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