muscular and skeletal systems

Question 1

function of animmal skeletal systms

Answer 1

physical support and locomotion

Question 2

muscular systm main dunction

Answer 2

generaters force

Question 3

endoskleton

Answer 3

serves as framwork within all vertebrate organisms
muscles are attached to bones, permitting movement
th endoskeleton also provides protection by surrounding delicate internal organs with bone
the rib cage protects thoracic organs (heat and lungs), skull and vertebral column protect brain and spinal cord
2 major components of skeleton are cartilage and bone

Question 4

cartilage

Answer 4

a type of connective tissue that is softer and more flexible than bone
retained in adults where firmness and flexibility is needed
ex: ear, nose, walls of larynx and trachea, skletal joints contain cartilage

Question 5

chrondrocytes

Answer 5

cells responsible for synthesizing cartilage

Question 6

bone

Answer 6

mineralized connective tissue that has ability to withstand physical stress
adapted for body support, bone tissue is hard, and also elastic and lightweight
2 basic types: compact bone and spongy bone

Question 7

compact bone

Answer 7

dense bone that does not appear to have an cavities when observed with naked eye
the bony matrix id deposited in structural units called osteons
each osteon has a central microscopic channel called Haversian canal surrounded by a number of concntric circles of bony matrix (calcium phosphate) called lamellae

Question 8

osteon

Answer 8

the bony matrix is deposited in structural units called osteons (Haversian systems)
each osteon has a central microscopic channel called a Haversian canal, surrounded by cencentric circles of bony matrix (calcium phosphat) called lamellae

Question 9

spongy bone

Answer 9

much less dense than compact bone, and consists of an interconnecting lattice of bony spicules (hard body)
the cavities between the spicules are filled with yellow or red bone marroe

Question 10

yellow bone marrow

Answer 10

inactive and infiltrated by adipose tissue

fills the cavities between spicules of spongy bone

Question 11

red bone marrow

Answer 11

involved in blood cell formation

fills the cavities between spicules of spongy bone

Question 12

the 2 types of cells found in bone tissue

Answer 12

osteoblasts and osteoclasts

Question 13

osteoblasts

Answer 13

1 of 2 type of cells found in bone tissue
synthesize and secrete the organic constituents of the bone matrix
once they have become surrounded by their matrix they mature into osteocytes

Question 14

osteocytes

Answer 14

made of mature osteoblasts

Question 15

osteoclasts

Answer 15

1 of 2 types of cells in bone tissue
are large, multinucleated cells involved in bone reabsorption when bone is broken down and minerals are released into blood

Question 16

axial skeleton

Answer 16

is the basic framework of the body
consisting of the skull, vertebral column and rib cage
it is the point of attachment of the appendicular skeleton (includes bones of the appendages (limbs) anf the pectoral girdles (connect to arm) and pelvic girdles

Question 17

appendicular skeleton

Answer 17

includes the bones of the appendages (limbs) and the pectoral and pelvic girdles

Question 18

how are these bones held together:

• sbones of the skull
• bones that move relative to one another

Answer 18

sutures or immovable joints hold the bones of the skull together
bones that move relative to one another are held together by movable joints and are supported and strengthened by ligaments

Question 19

ligaments

Answer 19

serve as bone-to-bone connectors

Question 20

tendons

Answer 20

attach skeletal muscle to bones and bend the skeleton at the movable joints

Question 21

origin

Answer 21

point of attachment of a muscle to a stationary bone

(proximal end) in limb muscles

Question 22

insertion

Answer 22

attachment of a muscle to the bone that moves (distal end in limb muscles) is called the insertion

Question 23

extension and flexion

Answer 23

indicates a straightening of a joint, whereas flexion refers to a bending of a joint

Question 24

the 3 types of muscle

Answer 24

skeletal muscle
smooth muscle
cardiac muscle

Question 25

pyramidal system

Answer 25

nervous control of the muscular system involves axons of the pyramidal cells of the motor cortex they descnd from the brain to synapse on lower motor neurons in the brain stem and spinal cord because hthere are no intervening synapses, the pyramidal system is able to provide rapid commands the the skeletal muscles and various other organs

Question 26

extrapyramidal system

Answer 26

centers that can issue somatic motor commands as a result of processing performed at the unconscious, involuntary level these centers and their associated tracts comprise the extrapyramidal system the red nucleus located in the mesencephalon is he component of the extrapyramidal system that is primarily in control of skeletal muscle tone (contraction of muscles)

