Lecture 5 The Skeletal System PDF

LECTURE 5 Skeletal system What are the functions of the Skeletal System? Support Locomotion Protection Storage Functions of Skeletal system Support it acts as an internal ‘scaffold’ upon which the body is built Locomotion it provides attachment for muscles, which op...

LECTURE 5 Skeletal system What are the functions of the Skeletal System? Support Locomotion Protection Storage Functions of Skeletal system Support it acts as an internal ‘scaffold’ upon which the body is built Locomotion it provides attachment for muscles, which operate a system of levers, i.e. the bones, to bring about movement Protection it protects the underlying soft parts of the body, e.g. the brain is encased in the protective bony cranium of the skull Storage it acts as a store for the essential minerals calcium and phosphate Haemopoiesis haemopoietic tissue forming the bone marrow manufactures the blood cells. How does it work? Bone Hard tissue that supports and protects other organs Cartilage Firm, flexible tissues that is not as hard as bone Ligaments Tissue that connects bone to bone Tendons Tissue that connects bone to muscle Joints Where bones meet and allows for movement Bones Spongy bone Fills ends of bones and lines hollow portions Red marrow Inside cavities of spongy bone, formation of red blood cells Yellow marrow Fat and energy storage Compact bone Layer of hard mineral matter, calcium, gives bones strength Periosteum Outer most layer, cushions the hard portion of the bone, repair of broken bones Joints  (Vertebrae/Back) Joints Plane Joints Ball&Socket Joint (Hip) Pivot Joint (Neck) Hinge Joint (Stifle) Properties of different synovial joint types Classification of Bones on the Basis of Shape  Bones can be categorized according to their shape: Long bones – these are typical of the limb bones, e.g. femur, humerus, and also include bones of the metacarpus/ metatarsus and phalanges; long bones have a shaft containing a medullary cavity filled with bone marrow Bones can be categorized according to their shape: Flat bones – these have an outer layer of compact bone with a layer of cancellous or spongy bone inside; there is no medullary cavity, e.g. flat bones of the skull, scapula and ribs Bones can be categorized according to their shape: Short bones – these have an outer layer of compact bone witha core of cancellous bone and no medullary cavity, e.g. carpal and tarsal bones Bones can be categorized according to their shape: Irregular bones – these have a similar structure to short bones but a less uniform shape; they lie in the midline and are unpaired, e.g. vertebrae. BONE SHAPES  Some specialized types of bone are: Sesamoid bones – these are sesame- seed-shaped bones that develop within a tendon (and occasionally a ligament) that runs over an underlying bony prominence; they serve to change the angle at which the tendon passes over the bone and thus reduce ‘wear and tear’, e.g. the patella associated with the stifle joint. Some specialized types of bone are: Pneumatic bones – these contain air filled spaces known as sinuses that have the effect of reducing the weight of the bone, e.g. maxillary and frontal bones Splanchnic bone – this is bone that develops in a soft organ and is unattached to the rest of the skeleton, e.g. the os penis (the bone within the penis of the dog and cat).  Human Skeleton  2 0 6 Bones  Axial skeleton: (80 bones) in skull, vertebrae, ribs, sternum, hyoid bone  Appendicular Skeleton: (126 bones)- upper & lower extremities plus two girdles  H a l f of bones in hands& feet AXIAL AND APPENDICULAR SKELETON AXIAL SKELETON  BONES OF THE SKULL 1. Cranial Bones 2. Facial Bones Facial Skeleton The facial skeleton is formed by the mandible, maxillae (r,l), zygomatics (r,l), and the bones that give shape to the nasal cavity: lacrimals (r,l), nasals (r,l), vomer, palatines (r,l), and the nasal conchae (r,l). Cranial Bones The eight cranial bones support and protect the brain: occipital bone, parietal bone (r,l), temporal bone (r,l), frontal bone, sphenoid, and ethmoid.  Skull sutures In fetuses and newborn infants, cranial bones are connected by flexible fibrous sutures, including large regions of fibrous membranes called fontanelles. The four major cranial sutures are: 1. LAMBDOID SUTURE (between the occipital and parietal bones) 2. CORONAL SUTURE (between the frontal and parietal bones) 3. SAGITTAL SUTURE (between the two parietal bones) 4. SQUAMOUS SUTURES (between the temporal and parietal bones)  Bones in Dog skull Lateral view of the dog skull showing main bony features Dog Mandible AXIAL SKELETON The Vertebral Column Cervical Vertebrae (7) Thoracic Vertebrae (12) Lumbar Vertberae (5) Sacrum Coccyx The vertebrae are divided into regions depending upon their position in the body: neck region; includes the atlas (first Cervical (C): vertebra) and axis (second vertebra) Thoracic (T): thoracic region Lumbar (L): lower back or abdominal region Sacral (S): croup or pelvic region Caudal (Cd) or coccygeal: in the tail VERTEBRAL COLUMN FOR SOME SPECIES Vertebrae of the cat Vertebrae of the cat Axial Skeleton The Thoracic Cage Sternum True Ribs (7) False Ribs (3) Floating Ribs (2) Bones in Human Thorax Appendicular Skeleton Thoracic Limb (Foreleg) Pelvic Limb (Rear Leg)  Axial Skelton Bassert Lab Manual, Page 120 APPENDICULAR SKELETON Thoracic Limb (Proximal to Distal) Scapula Humerus Radius Ulna Carpal bones (Carpus) Metacarpal Bones Phalanges UPPER LIMB APPENDICULAR SKELETON Bones in Human Hand and Foot Comparison of Anatomy of Bones of the thoracic limb  Pelvic Limb (Proximal to Distal) Connected to axial skeleton at sacroiliac joint Pelvis Femur Tibia Fibula Tarsal bones (tarsus) Metatarsal bones Phalanges  PELVIC GIRDLE The pelvic girdle is a ring of bones attached to the vertebral column that connects the bones of the lower limbs to the axial skeleton. Female and Male Pelvis Bones of the Lower Limbs FOOT AND ANKLE BONES FOOT ARCHES The arches of the foot are formed by the interlocking bones and ligaments of the foot. They serve as shock-absorbing structures that support body weight and distribute stress evenly during walking. FELINE AND CANINE WORD SKELETON CANINE SKELETON EQUINE SKELETON CHICKEN SKELETON REFERENCES: Aspinall, V., Cappello, M., & Phillips, C. (2015). Introduction to veterinary anatomy and physiology textbook. Elsevier. Cochran, Phillip E. (2011). Veterinary Anatomy and Physiology, A Clinical Laboratory Manual (2nd ed.). Cengage Learning. Reece, W. O. (2017). Functional anatomy and physiology of Domestic Animals. Wiley & Sons, Incorporated, John. END-STUDY WELL