Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Animal Anatomy and Physiology > Muscles Pt. 1 > Flashcards

Muscles Pt. 1 Flashcards

1
Q

Muscle has 4 common characteristics

A

-Excitability
-Contractibility
-Extensibility
-Elasticity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Excitability

A

Respond to a stimulus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Contractility

A

Shorten in length when stimulated

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Extensibility

A

will stretch when pulled

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Elasticity

A

return to normal shape and length

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

3 types of muscle

A

skeletal, cardiac, and smooth

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Skeletal muscle

A

-controlled by the conscious mind
-Moves bones of the skeleton
-is usually what we think of when we hear the word muscle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Cardiac muscle

A

-found only in the heart
-starts the entire heart beating before an animal is born and keeps it going until it dies

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Smooth Muscle is found where?

A

Found all over the body - eyes, air passageways, lungs, stomach/intestines

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Skeletal Muscle - Gross Anatomy

A

Skeletal muscle is a group of muscle cells surrounded by a fibrous connective sheath called Epimysium (means upon muscle)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Most skeletal muscles are attached to bones at both ends by

A

Tendons - Tough, fibrous connective tissue - they are a continuation of the epimysium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Some muscles are attached to bones or other muscles by sheets of fibrous CT called

A

Aponeuroses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the most prominent aponeuroses??

A

Linea alba (white line) - Runs lengthwise between abdominal muscles on the ventral midline (where you cut during a spay)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Which site of attachment is the most stable?

A

origin of the muscle - does not move much when the muscle contracts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Which site of attachment undergoes the most movement?

A

insertion of the muscle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What happens to the muscle when a nerve impulse hits a muscle?

A

it contracts - pulls on its attachment - the contraction produces movement of bones and other structures

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Skeletal muscles rarely act alone - they work in groups - One group _________ and the other _________

A

One group makes the movement - this group is known as the agonist (prime mover) - other groups stabilize nearby joints

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Antagonist

A

muscles the directly opposed the action of an agonist
- partial contraction - antagonists can smooth out the movements of the agonist
-Can contract forcefully - results in rigidity and lack motion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Synergist

A

The skeletal muscle that contracts at the same time as an agonist and assists it in carrying out its action
- Ex: deep flexor muscle flexes the digit at the same time the superficial digital flexor flexes to aid in movement

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Fixator

A

Stabilizes joint to allow other movements to take place

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Skeletal muscle cells are large (not wide, but long), these are called

A

fibers rather than cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Skeletal fibers can have up to 100 or more per fiber. All are located just beneath __________

A

the sarcolemma - muscle cell membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Muscle fibers are made up of hundreds or thousands of smaller _______ packed together lengthwise

A

myofibrils - these fibrils are made of thousands of even tinier protein filaments

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Organelles between the myofibrils in a muscle fiber include:

A

-many energy producing mitochondria
-extensive network of sarcoplasmic reticulum - storage organelle for Ca ions
-A system of tubules called transverse tubules or T-tubules - extend in from the sarcolemma

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

One myofibril is made up of a series of protein filaments. Together they form the contractile units of a myofibril. Each contractile unit is known as _________

A

sarcomere - the basic contracting unity of skeletal muscle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Sarcomeres lay end to end in one myofibril. Each sarcomere has a disc on each end

A

these are know as the Z line or Z disc
-Sarcomeres share these discs - there is one common disc between adjacent sarcomeres

27
Q

Inside each sarcomere, there are two primary protein filaments responsible for contraction

A

Actin filaments
Myosin filaments

28
Q

Actin filaments

A

thin protein filaments
Attach to the Z lines and extend toward the center of the sarcomere - actin filaments don’t meet

29
Q

Myosin filaments

A

thick protein filaments
Appear to float in the middle of the sarcomere between the parallel actin fibers - THEY DO NOT CONNECT TO Z LINES

30
Q

Looking at the myofibril under the microscope, there will be large light-colored bands

A

-These are I-bands - made of thin actin filaments
-Extend from one end of thick myosin in one sarcomere across the Z-line to the beginning of the myosin fibers of the next sarcomere
-In the center of the band is the dark Z disc/line - this is the attachment site for actin filaments
-From one z-line to the next is one sarcomere

31
Q

Between the light I-bands are darker bands called

A

A-bands and H-bands

32
Q

A-bands

A

are areas where the thick myosin and thin actin filaments overlap

33
Q

H-bands

A

The light-colored area located in the middle of the A-band
Made up of myosin filaments only - no overlapping actin filaments
-Does not cover the entire width of the myosin filament

34
Q

Actin fibers are actually ……..

