The physiology and mechanics of undulatory swimming: a student laboratory exercise using medicinal leeches

2009 ◽  
Vol 33 (3) ◽  
pp. 213-220 ◽  
Author(s):  
David J. Ellerby

The medicinal leech is a useful animal model for investigating undulatory swimming in the classroom. Unlike many swimming organisms, its swimming performance can be quantified without specialized equipment. A large blood meal alters swimming behavior in a way that can be used to generate a discussion of the hydrodynamics of swimming, muscle mechanics, hydrostatic skeletons, and the physiological features that allow leeches to deal with the volume increase and osmotic load imposed by the meal. Analyses can be carried out at a range of levels tailored to suit a particular class.

Soft Robotics ◽  
2017 ◽  
Vol 4 (3) ◽  
pp. 202-210 ◽  
Author(s):  
Ardian Jusufi ◽  
Daniel M. Vogt ◽  
Robert J. Wood ◽  
George V. Lauder

HortScience ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 900B-900
Author(s):  
E. Jay Holcomb ◽  
Robert Berghage ◽  
William Fonteno

The concepts of container water-holding capacity and air-filled porosity are important yet complicated for students interested in containerized crop production; however, both of these concepts can be observed and understood more completely if students develop a moisture retention curve. Our objectives were to describe an easy-to-construct and economical apparatus for creating a moisture retention curve and then to compare this curve with one generated by standard methods. The student method (column method) is constructed from plastic pipe cut into 5-cm sections. The sections of pipe are individually packed with a substrate then stacked and taped together, resulting in a 60-cm column of the substrate. The column is saturated and allowed to drain for 24 h. Then, the column is taken apart and the water content of each section determined gravimetrically. The water content of each section is graphed against height so that the result is a moisture retention curve. Data are presented to show the curve developed from the column method is similar to the curve developed by standard soil moisture tension method. The moisture retention curve can provide a better understanding of water and air holding capacities of substrates.


2013 ◽  
Vol 37 (1) ◽  
pp. 97-105 ◽  
Author(s):  
Glenn J. Tattersall ◽  
Suzanne Currie ◽  
Danielle M. LeBlanc

Gas exchange in animals is ultimately diffusion based, generally occurring across dedicated respiratory organs. In many aquatic amphibians, however, multiple modes of gas exchange exist, allowing for the partitioning of O2 uptake and CO2 excretion between respiratory organs with different efficiencies. For example, due to the physical properties of O2 being vastly different between air and water phases, the lung and skin play disproportionately important roles in O2 uptake. Many aquatic frogs are renowned for their cutaneous gas exchange capacity, where often the majority of CO2 is excreted across the skin. Furthermore, the roles of these gas exchange organs change with the animal's behavior. Under diving conditions, most of the frog's gas exchange needs must be met by the skin. In this article, we describe an interactive undergraduate laboratory that allows a class of students to share equipment while assessing pulmonary and cutaneous respiration in frogs provided with an air/water choice and under enforced dive conditions. Concepts explored in this laboratory exercise include animal energetics, diving reflex, pulmonary and cutaneous gas exchange processes, diffusion-based gas flux, and O2 debt.


2007 ◽  
Vol 31 (4) ◽  
pp. 352-357 ◽  
Author(s):  
P. Boily ◽  
B. B. Rees ◽  
L. A. C. Williamson

Here, we describe a laboratory experiment as part of an upper-level vertebrate physiology course for biology majors to investigate the physiological response of vertebrates to osmoregulatory challenges. The experiment involves measuring plasma osmolality and Na+-K+-ATPase activity in gill tissue of teleost fish acclimated to water of differing salinity. We describe results obtained using the widely available goldfish ( Carassius auratus) and a common baitfish, the Gulf killifish ( Fundulus grandis). The procedures described are generally applicable to other fish species, and they provide an alternative to the experimental use of humans or other mammalian species to investigate osmoregulation mechanisms. In addition to reenforcing the conceptual material covered in lecture, this laboratory exercise trains students in a wide range of laboratory and analytical skills, such as calculating and performing dilutions, pipetting, tissue sampling and homogenizing, preparing standard curves, conducting enzymatic assays, and analyzing and interpreting results. Typical student results are presented and discussed, as are common experimental and conceptual mistakes made by students.


2009 ◽  
Vol 33 (1) ◽  
pp. 72-77 ◽  
Author(s):  
B. B. Rees ◽  
P. Boily ◽  
L. A. C. Williamson

Anaerobic metabolism is recruited in vertebrates under conditions of intense exercise or lowered environmental oxygen availability (hypoxia), typically resulting in the accumulation of lactate in blood and tissues. Lactate will be cleared over time after the reoxygenation of tissues, eventually returning to control levels. Here, we present a laboratory exercise developed as part of an upper-level vertebrate physiology class that demonstrates the effects of exercise and hypoxia exposure on blood lactate in fish and the subsequent decrease in lactate during recovery. Typically, the results obtained by students demonstrate that both treatments cause significant increases in blood lactate concentrations (two to three times higher than control values) that decrease back to normal values within 3 h of recovery under normoxia. The procedures described are generally applicable to other fish species and provide an alternative to using humans or other mammalian species to investigate anaerobic metabolism.


Author(s):  
Ann S. Cooper ◽  
Bonnie Leksrisawat ◽  
Allison B. Gilberts ◽  
A. Joffre Mercier ◽  
Robin L. Cooper

2022 ◽  
Vol 8 ◽  
Author(s):  
Fabian Schwab ◽  
Fabian Wiesemüller ◽  
Claudio Mucignat ◽  
Yong-Lae Park ◽  
Ivan Lunati ◽  
...  

Due to the difficulty of manipulating muscle activation in live, freely swimming fish, a thorough examination of the body kinematics, propulsive performance, and muscle activity patterns in fish during undulatory swimming motion has not been conducted. We propose to use soft robotic model animals as experimental platforms to address biomechanics questions and acquire understanding into subcarangiform fish swimming behavior. We extend previous research on a bio-inspired soft robotic fish equipped with two pneumatic actuators and soft strain sensors to investigate swimming performance in undulation frequencies between 0.3 and 0.7 Hz and flow rates ranging from 0 to 20 cms in a recirculating flow tank. We demonstrate the potential of eutectic gallium–indium (eGaIn) sensors to measure the lateral deflection of a robotic fish in real time, a controller that is able to keep a constant undulatory amplitude in varying flow conditions, as well as using Particle Image Velocimetry (PIV) to characterizing swimming performance across a range of flow speeds and give a qualitative measurement of thrust force exerted by the physical platform without the need of externally attached force sensors. A detailed wake structure was then analyzed with Dynamic Mode Decomposition (DMD) to highlight different wave modes present in the robot’s swimming motion and provide insights into the efficiency of the robotic swimmer. In the future, we anticipate 3D-PIV with DMD serving as a global framework for comparing the performance of diverse bio-inspired swimming robots against a variety of swimming animals.


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