Bio K103 Chapter 48: Osmoregulation and Disposal of Metabolic Wastes

45-75%

fluid makes up how much of our body?

75%

skeletal muscle is about ___ water

20%

adipose tissue is about ___ water

dehydration

since skeletal muscle is mostly water, what must you be concerned about as you lose it?

intracellular fluid, interstitial fluid, blood plasma

list the body fluids from most to least prevalent in the body

interstitial (bulk) and blood plasma

what are the types of extracellular fluid?

blood plasma

what is interstitial fluid formed from?

water comes from interstitial fluid into bloodstream to dilute the salt

what happens when we eat something salty?

transports nutrients, gases, waste products, and other materials

what does blood plasma do?

form ions in solution, needed for neural conductance and muscle contraction

what do electrolytes do?

as ions move, water goes with them

how are osmosis and ion movement related?

osmotic pressure

the movement of water creates ___ ___

pressure exerted on hypertonic side of membrane to prevent net movement of water from hypotonic side

what is osmotic pressure?

maintain equal osmolarity

what is the goal of osmotic pressure?

number of osmoles of solute per liter of solution

what is osmolarity?

two osmoles

how many osmoles is one mole of NaCl?

active process of maintaining water and solute balance in the body to ensure homeostasis

what is osmoregulation?

osmotic pressure, water levels, solutes (ions, minerals, metabolites)

what does osmoregulation regulate?

glucose, vitamins, amino acids

what are metabolites?

excrete metabolic wastes (H2O, CO2, nitrogenous compounds)

what is the primary function of the excretory system?

metabolic regulation of pH, RBS production (erythropoietin), regulating blood pressure

what secondary processes is the excretory system involved in?

protein breakdown

nitrogenous wastes are a result of ___ ___

ammonic, urea, uric acid

what are the main nitrogenous waste products?

ammonia, urea, uric acid

list the 3 main nitrogenous bases from least to most complex

nearly all organisms

what animals produce ammonia?

low, easy to produce

describe the energy cost of ammonia

very high, need a lot of water

describe the water requirement for ammonia

very high, must be excreted quickly

describe the toxicity of ammonia

moderate, some ATP needed

describe the energy cost of urea

moderate (less than ammonia)

describe the water requirement for urea

low-moderate (safe for transport in blood)

describe the toxicity of urea

osmolyte to maintain cell volume

urea serves as an ...

all major animal groups

what animals produce urea?

very high

describe the energy cost of uric acid

very low

describe the water requirement for uric acid

reptiles, birds, insects, some species of arboreal frogs

what animals produce uric acid?

limited to no access to water, terrestrial dwellers and shelled embryos

describe that habitat of animals that produce uric acid

directly into water via gills or skin

how is ammonia excreted?

by kidneys into urine

how is urea excreted?

as a paste or solid (saves water)

how is uric acid excreted?

low

describe the toxicity of uric acid

organisms who are isosmotic with environment (salt water), don't actively regulate internal solute concentrations

what is an osmoconformer?

marine animals: mainly invertebrates, sharks, skates, and hagfish

what animals are osmoconformers?

organisms that maintain a constant internal environment by regulating water and ions, independent of environment

what is an osmoregulator?

vertebrates, marine invertebrates living in costal lagoons and estuaries

what animals are osmoregulators?

no

do invertebrates normally have multicellular excretory organs?

contractile vacuole pumps excess water out, important in freshwater

describe waste disposal in protists

renette glands (one or two) secrete waste through body wall or into digestive tract

describe waste disposal in nematodes

tuular excretory structures found in many invertebrates

what are nephridial organs?

osmoregulation and excretion

what are the roles of nephridial organs?

made up of simple or branching tubules, open to outside through nephridiopores

describe the structure of nephridial organs

protonephridia and metanephridia

what are the two types of nephridial organs?

acoelomates and coelomates (platyhelminthes and some annelids)

what animals have protonephridia?

