Victor Forge
Muscles that resemble the shape of a feather with their fasciculi arranged like barbs along a common tendon are called pennate muscles. They are further classified as unipennate, bipennate, or multipennate depending on the number of angled sets of fibres attached to the central tendon. Smooth feather muscles, also known as mm. pennati, consist of bundles of smooth muscle cells attached to the feather follicles by short elastic tendons. An example of a unipennate muscle is the extensor digitorum in the forearm, while the rectus femoris located in the thigh is an example of a bipennate muscle. The deltoid muscle in the shoulder is an example of a multipennate muscle.
| Characteristics | Values |
|---|---|
| Definition | Muscles that have their fasciculi arranged like barbs of a feather along a common tendon |
| Other names | Pennate muscles |
| Muscle fibres | Approach a central tendon at an oblique angle |
| Types | Unipennate, Bipennate, Multipennate |
| Examples | Unipennate: Extensor digitorum in the forearm; Bipennate: Rectus femoris in the thigh; Multipennate: Deltoid muscle in the shoulder |
| Function | Capable of generating more tension, making them highly effective for activities requiring strength and power |
| Use | Often required to produce large forces to support or propel the weight of the body |
| Found in | Rock pigeons, domestic chickens, chicks |
Explore related products
What You'll Learn
Smooth feather muscles are found in birds
The smooth feather muscles are found in birds. These muscles are a part of the feather-bearing integument, which is an intricate, hydraulic skeleto-muscular apparatus of the feathers. Smooth feather muscles are a type of light, flat structure that grows from the skin of birds. They are usually a pair running from a feather follicle to each of the four surrounding follicles. Some of these muscles act to raise the feathers, while others depress them.
The smooth muscles in the skin include a series of minute feather muscles. The cardiac (heart) muscles and smooth muscles of the viscera of birds are similar to those of reptiles and mammals. The circulatory system of birds is more advanced than that of reptiles. There is a complete separation between pulmonary circulation (lungs) and systemic (body) circulation, as in mammals. Birds' hearts are large, ranging from 0.2 to over 2.4 percent of body weight.
Feathers provide effective insulation for birds. In addition, layers of subcutaneous fat add further insulation in penguins and some other water birds. Feathers, including down, trap body heat. The interlocking Velcro-like structure on many bird feathers creates a smooth, flexible, and resilient surface that supports flight and sheds water. As feathers grow, they mature into highly branched structures.
Birds are homeothermic (warm-blooded) and maintain a body temperature of approximately 41 °C (106 °F). This temperature may be slightly less during periods of sleep and slightly higher during intense activity. Heat loss through the feet in cold weather is minimised by reducing blood flow to the feet and by a heat-exchange network in the blood vessels of the upper leg.
Pelvic Floor Muscles: What's the Deal with Involuntary Action?
You may want to see also
Explore related products
Smooth feather muscles help coordinate a bird's wings
Birds are homeothermic, meaning they are warm-blooded and maintain a body temperature of around 41 °C (106 °F). Feathers, including down, provide effective insulation for birds. In addition, layers of subcutaneous fat add further insulation in penguins and some other water birds. Feathers also help birds regulate their body temperature by reducing blood flow to their feet in cold weather and dissipating excess heat through rapid panting.
The cardiac (heart) muscles and smooth muscles of the viscera of birds are similar to those of reptiles and mammals. Smooth feather muscles help coordinate a bird's wings. These muscles are a series of minute muscles, usually in pairs, running from a feather follicle to each of the four surrounding follicles. Some of these muscles raise the feathers, while others depress them.
The pectoralis major is the largest and most powerful muscle in a bird's body. It attaches to the keel of the sternum and is responsible for the downward stroke of the wings. The pectoralis major works with the supracoracoideus muscle, which is essential for the upward stroke of the wings. This muscle's pulley-like arrangement enables it to lift the wing by pulling on the tendon that passes over the shoulder joint.
The phalanges are essential for the articulation and spread of the primary feathers, enhancing the wing's surface area during flight. The primary feathers generate thrust, allowing birds to accelerate and maintain speed. Their asymmetrical shape helps create lift by manipulating airflow over the wing. The precise arrangement and overlap of primary feathers also contribute to reducing drag, enhancing aerodynamic efficiency.
Secondary feathers are found along the inner part of the wing, attached to the ulna. These feathers maintain lift and stability during flight. They are more symmetrical and shorter than primary feathers, providing a smooth surface that aids in sustaining altitude. They are crucial for gliding and soaring, as they help maintain a steady airflow over the wing.
Building Muscle: How to Increase Muscle Fibers
You may want to see also
Explore related products
Pennate muscles are named after their feather-like shape
The term "pennate" comes from the Latin "pinnatus" ("feathered, winged"), from pinna ("feather, wing"). Pennate muscles are named after their feather-like shape, with muscle fibres approaching a central tendon at an oblique angle, resembling the plumes of a feather attached to an elongated tendon. This structure maximises the muscle's force potential, allowing for a greater number of muscle fibres to be packed in parallel, increasing the muscle's ability to generate force.
