Digestive System

Mouth

The mouth is the entry point for food into the digestive system and is responsible for mechanical and chemical digestion.

• Labia: The lips, which help contain food within the oral cavity.

• Oral cavity: The space inside the mouth where food is mixed with saliva.

• Hard palate: The bony anterior portion of the roof of the mouth, separating the oral and nasal cavities.

• Soft palate: The posterior, muscular portion of the palate, important in swallowing.

• Teeth: Structures for mechanical breakdown of food.

  • Dentin: The main, calcified tissue of the tooth beneath the enamel.

  • Enamel: The hard, outer surface layer of the tooth.

  • Root canal: The passage within the root containing nerves and blood vessels.

  • Cementum: The calcified layer covering the tooth root.

  • Periodontal ligament: Connective tissue anchoring the tooth to the alveolus.

  • Alveolus: The socket in the jawbone where the tooth sits.

  • Gingiva: The gums surrounding the teeth.

• Uvula: The small, fleshy extension at the back of the soft palate, helps prevent food from entering the nasopharynx.

• Salivary glands: Produce saliva for digestion and lubrication.

  • Parotid

  • Sublingual

  • Submandibular

• Frenulum: Folds of tissue that anchor the tongue and lips.

  • Lingual

  • Superior labial

  • Inferior labial

Oropharynx and Esophagus

The oropharynx is the part of the throat behind the mouth, leading to the esophagus, which transports food to the stomach.

• Oropharynx: Passageway for food and air.

• Esophagus: Muscular tube connecting the pharynx to the stomach.

Stomach

The stomach is a muscular organ that continues mechanical and chemical digestion.

• Lesser curvature: The inner curve of the stomach.

• Greater curvature: The outer curve.

• Rugae: Folds in the stomach lining that allow expansion.

• Cardia: Region where the esophagus enters the stomach.

• Fundus: Dome-shaped upper portion.

• Body: Main central region.

• Pyloric region: Distal region leading to the small intestine.

• Pyloric sphincter: Valve controlling passage of food into the duodenum.

Small Intestine

The small intestine is the primary site for digestion and absorption of nutrients.

• Duodenum: First segment, receives chyme and digestive enzymes.

• Jejunum: Middle segment, major site of absorption.

• Ileum: Final segment, absorbs remaining nutrients.

• Ileocecal junction: Where the ileum meets the cecum of the large intestine.

Large Intestine

The large intestine absorbs water and forms feces.

• Haustra: Pouches in the colon wall.

• Cecum: First part of the large intestine.

• Appendix: Small, tube-like structure attached to the cecum.

• Colon: Four segments: ascending, transverse, descending, sigmoid.

• Rectum: Terminal segment for feces storage.

• Anus: Exit point for feces.

Accessory Digestive Organs

• Pancreas: Produces digestive enzymes and hormones.

  • Head

  • Tail

  • Main pancreatic duct

  • Accessory pancreatic duct

• Liver: Produces bile, processes nutrients.

  • Lobes: Right, left, caudate, quadrate

  • Hepatic ducts: Left and right

  • Common hepatic duct

  • Bile duct

  • Falciform ligament: Separates right and left lobes

• Gallbladder: Stores and concentrates bile.

  • Cystic duct

Urinary System

Kidney

The kidneys filter blood, remove waste, and regulate fluid balance.

• Hilum: Entry/exit for ureter, renal artery, and renal vein.

• Cortex: Outer region containing nephrons.

• Medulla: Inner region with renal pyramids.

• Renal pyramids: Cone-shaped structures in the medulla.

• Papillae: Tips of pyramids where urine drains.

• Calyx: Collects urine; major and minor types.

• Renal pelvis: Funnel-shaped reservoir for urine before entering ureter.

Ureters, Bladder, and Urethra

These structures transport, store, and expel urine.

• Ureters: Tubes carrying urine from kidneys to bladder.

• Urinary bladder: Muscular sac for urine storage.

• Trigone: Triangular area in bladder between ureter openings and urethra.

• Internal urethral sphincter: Involuntary muscle controlling urine flow.

• External urethral sphincter: Voluntary muscle for urine control.

Male Reproductive System

Testes and Associated Structures

The testes produce sperm and hormones; associated structures support sperm maturation and transport.

• Tunica vaginalis: Outer covering of testes.

• Tunica albuginea: Fibrous capsule surrounding testes.

• Seminiferous tubules: Site of sperm production.

• Rete testis: Network collecting sperm from tubules.

• Scrotum: External sac holding testes.

• Epididymis: Sperm maturation and storage; divided into head, body, tail.

• Vas deferens: Duct transporting sperm.

• Spermatic cord: Contains vas deferens, blood vessels, nerves.

• Cremaster muscle: Regulates testicular temperature.

Accessory Glands and Penis

• Seminal vesicle: Secretes fluid for sperm.

• Ejaculatory duct: Passage for sperm and seminal fluid.

• Prostate gland: Adds fluid to semen.

• Prostatic urethra: Urethra segment within prostate.

• Membranous urethra: Short segment between prostate and penis.

• Bulbourethral gland: Secretes lubricating fluid.

• Penis: Organ for copulation and urination.

  • Penile (spongy) urethra

  • Corpora cavernosa: Erectile tissue

  • Corporus spongiosum: Surrounds urethra

  • Glans: Distal end

  • Prepuce: Foreskin

Female Reproductive System

Ovaries and Uterine Tubes

The ovaries produce eggs and hormones; uterine tubes transport eggs to the uterus.

• Ovaries: Female gonads.

• Uterine (Fallopian) tubes: Pathway for egg.

  • Isthmus: Narrow segment

  • Ampula: Expanded region, site of fertilization

  • Infundibulum: Funnel-shaped end

  • Fimbriae: Finger-like projections

Uterus and Associated Structures

• Uterus: Site of fetal development.

  • Endometrium: Inner lining

  • Myometrium: Muscular layer

  • Perimetrium: Outer layer

  • Fundus: Upper rounded portion

  • Ovarian ligament: Connects ovary to uterus

  • Broad ligament: Supports uterus, ovaries, tubes

  • Round ligament: Supports uterus

  • Cervix: Lower part; internal and external Os are openings

• Vagina: Muscular canal for intercourse and childbirth.

External Genitalia and Mammary Glands

• Labia majora: Outer folds

• Labia minora: Inner folds

• Vestibule: Area between labia minora

• Clitoris: Erectile tissue

• Urethral orifice: Opening for urine

• Mons pubis: Fatty area over pubic bone

• Mammary glands: Produce milk

  • Areola: Pigmented area

  • Alveoli: Milk-producing units

  • Lactiferous ducts: Carry milk

  • Lactiferous sinus: Milk storage

Example: Digestive System Pathway

Food enters through the mouth, passes through the oropharynx and esophagus, is digested in the stomach, absorbed in the small intestine, and waste is expelled via the large intestine.

Example: Urinary System Flow

Blood is filtered in the kidneys, urine passes through the ureters to the bladder, and is expelled via the urethra.

Example: Reproductive System Structures

Sperm is produced in the testes, matures in the epididymis, travels through the vas deferens, and is expelled via the penis. Eggs are produced in the ovaries, travel through the uterine tubes, and may be fertilized in the ampulla.

Additional info: Academic context and definitions were added to expand brief lab review points into a comprehensive study guide.