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Physiology - Block 1 - Part 2

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davidwurbel7's version from 2015-06-06 22:37

Muscle Physiology

Question Answer
Consist of a large molecular weight protein called myosinThick Filaments
Has 1 pair of heavy chains which coil around each other to formMyosin Tail
Light chains along with terminal portions of the heavy chains formMyosin Head
Has TWO important features - ability to hydrolyze ATP (ATPase activity) and has high affinity for binding with actin (when ATP is split into ADP & Pi)Myosin Head
Composed of 3 proteins; F-Actin, Tropomyosin & TroponinThin Filament
There are 2 strands of Actin moleculesF-Actin
Has binding site for MyosinF-Actin
At rest, Myosin -binding sites are covered byTropomyosin
A calcium binding protein complex consisting of 3 globular proteinsTroponin
Binds Ca2+ producing conformational change which moves Tropomyosin away, exposing Myosin-binding sites on ActinTroponin C
Attaches Troponin complex to TropomyosinTroponin T
Inhibits actin- myosin interaction along with Tropomyosin by covering the Myosin-binding sites on Actin, at restTroponin I
The basic contractile unit of the muscleSarcomere
Extends from one Z-line to another. Contains one full A- band & two half I-bandsSacromere
In the centre containing thick (Myosin) filaments. Therefore appear dark. Thick & thin filaments may overlap at this region during cross bridge formationA Band
Located on either sides of A band. They contain thin filaments. Mainly Actin, also Troponin & Tropomyosin and therefore appear lightI Band
Darkly staining structures running in middle of each I bandZ Disk
Located in centre of each Sarcomere. It has no thin filaments & there is no overlap of thick & thin filaments at this zoneH Band
Present in bare zone connects central portions of thick filaments togetherM Line
Normal, fully stretched resting length is about 2 - 2.2 micrometersSarcomere
Invaginations of muscle cell (Sarcolemmal) membrane which carry depolarization during Action potentials from muscle cell surface to the interiorTransverse (T) tubules
Contains voltage-sensitive protein called Dihydropyridine receptorTransverse (T) tubules
Transverse (T) tubules contain this voltage-sensitive receptorDihydropyridine Receptor
Site of storage & release of Ca2+ for Excitation-contraction couplingSarcoplasmic Reticulum (SR)
Contains a Ca2+- releasing channel called as Ryanodine receptorSarcoplasmic Reticulum (SR)
Sarcoplasmic reticulum contains a Ca2+- releasing channel calledRyanodine receptor
Pumps Ca2+ from ICF of muscle fiber into SRCa2+ - ATPase
Within SR, Ca2+ is bound to a Ca2+ binding protein calledCalsequestrin
The sequence of events which translate muscle action potential into muscle contractionExcitation - Contraction Coupling (EC Coupling)
Occurs when Ca2+ returns to its storage site in SR by Ca2+ - ATPase, decreasing intracellular Ca2+ levelsRelaxation
An increase in the amount of Ca+2 in the ICF will increase the number ofCross Bridge Cycling
Force of contraction of the muscle without a change in the length of muscle. Force of contraction is equal to the load against which it contracts. Hence no work is doneIsometric Contraction
Force of Contraction against a constant load, in which length of muscle decreases. Here, force of contraction of the muscle is greater than the load against which it contracts. Hence work is doneIsotonic Contraction
Repeated action potentials on a muscle cause sustained contraction of the muscleTetanus
The organism responsible for causing tetanusClostridium tetani
This toxin blocks release of inhibitory neurotransmitter GABA & GlycineTetanospasmin
Treatment includes antitoxin administration which neutralizes the circulating toxin; Any wound should be explored & cleaned properly; Antitoxin injection should be taken immediately following an injury and antibioticsTetanus
Metornidazole and Penicillin-G are the antibiotics used againstTetanus
Force generated in muscle when it is stretched (without contraction) by a load at restPassive Tension
Force generated in muscle when it actually contracts (sliding of myofilaments)Active Tension
Active tension is maximal when there is a maximal overlap of thick & thin filaments & maximum number of cross bridges.Optimal Length
Muscle being stretched (without contraction) by a load at restPreload
The force against which the muscle contractsAfterload
The amount of Ca+2 available for a contractionContractility
The amount of Ca+2 released by the SR and the preload determines theForce of Contraction
Type of muscle at optimal length at resting conditionsSkeletal Muscle
Type of muscle at optimal length when stretched; Preload moves sarcomere closer to optimal length increasing the force of contraction with more stretchCardiac Muscle
The speed of myosin ATPase activity, the afterload on muscle and motor unit recruitment contribute toVelocity of Contraction
Type of muscle that are large, powerful muscle utilized for a short term; High ATPase activity (fast muscle); Larger number of muscle fibers in each motor unit; High capacity for anaerobic glycolysis; Low MyoglobinWhite (Fast Twitch) Muscle
Type of muscle that are small, less powerful muscle utilized long term (endurance muscle); Lower ATPase activity (slow muscle); Smaller number of muscle fibers in each motor unit; High capacity for aerobic metabolism; Red color due to high MyoglobinRed (Slow Twitch) Muscle
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Endocrinolgy

