Movement and skeletal system

1. Movement and skeletal system

2. All organisms move to find food, escape from predators, migrate, protect their habitat. Plant movement is different than the other organisms because they anchor to soil with their roots. • Skeletal and muscular system help movement. • Skeleton gives shape to the organisms. • Exoskeleton covers the body of the organism(insects, molluscs) Endoskeleton is found inside of the body. (mammal, birds)

3. Support and movement in plants • Supportive tissues and turgor pressure give the main support to the body of the plants. • Turgor pressure is the pressure against cell wall of the plant cell. If Turgor pressure decreases the support will be less. • Supportive tissues (collenchyma-living, and sclerenchyma-nonliving) with thickened cell walls help plant body. • Also vascular tissues help support. • Plants move with nastic movements and tropisms as we mentioned before.

4. Skeletal (Support) system in Animals • In one celled organisms SiO2, CaCO3 fibrils help support. They move with cilia, flagella or by pseudopods. • Exoskeleton:Covers the body of the animal. Contains many organic (chitin- a polysaccharide) and inorganic molecules(CaCO3). Muscles are fixed to the inner surface of the exoskeleton. Exoskeleton prevents growth, so animals with exoskeleton should break up their skeleton and form a new skeleton for growth(molting). Also exoskeleton prevents water loss.

5. Hydrostatic exoskeleton- consists of a volume of fluid enclosed in a body cavity surrounded by muscle.of cnidarians, annelids, and many other soft-bodied invertebrates. • In Endoskeleton muscles are attached to them and with joints endoskeleton helps movement.

6. Human skeletal system • There are 206 bones in the human skeleton. It is less than the number of bones in the baby. The skeleton supports the body. The bones of the lower limbs support the entire body when we are standing, and the pelvic girdle supports the abdominal cavity. • The skeleton protects soft body parts. The bones of the skullprotect the brain; the rib cage protects the heart and lungs. • The skeleton produces blood cells. All bones in the fetus have red bone marrow that produces blood cells. In the adult, only certain bones produce blood cells. • The skeleton stores minerals and fat. All bones have a matrix that contains calcium phosphate, a source of calcium ions and phosphate ions in the blood. Fat is stored in yellow bone marrow. • The skeleton, along with the muscles, permits flexible bodymovement. While articulations (joints) occur between all the bones, we associate body movement in particular with the bones of the limbs.

7. Compact bone, or dense bone, contains many cylinder-shaped units called osteons. The osteocytes (bone cells) are in tiny chambers called lacunae that occur between concentric layers of matrix called lamellae. The matrix contains collagenous protein fibers and mineral deposits, primarily of calcium and phosphorus salts.In each osteon, the lamellae and lacunae surround a single central canal. Blood vessels and nerves from the periosteum enter the central canal. The osteocytes have extensions that extend into passageways called canaliculi, and thereby the osteocytes are connected to each other and to the central canal. • Spongy bone, or cancellous bone, contains numerous bony bars and plates, called trabeculae. Although lighter than compact bone, spongy bone is still designed for strength. Like braces used for support in buildings, the trabeculae of spongy bone follow lines of stress. In infants, red bone marrow, a specialized tissue that produces blood cells, is found in the cavities of most bones. In adults, red blood cell formation, called hematopoiesis, occurs in the spongy bone of the skull, ribs, sternum (breastbone), and vertebrae, and in the ends of the long bones.

8. Bone is made up of solidified extracellular matrix (osein)which contains protein, Ca, P, MgP, CaCO3,CaFl. • Bones are classified according to their shapes: • Long: arm, leg • Short: ankle • Flat: skull, • Irregular –vertebrae.

10. The skeleton is divided into the axial skeleton and the appendicular skeleton. The tissues of the axial and appendicular skeletons are bone (both compact and spongy), cartilage (hyaline, fibrocartilage, and elastic cartilage), and dense connective tissue, a type of fibrous connective tissue.

11. Joints: Bones are held together by joints. They are classified according to their ability to move. • Synovial joints: They can freely move . They have joint cavity which is filled with synovial fluid and covered with synovial membrane. Knee joint • Cartilaginous joints: Slightly moveable joints in vertebrae, ribs and pubic symphysis. They contain fibrous cartilage. • Fibrous joints: Immoveable joints in skull.

