BIO 151 WileyPlus 6 & 7

The sarcomere consists of

-actin -myosin -Troponin

The general functions of muscle tissue include:

-production of body movement. -stabilization of body positions. -storage and movement of substances through the body. -heat generation.

Which portion of this myogram shows a single twitch of the muscle?

A

Which structure in the image below represents an osteon, the structural unit of compact bone?

A

Which of the following statements is incorrect? -The skeleton provides a structural framework for the body. -The cranium, rib cage and vertebrae protect important internal organs from injury. -Bone releases minerals as needed to maintain homeostasis. -Bone stores calcium and phosphorus. -All of these statements are correct.

All of these statements are correct.

A skeleton that exhibits a partially closed epiphyseal plate would likely be that of a:

An adolescent

Which of the structures in the image below represents concentric lamellae, the layers of mineralized extracellular matrix in bone tissue?

B

Describe bone calcium levels

Blood calcium levels increase when bone breaks down, and decreases when bone is built.

What is the function of an osteoblast?

Bone deposition

Which region of a sarcomere contain thin filaments?

Both I band and A band.

At the end of contraction, the sarcomere returns to its relaxed position when

Calcium pumps remove calcium ions from the sarcomere and put them back into storage in the sarcoplasmic reticulum.

When an athlete performs a pull up (raising their chin to a bar while their body hangs), the process of pulling the body up so the chin can touch the bar is

Concentric

Bone is a type of ________ because it contains an extracellular matrix that surrounds widely spaced cells.

Connective tissue

From most to least, the extracellular matrix of bone tissue contains

Crystallized mineral salts, collagen, water

The shaft of a long bone is called the ________ and the end of a long bone nearest the point of attachment to the trunk is called the _____.

Diaphysis; proximal epiphysis

Muscular tissue has several important properties, such as electrical excitability. Another property of muscular tissue is that it is able to return to its original size and shape after being stretched. Which property of muscular tissue is this?

Elasticity

ATP is hydrolyzed by the myosin tail.

False

Calcitonin is produced by the parathyroid gland.

False

In primary ossification, the first type of bone that forms and replaces the cartilage model is compact bone.

False

Once formed, bone is never broken down.

False

Osteons are composed of concentric rings and are found in spongy bone.

False

Parathyroid hormone (PTH) decreases blood Calcium.

False

The sheet or broad band of fibrous connective tissue that supports and surrounds muscles and other organs of the body is called

Fascia

Which of the following statements is/are incorrect? -Greenstick fractures most commonly occur in elderly people. -An impacted fracture would involve forcing of one end of a fractured bone into the interior of the other end. -A comminuted fracture involves breaking the bone in large and small fragments. -Fracture repair begins with formation of a fracture hematoma. -The final phase of fracture repair is bone remodeling.

Greenstick fractures most commonly occur in elderly people.

What region will narrow or disappear during muscle contraction?

H zone

Name the tissue used as a template during endochondral ossification.

Hyaline cartilage

Where does a primary ossification center form?

In the diaphysis

Most of the bones of the skull are formed by this process.

Intramembranous ossification

Bone remodeling:

Involves replacement of old bone tissue with new bone tissue, bone resorption, bone deposition, osteoclasts and osteoblasts

Which of the following statements is INCORRECT? -Concentric isotonic contractions result in muscle shortening. -Eccentric isotonic contractions result in controlled lengthening of the muscle. -Isometric contractions result in lengthening or shortening of the muscle and moving a load E large motor unit. -In isometric contractions, the tension generated is not great enough to move the load.

Isometric contractions result in lengthening or shortening of the muscle and moving a load E large motor unit.

The all of the following are part of the bone matrix except: -Collagen -Muscle fibers -Hydroxyapatite -Calcium and Phosphorus crystals

Muscle fibers

What causes actin to slide toward the center of the sarcomere?

Myosin heads form a cross-bridge with actin. When the myosin head bends it moves the actin toward the center of the sarcomere.

By what process does the motor neuron stimulate the muscle cell?

Neurotransmitter is released into the synaptic cleft to cause an action potential in the muscle cell.

The type of bone fracture characterized by the broken ends of the bone protruding through the skin is known as a(n)

Open (compound) fracture

PTH will increase ________activity while Calcitonin will decrease __________activity.

Osteoclast; osteoclast

Which of the following do not descend from mesenchyme cells?

Osteoclasts

The coating around bones is called the

Periosteum

Hematopoiesis takes place in the ________ of some adult bones.

Red bone marrow

Providing the calcium and ATP levels remain high in the sarcoplasm, the contraction ____________.

Shortens the sarcomeres of muscle fibers

Which of the following is mismatched? -Periosteal arteries - supply the periosteum and outer part of the bone. -The nutrient arteries enter through Volkmann's canals and supply the inner and outer part of the bone. -Metaphyseal arteries help to supply the red bone marrow and tissue of the metaphysis. -Epiphyseal arteries supply the epiphysis red bone marrow and tissue.

The nutrient arteries enter through Volkmann's canals and supply the inner and outer part of the bone.

Which structure allows the propagation of the muscle action potential?

