Today: Hormones and the Endocrine System cont’d Hormones and the Endocrine System cont’d Case Study Case Study Into to Homeostasis? Into to Homeostasis?
Post on 28-Dec-2015
222 Views
Preview:
Transcript
Today:Today: Hormones and the Hormones and the
Endocrine System Endocrine System cont’dcont’d
Case StudyCase Study Into to Into to
Homeostasis?Homeostasis?Reminder: Next week’s
group quiz moved to Thursday!
Vertebrate Coordination of Vertebrate Coordination of Endocrine and Nervous Endocrine and Nervous
SystemsSystems Hypothalmus: Hypothalmus:
endocrine endocrine gland in the gland in the brain of brain of vertebratesvertebrates
Vertebrate Coordination of Vertebrate Coordination of Endocrine and Nervous Endocrine and Nervous
SystemsSystems Oxytocin: Oxytocin:
Positive-feedback Positive-feedback mechanism mechanism involved in involved in release of milk release of milk from mammary from mammary glands and glands and uterine uterine contractioncontraction
Vertebrate Vertebrate Coordination Coordination of Endocrine of Endocrine and Nervous and Nervous
Systems: Systems: ADHADH
What would an Anti-Diuretic
Hormone (ADH) do?
When would I produce it?
Vertebrate Vertebrate Coordination Coordination of Endocrine of Endocrine and Nervous and Nervous
Systems: Systems: ADHADH
Vertebrate Coordination of Vertebrate Coordination of Endocrine and Nervous Endocrine and Nervous
SystemsSystems Anterior pituitary Anterior pituitary
produces a variety of produces a variety of tropic and nontropic tropic and nontropic hormoneshormones
Tropic hormones Tropic hormones regulate the function of regulate the function of endocrine cells or glands. endocrine cells or glands. Example: Example: TSHTSH
Nontropic hormones Nontropic hormones target nonendocrine target nonendocrine tissues. Example: tissues. Example: MSHMSH
Vertebrate Coordination of Vertebrate Coordination of Endocrine and Nervous Endocrine and Nervous
SystemsSystems
Vertebrate Coordination of Vertebrate Coordination of Endocrine and Nervous Endocrine and Nervous
SystemsSystems A few hormones, A few hormones,
like Growth like Growth Hormone (GH) Hormone (GH) have both tropic have both tropic and nontropic and nontropic effectseffects
These impacts make GH tempting for adult athletes to abuse!
Rugby player makes history with Rugby player makes history with growth hormone bangrowth hormone ban
By ROBERT MILLWARD, AP Sports Writer Robert Millward, Ap Sports By ROBERT MILLWARD, AP Sports Writer Robert Millward, Ap Sports Writer Writer – Mon Feb 22, 2010 2:48 pm ET– Mon Feb 22, 2010 2:48 pm ET
LONDON – In a major breakthrough in the fight against doping, a British rugby league player has become the first athlete to be suspended for using human growth hormone.Terry Newton admitted taking the substance in a statement released by his attorneys on Friday. The United Kingdom Anti-Doping authority announced a two-year ban on Monday after Newton was fired by his club, Wakefield."It's the first time and very significant," WADA director general David Howman said. "It shows the people who say that HGH cannot be detected that it can. The sports people who said it can't be detected are fooling themselves."
Example: Example: TSHTSH, a tropic , a tropic
hormone, acts hormone, acts in a in a hormone hormone
cascadecascade
Functions of the Thyroid HormoneFunctions of the Thyroid Hormone
Involved in both homeostasis Involved in both homeostasis (blood pressure, heart rate, (blood pressure, heart rate, etc.) and developmentetc.) and development
Excessive secretion = Excessive secretion = hyperthyroidism (high temp, hyperthyroidism (high temp, high blood pressure, weight high blood pressure, weight loss)loss)
Insufficient production = Insufficient production = hypothyroidism (weight gain, hypothyroidism (weight gain, lethargy, intolerance to cold)lethargy, intolerance to cold)
Iodine was added to salt Iodine was added to salt in 1924 when up to a in 1924 when up to a third of US adults third of US adults suffered from goiter!suffered from goiter!
Next in Homeostasis Survey:Next in Homeostasis Survey:OSMOREGULATIONOSMOREGULATION
OsmoregulatioOsmoregulation:n:
management of management of body’s water body’s water and solute and solute
contentcontent
www.pbs.org
Transport EpitheliaTransport EpitheliaMost animals use layers of specialized Most animals use layers of specialized
epithelial cells to regulate solute epithelial cells to regulate solute movements. (Remember our tight movements. (Remember our tight
junctions??)junctions??)
Transport Transport EpitheliumEpithelium
Example: Salt Example: Salt excretion in excretion in marine birdsmarine birds
Osmoregulation: Metabolic Osmoregulation: Metabolic WastesWastes
Most wastes (except Most wastes (except COCO22) must be dissolved ) must be dissolved
in water to be in water to be eliminated, including eliminated, including nitrogenous wastes.nitrogenous wastes.
