Skeleton/Muscles/Exercise Physiology

Skeleton

rigid body support with muscles attached

Hydrostatic skeleton

fluid or air held under pressure in a closed body compartment (ex. earthworm)

Exoskeleton

a hard skeleton on the outside of the body (ex. Arthropods, Nematode worms)

Endoskeleton

a hard skeleton on the inside of the body (ex. sponges, starfish, chordates)

Cartilage is made from…

collagen (protein) fibers

Bones are made from…

collagen strengthened by calcium phosphate

Spongy bone

honeycomb-like network of bony trabeculae with spaces from blood vessels and marrow

*found in the interior of bones

Compact bone

dense, compacted layer of bone forming the hard outer layer

Functions of bones

• movement

• protect internal organs

• store calcium and phosphorus

• red/white stem cells in bone marrow

Osteoclasts

cells that secrete acids and constantly remove bone

Osteoblasts

cells that build bone

Bone marrow

produces red and white blood cells and stores some fat

Bone fracture

cracked or broken bone

Stress fracture

hairline fracture

Compound fracture

broken bone pierces skin

Axial skeleton

includes skull, vertebral column, and thorax

Appendicular skeleton

includes upper and lower extremities

How to identify a juvenile skull?

dental development

How to identify a adult skull?

cranial structure and other degenerative changes associated with aging

Female pelvis

• oval shaped pelvic opening

• wider pelvic outlet

• pubic arch greater then 90 degrees

Male pelvis

• narrower

• smaller pelvic opening

• pubic arch less than 90 degrees

A human’s height is ___ times their femur length

four

Histology

microscopic study of tissues

Muscle fiber

a single, long muscle cell

Muscle

a bundle of fascicles

Fascicle

a bundle of muscle fibers

Epimysium

connective tissue around muscle

Tendon

extension of epimysium that connects muscle to bone

Smooth muscle

involuntary, not striated muscle found in the walls of vessels (control diameter), the intestines (peristalsis), and the stomach (churning food and vomiting)

Cardiac muscle

involuntary, straited muscle found only in the heart

Skeletal muscle

voluntary, striated muscles attached to bones for movement

Origin (muscles)

point of attachment to the bone that doesn’t move

Insertion (muscles)

point of attachment to the bone that bends

Skeletal muscles work in __________ pairs

antagonistic

Agonist

muscle responsible for specific movement

Antagonist

muscle that opposes agonist movement

Flexion

decreases the angle between body parts (ex. bending elbow, contracting bicep)

Extension

increases angle between body parts (ex. straightening elbow, contracting triceps)

Why are there different types of muscle fibers?

different cell types = different performance

Fast-twitch Glycolytic (FG)

• white

• little myoglobin and mitochondria

• explosive speed, no endurance

• anaerobic

Slow-twitch Oxidative (SO)

• red

• more mitochondria and myoglobin

• slow speed, good endurance

• aerobic

Fast Oxidative-Glycolytic (FOG)

• pink

• intermediate between SO and FG

Exercise physiology

exercise makes muscle fibers bigger or more resistant to fatigue

Endurance training

• light weights, many reps

• increases mitochondria/capillaries in muscle to bring oxygen for aerobic respiration

Strength training

• heavy weights, few reps

• muscles thicker because more actin/myosin protein

• increases enzymes used in glycolysis

• burn sugars, not fats

Tuna muscle fiber type

SO - swim constantly

Flounder muscle fiber type

FG - wait at bottom of ocean and sprint around

Swordfish muscle fiber type

SO and FG - swimming all the time but sprint to hunt