Study Guide: Chapter 10 The Muscular System

What is titin?

Structual protein that connects the Z discs to the M line of the sarcomere, stabilizing the position of the thick filament. Gives the elasticity and extensibility of myofibrils.

Regulatory proteins

Switch contraction process on/off

Neuromuscular junction

Synapse between motor neuron and individual muscle fiber

The Connective tissue covering collectively become one forming a __________ to tie unto _________.

TOGETHER-->TENDONS-->ORIGIN and INSERTION

The myosin ____ points towards the M line in the center of the sarcomere

Tail

Muscle belly connects to the ___ which connects to the ____.

Tendon, Bones

Tonic

Tension

Isometric Contraction

Tension generated is not enough to exceed the resistance of the object to be moved Energy is still spent yet no body movement Hold your anatomy text while maintaining your arm and forearm stretched out. Stabilizes joints as others are moved

Extensibility: What is it?

The ability of muscular tissue to stretch within limits without being damaged.

I band

The lighter, less dense area that contains the rest of the thin filaments but no thick filaments. Z disc passes through the center of each I band

This is what makes your muscle so strong. at its junction with the bone, the surface tissue of the tendon is continuous with the _________ while its deeper collagen fibers enter the one to blend with collagen of the _____ ______ ______.

This is what makes your muscle so strong. at its junction with the bone, the surface tissue of the tendon is continuous with the (PERIOSTEUM) while its deeper collagen fibers enter the one to blend with collagen of the (osseous extracellular matrix.)

What type of connective tissues are tendons?

Tough, glistening, white Dense regular connective tissues

What are the qualities of tendons?

Tough, glistening, white. Not very vascularized (little blood vessels), lack muscle cells, and composed mainly of parallel arrangements of collagen protein fibers.

Contractility: What is it?

Upon stimulation via Action Potential contraction occurs which generates tension / force of contraction pulls on attachment points

Skeletal muscle tissue: Voluntary or involuntary?

Voluntary: actions can be consciously controlled with the somatic nervous system

Smooth muscle tissue: Location

Walls of the hollow interal structures like blood vessels, airways, and most organs in the abdominopelvic cavity. Hair follicles in the skin.

____ thin filaments for every _____ thick filaments are in the region of filament overlap

2 thin filaments for every 1 thick filament

How many myosin make up a thick filament?

300 Myosin make up a thick filament.

H zone

A narrow region in the center of each A band that contains thick filaments but no thin filaments

M line

A region in the center of H zone that contains proteins tha thod the thick filaments together at the center of the sarcomere

Synaptic vesicles contain...

ACh =Acetylcholine (neurotransmitter)

Producing heat - As ______ tissue contracts, it produces heat through _________ . Heat is released to maintain normal body __________. ONE METHOD IS...

As (MUSCULAR) tissue contracts, it produces heat through (THERMOGENESIS). Heat is released to maintain normal body (TEMPERATURE) . (SHIVERING)

Endomysium: Binds _____ ______ together yet loose enough to move freely

Binds MUSCLE FIBERS together yet loose enough to move freely

What do myosin heads bind during contraction?

Binds to myosin binding sites on thin filaments during contraction

What are the function of capillaries?

Bring oxygen and nutrients to muscle fibers. Remove heat and waste products of muscle metabolism.

What surrounds muscle fibers and whole muscles, and carry the blood vessels and nerves that exert their effects on individual fibers?

CONNECTIVE TISSUE

Stores/moves substances within the body: Cardiac muscle contraction _______ blood through the body's blood ________

Cardiac muscle contraction (PUMPS) blood through the body's blood (VESSELS)

Smooth muscle tissue: Unique Characteristics

Connective tissue components: Endomysium Contractile proteins NOT organized into sarcomeres very little sarcoplasmic reticulum Transverse tubules NOT present Contain gap junctions in visceral smooth muscle; none in multiunit smooth muscle Autorhythmicity in visceral smooth muscle Source of Ca2+ for contraction: Sarcoplasmic Reticulum and interstitial fluid Considerable regeneration via pericytes compared to other muscle tissues

Cardiac muscle tissue: Unique Characteristics

Connective tissue components: Endomysium, perimysium Contractile proteins organized into sarcomeres SOME sarcoplasmic reticulum Transverse tubules present aligned with each Z disc Intercalated discs contain gap junction and desmosomes Autorhythmicity (beats to own rhythm) Source of Ca2+ for contraction: Sarcoplasmic Reticulum and interstitial fluid Limited regeneration

Skeletal muscle tissue: Unique Characteristics

Connective tissue components: Endomysium, perimysium, epimysium Contractile proteins organized into sarcomeres Abundant sarcoplasmic reticulum Transverse tubules present aligned with each A-I band junction no Junctions between fibers No Autorhythmicity Source of Ca2+ for contraction: Sarcoplasmic Reticulum

Extensibility: What limits the range of muscle tissue?

