Excretory System New Song https www youtube comwatch

Excretory System!

New Song! https: //www. youtube. com/watch? v=K 3 Z-Lt 58 H 0 s

Homeostasis Excretory system maintains homeostasis by balancing the amount of water, salt, and metabolite concentrations within the blood.

Not just the Kidney’s! Lungs: Remove CO 2 Skin: Removes heat Liver: Removes metabolic wastes and creates bile and urea Kidney: Removes metabolic wastes

Mammalian Kidney inferior vena cava aorta adrenal gland kidney ureter bladder urethra nephron renal vein & artery microvilli on epithelial cells

http: //handsonscience. jimdo. com/online-games-andactivities/unit-4 -breathing-circulation-and-excretion/

Mastering biology

http: //www. youtube. com/watch? v=8 UVl. XX-9 x 7 Q

Mammalian System blood filtrate Filter solutes out of blood & reabsorb H 2 O + desirable solutes Key functions filtration fluids (water & solutes) filtered out of blood reabsorption selectively reabsorb (diffusion) needed water + solutes back to blood secretion pump out any other unwanted solutes to urine excretion expel concentrated urine (N waste + solutes + toxins) from body concentrated urine

Nephron § Functional units of kidney u 1 million nephrons per kidney § Function u u filter out urea & other solutes (salt, sugar…) blood plasma filtered into nephron § high pressure flow u selective reabsorption of valuable solutes & H 2 O back into bloodstream § greater flexibility & control why selective reabsorption & not selective filtration? “counter current exchange system”

How can different sections allow the diffusion of different molecules? Mammalian kidney Interaction of circulatory & excretory systems Circulatory system Bowman’s glomerulus = ball of capillaries capsule Proximal tubule Distal tubule Glomerulus Excretory system nephron Bowman’s capsule loop of Henle proximal tubule descending limb ascending limb distal tubule collecting duct Glucose Amino acids H 2 O Mg++ Ca++ H 2 O Na+ Cl- H 2 O Na+ Cl. H 2 O Loop of Henle Collecting duct

Nephron: Filtration At glomerulus filtered out of blood H 2 O & solutes H 2 O glucose salts / ions (Na+ / Cl–) urea not filtered out cells & large molecules cells proteins high blood pressure in kidneys force to push (filter) H 2 O & solutes out of blood vessel BIG problems when you start out with high blood pressure in system hypertension = kidney damage

Nephron: Re-absorption Proximal tubule reabsorbed back into blood Na. Cl active transport of Na+ Cl– follows by diffusion H 2 O glucose HCO 3 - bicarbonate buffer for blood p. H

Nephron: Re-absorption § Loop of Henle descending limb u reabsorbed § H 2 O u structure u § many aquaporins in cell membranes § high permeability to H 2 O § no Na+ or Cl– channels § impermeable to salt structure fits function!

Nephron: Re-absorption § Loop of Henle ascending limb u reabsorbed § Na+ & Cl– u structure u § many Na+ / Cl– channels in cell membranes § high permeability to Na+ & Cl– § no aquaporins § impermeable to H 2 O structure fits function!

Nephron: Re-absorption § Distal tubule u reabsorbed § salts § H 2 O § bicarbonate w HCO 3 w regulate blood p. H

Nephron: Reabsorption & Excretion § Collecting duct u reabsorbed § H 2 O = through aquaporins u excretion § concentrated urine § to bladder w impermeable lining = no channels in cell membranes

Osmotic control in nephron How is all this re-absorption achieved? tight osmotic control to reduce the energy cost of excretion use diffusion instead of active transport wherever possible the value of a counter current exchange system

why selective reabsorption & not selective filtration? Summary Not filtered out of blood cells u proteins remain in blood (too big) Reabsorbed back to blood: active transport Na+ u glucose u amino acids Reabsorbed back to blood: diffusion H 2 O u Cl– Excreted out of body urea excess H 2 O u excess solutes (glucose, salts) toxins, drugs, “unknowns”