BIO 133 exam 1 (Kidney)

what is excretory system

removes excess waste, unnecessary, or toxic waste to maintain homeostasis

what are some functions of excretory system

• regulation of extracellular fluid

• regulation of blood pressure

• regulation of osmolairty

• regulation of pH

• excretion of waste

• production of hormoes

what are osmoconformers

• aquatic organisms that maintain internal osmotic pressure equal to the surrounding environment

what are asmoregulators

organism maintain stable internal salt and water concentration regardless on enviornment due to kidney

what is the functioning unit of kidney

nephron

what is the nitrogenous waste of most aquatic organism

NH3 (amonia)

what is the nitrogenous waste of mammals and sharks

urea

what is the nitrogenous waste of reptiles and insects

uric acid

from what organism did the kidney evolve from

freshwater fish

what are the functions of the kidney

1. filtration

2. reabsorption

3. secreation

what happens during filtration

• fluid in the blood id filtered out of the glomerulus into the tubule system

• proteins and blood cells stay in blood, should not be in urine

what happens during reabsorption

selective movement of solute out of the filtrate back into the blood via peritubular capillaries

what happens during secretion

kidneys move unwanted substances from the blood into the urine

Detailed Sequence of Nephron Parts

1. Renal Corpuscle

   • Glomerulus

   • Bowman's Capsule

2. Proximal Convoluted Tubule (PCT)

3. Loop of Henle (Nephron Loop)

4. Distal Convoluted Tubule (DCT)

5. Collecting Duct

what is the function of Renal Corpuscle

initial site of blood filtration

what is the function of Glomerulus

• Initial, high-pressure filtering unit, separating water, ions, and waste from blood plasma while retaining essential cells and large proteins

what is the function of Proximal Convoluted Tubule (PCT)

• maintains blood pH

• regulates electrolyte balance

• secretes waste products

what is the function of Loop of Henle (Nephron Loop)

concentrate urine by reabsorbing water and sodium chloride () from the filtrate

what is the function of Collecting Duct

processes filtrate and playing a critical role in fluid balance

what is the function of Bowman's Capsule

collects from glomerulus filtrate to pass it into the nephron

what is the function of descending limb of henle

• highly permeable to water but not solutes

• causing urine to become hypertonic as water leaves via osmosis

What is function of ascending limb of henle

• impermeable to water but actively pumps out salts

• making urine

what is the Antideirtic Hormone (ADH)

• caused by increased blood concentration (high osmolality) or decreased blood volume/pressure (hypovolemia)

• relcaims water into the body

• produced by the hypothalamus and stored in the parathyroid glands

what is the function of aldosterone

• stimulated by low levels of Na+ in blood(low blood pressure)

• causes distal convoluted tube and collection duct to reabsorbes Na+

• secreted by adrenal glands

• brings water back into the body

what is Atrial natriuretic hormone (ANH)

• moves salt to get rid of water (opposite of aldostrone)

• when blood pressure is to high

what is negative feedback

self-regulated control mechanism system where output reduced or counteracts initial stimulus

what is postive feedback

amplified moving system further away from initial state rather than returning to homestasis

what do thepituitary glands produce and secreat

• growth hormone

• thyroid stimulating hormone

• adrencorticotpic hormone (ACTH)

• ADH

thyroid glands

produce hormones that control metabolism

adrenal glands

produce hormones like cortisol and adrenal for stress response