What is the difference between hydrostatic skeleton exoskeleton and endoskeleton

The clavicles are S-shaped bones that position the arms on the body. The clavicles lie horizontally across the front of the thorax chest just above the first rib. These bones are fairly fragile and are susceptible to fractures. For example, a fall with the arms outstretched causes the force to be transmitted to the clavicles, which can break if the force is excessive.

The clavicle articulates with the sternum and the scapula. The scapulae are flat, triangular bones that are located at the back of the pectoral girdle. They support the muscles crossing the shoulder joint. A ridge, called the spine, runs across the back of the scapula and can easily be felt through the skin Figure. The spine of the scapula is a good example of a bony protrusion that facilitates a broad area of attachment for muscles to bone.

The upper limb contains 30 bones in three regions: the arm shoulder to elbow , the forearm ulna and radius , and the wrist and hand Figure.

An articulation is any place at which two bones are joined. The humerus is the largest and longest bone of the upper limb and the only bone of the arm.

It articulates with the scapula at the shoulder and with the forearm at the elbow. The forearm extends from the elbow to the wrist and consists of two bones: the ulna and the radius.

The radius is located along the lateral thumb side of the forearm and articulates with the humerus at the elbow. The ulna is located on the medial aspect pinky-finger side of the forearm. It is longer than the radius. The ulna articulates with the humerus at the elbow. The radius and ulna also articulate with the carpal bones and with each other, which in vertebrates enables a variable degree of rotation of the carpus with respect to the long axis of the limb.

The hand includes the eight bones of the carpus wrist , the five bones of the metacarpus palm , and the 14 bones of the phalanges digits. Each digit consists of three phalanges, except for the thumb, when present, which has only two. The pelvic girdle attaches to the lower limbs of the axial skeleton. Because it is responsible for bearing the weight of the body and for locomotion, the pelvic girdle is securely attached to the axial skeleton by strong ligaments.

It also has deep sockets with robust ligaments to securely attach the femur to the body. The pelvic girdle is further strengthened by two large hip bones. In adults, the hip bones, or coxal bones , are formed by the fusion of three pairs of bones: the ilium, ischium, and pubis.

The pelvis joins together in the anterior of the body at a joint called the pubic symphysis and with the bones of the sacrum at the posterior of the body. The female pelvis is slightly different from the male pelvis. Over generations of evolution, females with a wider pubic angle and larger diameter pelvic canal reproduced more successfully.

Therefore, their offspring also had pelvic anatomy that enabled successful childbirth Figure. The lower limb consists of the thigh, the leg, and the foot. The bones of the lower limb are the femur thigh bone , patella kneecap , tibia and fibula bones of the leg , tarsals bones of the ankle , and metatarsals and phalanges bones of the foot Figure. The bones of the lower limbs are thicker and stronger than the bones of the upper limbs because of the need to support the entire weight of the body and the resulting forces from locomotion.

In addition to evolutionary fitness, the bones of an individual will respond to forces exerted upon them. The femur , or thighbone, is the longest, heaviest, and strongest bone in the body. The femur and pelvis form the hip joint at the proximal end. At the distal end, the femur, tibia, and patella form the knee joint. The patella , or kneecap, is a triangular bone that lies anterior to the knee joint.

The patella is embedded in the tendon of the femoral extensors quadriceps. It improves knee extension by reducing friction. The tibia , or shinbone, is a large bone of the leg that is located directly below the knee. The tibia articulates with the femur at its proximal end, with the fibula and the tarsal bones at its distal end. It is the second largest bone in the human body and is responsible for transmitting the weight of the body from the femur to the foot.

The fibula , or calf bone, parallels and articulates with the tibia. It does not articulate with the femur and does not bear weight. The fibula acts as a site for muscle attachment and forms the lateral part of the ankle joint. The tarsals are the seven bones of the ankle. The ankle transmits the weight of the body from the tibia and the fibula to the foot.

The metatarsals are the five bones of the foot. The phalanges are the 14 bones of the toes. Each toe consists of three phalanges, except for the big toe that has only two Figure. Evolution of Body Design for Locomotion on Land The transition of vertebrates onto land required a number of changes in body design, as movement on land presents a number of challenges for animals that are adapted to movement in water.

The buoyancy of water provides a certain amount of lift, and a common form of movement by fish is lateral undulations of the entire body. This back and forth movement pushes the body against the water, creating forward movement. In most fish, the muscles of paired fins attach to girdles within the body, allowing for some control of locomotion. As certain fish began moving onto land, they retained their lateral undulation form of locomotion anguilliform. The fibula acts as a site for muscle attachment and forms the lateral part of the ankle joint.

The tarsals are the seven bones of the ankle. The ankle transmits the weight of the body from the tibia and the fibula to the foot. The metatarsals are the five bones of the foot.

The phalanges are the 14 bones of the toes. Each toe consists of three phalanges, except for the big toe that has only two [link]. Evolution Connection Evolution of Body Design for Locomotion on Land The transition of vertebrates onto land required a number of changes in body design, as movement on land presents a number of challenges for animals that are adapted to movement in water.

The buoyancy of water provides a certain amount of lift, and a common form of movement by fish is lateral undulations of the entire body.

This back and forth movement pushes the body against the water, creating forward movement. In most fish, the muscles of paired fins attach to girdles within the body, allowing for some control of locomotion. As certain fish began moving onto land, they retained their lateral undulation form of locomotion anguilliform. However, instead of pushing against water, their fins or flippers became points of contact with the ground, around which they rotated their bodies.

