Biology: The Musculoskeletal System

What interconnects lucunae and allows for the exchange of nutrients and wastes between osteocytes and the Haversian and Volkmann's canals? A. Lamellae B. Osteon C. Canaliculi D. Hydroxyapatite

C. Canaliculi

What is the term of the termination point of a long bone? A. Diaphyses B. Metaphyses C. Epiphyses D. Epiphyseal plate

C. Epiphyses

Bones can also be formed via the process by which undifferentiated embryonic connective tissue (mesenchymal tissue) is transformed into, and replaced by bone. This occurs in bones of the skull. What is this process referred to as? A. Chondral Ossification B. Osteochondral Ossification C. Intramembranous Ossification D. Endochondral Ossification

C. Intramembranous Ossification

Which type of muscle is controlled by the autonomic nervous system? A. Skeletal muscle B. Cardiac muscle C. Smooth muscle D. Cardiac and Smooth muscle

D. Cardiac and Smooth muscle Cardiac and Smooth muscle are involuntary

True or False: The vagus nerve provides sympathetic outflow to the heart and raises the heart rate.

False: The vagus nerve provides parasympathetic outflow to the heart and lowers the heart rate.

True or False: An osteocyte is an osteoblast that has become trapped within a bone cavity (lacuna).

True: An osteocyte is an osteoblast that has become trapped within a bone cavity (lacuna).

What muscle types make up the muscular system?

Skeletal muscle Smooth muscle Cardiac muscle

Put the following in order form the start of depolarization to where it spreads: - Bundle of His - Atrioventricular (AV) node - Purkinje fibers - Sinoatrial (SA) node

- SA node - AV node - Bundle of His - Purkinje fibers

Match the following terms: -Z-line -M-line -I-band -H-zone -A-band -Region containing exclusively thin filaments -Region containing exclusively thick filaments -Define the boundaries of each sarcomere -Contains thick filaments in their entirety, including any overlap with thin filaments -Runs down the center of the sarcomere, through the middle of the myosin filaments.

-Z-line -Define the boundaries of each sarcomere -M-line -Runs down the center of the sarcomere, through the middle of the myosin filaments. -I-band -Region containing exclusively thin filaments -H-zone -Region containing exclusively thick filaments -A-band -Contains thick filaments in their entirety, including any overlap with thin filaments

What causes contraction to cease? A. Acetylcholinestrase B. Calcium release ceases C. ATP binds to myosin heads, freeing them from actin D. Myosin-binding sites are covered

A. Acetylcholinestrase Acetylcholine is degraded in the synapse by acetylcholinestrase which results in termination of the signal at the neuromuscular junction and allows the sarcolemma to repolarize. As the signal decays, calcium release ceases, and the sarcoplasmic reticulum takes up calcium from the sarcoplasm. *Without calcium the myosin-binding sites will be covered by tropomyosin and contraction will be prevented.

Put the following structures in the correct category: A. Axial skeleton B. Appendicular skeleton - bones of the limbs (humerus, radius and ulna, carpals, metacarpals, phalanges, femur, fibula and tibia, tarsals, and metatarslas) - Skull - Hyoid bone - Pectoral girdle (scapula and clavicle) - Vertebral column - Pelvis - Rib cage

A. Axial skeleton - Skull - Hyoid bone - Vertebral column - Rib cage B. Appendicular skeleton (typically long bones) - bones of the limbs (humerus, radius and ulna, carpals, metacarpals, phalanges, femur, fibula and tibia, tarsals, and metatarslas) - Pectoral girdle (scapula and clavicle) - Pelvis

What is the shaft of a long bone referred to as? A. Diaphyses B. Metaphyses C. Epiphyses D. Epiphyseal plate

A. Diaphyses

Where is bone derived from? A. Embryonic Mesoderm B. Embryonic Ectoderm C. Embryonic Endoderm D. Blastopore

A. Embryonic mesoderm

Fill in the blank: Each osteon contains concentric circles of bony matrix called __________ surrounding a central microscopic channel. A. Lamellae B. Lacunae C. Canaliculi D. Calcitonin

A. Lamellae Each osteon contains concentric circles of bony matrix called lamellae surrounding a central microscopic channel.

