The document discusses homeostasis and the roles of the liver and kidneys in maintaining it. The liver regulates blood composition, stores glucose as glycogen, and creates the nitrogenous waste urea. It will test blood vessels involved in digestion for glucose levels before and after eating, hypothesizing the hepatic portal vein will have higher levels after eating. The kidneys filter waste from the blood and regulate water and salt levels through processes like filtration, reabsorption, and secretion in nephrons.

1. HOMEOSTASIS
• The body maintains a constant internal environment
• All internal organs interact to maintain homeostasis
• We will focus on liver, and kidneys

2. LIVER STRUCTURE
• Two lobes
• Right is larger
• Divided into lobules
• Contain hepatic cells
• Hepatic vein: transport O2
poor blood out
• Hepatic artery: transports
O2 rich blood in
• Hepatic portal vein:
transport blood with
nutrients from intestines to
liver
• Bile duct: transports bile to
gallbladder

3. LIVER AND HOMEOSTASIS
• Regulates blood composition
• Stores glucose as glycogen
• Creates the nitrogenous waste urea
• With high blood glucose levels, pancreas secretes
insulin
• Liver takes up glucose and stores as glycogen
• With low blood glucose levels, hormone glucagon breaks
down glycogen releasing glucose

5. EXPERIMENT
• We will test three different blood vessels involved in
digestion/storage for glucose:
• – Hepatic vein
• – Hepatic portal vein,
• Mesenteric artery (leads to the intestine).
• We will test each before and after eating
• Form a hypothesis: Which blood vessel would we expect
to have high glucose levels before eating? After?

6. BENEDICT’S TEST
• Needs to be heated for 5 minutes
• Wear goggles.
• Benedict’s turns from blue to a red color in the presence
of glucose
• Blue → green → yellow → orange → red

7. KIDNEYS
• Filtering organ of our body
• Produce urine (nitrogenous waste)
• Get rid of excess water and salts (osmoregulation)
• Maintain pH

8. NEPHRON: FUNCTIONING UNIT
• Filters water and salts
and sugars from the
blood
• Does not remove blood
cells or proteins

9. KIDNEY FUNCTION: 4 PROCESSES
• Filtration: Bowman’s capsule: molecules move out of
glomergulus into capsule
• Reabsorption: in proximal tubule
• Glucose and amino acids get reabsorbed
• Secretion: Certain substances, like histamines, H + and
ammonia get secreted into nephron tube from peritubular
capillaries
• Water reabsorption: Loop of Henle and collecting duct

10. KIDNEY FUNCTION: OSMOREGULATION
• Salt and water balance
• Hormone: ADH from
pituitary gland
• Changes permeability of the
collecting duct
• Can absorb more of less
water as a result

11. KIDNEY FUNCTION: PH
• Can remove excess acids (H+) or bases (bicarbonate)
through urine production
H+ + HCO3
– ↔ H2CO3 ↔ CO2 + H2O