animal phys ch 14 osmolarity

70%

excretory organ

substances that increase intercellular osmolarity; urea and trimethylamine oxide

occur in response to physical factors over which animals have no control

physiologically controlled serve  to maintain internal homeostasis

controls permeability of amphibian skin

utilized in kidneys of birds and mammals to produce hyperosmotic urine which is more concentrated than the blood plasma

hairpin like bend in kidney tubule, allows birds and mammals to exploit dry enviroments

can tolerate a wide range of salinites

can tolerate on a narrow osmotic range

hyperosmotic to their environment in the range of 200-300 mosm L-1. 1. subject to swelling 2. subject to loss of body salts

mediate transport of NaCl from the blood into the surrounding water

6 g

outer layer of the kidney

inner layer of the kidney, sends papillae into renal pelvis

renal pelvis goes to ureter that empties into urinary bladder. and micturition via the urethra

simultaneous contraction of the smooth muscle of the bladder wall and relaxation of the skeletal muscle sphincter around the opening of the bladder. as the bladder is stretched by filling, stretch receptors in the wall generate nerve impulses.

• functional unit of the kidney, intricate epithelial tube
• 80% cortical Nephron
• 20% juxtamedullary Nephron

each kidney contains numerous nephrons which empty into __

papillary ducts which empty into the renal pelvis

formed from tuft of capillaries inside bowman;s capsule. responsible for the first step in urine formation

incapable of producing urine that is hyperosmotic to the blood

have their glomeruli in the inner part of the cortex and long loops of henle that plunge deeply into the medulla

their glomeruli in the outer cortex and short loops of henle extend a short distance into the medulla

• -filtration of blood plasma to form ultrafiltrate in lumen of bowman's capsule
• -tubular reabsorption of approx 99% of water and most salts from the ultrafiltrate, left behind conc waste product
• -tubular secretion of number of substances, in nearly all instances via active transport

all of blood expect blood cells and blood protein. filtration 15-20% of water and solutes are removed

• -net hydrostatic pressure difference between the lumen of the glomerular capillaries and the lumen of bowman's capsule
• -colloid osmotic pressure of blood plasma
• hydraulic permeability of 3-layered tissue separating the two compartments

makes up the glomerulus, contains large pores that are 100x more permeable than the capilaries found in the body

• 1. extensive cellular dehydration results in impairment of metabolism
• 2. changes in ion composition of extracellular fluid results in malfunctions of failure of electrical mechanisms (AP mech in all cells;synaptic mech in neural tissues)
• 3. changes in pH affect all proteins and functions of all protein related mechs

similar to sea water

1/3 that of sea water (reflects freshwater origin of most vertebrates)

most important system involved in the regulation of extra cellular fluid and excretion of nitrogenous waste

• removal of soluble metabolic wastes
• regulation of composition of blood including blood volume
• homeostasis of extracellular fluid

• 1urea- 2N terrestrial vertebrates (ureotelic)
• ammonia 1N aquatic animals(teleosts) (ammonotelic)
• uric avid 4N birds and land reptiles (uricotelic)

• formed by catabolism of amino acids
• ammonia is toxic

• 1.via glutamate reaction (ammonia + glutamate >>glutamine)
• 2. some must excreted

• sea water    urine    nasal fluid
• 3%              3%       5%

• sea water    urine    nasal fluid
• 3%              2%       1%

2 kidneys, 2 ureters, 1 urinary bladder, 1 urethra

serous (highly vascularized), membrane of connective tissue, inside of abdominal walls and reflected over certain viscera

double layered peritoneal fold connecting intestines to posteror abdominal wall

cortex, medulla renal columns, pelvis

• 1. homeostasis of tissue fluids
• a. excretion of nitrogen waste
• b. maintenance of fluid volume (blood)
• c. maintenance of fluid composition
• d. assists in maintaining pH

• 2. endocrine function (hormones)
• a. makes erythroporetin (production of red blood cells in bone marrow)
• b. makes renin

• 1 renal corpuscle contains glomerulus in bowman's capsule
• 2. proximal convoluted tubule
• 3. loop of henle
• 4. distal convoluted tubule
• 5. collecting duct

• 1. filtration-bowman's capsule
• 2.reabsorbtion- proximal convoluted tubule 75% and distal convoluted tubule
• 3.secretion/synthesis - distal convoluted tubule
• 4. final concentration- collecting duct