EXAM 4

Question 1

What two types of connective tissue are found in the skeletal system?

Answer 1

The skeletal system consists of two types of connective tissue: bone and the cartilage found at joints

Question 2

What are ligaments?

Answer 2

Ligaments also join the bones.

Question 3

List five functions of the skeleton

Answer 3

The skeleton supports the body, protects soft body parts, produces blood cells, stores minerals and fat, and works with the muscles to permit flexible body movement.

Question 4

Define these structures associated with long bones: diaphysis, epiphysis, periosteum, articular cartilage.

Answer 4

The shaft of a bone is called the diaphysis. It has a large medullary cavity, whose walls are composed of compact bone. The expanded region at the end of a long bone is called an epiphysis. The epiphyses are composed largely of spongy bone that contains red bone marrow. A long bone is covered by the periosteum, except for the articular cartilage on its ends

Question 5

Compare compact bone with spongy bone.

Answer 5

Compact bone is made up of osteons. Bone cells called osteocytes lie in lacunae, tiny chambers arranged in concentric circles around a central canal. Canaliculi run through the matrix of the bone, connecting the lacunae to the central canal. Spongy bone contains plates called trabeculae, the spaces of which are filled with red bone marrow for blood cell production

Question 6

Compare cartilage with bone. Explain the reason that cartilage heals more slowly than bone

Answer 6

Cartilage is weaker and more flexible than bone, and it is slower to heal because of its lack of direct blood supply.

Question 7

Where would the following types of cartilage be found? hyaline cartilage, fibrocartilage, elastic cartilage

Answer 7

Hyaline cartilage has a matrix made of collagen and is found at the ends of long bones and in the nose and trachea. Stronger fibrocartilage has thick rows of collagen fibers and is able to tolerate pressure and tension. Flexible elastic cartilage contains mostly elastin fibers and is found in the external ear and epiglottis. Chondrocytes are cartilage cells that lie within lacunae.

Question 8

What bones make up the axial skeleton?

Answer 8

The axial skeleton lies in the midline of the body and consists of the skull, hyoid bone, vertebral column, and rib cage.

Question 9

What bones make up the skull?

Answer 9

The skull is formed by the cranium and the facial bones.

Question 10

What are fontanels? What causes them to form?

Answer 10

The cranium is made up of eight bones that are incompletely fused in infants, leaving soft spots, or fontanels.

Question 11

What are sinuses? How are they important?

Answer 11

Sinuses are found in the cranium. They reduce the weight of the skull and give resonance to the voice

Question 12

What are the major bones of the cranium?

Answer 12

The major bones of the cranium include the frontal bone, two parietal bones, an occipital bone housing the foramen magnum, two temporal bones, a sphenoid bone, and an ethmoid bone. The sphenoid bone makes up the floor of the cranium. The ethmoid bone helps form the orbits and the nasal septum. In newborns, these bones are joined by fontanels.

Question 13

Describe the following facial bones: frontal bone, mandible, zygomatic bones, maxillae, nasal bones.

Answer 13

The frontal bone of the skull forms the forehead of the face. The lower jaw is made up of the mandible. Zygomatic bones make up the cheekbones, and maxillae form the upper jaw. Two nasal bones form the bridge of the nose.

Question 14

Where is the hyoid bone located and what is its function? What is unique about the hyoid bone?

Answer 14

The hyoid bone is located superior to the larynx, where it anchors the tongue and serves as a point of attachment for the muscles used in swallowing. The hyoid bone is the only bone in the body that does not articulate with another bone.

Question 15

What is the function of the vertebral column?

Answer 15

The vertebral column supports the head and trunk, protects the spinal cord and nerves, and is a site for muscle attachments.

Question 16

What causes scoliosis?

Answer 16

Each vertebra has facets that articulate with each other and spinous processes that project toward the back. Scoliosis is an abnormal (sideways) curvature of the spine.

Question 17

Describe the location of the following types of vertebrae: cervical, thoracic, lumbar, sacral, coccygeal.

Answer 17

Cervical vertebrae are in the neck region and include the atlas and axis. Thoracic vertebrae are in the upper back and have an extra facet for rib attachment. Thick lumbar vertebrae are in the lower back. Five sacral vertebrae fuse to form the sacrum. The coccyx, or tailbone, is composed of four fused vertebrae at the base of the vertebral column.

Question 18

What is the function of intervertebral disks?

Answer 18

Intervertebral disks, formed of fibrocartilage, provide padding between vertebrae. These disks become weak with age and can herniate and rupture.

Question 19

How many pairs of ribs are there? What are floating ribs?

