Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Concept Videos

Feces Formation and Defecation01:26

Feces Formation and Defecation

4.7K
After spending 3 to 10 hours in the large intestine, chyme loses a lot of water and becomes feces, the final product of digestion. Feces consist of undigested dietary fiber such as cellulose, mucus, sloughed-off epithelial cells, and microbes. The descending and sigmoid colon stores feces and uses haustral contractions to dry it out but retains enough water to give it a semi-solid texture.
The mass peristalsis then pushes the feces into the rectum, which stretches the rectal walls to activate...
4.7K
Design Example: Designing a Residential Plumbing System01:25

Design Example: Designing a Residential Plumbing System

1.2K
The design of residential plumbing systems requires carefully evaluating water demand, flow rates, and pressure dynamics to ensure both efficiency and reliability. The nature of water flow within pipes is defined by its Reynolds number, which classifies flow as either laminar (smooth) or turbulent.
1.2K
Physiology of the Gastrointestinal System III: Elimination01:26

Physiology of the Gastrointestinal System III: Elimination

1.7K
The gastrointestinal elimination process involves a complex interplay of neural and hormonal mechanisms that coordinate the final waste removal from the body. This intricate operation encompasses the absorption of water and electrolytes, vital for transforming the remaining indigestible food matter into feces. The large intestine is pivotal in water and electrolyte absorption, forming feces from unabsorbed minerals, undigested food, bacteria, bile pigments, and shed epithelial cells. Essential...
1.7K
Design Example: Flow Through a Fire Extinguisher01:12

Design Example: Flow Through a Fire Extinguisher

498
A fire extinguisher that uses pressurized water relies on fluid dynamics principles to generate a high-velocity stream capable of suppressing flames. The water is stored at a much higher pressure inside the extinguisher than the surrounding atmosphere. This pressure difference forces the water to flow rapidly when the extinguisher is activated, and the behavior of the water as it exits the nozzle can be understood using fundamental equations of fluid dynamics.
The key to understanding how the...
498
Hydrostatic Pressure Force on a Curved Surface01:04

Hydrostatic Pressure Force on a Curved Surface

2.6K
Hydrostatic pressure on curved surfaces is a fundamental concept in fluid mechanics with broad applications in the civil engineering field. When fluid is in contact with a curved surface, as in a reservoir, dam, or storage tank, it exerts pressure that varies in magnitude and direction along the curved surface. To assess the total hydrostatic force exerted by the fluid on a curved structure, engineers typically isolate the fluid volume adjacent to the surface and analyze the forces acting on...
2.6K
Major Losses in Pipes01:28

Major Losses in Pipes

2.1K
When a fluid flows through a pipe, it experiences energy losses due to frictional resistance along the pipe walls, known as major losses. These energy losses result in a pressure drop, which varies based on the flow conditions — whether laminar or turbulent — and the specific physical properties of the fluid and pipe.
Fluid flow can be classified as laminar or turbulent, primarily based on the Reynolds number. This dimensionless number reflects the relative influence of inertial to viscous...
2.1K

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by
Same author

The impact of environmental burden on surgical outcomes.

Surgery·2026
Same author

Bridging Science Across Species: A Biomechanics Outreach Event at the Zoo.

Integrative organismal biology (Oxford, England)·2026
Same author

Patient-Level Socioecological Comorbidities and Time to Initiation of Curative-Intent Treatment for Colorectal Cancer.

Diseases of the colon and rectum·2026
Same author

Meniscus Profiling of Fly Fishing Lures by Optical Diffraction.

Integrative and comparative biology·2026
Same author

Comparing the Readability and Usability of Patient Education Materials Generated by Different Large Language Models: ChatGPT, Copilot, and Gemini.

The Journal of surgical research·2026
Same author

Patient perspectives on access to bariatric surgical care in the Deep South: A qualitative study.

American journal of surgery·2026

Related Experiment Video

Updated: Mar 3, 2026

Visualizing Hyporheic Flow Through Bedforms Using Dye Experiments and Simulation
09:49

Visualizing Hyporheic Flow Through Bedforms Using Dye Experiments and Simulation

Published on: November 18, 2015

12.9K

Hydrodynamics of defecation.

Patricia J Yang1, Morgan LaMarca2, Candice Kaminski1

  • 1School of Mechanical Engineering, Georgia Institute of Technology, 801 Ferst Drive, MRDC 1308, Atlanta, GA 30332-0405, USA. hu@me.gatech.edu.

Soft Matter
|May 5, 2017
PubMed
Summary
This summary is machine-generated.

Mammal defecation occurs rapidly, regardless of animal size, due to a mucus layer facilitating fecal matter ejection. This study reveals insights into digestive physics and potential diagnostic applications.

More Related Videos

Investigating the Three-dimensional Flow Separation Induced by a Model Vocal Fold Polyp
09:58

Investigating the Three-dimensional Flow Separation Induced by a Model Vocal Fold Polyp

Published on: February 3, 2014

8.9K
An Analog Macroscopic Technique for Studying Molecular Hydrodynamic Processes in Dense Gases and Liquids
11:03

An Analog Macroscopic Technique for Studying Molecular Hydrodynamic Processes in Dense Gases and Liquids

Published on: December 4, 2017

9.1K

Related Experiment Videos

Last Updated: Mar 3, 2026

Visualizing Hyporheic Flow Through Bedforms Using Dye Experiments and Simulation
09:49

Visualizing Hyporheic Flow Through Bedforms Using Dye Experiments and Simulation

Published on: November 18, 2015

12.9K
Investigating the Three-dimensional Flow Separation Induced by a Model Vocal Fold Polyp
09:58

Investigating the Three-dimensional Flow Separation Induced by a Model Vocal Fold Polyp

Published on: February 3, 2014

8.9K
An Analog Macroscopic Technique for Studying Molecular Hydrodynamic Processes in Dense Gases and Liquids
11:03

An Analog Macroscopic Technique for Studying Molecular Hydrodynamic Processes in Dense Gases and Liquids

Published on: December 4, 2017

9.1K

Area of Science:

  • Gastroenterology
  • Biomechanics
  • Animal Physiology

Background:

  • Fecal characteristics vary widely among animals.
  • The physical mechanisms of defecation are poorly understood.
  • Defecation patterns are used in animal tracking and health diagnostics.

Purpose of the Study:

  • To investigate the physics of mammalian defecation.
  • To understand the relationship between animal size, large intestine dimensions, and defecation time.
  • To develop a mathematical model explaining defecation dynamics.

Main Methods:

  • Combined experimental and theoretical approaches.
  • Analysis of large intestine and fecal dimensions across species.
  • Videography, rheological measurements of feces and mucus.
  • Development of a mathematical defecation model.

Main Results:

  • Fecal length is approximately double the rectal length, indicating colon involvement in storage.
  • Defecation duration is remarkably consistent (12 ± 7 seconds) across mammals of varying sizes.
  • A mathematical model demonstrates mucus facilitating fecal sliding, akin to a sled on a chute.
  • Thicker mucus layers in larger animals aid in fecal ejection.

Conclusions:

  • The mucus layer is crucial for efficient defecation, explaining consistent defecation times.
  • The mathematical model accurately predicts defecation dynamics.
  • Defecation time may serve as a non-invasive diagnostic tool for digestive system ailments.