways creatine phosphate storage form gets things started
donates a phosphate to APD
aerobic Respiration
primary source
produces 20 times the ATP
takes longer to produce
anaerobic Respiration
produces ATP faster than aerobic
cost  build up of lactic acid

44. ATP for Contraction Dephosphorylation Creatine Phosphate Aerobic
ADP + Pi
Pathway 1
Dephosphorylation
Creatine Phosphate
relaxation
contraction
creatine
Pathway 2
Aerobic
Respiration
Pathway 3
Glycolysis
Alone
glucose from bloodstream and from glycogen break down in cells
oxygen

46. Motor Unit
one neuron and all the muscle cells that form junctions with its endings
when a motor neuron is stimulated, all the muscle cells it supplies are activated to contract simultaneously
each muscle consists of many motor units

47. Muscle Contractions
Types of contractions

48. Muscle Fatigue An inability to maintain muscle tension
Occurs after a period of tetanic contraction
Different types of muscle show different fatigue patterns