question

Name the 3 types of muscles

answer

1. skeletal 2. cardiac 3. smooth

question

Describe the skeletal muscle

answer

-location: attach and cover bony skeleton -have striations -voluntary -multinucleated

question

Describe the cardiac muscle

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-striated to a degree -only found at the heart -involuntary control -intercalated discs -uninucleated

question

Describe smooth muscle

answer

-found in walls of viscera -no striation -uninucleated -contracts slowly

question

Name similarities in all three muscle types (skeletal, cardiac, and smooth)

answer

-elongated in shape -contraction of the muscle depends on two filaments, ACTIN and MYOSIN

question

Name functions of muscles

answer

movement- muscle contraction causes bone to move (skeletal muscle only) maintains posture - muscle attaches to the spine, scapula, back of the head -> provides posture and balance Stabilizes joints - ex: glenoid cavity, shallow cavity, needs to have a strong muscular component in order to stabilize (most have musculature and ligamentous support)

question

Name functional characteristics of muscle

answer

-excitability: the ability to receive and respond to a stimulus (sensory stimuli --> sensory response --> motor response) -Contractibility: the ability of a muscle to shorten and lengthen, can be concentric or eccentric -elasticity: ability of a muscle to recoil and resume its resting length after being stretched (includes the recoil effect)

question

Recoil effect

answer

-the muscle that is once stretched can be returned back to its original size -myofibrils and connective tissue are not responsible for this movement -elastic fibers allow for the muscle to shorten and lengthen and return back to its original size

question

Which of the 3 types of muscles are multinucleated?

answer

-skeletal

question

Which of the 3 types of muscles are uninucleated?

answer

-cardiac and smooth

question

Which of the 3 types of muscles are voluntary?

answer

-skeletal -(the diaphragm of smooth muscle is voluntary to a degree)

question

Which of the 3 types of muscles are involuntary?

answer

cardiac and smooth (diaphragm of the smooth muscle is voluntary to a degree)

question

Which of the three types of muscles are striated?

answer

skeletal and cardiac (cardiac is striated to a degree)

question

Where is skeletal muscle found?

answer

attaches and covers the bony skeleton

question

Where is the cardiac muscle found?

answer

only in the heart

question

Where is smooth muscle found?

answer

found in the walls of the viscera

question

Define concentric contractibility

answer

-muscle moves to shorten in length

question

Define eccentric contractibility

answer

-muscle moves to lengthen in length

question

From outer to inner, name the connective tissue wrappings of muscles

answer

Epimysium, perimysium, Endomysium

question

From inner to outer, name the connective tissue wrappings of muscles

answer

endomysium, perimysium, epimysium

question

Describe endomysium

answer

-delicate connective tissue that surrounds individual MYOFIBRIL

question

define myofibril

answer

-individual unit or fiber that composes the muscle

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Describe perimysium

answer

-coarse connective fiber tissue that is stronger than endomysium with surrounds an individual FASCICLE

question

define fascicle

answer

bundle of myofibrils

question

describe epimysium

answer

-most external connective tissue wrapping -thick FIBROUS connective tissue -dense; allows for protection and support -surrounds BUNDLE OF FASCICLES

question

Sarcomere

answer

-functional unity of the myofibril -area between one z line to another z line -each myofibril has an infinite amount of zlines and sarcomeres -when they contract, the z lines are going to get closer together -all the sarcomeres must work in unison with one another to create movement

question

Myosin filaments

answer

-myosin bands within the sarcomere -thicker bands and run midline on the sarcomere -cannot polarize light, therefore known as DARK bands -runs the length of the A bands

question

Actin filaments

answer

-thinner of the filaments -run LATERAL to the midline (never actually reach the midline) -starts laterally, two fivers that never actually meet or make the middle -can polarize light, aka Light bands

question

H band-

answer

gap where the actin does not reach the middle

question

What is the mechanism of contraction for skeletal muscle fiber?

