Chapter 7 Bones and Muscles

Transcription

1 Chapter 7 Bones and Muscles

2 Skeletal System - the framework of the human body there are 206 bones in our body

3 Functions of the skeletal system masterpiece of structure self repairing strength like concrete joints between bones to allow for movement movement is provided by muscles bones are able to produce blood cells a reservoir for minerals like calcium and phosphorus account for 20% of body weight

4 7.1 #1 Skeleton - consists of 2 broad divisions Axial Skeleton back bone of the skeletal system and is made up of 80 bones that are in the head and spine Appendicular Skeleton - consist of the bones of the extremities

5 7.1 #2 7.1 #3 Bones of the Head - 2 main parts cranium and facial bones Cranium Bones 1 - frontal bone, 2 - parietal bones, 2 - temporal bones, 1 - occipital bone Facial Bones mandible and maxilla these bones protect the brain,

6 7.1 #3 Fontanels - babies are bone with spaces between bones that allows for the skull to overlap to get through birth canal Within a year or two, these sutures close and seal around the suture lines

7 The most important facial bone is the maxilla bones, which attach to the mandible to form the mouth and is the only movable bone of the skull. These bones are held together by ligaments - connective tissue that holds bone to bones

8 Sinuses - bones of the skull designed with hollow spaces known as sinuses when you speak, sound waves resonate within these cavities 7.1 #3

9 7.1 #4 Hyoid and Middle Ear Bones Malleus, incus, and stapes are the smallest bones in our body U-shaped bone right above the (voice box) or larynx

10 7.1 #5 Bones of the Spine - Vertebrae, Sacrum, and Coccyx

11 7.1 #5 Cervical Curvatures Normal Curves Abnormal Curves

12 7.1 #6 Bones of the Chest - Thoracic Cage costal cartilage - flexible cartilage connecting sternum to vertebrae False ribs - don t connect to sternum Floating ribs - don t connect to thoracic region at all

13 7.2 #1 The Appendicular Skeleton - made up of 126 bones that form the: * pectoral girdle (shoulders) * pelvic girdle (hips) * appendages (arms and legs)

14 Bones of the Shoulders

15 7.2 #2 Bones of the Upper Extremities * forearm contains 2 bones - radius and ulna * 14 phalange bones attached to the metacarpals * the ulna doesn't rotate, but the radius can rotate on a moveable joint around the ulna

16 Bones of the Pelvis the pelvis is composed of 2 hip large, heavy hip bones attached to the sacrum of the skeleton

17 7.2 # 3 Bones of the lower Extremities * attached to metatarsals are 14 phalanges ligament - attaches bone to bone tendon - attaches bone to muscle * 26 moving bones in foot make it possible to carry body weight and be in motion at the same time

18 How Bones are Classified into 4 Categories Long Bones - support weight and help with motion (humerus, ulna and femur) Short Bones - are nearly as wide as they are long (metacarpals, metatarsals, and phalanges) Flat Bones - protect vital organs (ribs and cranial bones) Irregular Bones - any other bone (vertebrae for example)

19 Design of the Bone Long bones have on each end, 2 bulged hands connected by a long, straight shaft. These are the epiphysis and diaphysis The bone is covered with a layer of periosteum which contains blood vessels that helps supply it with nutrients

20 Strength of the bone * outer shell of bone made of dense, strong substance called compact bone * inside the epiphyses is a lightweight, porous tissue called spongy bone

21 Strength of Bone * inside the spongy bone is tiny open spaces for cells of red marrow - tissue that manufactures red blood cells and white blood cells for circulation and immunity In the cavity of the shaft is a tunnel running through the length of the bone called medullary cavity and holds red marrow in bones of infants and children and in adults, it is replaced with yellow marrow (fatty storage)

22 The hardness of the bone is due to microscopic crystals of a mineral substance called hydroxyapatite, which contains much calcium and phosphorus. Collagen is reinforced fibers that run between the crystals

23 Bone Health - vitamins needed Vitamin A, D, C, calcium, and phosphorus are necessary bone growth Vitamin D deficiency - rickets Vitamin A deficiency - retards bone development Vitamin C deficiency - abnormal slender and fragile bones

24 Exercise and Bones Osteoclasts - bone destroyers Osteoblasts - bone growers These determine which portions of bones undergo the most stress and strengthen each bone accordingly. If you expose your bones to stress, exercise, these will increase their activity and build additional bone to handle the extra strain. Then bones get bigger, denser, and stronger than those of non-athletes. If bones are not exercised, they lose strength and mass.

25 Fracture of a Bone - any break or crack in the bone Simple fracture - break in bone doesn't pierce the skin Compound fracture - break in bone pierces the skin

26 Bone Healing after Break Osteoclasts work at area and break down bone fragments and absorb them to make room for new construction. Osteoblasts replace area with spongy bone. These work together to clean out and rebuild bone.

