Tube feet: Difference between revisions

Latest revision as of 14:23, 21 February 2025

Tube Feet[edit]

Tube feet are small, flexible, hollow appendages found in echinoderms, such as sea stars, sea urchins, and sea cucumbers. These structures are part of the water vascular system and play a crucial role in locomotion, feeding, and respiration.

Structure[edit]

Tube feet are typically composed of a bulbous upper section called the ampulla and a lower, tube-like section that extends outside the body. The ampulla is located inside the body cavity and is connected to the tube foot by a narrow canal. When the ampulla contracts, it forces water into the tube foot, causing it to extend.

The tube foot itself is often equipped with a sucker at the distal end, which allows the organism to adhere to surfaces. The walls of the tube feet are muscular and can contract to retract the foot or to create suction.

Function[edit]

Tube feet serve multiple functions in echinoderms:

Locomotion: By extending and retracting their tube feet, echinoderms can move across the substrate. The coordinated action of numerous tube feet allows for smooth and controlled movement.

Feeding: Tube feet can assist in capturing prey or in manipulating food items. For example, sea stars use their tube feet to pry open the shells of bivalves.

Respiration: Tube feet can facilitate gas exchange by increasing the surface area available for diffusion.

Sensation: Tube feet are sensitive to touch and chemical signals, aiding in environmental perception.

Types of Tube Feet[edit]

Different echinoderms have specialized tube feet adapted to their specific lifestyles:

Suckered tube feet: Found in many sea stars, these tube feet have a suction cup at the end, allowing for strong adhesion to surfaces.

Non-suckered tube feet: Found in some sea urchins, these tube feet lack a suction cup and are used more for sensory functions.

Pincer-like tube feet: Some species have tube feet that end in small pincers, used for cleaning the body surface.

Examples in Echinoderms[edit]

Sea Stars: Sea stars, such as the Pycnopodia helianthoides, use their tube feet for locomotion and feeding. They can extend their tube feet through small openings in their ambulacral grooves.

Sea Urchins: Sea urchins have tube feet that extend through their spines, aiding in movement and feeding.

Sea Cucumbers: These echinoderms use their tube feet primarily for locomotion and respiration.

Related Pages[edit]

Gallery[edit]

