Finals | Muscular System Flashcards by Eun Woo

Functions of the muscular system

Producing body movements/ motions
Stabilizing body positions (ex. standing/ sitting)
Storing and moving of substances within the body
Generating heat (Thermogenesis)

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Used to maintain temperature within the body

Thermogenesis

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Signs and symptons of fever which is a mechanism of body to increase heat

Shivering

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Properties of a muscular tissue

Electrical excitability
Contractility
Extensibility
Elasticity

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Ability to respond to certain stimuli by producing electrical signals such as action potential/ impulses

Electrical excitability

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Electrical signals

Action potentials/ impulses

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Action potentials in muscles

muscle action potentials

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Action potentials in nerve cells

nerve action potentials

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Two main types of stimuli trigger action potentials for muscle cells

Electrical signals
Chemical Stimuli

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Arises from muscular tissue itself

Electrical signals

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Example of an electrical signal

Pacemaker

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Send low-energy electrical impulses to control the rate and rhythm of the heartbeat

Pacemaker

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What area of the heartbeat does the pacemaker control?

rate and rhythm

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Neurotransmitters released by neurons, hormones distributed by the blood, or even changes in pH

Chemical stimuli

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What falls under chemical stimuli?

Neurotransmitters released by neurons
Hormones distributed by the blood
Changes in pH

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When skeletal muscle contracts it generates tension while pulling on its attachment points

Contractility

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Motion of flexion

Contractility

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When this contracts, it generates tension while pulling on its attachment points

Skeletal muscle

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Muscle develops tension but does not shorten

Muscle contractions

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Another word for tension

Force of contraction

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Ability to stretch within limits, without being damaged

Extensibility

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The (1) within the muscle, limits the range of extensibility and keeps it within the contractile range of the (2)

connective tissue
muscle cells

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Ability of the muscular tissue to return to its original length and shape after contraction or extension

Elsticity

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Lines the body wall and limbs and supports and surrounds muscles and other organs of the body

Fascia

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Functions of the fascia

1. Lines body walls and limbs 2. Support and surround muscles and other organs

3 layers of connective tissue

1. Epimysium 2. Perimysium 3. Endomysium

Used to surround and protect muscular tissues

Connective tissue

Insulating layer that will reduce heat loss

Triglyceride

Protects the muscle from physical trauma

Triglyceride

Outer later of connective tissue tthat encircle the entire muscle

Epimysium

Surrounds groups of 10-100 or more muscle fiber separating them into bundles called fascicles

Perimysium

The perimysium surrounds groups of (1) or more muscle fibers separating them into (2) called (3)

1. 10-100 2. bundles 3. fascicles

Penetrates the interior of each fascicle and separates individual fiber from one another

Endomysium

Orientation of the coverings/linings of the connective tissue from outer to inner

Triglyceride Fascia Epimysium Perimysium Endomysium

Define tendons

Muscle-to-bone attachment

Example of tendons

Achilles tendon (calcaneal): gastrocnemius muscle (calf)- calcaneus (heel bone)

Connective tissue extend as broad, flat sheet

Aponeurosis

Example of aponeurosis

Epicranial aponeurosis

Where is epicranial aponeurosis found?

Between the frontal and occipital bellies of the occipitofrontalis muscle

Muscle that moves the eyebrow

Frontal belly

Diameter and length of a skeletal muscle fiber

Diameter: 10 to 100 μm Length: 10 cm (4 in), some are 30 cm (12 in)

Fusion of a hundred or more small mesodermal cells

Myoblasts

When does a myoblast arises?

During embryonic development

Myoblast: - Fusion of hundred or more small (1) - Once fusion is done, muscle fiber loses its ability to undergo (2) - Thus, number of (3) is set is set before you are born

1. mesodermal cells 2. cell division 3. skeletal muscle fibers

Outer covering of muscle fiber

Plasma membrane

Plasma membrane of muscle cell

SARCOLEMMA

Thousand of tiny invaginations, tunnels in from the surface towards the center of each muscle fibers.

TRANSVERSE TUBULES

Cytoplasm of the muscle fiber, contains glycogen

SARCOPLASM

What does the sarcoplasm contain?

Glycogen

used for synthesis of ATP

Glycogen

Releases oxygen when it is needed by the mitochondria for ATP production

Myoglobin

Contractile organelles of skeletal muscle

MYOFIBRILS

Myofibrils diameter

(2 μm in diameter)

Fluid-filled system of membranous sacs

SARCOPLASMIC RETICULUM

Dilated ends sacs of sarcoplasmic reticulum

Terminal cisterns

A transverse tubule and 2 terminal cisterns

Triad

What does a triad involve?