The effect of gravity and the lack of buoyancy on land meant that body weight was suspended on the limbs, leading to increased strengthening and ossification of the limbs. The effect of gravity also required changes to the axial skeleton.

Lateral undulations of land animal vertebral columns cause torsional strain. In later tetrapods, the vertebrae began allowing for vertical motion rather than lateral flexion. Another change in the axial skeleton was the loss of a direct attachment between the pectoral girdle and the head.

This reduced the jarring to the head caused by the impact of the limbs on the ground. The vertebrae of the neck also evolved to allow movement of the head independently of the body.

The appendicular skeleton of land animals is also different from aquatic animals. The shoulders attach to the pectoral girdle through muscles and connective tissue, thus reducing the jarring of the skull. This type of motion requires large muscles to move the limbs toward the midline; it was almost like walking while doing push-ups, and it is not an efficient use of energy. Later tetrapods have their limbs placed under their bodies, so that each stride requires less force to move forward.

This resulted in decreased adductor muscle size and an increased range of motion of the scapulae. This also restricts movement primarily to one plane, creating forward motion rather than moving the limbs upward as well as forward. The femur and humerus were also rotated, so that the ends of the limbs and digits were pointed forward, in the direction of motion, rather than out to the side.

By placement underneath the body, limbs can swing forward like a pendulum to produce a stride that is more efficient for moving over land. The three types of skeleton designs are hydrostatic skeletons, exoskeletons, and endoskeletons.

A hydrostatic skeleton is formed by a fluid-filled compartment held under hydrostatic pressure; movement is created by the muscles producing pressure on the fluid. An exoskeleton is a hard external skeleton that protects the outer surface of an organism and enables movement through muscles attached on the inside. An endoskeleton is an internal skeleton composed of hard, mineralized tissue that also enables movement by attachment to muscles.

The human skeleton is an endoskeleton that is composed of the axial and appendicular skeleton. The axial skeleton is composed of the bones of the skull, ossicles of the ear, hyoid bone, vertebral column, and ribcage. The skull consists of eight cranial bones and 14 facial bones. Six bones make up the ossicles of the middle ear, while the hyoid bone is located in the neck under the mandible. The vertebral column contains 26 bones, and it surrounds and protects the spinal cord.

The thoracic cage consists of the sternum, ribs, thoracic vertebrae, and costal cartilages. The appendicular skeleton is made up of the limbs of the upper and lower limbs. The pectoral girdle is composed of the clavicles and the scapulae. The upper limb contains 30 bones in the arm, the forearm, and the hand.

The pelvic girdle attaches the lower limbs to the axial skeleton. The lower limb includes the bones of the thigh, the leg, and the foot. What are the major differences between the male pelvis and female pelvis that permit childbirth in females? The female pelvis is tilted forward and is wider, lighter, and shallower than the male pelvis. It is also has a pubic angle that is broader than the male pelvis. What are the major differences between the pelvic girdle and the pectoral girdle that allow the pelvic girdle to bear the weight of the body?

The pelvic girdle is securely attached to the body by strong ligaments, unlike the pectoral girdle, which is sparingly attached to the ribcage.

The sockets of the pelvic girdle are deep, allowing the femur to be more stable than the pectoral girdle, which has shallow sockets for the scapula. Most tetrapods have 75 percent of their weight on the front legs because the head and neck are so heavy; the advantage of the shoulder joint is more degrees of freedom in movement. Skip to content The Musculoskeletal System.

Learning Objectives By the end of this section, you will be able to: Discuss the different types of skeletal systems Explain the role of the human skeletal system Compare and contrast different skeletal systems. Most organisms have a mechanism to fix themselves in the substrate. Shortening the muscles then draws the posterior portion of the body forward. Although a hydrostatic skeleton is well-suited to invertebrate organisms such as earthworms and some aquatic organisms, it is not an efficient skeleton for terrestrial animals.

An exoskeleton is an external, hard, encasement on the surface of an organism. For example, the shells of crabs and insects are exoskeletons.

This skeleton type provides defense against predators, supports the body, and allows for movement through the contraction of attached muscles. As with vertebrates, muscles must cross a joint inside the exoskeleton. Shortening of the muscle changes the relationship of the two segments of the exoskeleton. Arthropods, such as crabs and lobsters, have exoskeletons that consist of 30—50 percent chitin, a polysaccharide derivative of glucose that is a strong-but-flexible material.

Chitin is secreted by the epidermal cells. A molted exoskeleton of a mantis is shown in figure 2. Figure 2: Molted Exoskeleton of a Mantis. Mollusks also possess an exoskeleton in the form of a hard, protective outer-covering. The exoskeleton of mollusks is made up of calcium compounds except for chitin.

Some reptiles such as turtles also possess a hard exoskeleton as mollusks. The exoskeleton of both mollusks and reptiles is not shed during growth. Endoskeleton: Exoskeleton refers to an internal skeleton such as the bony or cartilaginous skeleton of vertebrates. Exoskeleton: Exoskeleton refers to an external skeleton such as the chitinous skeleton in arthropods. Endoskeleton: Endoskeleton is made up of calcium and phosphorus.

Exoskeleton: Exoskeleton is made up of scales, chitinous cuticle or calcified shells. Endoskeleton: Endoskeleton present inside the body. Exoskeleton: Exoskeleton present outside the body.

Endoskeleton: Endoskeleton is found in vertebrates. Exoskeleton: Endoskeleton is found in arthropods. Endoskeleton: Endoskeleton is made up of bones and cartilages.

Exoskeleton: Exoskeleton is made up of chitin or calcium compounds.