To identify the process by which body systems are kept within certain limits. To explain the role of feedback mechanisms in homeostasis. To distinguish negative feedback from positive feedback.
By the end of this section, you will be able to: Describe the role of the kidneys in vitamin D activation Describe the role of the kidneys in regulating erythropoiesis Provide specific examples to demonstrate how the urinary system responds to maintain homeostasis in the body Explain how the urinary system relates to other body systems in maintaining homeostasis Predict factors or situations affecting the urinary system that could disrupt homeostasis Predict the types of problems that would occur in the body if the urinary system could not maintain homeostasis All systems of the body are interrelated.
A change in one system may affect all other systems in the body, with mild to devastating effects. A failure of urinary continence can be embarrassing and inconvenient, but is not life threatening. The loss of other urinary functions may prove fatal.
A failure to synthesize vitamin D is one such example. Vitamin D Synthesis In order for vitamin D to become active, it must undergo a hydroxylation reaction in the kidney, that is, an —OH group must be added to calcidiol to make calcitriol 1,dihydroxycholecalciferol.
Calcium is vitally important in bone health, muscle contraction, hormone secretion, and neurotransmitter release. Deficits may also result in problems with cell proliferation, neuromuscular function, blood clotting, and the inflammatory response. Recent research has confirmed that vitamin D receptors are present in most, if not all, cells of the body, reflecting the systemic importance of vitamin D.
Many scientists have suggested it be referred to as a hormone rather than a vitamin. Erythropoiesis Erythropoetin EPO is a hormone produced by the kidney that stimulates the formation of red blood cells in the bone marrow.
The kidney produces 85 percent of circulating EPO; the liver, the remainder. If you move to a higher altitude, the partial pressure of oxygen is lower, meaning there is less pressure to push oxygen across the alveolar membrane and into the red blood cell.
One way the body compensates is to manufacture more red blood cells by increasing EPO production. If you start an aerobic exercise program, your tissues will need more oxygen to cope, and the kidney will respond with more EPO.
If erythrocytes are lost due to severe or prolonged bleeding, or under produced due to disease or severe malnutrition, the kidneys come to the rescue by producing more EPO. Renal failure loss of EPO production is associated with anemia, which makes it difficult for the body to cope with increased oxygen demands or to supply oxygen adequately even under normal conditions.
Anemia diminishes performance and can be life threatening. ADH stimulation of aquaporin channels allows for regulation of water recovery in the collecting ducts. Normally, all of the glucose is recovered, but loss of glucose control diabetes mellitus may result in an osmotic diuresis severe enough to produce severe dehydration and death.
A loss of renal function means a loss of effective vascular volume control, leading to hypotension low blood pressure or hypertension high blood pressurewhich can lead to stroke, heart attack, and aneurysm formation.
The kidneys cooperate with the lungs, liver, and adrenal cortex through the renin—angiotensin—aldosterone system see Chapter 25 Figure 4. The liver synthesizes and secretes the inactive precursor angiotensinogen.
When the blood pressure is low, the kidney synthesizes and releases renin. Renin converts angiotensinogen into angiotensin I, and ACE produced in the lung converts angiotensin I into biologically active angiotensin II Figure 1.
The immediate and short-term effect of angiotensin II is to raise blood pressure by causing widespread vasoconstriction. Regulation of Osmolarity Blood pressure and osmolarity are regulated in a similar fashion.
Severe hypo-osmolarity can cause problems like lysis rupture of blood cells or widespread edema, which is due to a solute imbalance. Inadequate solute concentration such as protein in the plasma results in water moving toward an area of greater solute concentration, in this case, the interstitial space and cell cytoplasm.
If the kidney glomeruli are damaged by an autoimmune illness, large quantities of protein may be lost in the urine. The resultant drop in serum osmolarity leads to widespread edema that, if severe, may lead to damaging or fatal brain swelling. Severe hypertonic conditions may arise with severe dehydration from lack of water intake, severe vomiting, or uncontrolled diarrhea.
When the kidney is unable to recover sufficient water from the forming urine, the consequences may be severe lethargy, confusion, muscle cramps, and finally, death. Recovery of Electrolytes Sodium, calcium, and potassium must be closely regulated.
This loss of conformation may be a consequence of the breaking of hydrogen bonds. Move the pH away from the optimum for a specific enzyme and you may severely hamper its function throughout the body, including hormone binding, central nervous system signaling, or myocardial contraction.
Proper kidney function is essential for pH homeostasis.The urinary system influences homeostasis by regulating the amount (volume) and the makeup (composition) of blood. The makeup of blood is regulated in a couple ways.
In addition to maintaining fluid homeostasis in the body, the urinary system controls red blood cell production by secreting the hormone [glossary term:] erythropoietin.
The urinary system also plays a role in maintaining normal blood pressure by secreting the enzyme renin. The urinary system is also directly involved in maintaining proper blood volume (and indirectly blood pressure) and ion concentration within the blood.
The ureters, urinary bladder, and urethra together form the urinary tract, which acts as a plumbing system to drain urine from the kidneys, store it, and then release it during urination. Besides filtering and eliminating wastes from the body, the urinary system also maintains the homeostasis of water, ions, pH, blood pressure, calcium Continue. The urinary system sustains homeostasis by eliminating wastes from the body, regulating blood acidity levels and controlling the levels of metabolites and electrolytes in the blood, such as sodium, potassium and calcium. The urinary system also maintains a stable internal environment by assisting. The urinary system contains the kidneys, which are considered to be the organs of homeostasis mostly because they control the electrolyte balance in the blood, water retension in the body, and that they also play a role in maintaining blood pressure.
One other contribution is that the kidneys produce a hormone (erythropoietin) that stimulates red blood cell production. Start studying THE URINARY SYSTEM.
Learn vocabulary, terms, and more with flashcards, games, and other study tools. The urinary system is also directly involved in maintaining proper blood volume.
The kidneys also play an important role in maintaining the correct salt and water content of the body. External changes, such as a warm weather, that lead to excess fluid loss trigger feedback mechanisms that act to maintain the body’s fluid content by inhibiting.
The urinary system is also directly involved in maintaining proper blood volume. The kidneys also play an important role in maintaining the correct salt and water content of the body.
External changes, such as a warm weather, that lead to excess fluid loss trigger feedback mechanisms that act to maintain the body’s fluid content by inhibiting.