Answer 19

The 12 pairs of ribs all connect to the thoracic vertebrae. The upper seven pairs of ribs connect to the sternum via costal cartilage. The lower two pairs of ribs are “floating ribs” because they are not attached to the sternum.

Question 20

What is the sternum? What is its function?

Answer 20

The sternum (breastbone) lies in the midline of the body and protects the heart and lungs. It is made of the manubrium, the body, and the xiphoid process. The heart is located between the fifth and sixth ribs.

Question 21

What bones make up the appendicular skeleton?

Answer 21

The appendicular skeleton consists of the pectoral and pelvic girdles and their attached limbs.

Question 22

Describe the following bones of the pectoral girdle and upper limbs. Know the locations of these bones.
scapula, clavicle, humerus, radius, ulna, carpals, metacarpals, phalanges

Answer 22

The body has left and right pectoral girdles. The pectoral girdle consists of the scapula (shoulder blade) and the clavicle (collarbone). The glenoid cavity articulates with the head of the humerus, the bone of the upper arm. The radius and ulna make up the lower arm. The hand is made up of eight carpal bones, five metacarpals, and the phalanges of the fingers and thumb.

Question 23

What is an opposable thumb?

Answer 23

An opposable thumb can touch each finger separately or cross the palm to grasp an object.

Question 24

Describe the following bones/structures of the pelvic girdle and lower limbs. Know the locations of these bones/structures. ilium, ischium, pubis, acetabulum, femur, tibia, fibula, patella, tarsals, metatarsals, phalanges.

Answer 24

The pelvic girdle consists of two heavy coxal bones, fused at the sacrum. Each coxal bone is made up of the ilium, ischium, and pubis, all fused at the acetabulum. The thigh contains the femur, and the lower leg is made up of the tibia and fibula. Where the femur articulates with the tibia is the region of the knee and the patella, or kneecap. The ankle contains seven tarsal bones, and five metatarsals make up the arching instep of the foot. Like the bones of the fingers, the bones of the toes are called phalanges.

Question 25

How is the female pelvis different from the male pelvis?

Answer 25

The male pelvis and the female pelvis differ somewhat due to their different functions. The female pelvis is more flared.

Question 26

Describe the following articulations (joints) and give example of each: fibrous joints, cartilaginous joints synovial joints.

Answer 26

Bones are joined at the joints, which are classified as fibrous, cartilaginous, or synovial. Fibrous joints are immovable. Cartilaginous joints are connected by hyaline cartilage and tend to be slightly movable. Synovial joints are freely movable. In a synovial joint, there is a fibrous joint capsule lined with synovial membrane. Fluid-filled sacs called bursae reduce friction, and menisci add stability.

Question 27

Define the following terms related to movement: flexion, extension, abduction, adduction, supination, pronation, rotation, circumduction, inversion, eversion.

Answer 27

Synovial joint movements include flexion, extension, abduction, adduction, supination, pronation, rotation, circumduction, inversion, and eversion.

Question 28

When does the skeleton start to form? Bones continue to grow in length and width through what period?

Answer 28

The skeleton starts to form at six weeks. Bones grow in length and width through adolescence. Bones are living tissues.

Question 29

What are the functions of the following bone cells? osteoblasts, osteocytes, osteoclasts

Answer 29

Osteoblasts are bone-forming cells. Osteocytes are mature bone cells arising from osteoblasts. Osteoclasts are bone-absorbing cells.

Question 30

Define: ossification.

Answer 30

Ossification refers to the formation of bone.

Question 31

What are epiphyseal plates or growth plates? Where are they found? When do they close in women and in men?

Answer 31

The epiphyses of long bones continue to grow from a growth plate.
Final Size of the Bones
When the epiphyseal plates close, bones can no longer increase in length. In women, this happens at about age 16 to 18 and in men, at about age 20.

Question 32

How do Vitamin D and growth hormone affect bone growth? How do sex hormones affect bone growth?

Answer 32

Vitamin D and growth hormone (GH) affect the growth of the bones. Too little growth hormone in childhood results in dwarfism. Adolescents experience a growth spurt due to increased sex hormones.

Question 33

How is bone recycling important? How is bone remodeling important?

Answer 33

In adults, the actions of osteoclasts and osteoblasts continually remodel bones. Bone recycling allows the body to regulate the amount of calcium in the blood. Bone remodeling also accounts for why bones can respond to stress.

Question 34

What is the action of parathyroid hormone? What is the action of calcitonin?

Answer 34

Parathyroid hormone (PTH) stimulates osteoclasts to dissolve the calcium matrix of bone. Calcitonin has the opposite effect.

Question 35

What is the main cause of osteoporosis in older women?

Answer 35

The reduction of estrogen in older women causes osteoporosis.

