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KIN 100 > Lower Extremity > Flashcards

Lower Extremity Flashcards

1
Q

What are the 6 functions of the skeletal system?

A

Support, mineral storage, hemopoiesis (red cell production), protection, body movement, and fat and stem cells

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2
Q

What type of bone form the walls?

A

Compact bone

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3
Q

What is the internal layer of bone made of?

A

Spongey bone

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4
Q

What does the medullary cavity contain?

A

Bone marrow - yellow and red marrow and loose connective tissue

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5
Q

How is compact bone arranged?

A

Osetocytes are arranged in circular layers around a central canal which contains blood vessels that supply osteon

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6
Q

How is spongey bone arranged?

A

Arrangement of spongey bone is in struts or thick, branching plates called trabeculae

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7
Q

What is the purpose of osteocytes?

A

To maintain and monitor the protein and mineral count of the surrounding matrix. Each osteocyte directs the release of calcium from bone to blood.

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8
Q

What is the purpose of osteoblasts?

A

They are cuboidal cells found in a single layer on the inner or outer surfaces of a bone. It secretes the organic components of the bone matrix and are responsible for the production of new bone (osteogenesis).

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9
Q

What is the purpose of osteoprogenitor?

A

These cells divide to prodce duaghter cells that differentiate into osteoblasts - stem cells

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10
Q

What is the purpose of osteoclasts?

A

They are large, multinucleate cells found at sites were bone is being removed. Osteoclasts are derived from the same stem cells that produce monocytes and neutrophils (white blood cells). Erosion process, osteolysis, increases the calcium and phosphate concentration in body fluids.

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11
Q

What is periosteum?

A

A layer of compact bone that covers the surface of all bones. The thickness of this layer varies from region to region and from one bone to another

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12
Q

What is the function of periosteum?

A

It isolates and protects bone from surrounding tissues, provides a route and a place of attachment for circulatory and nervous supply, actively participates in bone growth and repair

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13
Q

What is endosteum?

A

A layer inside the bone, a cellular endosteum lines the medullary cavity. It contains osteoprogenitor cells and covers the trabeculae of spongey bone.

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14
Q

What are the functions of the endosteum?

A

Lines the inner surfaces of the central canals and preforating canals. Active during the growth of bone and whenever repairing or remodelling.

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15
Q

What type of elements compose an embryo’s skeletal elements from fertilization to 8 weeks?

A

Either mesenchyme or hyaline cartilage

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16
Q

What is the process called when cartilage or tissues are replaced with bone?

A

Ossification

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17
Q

What is calcification?

A

Refers to the deposition of calcium salts within a tissue

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18
Q

TorF: Any tissue can be calcified, but only ossification forms bone

A

True

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19
Q

What is intramembranous ossification?

A

This is a type of bone ossification in which bone develops from mesenchyme or fibrous connective tissue. The bones that this type of ossification forms include the calvicle, mandible, and flat bones of the face/skull.

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20
Q

What is endochondral ossification?

A

This is a type of bone ossification in which bone replaces an existing cartilage model such as the bones of the limbs and other bones that bear weight

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21
Q

What occurs in the beginning (first step) in the process of endochondral ossification?

A

As the cartilage enlarges, the chondrocytes (cartilage cells) near the centre of the shaft increase greatly in size and the surrounding matrix begins to calcify. The chondrocytes become deprived of nutrients and this causes them to die and disintegrate, leaving cavities within the cartilage.

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22
Q

What occurs in the second step in the process of endochondral ossification?

A

Blood bessels grow around the edges of the catilage and the cells of the perichondrium (fibrous connective tissue that covers surface of cartilage) begin differentiating into osteoblasts. The perichondrium converts into periosteum and a small layer of compact bone develops around the shaft of the cartilage.

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23
Q

What occurs during the third step in the process of endochondral ossification?