Question 27

skeletal muscle function and structure

Answer 27

responsible for voluntary movements is innervated by somatic nervous system each fiber is a multinucleated cell created by the fusion of several mononucleated embryonic cells embeded in the fibers are filaments called myofibrils, which are further divided into contractile units called scaromeres the myofibrils are enveloped by a modified endoplasmic reticulum that stores calcium ions and is called the sarcoplasmic reticulum

Question 28

``` myofibrils sacromeres sacroplasmic reticulum sarcoplsm sarcolemma mitochondria ```

Answer 28

myofibrils are filaments embeded in muscle fibers they are further divided into contractile (capable of producing a contraction) units called sacromeres the myofibrils are enveloped by a modified endoplasmic reticulum that stores calcium ions and is called the sacroplasmic reticulum the cytoplasm of a muscle fiber is called the carcoplasm cell membrane of a muscle fiber is called a sarcolemma because of the high energy requirements of a contraction, mitocondria are very abundant in misicle cells and are distributed along the myofibrils

Question 29

sarcolema

Answer 29

cell membrane of a muscle fiber it is capable of propagating an action potential and is connected to a system of transverse tubules (the T system) oriented perpendicularly to the myofibrils (filaments embeded in muscle fiber)

Question 30

sarcoplasmic reticulum

Answer 30

myofibrils (filaments embeded in muscle fibers) are enveloped by a modified endoplasmic reticulum that stores calcium ions and is called the sarcoplasmic recticulum

Question 31

T system

Answer 31

a system of transverse tubules, oriented perpendicularly to the myofibrils T system provides the channels for ion flow throughout the muscle fibers and can also propagate action potentials

Question 32

striated muscle

Answer 32

skeletal muscle has striations of light and dark bands and is therefore referred to as striated muscle

Question 33

sacromere structure Z lines, M line, I band, H zone, A band muscle contraction

Answer 33

myofibrils are filaments embeded in muscle fibers they are further divided into contractile (capable of producing a contraction) units called sacromeres sacromeres are made of thin and thick filaments the thin filaments are chains of actin molecules the thick filaments are composed of organized bundles of myosin molcules organization of a sacromere: Z lines: define the boundaries of a single sacromere and anchor the thin filaments M line: runs down the center of the sacromere I band: is the region containing thin filaments only H zone: the region containing thick filaments only A band: spands the entire length of the thick filaments and any overlapping portions of th thin filaments when muscles contract, the Z lines move toward each other. during contractiong the A band is not reduced in size, but the H and I bands are

Question 34

how arw muscle contrations stimulated

Answer 34

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

Question 35

neruomuscular junction

Answer 35

the link between the nerve terminal (synaptic bouton) (bringing the stimualtion from the somatic nervous system) and the sacrolema of the muscle fiber

Question 36

synapse

Answer 36

the space between the nerve terminal and the sarcolema (cell membrane of muscle fiber) is called the synapse or synaptiic cleft

Question 37

how is an action potential generated in the muscle, and the direction it travels

Answer 37

depolarization of motor neuron results in the release of neruotransmitters from the nerve terminal the neurotransmitter diffueses across the synaptic cleft and binds to special receptor sites on the sarcolema (cell membrane) if enough of these recetors are stimulated, the permeability of the sarcolema is altered and an action potential is made once the action potential is made, it is conducted along the sarcolema and the T system and into the interior of the muscle fiber

Question 38

muscle (sacromere) contraction mechanism

Answer 38

once an action potential is made, it goes along the sarcolema (cell membrane) and the T system and into the interior of the muscle fiber this causes the sarcoplamsic reticulum to release Ca2+ ions into the sacroplsm the Ca2+ ions initiate the contracition of the sarcomere by binding to troponin C on the actin filaments allosteric changes occur in the proteins that allow myosin heads to bind to these sites on the actin use of energy allows a power stroke to occur, pulling the Z bands closer together actin and myosin slide past each other, and the sacromere contracts

Question 39

rigor mortis

Answer 39

several hours after death all the muscles in the body go into a state of rigor mortis the muscles contract and become rigid, even without action potentials the rigidity is caused by an absense of ATP which is required for myoisn heads to be released from the actin filaments muscles remain rigid for 12 to 24 hours until the muscle proteins degrade

Question 40

5 major types of muscle contractions

Answer 40

``` isotonic isometric dynamic concentric eccentric ```

Question 41

isotonic muscle contraction

Answer 41

occurs when a miscle shortens against a fixed load while the tension in that muscle remains constant ex: lifting weights

