AP Bio Excretory System (KFogler)

2006-2007 AP Biology

Regulating the InternalEnvironment

2006-2007 AP Biology

Credit: created by

Kim Fogler

Division Avenue High SchoolLevittown

AP Biology

Conformers vs. Regulators 2 methods for organisms

regulate internal environment maintain relatively constant internal conditions

conform to external environment allow internal conditions to fluctuate along with external changes

conformer

thermoregulation

regulator

conformer

osmoregulation

regulator

AP Biology

Homeostasis Keeping the balance

animal body needs to coordinate many systems all at once temperature blood sugar levels energy production water balance & intracellular waste disposal nutrients ion balance cell growth

maintaining a “steady state” condition

2006-2007 AP Biology

Regulating the InternalEnvironmentWater Balance &

Nitrogenous Waste Removal

AP Biology

intracellular waste

extracellular waste

Animal systems designed to support multicellular life

O2

CHO

CHO

aa

aa

CH

CO2

NH3aa

O2

CH

O2

aa

CO2

CO2

CO2

CO2

CO2

CO2 CO2

CO2

CO2

CO2

NH3

NH3 NH3

NH3

NH3

NH3

NH3NH3

O2

aa

CH

aa

CHO

O2

Diffusion too slow!

AP Biology

Solving exchange problem Multicellular systems for

distributing nutrients circulatory system

removing wastes excretory system

overcoming the limitations of diffusion

overcoming the limitations of diffusion

aa

CO2

CO2

CO2

CO2

CO2

CO2 CO2

CO2

CO2

CO2

NH3

NH3 NH3

NH3

NH3

NH3

NH3NH3

O2

aa

CH

aa

CHO

O2

AP Biology

Osmoregulation

Why do all land animals have to conserve water?

always lose water (breathing & waste) may lose life while searching for water

Water balance freshwater

hypotonic water flow into cells & salt loss

saltwater hypertonic water loss from cells

land dry environment need to conserve water may need to conserve salt

AP Biology

Waste disposal What waste products?

what do we digest our food into… carbohydrates = CHO lipids = CHO proteins = CHON nucleic acids = CHOPN

relatively small amount in cell

CO2 + H2O

NH2 =

ammonia

CO2 + H2O CO2 + H2O

CO2 + H2O + N

CO2 + H2O + P + N

|

| ||H

HN C–OH

O

R

H–C–

Animalspoison themselves

from the insideby digesting

proteins!

cellular digestion…cellular waste

AP Biology

Nitrogenous waste disposal Ammonia (NH3)

very toxic carcinogenic

very soluble easily crosses membranes

must dilute it & get rid of it… fast!

How you get rid of nitrogenous wastes depends on who you are where you live (habitat)

AP Biology

AP Biology

Aquatic organismscan afford to

lose water ammonia

most toxic

Terrestrialneed to

conserve waterurea

less toxic

Terrestrial egglayersneed to conserve

most wateruric acid

least toxic

Nitrogen waste

AP Biology

Freshwater animals Water removal & nitrogen waste disposal

surplus of water can dilute ammonia & excrete it

need to excrete a lot of water anyway so excrete very dilute urine

pass ammonia continuously through gills or through any moist membrane

loss of salts reabsorb in kidneys or active transport across gills

AP Biology

Land animals Nitrogen waste disposal on land

have less toxic waste product need to conserve water urea = less soluble = less toxic

kidney filter wastes out of blood reabsorb H2O

excrete waste urine = urea, salts, excess sugar & H2O

urine is very concentrated concentrated NH3 would be too toxic

AP Biology

Urea Larger molecule = less soluble

2NH2 + CO2 = urea combined in liver

Requires energy to produce worth the investment

of energy

Filtered out by kidneys collected from cells

by circulatory system

H

HN

H

HN

C O

AP Biology

Egg-laying land animals Nitrogen waste disposal in egg

no place to get rid of waste in egg need even less soluble molecule

uric acid = bigger = less soluble = less toxic birds, reptiles, insects

itty bittyliving space!

AP Biology

N

N N

N

O

HO

O

H

HH

Uric acid Polymerized urea

large molecule precipitates out of solution

doesn’t harm embryo in eggwhite dust in egg

adults excrete white pasteno liquid wastewhite bird “poop”!

And that folks,is why a male bird

doesn’t have a penis!

AP Biology

Mammalian System Key functions

filtration fluids from blood collected includes water & solutes

reabsorption selectively reabsorb needed

substances back to blood secretion

pump out unwanted substances to urine

excretion remove excess substances & toxins

from body

blood filtrate

urine

AP Biology

Organs of the Urinary systemOrgans of the Urinary system

Kidneys

Ureters

Urinary bladder

Urethra

AP Biology

Location of the KidneysLocation of the Kidneys

Against dorsal wall

Right lower than left

Attached to ureters, renal blood vessels, & nerves at renal hilus

Atop kidney is adrenal gland

AP Biology

Regions of the KidneyRegions of the Kidney

Renal cortex – outer region

Renal medulla – inside the cortex

Renal pelvis – inner collecting tube

AP Biology

Mammalian Kidney

kidney

bladder

ureter

urethra

inferiorvena cava

renal vein& artery

nephron

epithelialcells

aortaadrenal gland

AP Biology

Nephron Functional and structural units

of kidney1 million nephrons

per kidney Function

filter out urea & solutes (salt, sugar…) : form urine

Processblood plasma filtered

into nephronselective reabsorption of

valuable solutes & H2O greater flexibility & control

“counter current exchange system”

AP Biology

The Kidney

Proximaltubule

Distal tubule

Glomerulus

Collecting ductLoop of Henle

Aminoacids

Glucose

H2O

H2O

H2O

H2O

H2O

H2O

Na+ Cl-

Mg++ Ca++

Interaction of circulatory & excretory systems

Circulatory system glomerulus =

ball of capillaries Excretory system

nephron Bowman’s capsule loop of Henle

descending limb ascending limb

collecting duct

How candifferent sectionsallow the diffusion

of different molecules?

