Tessa Messing, Ben McClellan, Liam Gluck


Importance of Skeletal/Muscular System to Vertebrates:
The skeleton has three functions: support, protection and movement. Animals need skeletons to support them, to maintain their shape. Also, many animals have hard skeletons that protect soft tissues, an example being the vertebrate skull protecting the brain. Skeletons also aid in movement by giving muscles a firm structure to work against. There are three types of skeletons: hydrostatic, exoskeletons, and endoskeletons. In hydrostatic skeletons fluid is held under pressures and muscles control movement. An example of an animal with a hydrostatic skeleton is a flatworm. Also, most cnidarians have hydrostatic skeletons. The next skeleton, exoskeleton, is hard encasement deposited on the surface of an animal. Most mollusks have exoskeletons. Their shells are made up of calcium carbonate and act as a sheetlike extension of the body wall. As the mollusk grows, the shell is also enlarged. Clams and Mussels, examples of mollusks, have hinged shells which they close using muscles attached to the inside of the exoskeleton. The exoskeleton of an arthropod is a little different. It is a cuticle, a nonliving coat secreted by the epidermis. Muscles are attached to knobs and plates of the cuticle that extend into the body. About half of the cuticle is made up of chitin, and where extra protection is needed, the cuticle is hardened with organic compounds that cross-link the proteins of the exoskeleton. The last skeleton, endoskeleton, is made up of hard supporting elements such as bones, plates that are moved by muscles. Chordate skeletons are an example of endoskeleton and they can have joints connected by ligaments designed to have freedom of movement (we'll see this in Ms. Piggy!).

The Muscular System at the Cellular Level:
The muscular system at the cellular level is based on one of two basic contractile systems. Both these systems consume energy to move protein strands against one another. These two systems are known as microtubules and microfilaments. Microtubules are the structures responsible for the beating of cilia and the undulations of flagella. Microfilaments are the contractile elements of muscle cells and additionally they play a role in amoeboid movement. Although the contraction of muscles is very important, without a skeleton to work against, muscles alone cannot translate into the movement of an animal. The ability of animals to move parts of their bodies in different directions requires that muscles be attached to the skeleton in antagonistic pairs, meaning that each muscle is working against another.

*Amoeboid movement: the movement of an organism through the usage of a pseudopod at the front of the cell- digestive group*

Skeletal Muscle in General:
Vertebrate skeletal muscle is attached to the bones and is responsible for movement. A skeletal muscle is made up of a bundle of long fibers that extend the length of the muscles. Each fiber is a single cell with many nuclei and is itself a bundle of smaller myofibrils arranged longitudinally. These myofibrils are made up of two kinds of myofilaments, thin and thick. Thin filaments consist of two strands of actin and one strand of regulatory protein coiled around one another. Thick filaments are staggered arrays of myosin molecules. Skeletal muscles is considered striated because the arrangement of the repeating pattern of light and dark bands created by the myofilaments. The repeating units is known as a sarcomere, which is the basic unit of contraction of the muscle. The borders of the sacromere are known as the Z lines. These borders are lined up in adjacent myofibrils and when under a light microscope add to the striations visible. The are near the edge of the sarcomere is called the I band and the broad region that corresponds to the length of the thick filaments is the A band. The H zone is the center of teh A band that is made up of only thick filaments. This arrangement of thick and thin filaments in a skeletal muscle is extremely important because it is the key to how the muscle contracts.

Overview of Pig Muscular System
Hey Guys! I just wanted to let you in on some interesting facts about the piglet's muscular system. A fetal pig, in fact, has generally the same muscles as humans. The difference in size and location of these muscles between humans and pigs can be related to the fact that humans walk on two legs while the piggies walk with four! The hind legs of the piggies are exactly like the legs in the humans; the quadriceps, and the hamstrings are both present in the humans leg as well as the human! In case you were wondering there are three types of muscles in the pig. These three types are involuntary or smooth muscle, cardiac muscle, and voluntary or skeletal muscle, which is exactly like humans (except J-boi may have a few extra ones here and there) ! Involuntary or smooth muscles are usually found in the digestive and genital systems as well as blood vessel walls of the pig. The cardiac muscles are essentially what the heart is made of and of course it is involuntary. The voluntary or skeletal muscles are the muscles that are attached to a membrane called periosteum which is located on the bones. Also disease of the muscles in the pig is common. One common disease Porcine stress syndrome (PSS) is a recessive gene associated with prolonged muscle spasms which causes the failure of metabolism and the developing of acid conditions in the body, this condition sadly frequently ends in death.

