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Relationship of Form and Function

Principle and Examples

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Relationship Principle

A direct relationship exists between the form (shape) of a human body part (molecule, cell, tissue, organ, or organ system) and its function. The relationship between the two features is often expressed as…

  • Form follows function: a body part can perform its function only if it is a certain shape or
  • Form determines function: the shape of a body part directly affects what it can do.

When this relationship principle is consistently applied to the study of anatomy and physiology, it helps make the material easier to understand.

Examples

Thumb Carpometacarpal Joint

Its Form

The thumb carpometacarpal joint is formed by the first metacarpal of the thumb and the trapezium carpal (wrist) bone. The articulating surface of each bone is saddle-shaped, meaning it is concave in one direction and convex in the perpendicular direction. The saddle-shaped articulating surfaces fit together at right angles and are complementary. One surface’s concavity matches the other’s convexity, and vice versa.

Its Function

This reciprocal concavo-convex relationship increases the thumb’s flexibility, including a motion called opposition. During this motion, the thumb moves forward (anteriorly) from the palm and sideways (medially) toward the tips of the other fingers, allowing the hand to grasp and manipulate objects.

Form

Form: the shape of the thumb carpometacarpal joint

Function

Function: thumb opposition.

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Hemoglobin Molecule

Its Form

Hemoglobin is a complex protein composed of four globular subunits. Each subunit contains a unique sequence of amino acids that determines its three-dimensional structure through folding. The specific amino acid sequence also influences how the subunits bond to form the complete hemoglobin molecule.

Its Function

The three-dimensional conformation of the hemoglobin molecule is essential for its primary function, which is to transport oxygen. This particular structure enables hemoglobin to bind with oxygen in the lungs and release it to the body’s tissues. In tissue cells, oxygen plays a crucial role in cellular respiration and the production of ATP (adenosine triphosphate), the energy-carrying molecule.

Form

Hemoglobin form: The sequence of amino acids controls the 3-D conformation of a hemoglobin molecule.

Function

Function:Hemoglobin function: the 3D conformation (shape) of a hemoglobin molecule determines its ability to bind with oxygen. thumb opposition.

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References and Attributions

OpenStax College, Anatomy and Physiology

Access for free at – https://openstax.org/books/anatomy-and-physiology/pages/1-introduction

Reference: “Overview of Anatomy and Physiology.”

LibreTexts

Access for free at – bio.libretexts.org

Reference 1: “Structure & Function – Proteins I.”

Reference 2: “Hemoglobin: Oxygen transport in mammals.”