A

Two strands of protein twisted together - In a helical structure like DNA
-The myosin molecule has a twisted tail attached to two globular heads - They form cross-bridges to actin and interact with the actin to shorten the sarcomere during contraction

35
Q

Sites where the ends of the motor never fibers connect to muscle fibers are called

A

Neuromuscular junctions - there is a small space between the end of the nerve fiber and sarcolemma called the synaptic space

36
Q

In the end of a nerve fiber in a neuromuscular junction are tiny sacs called

A

synaptic vesicles

37
Q

synaptic vesicles contain a chemical neurotransmitter called

A

Acetylcholine (ACh)

38
Q

When an impulse comes down the motor neuron It causes ACh release

A

Quickly diffuses across the synaptic space - Binds to the sarcolemma receptors - This starts contraction of the muscle fiber

39
Q

The effect of ACh on the receptor is very short

A

ACh found in the synaptic space - quickly removes ACh from the receptor and splits it apart - this ends the effect of the nerve impulse

40
Q

Each nerve fiber innervates more than one fiber

A

the number of muscle fibers per nerve fiber determines how small a movement will result from the stimulus

41
Q

motor unit

A

used to describe one nerve fiber an all the muscle fibers it innervates

42
Q

endomysium

A

a delicate CT layer that surrounds the individual skeletal muscle fiber - composed of fine reticular fibers

43
Q

Groups of skeletal muscle fibers are known as ____

A

fascicles

44
Q

these fascicles are bound together by a tougher CT layer called

A

perimysium - composed of reticular fibers an thick collagen fibers

45
Q

Groups of fascicles are surrounded by

A

epimysium
-a fibrous connective tissue layer composed of largely of tough collagen fibers
- this is the outer covering of the entire muscle

46
Q

these 3 layers (fascicles, perimysium, and epimysium) are continuous with ____

A

tendons or aponeuroses

47
Q

when a muscle is relaxed

A

actin and myosin are barely overlapped

48
Q

when the fiber is stimulated

A

-Globular heads of the myosin tails - rachet back and forth and pull actin filaments on both sides towards the center of the myosin filaments
-Sliding of filaments over each other shortens the sarcomere
- all sarcomeres moving together causes entire muscle contractions

49
Q

An individual muscle fiber works on the all-or-nothing principle

A

it either moves or it doesn’t

50
Q

The nervous system controls movement by controlling the number of muscle fibers it stimulates

A

-Small fine movements only require a few fibers to contract
-Larger movements require many fibers to contract
-This is how we develop muscle memory

51
Q

Muscle contraction requires much energy

A

Immediate energy source that powers the sliding of actin and myosin filaments is adenosine triphosphate (ATP) - Produced by mitochondria

52
Q

ATP can release energy, recharge, and release it again

A

-ATP has 3 phosphate groups attached to an adenosine core - when one phosphate is split off- ATP -> ADP - a lot of energy is released
-Actin and myosin filaments slide

53
Q

ADP has to be charged back to ATP

A

Creatine phosphate (CP) does this
-When CP splits, the released energy adds a phosphate group to ADP - Making it turn into ATP

54
Q

Ultimate source of energy used to make ATP and CP to keep the whole system going

A

Catabolism = the breakdown of nutrient molecules
- The main compounds used are glucose and oxygen

55
Q

Glucose

A

a sugar molecule that is the primary energy source of most body cells
- muscles have a large blood supply that constantly bring new supplies of glucose and oxygen to muscle fibers

56
Q

When glucose and oxygen supplies are plenty, muscles store energy

A

Glucose is stored as glycogen
Oxygen is stored in a large protein molecules called myoglobin

57
Q

When strenuous muscle activity depletes the O2 supply

A

Myoglobin can release stored O2 supply and resupply the fiber

58
Q

As long as there is enough oxygen to keep up with demand, myoglobin can continue to release O2 - This is known as

A

aerobic (oxygen consuming) metabolim
- max amount of energy is extracted from each glucose molecule

59
Q

Sometimes O2 demand exceeds available supply and the muscle fiber shifts to …

A

anaerobic metabolism
- this is not as efficient as aerobic
- Incomplete glucose breakdown - Lactic acid is a byproduct

60
Q

Why do we breath heavy after strenuous activity?

A

Lactic acid in the blood stream diffuses to liver to be turned into glucose
-this process requires O2
- Heavy breathing is a way to recover the O2 debt

61
Q

Muscles are less than 100% efficient at converting energy to an activity. A lot of energy is converted to _______

A

heat
muscle activity is one of the main heat producers in the body

61
Q

If too much heat is made

A

heat dissipation takes plave

62
Q

If hypothermia is present

A

Muscles generate heat by small, spasmodic contractions - Shivering

Animal Anatomy and Physiology (20 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions