EXERCISE - SNAKESSafi Afzal

Reema Shamoon - POJelena Radan – GLRobie Moughni Leika RaychouniCandace Babby 

MUSCULOSKELETALSYSTEM

Locomotion on Land

o Lateral Undulationo Sidewindingo Concertinao Rectilinearo Slide-Pushing

http://science.howstuffworks.com/environmental/life/zoology/reptiles-amphibians/snake3.htm

Safi

Modes of Locomotiono Lateral Undulation

• Most common• Waves of lateral

bending• Scales push off

resistance pointso Sidewinding

• Surfaces with few resistance points

• Diagonal path of travel

• Fastest mode of locomotion

http://www.cs.cmu.edu/~biorobotics/research/rsch_locomotion.htmlhttp://www.sciencephoto.com/media/414095/enlarge

Safi

Modes of Locomotion

o Concertina• Cycle of pulling and

straightening body• Static friction is

critical• Narrow passages

and climbingo Rectilinear

• Straight line• Large snakes• Belly scales

http://www.rubberbug.com/reptiles.htm

Safi

Modes of Locomotion

o Slide-Pushing• Large undulations• Snake tries to escape of smooth surface

and slips• Very irregular, small movements

http://www.wildernesscollege.com/snake-tracks.html

Safi

Locomotion in Watero All snakes can swimo Lateral undulationo Highly aquatic snakeso Semi-aquatic snakes

http://divehappy.com/indonesia/diving-gunung-api-volcano-of-the-sea-snakes/

Pattishal A.& Cundall D. (2008)

Safi

Locomotion in Air

o Genus Chrysopelea – “Flying snakes”

o Dorsovental flattening

o Lateral undulationo Generate lifto Glide ratio similar to

other gliders

http://animals.nationalgeographic.com/

animals/reptiles/flying-snake/

Safi

Snake Skeleton

o Composed of skull, vertebrae and ribs

o Atlas (first vertebra)

o Ribs all along body are NOT connected to breastbone

o Creates flexibility

o Ability to move in S and coil shapes.

http://www.blackdrago.com/science/anatomy_snake.htm

Reema

Belly Scales

o Line bottom of snake on its belly

o Creates agile mobility

o Work like a tire gripping/treading a surface

o Each belly scale is attached to a rib and muscle for optimal control over locomotion

http://ecx.images-amazon.com/images/I/41SwHhW%2BttL._AA300_.jpg

Reema

Hu et al.

o Robotic snakes tested in lateral undulatory movement with presence and absence of resistance points

o Weight distribution changes during movement is important

o Some snakes are able to lift their curves during lateral undulation• Loading (pressing down) and unloading

(lifting)• 35% increase in speed and 50% more energy

efficient

Reema

Hu et al. cont.In figure:-A depicts a lifting snake in action-B & C are frictional force distributions of nonlifting and lifting snake

- Green arrows magnitude and direction of force

- Red dots snake’s center of mass (also resistance point)

- Black dots inflection points

- Red lines place of lift

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2700932/?tool=pmcentrez

Reema

RESPIRATORY SYSTEM

http://bio4120w12.pbworks.com/f/1333385454/snake-anatomy.gif

Jelena

Lung Tissue

AIR SAC

(Madder, D)

Jelena

Air Flow in Snake Ventilation

(Clark , 1978)

Jelena

Terrestrial Snake Respiration

o Right Lung dominant – used respirationo Left Lung Vestigial

• Trachea• Bronchi • Lungs • Air sac

http://heat-pits.com.au/snake-anatomy-physiology/

Jelena

Aquatic Snake Respiration

o The nostrils have valves that consist of a specialized spongy tissue to keep water out

o Surface for Air

http://api.ning.com/files/lsNu6og-q1Iwofk1aQ9n*1melLZ-OT7gFqnSjOh2WWeiHsHZZGUDL2o4aW2V6AoQ043elbrZMJpZvOhTpdKK6dMFsSkxwa52/snake.jpg

Jelena

CARDIOVASCULAR SYSTEM

o Five Chambered Heart• Two Atria• One Ventricle

o Cavum pulmonale

o Cavum dorsal• Cavum

venousum• Cavum

arteriosum

(Moyes & Schulte, 2008)

Leika

Blood Circulation

o Heart acts as two-circuit pump:Systemic Right Atrium Cavum arteriosum Cavum venous Cavum pumonale Pulmonary Artery Left Atrium Systemic

http://mycelular.org/reptile/reptile-body-systems.htm

Leika

Cardiovascular System

o Ingest Large Preyo Lack Diaphragm• Pericardium-sac that encloses the heart.

http://arsanatomica.tumblr.com

Leika

Location of Heart Varies Depending on Ecological Niche

(Lillywhite, 1988)

Leika

Cardiovascular Shuntso Cardiac shunts within the heart

of the snake promote mixing of oxygen-depleted blood and oxygenated blood in different directions.  

o Pulmonary and Systemic Circulation

• Blood Pressure is the same in systole 

o Cardiac shunts occur because of incompletely divided ventricles  

o It also causes mixing of deoxygenated and oxygenated blood in ventricles.  

o Cardiac shunts direct blood away from its normal cycle.