Question 36

Describe the process of bone repair.

Answer 36

About six to eight hours after a fracture, a hematoma (large blood clot) forms at the fracture site. A fibrocartilage callus fills in the break. A bony callus formed by osteoblasts replaces the cartilage and lasts about three to four months. Osteoclasts eventually remodel the bone, building a new medullary cavity. Fractures are named according to the type of break (e.g., spiral).

Question 37

Compare yellow bone marrow with red bone marrow. What are their functions?

Answer 37

The skeletal bones contain two types of marrow: yellow and red. Fat is stored in yellow marrow as an energy reserve. Red bone marrow is where blood cells are produced, both red and white. White blood cells defend against pathogens.

Question 38

Describe the characteristics and locations of the following types of muscles: smooth, cardiac, skeletal.

Answer 38

Smooth muscle fibers are spindle-shaped cells, each with a single nucleus. There are no striations. Contraction of smooth muscle is involuntary. Smooth muscle is located in the walls of hollow organs and blood vessels. Cardiac muscle forms the heart wall. Its fibers are generally uninucleated, striated, tubular, and branched. Cardiac fibers relax completely between contractions, which prevents fatigue. Intercalated disks connect cardiac muscle cells. Skeletal muscle fibers are tubular, multinucleated, and striated. Skeletal muscle contraction is voluntary. Fibers run the length of the muscle.

Question 39

List six different functions of skeletal muscles.

Answer 39

Skeletal muscles support the body, make bones move, help maintain a constant body temperature, assist movement of fluids in cardiovascular and lymphatic vessels, and help protect internal organs and stabilize joints.

Question 40

What is a fascicle? What is fascia?

Answer 40

A whole muscle contains bundles of skeletal muscle fibers called fascicles. Within a fascicle, each fiber is surrounded by connective tissue, and the fascicle itself is also surrounded by connective tissue.Muscles are covered with fascia, a type of connective tissue that extends beyond the muscle and becomes its tendon, anchoring the muscle to the bone.

Question 41

What is the difference between the origin of a muscle and the insertion of a muscle?

Answer 41

The origin of a muscle is the end attaching to the immovable bone; the insertion of a muscle is the end attaching to the movable bone.

Question 42

What are synergists? What is their relationship to muscles known as agonists? (p. 244 in text)

Answer 42

Muscles are frequently grouped as synergists and antagonists. One muscle, the agonist, or prime mover, does most of the work for any particular movement.

Question 43

What are antagonists? (p. 244 in text)

Answer 43

Muscles are frequently grouped as synergists and antagonists. One muscle, the agonist, or prime mover, does most of the work for any particular movement.

Question 44

How are muscles named? (examples on p. 245 in text)

Answer 44

Skeletal muscles are named according to their size, shape, location, direction of fibers, attachment, number of attachments, or action.

Question 45

What gives skeletal muscle a striated (striped) appearance?

Answer 45

The alternating dark and light bands give skeletal muscle a striated appearance.

Question 46

Define: sarcolemma, sarcoplasmic reticulum. What is the function of the sarcoplasmic reticulum?

Answer 46

The plasma membrane of a muscle fiber is its sarcolemma. Its endoplasmic reticulum is called the sarcoplasmic reticulum, which stores calcium. The sarcolemma invaginates into T tubules that contact the sarcoplasmic reticulum.

Question 47

What type of ions are needed for muscle contraction?

Answer 47

Calcium ions (Ca2+) are needed for muscle contraction. Within muscle fibers are the contractile myofibrils.

Question 48

Describe the structure of a skeletal muscle fiber. Know the relationship among the sarcolemma, sarcoplasmic reticulum, sarcoplasm, T tubules, myoglobin, myofibrils, and myofilaments of actin and myosin. (See Table 13.1 on p. 247 and Figure 13.6 on p. 248 in text)

Answer 48

Myofibrils are cylindrical structures within muscle fibers. Myofilaments that make up myofibrils are arranged such that they exhibit striations. Striations are grouped into contractile units called sarcomeres. Within sarcomeres, thick filaments are made up of myosin, and thin filaments are made up of actin.

Question 49

Briefly describe the sliding filament model of muscle contraction.

Answer 49

When a nervous impulse reaches a muscle fiber, the sarcoplasmic reticulum releases its stored calcium, and the fiber contracts. The myosin filaments have cross-bridges that pull on the actin filaments, causing them to slide past each other. The sliding filament model shows that the filaments do not change in length as the sarcomere shortens.

Question 50

What is a neuromuscular junction?

Answer 50

The region where a motor neuron contracts a muscle fiber is called the neuromuscular junction.

Question 51

What is a motor unit? How do they operate?

