Muscular System Pt. 2 Flashcards

What is ATP?

Adenosine triphosphate is an energy source the body uses to power muscles

What are the 3 main methods of ATP production?

ATP-PC System, Anaerobic Glycolysis, and Aerobic Pathway

What does PC stand for?

Phosphocreatine

Why does the body need more ATP to complete muscle movements?

Stored ATP in the muscles starts a contraction, is depleted, and now needs more ATP to continue

Glyco means ______ and lysis means ______

sugar ; breakdown

Anaerobic glycolysis

The breakdown of sugar without oxygen

What determines which ATP method is used?

Intensity and duration of physical activity

What starts the muscle contraction?

Stored ATP

What is ATP-PC short for?

adenosine triphosphate-phosphocreatine

What type of energy supplies powerful short-term energy?

ATP-PC

ADP is ____

Not energy

ATP is ____

Energy

What does creatine phosphate break down into?

Creatine, a phosphate group, and energy

Where is glycogen found?

Muscle cells

Creatine Phosphate (definition)

a high-energy molecule stored only in muscle cells that can add another phosphate group to ADP

Where is creatine phosphate found?

Muscle cells

How does the ATP-PC System add another phosphate group to the ADP?

With creatine phosphate

What breaks down creatine phosphate?

What does ADP combine with to make ATP?

a Phosphate group

What is ATPase?

an enzyme used to combine the extra phosphate from the creatine phosphate with the ADP

What does the ATP creation pathway not require?

Oxygen

The extra phosphate from the creatine phosphate breakdown….

combines with ADP to create a new ATP molecule

What is the next source of energy after the ATP-PC System is depleted?

Anaerobic glycolysis

How long does anaerobic glycolysis last?

~2 min

When does anaerobic glycolysis experience a dip in power?

45 sec

Anaerobic

no oxygen is involved

Glycolysis

the breakdown of glucose into ATP

Glucose

a simple sugar

Motor unit

A group of a single motor neuron and the muscle fibers it stimulates

Where do motor neurons live?

Spinal cord

Axon terminals are…

scattered to the muscle fibers

Axons extend to…

Muscle

Neuron (definition)

nerve cell

Elasticity

muscle”s ability to return to its original length

Extensibility

muscles ability to stretch or extend

Contractility

muscles ability to contract forcefully

Excitability

a muscles ability to respond to stimuli

What triggers muscle movement?

Nerve impulse

Describe the Aerobic Pathways Power and Fuel source

It doesn’t produce as much power as the other two systems, but its fuel source is large and takes a long time to run out

Function of the aerobic pathway system

Allows a person to perform activities that require more endurance

Why dont muscles become acidic after the Electron Transport Chain?

Hydrogen ions are removed in the water by-product

Resultants of the Electron Transport Chain

• 34 ATP molecules and water as a by-product

In the Krebs cycle, acetyl coenzyme A is broken down into…..?

carbon dioxide which is expelled through breathing and hydrogen ions which are used in the next step

Acetyl coenzyme A (function)

Allows the energy system to continue breaking down glucose into energy

What substance is produced in aerobic glycolysis?

acetyl coenzyme A

The _______ pathway uses _____ which can fix the ______ problem caused by the hydrogen ions

aerobic; oxygen; acidity

Lactate temporarily ______ and ______

reduces acid buildup; stops ATP production

The body creates _____ to correct the acidic environment

lactate

______ cause muscles to become more acidic

Hydrogen ions

By-product of anaerobic glycolysis

hydrogen ions

ATP molecules used to fuel the glycolysis process go through several transformations and produce _________ and _________

pyruvate and hydrogen ions

What does the body do with extra glucose?

