Tiêu đề LOCOMOTION & MOVEMENT (SKELETAL SYSTEM).pdf ✅

 Digital www.allendigital.in [ 175 ] 1. Introduction : • Skeletal system consists of a framework of bones and a few cartilages. • This system has a significant role in movement shown by the body. • Imagine chewing food without jaw bones and walking around without the limb bones. • Bone and cartilage are specialised connective tissues. Bone Cartilage Very hard matrix. Slightly pliable matrix Calcium salts present. Chondroitin salts present Bone marrow is present that produces blood corpuscles. Such structure is absent. Growth in bone is bi-directional. Growth is cartilage is unidirectional. • In human beings, this system is made up of 206 bones and a few cartilages. It is grouped into two principal divisions – the axial and the appendicular skeleton. SWIMMING JUMPING WALKING RUNNING Human Skeletal System Bones-206 Cartilages Axial Skeleton Appendicular Skeleton Locomotion & Movement 04 (Skeletal System)
NEET : Biology [ 176 ] www.allendigital.in  Digital 2. Axial Skeleton : • Axial skeleton comprises 80 bones distributed along the main axis of the body. The skull, vertebral column, sternum and ribs constitute axial skeleton. (A) Skull : • The Skull is composed of two sets of bones – cranial and facial, that totals to 22 bones. Cranial Bones : Cranial bones are 8 in number (frontal-1, parietal-2, temporal-2, occipital-1, ethmoid-1 and sphenoid-1). Functions of cranial bones : They form the hard protective outer covering, cranium for the brain. Axial Skeleton (Number of bones-80) Distributed along the main axis of body Skull Skeleton Vertebral Column Sternum Ribs 26 in number 1 in number 24 in number Skull bones Associated Skull bones 22 in number 7 in number Sphenoid bone Ethmoid bone Frontal bone Parietal bone Temporal bone Occipital bone
Locomotion & Movement (Skeletal System)  Digital www.allendigital.in [ 177 ] Articulation of Skull With Vertebral Column : • The skull region articulates with the superior region of the vertebral column with the help of two occipital condyles (dicondylic skull). • Occipital bone consist of two projections called Occipital condyles therefore our skull is called dicondylic skull. • Cavity of sphenoid bone is called sella turcica in which pituitary gland is present. • At the base of skull an opening is present called foramen of magnum (Largest Foramen of Skull) through which spinal cord comes out. Facial Bones : • The facial region is made up of 14 skeletal elements (Inferior turbinals-2, Maxilla-2, Malar (Zygomatic)-2, Nasal-2, Palatine-2, Lacrimal-2, Vomer-1, Mandible-1) which form the front part of the skull. Occipital condyle Occipital bone pituitary gland in sella turcica Sphenoid Bone Lacrimal bone Nasal bone Zygomatic bone Maxilla Mandible Mandible is the only movable bone of skull Foramen of magnum Spinal cord
NEET : Biology [ 178 ] www.allendigital.in  Digital Hyoid Bone : • A single U-shaped bone called hyoid is present at the base of the buccal cavity and it is also included in the skull. • Hyoid bone is the only bone which is not attached with any other bone of the body. • Tongue is attached with hyoid bone. Ear Ossicles : • Each middle ear contains three tiny bones – Malleus, Incus and Stapes, collectively called Ear Ossicles. • Stapes is the smallest bone of our body. • The ear ossicles increase the efficiency of transmission of sound waves to the inner ear. Summary of skull bones and associated bones : SKULL SKELETON Skull Bones Associated Skull Bones Cranial-8 Facial-14 Hyoid bone-1 Ear ossicles-6 (Malleus, Incus, Stapes) Fronal-1 Parietal-2 Temporal-2 Occipital-1 Ethmoid-1 Sphenoid-1 Maxilla-2 Palatine-2 Zygomatic/Malar-2 Nasal-2 Lacrymal-2 Inferior nasal conchae/Turbinal bones-2 Mandible-1 Vomer-1 Lacrimal bone Nasal bone Zygomatic bone Maxilla Mandible Sphenoid bone Ethmoid bone Frontal bone Parietal bone Temporal bone Occipital bone Occipital condyle Hyoid bone Hyoid bone