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75 Cards in this Set

  • Front
  • Back
functions of bone
Ca+2 Homeostasis
Blood Cell Production
Energy Storage
two basic bone types
Compact (dense) bone
Spongy (cancellous) bone
small needle-like pieces of bone that makes up spongy bone
trabeculae. Trabeculae align themselves along lines of stress like little struts. they have a large amount of open space filled with yellow or red bone marrow
both compact and spongy bone are composed of:
B.Extracellular Matrix
Extracellus Matrix of bone contains:
1.Collagen Fibers
2.Ground Substance (Osteoid)
a. Water
b. Organic material (glycoproteins, proteoglycans)
c. Inorganic salts calcium + phosphate = hydroxyapatite)
Cells found mainly in the periosteum & endosteum
osteogenic cells
derived from osteogenic cells
-Known as bone-forming cells
-Synthesis & secrete unmineralized osteoid and collagen
-Pump calcium & phosphate salts into and out of bone tissue
derived from osteoblasts

-Derived from osteoblasts that have secreted osteoid around themselves
-Osteoid becomes calcified
-Referred to as mature bone cells
derived from monocytes

Known as bone-resorbing (dissolving) cells
mature bone cells
thought of as tiny, weight-bearing pillars
Osteons (Haversian Systems)
Concentric rings of compact bone tissue that help form the osteons
contain the "ingredients"
Bony depression in the lamellae in which bone cells are housed
Canals found in the core of osteons in which blood vessels and nerves pass through
Haversian (Cental) Canals
Canals that connect osteons together; also a passageway for blood vessels and nerves to enter and leave bone
Volkmann’s (Perforating) Canals
__________ form tall columns like coins in a stack
_________ at the top of the epiphyseal plate divide quickly – this increases the thickness of the epiphyseal plate and pushes the diaphysis away from the epiphysis
During infancy and childhood, bone growth is stimulated by:
-Growth hormone
-Thyroid hormone
During adolescence, bone growth is stimulated by
-Growth hormone
-Testosterone & estrogen
_________ and ________ are needed in adult life for normal bone maintenance.
Testosterone and estrogen
At the end of puberty, testosterone and estrogen induce _________________ or fusion, resulting in the epiphyseal line and thereby ending longitudinal bone growth.
epiphyseal plate closure
bone ends are coaxed back into their normal position by hand
closed reduction
surgery is performed and the bone ends are secured together with pins or wires
open reduction
Bone contributes to homeostasis of the human body in 2 primary ways:
-Bone marrow helps maintain the concentration of blood cells in the vasculature
-Bone helps maintain calcium levels in the ECF
Bone is able to contribute to Ca+2 homeostasis under the direction of the endocrine system – what two hormones play key roles?
parathyroid hormone (PTH) & calcitonin (CT).
PTH increases serum calcium by 3 mechanisms:
1)stimulation of bone resorption, with release of calcium and phosphate into the circulation
2)increased production of 1,25-(OH)2 vitamin D (calcitriol), which increases intestinal absorption of calcium
3)increased reabsorption of filtered calcium by the renal tubules to prevent loss of Ca in urine
(2 effects on kidney and 1 on bone)
Skin is able to make vit D with help of sunlight. Sunlight converts provit D (______) into Vit D3 (______) and Vit D3 is absorbed and enters blood and goes to liver (still _______) and then to kidneys where it is __________ (last step). PTH stimulates the enzyme in the kidney that _____ Vit D.
inactive, inactive, inactive, activated, activates
________ is a protein hormone (32-amino acids) that is synthesized and secreted by the parafollicular cells of the thyroid gland.
stimulated by hypercalcemia
inhibits osteoclast activity and stimulates osteoblasts to pump in more calcium into the bone tissue.
________ occurs in children, __________ in adults. Bones are inadequately mineralized, so they become soft and weak
Weight-bearing bones bend and deform.
rickets, osteomalacia
In smooth muscle,Ca attaches to:
what are the three types of smooth muscle?
1)Multi-Unit Smooth Muscle
is present is iris, vas deferens, arrector pili
behaves as separate motor units
2)Single-Unit Smooth Muscle
is present in uterus, GI tract, urinary bladder
has pacemaker activity & cooridinated contractions
3)Vascular Smooth Muscle
has properties of both multi-unit & single-unit
is present in uterus, GI tract, urinary bladder
has pacemaker activity & cooridinated contractions
single-unit smooth muscle
what is the organization level of skeletal muscle?
myofilaments > myofibril > muscle cell (muscle fiber) > fascicle > muscle
Excitation-Contraction Coupling