A

The blood supply to the periosteum increases, and the capillaries and osteoblasts migrate into the heart of the cartilage, invading the spaces left by the disintegrating chondrocytes. The calcified cartilaginous matrix then breaks down, and osteoblasts replace it with spongey bone.

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24
Q

What occurs during the fourth step in the process of endocondral ossification?

A

While the diameter is small, the entire shaft is filled with spongey bone, but as it enlarges, osteoclasts erode the central portion and create the medullary cavity. The bone shaft becomes thicker and the cartilage of the metaphysis is invaded by osteoblasts that produce columns of bone.

25
Q

What occurs during the fifth step in the process of endochondral ossification?

A

Capillaries and osteoblasts then migrate into the centres of the epiphyses, creating secondary ossification centres.

26
Q

What occurs during the sixth step in the process of endochondral ossification?

A

The epiphyses eventually become filled with spongey bone. The epiphysis and diaphysis are now separated by a narrow epiphyseal cartilage within a metaphysis. Osteoblasts invade the shaft side of the epiphyseal cartilage, replacing the cartilage with bone and enlarges - this enlargement pushes the epiphysis away from the diaphysis, and the length of the bone increases

27
Q

What occurs during the last step in the process of endochondral ossification?

A

At maturity, the rate of epiphyseal cartilage enlargement slows and the rate of osteoblast activity accelerates. As a result, the epiphyseal cartilage gets narrower until it ultimately disappears (epiphyseal closure) and just becomes a physical line. A thin cap of the original cartilage model reamins exposed to the joint cavity as the articular cartilage, preventing damage from bone-to-bone contact within the joint.

28
Q

What is the function and what are the three elements about skeletal muscle tissue?

A

Skeletal muscle tissue moves the body by pulling on the bones of the skeleton. It has voluntary control, striated muscle strands, and it is multi nuclei.

29
Q

What is the function and what are the three elements about cardiac muscle tissue?

A

Cardiac muscle pushes blood through the blood vessels of the CVS. It has involuntary control, striated muscle strands, and has single nuclei.

30
Q

What is the function and what are the three elements about smooth muscle tissue?

A

Smooth muscle pushes fluids and solids along the digestive tract and many other functions. It has involuntary control, non-striated muscle strands, and has single nuclei.

31
Q

What does excitation mean?

A

The ability to respond to stimuli

32
Q

What does contractability mean?

A

Ability to shorten actively

33
Q

What does extensibility mean?

A

The ability to contract over a range of testing length

34
Q

What does elasticity mean?

A

The ability of muscle to return to its original length

35
Q

TorF: Skeletal muscles and smooth muscles both respond to stimulation by the nervous system.

A

False. Although the skeletal system does respond to stimulation by the nervous system, smooth muscle does not. Smooth muscle responds to circulating hormones - this is also because skeletal muscle is voluntary and smooth muscle is involuntary

36
Q

What kind of connective tissue is epimysium?

A

A layer of dense, irregular connective tissue surrounding the entire skeletal muscle. It separates the muscle from surrounding tissues and organs and is connected to deep fascia

37
Q

What kind of connective tissue is perimysium?

A

The connective tissues from perimysium divide the muscle into internal compartments. Each compartment contains a bundle of muscle fibres called a fasicle. They contain collagen, elastic, and numerous blood vessels and nerves supply each fasicle.

38
Q

What kind of connective tissue is endomysium?

A

The endomysium surrounds each skeletal fibre, binds each muscle fibre to its neighbor, and supports capillaries that supply the individual fibre. Scattered myosatelite cells that lie between endomysium and the muscle fibres are stem cells that repair damaged muscle tissue.

39
Q

In a skeletal muscle, the plasma membrane is called what?

A

The sarcolemma

40
Q

Within the sarcolemma is the cytoplasm, which in a muscle cell is called what?

A

The sarcoplasm

41
Q

What causes the conduction of action potentials? What is the purpose of these action potentials?

A

The sarcolemma and T-tubules conduct electrical impulses - called action potentials. The purpose of these are to stimulate muscle fibre contractions.

