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Flashcards in Skeletal and Muscular System Deck (62):
1

Endoskeleton

-serves as the framework with in all vertebrate organisms
-provides protection by surrounding internal organs with bone
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2

what does the rib cage protect?

protects the thoracic organs (lungs and heart)

3

What does the skull protect?

the brain

4

What does the vertebral column protect?

spinal chord

5

what are the two main components of the endoskeleton?

cartilage and bone

6

Cartilage

a type of connective tissue that is softer and more flexible than bone
-retained in adults in places where firmness and flexibility are needed

7

What contains cartilage on humans?

external ear, nose, walls of the larynx and trachea, and skeletal joints

8

Chrondocytes

cells responsible for synthesizing cartilage

9

Bone

specialized type of mineralized connect tissue that has the ability to withstand physical stress
-bone is adapted for body support
-bone tissue is hard and strong while lightweight and elastic

10

What are the two basic types of bones?

compact and spongy

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compact bones

-is dense bone that does not appear to have any cavities when observed with the naked eye
-the bony matrix is deposited into structural units called OSTEONS

12

Osteons

-consists of a central microscopic channel called Hervesian canal, surrounded by a number of concentric circles of boney matrix called LAMALLE

13

Spongy Bone

-much less dense and consist of an interconnecting lattice of bony spicules

14

Yellow marrow of spongy bone

is inactive and infiltrated by adipose tissue

15

Red Marrow of spongy bone

is involved in blood cell formation

16

what are Osteocytes and the two kinds

osteocytes are a type of cell found in bone tissue
-Osteoblasts
-osteoclasts

17

osteoblasts

synthesize and secrete the organic material of the bone matrix
-once they have become surrounded by their matrix they mature into osterocytes

18

Osteoclasts

large, multinucleate cells involved in bone reabsorption
-where bone is broken down and minerals are released into the blood

19

Bone Formation

occurs by either endochondral ossification or intramembranous ossification

20

endochondral ossification

-existing cartilage is replaced by bone
-large bones primarily form

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Intramembranous Ossification

-messenchymal (embryonic or undifferentiated) connective tissue is transformed into and replaced by bone

22

Axial Skeleton

basic framework of the body
-consists of the skull, vertebral column, and rib cage

23

Appendicular Skeleton

point of attachment
-includes the bonds of the appendages (limbs) and the pectoral and pelvic girdles

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Ligaments

bone to bone connectors

25

Tendons

attach skeletal muscles to bones
-bend the skeleton at moveable joints

26

What holds the bones of the skull together?

sutures or immovable joints

27

Origin

the point of attachment to a stationary bone
-ex: proximal end and limb muscles

28

insertion

the point of attachment of a muscle to a bone that moves

29

extension

indicates the straightening of a joint

30

Flexion

refers to the bending of a joint

31

What does muscle tissue consist of?

consists of bundles of specialized contractive fibers held together by connective tissue

32

What are the different types of muscles?

skeletal muscle
smooth muscle
cardia muscles

33

Skeletal muscles

responsible for voluntary movements and is innervated by the somatic nervous system
-has striations of light and dark bands reffered to as STRIATED BANDS

34

What is embedded in the muscle fibers?

filaments called MYOFIBRILS

35

What are myofibrils further divided into?

contractile vacuoles called SACROMERES

36

Sacroplasmic Reticulum

envelope the myofibrils
-is a modified endoplasmic reticulum that stores calcium ions

37

Sarcoplasm

the cytoplasm of a muscle fiber

38

Sarcolemma

cell membrane of a muscle fiber
-capable of making an action potential
-is connectd to a system of transverse tubules (T-system)

39

T-systems

provides channels for ion flow throughout the muscle fibers
-can make an action potential

40

Sacromeres

composed of thin and thick filaments
-the thin filaments are chains of actin molecules
-the thick filaments are organized bundles of myosin molecules

41

Z lines

-defines the boundaries of a signal sacromere
-anchor the thin filaments

-during contraction the Z lines move toward each other

42

M line

runs down the center of the sacromere

43

I Band

region containing the thin filaments ONLY of the sacromere
-Reduced in size when contraction occurs

44

H zone

region containing thick filaments only of the sacromere
-reduced in size when contraction occurs

45

A band

spans the entire length of the thick filament and any overlapping portions of the thin filaments
-DOES NOT reduce in size when contraction occurs

46

Contraction

stimulated by a message from the somatic nervous system sent via a motor neuron

47

Neuromuscular junction

link between the nerve terminal and the sacrollema of the muscle fiber

48

Synapse/Synaptic Cleft

is in-between the neuromuscular junction and sacrollema

49

Rigor Mortis

after death our muscles go into this state
-our muscles contract and become rigid, even without action potentials

50

What are the 5 major types of muscle contractions?

1. isotonic
2. dynamic
3. concentric
4. eccentric
5. Isometric

51

Isotonic muscle contractions

contraction occurs when a muscle shortens against a fixed load while the tension on that muscle remains constant

52

Dynamic Muscle contraction

includes both concentric and eccentric types of contraction
-results in the change in length of the muscle with a corresponding change of tension on the mucles

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concentric muscle contraction

a type of dynamic contraction
-the muscle fibers shortens and the tension on the muscle increases

54

Eccentric muscle contraction

contraction is a type of dynamic contraction of the muscles -the muscle fibers lengthen and then tension of the muscles increases

55

Isometric muscle contraction

contraction occurs when both ends o the muscle are fixed and no change in length occurs during contraction, BUT THE TENSION INCREASES

56

What elicits a contraction?

muscles exhibit an all or none response
-ONLY a stimulus above a minimum (THRESHOLD VALUE) can elicit a contraction

57

How can you increase the strength of contraction of a single muscle fiber?

CANT regardless of the strength of the stimuli

58

HOw can you increase the strength of contraction of entire muscle?

can be done
-can increase strength by recruiting more muscle fibers

59

Simple twitch

muscle response
-response of a single muscle fiber to a brief stimulus at or above the threshold value
-consists of a latent period, contraction period, and relaxation period

60

what is the latent period of simple twitch

is the time between stimulation and the onset of contraction
-the action potential spreads along the sacrollema and Ca2+ ions are released

61

Absolute refractory period

after the contraction period there is a brief relaxation period during which the muscle is unresponsive to a stimulus

62

Temporal stimulation

?