Hicks and Wang, 2004Jensen et. al., 2010

Candace

Blood Flow Distribution

o Relative resistance of the systemic and pulmonary circuits regulates the blood flow distribution between the arteries.

 o Right-to-left Cardiac Shunt

• Blood that is recirculated within the systemic system • Caused by a higher pulmonary arterial resistance

(constriction)

 o Left-to-Right Cardiac Shunt

• Blood that is recirculated within the pulmonary system

• Caused by a reduced pulmonary vascular resistance (relaxation)

Jensen et. al., 2010

Candace

Washout Shuntso Python exhibits washou tshunts at the cavum

venosum• subdivided ventricle

• Cavum venosum very small

• Unable to exhibit other shunts due to the shape of the valve and its mechanisms  

o Bulbuslamelle and Muscular Ridge• Separation in early systole between cavum

pulmonale and cavum venosum

• Causes the residual venous blood in the cavum venosum and arterial blood in the cavum arteriosum to be washed out (from the shunt) into the aorta

• Low Residual volume and low cardiac output caused by the washout shunt 

Jensen et. al., 2010

Candace

Reduced Number of Shuntso The amount of mixing between the arterial and

venous blood is reduced in the python.

o Cardiac shunts are decreased in magnitude in comparison to other reptiles

o Indicated by the flow of blood which has the ability to remain separate during the cardiac cycle.

o Oxygen levels in arteries remain increased

• During digestion, the systemic venous oxygen concentrations are reduced.

o Pythons have the capability to produce high systemic blood pressure with low pulmonary blood pressure. Jensen et. al., 2010

Candace

ReferencesBartlett D, Mortola, J.P, Doll E.J. (1986). Respiratory mechanics and control of the ventilator cycle in the garter snake. Respiration Physiology. Volume 64, Pages 13-27. 

Bradshow, Chriss. (2007). Snake Anatomy & Physiology. Accessed 04.10.2012.  http://herptilesonline.com/The%20Internal%20Organ%20Systems%20(Major%20and%20Minor%20Organs).html  

 Clark, Brian, Gans, Carl, Rosenberg, H. (1978). Air flow in snake Ventilation. Biomedical Pres. Volume 32, Pages 207- 212.  

Graham, J. B. (1974). Aquatic respiration in the sea snake, Pelamis platurus. Respiration Physiology.  Volume 21, Page 17. 

Hu, David L. et al. (2009). The mechanics of slithering locomotion. PubMed. Proc Natl Acad Sci USA, 106(25): 10081-10085.  

Hicks, J. W., Wang, T. (2004, August 12). Hypometabolism in reptiles: behavioural and physiological mechanisms that reduce aerobic demands. Respiratory Physiology Neurobiology, (3), 261-271. 

Jensen, B., Nielsen, J. M., Axelsson, M., Pederson, M., Lofman, C., Wang, T. (2010, February). How the python heart separates pulmonary and systemic blood pressures and blood flows. The Journal of Experimental Biology, 213, 1611-1617. 

Life in its intricacy. (2011). Retrieved April 11, 2012, from http://arsanatomica.tumblr.com/page/2 

Lillywhite, Harvey. (1988). Snakes, Blood Circulation and Gravity. Scientific American. Pages 94-98. Madar, Douglas. Snake Anatomy. Accessed. 04.13.2012. http://mihalko-family.com/Documents/Snake%20Anatomy.pdf

 McCormick, K. (2010). Snake Anatomy. Dragon Science. http://www.blackdrago.com/science/anatomy_snake.htm  

Moyes, C. D., & Schulte, P. M. (2008). Principles of animal physiology. (2nd ed. ed.). San Francisco: Benjamin-Cummings Pub Co. Bunty. How Stuff Works: Snake. Accessed 04.13.2012. http://snakestypes.blogspot.ca/2008/12/grass-snake.html 

Perry Lacy. How Stuff Works. (2011). Snake Anatomy. Accessed 04.02.2012 http://science.howstuffworks.com/environmental/life/zoology/reptiles-amphibians/snake1.htm 

Ritter, Annalise. Chordata-Reptilia. (2012). Retrieved April 11, 2012 from http://sharon-taxonomy2009-p3.wikispaces.com/Chordata-Reptilia 

Shine R, Langkilde, Mason RT. (2003). Cryptic forcible insemination: male snakes exploit female physiology, anatomy, and behavior to obtain coercive matings. PubMed.  Volume 162, Issue 5, Pages 653-657. 

Tom Rachel. California Academy of Sciences. (2010). Flying Snake-2. Accesses 04.02.2012http://www.calacademy.org/blogs/rainforest/?m=201003 

Tom Rachel. California Academy of Sciences. (2010). Flying Snake-5. Accesses 04.02.2012http://www.calacademy.org/blogs/rainforest/?m=201003 

Moon, B. (2001). Snake locomotion. Retrieved from http://www.ucs.louisiana.edu/~brm2286/locomotn.htm 

Pattishall, A., & Cundall, D. (2007). Dynamic changes in body form during swimming in the water snake nerodia sipedon. Zoology, 111(1), 48-61.