Which makes up the thick filaments of a sarcomere? A. Myosin B. Actin C. Troponin D. Tropomyosin

A. Myosin

What causes myosin to detach from actin? A. New ATP binds to myosin B. New ADP binds to myosin C. ADP and inorganic phosphate dissociates from myosin D. ATP dissociates from myosin

A. New ATP binds to myosin

Put the following under the correct term regarding the bone matrix: A. Organic component B. Inorganic component - peptides - hydroxyapatite crystals - calcium - collagen - glycoproteins - phosphate - hydroxide ions

A. Organic component - collagen - glycoproteins - peptides B. Inorganic component - calcium - phosphate - hydroxide ions - hydroxyapatite crystals * calcium, phosphate, and hydroxide ions harden together to form hydroxyapatite crystals (Ca10(PO4)6(OH)2) *Minerals such as sodium, magnesium and potassium are also stored in bone

Which type of muscle fiber is predominantly found in muscle that contract slowly, but can sustain activity (such as the muscles that support posture)? A. Red Fibers B. White Fibers C. Pink Fibers D. Both A and B

A. Red Fibers Red fibers are also known as Type I fibers. They contain large amounts of myoglobin and have large numbers of mitochondria, so they can efficiently use oxygen to generate ATP through aerobic metabolism. They have a slow contractile velocity, but are very resistant to fatigue. Type II A muscle fibers are also red, but they have a fast contractile velocity. They are resistant to fatigue, but not as resistant as type I fibers. They are oxidative, meaning they use oxygen to generate ATP through aerobic metabolism (medium to moderate ability). However they have high anaerobic metabolism. Type II B muscle fibers are white and they contract rapidly and are capable of generating great force, but they fatigue quickly. They are glycolytic, meaning they use anaerobic metabolism for fuel.

Match the following pertaining to skeletal muscle fibers: - An oxygen carrier that uses iron in a heme group to bind oxygen, imparting a red color - Fast-twitch fibers, contain much less myoglobin -Slow-twitch fibers, have high myoglobin content and primarily derive their energy aerobically A. Red Fibers B. Myoglobin C. White Fibers

A. Red Fibers -Slow-twitch fibers, have high myoglobin content and primarily derive their energy aerobically B. Myoglobin - An oxygen carrier that uses iron in a heme group to bind oxygen, imparting a red color C. White Fibers - Fast-twitch fibers, contain much less myoglobin

What is located just outside of the sarcoplasmic reticulum and is a modified cytoplasm? A. Sarcoplasm B. Transverse tubules (T-tubules) C. Sarcolemma D. Myocytes

A. Sarcoplasm

Which type of muscle is always multinucleated? A. Skeletal muscle B. Cardiac muscle C. Smooth muscle D. Cardiac and Skeletal muscle

A. Skeletal muscle

Which type of muscle is involved in thermoregulation and the movement of fluids in the cardiovascular and lymphatic systems? A. Skeletal muscle B. Cardiac muscle C. Smooth muscle D. Cardiac and Smooth muscle

A. Skeletal muscle Contraction of skeletal muscle produces large amounts of heat. The shivering reflex is the rapid contraction, or shaking, of skeletal muscle to warm the body. The shivering reflex is controlled by the hypothalamus.

