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27 Cards in this Set

  • Front
  • Back
What is homeostasis?
it is the relative constancy of the internal environment
In order to maintain internal constancy the vertebrate body uses a type of control system called?
a negative feeback loop

-sensors constantly measure conditions
-relay information to the integrating center that know proper condition
-integrating center sends a message to effectors (muscles or glands) to change
What are some examples of the sensors, integrating centers and effectors?
sensors = baroreceptors or chemoreceptors
integrating center = cardiovascular control center
effectors = nervous system
What is osmolality?
moles of solute / kilogram of H2O is

total solute concentration of an organism determines osmotic behavior
What is osmoptic pressure?
is the measure of a solutions tendency to take in water
hypertonic - shrink
hypotonic - swell
isotonic - remain constant
What are osmoconfromers?
extracellular fluid or ECF is same as surroundings

example: many marine inverts take on the osmolality of seawater
What is an osmoregulator?
all other verts that maintain a constant blood osmolality despite their environment
What osmolality is freshwater?

into cell = swells
What is the osmolality of saltwater?

flows out = shrink
Why are osmoregulatory tubules used in some animals?
excretory system expels waste AND water and salts go with it
tubules allow waste to exit AND allow water and salts to be reabsorbed into the body

tubules only opened to the outside of body allowing only the waste to go through
Name some osmoregulatory organs belonging to inverts?
earthworm = nephridia tubule allows close relationship between the excretory system and the blood

insects = malpighian tubes secrete K+ into tubules by active transport creating an osmotic gradient that pulls water into the tubules and allows the body to reabsorb it

vertebrates = kidneys create a fluid (urine)by filtration of the blood under pressure
What is the function of nephrons in the kidney?
they allow the filtration of blood from the glomerulus (a filter) to bowman's capsule

reabsorption = urine to blood
secretion = blood to urine
In order to avoid osmotic problems freshwater fish must?
excrete lots of water because freshwater = hypotonic

don't drink much

pump in solutes across gills and reabsorption of solutes in nephron tubes
What must marine fish do in order to avoid osmotic problems?
drink lots of water

not excrete a lot of water

actively remove salts via gills
How are cartilaginous fish different from bony fish?
they adapt to their salty surrounding = maintain a high blood urea concentratic = ISOTONIC

they survive in their surrounding without having to retain or excrete a lot of water, keeping the salts in their body constant
What is different about the vertebrate kidney of mammals and birds?
only vertebrates with highly concentrated urine

allows them to secrete their waste products in a small volume of water so that more water can be reatined for the body
How do mammals and birds produce highly concentrated urine?
through loops of henle

portion of nephron = hypertonic environment draws out a lot of water to produce more concentrated urine
What is nitrogenous waste?

produced from excess amino acids and nucleic acids

very TOXIC!
How do didfferent types of animals eliminate N waste?
fish secrete ammonia directly

amphibians and mammals eliminate urea

reptiles, birds and insects eliminate uric acid
How is urine produce in the mammilian kidney?
klidneys receive blood from the renal artery and produces urine

once the urine is produced the ureter drains the urine and carries it to the urinary bladder

kidney is divided up into renal cortex = outer
renal medulla = inner
What do nephrons do for the kidney?
it allows reabsorption, filtration and secretion
Explain the process of urine production in the mammilian kidney?
blood enters the kidney through the renal artery

it is filtered by glomerular cappilary walls

small solutes and water are allowed to penetrate the nephron tubules for either reabsortion or secretion

glomerular filtrate enters bowman capsule and moves to proximal convoluted tube

moves towards medulla into the loops of henle

filtrate moves to distal convolutes tubes and drains into the collectiong duct to renal pelvis
What are the proximal convluted tubules within the mammilian kidney?
it is the site of bulk reabsorption of salt and water
What drives the reabsorption of salt and water within the proximal convoluted tubules?
the active transport of na molecules = water reabsorption

electrical grad = cl- reabs

co transport = glucose and amino acids
If ADH or antidiruetic hormone were not present in the distal convoluted tubule what would this do to the urine concentration and its volume?
ADH allows water to be permeable and exit the tubule

urine would be very diluted because the water would be left in the tubule
When is thne ADH released by the DCT?
it is released when plasma osmolality is increase

in other words when the organism needs to conserve water or is dehydrated or eats salty food
What hormones control electrolyte balance?
aldosterone = stiumulated by decreased blood pressure and elevated levels of K+

promtoe the reabsoption of NaCl and water across the DCT and the secretion of K+ into the tubule

atrial natriuretic hormone = decrease NaCl reabsorption