*muscle cells are multinucleated due to their long length, an example of structure meets function- love digestive system crew

Muscular System Rap

Ayo ayo, so we roll up with our dissecting tools
me, goodluck, and tessa_vesicles ain't actin' like fools
we flips over the piggie ready to slice
my man goodluck askin' the pig if its willin' to pay the price
the pig said my man these whole dissection 'ish this be my vice

So i roll up actin all bad and mad and glad because we be tearing it apart
my homegirl tessa_vesicles holdin' piggy down tight, playin' her part
we look at the muscles, ready for a tussle
we open it up just to see two differte colors red and white
So i just said alright
and then we left
cause tessa had to go make a theft
on another pig's organ
as we said goodbye to JP Morgan

yo and about that test i think its on friday...
Ms. Krajewski, I also wrote the thing above the rap too...
but fo ril though I wrote the rap

Piglet Skeletal System Introduction
The skeleton of a pig, like the muscular system of the pig, is similar to the human skeleton. The pig, like the human, has different types of joints which allow great flexibility in movement. The ball-and-socket joint, where the humerus contacts the shoulder gridle and where the femur contacts the pelvic girdle, enables the pig to rotate his or her arms and legs and move them in several planes. The hinge joint, such as between the humerus and the ulna, restrict movement to a single plane of plane of up and down or side to side motion. Lastly, the pivot joint allows for circular rotation, such as in forearm at the elbow. Hopefully, we'll get some pics up soon of these joints and of the muscles Ben so fabulously described :)


I know its kinda hard to see from this picture, but this is the leg and the hip of the pig and the dark reddish brown ball you see that is partially hidden is Ms. Piggy's ball and socket joint! cool right? Surrounding the ball and socket joint are the pig's upper thigh/hip muscles, specifically the tensor fasciae latea, the sartorius, the vastius medialis, and probably the top of the adductor. The muscles around the ball and socket are extremely important to the function of the ball and socket joint. Although the ball and socket joint allows for a wide range of movement, such that the leg can swing in pretty much every direction, without the various leg muscles to support it, this type of movement wouldn't exist. This is yet another example of the co-dependency of the muscular and the skeletal system in the fetal pig. One cannot function without the other. If Ms.Piggy lacked one of these systems she wouldn't be able to run in the field or play in the mud... not that she ever could anyway :( She needs them both!


This is a zoomed out picture of the leg and the hip with the ball and socket joint. Now you can see the foot of the pig and how it is connected to the leg and the hip.

The Periosteum
Lo and behold, pigs have a muscle known as the periosteum, a protective layer that surrounds the spinal cord, and a muscle that is absent in humans. Infection of this thick tissue is common; the disease is known as periostisis and leaves areas of pig's spine vulnerable to injury or disalignment.

external image Fig1-9.gifhttp://www.thepigsite.com/pighealth/article/11/skeletal-system

*While it looks like the periosteum connects to the synovial membrane, the periostem actually loops behind in back before this membrane can touch it; luckily, periostisis is localized in individual bones and does not wreck the skeletal structure of entire appendages. The infection is still harmful though, because blood flow to this membrane (and thus the rest of the bones in the appendage) is severely inhibited; eventually, legs just shut down.

