Anatomy Chapter 10

Aging and muscular tissue: 1.) with aging, there is a progressive decrease in skeletal muscle mass that is replaced by (blank) connective tissue and adipose tissue 2.) this is accompanied by a decrease in maximal strength and slowing of muscle (blank) 3.) in some muscles, there is a change in the proportions of the specific types of skeletal muscle fibers - stringy muscle is sinewy

Aging and muscular tissue: 1.) with aging, there is a progressive decrease in skeletal muscle mass that is replaced by fibrous connective tissue and adipose tissue 2.) this is accompanied by a decrease in maximal strength and slowing of muscle reflexes 3.) in some muscles, there is a change in the proportions of the specific types of skeletal muscle fibers - stringy muscle is sinewy

a (blank) unit consists of a motor neuron plus all the muscle (blank) that it stimulates; all fibers in a motor unit therefore contract and relax simultaneously - the average (blank) unit contains about (blank) muscles but there is a wide range that extends from 2-3 muscle fibers per motor unit to 2000-3000 muscle fibers per (blank) units - small (blank) units provide precise control of movement while large (blank) units provide greater strength of contraction

a motor unit consists of a motor neuron plus all the muscle fibers that it stimulates; all fibers in a motor unit therefore contract and relax simultaneously - the average motor unit contains about 150 muscle fibers but there is a wide range that extends from 2-3 muscle fibers per motor unit to 2000-3000 muscle fibers per motor unit - small motor units provide precise control of movement while large motor units provide greater strength of contraction

cardiac muscle tissue: - forms most of the wall of the (blank) - branches cylindrical and (blank) - (blank) - some cells have (blank) - cells are separated by (blank) discs - regulated by (blank) nervous system and certain hormones - (blank) nucleus per cell

cardiac muscle tissue: - forms most of the wall of the heart - branches cylindrical and striated - some cells have authorhymicity - cells are separated by intercalated discs - regulated by autonomic nervous system and certain hormones - single nucleus per cell

blood vessels called (blank) deliver nutrients and oxygen to muscle fibers and carry wastes and (blank) away from muscle fibers

blood vessels called capillaries deliver nutrients and oxygen to muscle fibers and carry wastes and heat away from muscle fibers

(blank) provide leverage and form the framework of the body, but motion results from alternating (blank) (shortening) and (blank) of muscles

bones provide leverage and form the framework of the body, but motion results from alternating contraction (shortening) and relaxation of muscles

the study of muscles is called (blank)

the study of muscles is called myology

the total number of (blank) muscle fibers and the relative percentages of fast and slow fibers in each muscle do not change significantly after birth, but the characteristics of the muscle fibers present may be somewhat altered in various ways by various types of exercise

the total number of (blank) muscle fibers and the relative percentages of fast and slow fibers in each muscle do not change significantly after birth, but the characteristics of the muscle fibers present may be somewhat altered in various ways by various types of exercise

various skeletal muscles are grouped together and protected by large connective tissue sheets called (blank)

various skeletal muscles are grouped together and protected by large connective tissue sheets called fascia

when a (blank) impulse (action potential) arrives at this junction, the synaptic end bulbs release (blank) (neurotransmitter molecules) [ACh] which diffuse across the synaptic cleft and bind to the (blank) receptor molecules on the junctional folds of the motor (blank) plate; this triggers a muscle (blank) potential that travels along the (blank) and ultimately initiates contraction of the muscle fiber

when a nerve impulse (action potential) arrives at this junction, the synaptic end bulbs release acetylcholine (neurotransmitter molecules) [ACh] which diffuse across the synaptic cleft and bind to the acetylcholine receptor molecules on the junctional folds of the motor end plate; this triggers a muscle action potential that travels along the sarcolemma and ultimately initiates contraction of the muscle fiber

(blank) muscle tissue: 1.) (blank) muscle tissue is located in the wall of the heart 2.) the cells have the following important characteristics: - are (blank) - are (blank) - some cells have (blank) - are branching (blank) that usually contain a single nucleus - neighboring fibers are connected by (blank) discs that contain: (blank) which strongly hold the fibers together and (blank) junctions which allow muscle action potentials to spread from one fiber to another - compared to the skeletal muscle fibers, the sarcoplasm: is more (blank), has larger and more numerous (blank), has a less elaborate (blank) reticulum (SR), and is penetrated by fewer but wider (blank) tubules 3.) under normal resting conditions, cardiac muscle tissue rhythmically contracts and relaxes about (blank) times per minute, this rhythm may be increased or decreased by nerve or hormonal stimulation 4.) (blank) muscle tissue has characteristics that permit significant increases in heart rate but prevent the heart from undergoing (blank) which is a constant state of contraction 5.) cardiac muscle (blank) can undergo hypertrophy in response to increased workload