12. MUSCULAR SYSTEM • All invertebrates contain smooth muscle except arthropoda. • Arthropoda has skeletal(striated) muscle.

13. Human muscular system, structure of the muscle and contraction Smooth muscles are stimulated by autonomous nervous sytem. They contract with the help of the Ca ions and hormones. • Skeletal muscles contract with the information from brain and spinal cord. The junction between neuron axon ending with muscle is named as neuromuscular junction. One neuron can extend to many muscle fibers. • Muscles can contract with the stimulation of motor neurons. To start the contraction, the stimulus should be at a certain level. All or none law.

14. Stages of contraction • Stimulation of the muscle and start of contraction –latent period • Contraction- • Relaxation- muscle relaxes and waits for new stimulus. • http://www.brookscole.com/chemistry_d/templates/student_resources/shared_resources/animations/muscles/muscles.html

16. The plasma membrane of a muscle fiber is called the sarcolemma; the cytoplasm is the sarcoplasm; and the endoplasmic reticulum is the sarcoplasmic reticulum. • The sarcolemma forms T (transverse) tubules that penetrate into the cell so that they come into contact—but do not fuse—with expanded portions of the sarcoplasmic reticulum. • The expanded portions of the sarcoplasmic reticulum are calcium storage sites.

17. The sarcoplasm contains millions of myofibrils. Contractile portions of muscles. • Myofibrils and Sarcomeres • Myofibrils are cylindrical in shape and run the length of the muscle fiber. The striations of skeletal muscle fibers are formed by the placement of myofilaments within units of myofibrils called sarcomeres. A sarcomere extends between two dark lines called the Z lines. A sarcomere contains two types of protein myofilaments. The thick filaments are made up of a protein called myosin, and the thin filaments are made up of a protein called actin. Other proteins are also present. The I band is light colored because it contains only actin filaments attached to a Z line. The dark regions of the A band contain overlapping actin and myosin filaments, and its H zone has only myosin filaments. • The sarcoplasm also contains glycogen, which provides stored energy for muscle contraction, and the red pigment myoglobin, which binds oxygen until it is needed for muscle contraction.

18. Contraction mechanism • The muscle fiber contracts as the sarcomeres within the myofibrils shorten. • When a sarcomere shortens, the actin (thin) filaments slide on the myosin (thick) filaments and approach one another. • The movement of actin filaments in relation to myosin filaments is called the sliding filament theory of muscle contraction http://highered.mcgraw-hill.com/sites/0072324813/student_view0/chapter12/elearning_connection.html http://harveyproject.science.wayne.edu/development/muscle/juncti~1.htm

19. In the sarcomere, dark band (A) contains myosin and actin myofibrils. Light band contains (I) contains thin actin myofilaments. • When a sarcomere shortens, the actin (thin) filaments slide on the myosin (thick) filaments and approach one another. This causes the I band to shorten and the H zone to almost or completely disappear. • , the sarcomere shortens even though the filaments themselves remain the same length. • Myosin filaments break down ATP and have crossbridges that pull the actin filaments toward the center of the sarcomere.

21. Axon endings of a neuron contains a special neurotransmitter called acetylcholine. • When stimulus reaches the axon end, the neurotransmitter is released to the synaptic cleft. • Acetylcholine binds to receptors on muscle sarcolemma and forms a impulse in muscle fiber. • Impulse travels down T tubules in sarcolemma, and calcium is released from the sarcoplasmic reticulum. • Ca binds actin and on the actin myosin binding sites are free to bind with myosin. Myosin heads with ATP bind with actin myofilaments. Actin slides over the myosin by dephosphorylation of ATP. Sarcomere shortens. • Dark band (A band) stays at same length but Light band (I ) and H band shortens. • During relaxation, myosin detaches from the actin by ATP binding. And Ca ions are collected in Sarcoplasmic reticulum.

25. Muscle and bone relation • Muscles are attached to bones by tendons. • Antagonistic muscle pairs work opposite one another to bring about movement in opposite directions. For example, the biceps brachii and the triceps brachii are antagonists; one flexes the forearm, and the other extends the forearm