Terminal cistern Transverse tubule Terminal cistern

Smaller proteins within the myofibrils

Filaments

Basic functional units of a myofibrils

Sarcomeres

Narrow, plate-shaped regions of dense protein that separates the sarcomeres from the next

Z-Discs

Shape of Z-discs, and what does it separate

Narrow, plate-shaped Separates sarcomeres

Separates 2 thick filaments

I band

A sarcomere extends from one (1) to the (2)

1. Z disc 2. next Z disc

The darker middle part of the sarcomere

A band

One end and another end of the thick filament; end-to-end of a thick filament

A band

Myofibril's entire circumference

M line

Connection of an A band and I band

H zone

Appearance, location, and control of skeletal muscles

Appearance: Striated (cylindrical) Location: Skeletal (connected to bones) Control: Voluntary

Appearance, location, and control of smooth muscles

Appearance: Smooth (non-striated, fusiform) Location: Visceral (Visceral organs) Control: Involuntary

Appearance, location, and control of cardiac muscles

Appearance: Cylindrical, striated, branched Location: Myocardium (cardiac muscle) Control: Involuntary

Ways of the muscle fibers to produce ATP

1. Creatinine Phosphate 2. Anaerobic glycolysis 3. Aerobic glycolysis

Unlike most cells in the body, the ---switch from a low level of activity to a high level of activity (or vice versa)

skeletal muscle fibers

Low level of activity vs high level of activity

Low level of activity: Muscles are relaxed and uses modest amount of ATP High level of activity: Muscles are contracting and uses ATP at a rapid pace

An energy-rich molecule found in muscle fibers

Creatinine Phosphate

Small, amino acid-like molecule (liver, kidneys and pancreas)

Creatinine

Areas where creatinine is synthesized

Liver Kidney Pancreas

Where most abundant creatinine is found

Liver

Pace of the formation of ATP from CP

Rapid: 15 seconds

First source of energy when muscle contraction begins

Creatinine Phosphate

Series of reaction that quickly breaks down each glucose molecule into two molecules of pyruvic acid

Glycolysis

Breakdown of glucose gives rise to (1) when oxygen is (2) or at (3)

1. lactic acid 2. absent 3.low concentration

What gives rise to lactic acid?

Breakdown or glucose

How long does anaerobic glycolysis provide enough energy?

2 minutes

Plays a central role in sugar metabolism

Pyruvic acid

Needs oxygen to convert itself into lactic acid (which is more compatible with anaerobic glycolysis)

Pyruvic acid

Series of oxygen-requiring reaction that produces ATP, CO2, water and heat

Aerobic glycolysis

What does aerobic glycolysis produces?

ATP CO2 Water Heat

Compare aerobic glycolysis to anaerobic glycolysis

Aerobic glycolysis is slower than anaerobic glycolysis but it yields more ATP.

Aerobic respiration provides nearly all of the needed ATP in activities that last for how long?

From several minutes to an hour or more

Types of skeletal muscle fibers

1. Slow Oxidative (SO) Fibers 2. Fast Oxidative-Glycolyctic (FOG) Fibers 3. Fast Glycolytic (FG) Fibers

Largest fibers

Fast Oxidative-Glycolyctic (FOG) Fibers

What do SO Fibers contain ( and color)?

Myoglobin and many blood capillaries (red)

What do FOG fibers contain (and color)?

Large amounts of myoglobin and blood capillaries (red-pink)

What do FG Fibers contain?

Low myoglobin content few blood capillaries few mitochondria (white)

Contains large amount of glycogen

Fast Glycolytic (FG) Fibers

How do the different skeletal muscle fibers generate ATP?

1. SO FIbres: Aerobic respiration 2. FOG Fibers: Anaerobic glycolysis 3. FG Fibers: Glycolysis

Very resistant to fatigue and are capable of prolonged, sustained contractions for many hours

Slow Oxidative (SO) Fibers

SO Fibers twitch contractions

100-200 msec

Example of activity adapted for slow oxidative fibers

Running a marathon

Has high resistance to fatigue

Fast Oxidative-Glycolytic (FOG) Fibers

FOG twitch contractions

less than 10 msec

Example of activity adapted for fast oxidative-glycolytic fibers

Walking and sprinting

Can contract strongly and quickly, but fatigue quickly

Fast glycolytic (FG) fibers

Example of activity adapted for fast glycolytic fibers

Weight lifting or throwing a ball/ strength training programs

Compare the myoglobin content (structural characteristic) of the 3 skeletal muscle fibers

SO: Large amount FOG: Large amount FG: Small amount

Compare the mitochondria (structural characteristic) of the 3 skeletal muscle fibers

SO: Many FOG: Many FG: Few

Compare the capillaries (structural characteristic) of the 3 skeletal muscle fibers

SO: Many FOG: Many FG: Few

Compare the color (structural characteristic) of the 3 skeletal muscle fibers

SO: Red FOG: Red-pink FG: White (pale)

Compare the capacity of the 3 skeletal muscle fibers for generating ATP and the method used (functional characteristic)

SO: High, by aerobic respiration FOG: Intermediate, by both aerobic respiration and anaerobic glycolysis FG: Low, by anaerobic glycolysis

Compare the contraction velocity (functional characteristic) of the 3 skeletal muscle fibers

SO: Slow FOG: Fast FG: Fast

Compare the fatigue resistance (functional characteristic) of the 3 skeletal muscle fibers

SO: High FOG: Intermediate FG: Low

Compare the order of recruitment (functional characteristic) of the 3 skeletal muscle fibers

SO: First FOG: Second FG: Third

Compare locations where the 3 skeletal muscle fibers are abundant (functional characteristic)

SO: Postural muscles such as those of neck FOG: Lower limb muscles FG: Upper limb muscles

Compare the primary functions (functional characteristic) of the 3 skeletal muscle fibers

SO: Maintaining posture and aerobic endurance activities FOG: Walking, sprinting FG: Rapid, intense movements of short duration