Periostisis is an infection of the muscle tissue of the periosteum, the thick, rigid tissue that circles the pig's bones. This infection occurs when young, developing bones are hurt by some outside force. A good example is when a baby hits its head really hard (so I guess that periosteum can be found in humans; my source that I used above is corrupt!) A more realistic worry, though, is one that livestock owners and puppy breaders have: if the mother gives birth on some hard surface, like the concrete on the garage or the hard-packed dirt in the barn, this nearly doubles the risk of periostisis in these animals.
Looking at the diagram of a pig bone that I copied, we can see that the periosteum wraps around most of the bone; infection of this tissue can lead to several vulnerable spots along the bone's area, therefore greatly increasing the risk that the pig breaks or dislocates a bone. Why this disease is so destructive, though, is that the periosteum protects blood vessels and nerves that are adjacent to the bone. Infection of the nerves causes a lot of pain for the piggies and doggies. Infection of the blood cells is worse, though.
Basically, all functions of the bone and surrounding ligaments, including maintenance of bone strength, bone growth, bone regrowth, and even sometimes muscle movement are severely inhibited, often completely. This means that the pigs are likely to live very painful days without being able to move their appendages, and will be losing blood to their bones by the hour. Sounds like a situation to pull the plug if you ask me, but I'm not that synacle. The pig just needs to ride out this tough stretch--just like humans do (periostisis of the tibia in humans is a severe case of what we know as shin splints!) Like humans, pigs benefit from certain stretches, ice and heat compressions, and mental relaxation. Ice, heat, and stretching helps recirculate blood flow in the damaged blood vessel, so processes can eventually return to normal. Mental relaxation is just being a friend for the piggy who needs one. And who wouldn't want to be this friend?

Further Pictures of the Muscular System


If you can't tell, this is the neck of the pig. The muscles towards the center of the image are the cleidomastoid, brachiocephalous, sternomastoid, and sternohyoid. As you can see, these muscles are whitish in appearance, making them soft, fast twitch, glycolytic muscles.


Hey so this is the periosteum!!!! You can see some bone matter towards the upper, clean cut edge of skin, and the more yellowey matter is the periosteum tissue. If you look at the spider-web looking white threads in the middle of the picture towards the right, this is the primary area of infection. Good thing this wasn't an issue for Miss Piggy; her primary tissue is completely intact.

Fast Twitch and Slow Twitch Muscles
While observing the varying colors in the muscles of the pig we began to wonder what the difference between the two was. Since there is a large similarity between the muscular system of humans and pigs I decided to delve into the categorization of the varying colors of muscles.

While dissecting the pig, my group noticed that the muscles were either a pasty white color or a reddish color. Each of these colors are attributed to a different type of muscle. The red muscles were a slow oxidative muscle, which is known as a slow twitch muscle that resists fatigue. These muscles contain a large amount of myoglobin, many mitochondria, and many blood capillaries. These muscles generate ATP by the aerobic system using oxygen. These muscles tend to split ATP at a low rate. These types of muscles are found in postural muscles are are needed for aerobic activities such as long distance running. The pasty white color muscles are known as fast glycolytic muscles which are also known as fast twitch muscles. These muscles have low amounts of myoglobin, few mitochondria, and low amounts of blood capillaries. However these muscles have large amounts of glycogen and are able to split ATP very quickly. The only problem is that these muscles fatigue easily. These fast twitch muscles are needed for sports that involve sprinting. All muscles include fast twitch and slow twitch muscle fibers however the amount vary depending on the purpose of the muscle.

To incorporate another sense, the tissues felt differently. The red muscles were quite fibrous and hard, while the white tissue was soft. These characteristics correlate to the fast-twich, slow-twich idea; the fast twitch muscles, not requiring as much oxygen, were nowhere near as absorbent and soft as the white muscles that do require a lot of oxygen. Also, since the pig uses the red muscle tissue for fast-twitch actions (muscle contractions) it would make sense that these muscles get more use, and are thus more more developed and strengthened. In terms of muscle proportions of a pig compared to those of a human, we noticed in class that the pig had a lot of muscle tissues surrounding its spinal chord.

The Frog

Frogs are famous for their ability to leap long distances. They leap from lilly pad to lilly pad with artistic ease. How are frogs such master leapers? Well, it just so happens that the frog's muscular system is developed in such a way as to ensure this ability. The leg muscles of the frogs work in antagonistic pairs. This means that as the cells of one muscle extends, the cells in the opposite muscle pair contract. An example of this is the Gastrocnemious and the Peroneus as shown below.