Connective tissue limits range. keeps it within contractile range.

What are the components of myosin?

Contains a tail and two myosin heads

Myofibrils

Contractile fibers that looks striped (striated)

Epimysium: Wraps all _____ TOGETHER forming the _____ _____

Wraps all FASCICLES together forming the MUSCLE BELLY

Cardiac muscle tissue: Striations?

Yes

Skeletal muscle tissue: Striations?

Yes, because of alternating light and dark protein bands are visible when looking in microscope

Extensibility: Does cardiac muscle stretch?

Yes, every time your heart fills with blood

During muscle contraction, what happens to the z discs during the sliding filament mechanism?

Z discs come closer together

Sarcoplasm

Cytoplasm of a muscle fiber

A band

Dark middle part of the sarcomere that extends the entire length of the thick filaments and the part of the thin filaments that overlap with the thick filaments

Around the periphery of the muscle is a thicker covering of ____ ____ connective tissue called the ________ that binds all the ______ together to form the muscle belly.

Dense Irregular, Epimysium, Fascicles

Terminal Cisterns

Dilated sacs of the sarcoplasmic reticulum that butt up against T tubules. When triggered Ca2+ will be released from the terminal cisterns into the sarcoplasms triggering muscle contraction

Hypertrophy

Dramatic muscle growth occuring after birth. Enlargement of muscle fibers. Increased production of myofibrils, mitochondria, SR, and organelle

Each skeletal muscle is a separate _____ composed of hundreds to thousands of skeletal muscle cells, also called ______ _____ because of their _______ shape

Each skeletal muscle is a separate (ORGAN) composed of hundreds to thousands of skeletal muscle cells, also called (MUSCLE FIBERS) because of their (ELONGATED) shape

Electrical excitability: To main types of stimuli trigger action potentials in muscle cells:

Electrical and chemical stimuli

Where do nerves typically enter the muscle?

Enters via stable tendon (origin)

Fascia

Epimysium, Perimysium, Endomysium

Iso

Equal

Groups of muscle fibers form bundles called _____ and it is covered by a ______ ______ connective tissue covering called the _______________

Fascicle, Dense Irregular, Perimysium

Smooth muscle tissue: Cells

Fiber is thickets in the middle and tapered at each end. Has one centrally positioned nucleus. Not striated.

Perimysium allows freedom of motion between each ______

Freedom of motion between each FASCICLE

During embryonic development, where do muscle fibers arise?

From the fusion of a hundred small mesodermal cells called myoblasts.hence, why each fiber is a single cell with a hundred or more nuclei.

Necrotizing fasciitis

HOMEOSTATIC IMBALANCE. Caused by Streptococcus pyogenes (anaerobic bacteria)

Myosin heads

Head projects outward from the shaft in a spiral ing fashion each extending toward one of the six thin filaments that surround the thick filament.

Cardiac muscle tissue: Function(s)

Heart Contraction responsible for blood circulation

Cardiac muscle tissue: Location

Heart where it forms the heart walls

Triad

1 T tubule and 2 terminal cisterns

What can adjust HR by speeding up or slowing down pacemaker

Hormones and neurotransmitters

What hormones promote muscle enlargement?

Human Growth Hormone and Testosterone

The contraction Cycle

1. ATP hydrolysis 2. Attachment of Myosin to actin forming cross-bridges 3. Power stroke 4. Detachment of myosin from actin

Motor Protein

a protein that convert ATP chemical energy into the mechanical energy of motion to produce force

Electrical excitability: Where do chemical signals arise? Example.

a stimuli released by chemicals to stimulate an action potential. Neurotransmitter released by neurons. hormones distributed by blood. Changes in pH.

Glycogen

a storage molecule containing a lot of linked glucose molecule. For use when a muscle needs energy and all glucose has already been used... it uses glycogen

Muscle action potentials travel...

along the sarcolemma and through the transverse tubules, quickly spreading throughout the muscle fiber

Myofibrils are built from 3 types of proteins. What type are they?

1. Contractile Proteins 2. Regulatory proteins 3. Structural Proteins

The prime function of muscle is...

changing chemical energy into mechanical energy to perform work

Muscular tissues have 4 special properties that enable it to perform its functions and contribute to the homeostasis of your body: these are...