cardiac muscle tissue: 1.) cardiac muscle tissue is located in the wall of the heart 2.) the cells have the following important characteristics: - are striated - are involuntary - some cells have autorhythmicity - are branching cylinders that usually contain a single nucleus - neighboring fibers are connected by intercalated discs that contain: desmosomes which strongly hold the fibers together and gap junctions which allow muscle action potentials to spread from one fiber to another - compared to the skeletal muscle fibers, the sarcoplasm: is more abundant, has larger and more numerous mitochondria, has a less elaborate sarcoplasmic reticulum (SR), and is penetrated by fewer but wider transverse tubules 3.) under normal resting conditions, cardiac muscle tissue rhythmically contracts and relaxes about 75 times per minute, this rhythm may be increased or decreased by nerve or hormonal stimulation 4.) cardiac muscle tissue has characteristics that permit significant increases in heart rate but prevent the heart from undergoing tetanus which is a constant state of contraction 5.) cardiac muscle fibers can undergo hypertrophy in response to increased workload

muscle tissue has 4 major characteristics that enable it to perform its functions: 1.) electrical (blank) is the ability to respond to certain stimuli by producing electrical signals called action potentials (blank) 2.) (blank) is the ability to shorten, thus developing (blank) (force of contraction) 3.) (blank) is the ability of the muscle to be stretched without being damaged 4.) (blank) is the ability to return to its original shape after contraction or (blank)

muscle tissue has 4 major characteristics that enable it to perform its functions: 1.) electrical excitability is the ability to respond to certain stimuli by producing electrical signals called action potentials (impulses) 2.) contractibility is the ability to shorten, thus developing tension (force of contraction) 3.) extensibility is the ability of the muscle to be stretched without being damaged 4.) elasticity is the ability to return to its original shape after contraction or extension

each skeletal muscle consists of numerous muscle (blank) (muscle cells)

each skeletal muscle consists of numerous muscle fibers (muscle cells)

(blank) glycolytic (FG) fibers or type (blank) fibers: - (blank) in size - most (blank) - appear (blank) due to low concentration of myoglobin - generate ATP by (blank) respiration - contract strong and fast but use ATP quickly - large powerful bursts of (blank) causing them to fatigue early

fast glycolytic (FG) fibers or type II(B) fibers: - large in size - most powerful - appear white due to low concentration of myoglobin - generate ATP by anaerobic respiration - contract strong and fast but use ATP quickly - large powerful bursts of contraction causing them to fatigue early

in the skeletal muscle 3 layers of connective tissue extend from the muscle (blank) and become continuous with the (blank): - the (blank) surrounds the muscle - the (blank) surrounds fascicles (bundles of muscle fibers) - the outer (blank) encircles individual muscle fibers

in the skeletal muscle 3 layers of connective tissue extend from the muscle belly and become continuous with the tendon: - the endomysium surrounds the muscle - the perimysium surrounds fascicles (bundles of muscle fibers) - the outer epimysium encircles individual muscle fibers

muscle (blank) is sustained, partial state of contraction that gives firmness to a relaxed skeletal muscle; in a constantly shifting pattern, a few motor units become active while others become inactive within a skeletal muscle - this is essential for maintaining (blank) - a muscle becomes (blank) upon loss of muscle tone

muscle tone is sustained, partial state of contraction that gives firmness to a relaxed skeletal muscle; in a constantly shifting pattern, a few motor units become active while others become inactive within a skeletal muscle - this is essential for maintaining posture - a muscle becomes flaccid upon loss of muscle tone

(blank) tissue also stabilizes the body's position, regulates (blank) volume, generates (blank), and propels fluids and food through various body systems

muscular tissue also stabilizes the body's position, regulates organ volume, generates heat, and propels fluids and food through various body systems

microscopic anatomy of a skeletal muscle fiber: - during embryonic development, a skeletal muscle fiber is formed by the fusion of (blank) and thus the muscle fibers are (blank)

microscopic anatomy of a skeletal muscle fiber: - during embryonic development, a skeletal muscle fiber is formed by the fusion of myoblasts and thus the muscle fibers are multinucleate

microscopic anatomy of a skeletal muscle fiber: - each muscle fiber has a (blank) (plasma membrane which lies deep to the endomysium) that surrounds the (blank) (cytoplasm); the latter contains an oxygen binding protein called (blank) which gives muscle its red color

microscopic anatomy of a skeletal muscle fiber: - each muscle fiber has a sarcolemma (plasma membrane which lies deep to the endomysium) that sound the sarcoplasm (cytoplasm); the latter contains an oxygen binding protein called myoglobin which gives muscle its red color

muscle tissue has 4 main functions: 1.) producing (blank) 2.) stabilizing (blank) 3.) (blank) and (blank) substances within the body 4.) producing (blank)

muscle tissue has 4 main functions: 1.) producing body movements 2.) stabilizing body position 3.) storing and moving substances within the body 4.) producing heat

