Muscular and Skeletal Systems

Question 1

The musculoskeletal system forms the basic __ __ of the vertebrate body. Muscles and bones work in close coordination to produce ___ __. In addition, they perform a number of other ____ functions. Physical support and ___ are the function are the functions of the animal skeletal system, while the muscular system generates ____

Answer 1

internal framework, voluntary movement, independent, locomotion, force

Question 2

An ____ serves as a framework in all vertebrate organisms. Muscles are attached to the bones, permitting _____. The endoskeleton also provides ___ by surrounding delicate ___ __ with bone. The ___ ___ protects the thoratic organs like the ___ and lungs. The ___ and the ___ __ protect the brain and spinal cord. The two major components of the skeleton are ___ and ____

Answer 2

endoskeleton, movement, protection, internal organs, rib cage, heart, skull, vertebrate column, cartilage, bone

Question 3

Cartilage is a type of connective tissue that is ___ and more ___ than bone. Cartilage is retained in adults where ____ and ____ are needed. In humans, the ___ ___, nose, walls of the ____ and ____, and ___ ___ contain cartilage.

Answer 3

softer, flexible, firmness, flexibility, external ear, larynx, trachea, skeletal joints

Question 4

Cells responsible for synthesizing cartilage

Answer 4

chrondrocytes

Question 5

Bone is a specialized type of ______ connective tissue that has the ability to withstand ___ ____. Ideally adapted for ___ ___, bone tissue is hard and ___, while at the same time somewhat ___ and lightweight. There are two basic types of bone, ____ bone and ____ bone

Answer 5

mineralized, physical stress, physical support, strong, elastic, compact, spongy

Question 6

Compact bone is a ___ bone that does not appear to have any ____ when observed with the naked eye. The bone matrix is deposited in structural units called _____ (____ systems). Each one consists of a central microscopic channel called a ___ ___, surrounded by a number of concentric circles of bony matrix (____ ___) called ____.

Answer 6

dense, cavities, osteons, haversian systems, haversian canal, calcium phosphate, lamellae

Question 7

Spongy bone is much less dense and consists of an ____ ___ of bony ____ (_____). The cavities between them are filled with ___ or ___ bone marrow. The former is ____ and infiltrated by __ ___, which the latter is involved in ___ __ formation

Answer 7

interconnecting lattice, spicules, trabeculae, yellow, red, inactive, adipose tissue, blood cell

Question 8

Two types of cells found in bone tissue are ___ and ____.

Answer 8

Osteoblasts, osteoclasts

Question 9

Osteoblasts synthesize and secrete the _____ constituents of the ___ ___. Once they have become surrounded by their matrix, they mature into _____

Answer 9

organic, bone matrix, osteocytes

Question 10

Osteoclasts are large, ______ cells involved in bone _____, wherein bone is ___ ___ and_____ are released into the blood

Answer 10

multinucleated, reasborption, broken down, minerals

Question 11

Bone formation occurs by either ___ ___ or by ___ _____. In the former, existing ___ is replaced by bone. This is how __ ___ primarily arise. In the latter, _____ (embryonic or undifferentiated) connective tissue is transformed into and replaced by bone

Answer 11

endochondral ossification, intramembranous ossification, cartilage, longbones, mesenchymal

Question 12

The ____ skeleton is the basic framework of the body, consisting of the ____, __ __ and the __ ___. It is the point of attachment of the ______ _____, which includes the bones of the ___ and the pectoral and ___ girdles

Answer 12

axial, skull, vertebrate column, rib cage, appendicular skeleton, appendages, pelvic

Question 13

___ or ____ joints, hold the bones of the skull together. Bones that move relative to one another are held together by movable ___ and are additionally supported and strengthened by ____. These serve as _____ connectors. ___ attach skeletal ___ to bones and bend the skeleton at movable joints

Answer 13

sutures, immovable, joints, ligaments, bone-to-bone, tendons, muscle

Question 14

The point of attachment of a muscle to a stationary bone (_____ end in ___ muscles) is called the ____. The point of attachment of a muscle to a bone that moves (___ end in limb muscles) is called the ____.