Which type of muscle is controlled by the somatic nervous system? A. Skeletal muscle B. Cardiac muscle C. Smooth muscle D. Cardiac and Smooth muscle

A. Skeletal muscle Skeletal muscle is voluntary

Pair the muscle type to its correct description: A. Striated Voluntary Somatic innervation Mulitnucleated Calcium required for contraction B. Nonstriated Involuntary Autonomic innervation 1 nucleus per cell (located in the center of the cell) Calcium required for contraction C. Striated Involuntary Autonomic innervation 1-2 nuclei per cell Connected by intercalated discs that contain many gap junctions Calcium required for contraction -Skeletal muscle -Cardiac muscle -Smooth muscle

A. Skeletal muscle Striated Voluntary Somatic innervation Mulitnucleated Calcium required for contraction C. Cardiac Muscle Striated Involuntary Autonomic innervation 1-2 nuclei per cell Connected by intercalated discs that contain many gap junctions Calcium required for contraction B. Smooth Muscle Nonstriated Involuntary Autonomic innervation 1 nucleus per cell (located in the center of the cell) Calcium required for contraction

Which motor units are activated first? A. Smaller motor units (low threshold motor units (slow-twitch) B. Larger motor units C. High threshold motor units D. A and B

A. Smaller motor units (low threshold motor units (slow-twitch) Smaller motor units are activated first and larger motor units are recruited as needed.

Transverse channels (those with an axis perpendicular to the bone) are called what? A. Volkmann's canals B. Haversian canals C. Osteon canals D. Canaliculi

A. Volkmann's canals

Fill in the blanks: The __________ motor neuron sends a signal from the brain to a __________ motor neuron which signals muscles to start contracting. A. upper, lower B. lower, upper C. upper, upper D. lower, lower

A. upper, lower The upper motor neuron sends a signal from the brain to a lower motor neuron which signals muscles to start contracting.

Which hormone promotes bone formation, lowering blood calcium levels? A. Parathyroid Hormone B. Calcitonin C. Parafollicular Hormone D. Canaliculi

B. Calcitonin Calcitonin is a peptide hormone released by the parafollicular cells (C-cells) of the thyroid in response to high blood calcium levels. Parathyroid hormone is a peptide hormone that is released by the parathyroid gland in response to low blood calcium levels.

Which type of muscle cells are separated from each other by intercalated discs that contain gap junctions? A. Skeletal muscle B. Cardiac muscle C. Smooth muscle D. Cardiac and Smooth muscle

B. Cardiac muscle

Which type of muscle is found only in the heart? A. Skeletal muscle B. Cardiac muscle C. Smooth muscle D. Cardiac and Smooth muscle

B. Cardiac muscle

The action potential of which type of muscle exhibits a plateau after depolarization? A. Skeletal muscle B. Cardiac muscle C. Smooth muscle D. Cardiac and Smooth muscle

B. Cardiac muscle The plateau is created by slow voltage-gated calcium channels, which allow calcium to enter and maintain the inside of the membrane at a positive potential difference. As a result, repolarization of cardiac muscle is slower and more frequent than that of skeletal muscle. The plateau lengthens the time of contraction, preventing a new action potential from starting in the middle of the previous contraction and allowing the heart enough time to refill with blood (preventing tetanus).

Longitudinal channels (those with an axis parallel to the bone) are called what? A. Volkmann's canals B. Haversian canals C. Osteon canals D. Canaliculi

B. Haversian canals

Fill in the blanks: Between the lamellar rings are small spaces called __________, which house mature bone cells called osteocytes. A. Lamellae B. Lacunae C. Canaliculi D. Hydroxyapatite

B. Lacunae Between the lamellar rings are small spaces called lacunae, which house mature bone cells called osteocytes.

What is swellings at the ends of the long bone referred to as? A. Diaphyses B. Metaphyses C. Epiphyses D. Epiphyseal plate

B. Metaphyses

What builds bone? A. Osteocytes B. Osteoblasts C. Osteoclasts D. Osteomasts

B. Osteoblasts Osteoblasts secrete collagen and organic compounds upon which bone is formed. As osteoblasts release bony matrix around themselves, they become enveloped by the matrix and differentiate into osteocytes.

