Muscle Physiology

Front 1

Name striated muscles

Back 1

Cardiac muscle and skeletal muscle

Front 2

Tendons attach

Back 2

Muscle to bone

Front 3

The muscle is called flexor if

Back 3

The centers of connected bones are brought together when this muscle contracts

Front 4

The muscle is called an extensor if

Back 4

The bones move away when the muscle contract

Front 5

Flexor - extensor pairs are called

Back 5

Antagonistic muscle groups

Front 6

Muscle stem cells are called

Back 6

Satellite cells

Front 7

Groups of muscle fibers form

Back 7

Facicles

Front 8

The cell membrane of a muscle fiber is called

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Sacrolema

Front 9

The cytoplasm of a muscle fiber is

Back 9

Sarcoplasm

Front 10

The main intracellular structures in striated muscles are

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Myofibrils

Front 11

Myofibrils are composed of

Back 11

Troponin , actin and tropomyosin that form thin filaments, myosin - thick filament and titin and nebulin

Front 12

A triad is

Back 12

One T tubule between two terminal cisternae

Front 13

What allows action potentials to move rapidly from cell surface to the interior of muscle fiber?

Back 13

T tubule

Front 14

Each myofibrils is composed of several types of proteins organised into repiting contractile structures called

Back 14

Sacromeres

Front 15

A motor protein with the ability to create movement is

Back 15

Myosin

Front 16

Z band in sacromere is

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Zigzag protein where actin chains join together

Front 17

I bands in sacromere are

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The light region occupied only by actin filaments

Front 18

Z disk run through the middle of...

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I BAND

Front 19

A band is the darkest of the sacromere band and compasses...

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A band compasses the entire length of think fillament and thin filaments on peripheral ends

Front 20

H ZONE IS

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the middle of A band where only thick filaments are found

Front 21

M line is

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Middle of A bond

Front 22

The proper alignment of filaments within sacromere is ensured by two proteins:

Back 22

Titin and nebulin.

Front 23

What is titin?

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The largest protein. It stretches from Z line to M line. It stabilises the length of sacromere

Front 24

Function of nebulin

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Nebulin helps align the actin filaments of the sacromere

Front 25

Muscle tension is

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The force created by contracting muscle

Front 26

Muscle load is

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The force or weight that opposes contraction of the muscle

Front 27

Contraction is...

Back 27

Creating a tension in a muscle that require energy input from ATP

Front 28

Which neurotransmitter is released at neuromuscular junction?

Back 28

Acetylcholine

Front 29

What kind of motor neuron releases ACH at neuromuscular junction?

Back 29

Somatic motor neuron

Front 30

What is excitation-contraction coupling?

Back 30

Is the process in which muscle action potentials initiate calcium signals that in turn activate contraction relaxation cycle

Front 31

What controls the position of an elongated protein polymer Tropomyosin?

Back 31

TROPONIN CONTROLS POSITION OF TROPOMYOSIN

Front 32

What complex pulls away tropomyosin from actin-myosin binding site?

Back 32

The calcium-troponin C complex pulls tropomyosin away from binding site

Front 33

In rigor state myosin head is tightly bound to G-actin molecules and what molecule is bound to myosin??

Back 33

No molecule. No Adp nor atp

Front 34

What atp does to myosin actin complex?

Back 34

Atp decreases the binding affinity and myosin is released

Front 35

After hydrolysis of ATP what first is released?

Back 35

Pi. This allow myosin hwD to swivel

Front 36

What happens to myosin when Adp is released?

Back 36

It is tightly bound to actin in rigor state.

Front 37

4 steps of ex itation-contraction coupling

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1. Acetylcholine released at neuromuscular junction. 2. ACH initiates action potential in muscle fiber. 3.the muscle action potential triggers calcium release from the sacroplasmic reticulum. 4. Calcium combines with troponin and initiates contraction.

Front 38

What is the End Plate Potential?

Back 38

Depolarizatiob at the motor end plate due to acetylcholine.

Front 39

A receptor found only in skeletal muscle that is me hanically linked to Ca++ channels in sacroplasmic reticulum.

Back 39

L-TYPE CALCIUM CHANELL CALLED DHP receptor

Front 40

Calcium release channels in Sacroplasmic reticulum are called

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RyR ryanodine receptors

Front 41

The sacroplasmic reticulum pumps Ca back in using

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Calcium ATPase

Front 42

A single contraction-relaxation cycle in a skeletal muscle fiber is know as a

Back 42

Twich

Front 43

What latent period between muscle action potential and beggining of muscle tension represent?