Breakdown of proteins Breakdown of proteins produces ammonia produces ammonia
(soluble but very toxic)(soluble but very toxic)
To secrete ammonia To secrete ammonia directly, must have directly, must have
access to lots of water!access to lots of water!
So what kinds of animals would you expect to secrete
ammonia directly?
Osmoregulation: Metabolic Osmoregulation: Metabolic WastesWastes
Osmoregulation: Metabolic Osmoregulation: Metabolic WastesWastes
Not an efficient strategy Not an efficient strategy for land animals!for land animals!Most mammals, Most mammals,
amphibians, marine amphibians, marine fish, turtles, etc., fish, turtles, etc.,
excrete mainly excrete mainly ureaurea
Urea is much less toxic, Urea is much less toxic, but but requires energyrequires energy
to produceto produce
Osmoregulation: Metabolic Osmoregulation: Metabolic WastesWastes
Option #3: Option #3: Uric AcidUric Acid
Land snails, insects, birds, Land snails, insects, birds, and some reptiles use and some reptiles use uric acid to eliminate uric acid to eliminate
nitrogenous wastenitrogenous waste
Uric Acid is also relatively Uric Acid is also relatively nontoxic, but insoluble nontoxic, but insoluble in water! (And even in water! (And even more expensive to more expensive to
produce!)produce!) So why bother??
Water BalanceWater Balance
All animals must balance the rate of All animals must balance the rate of water uptake and water losswater uptake and water loss
Two solutions: Two solutions: osmoconformersosmoconformers and and osmoregulators!osmoregulators!
Where do you expect to find each of these?
Measuring OsmolarityMeasuring Osmolarity
Osmolarity = total solute Osmolarity = total solute concentration expressed as moles of concentration expressed as moles of
solute per litersolute per liter
Common unit in biology = milliosmoles Common unit in biology = milliosmoles per liter (mosm/L)per liter (mosm/L)
Osmoregulation has Energetic Osmoregulation has Energetic CostsCosts
““Expense” depends on:Expense” depends on:
Concentration gradient between Concentration gradient between animal and environmentanimal and environment
Permeability of surface to water and Permeability of surface to water and solutessolutes
Energetic cost of membrane-Energetic cost of membrane-transport worktransport work
General Strategies: Saltwater General Strategies: Saltwater AnimalsAnimals
Invertebrates: Invertebrates: Most have Most have body fluids body fluids
that are that are isoosmotic to isoosmotic to
the the surrounding surrounding environmentenvironment
Nudibranch, Photo: Robbie Wong, MSU
Note: This is not as easy as it
seems!
General Strategies: Saltwater General Strategies: Saltwater AnimalsAnimals
Vertebrates: Most Vertebrates: Most have body fluids that have body fluids that
are hypoosmotic are hypoosmotic compared to the compared to the
surrounding surrounding environmentenvironment..
So which way does water
move?
HabitatOsm
(mOsm/litre)
Na K Ca Mg Cl Urea
Seawater 1000 459 10 10 53 538 -
Hagfish Seawater 1002 454 7 9 23 532 3
Lamprey Freshwater 248 120 3 2 2 96 0.4
Dogfish Seawater 1075 269 4 3 1 258 376
Stingray Freshwater 308 150 6 7 4 149 1
Flounder Sea water 337 180 4 3 1 160
Goldfish Freshwater 293 142 2 6 3 107Data courtesy of Professor Balment,
University of Manchester
Exceptions to the “Rule”: Exceptions to the “Rule”: Marine Sharks Marine Sharks
(Chondrichthyes)(Chondrichthyes) Internal salt Internal salt
concentration lowconcentration low Kidneys remove Kidneys remove
some of this salt; some of this salt; rest is excreted by rest is excreted by the rectal gland or the rectal gland or in fecesin feces
However, net However, net diffusion of water is diffusion of water is inward!!inward!!
Photo: Pisces Conservation LTD
General Strategies: Saltwater General Strategies: Saltwater AnimalsAnimals
Marine reptiles and Marine reptiles and birds drink seawater birds drink seawater to replace lost to replace lost water.water.
Kidneys cannot Kidneys cannot produce produce concentrated urine concentrated urine and excess salts are and excess salts are excreted using excreted using special glandsspecial glands..
Photo: BBC News
General Strategies: Freshwater General Strategies: Freshwater AnimalsAnimals
Net movement of water?
Salt issues?
General Strategies: Freshwater AnimalsGeneral Strategies: Freshwater Animals
Opposite problem! Opposite problem! Water is constantly Water is constantly diffusing in as salts are diffusing in as salts are lostlost
Many freshwater Many freshwater animals cope by animals cope by excreting large amounts excreting large amounts of very dilute urine, of very dilute urine, replacing salts through replacing salts through food and active food and active transport from the transport from the environmentenvironment
General Strategies: Freshwater AnimalsGeneral Strategies: Freshwater Animals
What about the What about the salmon??salmon??
