How Animal Tissue Types Connect to Organ Systems

Epithelial tissue → Digestive System

• Columnar epithelium in intestine: villi + microvilli amplify surface area → maximum absorption.
• Goblet cells scattered throughout → mucus protects lining from digestive enzymes.
• Compound squamous in mouth/esophagus → protects against mechanical food abrasion.

Connective tissue → Musculoskeletal System

• Tendons (dense regular CT) bridge muscle and bone → force transmission.
• Ligaments (dense regular CT + elastin) stabilize joints → mobility without excessive movement.
• Bone (specialized CT) provides the rigid framework → support + protection + haematopoiesis.
• Cartilage (specialized CT) at joint surfaces → friction-free movement + shock absorption.

Muscular tissue → Circulatory System

• Cardiac muscle (involuntary + striated + autorhythmic) → continuous, synchronized pumping.
• Smooth muscle in vessel walls → regulates blood pressure and organ blood flow.

Neural tissue → Reflex Arc

• Sensory neurons (dendrites at receptor) → impulse toward CNS.
• Interneurons in CNS process signals.
• Motor neurons (axon to effector) → impulse away from CNS.
• Schwann cells (PNS) myelinate → fast saltatory conduction for rapid reflexes.

Connective tissue → Immune System

• Areolar CT contains macrophages (phagocytosis) and mast cells (inflammatory mediators).
• Blood (specialized CT) carries WBCs (lymphocytes, neutrophils) throughout body.
• Lymph (fluid CT) drains through lymph nodes for immune surveillance.