Anatomy & Physiology: Digestive & Urinary System and Fluid Balance

Flashcards of key vocabulary and concepts from the lecture notes.

Ingestion

Taking food into GI tract

Propulsion

Movement of food through GI tract

Mechanical Breakdown

Physical processing of food

Chemical Digestion

Enzymatic breakdown of food

Absorption

Movement of digested end products into blood/lymph

Defecation

Elimination of indigestible substances

Alimentary Canal (GI Tract)

Continuous muscular tube from mouth to anus

Accessory Digestive Organs

Teeth, tongue, salivary glands, liver, gallbladder, pancreas

Mucosa

Layer of GI tract responsible for secretion, absorption, and protection. Consists of epithelium, lamina propria, and muscularis mucosae

Serosa

Layer of GI tract made up of visceral peritoneum (connective tissue) and functions in protection and reducing friction

Myenteric Nerve Plexus

Intrinsic nerve plexus in the GI tract.

Submucosal Nerve Plexus

Intrinsic nerve plexus in the GI tract.

Salivary Glands

Parotid, submandibular, sublingual glands; produce saliva containing amylase, lingual lipase, and lysozyme

Deglutition

Swallowing

Buccal Phase

Voluntary phase of swallowing, bolus forced into oropharynx

Pharyngeal-Esophageal Phase

Involuntary, reflex-controlled phase of swallowing

Rugae

Mucosal folds in the stomach when empty

Intrinsic Factor

Secreted by the stomach; essential for Vitamin B12 absorption

Gastrin

Hormone regulating gastric secretion; increases HCl secretion and stimulates contraction of intestinal muscle

Cephalic Phase

Phase of gastric activity before food enters stomach (sight, smell, thought of food)

Gastric Phase

Phase of gastric activity when food is in the stomach (distension, protein presence)

Intestinal Phase

Phase of gastric activity when food is entering the duodenum (initially stimulates, then inhibits)

Liver

Produces bile (emulsifies fats), stores fat-soluble vitamins, processes blood-borne nutrients, and performs detoxification

Gallbladder

Stores and concentrates bile, and releases bile in response to CCK to aid in eating fats

Pancreas

Exocrine function: Produces pancreatic juice with digestive enzymes and bicarbonate; Endocrine function: produces insulin and glucagon.

CCK and Secretin

Control the pancreas

Small Intestine

Major site of digestion and absorption

Circular Folds (Plicae Circulares)

Structural modification of the small intestine

Villi

Finger-like projections lining the small intestine

Microvilli

Brush border of the small intestine; increase the surface area and allow for a greater volume of filtrate components to be reabsorbed

Enterocytes

Absorption cells in the small intestine

Goblet Cells

Mucus-secreting cells in the small intestine

Enteroendocrine Cells

Hormone-producing cells in the small intestine

Paneth Cells

Antimicrobial secretion cells in the small intestine

Segmentation

Mixing movements in the small intestine

Peristalsis

Propulsion movements in the small intestine

Large Intestine

Functions: Water absorption, formation/storage of feces, bacterial fermentation

Salivary Amylase

Source: Salivary glands; Site of Action: Mouth, upper stomach; Substrate: Starch, glycogen; End Products: Maltose, small polysaccharides

Pancreatic Amylase

Source: Pancreas; Site of Action: Small Intestine; Substrate: Starch, glycogen; End Products: Maltose, maltotriose, a-limit dextrins

Brush Border Enzymes

Source: Small Intestine; Site of Action: Small Intestine; Substrate: Disaccharides; End Products: Monosaccharides

Pepsin

Source: Stomach; Site of Action: Stomach; Substrate: Proteins; End Products: Peptides

Trypsin, Chymotrypsin, Elastase

Source: Pancreas; Site of Action: Small Intestine; Substrate: Proteins, peptides; End Products: Smaller peptides

Carboxypeptidase

Source: Pancreas; Site of Action: Small intestine; Substrate: Peptides; End Products: Amino acids

Aminopeptidase

Source: Small intestine; Site of Action: Small intestine; Substrate: Peptides; End Products: Amino acids

Di- and tripeptidases

Source: Small intestine; Site of Action: Small intestine; Substrate: Dipeptides, tripeptides; End Products: Amino acids

Gastrin

Source: G cells (stomach); Stimulus: Proteins, stomach distension; Target: Stomach; Effect: ↑ HCl, pepsinogen secretion, stimulates contraction of intestinal muscle

Cholecystokinin (CCK)