Transverse tubules

A single action potential will create a single momentary contraction, not a continuous contraction.

True

As long as the levels of calcium and ATP inside the cell are adequate then the contraction cycles will repeatedly occur.

True

Bone remodeling, especially bone resorption, plays a role in the maintenance of proper levels of calcium in the blood.

True

Calcitonin (CT) decreases blood Calcium.

True

Osteoblasts come from mesenchymal precursor cells.

True

The function of the neurotransmitter is to cause the opening of sodium channels in the muscle cell membrane.

True

While bone grown in length involves the epiphyseal plate, bone growth in thickness involves deposition of bone on the outside and removal of bone from the inside.

True

What vitamin is needed for calcium and phosphorus absorption?

Vitamin D

actin

Where are troponin, tropomyosin and nebulin located?

Which structure occurs at the border between two adjacent sarcomeres?

Z disc

The neurotransmitter released by the motor neuron to cause muscle contraction is

acetylcholine

The motor end plate differs from the rest of the sarcolemma in that it contains large numbers of ________.

acetylcholine receptors

Which of the following tissues could be found on or within a bone, such as the humerus? -adipose tissue -nervous tissue -cartilage -osseous tissue -all of these

all of these

By which process, as an individual grows to adulthood, is the thickness (diameter) of bone increased?

appositional growth

The ________is composed of hyaline cartilage and reduces friction between bones involved in a joint.

articular cartilage

Osteoblasts _____ bone tissues, while osteoclasts _____ bone tissues.

build up, break down

Which two minerals are stored in major quantities in bone tissue?

calcium and phosphorus

What are the extracellular fluid filled extensions of the lacunae called?

canaliculi

Osteons are found in _____, while trabeculae are found in _____.

compact, spongy

The zone of overlap increases during the

contraction period

During arm flexion, the type of contraction that would occur in triceps brachii is

eccentric isotonic contraction

The _______________ surrounds each individual muscle fiber and distributes capillaries to the fibers.

endomysium

The ________is composed of hyaline cartilage and allows the diaphysis to grow in length.

epiphyseal plate

Which region of a long bone articulates with other bones?

epiphysis

Which property of muscle gives it the ability to stretch without damage?

extensibility

Frequency of stimulation of a muscle cell is not a factor that influences tension.

false

What is yellow bone marrow?

fat

Which of the following is the correct sequence of steps in the repair of a bone fracture?

fracture hematoma, fibrocartilaginous callus formation, bony callus formation, bone remodeling

Once osteoblasts have surrounded themselves with the extracellular matrix of bone tissue, they remain inside little chambers called __________ where they carry on the metabolic functions that maintain bone tissue. At this point, the cells are called osteocytes.

lacunae

The hollow, cylindrical space within the diaphysis that contains fatty, yellow bone marrow in adults is called the

medullary cavity

During endochondral ossification in a fetus, bones initially develop as a cartilage model that was formed from

mesenchyme

In which region of a long bone, such as the humerus, would you find the epiphyseal plate (growth plate)?

metaphysis

What affects bone remodeling and growth?

minerals, vitamins, and hormones

Which term describes a somatic motor neuron and all the skeletal muscle fibers it stimulates?

motor unit

Even at rest, a skeletal muscle exhibits a small amount of tautness or tension in the muscle due to weak, involuntary contractions of its motor units which could be seen easily in a well trained athlete. What is this characteristic?

muscle tone

During the contraction cycle, ATP attaches to

myosin

During muscle relaxation, what does tropomyosin block?

myosin-binding sites on actin

Functions of calcium in the body

nerve cells require extracellular calcium ions (Ca2+) for proper functioning Ca2+ is a cofactor needed for many enzymes to function properly Ca2+ is required for the process of blood clotting Ca2+ is needed by muscle cells for contraction

The process of bone formation is referred to as ____.

ossification

Which is formed from the fusion of as many as 50 monocytes (a type of white blood cell)?

osteoclast

What is the correct sequence of development of bone cells?

osteoprogenitor cells → osteoblasts → osteocytes

A fasciculus is a subunit of a skeletal muscle surrounded by ________________.

perimysium

The muscle cell's contracting unit is known as the

sarcomere

In the muscle cell, calcium ions are stored in the

sarcoplasmic reticulum

Which type of muscle tissue is involuntary (can't be consciously controlled)?

smooth muscle and cardiac muscle

Which characteristics describe both skeletal and cardiac muscle?

striations

Skeletal muscle contraction is triggered to begin when calcium is released from

terminal cisterns of sarcoplasmic reticulum

The contractile organelle of skeletal muscle fibers is

the myofibril

Which protein does Calcium bind to?

troponin

Fused tetanus is caused by rapid muscle stimulations without muscle relaxation.

true

In a motor unit, all muscle cells move together from a single stimulation.

true

The opening of sodium channels is essential for the initiation of an action potential in the muscle cell membrane.

true

A brief contraction of all muscle fibers in a motor unit in response to a single action potential moving down the somatic motor neuron is known as

twitch contraction

myosin

what structure contains motor proteins that convert the energy in ATP into mechanical movements?