Osmoregulation and Excretion 22 April 20151Osmoregulation.ppt

Osmoregulation and Excretion

22 April 2015 1Osmoregulation.ppt

Animal Life

22 April 2015 Osmoregulation.ppt 2

• Multicellular organisms• Internal circulation

• Coordination, information transfer

• Structural maintenance

• Movement

• Maintenance of homeostatic internal environment• Excretion of N waste

• Regulation of pH


How neurons conduct impulses:• Membrane potential (in

neurons, muscle cells, etc.)

• K+ diffuses out, Na+ diffuses in,

• Na-K pump moves Na+ out & K+ in.

• Cl-, phosphate, protein anions balance cations

• “Resting potential” = - 70 mV

Imbalance of electrolytes results in serious disorders


Osmoregulation

• Maintaining osmotic homeostasis• Balancing water and

electrolyte concentrations

• Maintains cell integrity

• Maintains enzyme function

• etc.


Osmosis

• Diffusion of water from high water concentration to lower water concentration.• Water loss

• Water gain


Osmosis Marine fish lose water by osmosis• Actively excrete salt to maintain homeostasis

Freshwater fish gain water by osmosis • Excrete excess water

Nitrogenous wastes


• Produced from metabolism of amino acids and nucleic acids• Ammonia

• Urea

• Uric acid

• Guanine• Arachnids

Nitrogenous wastes


• Produced from metabolism of amino acids and nucleic acids• Uric acid from birds

Nitrogenous waste & Osmoregulation

• Same systems balance water and dispose of nitrogenous wastes • Protonephridia & “flame

bulbs” in flatworms

• Metanephridia in annelids

• Malpighian tubules in arthropods


Humans

• Body Water• 75% of body weight in infant• 60% of body weight in adult male • 55% of body weight in adult female– Reasons for differences ??



Osmoregulation

• Fluid compartments”• Intracellular fluid

• Extracellular fluid• Interstitial (tissue)

fluid

• Blood plasma

• Lymph

Osmoregulation

• Exchanges among compartments• Intracellular – interstitial• Diffusion, facilitated diffusion, osmosis, active

transport

• Interstitial fluid (excess) lymph • Lymph blood plasma• Plasma interstitial fluid

• Filtration from capillaries carries electrolytes & nutrients to cells


Osmoregulation


• Regulation of blood plasma regulates all body fluids

• Parts of osmoregulation• Filtration

• Reabsorption

• Secretion

• Excretion (disposal)

Kidney


• NephronRenal corpuscle

• Glomerulus

• Bowman’s capsule

Tubule• Proximal convoluted

tubule

• Loop of Henle

• Distal convoluted tubule

Nephron

• Filtration in renal corpuscle • Afferent arteriole

• Glomerular capillaries

• Podocytes of Bowman’s capsule

• Efferent arteriole


Osmoregulation

• Reabsorption in proximal convoluted tubule • Active transport of Na+

• Co-transport of glucose, amino acids, etc.

• Cl- follows Na+

• Osmosis of water

• Diffusion of non-polar molecules

• Diffusion of urea


Osmoregulation


• Loop of Henle • Concentration of

salts in medulla of kidney

Osmoregulation


• Reabsorption and tubular secretion in distal convoluted tubule• Recovery of NaCl,

water,

• Reabsorption of HCO3-

• Secretion of H+, K+

• pH regulation • Sources of metabolic H+

Osmoregulation


• Collecting duct• Filtrate/urine makes

one more pass through medulla• Final reabsorption

(or not)

Osmoregulation

• Antidiuretic hormone (ADH) • Causes recovery of water

• Absence excretion of water

• Important for water homeostasis


OsmoregulationDiuretics

• Ethyl alcohol– Beer, wine, liquor

– Inhibits ADH release• Water NOT recovered

• Caffeine– Coffee, tea, Coke, etc.

– Inhibits Na+ transport• Sodium, water, etc.

NOT recovered


Urine Drainage

• Collecting ducts to • Minor calyx• Major calyx• Renal pelvis• Ureter


Urine Drainage

• Ureter to Urinary bladder

• Detrusor muscle• Smooth muscle of

bladder

• Urethra• internal sphincter

• external sphincter


Urine Drainage

• Urethra• internal sphincter

• external sphincter

• Female• 3-4 cm

• Anterior to vagina

• Male• 15-20 cm

• Passes through prostate and penis


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Osmoregulation and Excretion 22 April 20151Osmoregulation.ppt