Exam 4 Student Learning Objectives

Chapter 41: Digestive System

Difference Between Heterotrophs and Autotrophs

• Heterotrophs: Obtain energy and nutrients from other organisms.
• Autotrophs: Synthesize own food using light, water, carbon dioxide, or other chemicals.

Essential Nutrients Required by Humans

• Amino Acids: 8 essential amino acids (9-10 in reality) required from diet.
• Vitamins: Organic, vital for health, needed in minute amounts.
• Electrolytes: Inorganic ions (Na+, K+, Cl-) important for osmotic balance and cell function.
• Minerals: Inorganic substances like Ca, Fe, Mg used as cofactors and structural materials.

Digestive Systems

• Incomplete Digestive Tracts: Single opening for ingestion and elimination (e.g., gastrovascular cavity).
• Complete Digestive Tracts: Separate mouth and anus; allows continuous processing and compartmentalization.

Structure and Function of Digestive Tract Segments

• Mouth: Mechanical breakdown and chemical digestion of carbohydrates and lipids.
• Esophagus: Conducts food to stomach via peristalsis.
• Stomach: Mechanical and chemical digestion of proteins; acid environment.
• Small Intestine: Major site of enzymatic digestion and nutrient absorption.
• Large Intestine: Water absorption and formation of feces.

Absorption and Surface Area

• Villi and Microvilli: Increase surface area in the small intestine for nutrient absorption.

Organs and Cells Involved in Digestion

• Salivary Glands: Produce amylase and mucins.
• Tongue Cells: Secrete lingual lipase.
• Chief Cells: Secrete pepsinogen.
• Parietal Cells: Secrete HCl.
• Mucous Cells: Secrete mucus.
• Pancreas: Secretes enzymes and bicarbonate.
• Liver: Produces bile.
• Gallbladder: Stores and secretes bile.
• Rumen and Reticulum: Hold symbiotic bacteria for cellulose digestion.

Digestive Enzymes

• Salivary Amylase: Carbohydrate digestion in mouth.
• Lingual Lipase: Lipid digestion in mouth.
• Pepsinogen/Pepsin: Protein digestion in stomach.
• Enterokinase: Activates trypsinogen in small intestine.
• Trypsinogen/Trypsin: Activates other proteases.
• Nucleases: Digest RNA and DNA.
• Pancreatic Amylase: Continues carbohydrate digestion.
• Pancreatic Lipase: Breaks down fats.

Chemical Digestion Locations

• Carbohydrates: Mouth (salivary amylase), small intestine (pancreatic amylase).
• Proteins: Stomach (pepsin), small intestine.
• Nucleic Acids: Small intestine.
• Lipids: Mouth (lingual lipase), small intestine (bile and pancreatic lipase).

Hormones Influencing Digestion

• Secretin: Stimulates pancreas for bicarbonate release.
• Cholecystokinin (CCK): Stimulates secretion of enzymes and bile.
• Gastrin: Stimulates HCl secretion.

Glucose Homeostasis

• Insulin: Lowers blood glucose.
• Glucagon: Raises blood glucose.
• Diabetes Mellitus:
  • Type I: No insulin production.
  • Type II: Insulin resistance.

Chapter 40: Osmoregulation and Excretion

Principles of Osmoregulation

• Osmoregulation: Control of water and solutes.
• Osmoconformers: Match external osmolarity.
• Osmoregulators: Regulate internal osmolarity.

Nitrogenous Waste

• Ammonia: Excreted by aquatic animals.
• Urea: Excreted by mammals/amphibians.
• Uric Acid: Excreted by reptiles/birds/insects.

Shark Rectal Gland

• Function: Secretes concentrated salt solutions; uses Na+/K+-ATPase.

Insect Adaptations for Water Conservation

• Cuticle: Waxy layer reduces water loss.
• Spiracles: Can close to conserve water.
• Malpighian Tubules: Form pre-urine, reabsorb water and ions.

Mammalian Kidney

• Renal Corpuscle: Filters blood, forms pre-urine.
• Proximal Tubule: Reabsorbs water, ions, nutrients.
• Loop of Henle: Establishes osmotic gradient.
• Distal Tubule & Collecting Duct: Regulate water/ion balance.

Chapter 42: Respiratory Systems

Fick’s Law of Diffusion

• Equation: Rate = k x A x (P2-P1)/D.

Oxygen Transport

• Partial Pressure: Gases move from high to low partial pressure.
• Water vs. Air: Water has lower oxygen content.

Respiratory System Structures

• Fish: Gills with countercurrent exchange.
• Mammals: Lungs with alveoli.
• Birds: Air sacs and parabronchi.
• Insects: Tracheae system.

Relation to Fick’s Law

• Variables:
  • k: Solubility/temp.
  • A: Surface area (alveoli, lamellae).
  • (P2-P1): Gradients (high O2, low CO2).
  • D: Thin epithelial layers.

CO2 and pH in Respiration

• CO2 increases, resulting in lower pH; sensed by medullary center.

Hemoglobin Role

• Function: Binds O2, buffers blood pH, transports CO2.

Hemoglobin Binding Curves

• Sigmoid Curve: Cooperative binding.

pH and Fetal Hemoglobin Effects

• Bohr Shift: Low pH/high temp decreases affinity.
• Fetal Hb: Higher O2 affinity.

pCO2 and pO2 in Tissues

• Active Tissues: High CO2, low O2 promote O2 unloading.

Analyze and Evaluate

Chapter 41: Digestive Dysfunctions

• Impact Analysis: Gallstones, diabetes, liver failure effects.

Chapter 40: Kidney Adaptations

• Evaluation: Adaptations like kangaroo rat's Loop of Henle.

Hormonal Effects

• Aldosterone & ADH: Regulation of water/ion reabsorption.

Chapter 42: Fick’s Law Applications

• Analysis: Gas exchange adaptations (e.g., bird lungs, fish gills).
• Flow Systems:
  • Countercurrent: Maintain strong gradient (e.g., fish gills).