Ocean-going salmon drink seawater and
excrete excess salt from the gills
After migrating to freshwater, they stop drinking and
produce lots of dilute urine
Also Problematic: Temporary Also Problematic: Temporary WatersWaters
Animals inhabiting Animals inhabiting temporary waters temporary waters
must have must have mechanisms for mechanisms for preventing the preventing the
effects of effects of desiccation desiccation
(anhydrobiosis)(anhydrobiosis) Ditylenchus larvae in anhydrobiosis(photo M.McClure)
General Strategies: Terrestrial General Strategies: Terrestrial AnimalsAnimals
Desiccation is a Desiccation is a serious serious regulatory regulatory challenge!challenge!
Many adaptations:Many adaptations: waxy coveringswaxy coverings nocturnal lifestylenocturnal lifestyle kidneys!kidneys!
A Kangaroo (desert) Rat
Example: This Kangaroo Rat doesn’t drink!
Potential sources of water??
ExcretionExcretion
Most systems share a Most systems share a two-step process:two-step process:
1. Fluid collection1. Fluid collection
2. Content adjusted 2. Content adjusted by selective by selective
reabsorption or reabsorption or secretionsecretion
ExcretionExcretion
Step 1: Fluid CollectionStep 1: Fluid Collection
Typically involves filtration Typically involves filtration through membranes of through membranes of
transport epitheliatransport epithelia
Membranes retain cells Membranes retain cells and large molecules and large molecules
(proteins); water and (proteins); water and small solutes end up in small solutes end up in
the filtratethe filtrate
This process is non-selective!
ExcretionExcretion
Step 2: Selective Step 2: Selective Reabsorption or Reabsorption or
SecretionSecretion
Useful solutes (glucose, Useful solutes (glucose, some salts, amino acids) some salts, amino acids)
are reabsorbed; are reabsorbed; nonessential solutes and nonessential solutes and
wastes are left or wastes are left or actively transported into actively transported into
the filtratethe filtrate
Animal Survey Stop 1: Animal Survey Stop 1: FlatwormsFlatworms
Planaria utilize simple Planaria utilize simple excretory systems excretory systems
called called protonephridiaprotonephridia
This system is a network This system is a network of dead-end tubules of dead-end tubules
branching through the branching through the body; cilia draw fluid in body; cilia draw fluid in through the flame bulb through the flame bulb into the tubule systeminto the tubule system
Animal Survey Stop 2: Animal Survey Stop 2: AnnelidsAnnelids
Most annelids utilize Most annelids utilize metanephridiummetanephridium
Each segment has a pair Each segment has a pair of metanephridia of metanephridia
immersed in coelomic immersed in coelomic fluid; fluid is collected in fluid; fluid is collected in
a ciliated funnel and a ciliated funnel and then passed through the then passed through the
collecting tubule and collecting tubule and out the nephridiopore out the nephridiopore
Photo: Dr. Frederic Janzen, ISU
Animal Survey Stop 3: Animal Survey Stop 3: InsectsInsects
Insects and terrestrial Insects and terrestrial arthropods utilize arthropods utilize
malpighian tubules malpighian tubules to to remove nitrogenous remove nitrogenous
wastes (and wastes (and osmoregulation)osmoregulation)
Outfoldings of the digestive Outfoldings of the digestive tract secrete wastes and tract secrete wastes and
salts from the hemolymph salts from the hemolymph into the lumen into the lumen
Survey Stop 4: Mammalian Survey Stop 4: Mammalian KidneysKidneys
Mammals have two Mammals have two kidneys, each supplied kidneys, each supplied
with LOTS of blood with LOTS of blood flow via the renal flow via the renal
artery; as a result, all artery; as a result, all blood is filtered blood is filtered
~every 30 minutes~every 30 minutes
Our kidneys can excrete Our kidneys can excrete urine 4X as urine 4X as
concentrated (1,200 concentrated (1,200 mosm/L) as our blood!mosm/L) as our blood!
Image: The Biology Project
Survey Stop 4: Mammalian Survey Stop 4: Mammalian KidneysKidneys
Functional Unit = the Functional Unit = the NephronNephron (single (single
long tubule with a long tubule with a ball of capillaries)ball of capillaries)
Kidneys are Kidneys are compacted bundles compacted bundles of nephrons (~1.3 of nephrons (~1.3
million) all draining, million) all draining, eventually, into the eventually, into the
ureterureterImage: The Biology Project
Kidney Kidney FunctioFunctio
nn1.Blood Pressure
forces fluid from the
blood (glomerulus)
into the lumen of
Bowman’s capsule
Non-selective!! (~180 L of
filtrate/day)
TEM of the TEM of the Proximal Proximal TubuleTubule
EM: Loyola University Chicago Stritch School of Medicine
Note all folding on the inner
surface of these cells.
Form and function!
Kidney Kidney FunctioFunctio
nn In the
descending loop,
membranes are highly
permeable to water. Water diffuses out passively!
(Note that this means the
interstitial fluid must be
increasingly concentrated!)
Kidney Kidney FunctioFunctio
nnIn the ascending
loop, the transport
epithelium is permeable to salt but not water. Salt
initially diffuses out, and is later
actively transported
out.
(Lots of energy expended here!)
Kidney Kidney FunctioFunctio
nn The collecting
duct actively reabsorbs
salt. This, in turn,
increases the rate of diffusion of water out of the filtrate.
top related