The Musculoskeletal System

Transcription

1 The Musculoskeletal System Introduction The skeletal system and muscular system are often considered together because they are close in terms of structure and function. The two systems are referred to as the musculoskeletal system. They determine the basic shape of your body, support your other systems, and provide the means by which you move in the environment. Bones are the main organs of the skeletal system. They are primarily bone tissue. The places in the body where two or more bones are connected are called joints. The most common joints are the shoulder, elbow, wrist, hip, knee and ankle. Around the joints, bones are held together by straplike structures called ligaments. Ligaments are highly elastic and allow for movement. Bones have many functions. They protect internal organs for example, the skull protects the brain. They store minerals like calcium, produce blood cells within the bone marrow. Skeletal muscles are the main organs of the muscular system. Skeletal muscles are connected to bones by tendons. When a muscle contracts, then movement occurs. Also, when the body temperature drops below a certain level, skeletal muscles produce heat by shivering. Humans have three types of muscles that all function in movement. 1. Smooth muscle which lines the walls of the internal organs, and is involuntary, 2. Cardiac muscle which accounts for the beating of the heart and is also involuntary, and 3. Skeletal muscle which is the muscle attached to the skeleton and is responsible for movement of the human body. Skeletal muscle is voluntary.

2 Objectives After completing this exercise, you will be able to: 1. identify the major bones of the human skeleton, including the skull 2. describe the structure of a typical bone 3. identify slides and significant features of compact bone, spongy bone and hyaline cartilage 4. describe the structure of skeletal, smooth and cardiac muscle 5. demonstrate how muscles function

3 Identification of the Human Skeleton Bones Examine the human skeleton and with the help of the labeled chart, identify the following bones and label them in the figure on the following page. Bones of the Axial Skeleton. The axial skeleton comprises of the bones in the main vertical position. These include the skull, ribcage, sternum and vertebrae.

4 1. Skull The skull is composed of many small bones fused together. Note the following in the cranium. Observe the human skull and identify the following bones. a. Frontal Bone: forms the forehead b. Parietal bones: extends to the sides of the skull c. Occipital bone: curves to form base of skull d. Temporal bone: located on sides of skull e. Sphenoid bone: helps form base and sides of skull, and part of orbits 2. Note the facial bones: a. Mandible: the lower jaw b. Maxillae: the upper jaw and anterior portion of hard palate. c. Palatine bones: posterior portion of hard palate and floor of nasal cavity d. Zygomatic bones: cheek bones e. Nasal bones: form bridge of nose

5 Identify and label the bones. 3. The vertebral column provides support and protects the spinal cord. It is composed of 34 vertebrae separated from one another by intervertebral disks. The vertebral column is divided into 5 parts: a. seven cervical vertebrae: forming the neck region b. twelve thoracic vertebrae: where the ribs come together c. five lumbar vertebrae: in the abdominal region d. five fused sacral vertebrae called the sacrum e. four fused coccyx bones

6 4. The twelve pairs of ribs forms a case that supports the heart and lungs a. the ribs connect with the thoracic vertebrae and some are also attached to the sternum. Those ribs without any ventral attachment are called false ribs. 5. The sternum forms the breast bone and attaches to the ribcage.

7 The Appendicular Skeleton The appendicular skeleton includes all hanging bones and their supportive pectoral (shoulder) and pelvic (hip) girdles. Examine the skeleton and identify the following bones. Also, label your diagram with the appropriate bones.

8 1. pectoral girdle which supports the arms is composed of the a. clavicle: collar bones b. scapula: shoulder bones 2. The arm is composed of the following: a. Humerus: the large long bone of the upper portion of the limb. b. Radius: the long bone of the lower arm, c. Ulna: the other long bone of the lower arm d. Carpals: a group of small bones forming the wrist e. Metacarpals: slender bones forming the palm f. Phalanges: The bones of the fingers. 3. The pelvic girdle forms the basal support for the legs and is composed of two coxal bones (hip bones). The female pelvis is much broader and more shallow than that of the male 4. the leg is composed of a series of bones: a. Femur: the long bone of the thigh b. Tibia: the larger of the two long bones of the lower leg c. Fibula: the smaller of the two long bones of the lower leg d. Tarsals: A group of small bones forming the ankle e. Metatarsals: slender bones of the foot f. Phalanges: the bones of the toes

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10 Tissues of the long bone Compact bone is solid and dense and is found on the surface of the femur. Observe a prepared slide of compact bone and identify the following: 1. Osteons: also known as Haversian systems: Cylindrical structural units 2. Lamellae: concentric rings of matrix 3. Matrix: nonliving material maintained by osteocytes and osteoblasts (bone cells). Contains calcium. 4. Lacunae: cavities between the lamellae that contain the osteocytes and osteoblasts. 5. Central (Haversian) canal: canal in the center of each osteon 6. Canaliculi: Tiny tubules that allow nutrients to pass between the osteocytes.

11 Draw a picture of the slide: Examine a prepared slide of hyaline cartilage and identify the following: a. Lacunae: cavities in twos and threes scattered throughout the matrix, which contain chondrocytes or cells that produce cartilage b. Matrix: material that is more flexible than that of bone because it consist primarily of protein Draw a picture of the slide

12 The Muscular System Muscular tissue is composed of cells called muscle fibers. When muscle fibers contract, they shorten which gives them the ability to do work. Contraction of muscles allows for movement of body parts. Muscles contain the proteins actin and myosin. During contraction, actin filaments move past myosin filaments and units of the muscle called sarcomeres shorten. ATP is the energy source for muscle contraction. Examine a prepared slide of skeletal muscle. Skeletal muscle is attached to bone and is responsible for movement of the human body. The action is voluntary and controlled by the individual. How many nuclei do you see per cell? Draw a picture of the slide

13 Obtain a prepared slide of smooth muscle. Smooth muscle lines the walls of the internal organs and causes movement in the esophagus, stomach, and intestines. This action is involuntary and is not controlled by the individual. How many nuclei do you see per cell? Do you see any lines or cross striations like those observed in the skeletal muscle? Draw a picture of the slide

14 Obtain a prepared slide of cardiac muscle. Cardiac muscle is only found in the heart and controls the pumping action of the heart. The movement is involuntary. How many nuclei do you see per cell? Do you observe any lines or cross striations? Draw a picture of the slide

15 Questions: 1. Match the following bones to their locations in the human body Bone radius coxal bone ribs scapula fibula pectoral girdle leg axial skeleton arm pelvic girdle 2. What are the vertebrae in the neck region called? 3. Name the largest bone of the human body. 4. Complete the following table: Structure Type of muscle Voluntary or involuntary Mouth Esophagus Heart Stomach Biceps Small Intestine Legs Neck

16 Label the major bones.