Answer 14

proximal, limb, origin, distal, insertion

Question 15

___ indicates the straightening of a joint, whereas ____ refers to a bending of a joint

Answer 15

extension, flexion

Question 16

Muscle tissue consists of bundles of specialized ____ ___ held together by connective tissue. There are three morphologically and functionally distinct types of muscle in mammals: _____ muscle, ___ muscle, and ___ muscle

Answer 16

contractile fibers, skeletal, smooth, contractile

Question 17

Nervous control of the muscular system involves the axons of the ___ __ of the __ ___ which descend from the brain to synapse on lower motor neurons in the ___ __ and __ ___. Because there are no intervening synapses, the __ ___ is able to provide rapid commands to the skeletal muscles and various other organs. Several other centers can issue somatic motor commands as a result of processing performed at the ___, ___ level. These centers and their associated tracts comprise the _____ _____. The ___ __ located in the mesencephalon, is the component of the extrapyramidal system primarily in control of skeletal __ ____

Answer 17

pyramidal cells, motor cortex, brain stem, spinal cord, pyramidal system, unconscious, involuntary, extrapyramidal system, red nucleus, muscle tone

Question 18

Skeletal muscle is responsible for voluntary movements and is innervated by the __ _____ ___. Each fibre is a ___ cell created by the fusion of several ___ ___ cells. Embedded in the fibres are filaments called ____, which are further divided into contractile units called ____.

Answer 18

somatic nervous system, multinucleated, mononucleated embryonic, myofibrils, sacromeres

Question 19

The myofibrils are enveloped by a modified endoplasmic reticulum that stores ___ ___ and is called the ___ ____. The cytoplasm of the muscle fiber is called the _______, and the cell membrane is called the _____.

Answer 19

calcium ions, sarcoplasmic reticulum, sarcoplasm, sarcolemma

Question 20

The sacrolemma is capable of propagating an __ __ and is connected to a system of __ ____ (T system) oriented ______ to the myofibrils. The T system provides ____ for ___ __ throughout the muscle fibers and can also propagate an AP.

Answer 20

action potential, transverse tubules, perpendicularly, channel ion flow,

Question 21

Because of the high-energy requirements of ____, ___ are very abundant in muscle cells and are distributed along the ____.

Answer 21

contraction, mitochondria, myofibrils

Question 22

Skeletal muscle has striations of __ and ___ bands and is therefore also referred to as ___ ___

Answer 22

light, dark, striated muscle

Question 23

The sarcomere is composed of ___ and ___ filaments. The former are chains of ____ molecules. The latter are composed of organized bundles of ___ molecules

Answer 23

thin, thick, actin, myosin

Question 24

Electron microscopy reveals that the sarcomere is organized as follows: ____ ___ define the boundaries of a single sarcomere, and anchor the ___ ___. The ___ __ runs down the center of the sarcomere, The ___ __ is the region containing thin filaments only. The ___ ___ is the region containing thick filaments only. The ___ ___ spans the entire length of the thick filaments and any overlapping portions of thin filaments. When the muscles contract, the __ ___ move toward each other. Note that during contraction, the ___ ___ is not reduced in size, whereas the ___ zone and __ band are.

Answer 24

z lines, thin filaments, m line, I band, H zone, A band, z lines, a band, h, i

Question 25

Muscle contraction is stimulated by a message from the somatic nervous system sent via a ___ ___. The link between the nerve terminal and the ____ of the muscle fiber is called the ____ ____, The space between the two is known as the ___ or the -__ ___.

Answer 25

motor neuron, sarcolemma, neuromuscular junction, synapse, synaptic cleft

Question 26

Deporlarization of the motor neuron results in the release of ______ from the nerve terminal. This diffuses across the __ ___ and binds to receptors on the ___. If enough receptors are ____ the ___ of the sarcolemma is altered and an ___ ___ is generated

Answer 26

acetylcholine, synaptic cleft, sarcolemma, stimulated, permeability, action potential

Question 27

Once an action potential is generated, it is conducted along the sarcolemma and the ___ __ and into the ___ of the muscle fiber. This causes the sarcoplasmic reticulum to release ____ ions into the ____. This initiates the contraction of the ___ by binding to ___ __ on the actin filaments. ____ changes occur in the proteins that allow ____ heads to bind to these sites on the actin. Use of energy allows a ___ ___ to occur, pulling the Z bands closer together. Actin and myosin ___ past each other and the saromere contracts

Answer 27

t system, interior, calcium, sarcoplasm, sarcomere troponin C, allosteric, myosin, power stroke, slide

Question 28

Several hours after death, all muscles in the body go into a state of __ ___. In this condition, the muscles ___ and become ___ even without action potentials. This is caused by an absence of ___, which is required for the ___ ___ to be released from the actin filaments. The muscles typically remain rigid for ___ to ___ hours after death until the muscle ___ degrade