What is the basic contractile unit of skeletal muscle? A. Sacromere B. Sarcomere C. Sarcolemma D. Sacrolemma

B. Sarcomere Sarcomeres are made of thick and thin filaments.

Myofibrils are surrounded by a covering known as what? A. Sarcoplasm B. Sarcoplasmic reticulum C. Sarcolemma D. Myocytes

B. Sarcoplasmic reticulum

Which type of muscle aids in the regulation of blood pressure by constricting and relaxing the vasculature? A. Skeletal muscle B. Smooth muscle C. Cardiac muscle D. B and C

B. Smooth muscle

What does Ca2+ bind to expose the myosin-binding site? A. Tropomyosin B. Troponin C. Myosin D. Actin

B. Troponin Calcium ions bind to troponin triggering a change in confirmation of tropomyosin to which troponin is bound. This change exposes the myosin-binding sites on the actin filament.

Which type of muscle fiber is predominantly found in muscles that contract rapidly, but fatigue quickly? A. Red Fibers B. White Fibers C. Pink Fibers D. Both A and B

B. White Fibers White fibers are also known as type II B fibers - they have low myoglobin content and appear white. They also contain large amounts of glycogen.

The sarcoplasmic reticulum is a modified endoplasmic reticulum that contains a high concentration of which ions? A. Na+ B. Ca+ C. Ca2+ D. K+

C. Ca2+

What provides enough energy for the powerstroke to occur? A. New ATP binds to myosin B. New ADP binds to myosin C. ADP and inorganic phosphate dissociates from myosin D. ATP dissociates from myosin

C. ADP and inorganic phosphate dissociates from myosin It is the dissociation of ADP and Pi from myosin that is responsible for the powerstroke, not the hydrolysis of ATP.

Sarcomeres are attached end-to-end to form what? A. Sarcoplasm B. Myocyte C. Myofibrils D. Muscle fiber

C. Myofibrils Each myocyte, or muscle cell, contains many myofibrils arranged in parallel and can also be called a muscle fiber. muscle fiber = myocyte = muscle cell A muscle is made up of parallel muscle fibers (myocytes/muscle cells) which are composed of parallel myofibrils.

What resorbs bone and is known as the macrophage of the bone? A. Osteocytes B. Osteoblasts C. Osteoclasts D. Osteomasts

C. Osteoclasts *Osteoclasts chew bone Osteoclasts release minerals back into the blood. They are thought to develop from the white blood cells called monocytes.

What is the fibrous sheath that surrounds the long bone to protect it as well as serve as a site for muscle attachment called? A. Endosteum B. Myosteum C. Periosteum D. Epiosteum

C. Periosteum

What is the cell membrane of a myocyte called? A. Sarcoplasm B. Transverse tubules (T-tubules) C. Sarcolemma D. Myocytes

C. Sarcolemma

Which type of muscle contains intermediate filaments, which are attached to dense bodies spread throughout the cell? A. Skeletal muscle B. Cardiac muscle C. Smooth muscle D. Cardiac and Smooth muscle

C. Smooth muscle

Fill in the blanks regarding muscle contraction initiation: Contraction starts at the _________, where the nervous system communicates with muscles via __________. The signal travels down the neuron until it reaches the __________, where __________ is released into the synapse. Acetylcholine binds to receptors on the sarcolemma, causing depolarization. Depolarization triggers an action potential, which spreads down the sarcolemma to the T-tubules. The T-tubules travel into the muscle tissues to the sarcoplasmic reticulum. When the action potential reaches the sarcoplasmic reticulum, __________ is released. These ions bind to __________ triggering a change in confirmation of __________ to which it is bound. This change exposes the __________ on the actin filament. - nerve terminal (synaptic bouton) - Ca2+ - Acetylcholine - Myosin-binding sites - Tropomyosin - Neuromuscular junction - Troponin - Motor (efferent) neurons

Contraction starts at the neuromuscular junction, where the nervous system communicates with muscles via motor (efferent) neurons. The signal travels down the neuron until it reaches the nerve terminal (synaptic bouton), where acetylcholine is released into the synapse. Acetylcholine binds to receptors on the sarcolemma, causing depolarization. Depolarization triggers an action potential, which spreads down the sarcolemma to the T-tubules. The T-tubules travel into the muscle tissues to the sarcoplasmic reticulum. When the action potential reaches the sarcoplasmic reticulum, Ca2+ is released. The calcium ions bind to troponin triggering a change in confirmation of tropomyosin to which troponin is bound. This change exposes the myosin-binding sites on the actin filament.