- in each skeletal muscle typically a muscle (blank) (body) is attached to bones by (blank) - a (blank) is a cord of dense connective tissue that attaches a muscle to the (blank) of the bone - some tendons are (blank): a broad flat sheet of connective tissue that attaches a muscle to the (blank) of a bone, another muscle, or the skin - an origin is (blank) and an insertion is (blank) - in the biceps brachii an example of an origin is the (blank) and the insertion would be the (blank)

- in each skeletal muscle typically a muscle belly (body) is attached to bones by tendons - a tendon is a cord of dense connective tissue that attaches a muscle to the periosteum of the bone - some tendons are aponeuroses: a broad flat sheet of connective tissue that attaches a muscle to the periosteum of a bone, another muscle, or the skin - an origin is immovable and an insertion is movable - in the biceps brachii an example of an origin is the scapula and the insertion would be the radius

- nerves typically enter a muscle with the main blood vessels of the muscle as a unit called a (blank) bundle - somatic (blank) neurons send impulses down their (blank) to stimulate muscle fibers to contract - the junction or (blank) between a motor neuron and a skeletal muscle fiber is called a (blank) junction (NMJ); these two never actually touch there is a small gap between them called the (blank) cleft

- nerves typically enter a muscle with the main blood vessels of the muscle as a unit called a neurovascular bundle - somatic motor neurons send impulses down their axons to stimulate muscle fibers to contract - the junction or synapse between a motor neuron and a skeletal muscle fiber is called a neuromuscular junction (NMJ); these two never actually touch there is a small gap between them called the synaptic cleft

contraction and relaxation of skeletal muscle fibers: 1.) muscle (blank) is triggered when a muscle action (blank) is propagated along the (blank) through the (blank) tubule system and to the (blank) reticulum (SR), where it causes the release of calcium ions from the SR into the cytosol 2.) muscle contraction occurs via (blank) filament mechanism, in the presence of (blank) and calcium ions, myosin heads attach to (blank) molecules to form crossbridges which pull thin filaments toward the center of the (blank), resulting in the shortening of the sarcomere 3.) the effect of acetylcholine is brief because it is rapidly broken down by (blank) (AChE) located in the synaptic cleft

contraction and relaxation of skeletal muscle fibers: 1.) muscle contraction is triggered when a muscle action potential is propagated along the sarcolemma through the transverse tubule system and to the sarcoplasmic reticulum (SR), where it causes the release of calcium ions from the SR into the cytosol 2.) muscle contraction occurs via sliding filament mechanism, in the presence of ATP and calcium ions, myosin heads attach to actin molecules to form crossbridges which pull thin filaments toward the center of the sarcomere resulting in the shortening of the sarcomere 3.) the effect of acetylcholine is brief because it is rapidly broken down by acetylcholinerase (AChE) located in the synaptic cleft

microscopic anatomy of a skeletal muscle fiber: - growth of a skeletal muscle fiber is achieved primarily by (blank) (increase in size) because skeletal muscle fibers do not significantly increase in number (blank) after birth; skeletal muscle tissue does have limited powers of (blank) due to the presence of satellite cells which can fuse with or replace existing skeletal muscle fibers to a limited extent - if significant skeletal muscle damage or degeneration occurs, skeletal muscle tissue undergoes (blank), the replacement of muscle fiber by fibrous scar tissue - the opposite of hypertrophy is (blank) which means to shrivel up or shrink in size

microscopic anatomy of a skeletal muscle fiber: - growth of a skeletal muscle fiber is acheived primarily by hypertropy (increase in size) because skeletal muscle fibers do not significantly increase in number (hyperplasia) after birth; skeletal muscle tissue does have limited powers of regeneration due to the presence of satellite cells which can fuse with or replace existing skeletal muscle fibers to a limited extent - if significant skeletal muscle damage or degeneration occurs, skeletal muscle tissue undergoes fibrosis, the replacement of muscle fiber by fibrous scar tissue - the opposite of hypertrophy is atrophy which means to shrivel up or shrink in size