Answer 28

rigor mortis, contract, rigid, ATP, myosin heads, 12, 24, proteins

Question 29

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

Answer 29

isotonic contraction

Question 30

Type of muscle contraction that includes both concentric and eccentric types of contracts and results in a change in length of the muscle with a corresponding change in tension on that muscle

Answer 30

dynamic contraction

Question 31

Type of dynamic contraction where the muscle fibers shorten and the tension on the muscle increases

Answer 31

concentric contraction

Question 32

Type of dynamic contraction where the muscle fibres lengthen and the tension on the muscle decreased

Answer 32

eccentric contraction

Question 33

Type of muscle contraction that occurs when both ends of the muscle are fixed and no change in length occurs during the contraction but the tension increases

Answer 33

isometric contraction

Question 34

Individual muscle fibres generally exhibit an _____ response. Only a stimulus above the ____ can elicit a contraction. The strength of the contraction of a single muscle fibre ___ be increased, regardless of the strength of the stimulus. However, the strength of contraction of an entire muscle can be increased by recruiting more ___ ___.

Answer 34

all-or-none, threshold, cannot, muscle fibers

Question 35

A simple twitch is the response of a single muscle fiber to a ___ __ at or above the threshold stimulus. The ___ period is the time between stimulation and the onset of contraction. During this time lag, the __ spreads along the sarcolemma and ___ ions are released. After the ____ period, there is a brief ____ period, during which the muscle is ____ to a stimulus. This period is known as the __ ____ ____

Answer 35

brief stimulus, latent, AP, Ca2+, contraction, relaxation, unresponsive, absolute refractory period

Question 36

When the fibers of a muscle are exposed to very ___ stimuli, the muscle cannot fully relax. The contractions begin to ____, becoming stronger and more ____. This is known as ___ ___. The contractions become ___. This type of contraction is called _____ and is stronger that the simple twitch of a single fibre. If this is maintained, the muscle will ___ and the contraction will weaken

Answer 36

frequent, combine, prolonged, temporal summation, continuous, tetanus, fatigue

Question 37

____ is a state of partial contraction. Muscles are never completely ____ and maintain a partially contracted state at all times

Answer 37

tonus, relaxed

Question 38

During periods of strenuous activity, skeletal muscles convert ___ to ___ __ through the process of glycolysis. This process enables skeletal muscles to continue contracting even in the absence of ____. ___ __ is generated when pyruvic acid reacts with the enzyme ___ ____. This process allowss the pyruvate to enter the ___ ___/ ____ cycle

Answer 38

glucose, pyruvic acid, oxygen, lactic acid, lactate dehydrogenase, citric acid/krebs

Question 39

The purpose of the cori cycle during periods of strenuous activity is to convert ___ __ in the ___ to glucose for discharge into the ___. The muscles are then able to use it as an immediate source of ___ or to rebuild their ___ ___. Conversion of glucose into pyruvate is necessary for the creation of ___ during periods of strenuous exercise and does not involve the ___ cycle.

Answer 39

lactic acid, liver, bloodstream, energy, glycogen reserves, ATO, cori

Question 40

Smooth muscle is responsible for ____ ___ and is innervated by the ____ ____ ___. Smooth muscle is found in the __ __, bladder, ___ and ___ ___ walls, etc. Smooth muscle cells possess one ____ ____ nucleus and lack the ____ of skeletal muscle

Answer 40

involuntary actions, autonomic nervous system, digestive tract, uterus, blood vessel, centrally located, striations

Question 41

The muscle tissue of the heart is composed of ___ ___ fibers. These fibers possess characteristics of both __ and ___ muscle fibers. Like skeletal muscle, ___ and ___ filaments are arranged in sarcomeres, giving cardiac muscles a ___ appearance. However, they generally only have __ or ___ centrally located nuclei

Answer 41

cardiac muscle, skeletal, smooth, actin myosin, striated, one, two

Question 42

____ is the primary source of energy for muscle contraction. Very little of this is actually ___ in the muscles, so other forms of energy must be stored and rapidly ___ into it.

Answer 42

ATP, stored, converted

Question 43

In vertebrates, energy can be stores in a high energy compound called ___ ___

Answer 43

creatine phosphate

Question 44

___ is a hemoglobin like protein found in muscle tissue. It has a high __ ___ and maintains the ____ ___ in muscles by tightly binding to O

Answer 44

myoglobin, oxygen affinity, oxygen supply