Water Balance, Excretion, Nutrition, and Digestion Flashcards

Vocabulary flashcards covering core concepts of water balance, osmoregulation, nitrogenous waste excretion, essential nutrition, and digestive system adaptations.

Tonicity Scenarios Table

A summary table comparing solution types (isotonic, hypotonic, hypertonic), solute comparisons, water movement direction, and their specific effects on cells.

Osmotic Strategies Comparison Table

A reference table outlining the descriptions, examples, and evolutionary notes for osmoconformers and osmoregulators.

Nitrogenous Waste Forms Table

A comparative table detailing the toxicity, water requirements, production costs, and organism categories for ammonia, urea, uric acid, and guanine.

Water Balance & Excretion Quick Recap Table

A concise reference summarizing key concepts of osmosis, osmoregulation, nitrogenous wastes, excretory logic, nephron structures, and aquaporins.

Vitamin Storage Types Table

A summary table outlining fat-soluble vs water-soluble vitamins, their examples, and their storage characteristics in the body.

Autotrophs vs Heterotrophs Table

A comparative breakdown of definitions, examples, mechanisms, and notes for autotrophic and heterotrophic organisms.

Digestive System Regions Table

A table listing the regions of a complete digestive tract and their respective functions from mouth to large intestine.

Osmosis

The passive movement of water across a semi-permeable membrane from an area of high water concentration to an area of low water concentration, governed by solute levels.

Diffusion

The passive movement of solutes directly across a biological membrane from an area of higher concentration to lower concentration without energy consumption.

Facilitated Diffusion

The passive transport of solutes across a cell membrane down their concentration gradient using a channel or carrier protein without expenditure of energy.

Active Transport

The movement of solutes against their concentration gradient requiring cellular energy, frequently utilized to draw water osmotically along with the moved solutes.

Excretion

The physiological removal of metabolic waste products and unwanted substances, such as excess salts and urea, from an organism.

Secretion

The release of a synthesized substance from a cell or gland that performs a specific functional role after release, such as insulin or saliva.

Elimination (Egestion)

The discharge of undigested food matter from the alimentary canal, which is distinct from metabolic excretion.

Osmoconformer

An organism whose internal osmolarity matches its external environment in a 1:1 ratio, typical of marine invertebrates living in stable marine conditions.

Osmoregulator

An organism that actively maintains a constant internal osmolarity despite environmental changes, requiring energy and specialized physiological mechanisms.

Estivation

A state of dormancy undergone by organisms during dry or hot seasons to minimize metabolic rate and prevent water loss.

Ammonotelic

Describing organisms, such as aquatic invertebrates and most bony fish, that excrete nitrogenous waste primarily as highly toxic and soluble ammonia.

Ureotelic

Describing organisms, such as mammals, adult amphibians, sharks, and rays, that excrete nitrogenous waste primarily as urea.

Uricotelic

Describing organisms, such as birds, insects, and non-avian reptiles, that excrete nitrogenous waste primarily as low-toxicity uric acid.

Guanotelic

Describing organisms, such as spiders and scorpions, that excrete nitrogenous waste primarily as guanine crystals, requiring minimal to no water.

Protonephridia

The excretory network found in flatworms consisting of branched tubules and flame cells with beating cilia that drive fluid filtration.

Metanephridia

The excretory organ of annelids where fluid enters a ciliated nephrostome, moves through tubules for solute reabsorption, and exits via a nephridiopore.

Malpighian Tubules

Outfoldings of the insect gut that actively pump sodium, potassium, and uric acid into their lumen, drawing water osmotically to produce a dry nitrogenous waste paste.

Glomerulus

The capillary bed located in the renal cortex where non-selective pressure filtration of blood plasma occurs into the nephron.

Thick Ascending Limb

The segment of the loop of Henle that actively pumps out sodium and chloride into surrounding medullary tissue while remaining strictly impermeable to water.

Countercurrent Multiplier Concept

The nephron mechanism whereby active transport of salt in the thick ascending limb builds a hypertonic medullary gradient that draws water out of the descending limb and collecting duct.

Aquaporins

Specialized transmembrane channel proteins that facilitate water movement across cell membranes, particularly abundant in the renal collecting duct.

Guttation

The exudation of water droplets containing nitrogen from leaf tips due to elevated root pressure, typically occurring under excess nitrogen conditions.

Macronutrients

Essential chemical elements required by organisms in large amounts, specifically carbon, hydrogen, oxygen, nitrogen, phosphorus, and sulfur ($C$, $H$, $O$, $N$, $P$, $S$).

Micronutrients

Dietary components needed in small or trace amounts for vital physiological functions, comprising inorganic minerals and organic vitamins.

Essential Nutrients

Nutritional compounds that an organism cannot synthesize endogenously and must obtain directly through dietary intake.

Fat-Soluble Vitamins

Vitamins A, D, E, and K, which are absorbed alongside dietary lipids and stored short-term in adipose deposits.

Water-Soluble Vitamins

B-complex vitamins, folic acid, and vitamin C, which cannot be stored in body tissues and require regular dietary replenishment.

Hypervitaminosis A

A toxic pathological state resulting from excessive intake of vitamin A, leading to severe symptoms such as skin peeling, hair loss, seizures, and death.

Autotrophs

Organisms that synthesize complex organic molecules from abiotic inorganic sources such as carbon dioxide ($CO_2$).

Heterotrophs

Organisms that obtain organic nutrients by consuming or absorbing other living or dead organisms.

Chemosynthesis

A form of autotrophic nutrition where organic compounds are produced using energy derived from inorganic chemical reactions, such as oxidation of sulfur, rather than light.

Phototropism

The growth or turning movement of a plant toward a directional light source to maximize photon capture for photosynthesis.

Foregut Fermentation

Microbial breakdown of cellulose occurring in multi-chambered pre-gastric structures like the rumen before reaching the true stomach and small intestine.

Hindgut Fermentation

Microbial breakdown of cellulose taking place in enlarged post-gastric organs like the caecum after passing through the stomach.

Typhlosole

An internal longitudinal fold of the intestinal wall in earthworms that increases surface area for nutrient absorption.

Spiral Valve

A corkscrew-shaped structural modification inside the shark intestine that increases absorption surface area and retards transit time of food.