Back 43

The latek prior represent time required for release of calcium and its binding to troponin

Front 44

The backup source of energy in muscle is

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Phosphocreatine

Front 45

How phosphocreatine is utilised?

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During exercise, the high energy phosphate group of phosphocreatine is quickly transferred to ADP creating more ATP to power the muscles.

Front 46

The enzyme that transfer the phosphate group from phosphocreatine to ADP is know as

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Creatine Kinase CK or Creatine Phosphokinase CPK

Front 47

Elevates levels of which enzymes indicate damage to skeletal/ cardiac muscle?

Back 47

Creatine Kinase. Muscle cells contain a lot of this enzyme.

Front 48

When the oxygen levels fall muscle fiber metabolism relies on

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Anaerobic glycolysis

Front 49

Muscle fibers can obtain energy from fatty acid in the presence of

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Oxygen

Front 50

What is fatigue?

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Fatigue is a reversible condition in which an exercising muscle cannot generate or sustain expected power output anymore.

Front 51

Name types of muscle fibers in relation to their action

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Slow-twitch fibers, fast-twitch oxidative-glycolytic fibers, fast twitch glycolytic fibers.

Front 52

The speed in which muscle contract is determined by

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The isoform of myosin ATPase. Fast twitch fibers split ATP more rapidly than slow twitch fibers

Front 53

Duration of contraction is determined by

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How fast the sacroplasmic reticulum removes Ca from sarcoplasm

Front 54

Which muscle tyle is useful for quick fine movements?

Back 54

Fast twitch fibers. E.g. Eye muscle

Front 55

Which fibers fatigue more easily : glycolytic fibers or oxidative fibers?

Back 55

Glycolytic fibers (fast twitch)

Front 56

A transfer molecule that has high affinity for oxygen. It gives muscle its red colour

Back 56

Myoglobin

Front 57

How oxidative fibers maintain better oxygen supply for ATP production?

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.1)more blood vessels. 2)presence of myoglobin 3) smaller diameter allowing faster diffusion of oxygen to mitochondria

Front 58

What is TETANUS?

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TETANUS is a state of muscle maximal contraction.

Front 59

What is an incomplete/infused tetanus?

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In infused tetanus the stimulation rate off muscle fiber is Not at a maximum value

Front 60

What happens in complete tetanus?

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In fused/complete tetanus the stimulation rate is fast enough that the muscle fiber does not have time to relax.

Front 61

Isotonic contraction is

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Any contraction that creates a force a moves a load

Front 62

Isometric contraction

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Isometric contraction creates a force without a movement

Front 63

What structure is responsible for isometric contraction?

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Elastic elements. They stretch and even up shortening of sacromeres

Front 64

How botunin toxic acts on muscles?

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Botulin toxins decrease the release of ACH

Front 65

Pathogenesis of Duchenne muscular dystrophy

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The protein that links actin to proteins in the cell membrane-the dystrophin is absent. In these fibers, calcium enters through small tears and activates intracellular enzymes resulting in breakdown of the fiber components.

Front 66

True or false : most smooth muscle are single unit muscles.

Back 66

True. Coordinated contraction results by spreading the electrical signal through gap junctions.

Front 67

What determines the force of contraction in smooth muscle?

Back 67

Level of release of calcium from Sr.

Front 68

How a skeletal muscle increase the force of contraction?

Back 68

Recruitment of additional fibers

Front 69

What type of muscle contract and relax fastest andd which one slowest?

Back 69

Skeletal has the shortest twitch(the fastest) and smooth has the longest twitch (longest contraction andd relaxation)

Front 70

Smooth muscle contraction is controlled by.... System

Back 70

Autonomic.

Front 71

True or false:smooth muscle lacks specialised receptor regions such as motor end plate.

Back 71

True. Receptors found all over the surface.

Front 72

Where does calcium come in from in a smooth muscle excitation?

Back 72

Smooth muscle relies on calcium from ECF and SR

Front 73

True or false'smooth muscle has no troponin

Back 73

True.

Front 74

What happens in smooth muscle when calcium is In sarcoplasm?

Back 74

Ca binds to calmodulin (Cam). This Ca-CaM complex activates myosin light chain Kinase MLCK which phosphorylates light chain in myosin heads and increases myosin ATPase activity.

Front 75

True or false-smooth muscle lacks sacromeres

Back 75

True.

Front 76

What protein calcium binds to in a smooth muscle once inside the cell?

Back 76

Calcium bind to Calmodulin. This is the 1st step in cascade.

Front 77

What controls contraction and relaksation in smooth muscle?

Back 77

Phosphorylation and dephosphorylation of myosin light chain

Hint 77

Myosin