Answer 51

A nerve fiber, together with all of the muscle fibers it innervates, is called a motor unit. A motor unit obeys the all-or-none law.

Question 52

What is occurring with a muscle when it has good muscle tone?

Answer 52

When some motor units are always contracted but not enough to cause movement, the muscle is firm and solid. It has good tone.

Question 53

Compare muscle twitch with tetanus. What is recruitment?

Answer 53

When a motor unit is stimulated by infrequent electrical impulses, a single contraction occurs that lasts only a fraction of a second. This response is called a muscle twitch. If a motor unit is given a rapid series of stimuli, it can respond to the next stimulus without relaxing completely. Summation is increased muscle contraction until maximal sustained contraction, called tetanus, is achieved. As the intensity of nervous stimulation increases, more motor units of a muscle are activated. This is known as recruitment. At any one time, some motor units contract maximally, while others rest.

Question 54

What are the four possible energy sources for muscles?

Answer 54

A muscle has four possible energy sources. Two of these are stored in muscle: glycogen and fat. Two of these are acquired from blood: glucose and plasma fatty acids.

Question 55

What are the three sources for ATP for muscle contraction?

Answer 55

The Creatine Phosphate Pathway
The simplest and fastest way for muscles to produce ATP is to use the CP pathway. Creatine phosphate is converted to creatine with the conversion of ADP to ATP.
Fermentation
Fermentation produces two ATP molecules from the breakdown of glucose to lactate anaerobically. This pathway most likely begins with glycogen. Formation of lactate is noticeable because it produces muscle aches and fatigue upon exercising.
Cellular Respiration
Cellular respiration is the slowest and most efficient way to produce ATP. It is more likely to supply ATP when exercise is submaximal in intensity. It can make use of glucose from the breakdown of glycogen stored in muscle, glucose taken up from blood, and fatty acids.

Question 56

What are the characteristics of fast-twitch fibers?

Answer 56

Fast-twitch fibers tend to be anaerobic and seem to be designed for strength because their motor units contain many fibers. They are light in color because they have fewer mitochondria, little or no myoglobin, and fewer blood vessels than slow-twitch fibers. They depend on anaerobic energy, causing them to accumulate lactate and to tire easily.

Question 57

What are the characteristics of slow twitch fibers?

Answer 57

Slow-twitch fibers have a steadier tug and more endurance despite having more units with smaller numbers of fibers. These fibers produce most of their energy aerobically. They have many mitochondria and are dark in color because they contain myoglobin. They contain a reserve of glycogen and fat for a prolonged production of ATP in the presence of oxygen.

Question 58

Define the following common muscle conditions: spasm, cramp, strain, sprain, tendonitis, bursitis.

Answer 58

Spasms are involuntary muscle contractions that may cause pain. Cramps are long, painful spasms. A strain is an overstretching of a muscle; a sprain is a twisting of a joint leading to swelling and injury, not only of muscles but also of ligaments, tendons, blood vessels, and nerves. In tendonitis, the normal gliding motion of a tendon is impaired, the tendon is inflamed, and movement of a joint becomes painful. Bursitis is an inflammation of a bursa.

Question 59

Compare myalgia with fibromyalgia.

Answer 59

Myalgia refers to achy muscles. Fibromyalgia is a chronic condition, the cause of which is unknown, whose symptoms include achy pain and tenderness and stiffness of muscles.

Question 60

What are the basic characteristics of the following muscular diseases? muscular dystrophy, myasthenia gravis, muscle cancer

Answer 60

Muscular Dystrophy
Muscular dystrophy is a broad term applied to a group of disorders that are characterized by a progressive degeneration and weakening of muscles. Duchenne muscular dystrophy, caused by the lack of a protein called dystrophin, is a disorder linked to the X chromosome.
Myasthenia Gravis
Myasthenia gravis is an autoimmune disease characterized by muscle weakness. The immune system mistakenly produces antibodies that destroy acetylcholine receptors.
Muscle Cancer
Cancers that originate in muscle or the connective tissue associated with muscle belong to a group called soft tissue sarcomas, which may occur in both smooth and skeletal muscles. Rhabdomyosarcoma is an example of a cancer that originates in the skeletal muscle.

Question 61

How do the muscular system and skeletal system contribute to homeostasis?

Answer 61

Both the muscular and skeletal systems contribute to homeostasis, often working together in order to do so.
Both Systems Produce Movement
The skeletal and muscular systems work together to enable body movement.
Both Systems Protect Body Parts
The skeletal system plays an important role just by protecting the soft internal organs of the body. The muscular system pads bones, and the tendons and bursae reinforce and cushion joints.
Muscles Help Maintain Body Temperature
The muscular system contributes to body temperature.