Human Bones And Muscles

BONES OF HUMAN BODYI. SkullII. BackboneIII.RibsIV. LimbsV. GirdlesVI. Joints : a. Immovable ; b. Movable

Joints

SKELETON

Bony framework of the body.It includes the skull, vertebral column, collarbone, shoulder blades, rib cage, pelvic girdle and the bones of the hands, arms, feet, and legs. The skeleton supports the body and protects its internal organs. It is held together by ligaments and moved at the joints by the muscles, which are attached to it. The skeletal system includes both bones and cartilage.

SKULLSkeletal framework of the head.With the exception of the lower jaw, its bones meet in immovable joints (sutures) to form a unit that encloses and protects the brain and sense organs and gives shape to the face. The cranium, the upper part enclosing the brain, comprising the frontal, parietal, occipital, temporal, sphenoid, and ethmoid bones, is globular and relatively large compared to the facial portion. Its base has an opening through which the spinal cord connects to the brain. The skull sits on the top vertebra (atlas), which permits back-and-forth motion. For side-to-side motion, the atlas turns on the next vertebra (axis)

BACKBONEIn vertebrates, the body's major nerve tract.In humans it is about 18 in. (45 cm) long, running from the base of the brain through the vertebral column. It is covered by the meninges and cushioned by cerebrospinal fluid. It connects the peripheral nervous system (outside the brain and spinal cord) to the brain. The spinal cord and the brain constitute the central nervous system. Sensory impulses reach the brain via the spinal cord, and impulses from the brain travel down the spinal cord to motor neurons, which reach the body's muscles and glands via the peripheral nerves. The peripheral nerves are connected to the spinal cord via the spinal nerves. In humans there are 31 pairs of spinal nerves containing both sensory and motor fibres, which originate in the spinal cord and pass out between the vertebrae. These nerves branch and relay motor impulses to all parts of the body. Injury to the spinal cord may result in loss of communication between the brain and outlying parts and cause paralysis, loss of sensation, or weakness in the parts of the body served by areas below the injured region. Because nerve cells and fibres are unable to regenerate themselves, the effects are usually permanent.

RIBSThere are 12 pairs of ribs that form rib cage, attached to the backbone at the back. The first ten pairs of ribs are connected to the breast bone or sternum in the front. The last two pairs of ribe that are not joined to the sternum are called floating ribs.The rib cage protects the heart and lungs.

LIMBSA limb (from the Old English lim), or extremity, is a jointed, or prehensile (as octopus tentacles or new world monkey tails), appendage of the human or other animal body. In the human body, the upper and lower limbs are commonly called the arms and the legs.Human legs and feet are specialized for two-legged locomotion – most other mammals walk and run on all four limbs. Human arms are weaker, but very mobile allowing us to reach at a wide range of distances and angles, and end in specialized hands capable of grasping and fine manipulation of objects.

JOINTSStructure connecting two or more bones.Most joints, including synovial (fluid-containing) joints and those between vertebrae, which incorporate a disk, can move. Immovable joints include the sutures of the skull. Ligaments connect the bones of a joint, but muscles keep them in place. Joint disorders include various forms of arthritis, injuries (e.g., sprains, fractures, and dislocations), congenital disorders, and vitamin deficiencies.

TYPES OF JOINT1. Immovable joints: These joints do not

allow movement of bones, they simply connect bones. They found in the bones of the skull and pelvic.

2. Movable joints : These joints allow free movement of bones and are of four types.

-Hinge joint -Ball &Socket joint -Gliding Joint -Pivot Joint

Muscles

MUSCLESContractile tissue that produces motion for functions, including body

movements, digestion, focusing, circulation, and body warmth.It can be classified as striated, cardiac, and smooth or as phasic and tonic

(responding quickly or gradually to stimulation, respectively). Striated muscle, whose fibres appear striped under a microscope, is responsible for voluntary movement. Most of these muscles are phasic. They are attached to the skeleton and move the body by contracting in response to signals from the central nervous system; contraction is achieved by the sliding of thin filaments (of actin) between thick ones (of myosin); stretch receptors in the tissue provide feedback, allowing smooth motion and fine motor control. The branched fibres of cardiac muscle give it a netlike structure; contraction originates in the heart's muscle tissue itself with a signal from the natural pacemaker; vagus and sympathetic nerves control heart rate. Smooth muscle, the muscle of internal organs and blood vessels, is generally involuntary and tonic; its cells can operate either collectively or individually (in response to separate nerve endings) and have different shapes. Disorders of voluntary muscle cause weakening, atrophy, pain, and twitching. Some systemic diseases (e.g., dermatomyositis, polymyositis) can cause muscle inflammation.

Major muscles of the human body. (1) frontalis, (2) occipitalis, (3) temporalis, (4) orbicularis of eye, (5) nasalis, (6) orbicularis of mouth, (7) mentalis, (8) masseter, (9) platysma, (10) sternocleidomastoid, (11) trapezius, (12) pectoralis major, (13) deltoid, (14) latissimus dorsi, (15) anterior serratus, (16) external oblique, (17) rectus abdominis, (18) internal oblique, (19) infraspinatus, (20) teres minor, (21) teres major, (22) biceps, (23) triceps, (24) brachialis, (25) long radial extensor of wrist, (26) short palmaris, (27) pronator quadratus, (28) annular ligament of the carpus, (29) common extensor of digits, (30) ulnar extensor of wrist, (31) tendons of extensors of digits and wrists, (32) palmar aponeurosis, (33) gluteus medius, (34) tensor of the fascia lata, (35) rectus femoris, (36) pectineus, (37) sartorius, (38) long adductor of thigh, (39) gracilis, (40) vastus lateralis, (41) vastus medialis, (42) patella, (43) anterior tibialis, (44) medial head of gastrocnemius, (45) soleus, (46) annular ligament of ankle, (47) short extensor, (48) gluteus maximus, (49) biceps of thigh, (50) semitendinosus, (51) plantaris, (52) lateral head of gastrocnemius, (53) Achilles' tendon.

ABDOMINAL MUSCLEAny of the muscles of the front and side walls of the

abdominal cavity.Three flat layers—the external oblique, internal oblique,

and transverse abdominis muscles—extend from each side of the spine between the lower ribs and the hipbone. The abdominal muscles attach to aponeuroses, connective tissue sheaths that merge toward the midline, sheathing the rectus abdominis muscle on each side of the midline. The abdominal muscles support and protect the internal organs and take part in exhaling, coughing, urinating, defecating, childbirth, and motion of the trunk, groin, and lower limbs.

MUSCLE TUMOURAbnormal tissue growth in or originating from muscle

tissue.There are three major types. Leiomyomas are tumours of

smooth muscles, seen most often in the uterus but also in the digestive, urinary, and female genital systems. Part of the tumour may become malignant, but it usually does not spread or recur. Rhabdomyomas occur most often in cardiac muscle. Some forms spread, and it may remain contained in tissue or become diffuse and hard to remove. Rhabdomyomas involving both smooth and striated muscle are often malignant and may grow very large. The several types of rhabdomyosarcoma are rare; they arise in skeletal muscle, usually in the leg or arm, and are extremely malignant.

MUSCULAR DISEASE

Inherited disease that causes progressive weakness in the skeletal (and occasionally heart) muscle.

Muscle tissue degenerates and regenerates randomly and is replaced by scar tissue and fat. There is no specific treatment. Physical therapy, braces, and corrective surgery may help. Duchenne muscular dystrophy, the most common, strikes only males. Symptoms, including frequent falls and difficulty in standing up, start in boys 3–7 years old; muscle wasting progresses from the legs to the arms and then the diaphragm. Pulmonary infection or respiratory failure usually causes death before age 20. The gene can now be detected in female carriers and male fetuses. Becker dystrophy, also sex-linked, is less severe and begins later. Patients remain able to walk and usually survive into their 30s and 40s. Myotonic muscular dystrophy affects adults of both sexes, with myotonia and degeneration two to three years later, along with cataracts, baldness, and gonadal atrophy. Limb-girdle dystrophy affects the pelvic or shoulder muscles in both sexes. Facioscapulohumeral (face, shoulder-blade, and upper-arm) dystrophy starts in childhood or adolescence and affects both sexes; after initial symptoms of difficulty raising the arms, the legs and pelvic muscles can be affected; the main facial effect is difficulty in closing the eyes. Life expectancy is normal.

- MUSCULAR DYSTROPHY

THANK YOUName : MUKUL

Class : X ‘B’K.V.S sec-14 Gurgaon

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