answer

-individual sarcomeres shorten; we are only concerned with the MYOSIN and ACTIN filaments integration and interaction

question

Describe the SLIDING FILAMENT theory of muscle

answer

-thick myosin filaments have an oblique HEAD on them -thin actin filaments have thin ACTIVE SITES -When at rest -> there is NO interaction between the myosin head and the actin filaments -during muscle contraction -> needs Ca, ATP, and Mg -the myosin head forms a temporary bond with the actin active sites -> a contraction; cross bridging attachment -when the muscle contracts, it locks the filaments together -the MYOSIN HEAD goes through a POWER STROKE -z lines are going to shorten, along with SARCOMERE -ACTIN filaments become more medial and closer to the myosin filaments -the myosin head will rotate into the actin active sites and will bind as a result of a POWER STROKE - the ATP causes the myosin head to rotate into the active site -Temporary cross bridging - muscle contraction

question

Define power stroke

answer

causes rotation of the myosin head into the active site of the actin filaments

question

What elements are needed for cross bridging attachment to occur?

answer

-calcium- involved in muscle contraction -ATP- energy source (hydrolyzed to ADP) -Magnesium- acts as a cofactor for contraction

question

Describe crossbridging detachment

answer

-when the muscle relaxes -z lines, actin and myosin filaments must return to normal (no longer shortened, or lengthened) -power stroke will be broken down by calcium and ATP once again to bring it back to the original configuration ATP binds to the myosin head to detach the myosin from actin active sites when muscle relaxes, the myosin heads are going to stop rotating and the myosin heads and active sites will separate.

question

Explain Rigor mortis

answer

-occurs when a person dies --> body no longer produces ATP -crossbridging is locked, there is no ATP to release the myosin head -the connection between the myosin and the actin never released, so the muscle remains in a contracted state -when the bicep contracts, the tricep has to relax, but if there is no ATP, the movement cannot occur

question

What is a muscle twitch?

answer

the response of a muscle to single stimuli

question

What are the 3 stages of muscle contraction?

answer

1. latent period (hidden period) 2. Period of contraction 3. Period of relaxation

question

Describe latent period

answer

-ONE OF THE THREE STAGE OF MUSCLE CONTRACTION -muscles are constantly in a partial state for contraction (such as for posture) we can change the level of contraction to either rest, contraction or a full contraction -the latent stage is a period of no voluntary contraction -the muscle is relatively AT REST according to our regular usage for the muscle

question

Describe period of contraction

answer

-ONE OF THE THREE STAGES OF MUSCLE CONTRACTION -contraction phase where muscle contracts to either lengthen or shorten -always need a frame of reference -acknowledge agonistic and antagonistic muscles

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Describe period of relaxation

answer

-ONE OF THE THREE STAGES OF MUSCLE CONTRACTION -muscle goes back to its original length -the tension is released from the muscle that developed in phase 2 -when the muscle stops contracting, and enters the period of rest

question

What is threshold stimulus?

answer

-aka initial stimulus - the minimal stimulus that will cause muscle contraction - the smallest amount of force that is required to allow for muscle contraction

question

What is maximal stimulus?

answer

-aka final stimulus -strongest muscular contraction -the point where the muscle will be at the highest possible contraction -even if we increase the stimulus, the muscle will be unable to contract past this single point -voluntary response --> we control our responses -the amount of effort we put in, can control the stimulus for the muscle

question

what is muscle tone?

answer

-every skeletal muscle in the body is in a state of partial contraction -always in a state where they can fully contract -can focus on biceps and think of the contraction and feel contraction -muscle tone will allow you to contract -myofibrils are acting functionally

question

What is isometric contraction? Example?

answer

-the muscle develops tension but does not shorten -very important -main contraction that is useful for us as clinicians or physicians -contractions are usually induced after an injury -example: cervical whiplash injury -if hit from incredible force, neck goes into severe flexion and then severe extension, and the resultant is 0

question

What is hypoflexion?