T. gratilla podia
Mithrodia clavigera
Pycnopodia helianthoides tube feet

@@ Line 1: / Line 1: @@
-{{Short description|Anatomical structures in echinoderms used for locomotion and feeding}}
+== Tube Feet ==
-'''Tube feet''' are small, flexible, hollow appendages found in [[echinoderms]], such as [[starfish]], [[sea urchins]], and [[sea cucumbers]]. These structures are part of the [[water vascular system]], a hydraulic system unique to echinoderms, and play a crucial role in locomotion, feeding, and respiration.
+[[File:Sea_urchin_Tube_feet_extended_past_the_Spines.jpg|thumb|right|Sea urchin tube feet extended past the spines]]
-==Structure==
+'''Tube feet''' are small, flexible, hollow appendages found in [[echinoderms]], such as [[sea stars]], [[sea urchins]], and [[sea cucumbers]]. These structures are part of the [[water vascular system]] and play a crucial role in locomotion, feeding, and respiration.
-Tube feet are typically elongated, cylindrical structures that extend from the [[ambulacral grooves]] on the oral surface of echinoderms. Each tube foot consists of an internal ampulla and an external podium. The ampulla is a bulbous structure located inside the body cavity, while the podium extends outside the body and is often equipped with a suction cup at its distal end.
-[[File:Starfish tube feet.jpg|thumb|right|Close-up of starfish tube feet showing the suction cups.]]
+== Structure ==
-The walls of the tube feet are composed of connective tissue and muscle fibers, allowing them to contract and extend. The inner surface is lined with cilia, which help in the movement of water within the tube foot.
+Tube feet are typically composed of a bulbous upper section called the [[ampulla]] and a lower, tube-like section that extends outside the body. The ampulla is located inside the body cavity and is connected to the tube foot by a narrow canal. When the ampulla contracts, it forces water into the tube foot, causing it to extend.
+[[File:Podia_de_Colobocentrotus_atratus.JPG|thumb|left|Podia of Colobocentrotus atratus]]
+The tube foot itself is often equipped with a sucker at the distal end, which allows the organism to adhere to surfaces. The walls of the tube feet are muscular and can contract to retract the foot or to create suction.
+== Function ==
-==Function==
 Tube feet serve multiple functions in echinoderms:
-===Locomotion===
+* '''Locomotion''': By extending and retracting their tube feet, echinoderms can move across the substrate. The coordinated action of numerous tube feet allows for smooth and controlled movement.
-Tube feet are primarily used for locomotion. By coordinating the extension and contraction of the tube feet, echinoderms can move across the substrate. The suction cups at the ends of the tube feet adhere to surfaces, allowing the organism to pull itself forward.
+* '''Feeding''': Tube feet can assist in capturing prey or in manipulating food items. For example, sea stars use their tube feet to pry open the shells of bivalves.
+* '''Respiration''': Tube feet can facilitate gas exchange by increasing the surface area available for diffusion.
+* '''Sensation''': Tube feet are sensitive to touch and chemical signals, aiding in environmental perception.
+== Types of Tube Feet ==
+[[File:Star_Fish_Tube_Feet.jpg|thumb|right|Starfish tube feet]]
+Different echinoderms have specialized tube feet adapted to their specific lifestyles:
+* '''Suckered tube feet''': Found in many sea stars, these tube feet have a suction cup at the end, allowing for strong adhesion to surfaces.
+* '''Non-suckered tube feet''': Found in some sea urchins, these tube feet lack a suction cup and are used more for sensory functions.
+* '''Pincer-like tube feet''': Some species have tube feet that end in small pincers, used for cleaning the body surface.
+== Examples in Echinoderms ==
-===Feeding===
+[[File:T._gratilla_podia.jpg|thumb|left|T. gratilla podia]]
-In addition to locomotion, tube feet are used in feeding. For example, starfish use their tube feet to pry open the shells of [[bivalves]] such as [[clams]] and [[mussels]]. Once the shell is opened, the starfish can evert its stomach to digest the prey externally.
-===Respiration===
+* '''Sea Stars''': Sea stars, such as the [[Pycnopodia helianthoides]], use their tube feet for locomotion and feeding. They can extend their tube feet through small openings in their [[ambulacral grooves]].
-Tube feet also play a role in respiration. The thin walls of the tube feet allow for gas exchange, facilitating the diffusion of oxygen into the body and the removal of carbon dioxide.
-==Water Vascular System==
+* '''Sea Urchins''': Sea urchins have tube feet that extend through their spines, aiding in movement and feeding.
-The water vascular system is a network of fluid-filled canals that facilitate the movement of tube feet. Water enters the system through the [[madreporite]], a sieve-like structure on the aboral surface. From there, water is channeled into the [[stone canal]], which leads to the [[ring canal]] surrounding the mouth. Radial canals extend from the ring canal into each arm, supplying water to the tube feet.
-The ampullae of the tube feet contract to force water into the podium, extending it. When the ampullae relax, water is drawn back, retracting the tube foot.
+* '''Sea Cucumbers''': These echinoderms use their tube feet primarily for locomotion and respiration.
-==Evolutionary Significance==
+== Related Pages ==
-The development of tube feet is a significant evolutionary adaptation that has allowed echinoderms to exploit a variety of ecological niches. Their ability to adhere to surfaces and manipulate objects has enabled them to become effective predators and scavengers in marine environments.
-==Related pages==
 * [[Echinoderm]]
 * [[Water vascular system]]
-* [[Starfish]]
+* [[Locomotion in echinoderms]]
-* [[Sea urchin]]
-* [[Sea cucumber]]
+[[File:Pycnopodia_helianthoides_on_glass.jpg|thumb|right|Pycnopodia helianthoides on glass]]
+== Gallery ==
+<gallery>
+File:T._gratilla_podia_(1).jpg|T. gratilla podia
+File:Mithrodia_clavigera_bras.jpg|Mithrodia clavigera
+File:Pycnopodiahelianthoides-tubefeet.jpg|Pycnopodia helianthoides tube feet
+</gallery>
 [[Category:Echinoderm anatomy]]
-[[Category:Locomotion]]