Bones (pt.1)
Give two functions of bones.
Support, Movement, and Protection
Metabolic Function [hematopoiesis & storage of minerals (calcium salts) and lipids]
What is the function of the periosteum vs. the function of the endosteum?
Periosteum - isolates and protects the bone
Endosteum - important for growth and remodeling
What is the difference between a closed and open fracture?
Closed: completely internal
Open: cuts through skin and projects out
Name the layers of skin from the most superficial (outside) to most internal.
Stratum Corneum
Stratum Lucidum
Stratum Granulosum
Stratum Spinosum
Stratum Basale
If someone is blushing vs if someone is pale, what is happening to the blood flow to the face in each case?
Redness/Blushing - increased blood flow to skin
Paleness - decreased blood flow to skin
What are the two solid parts of the extracellular matrix of bone tissue that give bone strength and resiliency?
Collagen Fibers (⅓) - tropocollagen
Hydroxyapatite Crystals (⅔)
[Water & Proteoglycans & Glycoproteins -- fluid portion of ECM not solid]
What are the two types of bone formation? Name two differences between the two?
Intramembranous Ossification - Skull and Clavicle ; Forms DIRECTLY form mesenchyme
Endochondral Ossification - Every Other Bone Except for Skull and Clavicle; Forms INDIRECTLY from mesenchyme
What is the function of Vitamin C in bones?
Normal collagen synthesis in osteoblasts
What are two methods of body temperature regulation by the skin?
Constriction/Dilation of Blood Flow to Skin
Activation of Sweat glands
What is the color of deoxygenated blood vs oxygenated blood?
Deoxygenated Blood- dark red/purple
Oxygenated Blood- bright red
Where is Red Bone Marrow found? Yellow Bone Marrow?
Red Bone Marrow - Interior of flat bones, epiphysis of long bones, and medullary cavity of children
Yellow Bone Marrow - found in the medullary cavity of long bones [except in children]
In both Intramembranous and Endochondral Ossification, bone matrix is initially laid down as ________ , by osteoblasts which is subsequently mineralized, and bone is produced first in disorganized fashion, known as _______.
Osteoid , Woven Bone
What is the difference between osteoporosis and osteopenia?
Osteoporosis = loss of bone mass and mineral content; brittle bones easily fractured
Osteopenia = decreased bone mineral density but not low enough to be considered osteoporosis
What is the active form of Vitamin D called, what is its function, and what’s a medical condition that can arise if its not present?
Calcitriol; Stimulation of absorption of calcium and phosphate from diet; Rickets
What are the 3 different types of secretion modes and how do they function?
Merocrine: Exocytosis, vesicles release contents at cell surface
Apocrine: Apical side or a portion of the cell will pinch off and burst and release contents
Holocrine: Whole cell bursts and releases content
Where in the bone does hematopoiesis occur? What about storage of lipids ?
Hematopoiesis - Red Bone Marrow
Lipid Storage - Yellow Bone Marrow
What occurs at the zone of calcification of the growth plate?
Death of Chondrocytes
Calcification of Matrix
After: Osteoblasts from diaphysis invade and turn calcification into bone
What are the names of the 4 phases of fracture repair?
Inflammation
Soft Callus Formation
Hard Callus Formation
Remodeling
What are the 5 cell types in the epidermis?
Keratinocytes
Merkel Cells
Melanocytes
Langerhans Cells
Stem Cells/Basal Cells
What are some differences between apocrine sweat glands and eccrine sweat glands?
Apocrine- Found in armpits, groin, around nipple; associated with scent; stimulation of secretion by emotional and sexual stimuli
Eccrine - Found throughout body, no scent (watery secretion); stimulation of secretion by thermoregulation and excretion
What are the 4 major bone types and their functions?
Osteoprogenitor Cells - Stem cells that differentiates into osteoblast
Osteoblast - immature bone cell that secretes organic components of bone matrix; [building of bone]
Osteocytes - Mature bone cell that maintains the bone matrix
Osteoclasts - Multinucleate cell that secretes acids and enzymes to dissolve bone matrix; [breakdown of bone]
Name the 5 stages of Endochondral Ossification and give a brief description of each.
Formation of Hyaline Cartilage: Mesenchyme turn into Chondroblasts/Chondrocytes which build Cartilage Model
Formation of Bony Collar: Blood Vessels grow around cartilage, and cells of Perichondrium turn into Osteoblasts to which build Bony Collar
Vascular Invasion: Blood Vessels, Osteoblasts and Osteoclasts invade center, Primary Ossification center forms, Osteoblasts replace cartilage with bone and spreads, Osteoclasts eat bone to make medullary cavity
Elongation: Blood Vessel invasion of epiphysis, formation of secondary ossification center, piece of cartilage left behind at epiphyseal plate to allow for elongation with growth
Epiphyseal Plate Ossification: After puberty growth plate becomes bone and is called the epiphyseal line
What are the functions of the following hormones: Parathyroid, Calcitonin, Thyroid, and Growth Hormone ?
Parathyroid: if not enough calcium in blood, will stimulate osteoclasts to breakdown bone
Calcitonin: if too much calcium in blood, will inhibit the osteoclasts preventing bone breakdown
Thyroid Hormone: stimulates cell metabolism and osteoblast activity
Growth Hormone: stimulates cell growth and division
What is the function of langerhans cells in the epidermis? What is the function of merkel cells? Where in the epidermis are the two cells located?
Langerhans Cells - immune response against microbes and cancer; stratum spinosum
Merkel Cells - mechanoreceptor that senses light touch/pressure; stratum basale
Name at least 3 mechanoreceptors, what they sense, and where they are located, if known, in the skin.
Merkel’s Discs - Fine touch and Pressure, Stratum Basale
Meissner’s Corpuscle - Fine Touch and Pressure on Glabrous Skin, Dermal Papillae
Ruffini Ending - Skin Distortion and Pressure, Deep Dermis
Pacinian Corpuscle - Deep Pressure/Vibration, Deep Dermis/Hypodermis
Nociceptors - Pain, Free Nerve Endings
Thermoreceptors - Temperature, Free Nerve Endings