Chapter 7 A&P

Growth in the length of a long bone occurs

at the epiphyseal plate

A ______________ fracture is one in which the bone is broken in mutlipe pieces usually due to a crushing injury.

comminuted

Spongy bone consists of interconnecting bony platelets called

trabeculae

The primary function of osteoclasts is to

break down bone

The flexible strength of bone occurs because of

collagen fibers

A fracture in the shaft of a bone is a break in the

diaphysis

If the secretion of parathyroid hormone (PTH) increase, osteoclast activity ___________, and blood calcium levels ____________.

increases, increases

Yellow bone marrow is

mostly adipose tissue

_______ are cells that secrete collagen and stimulate calcium phosphate deposition.

osteoblasts

Which cells have a ruffled border and secrete hydrochloric acid?

osteoclasts

The most common bone diseases is _________.

osteoporosis

Describe how blood calcium homeostasis is regulated. Be complete and include a full description of the cells and the hormones involved.

Blood calcium homeostasis regulates the correct amount of calcium levels the body needs to and from the bones. It involves two cells osteoblasts and osteoclasts and two hormones parathyroid hormone and calcitonin. Osteoblast produce bone from calcium in the blood. Osteoclasts breaks down bone . Calcitonin is produced by C cells from the thyroid gland when the blood calcium concentrations are too high by inhibiting osteoclasts or stimulating osteoblasts. Parathyroid hormone is secreted by the parathyroid gland when the blood calcium level is too low.

Describe three factors that effect bone growth and health.

Genetics - bone diseases may be hereditary and have mutated genes. Exercise - bone growth and maintenance can come from adding stress to tendons and ligaments. Nutrition - consuming vitamins like vitamin A, C, and D to strengthen bone.

Why is the maintenance of blood calcium homeostasis so important?

Low blood calcium (hypocalciumia) leads to Short stature, dry skin and hair, brittle nails, muscle cramps or spasms, tingling in the fingers and toes, Cataracts, weakened tooth enamel and seizures Excessive thirst and frequent urination due to kidneys working harder to filer the excess calcium in the blood. ricketts, osteomalacia High blood calcium (hypercalciumia) leads to upset stomach, nausea, vomiting and constipation; Bone pain, muscle weakness, lethargy, and fatigue; Confusion and depression caused by the interference with the way the brain works; Palpitations and fainting, indications of cardiac arrhythmia, and other heart problems due to the interference with the heart function. brittle bone disorder

Intramembranous ossification mainly produces bone of which shape?

flat

Calcium phosphate crystallizes in bone as a mineral called ______.

hydroxyapatite

Which of these is NOT a function of bone?

vitamin D storage