Anatomy and Physiology 1 Chapter 6 Bone Tissue

Where is hyaline cartilage located?

-Covers articular ends of long bones -Most of fetal skeleton -Most of larynx, trachea, nose

Parathyroid Hormone (PTH)

1) Indiscriminate osteoclast breakdown of bone to "mine" Ca2+ 2) Release of Calcitriol from kidneys to promote increased absorption of Ca2+

bone remolding

1) Infant-teenagers: Bone Growth/Deposit > Bone Resorption 2) Young adults-adults: Bone Growth/Deposit = Bone Resorption 3) Middle age adults - Senior Citizens: Bone Resorption > Bone Growth/Deposit

What are the general functions of bone?

1) Support 2) Protection 3) Anchorage 4) Mineral and Growth Factor Storage 5) Hematopoiesis 6) Triglyceride Storage 7) Hormone Production

Calcitriol

A hormone produced from vitamin D that acts in essentially the same manner as parathyroid hormone.

Osteon (Haversian System)

A unit of bone containing central canal and matrix rings

Lamellae

Concentric rings around the central canal, sites of lacunae

Central Canal (Haversian Canal)

Contains one or more blood vessels that carry blood to and from the osteon; run parallel to the surface of bone.

Testosterone (males) and Estrogen (females)

Eventually cause plate closure; Excess or deficit produces different outcomes

Canaliculi

Hairlike canals that connect lacunae to each other and the central canal

Compact Bone

Hard and dense, but not solid, bone tissue that is beneath the outer membrane of a bone.

Spongy Bone

Layer of bone tissue that has many small spaces and is found just inside the layer of compact bone.

Calcitonin

Lowers blood calcium levels

Bone Resorption (Bone Breakdown)

Maintained by osteoclasts, Accomplished by H+ from H2CO3 and lysosomal enzymes, Osteoclasts phagocytose demineralized matrix and dead osteocytes

Bone Deposits (Bone growth)

Osteoblasts produce matrix, 2 important factors: [Ca2+], [Pi], alkaline phosphatase, Calcium salts deposited throughout the matrix

Paget's disease

a bone disease of unknown cause characterized by the excessive breakdown of bone tissue, followed by abnormal bone formation

Osteoblasts

amateur cells that secrete osteoid (ground substance). Make new bone

Hypercalcemia

an abnormally high level of calcium in the blood

Hypocalcemia

an abnormally low level of calcium in the blood

What are the cells of cartilage?

chondrocytes

osteomalacia

disease marked by softening of the bone caused by calcium and vitamin D deficiency

Where is elastic cartilage located?

external ear, epiglottis

yellow bone marrow

gradually replaces red bone marrow in adult bones; functions as storage for fat tissue and is inactive in the formation of blood cells

What are the three types of cartilage?

hyaline, elastic, fibrocartilage

Where is fibrocartilage located?

intervertebral discs, pubic symphysis, discs of knee joint

Osteoclasts

large cells that resorb or break down bone; macrophages

What are the shape of bones?

long bones, short bones, flat bones, irregular bones

osteporosis

loss of bone density caused by excessive absorption of calcium from bone; bones become weak and break easily

Osteocytes

mature bone cells

What are the cells of the bone?

osteogenic cells, osteoblasts, osteocytes, osteoclasts, bone lining cells

rickets

osteomalacia in children; causes bone deformity

What are the membranes of cartilage?

perichondrium

What are the bone membranes?

periosteum and endosteum

endochondral ossification

process in which bone forms by replacing hyaline cartilage 1) Hyaline cartilage as a template upon which we make bone 2) Responsible for building all bones in body except for clavicles and cranial bones

Thyroid Gland

produces hormones that regulate metabolism, body heat, and bone growth

red bone marrow

produces red and white blood cells and platelets

Growth Hormone (GH)

regulates the growth of the body during infancy

Intremembranous Ossification

results in formation of cranial bones of the skull and the clavicles, flat bones mostly formed by this process 1) Occurs at cranial bones and clavicles 2) Makes bone from scratch instead of using a template

Volkmann's Canals (Perforating Canals)

run perpendicular to central canals, contain blood vessels and nerves that supply Haversian Canals

Parathyroid Glands

small pea-like organs that regulate calcium and phosphate balance in blood, bones, and other tissues

Lacunae

small spaces between the lamellae which contain osteocytes