Muscloskeletal System

Front 1

5 primary functions of the skeleton?

Back 1

1) support
2) protection
3) movement
4) storage
5) blood cell production

Front 2

rigid, strong bone

Back 2

well suited for bearing weight
the major supporting tissue of the body

Front 3

function of cartilage?

Back 3

provides a firm, yet flexible support within certain structures (nose, external ear, rib cartilages, trachea)

Front 4

What are ligaments?

Back 4

strong bands of fibrous connective tissue that attach to bones and hold them together

Front 5

What three things include in support system of the skeleton?

Back 5

1) rigid, strong bone
2) cartilage
3) ligaments

Front 6

bone : protenction

Back 6

bone is hard and protects the organs it surrounds

Front 7

skull

Back 7

encloses and protects the brain

Front 8

vertebrae

Back 8

surround the spinal cord

Front 9

rib cage

Back 9

protects the heart, lungs, and other organs of the thorax

Front 10

What are the four things importnat in the skletal movement?

Back 10

1) skeletal muscles
2) joints
3) smooth cartilage
4) ligaments

Front 11

skeletal muscles

Back 11

attach to bones by tendons

Front 12

tendons

Back 12

strong bands of connective tissue

Front 13

contraction of the skeletal muscle

Back 13

moves the bones, producing body movements

Front 14

Where are joints formed?

Back 14

where two or more bones come together

Front 15

function of joints?

Back 15

permit and control the movement between bones

Front 16

smooth cartilage

Back 16

covers the ends of bones within some joints, allowing the bones to move freely

Front 17

function of ligaments?

Back 17

allow some movement between bones but prevent excessive movements

Front 18

What are two principle minerals stored into bone?

Back 18

calcium and phosphorus

Front 19

Where is fat (adipose tissue) stored?

Back 19

within bone cavities

Front 20

many bones contain cavities filled with?

Back 20

bone marrow

Front 21

bone marrow gives rise to?

Back 21

blood cells and platelets

Front 22

three types of bone cells?

Back 22

1) osteoblasts
2) osteocytes
3) osteoclasts

Front 23

What are osteoblasts?

Back 23

bone-forming cells

Front 24

primary function of osteoblasts?

Back 24

to lay down new bone

Front 25

after forming new bone, osteoblsats become what?

Back 25

osteocytes

Front 26

What does an osteoblast produce?

Back 26

type one collagen & osteocalcin

Front 27

type I collagen is responsive to?

Back 27

PTH (parathyroid hormone)

Front 28

When osteoblasts produce osteocalcin?

Back 28

when stiumulated by 1,25-dyhydroxyvitamin D

Front 29

osteocalcin

Back 29

a calcium-binding protein
inhibit Ca-Phosphate precipitation
promotes bone resorption

Front 30

osteoblasts are active on?

Back 30

on the outer surface of bones, where they form a SINGLE layer of cells

Front 31

osteoblasts bring about the formation of new bone by?

Back 31

by their synthesis of OSTEOID (non-mineralized bone matrix)

Front 32

What is osteoid?

Back 32

a protein mixture composed mainly of collagen that is secreted by osteoblasts and becomes mineralized to form bone

Front 33

What are osteocytes?

Back 33

are osteoblasts that have become imprisoned within the mineralized bone matrix

Front 34

function of osteocytes?

Back 34

help maintain bone by synthesizing new bone matrix molecules

Front 35

function of osteocytes? #2

Back 35

not fully known
synthesize certain matrix molecules assisting bone calcification

Front 36

osteocytes : nutrients

Back 36

osteocytes obtain nutrients from capillaries in the CANALICULI
help concentrate them in the matrix
help synthesize and replace needed elements of the matrix

Front 37

obtaining nutrients from calillaries in the canaliculi help what?

Back 37

help to maintain mineral homeostasis with the help of the PTH and osteoblast cells

Front 38

definition of osteocyte?

Back 38

is a transformed osteoblast that is trapped or surrounded in OSTEOID as it hardens from minerals that enter during calcification

Front 39

What are osteoclasts?

Back 39

the major resorptive cells of bone
large, multinucleated cells
short life span

Front 40

osteoclasts develop from?

Back 40

1)from the hematopoietic stem cells in the bone marrow stroma and adjacent vessels
2) from mononuclear phagocytic cells

Front 41

function of osteoclasts?

Back 41

to resorb (remove) bone during of growth and repair

Front 42

osteoclasts contain what?

Back 42

lysosomes (digestive vacuoles) filled with hydrolytic enzymes

Front 43

long bone

Back 43

femur
thigh bone
humerus of arm

Front 44

flat bone

Back 44

parietal bone of skull

Front 45

short bone

Back 45

carpals of wrist
wrist bone

Front 46

irregular bone

Back 46

sphenoid bone from skull
vertebra

Front 47

muscle

Back 47

consists of hundreds to thousands of muscle cells, plus connective tissue wrappings, blood vessels, and nerve fibers

Front 48

muscle are covered externally by?

Back 48

the epimysium

Front 49

fascicle

Back 49

discrete bundle of muscle cells, segregated from the rest of the muscle by a connective tissue sheath

Front 50

fascicle are surrounded by?

Back 50

perimysium

Front 51

muscle fiber

Back 51

elongated multinucleate cell; has a banded (striated) appearance

Front 52

muscle fiber are surrounded by?

Back 52

endomysium

Front 53

motor units are composed of what?

Back 53

lower motor neurons, which extend to skeletal muscles

Front 54

another name for motor unit?

Back 54

the functional unit of the neuromuscular system

Front 55

motor unit behaves as?

Back 55

a single entity and contracts as a whole when it receives an electrical impulse

Front 56

whole muscle may be controlled by?

Back 56

several motor nerve axones, which innervate many motor units within the muscle

Front 57

Does the # of motor units per individual muscle vary?

Back 57

varies greatly
(Ex) Calf - one motor axon will innervate appro. 2000 muscle fibers, out of a total of 1,200,000 muscle fibers

Front 58

2 types of muscle contraction

Back 58

1) isometric contraction
2) isotonic contraction

Front 59

isometric contraction

Back 59

static or holding contraction
the muscle maintains constant length as tension is increased

Front 60

example of isometric contraction

Back 60

when the arm or leg is pushed against an immovable object
the muscle contracts, but the limb does not move

Front 61

isotonic contraction

Back 61

the muscle maintains a constant tension as it moves

Front 62

2 types of isotonic contractions

Back 62

1) eccentric (lengthening)
2) concentric (shortening)

Front 63

eccentric isotonic contraction

Back 63

the muscle lengthens and absorbes energy

Front 64

concentric isotonic concentration

Back 64

positive work is accomplished
energy is released to exert force or lift a weight

Front 65

Do actin and myosin myofillaments change length during contraction of skeletal muscle fibers?

Back 65

NO! Instead, actin and myosin myofillaments slide past one another in a way that causes the sarcomeres to shoten.

Front 66

Whar happens during contraction?

Back 66

1) actin myofillaments at each end of the sarcomere slide past the myosin myofilaments toward the H zone
2) I bands shorten
3) A bands do not chenge

Front 67

H zone during the contraction?

Back 67

the H zone narrows or even disappears as the actin myofilaments meet at the center of the sarcomere

Front 68

the last step of contraction

Back 68

as the actin myofilaments slide over the myosin myofilaments, the Z disks are brought closer together, and the sarcomere is shortened

Front 69

contracting muscle

Back 69

1) sarcomere shortens
2) actin myofilaments move toward H zone

Front 70

fully contracted muscle

Back 70

sarcomere is shortened but A band width is unchanged