42
Q

What part of the skeletal muscle fibres are responsible for the contractions?

A

Skeletal muscle fibres contain 100s-1000s of fine cylindrical fibres called myofibrils and the active shortening of these fibres are responsible for the muscle fibre contractions.

43
Q

Myofibrils are made of protein filaments called what? And what is the purpose of them?

A

Myofibrils are made of protein filaments called myofilaments. Each filament contains different types of proteins, each with a specific function during muscle cell contraction and relaxation.

44
Q

What is the main function of the sarcoplasmic reticulum?

A

Surrounding myofibrils is the sarcoplasmic reticulum and the main function of this is a storage and release site of calcium ions. This plays an important role in controlling individual myofibril contractions.

45
Q

What if F-Actin?

A

This is a protein found in thin filaments of a myofibrils. It is a twisted strand composed of globular molecules of G-Actin which is a subunit of the actin molecule. Each molecule of G-Actin contains an active site where myosin and thick filaments can bind.

46
Q

What is nebulin?

A

This is a protein found in thin filaments of myofibrils. It is a slender strand that extends along the F-Actin, holding the F-Actin strand together.

47
Q

What are tropomyosin and troponin?

A

These molecules form a long chain that covers the active sites on G-Actin, preventing actin myosin interaction. Troponin holds the the tropomyosin in place. Before a contraction begins, the troponin molecules must change position moving the tropomyosin molecules, exposing the active sites

48
Q

Describe what a thick filament is composed of and the purpose of it is.

A

Each filament is composed o a bundle of myosin molecules, each made up of a pair of myosin subunits hoisted around one another. There are two components of myosin - a head and a tail. The long tail is bound to the other myosin molecules in the thick filament and the head with two globular protein subunits projects outward toward the nearest thin filament.

49
Q

What is a cross-bridge?

A

When the myosin heads interact with thin-filaments during a contraction

50
Q

What are the physical characteristics of fast muscle fibres?

A

1) Large in diameter
2) Densely packed myofibrils
3) Large glycogen reserves
4) Relatively few mitochondria

51
Q

What are fast muscle fibres?

A

These muscle fibres contract quickly following stimulation. They produce powerful contractions which means they use large amounts of ATP, though with few mitochondria they are unable to meet demand. As a result, contractions are supported by anaerobic metabolism, glycolysis.

52
Q

What is glycolysis?

A

The process of glycolysis is the conversion of stored glycogen to lactic acid.

53
Q

Why do fast fibres fatigue easily?

A

There is a limited amount of mitchondria within the fast muscle fibres which results in less ATP to produce a long-term contraction - fast fibres use a large amount of ATP quickly and with limited supply, it burns out after a short amount of time. These fibres also use anaerobic metabolism called glycolysis. Glycogen reserves are also limited which is what also contributes to fast fatigue.

54
Q

What are the characteristics of slow muscle fibres?

A

1) Smaller diameter of muscle fibres compared to fast fibres
2) Take three times longer to contract after stimulation

55
Q

What are slow muscle fibres?

A

These fibres are specialized to contract for an extended period of time. They fatigue slowly because their mitochondria continue to produce ATP throughout the contraction process. The mitochondria absorb oxygen and generate ATP by a pthway called aerobic metabolsim

56
Q

What two sources allow the required oxygen to be absorbed?

A

1) Skeletal muscle containing slow muscle fibres have a larger netweork of capillaries, meaning there is greater blood flow to the muscle, and red blood cells can deliver more oxygen to the active muscle sites.
2) Contains myoglobin, a globular protein, like hemoglobin, binds oxygen molecules which results slow muscle fibres to contain large oxygen reserves that are mobilized during contraction.

57
Q

What are intermediate fibres?

A

These fibres have properties between those of fast and slow fibres. They contract faster than slow fibres but slower than fast fibres.

58
Q
A

KIN 100 (1 decks)

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