11 - Ion & Water Balance (4-22-19)

The correct answer consists of terms related to the biological processes that help organisms maintain stable internal conditions. The incorrect answers provided contain terms unrelated to the concept of maintaining internal balance in biological systems.

Various fish species exhibit different behaviors when it comes to transitioning between saltwater and freshwater environments, with some migrating between the two for different stages of their life cycle.

In marine environments, animals need to regulate their salt balance to prevent excess salt accumulation. In freshwater environments, animals need to prevent loss of salts and uptake of excess water. In terrestrial environments, animals need to conserve water due to the challenges of desiccation.

Water is essential for various biological functions in organisms, including being the primary component of cells, facilitating chemical reactions, and maintaining salt balance. Having the correct balance of water is crucial for the overall health and survival of organisms.

Tonicity refers to the relative concentration of solutes dissolved in a solution which can affect the movement of water into or out of cells, leading to changes in cell size and shape. Isotonic solutions maintain cell stability, hypertonic solutions cause cells to shrink, and hypotonic solutions cause cells to swell and potentially burst.

The correct answer includes various sources of water and solutes, such as water preformed in plant & animal tissue, metabolic water, and water generated as a result of oxidative phosphorylation. Groundwater, Rainwater, and Seawater are not explicitly mentioned as sources in the correct answer.

Homeostasis is the process by which animals maintain a stable internal environment by regulating various factors such as ion and water balance. It involves different combinations of tissues to achieve this balance.

Organisms can either be osmoconformers (having similar internal and external osmolarity) or osmoregulators (maintaining constant osmolarity regardless of external environment). Regarding ionic regulation, they can be ionoconformers (exerting little control over ion profile) or ionoregulators (controlling ion profile). Additionally, organisms can either be stenohaline (tolerating only a narrow range of external salinities) or euryhaline (tolerating a wide range).

Epithelial tissue serves as a protective barrier between the animal and its environment, both externally and internally, and aids in the absorption and transport of substances across various surfaces.

The integument is specifically defined as a tough outer protective layer in animals or plants.

Transport epithelia are specialized epithelial cells that facilitate the movement of solutes across membranes through selective transporters. These cells primarily utilize two main routes of transport: transcellular transport involves movement through the cell across membranes, while paracellular transport involves movement between cells.

The correct answer explains the reason why nitrogen excretion is necessary in animals due to the toxicity of ammonia produced during amino acid breakdown.

The correct roles of kidneys in maintaining homeostasis include maintaining blood volume, ion balance, and removing nitrogenous wastes from the blood, as well as playing various other roles such as regulating ion balance, blood pressure, pH balance, excretion of metabolic wastes & toxins, and hormone production.

The correct answer explains the main tasks of the kidney related to filtering impurities, metabolic wastes, and salt from the blood. It also includes additional details about the structure of the mammalian kidney and the process of urine excretion. The incorrect answers provided do not accurately reflect the primary functions of the kidney.

The nephron is the functional unit of the kidney responsible for filtering the blood and producing urine by removing waste and excess substances.

Urine production involves the processes of filtration to form filtrate, reabsorption of specific molecules, secretion of specific molecules, and finally excretion of urine from the body.

The tubule regions have distinct transport functions and permeabilities due to differences in epithelium. The loop of Henle is specifically permeable to water, not solutes. The distal tubule completes reabsorption for most solutes, not water.

Filtration is a process in the kidney where blood is filtered to remove waste products, excess ions, and water to form urine. The correct answer describes the specific steps of filtration in the nephron.

Reabsorption is a key process in the nephron where most water and salt are reabsorbed back into the blood to maintain homeostasis.

Secretion in renal physiology refers to the process of moving certain molecules from the blood into the filtrate, in contrast to reabsorption where molecules are moved from the filtrate back into the blood. This requires energy and transport proteins. Secreted molecules include K+, NH4+, H+, pharmaceuticals, and water-soluble vitamins.

The osmotic concentration of final urine is primarily determined by the permeability of the collecting duct to water, which is regulated by the hormone vasopressin. This control over water reabsorption influences whether urine is diluted or concentrated.

Hormones, dietary factors, vitamins, exercise, and emotional stress can all play a role in the regulation of urinary function. However, only hormones and specific dietary factors specifically mentioned in the correct answer directly influence kidney function and urine output.

Vasopressin/Antidiuretic Hormone (ADH) increases water reabsorption from the collecting duct by increasing the number of aquaporins. This process helps regulate the body's water balance.

Mineralcorticoids are responsible for controlling ion excretion, specifically acting on the kidneys to promote the reabsorption of sodium into the blood, which helps maintain normal blood pressure. This process involves stimulating sodium reabsorption from urine and enhancing potassium excretion.

Salt glands in reptiles and birds play a crucial role in osmoregulation by secreting a hyperosmotic fluid that aids in processing high levels of salt consumed during drinking and feeding.

Amphibians do not have a drinking mechanism like other animals; they absorb water through their skin.