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27 Cards in this Set
- Front
- Back
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What is homeostasis?
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it is the relative constancy of the internal environment
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In order to maintain internal constancy the vertebrate body uses a type of control system called?
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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 |
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What are some examples of the sensors, integrating centers and effectors?
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sensors = baroreceptors or chemoreceptors
integrating center = cardiovascular control center effectors = nervous system |
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What is osmolality?
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moles of solute / kilogram of H2O is
total solute concentration of an organism determines osmotic behavior |
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What is osmoptic pressure?
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is the measure of a solutions tendency to take in water
hypertonic - shrink hypotonic - swell isotonic - remain constant |
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What are osmoconfromers?
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extracellular fluid or ECF is same as surroundings
example: many marine inverts take on the osmolality of seawater |
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What is an osmoregulator?
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all other verts that maintain a constant blood osmolality despite their environment
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What osmolality is freshwater?
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hypotonic
into cell = swells |
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What is the osmolality of saltwater?
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hypertonic
flows out = shrink |
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Why are osmoregulatory tubules used in some animals?
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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 |
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Name some osmoregulatory organs belonging to inverts?
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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 |
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What is the function of nephrons in the kidney?
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they allow the filtration of blood from the glomerulus (a filter) to bowman's capsule
reabsorption = urine to blood secretion = blood to urine |
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In order to avoid osmotic problems freshwater fish must?
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excrete lots of water because freshwater = hypotonic
don't drink much pump in solutes across gills and reabsorption of solutes in nephron tubes |
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What must marine fish do in order to avoid osmotic problems?
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drink lots of water
not excrete a lot of water actively remove salts via gills |
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How are cartilaginous fish different from bony fish?
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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 |
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What is different about the vertebrate kidney of mammals and birds?
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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 |
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How do mammals and birds produce highly concentrated urine?
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through loops of henle
portion of nephron = hypertonic environment draws out a lot of water to produce more concentrated urine |
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What is nitrogenous waste?
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ammonia
produced from excess amino acids and nucleic acids very TOXIC! |
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How do didfferent types of animals eliminate N waste?
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fish secrete ammonia directly
amphibians and mammals eliminate urea reptiles, birds and insects eliminate uric acid |
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How is urine produce in the mammilian kidney?
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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 |
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What do nephrons do for the kidney?
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it allows reabsorption, filtration and secretion
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Explain the process of urine production in the mammilian kidney?
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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 |
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What are the proximal convluted tubules within the mammilian kidney?
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it is the site of bulk reabsorption of salt and water
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What drives the reabsorption of salt and water within the proximal convoluted tubules?
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the active transport of na molecules = water reabsorption
electrical grad = cl- reabs co transport = glucose and amino acids |
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If ADH or antidiruetic hormone were not present in the distal convoluted tubule what would this do to the urine concentration and its volume?
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ADH allows water to be permeable and exit the tubule
urine would be very diluted because the water would be left in the tubule |
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When is thne ADH released by the DCT?
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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 |
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What hormones control electrolyte balance?
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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 |
