Notes on the structure, function, and processes involved in the human kidney

-Blood enters each kidney via renal artery and leaves each kidney via renal vein

-Urine exists the kidney through a duct called the ureter and the uruters of both kidneys drain into a common urinary bladder

-Kidney consists of outer renal cortex and inner renal medulla

-Nephron is functional unit of vertebrate kidney

-Consists of single long tubule and ball of capillaries called the glomerulus

-Bowman's capsule surrounds the glomerulus

-Kidney regulates the composition of the blood and produce urine

-Filtration occurs as blood pressure forces water, urea, salts, and other small solutes from the blood in the glomerulus into the Bowman's capsule

-Nonselective

-Filtrate goes into proximal tube, loop of Henle (a hairpin turn with a descending limb and ascending limb) and the distal tubule

-Kidney consists of cortical nephrons and juxtamedullary nephrons (only in mammals and birds)

-Most of filtrate is reabsorbed back into blood; the kidneys take out about 1%

-Proximal and distal tubules are the most common sites of secretion

-Very selective process with both passive and active transport of solutes

-Proximal, distal tubules, and loop of Henle contribute to Reabsorption

-Collecting duct also helps in Reabsorption

-Mammalian's kidney's ability to conserve water is considered an important adaptation

-Antidieretic hormone is important in osmoregulation

-Made in hypothalamus and released when osmolarity in blood rises above certain point

-ADH acts on the distal tubules and collecting ducts by increasing their permeability to water

-Causes more water Reabsorption

-Is turned off through negative feedback

-Juxtaglomerulur apparatus located in the vicinity of the afferent arteriole, which supplies blood to the glomerulus

-When blood pressure or blood volume in the afferent arteriole drops, the enzyme rennin causes chemical reactions that create a peptide called angiotensin II

-Angiotensin II increases blood pressure and blood volume by constricting arterioles and decreasing blood flow to many capillaries like the kidney

-Causes more salt and water reabsorption to increase blood volume

-Causes release of aldosterone, which also acts on nephron's distal tubules and helps, reabsorb more sodium and water

-Negative feedback turns rennin production off

-Called the rennin-angiotensin-aldosterone system

-Atrial natriuretic factor opposes RAAS

-Released by the heart in response to an increase in blood volume and pressure

-Inhibits the release of rennin

-Inhibits NaCl reabsorption and reduces aldosterone release from adren