interstitial flame cells on end of tubules, internal cilia propel interstitial fluid into tubules, closed on one end

describe the tubule structure in protonephridia

specialized cells with slit-like openings and cilia that beat to pull interstitial fluid into tubules

what are flame cells?

through slits in flame cells

what is the only way water can enter protonephridia?

cilia move filtrate through tubule, exits via nephridiopores

describe fluid flow in protonephridia

urine is often hypoosmotic, most nitrogenous waste leaves across body surface

describe waste removal in protonephridia

most annelids, mollusks, and crustaceans (coelomates)

what animals are metanephridia found in?

open at both ends, has a funnel cell structure

describe the tubule structure of metanephridia

open in interstitium (funnel) on end of tubule, cilia extend out from internal opening, other end opens externally through a nephridiopore

describe the funnel cell structure in metanephridia

fluid is drawn into tubule, solutes from coelom move into tubule and exit through nephridiopores

describe fluid movement in metanephridia

may be hypertonic (can be modified by surrounding capillaries)

describe urine in metanephridia

malpighian tubule system

what kind of excretory system do insects have?

embedded in interstitial space of insect's body cavity

where are malpighian tubules located?

blind ended, extend from gut wall

describe the structure of malpighian tubules

iso, hypo, or hypertonic (conserves water)

describe the urine produced by insects

ion (K+, Cl-) and uric acid movement into lumen, water movement into tubule, fluid modification along tubule, contents empty into gut

what is the function of malpighian tubules

kidney

in most vertebrates, the ___ is the main osmoregulatory and excretory organ

liver, digestive system, skin, cells, lungs

what structures (other than the kidney_ excrete waste products?

hypertonic

the body fluids of freshwater fishes are ___ to the environment

dilute urine, about 10% of nitrogenous waste

what do the kidneys excrete in freshwater fishes?

special gill cells actively transport salts from water into body

how does salt move in freshwater fishes?

through gills

how is most nitrogenous waste excreted in freshwater fishes?

no

do freshwater fishes drink water?

hypotonic

body fluids of saltwater fishes are ___ to the environment

produce very little amounts of concentrated urine (conserves water), have small or no glomeruli

describe the kidneys of saltwater fishes

excrete excess salts and ammonia

what do gills in saltwater fishes do?

yes

do saltwater fishes drink water?

accumulate urea, hypertonic to environment (facilitates water moving into body)

describe body fluids of cartilaginous fishes

large volumes of hypotonic urine

what do the kidneys in cartilaginous fishes produce?

not actively, drink some with eating

do cartilaginous fishes drink water?

salt glands: remove excess salt from blood without moving H2O out

what specialized structure do some saltwater drinking animals have and what does it do?

marine birds and sea turtles

what animals have salt glands?

highly concentrated

describe the urine of saltwater drinking animals

high-protein diet produces large amounts of urea, must be excreted in urine without losing too much H2O

how does the diet of saltwater drinking animals affect their waste products?

kidneys, urinary bladder, and associated ducts

what structures make up the human urinary system?

produced by kidneys, travels through ureter to bladder, carried out of body by urethra

what is the general urine pathway?

males are longer and part of the reproductive system, females are shorted and only a part of the urinary system

what are the differences between a male and female urethra?

yes

are the kidneys encapsulated?

retroperitoneal, behind peritoneal cavity alongside spine

describe the location of the kidneys

cortex, medulla

the outside portion of the kidney is the ___ while the inside is the ___

formation of concentrated urine, contain collecting ducts and loops of Henle

what is the role of the renal pyramids?

structures that collect urine from renal pyramids

what are minor calyces?

formed by minor calyces, funnel urine into renal pelvis

what are major calyces?

central collecting area before urine enters the ureter

what is the renal pelvis?

the functional unit of the kidney

what is the nephron?

renal corpuscle and renal tubule

what are the two main parts of the nephron?

renal capsule (Bowman's capsule), glomerulus, podocytes

what structures make up the renal corpuscle?

structure that surrounds the glomerulus and collects the filtrate

what is the renal capsule (Bowman's capsule)?