Which type of muscle is striated? A. Skeletal muscle B. Cardiac muscle C. Smooth muscle D. Cardiac and Skeletal muscle

D. Cardiac and Skeletal muscle

Which type of muscle has myogenic activity? A. Skeletal muscle B. Cardiac muscle C. Smooth muscle D. Cardiac and Smooth muscle

D. Cardiac and Smooth muscle

True or False: Adult human skeletal muscle do not undergo mitosis to create new muscle cells.

True: Adult human skeletal muscle do not undergo mitosis to create new muscle cells.

What does a motor unit consist of? A. A motor neuron B. Muscle fibers C. A motor neuron and some of the muscle fibers it inntervates D. A motor neuron and all of the muscle fibers it innervates

D. A motor neuron and all of the muscle fibers it innervates

What do the free globular heads of the myosin bind to? A. Tropomyosin B. Troponin C. Calcium D. Actin

D. Actin Once Ca2+ binds with troponin and expose the myosin-binding site on actin, myosin heads move toward and bind with actin. The newly formed actin-myosin cross bridges then allow myosin to pull on actin, which draws the thin filaments toward the M-line, resulting in shortening of the sacromere.

Which makes up the thin filaments of a sarcomere? A. Actin B. Troponin C. Tropomyosin D. All of the above

D. All of the above The thin filaments are made of actin along with two other proteins: troponin and tropomyosin. These proteins help to regulate the interaction between the actin and myosin filaments. *To remember which filament is associated with troponin and tropomyosin remember that actin has a T in it.

True or False: All muscle is innervated.

True: All muscle is innervated.

Most bones are created by the hardening of cartilage into bones. What is this process referred to as? A. Chondral Ossification B. Osteochondral Ossification C. Intramembranous Ossification D. Endochondral Ossification

D. Endochondral Ossification Endochondral Ossification is responsible for the formation of most of the long bones of the body.

What is located at the internal edge of the epiphysis? It is a cartilaginous structure and the site of longitudinal growth. A. Diaphyses B. Metaphyses C. Epiphyses D. Epiphyseal plate

D. Epiphyseal plate

The bony matrix is ordered into structural units known as what? A. Osteons B. Lamellae C. Haversian Systems D. A and C

D. Osteons or Haversian Systems

Which type of muscle provides circulatory assistance? A. Skeletal muscle B. Cardiac muscle C. Smooth muscle D. Skeletal and Smooth muscle

D. Skeletal and Smooth muscle Contraction of skeletal muscle helps squeeze blood and lymph through their respective vessels, aiding circulation. In blood vessels, contraction of smooth muscle can constrict the vessel radius, helping to regulate blood flow. In organ walls, it functions to cause contraction of the organ, such as peristalsis in the digestive tract.

Which type of muscle does not need nervous system input in order to maintain rhythmic contractions. A. Skeletal muscle B. Smooth muscle C. Cardiac muscle D. B and C

D. Smooth and Cardiac Muscle Both smooth and cardiac muscle exhibit myogenic activity --- the muscle cells contract directly in response to stretch or other stimuli

During muscle contraction the distance between which lines/bands/zones become smaller and which ones remain constant? -Z-line -M-line -I-band -H-zone -A-band

During muscle contraction the H-zone, I-band, the distance between Z-lines, and the distance between M-lines become smaller, whereas the A-band's size remains constant.