Also, because the hind limbs of the frog provide the main force in jumping, it makes sense that these muscles are particularly strong and efficient. The semimembranosus muscle, a large muscle connected between the frog's pelvis and a point just below the knee, pulls the upper part of the hind limb backward as it contracts (the leaping motion). What is unusual about this contraction is that it generates power throughout its range of contraction, not just at its beginning, which is uncommon for skeletal muscle in vertebrates.

It also should be noted that compared with their fish ancestors, frogs have a relatively strong skeleton. Their skeleton is designed for jumping, with their legs folded under the body. The pelvic girdle of the frog, which on each side is made up of three fused bones, the ilium, ischium and pubis, absorbs much of the impact of landing after the jump.



The Starfish


Perhaps the most recognizable structure on a starfish are its tubefeet: the structures that it uses to move along surfaces or attach itself to surfaces. This attachment mechanism is necessary for the starfish's protection. If Patrick from Spongebob didn't have tubefeet, he would be swept away from the shallow surface that is Bikini Bottom. He might even end up in Rock Bottom (remember that episode? I do hahahahahahahaaaa.) For lateral movements, the tube feet rotate from the trunk as though each individual foot were pedaling a bicycle. There is also a water-contraction system that propels the starfish vertically at speeds up to 30 centimeters per hour (flyin' !) My Lanclet is BiggerthanYours will discuss this movement further. he does this for his individual structure/function post, Mrs. K.

The Mussel

The mussel is a mollusk of the class Bivalvia, meaning that it has a shell (which is its exoskeleton) divided into two halves. The two parts of the mussel shell are hinged at the mid-dorsal line, giving the mussel its ability to open and close its shell. However, a mussel is only able to move its shell because of its powerful adductor muscle as shown in the image below.
external image mussel_2.jpg
The adductor muscle is also very important to the survival of the mollusk. Without it, the mollusk would be unable to protect its soft-bodied self because it would have no way to close its shell.

The Crawfish

external image crayfish.JPG

The crawfish is a particular kind of crustacean known as a decapod. It is characterized by its exoskeleton, or cuticle, which is made up of calcium carbonate. Calcium carbonate is what gives its exoskeleton its hardness. The portion of the cuticle that covers the dorsal side of the cephalothorax forms a shield called the carapace.

The Fish**



We looked up the muscular and skeletal systems in the fish. The tail and trunk muscles consist of a series of muscle block called myotomes that usually look like a curved W shape. They are separated by connective tissue called myosepta and the dorsal and ventral myotomes are separated by the horizontal septum. The jaw muscles have adductor muscles that close the jaw and abductor muscles that open the jaw. The fin muscles consist of abductor and adductor muscles that move the fins away from and close to the body and there are erector muscles that provide stability and flexibility in the fins. The skeleton in bony fish consists of bone and cartilage that are almost completely calcified. It provides structure, protection, and assists in leverage and red blood cell production. They have a vertebral column, cranium, jaw, ribs and intramuscular bones.
--Circulatory System Group

In the grasshopper, the exoskeleton is a cuticle, a non living coat secreted by the epidermis. Muscles are attached to the cuticle and 30-50% of the cuticle consists of chitin. This provides flexibility (Campbell 1046). [Reproductive/Excretory System].

In the earthworm, there is peristaltic locomotion. A hydrostatic skeleton, which is two sets of muscles and bristles, allows earthworm to crawl or burrow through moist ground. Contraction of longitudinal muscles thickens and shortens the worm while contraction of circular muscles constricts and elongates it (Campbell 1046). [Reproductive/ Excretory System]

Porifera, or sponges, are made up of a hollow tube with many pores. The skeleton is made up of lime or sillicon. Water is drawn through these pores, and that functions as the digestve system. The flow of water is propogated by moving flagella which line the surface of the chambers inside the porifera. A series of canals are connected to those chambers. Porocytes are the tubular cells that make up the pores. Pinacocytes form the outer epidermal layer of cells. Thsi is the closest form of true tissue. Myocytes are modified pinacocytes that control the pore openings and how much water can flow through them. The spiny points that stick out from the "skin" are called spicules. They are made of calcium carbonate or silica, which are used for structure and protection.

By: Marina and Lauren