Neurotransmitter is released and diffuses across synaptic cleft and attaches to Ach receptors in _______.
1)Action potential generated is propagated along _____ and down _______.
sarcolema, T tubules
2)Action potential triggers _____ release from terminal ______ of _____________ ___________
Ca2+, terminal cisternae, sarcoplasmic reticulum
3)Calcium ions bind to ______; ______ changes shape, removing the blocking action of _________; actin active sites exposed
troponin, troponin, tropomyosin
4)Contraction; myosin cross bridges alternately attach to actin and detach, pulling the actin filaments toward the center of the ______; release of energy by _____ hydrolysis powers the cycling process
sarcomere, ATP
5)Removal of _____ by active transport into the _____ ______ after the action potential ends
Ca2+, sarcoplasmic reticulum
6)_________ blockage of restored blocking actin active site; contraction ends and the muscle fiber relaxes
•primary function is to produce & secrete hormones
list of classical endocrine glands:
•pituitary gland
•thyroid gland
•parathyroid glands
•adrenal glands
•gonads testes and ovaries
•primary function is not endocrine related
•gastrointestinal tract
Hormones exert their functions in four broad physiological areas:
1•maintenance of homeostasis (e.g. -- blood glucose, blood pressure, plasma osmolality, RBC count, etc.)
2•helping the body cope with "stressful" events
3•regulation of cellular metabolism and energy balance
4•regulation of growth, development and reproduction
hormones that act on neighboring cells
paracrine function
hormones that act upon themselves:
autocrine function
episodic release of about an hour
episodic release approximately every 24 hrs
episodic activity is expressed at defined periods of the day
episodic release approximately every month (30 days)
episodic release longer than an hour but less than 24 hrs
Three major classes of hormones:
1-Steroid Hormones
2-Protein / Peptide Hormones
3-Biogenic Amines
what hormones are lipids that are derived from cholesterol and synthesized in smooth endoplasmic reticulum
these hormones differ because of their "side chains
these hormones are lipophilic and hydrophobic
• Majority these hormones are carried in the blood via "shuttle buses" or transport (plasma) proteins
what is used to transport steroid hormones
transport proteins - albumin, globulins
these hormones are 3-30 amino acids in length -- TRH being the smallest at 3 amino acids (glutamate - histidine - proline)
these hormones are 30-225 amino acids in length -- LH being one of the largest at 204 amino acids
Chemically are lipophobic and hydrophilic
where are protein/peptide hormones synthesized?
Synthesized on ribosomes, RER and Golgi complex (preprohormone to prohormone to active hormone); the peptide "scraps" that are left over as a preprohormone is cleaved to form the active hormone are often stored and co-secreted along with the active hormone
biogenic amine hormones are derived from what amino acid
________ hormones are examples of biogenic amines that are chemically similar to steroid hormones (i.e. - lipophilic & hydrophobic)
examples of biogenic amines that are chemically similar to protein hormones (i.e. - lipophobic & hydrophilic)
catecholamines; epinephrine and norepinephrine
Hormones circulate either _____ or _____ to
plasma proteins.
free, bound
In most cases the free hormone:
-is the fraction available for binding to receptors and therefore represents the active hormone
-dictates the magnitude of feedback inhibition that controls hormone release
is the fraction that is cleared from the circulation
-correlates best with clinical states or hormone excess and deficiency
A synthetic drug that mimics the action of antidiuretic hormone and is used for diabetes insipidus
Desmopressin (synthetic ADH) can be given intranasally or subcutaneously (although oral form does exist now)
Binding of steroid and thyroid hormones to plasma proteins greatly _____ their clearance from the plasma. Hence, they can remain in the blood for several hours or even days. Many of the protein/peptide hormones and catecholamines are _________ and circulate freely in the blood. As a result, they can be degraded much more quickly and often have half-lives of only several minutes.
slows, water soluble
Protein hormones and catecholamines will bind to receptors embedded in the plasma membrane. Once they bind to their receptors, protein hormones then work through _______________such as cAMP
This leads to the _________ of cytosolic proteins, which in turn, triggers a physiological response by the target tissue.
2nd messenger systems, phosphorylation

This is a way for hormones to signal the TT to do something indirectly.
Steroid and thyroid hormones bind to intracellular receptors, which can be located either in the cytoplasm or in the nucleus. This binding activates what is termed the ______________.
direct gene mechanism
____________ or an increase in the number of available receptors, also occurs and can be seen in some target tissues in an effort to increase sensitivity to a hormone
up regulation
this affects sensitivity: cell can decide how much response it wants from a hormone
up or down regulation
_______________ interact with the DNA binding domain of steroid hormone receptors, thereby preventing the receptor from binding to the HREs on DNA, halting transcription & decreasing the cell’s response to the hormone.
Heat shock proteins
Drugs that bind to receptors and elicit the same or even a more potent biological response as the naturally occurring hormone.
hormone receptor agonist
Molecules that bind to receptors but fail to elicit the normal biological response are termed _______________________ as they occupy the receptors and prevent the binding of the naturally occurring hormone.
competitive antagonists (or just antagonists)