Question 1: Homeostasis
Homeostasis is a self-regulating process that seeks to maintain the stability of biological processes while at the same time adjusting to conditions optimal for survival (Delp and Laughlin, 412). The balance attained is not constant, but a dynamic equilibrium characterized by continuous changes seeking to maintain relatively uniform conditions. The initial increment in blood flow to exercising skeletal muscles is an autoregulatory process. The decline in tissue oxygen leads to the cellular liberation of chemicals that dilate the local vasculature. Autoregulated vascular bed dilatation leads to increases in the rate of blood flow and thus increased oxygen supply to the regions before endocrine and nervous responses; it is independent of nervous or endocrine response (412).

You're lucky! Use promo "samples20"
and get a custom paper on
"Anatomy and Physiology"
with 20% discount!
Order Now

The control of mechanisms of the local vasculature in autoregulatory responses to skeletal muscle exercise includes endothelium mediated control, muscle pump response, metabolic control, myogenic control, and propagation responses (Delp and Laughlin, 413). A muscle’s metabolic rate primarily determines its perfusion during exercise. The direct diffusion of metabolites liberated from the exercising muscles into resistance arterioles acts directly as vasodilators and as indirect inhibitors of the release noradrenaline from nerve endings thus opposing vasoconstriction mediated by adrenoreceptors. Mediator substances released from the vascular endothelium such as nitric oxide and prostacyclin prominently function to establish the basal vascular tone (415).

The central control mechanisms consisting both neural and hormonal systems are also responsible for the regulation of cardiac activity and the tone of regional and whole body vasculature, in turn, maintaining the homeostasis of systemic vasculature over exercise. Hormonal factors exert their influence on skeletal muscle vascular bed resistance as a cardiovascular reflex and orthostatic response, but from research, it does not appear to be of primary importance in exercise-induced hyperemia phenomena (Thomas and Segal, 733).

The sympathetic nervous system mediates neuronal control of vasculature resistance through the coordination of these alternations by directing increases sympathetic outflows to the heart, which increases cardiac output and evokes baroreflex-mediated vasoconstriction in ‘non-vital’ peripheral organs such as the GIT, the kidneys, and the non-exercising muscles. Their blood is redistributed to the contracting skeletal muscles and to maintain blood pressures (Thomas and Segal, 734). Vasoconstriction mediated by sympathetic adrenergic mediators contributes to the milieu mediating the net decrement in the resistance of blood vessels in the exercising skeletal muscle; however, it is not the cause of exercise hyperemia.

Question 4: The Consequences of Cilia Destruction
Playing a critical role in the defenses of respiratory systems are the complexly minute but powerful cellular structures termed Cilia (Dustin 87). Epithelium in the respiratory tract is extensively lined by cilia which perform an integral role in a coordinated manner, termed mucociliary clearance. Through mucociliary clearance, cilia transport the mucus blanket that overlies the respiratory mucosa for ingestion in the GI tract; primarily clearing debris, allergens, pathogens, and toxins from the airway.

The ciliated epithelium moves mucus back toward the throat, where it is eventually swallowed or expelled coughing. Mucus traps foreign particulates, such as dust or microorganisms, which in the absence of cilia would build up within the paranasal sinuses. Possible consequences may include congestion, pain, sinusitis, anosmia, and spread of infections into the respiratory tract (Helms 922).

Question 5: Blood Tests Ordered to Determine the Occurrence of Muscle Damage
Creatine Phosphokinase Test (CK test, CPK or Creatine Kinase)
The CK enzyme converts muscle creatine into phosphate, used as a quick source of energy in muscle cells. The damage of muscle cells liberates CK into the bloodstream; a rise in the blood levels of CK are indicative of muscle injury (Jacoby and Youngson 1292). Care should be taken to differentiate between the subtypes of CPK indicative of heart and brain damage. CPK tests may also be used in the evaluation of suspected myositis in the absence of symptoms, inform on a suspected neuromuscular disorder, or check for disease progression after treatment. CPK tests are repeatedly taken to obtain more accurate results. CK levels in an adult vary depending on race, ethnicity, gender, testing method, health status, and physical activity. Higher serum CK levels and indicative of muscle damage from a chronic disease or acute muscular injury. In myositis, it is not uncommon for CK levels to far exceed the upper limit of normal. Importantly, CK levels are not directly related to feeling better or worse; the levels tend to lag behind disease improvement or worsening.

The Aldolase Test
Aldolase enzyme is abundantly found in muscles. Damage to muscle cells results in the liberation of this enzyme. The amount of aldolase measured in blood is directly related to the extent of muscle damage. However, as muscle damage worsens over time, the amount of aldolase measured in blood also reduces with time. Proper aldolase tests are taken after 8 hours of non-eating leading to the test. The normal aldolase ranges are dependent on the method used in their measurement.

The Erythrocyte Sedimentation Rate (ESR, or Sed Rate)
The ESR is indicative of muscular inflammation (not specific to muscle inflammation); it is used in monitoring the progress of inflammation. The average ESR rates for males range between 0-15mm/hr, while for females the rangers are 0-20mm/hr (Marshall Cavendish Reference Books 211). ESR rates are higher in pronounced inflammation; they may also be elevated in elderly persons and pregnant women.

Other Blood Tests
Jacoby and Youngson (1292) indicate that other blood tests that may be ordered are levels of Aspartate aminotransferase (AST) and Alanine aminotransferase (ALT). These enzymes are not specific to muscle cells as they are present in other tissues such as the liver; they are however useful in indicating the presence of muscle damage. Their normal value ranges are dependent on age, gender, liver function and other factors. The Factor VIII (von Willebrand)-related antigen serum levels are used to indicate damages to the blood vessels smooth muscles more so in juvenile myositis (JM). Lactate dehydrogenase is also another enzyme present in muscle tissue. Its normal value ranges typically are between 105-333 IU/L (international units per liter) (Marshall Cavendish Reference Books 211). The enzyme is useful in indicating muscle damage.