Bowman’s capsule

Na+ Cl-

AP Biology

Nephron: Filtration At glomerulus

filtered out of blood H2O

glucose salts / ions urea

not filtered out cells proteins

high blood pressure in kidneys force to push H2O & solutes out of blood vessel

high blood pressure in kidneys force to push H2O & solutes out of blood vessel

BIG problems when you start out with high blood pressure in systemhypertension = kidney damage

BIG problems when you start out with high blood pressure in systemhypertension = kidney damage

AP Biology

Nephron: Re-absorption

Descendinglimb

Ascendinglimb

Proximal tubule reabsorbed

NaCl active transport Na+

Cl- follows by diffusion

H2O glucose HCO3

-

bicarbonate buffer for

blood pH

AP Biology

Descendinglimb

Ascendinglimb

Nephron: Re-absorption Loop of Henle

descending limb high permeability to

H2O

many aquaporins in cell membranes

low permeability to salt

reabsorbed H2O

structure fitsfunction!

AP Biology

Nephron: Re-absorption

Descendinglimb

Ascendinglimb

Loop of Henleascending limb

low permeability to H2O

Cl- pump Na+ follows by

diffusion different membrane

proteins

reabsorbed salts

maintains osmotic gradient

structure fitsfunction!

AP Biology

Nephron: Re-absorption Distal tubule

reabsorbed salts H2O

HCO3-

bicarbonate

AP Biology

Nephron: Reabsorption & Excretion Collecting duct

reabsorbed H2O

excretion urea passes to

bladderDescending

limbAscending

limb

AP Biology

Osmotic Control of nephron How is all this re-absorption achieved?

tight osmotic control to reduce the energy cost of excretion

use diffusion instead of active transportwherever possible

the value of acounter current exchange system

AP Biology

AP Biology

Summary Not filtered out

remain in blood (too big) cells proteins

Reabsorbed: active transport Na+ amino acids Cl- glucose

Reabsorbed: diffusion Na+ Cl-

H2O Excreted

urea (highly concentrated) excess H2O excess solutes (glucose, salts) toxins, drugs, “unknowns”

2006-2007 AP Biology

Any Questions?

2006-2007 AP Biology

Regulating the InternalEnvironment

Regulation of Homeostasis

AP Biology

Sensorconstantlymonitors

conditions

Negativefeedback loop

completed

ResponseReturn toset point

Stimulusdeviation from

set point

Perturbingfactor

Effectorcauses changesto compensatefor deviation

Integratingcentercomparesconditions toset point

Negative Feedback Loop Maintaining homeostasis

AP Biology

sensor

Negative Feedback Model

high

low

hormone 1

lowersbody condition(return to set point)

hormone 2

gland

raisesbody condition (return to set point)

gland

sensor

specific body condition

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Controlling Body Temperature

high

low

nerve signals

sweat

nerve signals

brain

body temperature

shiver brain

dilates surfaceblood vessels

constricts surfaceblood vessels

Nervous System Control

AP Biology

nephron

low

Blood Osmolarity

blood osmolarityblood pressure

ADH

increasedwater

reabsorption

increasethirst

high

Endocrine System Control

pituitary

AP Biology

H2O

H2O

H2O

Maintaining Water BalanceGet morewater intoblood fast

Alcohol suppresses ADH…

makes youurinate a lot!

High blood osmolarity level too many solutes in blood

dehydration, high salt diet stimulates thirst = drink more release ADH from pituitary gland

anti-diuretic hormone increases permeability of collecting duct

& reabsorption of water in kidneys increase water absorption back into blood decrease urination

AP Biology

nephron

low

Blood Osmolarity

blood osmolarityblood pressure

ADH

increasedwater

reabsorption

increasethirst

renin

increasedwater & saltreabsorption

high

Endocrine System Control

pituitary

angiotensinogenangiotensin

nephronadrenalgland

aldosterone

JuxtaGlomerularApparatus

AP Biology

Maintaining Water Balance

Low solutes

renin (from JGA) activatesangiotensinogen

angiotensin triggers aldosterone

aldosteroneincreases absorption

of NaCl & H2O in kidney

Oooooh,zymogen!

Low blood osmolarity level or low blood pressure

AP Biology

Maintaining Water Balance Low blood osmolarity level

or low blood pressure JGA releases renin in kidney renin converts angiotensinogen to angiotensin angiotensin causes arterioles to constrict

increase blood pressure angiotensin triggers release of aldosterone from

adrenal gland increases reabsorption of NaCl & H2O in kidneys

puts more water & salts back in blood

Get morewater & salt into

blood fast!

adrenalgland

AP Biology

Homeostasis Osmoregulation

solute balance & gain or loss of water Excretion

elimination of nitrogenous wastes

Thermoregulation maintain temperature within tolerable range

AP Biology

Maintaining Water Balance Monitor blood osmolarity

amount of dissolved material in blood

in brain

ADH = anti-diuretic hormone

High solutes