Bones of the Appendicular skeleton: 4 bones in the shoulder girdle (clavicle and scapula each side) 6 bones in the arm and forearm (humerus,ulna and radius) 54 bones in the hands (carpals 16, metacarpals 10, phalanges 28) 2 pelvis bones 8 bones in the legs (femur, tibia, patella and fibula) 52 bones in the feet (tarsals 14, metatarsals10 , phalanges 28) Some books also mention 4sesamoid bones in hand and leg Bones of the Axial Skeleton The Axial Skeleton is the central core of the human body housing and protecting it’s vital organs. The axial skeleton consists of 80 bones: 29 bones in the head - (8 cranial and 14 facial bones) and then also 7 accociated bones (6 auditory ossicles and the Hyoid Bone) 25 bones of the thorax - (the sternum and 24 ribs) 26 bones in the vertebral column (24 vertebrae, the sacrum and the coccyx) Answer : (d)

The mandible, or jaw bone, is the only movable bone of the skull, forming the temporomandibular joint with the temporal bone. The lower teeth are rooted into the mandible while the upper teeth are rooted in the two maxillae. Answer : (c)

Each myosin (thick) filament is also a polymerised protein. Many monomeric proteins called Meromyosins constitute one thick filament. Each meromyosin has two important parts, a globular head with a short arm and a tail, the former being called the heavy meromyosin (HMM) and the latter, the light meromyosin (LMM). The HMM component, i.e.; the head and short arm projects outwards at regular distance and angle from each other from the surface of a polymerised myosin filament and is known as cross arm. The globular head is an active ATPase enzyme and has binding sites for ATP and active sites for actin. Answer : (a)

Acoelous vertebrae are flattened on both ends. Mammals are acoelous. Others ared concave hence option (a) correct Answer : (a)

Answer : (b)

Synovial joints are characterized by the presence of an articular cavity filled with synovial fluid surrounded by a joint capsule. In this type of joint, bones can perform larger movements, in part, because joint surfaces are coated with hyaline cartilage Answer : (c)

liver cells have the highest concentration of it - up to 8% of the fresh weight in well fed state, or 100-120 g in an adult. In the muscles, glycogen is found in a much lower concentration (1% of the muscle mass)muscles account for 20 percent to 30 percent of your total mass and therefore provide storage for a larger total amount of glycogen than the liver does Answer : (b)

A-band (for anisotropic) Each myofilament runs longitudinally with respect to the muscle fiber. There are two types: the thick bands and the thin bands. Thick bands are made of multiple molecules of a protein called myosin. The thin bands are made of multiple molecules of a protein called actin. Answer : (d)

The protein whose removal enables myosin to bind with actin in smooth muscle is Caldesmon. Caldesmon is believed to be an actin- regulatory protein, and binds with high affinity to actin or actin-tropomyosin. Caldesmon inhibits the activation by actin-tropomyosin of myosin MgATPase activity, and the inhibition can be reversed by Ca2+.calmodulin. Answer : (b)

The odontoid process (also dens or odontoid peg) is a protuberance (process or projection) of the Axis (second cervical vertebra). It exhibits a slight constriction or neck, where it joins the main body of the vertebra. Answer : (c)

1. troponin -binds to both actin and tropomyosin. -has binding site for Ca+2 needed for muscle contraction. -located at the junction of each successive pair of tropomyosin molecules. 2. myosin -contractile protein. -consists of two heavy (form tail region and two cross-bridges that bind with actin to produce force) and four light chains (that influence cross-bridge cycling kinetics and therefore sarcomere contraction velocity (option a correct) Remaining list of skeletal muscle protein is given at end of the answer Calcitonin is produced in humans primarily by the parafollicular cells of the thyroid, Thymosins are small proteins present in many animal tissues. (option b is wrong) Pepsin is an enzyme that breaks down proteins into smaller peptides (that is, a protease). It is produced in the stomach. Prolactin is produced by the pituitary gland in the brain. It's also known as PRL or lactogenic hormone. Prolactin is mainly used to help women produce milk after childbirth. (option c is wrong) Secretin is a peptide hormone produced in the S cells of the duodenum. Rhodopsin is a biological pigment found in the rods of the retina (option d is wrong) skeletal muscle proteins and their functions 1. actin -contractile protein -consists of 2 alpha helical strands of g-actin molecules bonded in series -each g-actin has a binding site where the s1 fragment of the myosin cross-bridge complex binds during muscle contraction 2. tropomyosin -two per actin filament -when muscle is relaxed, covers the myosin-head binding sites on the actin filament 3.titin -stabilizes the alignment of the thick filaments by connecting each myosin filament to both the z line and the m line -the titin that extends from the z line to the beginning of the myosin filament is believed to help keep the myosin filaments centered between the z lines -helps the sarcomere return to its resting length after the muscle has contracted or been stretched, contributing to the myofibril's elasticity and extensibility 4. nebulin-extends the length of each actin filament -believed to anchor the actin filament to the z-line and help regulate the length of the actin filament 5. desmin appears to stabilize the lateral and longitudinal alignment of adjacent sarcomeres, and therefore myofibrils 6. myomesin integral component of the m line that helps anchor the myosin filaments and the titin strands in the center of the sarcomere 7. alpha-actinin protein located within the z-line that attaches to both the actin filaments and the titin strands 8. dystrophin -provides stability to the cytoskeleton and sarcolemma of each muscle fiber-believed to help transmit the force generated by sarcomeres to tendons Answer : (a)