There are three subtypes of pennate muscles: unipennate, bipennate, and multipennate. In a unipennate muscle, the fascicles are located on one side of the tendon, such as in the extensor digitorum of the forearm. A bipennate muscle, such as the rectus femurs, has fascicles on both sides of the tendon, similar to the arrangement of a single feather. Multipennate muscles have fascicles that insert on multiple tendons, converging towards a common tendon, like multiple feathers coming together at a central point. An example of a multipennate muscle is the deltoid muscle of the shoulder.
The pennation angle also plays a role in the function of pennate muscles. A larger pennation angle results in shorter muscle fibres, affecting the speed of muscle contraction. Additionally, the architectural gear ratio or anatomical gear ratio (AGR) of pennate muscles is defined by the ratio between the longitudinal strain of the muscle and muscle fibre strain or the ratio between muscle-shortening velocity and fibre-shortening velocity.
Overall, the unique structure of pennate muscles, resembling feathers, enables them to generate high amounts of tension and makes them well-suited for activities requiring strength and power.
Understanding Elevated Muscle Enzymes: What Do They Mean?
You may want to see also
Explore related products
Unipennate muscles have fascicles on one side of the tendon
The term "feather muscles" is not a recognised term, but pennate muscles seem to be what you are referring to. These are muscles where the fascicles are arranged along a tendon like the barb of a feather. The name comes from the Latin "penna", meaning feather.
Pennate muscles are flattened, and the tendon either extends along one side of the belly (unipennate), or it may course through the centre of the belly (bipennate). In the case of unipennate muscles, all the fascicles are on the same side of the tendon.
Unipennate muscles include the extensor digitorum in the forearm. The tendon may extend along one side of the belly, with the fascicles arranged on one side of the tendon. This is in contrast to bipennate muscles, where the fascicles are arranged on both sides of the tendon, such as in the rectus femoris muscle of the thigh.
The differing ways in which fascicles attach to tendons create a variety of skeletal muscle sizes and shapes. As pennation increases (from unipennate to multipennate), the muscle fibres become shorter, the number of fibres increases, and the cross-sectional area of the fibres increases. This design increases the muscle's ability to generate force, making pennate muscles particularly strong despite having a limited range of motion compared to parallel muscles.
Accessory Muscles: Understanding Their Unique Supportive Role
You may want to see also
Explore related products
Multipennate muscles have fibres that wrap around the tendon
The term "pennate" comes from the Latin "pinnatus" ("feathered, winged"), from pinna ("feather, wing"). Pennate muscles are those that have their fasciculi arranged like barbs of a feather along a common tendon. Due to this design, the muscle fibres in a pennate muscle can only pull at an angle, and as a result, contracting pennate muscles do not move their tendons very far.
Pennate muscles can be further subdivided into unipennate, bipennate, and multipennate. Unipennate muscles have fascicles located on one side of the tendon, such as the extensor digitorum in the forearm. Bipennate muscles have fascicles on both sides of the tendon, such as the rectus femoris in the thigh. Multipennate muscles have fibres that wrap around the tendon, like multiple feathers converging on a central point. An example of a multipennate muscle is the deltoid muscle in the shoulder.
The deltoid muscle covers the shoulder but has a single tendon that inserts on the deltoid tuberosity of the humerus. The fibres of the deltoid muscle branch out in multiple directions around the tendon. This arrangement allows for a greater number of muscle fibres to be packed into a smaller space, increasing the muscle's ability to generate force.
Multipennate muscles are capable of generating more tension, making them highly effective for activities requiring strength and power. However, their range of motion is limited compared to other muscle types.
The Bladder's Composition: All Muscle or More?
You may want to see also
Frequently asked questions
Feather muscles are smooth muscles that consist of bundles of muscle cells attached to the feather follicles of birds by short elastic tendons.
Some examples of feather muscles include the depressor feather muscles and the erector feather muscles.
Pennate muscles are a type of muscle that resembles the shape of a feather, with muscle fibres approaching a central tendon at an oblique angle.
Some examples of pennate muscles include the extensor digitorum in the forearm, the rectus femoris in the thigh, and the deltoid muscle in the shoulder.
There are three types of pennate muscles: unipennate, bipennate, and multipennate.
![Psoas Release Tool - 3-in-1 Massage Tool - Psoas Muscle Release Tool for Hip Hook, Flexor, Back, Glute, Iliacus, and Neck Pain Trigger Point and Myofascial Release Tool - Night Black [Patent Pending]](https://m.media-amazon.com/images/I/61tN6K63x1L._AC_UL320_.jpg)