Question 42

dynamic muscle contraction

Answer 42

includes both conntric and eccentric types of contraction | results in a change in length if a muscle with a corresponding change in tension on that muscle

Question 43

concentric contraction

Answer 43

a type of dynamic contraction | muscle fibers shorten and the tension on the muscle increases

Question 44

eccentric contraction

Answer 44

type of dynamic contraction | muscle fiber lengthens anf the tension on the muscle increases

Question 45

isometric contraction

Answer 45

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

Question 46

threshold and muscle coontaction

Answer 46

individ muscle fibers exhibit and all-or-none response | only a stimulus above a minimal value called the threshold value can illicit a contraction

Question 47

strength of muscle fiber contraction versus strength of entire muscle contraction

Answer 47

the strength of the contraction of a single muscle fiber can't be increased regardless of strength of stimulus BUT the strengh of contraction of the entire muscle can be increased by recruiting more muscle fibers

Question 48

simple twitch

Answer 48

the response of a single muscle fiber to a brief stimulus at or above the threshold stimulus and consists of latent period, a contraction period and a relaxation period latent period: the time between stimulation and the onset of contraction during this time lag, the action potential spreads along the sarcolemma and Ca2+ ions are released after the contraction period, there is a brief relaxation period during which the muscle is unresponsive to a stimulus - known as absolute refractory period

Question 49

tetanus contraction

Answer 49

when fibers of a muscle are exposed to very frequen stimuli, the uscle cannot fully relax the contractions begin to combine, becoming stronger and more prolonged-known as temporal stimulation the contractions become continuous when the stimuli are so frequent that the muscle cannot relax known as a tetanus contraction, and is stronger than a simple twitch of a single fiber if tetanus is maintained, the muscle will fatigue and the contraction will weaken

Question 50

tonus

Answer 50

is a state of partial contraction | muscles are never completely relaxed and maintain a partially contracted state at all times

Question 51

the different types of muscle responses

Answer 51

simple twitch tetanus tonus

Question 52

energy generation in muscles during strenuous activity

Answer 52

during periods of strenous activity: -skeletal muscles convert glucose to pyruvic acid through glycolysis this allows skeletal muscles to continue contracting even in absense of oxygen -lactic acid is generated when pyruvic acid reacts with the enzyme lactate dehydrogenase- this process is allows pyruvate to enter the citric acid cycle

Question 53

cori cycle

Answer 53

during periods of strenous activity, it conerts lactic acid in the liver to glucose for discharge in the bloodstream once glucose is in the blood, the muscles are able to use the glucose as an imtrmediate source of energy or to rebuild their glycogen reserves - conversion of glucose into pyruvate in the muscle cells is necessary for making ATP during periods of activity and doesn't involve the Cori cycle - during periods of intense exercise, the production of lactic acid is increased and glycogen is broken down into glucose; however it is not by means of the Cori cycle

Question 54

smooth muscle

Answer 54

responsible for involuntary actions and is innervated by the autonomic nervous system found in digestive tract, bladder, uterus, blood vessel walls etc smooth muscle cells possess one centrally located nucleus and lack the striations of skeletal muscle

Question 55

caridac muscle

Answer 55

muscle tissue of heart is made of cardiac muscle fibers these fibers have charactristics of both skeletal and smooth muscle fibers as in the skeletal muscle, actin and mysin filaments are arranged in sacromeres, giving cardiac muscles a striated apprearence hoever, cardiac muscle cells generally have only one or 2 centrally located nuclei.

Question 56

summary of smooth muscle

Answer 56

- nonstriated - one nucleus per cell - involuntary/autonomic nervous system - smooth continuous contractions

Question 57

cardiac muscle summary

Answer 57

- striated - one or two nuclei per cell - involuntary/autonomic nervous system - strong, forceful contractions

Question 58

skeletal muscle summary

Answer 58

- striated - multinucleated cells - voluntary/somatic nervous system - strong, forceful contractions

Question 59

energy used in muscles

Answer 59

ATP is primary source of energy for muscle contraction | very little ATP is actually stored in the muscles so other forms of energy must be stores and rapidly converted to ATP

Question 60

Creatine phosphate

Answer 60

in vertebrates, energy can be temporarily stored in high-energy compound called creatine phosphate

Question 61

myoglobin

Answer 61

is a hemoglobin-like protein found in muscle tissue | myoglobin has high oxygen affinity and maintains oxygen supply in muscles by tightly binding to oxygen