Question Answer
Collection of axons within the nervous systemTract
Collection of neural cell bodies located togetherNucleus
Sex hormones, Adrenocortical hormones, Active Vitamin D (1,25 DHCC)Steroid Hormones
Anterior and posterior pituitary hormones, Hypothalamic hormones, Parathyroid hormones, Calcitonin, Insulin, GlucagonProtein and Polypeptide Hormones
Catecholamines - Epinephrine, Norepinephrine, Triodothyronine(T3), Thyroxine(T4)Amine Hormones
The receptor of this hormone is located on the external surface of the cell membraneWater Soluble Hormones
The receptor of this hormone is located inside the nucleus of the cell or in the cytoplasmLipid Soluble Hormones
The solubility of Triodothyronine(T3), Thyroxine(T4) and all steroid hormonesLipid Soluble Hormones
The solubility of Epinephrine, Norepinephrine and protein and polypeptide hormonesWater Soluble Hormones
These hormones are synthesized when required and are not stored, half life is longer (in hours/days) and is proportional to their affinity for protein carrier. The exception is T3/T4Lipid Soluble Hormones
These hormones are stored in vesicles, have shorter half life and half life is proportional to their molecular weightWater Soluble Hormones
The secondary messenger for CRH; ACTH, TSH; FSH, LH; MSH; ADH; Calcitonin, PTH; Catecholamines (most actions), HCG, Glucagon; Vasopressin via V2 receptorscAMP
The secondary messenger for ANP, Nitric Oxide (Endothelium Derived Relaxing Factor (EDRF))cGMP
The secondary messenger for TRH, GnRH, Vasopressin via V1 receptors (smooth muscle cell in blood vessel), GHRH, Oxytocin, Catecholamine (some actions)Calcium\Phosphatidyl Inositol Triphosphate (IP3)
The secondary messenger for GH, Prolactin, and InsulinTyrosine Kinase/ Phosphatase
An increase in concentration of a particular hormone or their effect directly/indirectly inhibits further secretion of that hormoneNegative Feedback Mechanism
A hormone has biologic actions that directly/indirectly causes more secretion of that hormonePositive Feedback Mechanism
Down regualation of _________ in the uterus, down regulates its own receptors and receptors for EstrogenProgesterone
GnRH, GH, ACTH, Cortisol are secreted in a pulsatile manner which preventsDown Regulation
Chronic high circulating levels of a hormone can decrease the number of its receptors on the target cell. This is calledTissue Resistance
The hormone that causes release of more binding proteins by the liverEstrogen
Liver dysfunction and these types of hormones decrease circulating levels of binding proteinsAndrogens
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Hypothalamus

Question Answer
CRH is produced in this part of the hypothalamusPara Ventricular Nucleus (PVN)
TRH is produced in this part of the hypothalamusPara Ventricular Nucleus (PVN)
GnRH is produced in this part of the hypothalamusPreoptic Nucleus (PO)
GHRH is produced in this part of the hypothalamusArcuate Nucleus (AN)
Somatostatin is produced in this part of the hypothalamusPara Ventricular Nucleus (PVN)
PRIH is produced in this part of the hypothalamusArcuate Nucleus (AN)
Hypothamlamic hormone CRH produced in the paraventricular nucleus (PVN) targets which pituitary hormoneACTH
Hypothamlamic hormone TRH produced in the paraventricular nucleus (PVN) targets which pituitary hormoneTSH
Hypothamlamic hormone GnRH produced in the preoptic nucleus (PO) targets which pituitary hormoneLH and FSH
Hypothamlamic hormone GHRH produced in the arcuate nucleus (AN) targets which pituitary hormoneGH
Hypothamlamic hormone Somatostatin produced in the paraventricular nucleus (PVN) inhibits which pituitary hormoneGH
Hypothamlamic hormone PRIH produced in the arcuate nucleus (AN) inhibits which pituitary hormoneProlactin
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Hormone Disorders

Question Answer
If defect is in the target gland from which hormone has originatedPrimary Disease
If defect is in the Anterior PituitarySecondary Disease
If defect is in HypothalamusTertiary Disease
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