answer

reduced ability to flex a limb

question

Isotonic contraction

answer

-muscle will shorten and move a load that cannot be realistically moved -less important -shortening the muscle but adding trauma to the muscle -not really being beneficial to the muscle -causes injuries through tissue or muscle damage -when thinking of isotonic, refer to concentric, contraction, or eccentric contraction

question

What is metabolism?

answer

- the sum of all catabolic and anabolic reactions in your body

question

What is a catabolic reaction?

answer

breaking down something (I. e. breaking down food, glycogen -> glucose units

question

What is an anabolic reaction?

answer

-building something up (i.e. body takes amino acids to make proteins)

question

What are the 3 pathways by which ATP is regenerated during muscle metabolism?

answer

1. Interaction of ADP with a substance called CP (Creatine Phosphate) 2. Aerobic respiration 3. Fermentation

question

Aerobic respiration

answer

-oxygen -resting muscle contraction - fatty acids -active muscle contraction - glucose -glucose Is C6H12O6 balanced with O2 to get 6H2O + 6O2 + 38ATP involved the Krebs Cycle and the ETC

question

What causes oxidation?

answer

-glucose combined with oxygen

question

Fermentation or Anaerobic Respiration

answer

-lactic acid production -complete oxidation of glucose will stop at some point, won't et 38 ATP, get lactic acid -builds up in the muscle and usually during anaerobic activity (like bench pressing or weight lifting) -when a person gets out of breath, lactic acid built up -gets about 2 ATP -goes through glycolysis but not Krebs cycle or ETC -that's where we lose production of ATP

question

Muscle Fatigue is due to either what 2 things?

answer

1. ATP production is less than ATP use 2. excessive accumulation of Lactic Acid in the muscle as a result of anaerobic metabolism

question

What are the 3 muscle fiber types?

answer

Red (slow) twitched fivers white (fast) twitch fivers Intermediate (fast) twitch fibers

question

Red (Slow) Twitch Fibers

answer

-active for a long period of time -fatigue resistant and high endurance (lots of oxygen) -like running but not lifting -red color due to large amount of Fe Iron- myoglobin and hemoglobin major fuel source is fat, myoglobin is important in its relationship to oxygen -high endurance and fatigue resistant, more for cardiovascular activity!

question

What's the difference between myoglobin and hemoglobin?

answer

myoglobin stores oxygen in the muscle fibers while hemoglobin transports oxygen

question

What is the percentage of hemoglobin in the red blood cell?

answer

33%

question

What is red slow twitch fiber's major fuel source?

answer

fat

question

White (Fast) twitch fibers

answer

-decrease in iron, decrease in mitochondria, decrease in myoglobin --cannot store oxygen -involved with more weightlifting/ muscle activity, not with cardiovascular activity 1. depend in actic acid pathways to generate ATP during contraction 2. as lactic acid builds they fatigue quickly

question

What is muscle hypertrophy?

answer

-means enlargement of muscle -2 different types: TRUE and FALSE -TRUE hypertrophy- nuilds muscle gradually via lifting and high intensity exercises -muscle pitted against high resistance -tears muscle -over time, becomes stronger or enlarges FALSE hypertrophy -AKA pseudohypertrophy -use of steroids and drug enhancers -building muscle mass in an artificial way

question

What is Resistance Exercise?

answer

-can be used to increase muscle -important for rehabilitation after surgery/injury -mostly important with physical therapy -by vgorously stretching the muscle fibers, the fibers contain more mitochondria and myofibrils

question

What is disuse muscle atrophy?

answer

-exact opposite of true muscle hypertrophy -muscle gets smaller and weaker because it's not being used -usually sen with elderly (esp. bed-ridden) or young/middle-age people have been bedridden for a long period of time -due to muscle immobilzation -over a period of time, when not used -> become nonfunctional (esp. if someone is younger) -when it becomes smaller or weaker, muscle loses strength and then gets replaced by fibrous and fatty tissue (now nonfunctional) -muscle won't respond to carbon dioxide or oxygen -atrophy in muscle is nonuse, atrophy in organ is nonfunctioning -a good example is DIABETES -scar tissue

A&P Chapter 9 Muscle Physiology – Flashcards

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