True or False: After death, ATP production ceases and myosin heads can no longer bind to Actin, making it impossible for muscles to relax and lengthen. This condition is known as rigor mortis.

False: After death, ATP production ceases and myosin heads can no longer detach from Actin, making it impossible for muscles to relax and lengthen. This condition is known as rigor mortis.

True or False: All muscle is capable of contraction, which relies on potassium ions.

False: All muscle is capable of contraction, which relies on calcium ions.

True or False: Bone is avascular and innervated.

False: Bone is vascular and innervated.

True or False: Cartilage consists of a firm but elastic matrix called chondrin that is secreted by cells called osteocytes.

False: Cartilage consists of a firm but elastic matrix called chondrin that is secreted by cells called chondrocytes.

True or False: Long bone diaphyses and epiphyses are full of bone marrow.

False: Long bone diaphyses and metaphyses are full of bone marrow. The epiphyses use their spongy cores for more effective dispersion of force and pressure at the joints.

True or False: Motor units are dependent of each other.

False: Motor units are independent of each other.

True or False: Muscle contraction only depends on ATP.

False: Muscle contraction only depends on ATP and Calcium.

True or False: Muscles requiring intricate movements, like those in the fingers, have large motor units.

False: Muscles requiring intricate movements, like those in the fingers, have small motor units.

True or False: Osteoblasts are capable of mitosis.

False: Osteoblasts are incapable of mitosis.

True or False: Osteoclasts are capable of mitosis.

False: Osteoclasts are incapable of mitosis.

True or False: Osteoprogenitor cells are incapable of mitosis.

False: Osteoprogenitor cells are capable of mitosis.

True or False: Compact bone contains red bone marrow, the site of red blood cell development.

False: Spongy bone contains red bone marrow, the site of red blood cell development. Compact bone surrounds a hollow area inside the diaphysis known as the medullary cavity, which holds yellow bone marrow.

True or False: The skeleton is created from only bone.

False: The skeleton is created from two major components: bone and cartilage.

True or False: There is only one supplemental energy reserve in muscle: myoglobin.

False: There are two supplemental energy reserves in muscle: creatine phosphate and myoglobin. Creatine phosphate is created by transferring a phosphate group from ATP to creatine during times of rest. This reaction can then be reversed during muscle use to quickly generate ATP from ADP. Muscle also contain myoglobin, which binds oxygen with high affinity. As exercising muscles run out of oxygen, they use myoglobin reserves to keep aerobic metabolism going.

True or False: Vitamin D helps build bone.

False: Vitamin D resorbs bone. - Vitamin D which is activated by parathyroid hormone promotes the resorption of bone. The resorption of bone in response to vitamin D actually encourages the growth of new, stronger bones

Fill in the blanks: __________ is filled with hematopoietic stem cells, which are responsible for generation of all the cells in our blood; __________ is composed primarily of fat and is relatively inactive. - Yellow marrow - Red marrow

Red marrow is filled with hematopoietic stem cells, which are responsible for generation of all the cells in our blood; yellow marrow is composed primarily of fat and is relatively inactive. *Remember red is for blood and yellow is for fat

Fill in the blanks: __________ attach muscle to bone and __________ attach bone to bone. -Ligaments -Tendons

Tendon attach muscle to bone and ligaments attach bone to bone. *Think: "Ligaments for Like to Like, Tendons for Two Types."

Fill in the blank: The contraction of _________ muscle compresses venous structures and helps propel blood through the __________-pressure venous system towards the heart, as well as lymph through the lymphatic system.

The contraction of skeletal muscle compresses venous structures and helps propel blood through the low-pressure venous system towards the heart, as well as lymph through the lymphatic system.

True or False: A key characteristic of an upper motor neuron injury is muscle spasticity.