microscopic anatomy of a skeletal muscle fiber: - the sarcoplasm contains numerous (blank); a.) the (blank) contain numerous parallel (blank) filaments called (blank) filaments and (blank) filaments that are arranged in functional units called (blank) b.) adjacent sarcomeres are separated by (blank) and have regions called the (blank) band, (blank) band, (blank) zone, (blank) line, and a zone of overlap c.) thick filaments consist of motor proteins called (blank) molecules with heads d.) thin filaments consist of (blank) molecules plus two regulatory proteins called troponin and tropomyosin e.) sarcomeres also contain (blank) proteins (e.g. titin, myomesin, and dystrophin) which keep the thick and thin filaments properly aligned, give the (blank) elasticity and extensibility and link the myofibrils to the sarcolemma and extracellular matrix

microscopic anatomy of a skeletal muscle fiber: - the sarcoplasm contains numerous myofibrils; a.) the myofibrils contain numerous parallel (protein) filaments called thin and thick filaments that are arranged in functional units called sarcomeres b.) adjacent sarcomeres are separated by z-discs and have regions called the A band, I band, H zone, M line, and a zone of overlap c.) thick filaments consist of motor proteins called myosin molecules with heads d.) thin filaments consist of actin molecules plus two regulatory proteins called troponin and tropomyosin e.) sarcomeres also contain structural proteins (e.g. titin, myomesin, and dystrophin) which keep the thick and thin filaments properly aligned, give the myofibril elasticity and extensibility and link the myofibrils to the sarcolemma and extracellular matrix

microscopic anatomy of a skeletal muscle fiber: - the (blank) contains the (blank) reticulum (SR) with dilated end sacs called (blank) cisterns which store (blank) ions; release of (blank) ions into the cytosol triggers muscle (blank) - the sarcolemma has tunnel-like infoldings called (blank) tubules (T tubules) that penetrate into the muscle fiber at right angles to the myofilaments; these T tubules conduct muscle (blank) which cause the release of calcium ions from the SR - triad: two terminal (blank) and one (blank) tubule

microscopic anatomy of a skeletal muscle fiber: - the sarcoplasm contains the sarcoplasmic reticulum (SR) with dilated end sacs called terminal cisterns which store calcium ions; release of calcium ions into the cytosol triggers muscle contraction - the sarcolemma has tunnel-like infoldings called transverse tubules (T tubules) that penetrate into the muscle fiber at right angles to the myofilaments; these T tubules conduct muscle action potentials which cause the release of calcium ions from the SR - triad: two terminal cisterns and one transverse tubule

skeletal muscle fibers are not all identical in structure or function: 1.) muscle fibers that have a high content of (blank), a red oxygen storing protein (as well as more mitochondria and a rich blood supply) are called (blank) muscle fibers 2.) muscle fibers that have low content of (blank) are called (blank) muscle fibers 3.) based on structural and functional characteristics, skeletal muscle fibers are classified into 3 types: - (blank) oxidative (SO) fibers or type I fibers - (blank) oxidative-glycolytic (FOG) fibers or type II(A) fibers - (blank) glycolytic (FG) fibers or type II(B) fibers 4.) most skeletal muscles contain a mixture of all 3 types of skeletal muscle fibers, but their proportion varies depending on the usual action of the muscle; however, the muscle fibers in any one motor unit are all of the same type

skeletal muscle fibers are not all identical in structure or function: 1.) muscle fibers that have a high content of myoglobin, a red oxygen storing protein (as well as more mitochondria and a rich blood supply) are called red muscle fibers 2.) muscle fibers that have low content of myoglobin are called white muscle fibers 3.) based on structural and functional characteristics, skeletal muscle fibers are classified into 3 types: - slow oxidative (SO) fibers or type I fibers - fast oxidative-glycolytic (FOG) fibers or type II(A) fibers - fast glycolytic (FG) fibers or type II(B) fibers 4.) most skeletal muscles contain a mixture of all 3 types of skeletal muscle fibers, but their proportion varies depending on the usual action of the muscle; however, the muscle fibers in any one motor unit are all of the same type

skeletal muscle tissue: - moves (blank) (and in some cases skin or other soft tissues) - cylindrical and (blank) - primarily (blank) - [blank]-nucleate

skeletal muscle tissue: - moves bones (and in some cases skin or other soft tissues) - cylindrical and striated - primarily voluntary - multinucleate

(blank) oxidative (SO) fibers or type (blank) fibers are: - (blank) in size - (blank) powerful - dark red (high concentration of [blank]) - large mitochondria (develops ATP through [blank] cellular respiration - uses ATP slowly so they have a slow rate of contraction and are resistant to (blank)

slow oxidative (SO) fibers or type (blank) fibers are: - small in size - least powerful - dark red (high concentration of [myoglobin) - large mitochondria (develops ATP through aerobic cellular respiration - uses ATP slowly so they have a slow rate of contraction and are resistant to fatigue