1. Electrical excitability 2. Contractility 3. Extensibility 4. Elasticity

5 Functions of muscular tissue:

1. Producing Body Movements 2. Stabilizes Body Positioning 3. Stores/moves substances within the body 4. Heat Production 5. Facial Expressions

During muscle contraction, what happens to the length of the individual thick and thin filaments?

do not change

Sarcoplasmic Reticulum

fluid filled system of membranous sacs like the smooth ER that encircles each myofibril. In a relaxed muscle fiber the SR stores Ca2+

Sarcomere

functional unit of muscle—contractile unit

Contractile Proteins

generate force during contraction

Hyperplasia

Increase in the number of fibers

What does actin look like?

Individual actin molecules that join together to form an actin filament that is twisted into a helix

Cardiac muscle tissue: Voluntary or involuntary?

Involuntary (Autonomic Nervous System) - contraction and relaxation can not be controlled

What can we attribute to the reddish appearance of skeletal muscles?

It contains a large population of highly vascularized muscles cells in the muscle belly

Skeletal muscle tissue: Cells

Long, cylindrical fiber with many peripherally located nuclei. Unbranched. Striated. Limited capacity for regeneration via satellite cells.

Myosin

Main component of thick filaments and functions as the motor protein of all 3 types of muscle.

Metro

Measure or length

What are Capillaries?

Microscopic blood vessels in muscle tissue. Each muscle fiber is in close contact with one or more of them.

because hypertrophied muscles contain more myofibrils, they in turn have what quality?

More forceful contractions

Skeletal muscle tissue: Location

Most commonly attached by tendons to bones

The ___ fibers initiate the contractile function of muscle cells while the ___ fibers provide a feedback to the nervous system to regulate motor function.

Motor Fibers Sensory Fibers

Structure of a skeletal muscle: A skeletal muscle consists of a ______ _______ connected by ________ to the _________.

Muscle Belly (body), Tendon, Skeleton

Excitation—Contraction Coupling

Muscle action potential propagates along sarcolemma and into the T tubules causes Ca2+ release channels to open Ca2+ flows out of Sarcoplasmic reticuli [Ca2+] HIGH

Once fusion occurs, what happens?

Muscle fibers can't undergo cell division.

The most important components of a skeletal muscle are the

Muscle fibers themselves.

Duchenne's Muscular Dystrophy—Inherited via an X-linked recessive gene

Mutated gene coding for dystrophin—little or none • Sarcolemma tears • Damages plasma membrane / cell die ii. Children in wheelchair by ~12—mostly boys iii. Muscle fibers do not contract therefore they atrophy

On each actin molecule is a ________ _______ ________ where a myosin head can attach.

Myosin Binding Site

Thick fibers are made of

Myosin Filaments

What are the 2 contractile proteins in muscle?

Myosin and Actin

Structural proteins

keep thick/thin filaments in proper alignment, provide elasticity and extensibility to myofibrils, link myofibrils to sarcolemma

What does myosin look like?

looks like 2 golf clubs twisted together.

What does the sarcoplasm contain?

lots of glycogen and myoglobin.

Z discs

narrow plate shaped region of dense protein material that separate one sarcomere from the next.

During muscle contraction, what happens to myosin heads during the sliding filament mechanism?

Myosin heads pull the thin filaments towards the M line

Z discs

Name Number 1

I band

Name Number 2

Thin filament (actin)

Name Number 3

Thick Filament (Myosin)

Name Number 4

M line

Name Number 5

A band

Name Number 6

H zone

Name Number 7

Z discs

Name the component of the sarcomere

Muscle action potentials arise at the..

Neruromuscular Junction

What do the nerves typically enter the muscle as?

Neurovascular bundle (nerve, an artery and one or two veins)

Smooth muscle tissue: named after its unique physical characteristic = Striations? Voluntary or involuntary?

Nonstriated and involuntary (autonomic nervous system)

Multiple ____ are beneath the Sarcolemma

Nuclei

What are all the muscle proteins that are in a sarcomere?

p) Thin=Actin filaments q) Thick=Myosin filaments s) Myosin heads t) Troponin u) Tropomyosin v) Titin

Synapse

region where communication occurs between 2 neurons or a neuron and a target cell.

Describe the nerves in most skeletal muscles such as limbs and the head.

One main nerve that carries motor neurons to the muscle and sensory neurons away from the muscle

Fibrosis

replacement of muscle fibers by fibrous scar tissue limiting the regeneration of skeletal muscle tissue

Since the cells don't physically touch, the action potential can not jump. How does the first cell communicate with the second cell?

Releasing a chemical messenger called neurotransmitter

Surrounding each muscle fiber is thin wrapping of ________ _______ called the _____________

Reticular Fibers, Endomysium

Elasticity is the ability of muscles to do what?

Return to the original length and shape after contraction or extension.

How are the different ways a TENDON can look?

Ropelike, short, or in Flat sheets called APONEUROSIS

What structure releases calcium ions to trigger muscle contraction?