Form glycogen to later be stored in the muscles

Pyruvate

a protein the body produces

Steps of the aerobic pathway

Aerobic glycolysis, Krebs Cycle, Electron Transport Chain

Anaerobic Glycolysis System Steps

Glycogen is converted into glucose, The two ATP in the glucose break down into two ADP and two phosphates, Four ATP molecules are created, Two ATP are used for glycolysis fuel and two are for muscle contraction

Anaerobic glycolysis (formal)

a complex conversion of glucose to lactate when oxygen is NOT available

How many molecules of ATP is in 2 glucose molecules

4 molecules

When glycogen is broke down, what do we get?

2 glucose molecules

What is the TOTAL amount of energy the ATP-PC System lasts?

~10-20 sec

How long does the breakdown of creatine phosphate last?

~5-8 sec

How long does the INITIAL ATP-PC energy last?

~6-15 sec

What are the 3 things you need for a muscle to contract?

Energy System, Nerve Impulse, Action Potential

Sarcolemma

a plasma membrane beneath the endomysium

Primary Function of the Sarcolemma

to help with the absorption of calcium that is required for muscle contraction

Neuromuscular junctions

junctions formed by the axon terminals of the motor unit with the sarcolemma in various muscles

Interstitial fluid

allows the neurotransmitter involved in the impulse to work and is found  in the synaptic cleft

Acetylcholine (Ach)

a neurotransmitter located in vesicles of the axon terminal at the neuromuscular junction

Another word for impulse is…

Action Potential

What are the three that start a muscle contraction?

Energy Systems, Nervous System, Action Potential

Step 1 of Action Potential Sequence

A nerve impulse travels to the axon terminals of the muscle

Step 2 of Action Potential Sequence

Calcium channels open, allowing calcium to enter the axon terminal

Step 3 of Action Potential Sequence

The presence of calcium causes the release of the enzyme

Step 4 of Action Potential Sequence

ACh (acetylcholine) spreads across the synaptic cleft and attaches to receptors on the sarcolemma

Step 5 of Action Potential Sequence

The ACh (acetylcholine) opens channels in the sarcolemma, allowing sodium (Na+) and potassium (K+) ions to build up in muscle fibers, changing the electrical charge

In Step 5 of the Action Potential Sequence, the change in electrical charge __ and __

triggers myosin and actin to use ATP which is later broken down into ADP ; produces an electrical current or the Action Potential

Step 6 of Action Potential Sequence

AChE (acetylcholinesterase) breaks down the ACh (acetylcholine) in the synaptic cleft, causing the sarcolemma channels to close, stopping muscle fiber contraction

One nerve impulse produces…

one contraction

Muscle cells (myocytes) are also called

muscle fibers

Myocyte Shapes

long and cylindrical

Fascicle

several bundles of individual muscle fibers

What is each fascicle wrapped?

Connective Tissue

Epimysium

a tough outer coat that extends past the muscles tapered end and blends into the tendon, wrapping the skeletal muscle

Perimysium

wraps the muscle fascicles

Endomysium

wraps individual muscle fibers

Mitochondria

part of the cell that produces energy

Skeletal muscle characteristics

striated, multinucleated, 2-3x more mitochondria organelles

Organelle

a subunit within a cell that has a specific function

Sarco-

flesh

Sarcolemma

a plasma membrane that wraps the muscle fibers

Sarco- Lemma-

flesh sheath

Organelles of Muscle Cells/Myocytes

Sarcoplasm, Sarcoplasmic reticulum, Myofibrils

Sarcoplasm

liquid that fills the muscle fiber and is made mostly of water, salts, and proteins

3 Functions of Sarcoplasm

hold inner contents of muscle fibers together, protecting it from damage, allows for chemical reactions to occur, allows for organelle operation

Myofibril

a bundle or group of smaller thread-like fibers called myofilaments

Sarcoplasmic Reticulum

a net-like structure that surrounds each myofibril

Sarcoplasmic Reticulum Function

storing and releasing calcium from the muscle fiber

Myofilaments

thread-like fibers found bundled in the myofibril

Two Types of Myofilament

Thick and thin

Myosin

thick myofilament protein

Actin

thin myofilament protein