(blank) oxidative-glycolytic (FOG) fibers or type (blank) fibers: - (blank) in size - dark red in color but not as red as (blank) oxidative fibers - uses ATP fast, so they have an increased rate of (blank)

slow oxidative-glycolytic (FOG) fibers or type II(A) fibers: - intermediate in size - dark red in color but not as red as slow oxidative fibers (SO) - uses ATP fast, so they have an increased rate of contraction

smooth muscle tissue: - located in the walls of hollow internal structures (and [blank] pili muscles) - (blank) (i.e smooth) - (blank) - (blank) shaped - some cells have (blank) - regulated by (blank) nervous system and certain hormones - (blank) nucleus in each cell

smooth muscle tissue: - located in the walls of hollow internal structures (and arrector pili muscles) - nonstriated (i.e smooth) - involuntary - spindle shaped - some cells have autorhythmicity - regulated by autonomic nervous system - single nucleus in each cell

(blank) muscle tissue: 1.) (blank) muscle tissue is usually activated involuntary 2.) there are two types of smooth muscle tissue: - (blank) (single-unit) smooth muscle tissue which is the more common type which is located in the walls of small (blank) vessels and hollow viscera. It is (blank); due to presence of (blank) junctions, entire muscle contracts as a single unit when one fiber is stimulated by a (blank), hormone, or autorhythmic signal - (blank) smooth muscle tissue which is located in the walls of large (blank), bronchioles, arrector (blank) muscles, irises of the eyes, and ciliary muscles of the (blank). Each fiber contracts (blank) upon stimulation 3.) the cells have the following important characteristics - are narrow (blank) with two tapering (blank) - have a (blank) nucleus - the sarcoplasm: contains both (blank) and (blank) filaments but they are not arranged into orderly (blank), i.e. nonstriated and therefore called (blank). also contains (blank) filaments attached to dense bodies 4.) when a smooth muscle fiber contracts it turns like a (blank) 5.) compared to skeletal muscle, contraction starts more (blank) and lasts much longer 6.) the prolonged presence of (blank) ions in the cytosol provides for (blank) muscle tone

smooth muscle tissue: 1.) smooth muscle tissue is usually activated involuntary 2.) there are two types of smooth muscle tissue: - visceral (single-unit) smooth muscle tissue which is the more common type which is located in the walls of small blood vessels and hollow viscera. It is autorhythmic; due to presence of gap junctions, entire muscle contracts as a single unit when one fiber is stimulated by a neurotransmitter, hormone, or autorhythmic signal - multiunit smooth muscle tissue which is located in the walls of large arteries, bronchioles, arrector pili muscles, irises of the eyes, and ciliary muscles of the eyes. Each fiber contracts individually upon stimulation 3.) the cells have the following important characteristics - are narrow fibers with two tapering ends - have a single) nucleus - the sarcoplasm: contains both thin and thick filaments but they are not arranged into orderly sarcomeres, i.e. nonstriated and therefore called smooth. Also contains intermediate filaments attached to dense bodies 4.) when a smooth muscle fiber contracts it turns like a corkscrew 5.) compared to skeletal muscle, contraction starts more slowly and lasts much longer 6.) the prolonged presence of calcium ions in the cytosol provides for smooth muscle tone

there are 2 major types of contraction: 1.) in an (blank) contraction, tension remains almost constant while the muscle changes in length there are two subtypes: a.) in a concentric (blank) contraction, the tension overcomes the resistance and the muscle (blank) b.) in an eccentric isotonic contraction, tension slows the lengthening of the muscle so that the muscle (blank) as it contracts 2.) in an (blank) contraction, a muscle develops tension but does not (blank) because the tension is not great enough to exceed the resistance

there are 2 major types of contraction: 1.) in an isotonic contraction, tension remains almost constant while the muscle changes in length there are two subtypes: a.) in a concentric isotonic contraction, the tension overcomes the resistance and the muscle shortens b.) in an eccentric isotonic contraction, tension slows the lengthening of the muscle so that the muscle lengthens as it contracts 2.) in an isometric contraction, a muscle develops tension but does not shorten because the tension is not great enough to exceed the resistance

there are 3 types of muscle tissue: - (blank) muscle tissue - (blank) muscle tissue - (blank) muscle tissue

there are 3 types of muscle tissue: - skeletal muscle tissue - cardiac muscle tissue - smooth muscle tissue