Anatomy Exam 3

Who am I? I am composed of tubular units called osteons. I am adapted to support weight and withstand torsion stress. I also provide attachment site for muscle.

compact bone

Which of the following best describes lacunae within compact bone?

hole in the matrix that holds an osteocyte

The depolarization of the membrane reaches the sarcoplasmic reticulum via

t-tubule, and sarcomere

What is the term for the structure at C?

A-band

In which stage of ossification does the primary marrow cavity appear?

B

Where would red bone marrow be found in this adult femur?

B

If this were the femur of a ten-year-old child, where would red marrow be found?

B and C

What is stored within the organelle at C (sarcoplasmic reticulum)?

Calcium ions

In which stage of ossification is an epiphysial plate present?

D

T or F: Bones, cartilage, and ligaments are tissues and organs of the skeletal system.

True

T or F: A radiograph (X-ray) of a child's hand will show epiphysial lines.

False

T or F: Concentric lamellae within an osteon are connected by lacunae.

False

T or F: Osteogenic cells are bone stem cells that differentiate into osteoblasts and osteoclasts.

False

What tissue is the callus at B largely formed from?

Fibrocartilage

T or F: Parathyroid hormone (PTH) binds to receptors on osteoblasts.

True

Which of the following best describes the central canal of the osteon?

Hole in the matrix that holds blood vessels and nerves

Which of the following is an inorganic component of the bone matrix?

Hydroxyapatite

What is the key ion for establishing the resting membrane potential?

Potassium

Which of the following best describes the concentric lamellae of compact theme?

Rings of bone tissue

During the period of relaxation, what is happening in the muscle fiber on a molecular level?

calcium is being taken up by the sarcoplasmic reticulum

the electrical signal from a neuron is carried to a muscle by the neurotransmitter called

acetylcholine

Contraction of a sarcomere occurs because of sliding __________ past __________

actin / myosin

Between what two structures does a cross-bridge form?

actin and the myosin heads (B and C)

If a thyroid tumor secreted an excessive amount of calcitonin, we would expect ___________.

an elevated level of osteoblast activity

In appositional bone growth, new bone is deposited around a __________.

blood vessel

Which of the forms of prenatal bone development applies to the following: primary ossification center

endochondral

Which of the forms of prenatal bone development applies to the following: creation of osteoid followed by calcification of the matrix via calcium salts

endochondral and intramembranous

Which of the forms of prenatal bone development applies to the following: uses cartilage as a blueprint

endochondral and intramembranous

Appositional bone growth is a process that __________.

forms new bone on the surface of older bone

What is the blood clot at A called?

hematoma

What tissue does stage A primarily consist of?

hyaline cartilage

The hardness of bone comes from __________, whereas __________ provide(s) some degree of flexibility.

hydroxyapatite and other minerals; proteins

How do you think milk affects bone density?

increase bone density

How do you think weight-bearing activities affects bone density?

increase bone density

Which of the forms of prenatal bone development applies to the following: creates the bones of the skull

intramembranous

Wolff's law of bone explains the effect of __________.

mechanical stress on bone remodeling

Which of the following muscle structures is the largest?

myofibril

Which structure binds ATP during contraction?

myosin (B)

The intracellular side of the membrane for most cells carries a _________ charge

negative

Which cell is responsible for bone deposition?

osteoblast (B)

Which cell is stimulated by the hormones calcitriol and PTH?

osteoblast (B)

New bone is deposited by cells known as __________.

osteoblasts

Who am I? I produce new bone tissue by secreting bone matrix

osteoblasts

Who am I? I am multinucleated. I have a ruffled border and break down bone by secreting enzymes that dissolve the matrix.

osteoclast

Who am I? I am the organic part of the bone matrix that gives it tensile strength.

osteoid

Blood Ca2+ deficiency stimulates __________ secretion, which leads to __________.

parathyroid hormone; increased osteoclast activity

A long bone is covered externally with a sheath called the __________, whereas the marrow cavity is lined with the __________.

periosteum; endosteum

Which of the following muscle structures is the smallest? muscle tissue, myofibril, sarcomere, or muscle fiber

sarcomere

Patches of fibrocartilage formed in the healing of a fracture are called __________, whereas the bony collar formed around the fracture is called __________.

soft callus; hard callus

Who am I? I am highly porous and contain red bone marrow. I am also rich in blood vessels. I form the diploe of flat bones.

spongy bone

Which of the following best describes the canaliculi of osteons?

thin tubes in the matrix that allow movement of materials in the matrix

Before a cross bridge can occur, calcium ions must bind to:

troponin

Where do calcium ions bind during a muscle contraction?

troponin (D)