Answer : (d)

In each hind limb Femur =1 Tibia =1 Fibula =1 Patella = 1 Tarsals = 7 Metatarsals = 5 Phalanges = 14 Total =30 Answer : (c)

Three types of troponin a) Troponin C – Calcium bind to cause a conform change in Troponin I b) Troponin T – Binds to tropomyosin, forming a tropomyosin – troponin complex c) Troponin I – Inhibtory binds to actin, to hold the tropomyosin-troponin complexs in place Answer : (a)

Answer : (a)

Answer : (d)

Movement at costovertebral joints 7 to 10 about an anteroposterior axis results in raising and lowering the middle of the rib, the Bucket-handle movement. In elevation, this increases the transverse diameter of the thorax Answer : (c)

Answer : (b)

Two proteins (tropomyosin and troponin) work in concert with calcium to regulate muscle contraction. Answer : (c)

Rigor mortis is the medical term that is used to describe the hardening of body muscles after death. It's the result of the body's loss of adenosine triphosphate (or ATP), Answer : (a)

The ankle joint (or talocrural joint) is a synovial joint located in the lower limb. Functionally, it is a hinge type joint The knee is a modified hinge joint The elbow is a relatively simple hinge joint. But hinge joint is Synovial joint Answer : (d)

Answer : (a)

Answer : (b)

the atlas (C1) is the most superior (first) cervical vertebra of the spine. Answer : (b)

The biceps is attached to the scapula (shoulder blade) and the radius. The triceps is attached to the scapula, humerus and ulna. Answer : (d)

A sprain occurs when you overextend or tear a ligament while severely stressing a joint Answer : (c)

In skeletal and cardiac muscle, actin and myosin filaments are organized into sarcomeres that function as the fundamental unit of contraction. Smallest contractile unit of a muscle. The region of a myofibril between two successive Z discs. Answer : (a)

Joint between atlas and axis is pivot joint which is an example of synovial joint haracterised by the presence of a fluid filled synovial cavity between thearticulating surface of the two bones. Answer:(c)

Andrew Huxley and Niedergerke introduced it as a "very attractive" hypothesis. According to the sliding filament theory, the myosin (thick) filaments of muscle fibers slide past the actin (thin)filaments during muscle contraction, while the two groups of filaments remain at relatively constant length. Answer : (c)

The joints of the human body can be subdivided into "true" (discontinuous) and "false" (continuous) joints. True joints (Diarthrosis, synovial joints) True joints or Diathrosis have a discontinuity (interruption) between the bones that surround the joint. This space is known as joint space. It separates the articular surfaces, which are covered by articular cartilage. From the outside, the joint is surrounded by a tight joint capsule. It may have reinforcements at some places that are called articular or capsular ligaments. The joint capsule is made of two layers: an outer layer, the membrana fibrosa, made up of fibrous collagen Tissue. This layer runs into the Periosteum. an inner layer, the synovial membrane or inner layer of the joint, which is an epithelium like structure. The capsule of the joint defines an all-round enclosed cavity, the joint cavity, which is filled with a viscous fluid (synovia). Examples of true joints are: Upper ankle joint (talocrural joint) Lower ankle joint (talocalcaneonavicular joint) Knee joint (Articulatio genu) Shoulder joint (humeral joint) Hip joint (acetabulofemoral joint) False joints (Synarthrosis) False joints are continuous cartilage or connective tissue bone connections. They do not have any discontinuity (gaps) between them and therefore possess limited mobility. However, they are of high importance as growth zones for the body. These include: Cartilaginous joints (Synchondrosis, Articulatio cartilagineae) Synchondrosis: connected by hyaline cartilage, e.g. Sternum Symphysis: connected by fibrous cartilagel, e.g. intervertebral disc Fibrous joints (Articulationes fibrosa) Sutures: bone suture, e.g. between the bones of the skulls Syndesmosis: ligament-like, e.g. between Radius and Ulna Gomphosis: wedge-like, e.g. tooth in the alveole At the end of the growth process, the cartilage or connective tissue of “false” joints mature into complete bones. This is known as Synostosis Pathological joints (pseudarthroses) Pseudarthroses are a special form. They are no joints in the proper sense, but more or less mobile, pathological interruptions of the normal bone structure, which can occur in cases of insufficiently healing fractures. Answer : (a)