Sarcoplasmic Reticulum

A few myoblasts due persist in mature skeletal muscle as....

Satellite cells

Shortening of the ________ causes shortening of the whole ________ ______ which in turn leads to shortening of the entire _______.

Shortening of the SARCOMERES causes shortening of the whole MUSCLE FIBER which in turn leads to shortening of the entire MUSCLE.

Stores/moves substances within the body: Skeletal muscle move ________ through the body and return ______ from _________ to the heart

Skeletal muscle move (LYMPH) through the body and return (BLOOD) from (VEINS) to the heart

What are the 3 types of muscular tissue?

Skeletal muscle tissue Cardiac muscle tissue Smooth muscle tissue

Filaments or myofilaments

small protein structures within myofibrils

Stores/moves substances within the body: Smooth muscle contraction of _______________ can prevent the outflow of contents in _____________ ______________ LIKE...

Smooth muscle contraction of (SPHINCTERS) can prevent the outflow of contents in (HOLLOW ORGANS). (HOLDING IN PEE OR PROPELLING URINE)

Extensibility: What muscle type stretches the most?

Smooth muscle stretches the most. stomach filling with food

Name the two cells making up the Neuromuscular Junction

Somatic Motor Neuron Muscle Fiber

Nerves stimulating skeletal muscle fibers are known as

Somatic Motor Neurons

Neurons that stimulate skeletal muscle fibers to contract are called...

Somatic Motor Neurons

Where do nerves typically spread to after entering?

Spreads through connective tissue. Spread through the muscle via the connective tissue channels formed by perimysium and endomysium as they wrap the muscle cells.

Stabilizes Body Positioning. Muscular tissue stabilizes _____ to maintain in a body position like....

Stabilizes (JOINTS) to maintain in a body position like keeping your head up

Synaptic cleft

space between two synapses that separate the two cells

What is the purpose of endomysium?

surrounds bind muscle fibers together, but loose enough to allow them to move freely over one another. carries blood vessels that supply the fibers with nutrients.

Sarcolemma (sarc=flesh; -lemma=sheath)

the plasma membrane of the muscle fiber, surrounds its sarcoplasm

Transverse Tubules

tiny invaginations of the sarcolemma that tunnel from the surface to the center of the muscle fiber (filled with interstitial fluid)

Skeletal muscle tissue: Named after its function which is:

to move the bones of the skeleton

______ muscle is found in walls of blood vessels

(SMOOTH) muscle is found in walls of blood vessels

Somatic Motor Neurons have a threadlike extension called a ________ which travels from the neuron _____ _____ in the ______ or _____ _____ to a group of skeletal muscle fibers in a muscle of the body

AXON CELL BODY Brain or Spinal Cord

What is the main component of thin filaments?

Actin

Thin fibers are made of:

Actin filaments

Thin filaments contain what 3 proteins?

Actin, troponin, and tropomyosin

Electrical excitability: both muscle and ____ cells respond to stimuli by producing electrical signals called ______ _______

Action potentials (impulses) MUSCLE ACTION POTENTIALS

During muscle contraction, what happens to the sarcomere during the sliding filament mechanism?

Sarcomere Shortens

What do tendons do?

Attach muscle belly to bone

Autorhythmicity of smooth muscle is due to:

Autonomic division of the nervous system Hormones

Electrical excitability: Where do electrical signals arise? Example.

Autorhythmic electrical signals arise in the muscular tissue itself. Like the heart's pacemaker.

Tails of neighboring myosin molecules lie ____ to one another, forming the shaft of the _____ filament

Parallel. THICK.

Motor endplate

Part of sarcolemma Highly folded area increases ______________ __________ Multiple ACh receptors—What are these receptors?

Electrical excitability: Action potentials travel along a cell's _____ ______ due to the presence of ______ ______

Plasma Membrane Ion Channels

Smooth muscle tissue: Function(s)

Propel food through the GI tract, contractions during birth

Myogloblin

Protein found only in muscle that binds O2 molecules that diffuse into muscle fibers from interstitial fluid. Releases O2 to mitochondia for ATP production.

Sheet like muscles of the body wall have what type of nerves?

Receive multiple nerves that make it possible to independently control different segmental levels within the muscle sheet

Tropomyosin

Regulatory Protein. A part of thin filament. When a skeletal muscle fiber is relaxed, tropomyosin covers the myosin binding site, preventing myosin from binding to actin

Troponin

Regulatory Protein. A part of thin filament. When calcium ions bind to troponin, it undergoes a change in shape which moves tropomyosin away from myosin binding sites. Muscle contraction begins as myosin binds to actin.

Troponin and Tropomyosin are what type of proteins?

Regulatory Proteins