27 Joints of the Skeleton - where bones join, or articulate

28 Problems of Joints arthritis - degenerative or inflammation of the joint

29 Problems of the Joints Sprain - occurs when the ligaments of a joint are overstressed, causing them to become tender and inflamed. Severe sprains can have bleeding inside the joint. Serious sprains can cause dislocation and a joint is overstressed and the bone can pop out of alignment. Ligaments are torn common in athletes requiring immobilization. Remember that ligaments hold bone to bone at the joint

30 Muscles

31 Skeletal Muscle over 600 muscles make up your body composed of cells known as muscle fibers these are bound together in parallel bundles has appearance of striated muscle designed to contract and relax very quickly

32 Smooth Muscle consists of shorter, wider cells in a looser arrangement designed for slow, powerful, and prolonged contractions in walls of blood vessels, squeezes food through digestive system, focus of lens in the eye and contracts to help during birth

33 Cardiac Muscle found only in the heart striated and similar to skeletal muscle, but designed to contract over and over without tiring

34 Movements of the Head and Face head- there are 2 sternocleidomastoid muscles that connect temporal bones of the skull to sternum and clavicles face - temporalis and masseter muscles and connect mandible to cranium and function to close jaw many smaller muscles help with smiles, expressions, and speaking, but work along with the above muscles

35 Movements of the Shoulders and Ribs most important is trapezius in shoulder that helps to tilt head and turn head intercostal muscles are small but very important in the chest wall to help you breathe assisting to expand and lift the rib cage to expand the thoracic cavity

36 Movements of Upper Arms pectoral muscles are the largest chest muscles from sternum to outer chest deltoid muscles form curve of shoulder and used to lift arms latissimus dorsi connect humerus to lumber area of spine and move arms to your rear

37 Movements of Lower Arms biceps brachii on front of arm allowing you to bend arm triceps brachii on the back of arms and allow you to twist forearm and rotate wrist

38 Movements of the Trunk or Torso rectus amdominis muscles extend from bottom of sternum to the front of the pelvic region and we use these to sit up or recline and to assist many other movements external oblique muscles connect the ribs to the pelvis and extend more to the sides these abdominal muscles are important for posture, giving birth, breathing, eating, eliminating water and to assist in heavy breathing during exercise erector spine muscles in the back assist the rink to allow to maintain straight back and holding your body up right

39 Movements of Upper Legs Gluteus maximus pulls your upper legs downward, away from the body and toward the rear. our buttocks we use these muscles when we jump, run or stand up they work with leg muscles to move legs

40 Muscles of the Lower Legs quadriceps femori are a trop of 4 muscles involved in moving lower legs and they are all connected to tibia by the patellar tendon (knee cap tendon) hamstring muscles are a group of 3 muscles in the back of each thigh and felt in the back of the knee sartorius muscle extends downward from front of the pelvic bone down thigh and to the tibia

41 Movements of the Feet gastrocnemius is the largest muscle of the calf and forms the bulge on the upper back part of the calf its main job is to extend the foot downward by pulling up on the heel via the Achilles tendon also helps the hamstrings bend the leg tibialis anterior muscle performs the opposite job of gastrocnemius, pulls foot up

42 Design of the Skeletal Muscle - composed of thousands of fascicles bound together by fascia and capillaries and nerves supply the muscle with fuel and oxygen and signal it to contract covered in a tough, translucent sheath called fascia (or epimysium) which binds the muscle together the muscle is made up of millions of individual muscle cells called muscle fibers each cell is encased in a sheath of tough connective tissue called endomysium which serves to strengthen the cell these cells are bundled together into larger groups called fascicles which hold several dozen endomysium-wrapped fibers bond together by connective tissue called perimysium

43 Design of the Skeletal Muscle - composed of thousands of fascicles bound together by fascia and capillaries and nerves supply the muscle with

44 Muscle Structure the contraction of muscles are found inside the long cylinders called myofibrils these extend the length of the muscle cell contain dozens or hundreds of myofibrils and fill the cell each myofibril is composed of millions of overlapping protein fibers arranged in repeating units called sarcomeres these sarcomeres give it the striated appearance

45 Nerve Impulses in Muscle muscle contractions are triggered by the nervous system by signals from motor neurons (nerve cell) where it connects to the muscle cell is called the neuromuscular junction the nerve triggers it to contract by releasing a special chemical called neurotransmitter at the junction the motor neuron and the group of muscle cells it controls is called motor unit

46 Power Plants of the Muscle all muscle cells contain different amounts of mitochondria power plants and a protein called myoglobin and store oxygen supplied by the blood for the function of the muscle muscles that contain large amounts of myoglobin are called red fibers (because of higher red blood cells) muscles that contain fewer amounts of myoglobin are called white fibers

47 Exercise for Healthy Muscles muscles that are exercised will enlarge and become stronger enlargement of muscles through use is called hypertrophy muscles can shrink also from lack of use and this is called atrophy they can shrink and eventually be replaced by connective tissue MUSCLES MUST BE USED