Ion and Water Balance 6: Other Animal Structures Flashcards
what structure do sponges use for water/ion balance
- simple contractile vacuoles
sponges: what are the functions of contractile vacuoles (2)
- expel cellular waste
- expel water
what structures do worm taxa have for water/ion balance
- protonephridia
worm taxa: protonephridia structure
- similar structure
- components (4)
- similar to vertebrate kidney tubule
- consists of: flame cell, flagella, lumen, and tubule cell
worm taxa: how do fluids travel through the protonephridia (2)
- fluids are taken from interstitial space into lumen by beating of flagella
- reabsorption occurs
worm taxa: which worm type have the most developed protonephridia structures (2)
- freshwater worm taxa
- they need to get rid of more water as water travels passively into the worm
what structure do molluscs and annelids use for water/ion balance
- metanephridia
molluscs/annelids: metanephridia structure (4)
- nephrostome
- lumen
- storage bladder
- nephridiopore
molluscs/annelids: how do fluids move through the metanephridia (2)
- fluid taken from blood or coelom into lumen
- some reabsorption takes place
what structure do insects use for ion/water balance
- Malpighian tubule
insects: Malpighian tubule structure
- general/location
- cell composition
- blind ending sac between the midgut and hindgut
- consists of Stellate cells and Principal cells
insects: Malpighian tubule Stellate cells (2)
- facilitate transport of Cl- from haemolymph into lumen
- facilitate transport of water into lumen through aquaporins
insects: Malpighian tubule Principal cells (2)
- facilitate K+ and other solute transport from haemolymph into lumen
- contain H+ ATPases into lumen
insects: Malpighian tubule movement of fluid (2)
- draws ions/water into lumen from the haemolymph
- “urine” is deposited into the hindgut
insects: how is the primary urine created in the Malpighian tubule (2)
- no ultrafiltrate is created (no filtration)
- primary urine is created solely by secretion
insects: what is secretion driven by in the Malpighian tubule and is it different than what vertebrates use (2)
- H+-ATPase
- different from vertebrates that normally use Na+/K+ ATPase
what are many insecticides based upon (2)
- how they affect Malpighian tubule
- how they affect hindgut function
insects: how is the primary urine further modified in the Malpighian tubule
- reabsorption and secretion in the hindgut
insects: how do diuretic hormones affect the Malpighian tubule
- increase urine formation
what are the components of the shark nephron (5)
- glomerulus
- ciliated neck
- proximal tubule
- distal tubule
- collecting tubule
what is the osmolarity of extracellular fluid in sharks compared to seawater
- EF is slightly hyperosmotic to seawater
sharks: why is the EF hyperosmotic to seawater
- high urea concentrations in the EF
sharks: how do they ensure high concentrations of urea in their EF (2)
- countercurrent arrangement in nephron recovers 90% of urea from primary urine
- uses Na+-urea transporter
what is the osmolarity of shark final urine compared to seawater
- final urine is isoosmotic to seawater
what is the osmolarity of shark final urine compared to its plasma
- final urine is slightly hypoosmotic to plasma
what distinguishes the nephrons of fish/sharks from terrestrial vertebrate nephrons
- all fish/shark nephrons lack a loop of Henle
do freshwater or marine fish have larger/more complex glomerula (2)
- freshwater fish have larger, more complex glomerula
- as freshwater fish are battling water influx, that must have a way to get rid of extra water
aglomular fish (2)
- describes nephrons that lack glomerulars in marine fish
- nephrons lack ability to create ultrafiltrate and must rely on secretion
what is the benefit of lacking a glomerular to create ultrafiltrate
- minimizes water loss
what is the downside of lacking glomerular to create ultrafiltrate
- can only secrete things that we have transporters for
freshwater fish: nephron components (6)
- glomerula
- ciliated neck
- proximal tubule
- inter-segmental region
- distal tubule
- collecting tubule
what are the roles of the kidneys in freshwater (3)
- ions reabsorbed from primary urine
- excretion of lots of very dilute urine
- most ion, water, and nitrogen excretion responsibilities met by skin and gills
what are the roles of the kidneys in seawater (3)
- produce small amounts of urine
- most ion, water, and nitrogen excretion responsibilities met by gills and skin
- some marine fish lack glomeruli (aglomerular kidney)
amphibian: nephron structure (6)
- glomerula
- ciliated neck
- proximal tubule
- inter-segmental region
- distal tubule
- collecting tubule
amphibian nephron: metamorphosis (2)
- structure and function of kidney will change as organism moves from water to terrestrial environment
- larval and adult forms
amphibian nephron: larval form (3)
- pronephros
- tubule opens into coelom
- similar to freshwater fish nephron, where lots of water needs to be secreted
amphibian nephron: adult form
- similar to mammal nephron
amphibian nephron: larval form function
- excretion of dilute urine as there is little need for water retention in dilute urine
amphibian nephron: adult form function (3)
- conserve water on land
- reduced the GFR
- reabsorb water from bladder
reptile nephron: structure (5)
- glomerula
- proximal tubule
- inter-segmental region
- distal tubule
- collecting tubule
why is the loop of Henle considered a ‘major innovation’ in terrestrial animals
- allows production of concentrated urine for water conservation
where organisms have loop of Henles in their nephrons (2)
- birds
- mammals
what are characteristics of mammals producing more concentrated urine (2)
- longer loop of Henle
- relatively thicker medulla
how do birds and reptiles without the loop of Henle conserve water (2)
- excrete uric acid instead of urea
- lots of water is saved in production
