BIO 121 – Unit 4 Cram Guide with Hybrid

Mnemonics

Digestive System & Metabolism

Chapter 24 – Digestive System Anatomy

Accessory Organs & Basic Concepts

Main Job: Break food down mechanically + chemically → absorb nutrients → eliminate waste. Accessory

Organs: Salivary glands, liver, gallbladder, pancreas. Absorption: Digested nutrients → bloodstream/lymph.

Food Pathway: Oral Cavity → Pharynx → Esophagus → Stomach → Small Intestine → Large Intestine →

Rectum → Anus

Mnemonic: “SLiP Along Food Slowly Like Real Ants” - S = Salivary glands - L = Liver - P = Pancreas - Food

pathway: Oral → Pharynx → Esophagus → Stomach → SI → LI → Rectum → Anus

Quick Check: Name the four accessory organs; define absorption; what connects stomach → small

intestine?

Layers of the Alimentary Canal

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Mucosa: secretion, absorption, protection

Submucosa: connective tissue with vessels/nerves

Muscularis: peristalsis

Serosa: outermost covering

Mnemonic: “My Silly Monkey Sings” (Mucosa, Submucosa, Muscularis, Serosa)

Quick Check: Which layer performs peristalsis? What’s in submucosa?

Peritoneum & Mesenteries

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Greater Omentum: fat apron

Lesser Omentum: stomach → liver

Mesenteries: suspend intestines, carry vessels/nerves

Mnemonic: “Giant Little Monkeys” (Greater Omentum, Lesser Omentum, Mesenteries)

1Quick Check: Function of greater omentum? What connects small intestine → posterior wall?

Oral Cavity

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Tongue: Intrinsic = shape, Extrinsic = movement

Parotid Glands: anterior to ear, upper 2nd molar

Saliva: lubrication, taste, protection, amylase/lipase

Teeth: Enamel = hard, Dentin = bulk, Cementum = anchors

Mnemonic: “I Eat Sweet Candy” (Intrinsic, Enamel, Saliva, Cementum)

Quick Check: Which gland is largest? What enzyme starts starch digestion?

Pharynx & Esophagus

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Epiglottis: covers glottis

Esophagus: peristalsis

Mnemonic: “Eat Every Sandwich” (Epiglottis, Esophagus, Swallowing)

Quick Check: What structure guards airway?

Stomach

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Layers: oblique, circular, longitudinal

Cells: Mucous, Parietal (HCl + intrinsic factor), Chief (pepsinogen), G cells (gastrin)

Pyloric Sphincter: controls emptying

Mnemonic: “My Pretty Cat Grows” (Mucous, Parietal, Chief, G cells)

Quick Check: Name 2 cell types + secretions; function of pyloric sphincter

Small Intestine

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Regions: Duodenum → Jejunum → Ileum

Absorptive Cells: microvilli = brush border

Duodenal Glands: alkaline mucus

Ileocecal Valve: controls flow to LI

Mnemonic: “Don't Jump In” (Duodenum, Jejunum, Ileum)

Quick Check: What is brush border? Function of duodenal glands?

2Liver, Gallbladder, Pancreas

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Pancreas: acinar = enzymes, duct = bicarbonate

Liver: bile, glycogen/vitamins, detox, plasma proteins

Gallbladder: stores/concentrates bile

Mnemonic: “Lazy Penguins Bake Cookies” (Liver, Pancreas, Bile, Concentration)

Quick Check: Which organs make vs store bile? Function of portal system?

Large Intestine

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Absorbs water, electrolytes, vitamins (K, B5)

Haustra: segmental churning

Defecation Reflex: rectal stretch → spinal reflex → internal sphincter relax

Mnemonic: “Happy Dogs Dig Food” (Haustra, Defecation reflex, Digestion, Feces)

Quick Check: Vitamins made by gut flora? Define defecation reflex

Motility & Digestion

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Peristalsis: wave-like contractions

Mechanical: mastication, segmentation

Chemical: enzymes → monomers

Absorption: nutrients in small intestine, fats via lymph

Mnemonic: “People Make Chocolate Always” (Peristalsis, Mechanical, Chemical, Absorption)

Quick Check: Define peristalsis; movement mixes chyme in SI?

Regulation

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CCK: stimulates pancreas & gallbladder

Secretin: bicarbonate secretion

Mnemonic: “Cats Sit” (CCK, Secretin)

Quick Check: Role of CCK? Role of Secretin?

3Chapter 25 – Metabolism

Carbohydrate Metabolism

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Anabolism: build molecules

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Catabolism: break down molecules

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Insulin: glucose uptake & storage

Mnemonic: “A Cute Iguana” (Anabolism, Catabolism, Insulin)

Quick Check: Define anabolism vs catabolism; insulin function

Glycolysis & Respiration

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Glycolysis: cytoplasm → 2 pyruvate + 2 ATP + NADH

Anaerobic: lactic acid (low ATP)

Aerobic: Krebs + ETC → ~36 ATP

Mnemonic: “Great Ants Attack” (Glycolysis, Anaerobic, Aerobic)

Quick Check: Where does glycolysis occur? What happens when O₂ absent?

Other Carb Pathways

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Gluconeogenesis: new glucose from AA/glycerol

Glycogenesis: glucose → glycogen

Glycogenolysis: glycogen → glucose

Mnemonic: “Good Girls Go” (Gluconeogenesis, Glycogenesis, Glycogenolysis)

Lipid Metabolism

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Triglycerides: glycerol + 3 FAs

β-Oxidation: FA → acetyl-CoA

Ketone Bodies: formed when fat used excessively

Mnemonic: “Tasty Brown Kiwis” (Triglycerides, β-Oxidation, Ketones)

Quick Check: Define β-oxidation; why ketones form?

Temperature Regulation

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Hypothalamus: thermostat

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Heat gain: vasoconstriction, shivering

Heat loss: vasodilation, sweating

Mnemonic: “Hot Guys Hate” (Hypothalamus, Gain, Heat loss)

Quick Check: Which structure controls temperature? How does body respond to overheating?