Source: I cells (small intestine); Stimulus: Fats, proteins; Target: Pancreas, Gallbladder; Effect: ↑ Enzyme secretion, ↑ bile release

Secretin

Source: S cells (small intestine); Stimulus: Acidity in duodenum; Target: Pancreas, Liver; Effect: ↑ Bicarbonate secretion

Motilin

Source: Small intestine; Stimulus: Fasting; Target: GI tract; Effect: Initiates migrating motor complex

My Students Made Soup

Mnemonic for GI Tract Layers (inside to outside): Mucosa, Submucosa, Muscularis, Serosa

CGI Effects

Mnemonic for the Phases of Gastric Secretion: Cephalic, Gastric, Intestinal

DJI Drone

Mnemonic for Small Intestine Divisions: Duodenum, Jejunum, Ileum

Urinary System

Primary Function: Maintain homeostasis of body fluids by regulating Volume and composition of blood, Blood pressure, Red blood cell production (via erythropoietin), Vitamin D activation, and Waste elimination

Nephron

Functional unit of kidney (1-1.2 million per kidney)

Renal Corpuscle

Major component of a nephron; Glomerulus (capillary tuft) and Glomerular (Bowman's) capsule produces protein-free filtrate

Renal Tubule

Major component of a nephron; Proximal Convoluted Tubule (PCT) is a major reabsorption site, Nephron Loop (Loop of Henle), Distal Convoluted Tubule (DCT), Collecting Duct

Juxtaglomerular Complex (JGC)

Major component of a nephron; Macula Densa monitors NaCl content, Granular Cells monitor blood pressure and secrete renin

Cortical Nephrons

85% of nephrons; Located in cortex

Juxtamedullary Nephrons

15% of nephrons; Deeper, with long loops of Henle

Glomerular Filtration

Blood filtration across glomerular membrane

Tubular Reabsorption

Selective movement of filtrate components back to blood

Tubular Secretion

Movement of substances from blood to tubule; Functions: Eliminates waste products, Disposes of excess K+, Regulates blood pH

Glomerular Filtration Rate (GFR)

Rate of the filtration of blood across the glomerular membrane

Myogenic Mechanism:

Stretch-induced arteriole contraction

Tubuloglomerular Feedback

Macula densa monitors NaCl

RAAS

Renin-Angiotensin-Aldosterone System; triggered by low BP

ADH

Antidiuretic Hormone; Released from posterior pituitary in response to ↑ Plasma osmolality or ↓ Blood volume/pressure

Aldosterone

Released from adrenal cortex; Stimulated by: Angiotensin II, ↑ K levels, ACTH

ANP

Atrial Natriuretic Peptide; Released from cardiac atria when stretched

Micturition

Urination

Renal Clearance

Volume of plasma cleared of a substance per minute

Proteinuria

Protein in urine

Glycosuria

Glucose in urine

Ketonuria

Ketones in urine

Hematuria

Blood in urine

Oliguria

Low urine output (<500 mL/day)

Polyuria

Excessive urine output

Total Body Water

60% of body weight in adult males and 50% of body weight in adult females

Intracellular Fluid (ICF)

~40% of body weight (fluid inside the cell)

Extracellular Fluid (ECF)

~20% of body weight (fluid outside the cell)

Plasma

~5% of body weight; component of ECF

Interstitial Fluid

~15% of body weight; component of ECF

Electrolytes

Substances that dissociate into ions in solution

Hydrostatic pressure

Drives filtration

Colloid osmotic pressure

Drives reabsorption

Thirst Mechanism

Triggered by: ↑ Plasma osmolality (2-3%), ↓ Blood volume (10-15%), Angiotensin II

Dehydration

Water output > input

Hypotonic Hydration

Excess water intake

Edema

Fluid accumulation in tissues

Sodium

Principal ECF cation; Determines ECF volume; Influences neural excitability; Affects blood pressure

Potassium

Principal ICF cation; Critical for membrane potential; Affects cardiac function; H+ buffer

PTH

Parathyroid Hormone; Released when Ca²+ low

Calcitonin

Released when Ca²+ high; Inhibits Ca2+ release from bone; Antagonizes PTH effects

Acidosis

pH < 7.35

Alkalosis

pH > 7.45

ROME

Mnemonic for Interpreting Blood Gases; Respiratory acidosis: ↑ CO2, Opposite (Respiratory alkalosis): ↓ CO2, Metabolic acidosis: ↓ HCO3, Excessive base (Metabolic alkalosis): ↑ HCO3