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)