True: A key characteristic of an upper motor neuron injury is muscle spasticity. Upper Motor Neurons are responsible for telling the Lower Motor Neurons when to stop contracting. For this reason, if an Upper Motor Neuron is damaged, it won't be able to tell the muscle to stop contracting, resulting in one contraction after another. Another characteristic is muscle weakness, which is also experienced if there is a lower motor neuron injury.

True or False: A protein, titin, acts as a spring and anchors the actin and myosin filaments together, preventing excessive stretching of the muscle.

True: A protein, titin, acts as a spring and anchors the actin and myosin filaments together, preventing excessive stretching of the muscle.

True or False: Cardiac muscle cells are connected by intercalated discs, which contain many gap junctions. These gap junctions are connections between the cytoplasm of adjacent cells, allowing for the flow of ions directly between cells. This allows for rapid and coordinated muscle cell depolarization and efficient contraction of cardiac muscle.

True: Cardiac muscle cells are connected by intercalated discs, which contain many gap junctions. These gap junctions are connections between the cytoplasm of adjacent cells, allowing for the flow of ions directly between cells. This allows for rapid and coordinated muscle cell depolarization and efficient contraction of cardiac muscle.

True or False: Cartilage is avascular and is not innervated.

True: Cartilage is avascular and is not innervated. Bone is vascular and is innervated

True or False: Muscles requiring greater force and less finesse, like those in the back have larger motor units.

True: Muscles requiring greater force and less finesse, like those in the back have larger motor units.

True or False: Norepinephrine from sympathetic neurons or epinephrine from the adrenal medulla binds to adrenergic receptors in the heart, causing an increased heart rate and greater contractility.

True: Norepinephrine from sympathetic neurons or epinephrine from the adrenal medulla binds to adrenergic receptors in the heart, causing an increased heart rate and greater contractility. One of the ways epinephrine does this is by increasing intracellular calcium levels within cardiac myocytes

True or False: Once ATP is bound to myosin causing detachment of myosin from actin, ATP is hydrolyzed to ADP and Pi, which recocks the myosin head so it is in position to initiate another cross-bridge cycle.

True: Once ATP is bound to myosin causing detachment of myosin from actin, ATP is hydrolyzed to ADP and Pi, which recocks the myosin head so it is in position to initiate another cross-bridge cycle.

True or False: Osteocytes are incapable of mitosis.

True: Osteocytes are incapable of mitosis.

True or False: Parathyroid hormone is released by the parathyroid gland in response to low blood calcium and promotes the resorption of bone, increasing the concentration of calcium and phosphate in the blood.

True: Parathyroid hormone is released by the parathyroid gland in response to low blood calcium and promotes the resorption of bone, increasing the concentration of calcium and phosphate in the blood.

True or False: Smooth muscles contain thick and thin filaments, but they are not organized into sarcomeres.

True: Smooth muscles contain thick and thin filaments, but they are not organized into sarcomeres. Smooth muscles contain intermediate filaments and dense bodies. Dense bodies act similar to Z-lines of striated muscle. The thick and thin filaments are attached to the intermediate filaments and then they contract, causeing the intermediates filaments to pull the dense bodies together.

True or False: The depolarization in the muscle is called end plate potential.

True: The depolarization in the muscle is called end plate potential.

True or False: The release of the inorganic phosphate and ADP in rapid succession provides the energy for the powerstroke and results in sliding of the actin filament over the myosin filament.

True: The release of the inorganic phosphate and ADP in rapid succession provides the energy for the powerstroke and results in sliding of the actin filament over the myosin filament.

True or False: The sarcolemma is capable of propagating an action potential and can distribute the action potential to all sarcomeres in a muscle using a system of transverse tubules (T-tubules) that are oriented perpendicularly to the myofibrils.

True: The sarcolemma is capable of propagating an action potential and can distribute the action potential to all sarcomeres in a muscle using a system of transverse tubules (T-tubules) that are oriented perpendicularly to the myofibrils.

True or False: There can be a mixture of both red and white muscle fibers in a muscle.

True: There can be a mixture of both red and white muscle fibers in a muscle.