Grade 10 Life Sciences - Support Systems in Animals

Vocabulary flashcards covering Module 5: Support Systems in Animals from the Grade 10 Life Sciences syllabus, including types of animal skeletons, human axial and appendicular skeletons, long bone histology and gross anatomy, joint classifications, and skeletal disorders.

Hydrostatic Skeleton

A fluid-filled body cavity (coelom) surrounded by muscles under pressure, offering high flexibility and requiring minimal energy to build, but offering no protection and restricting the animal to moist environments.

Exoskeleton

A hard, external covering formed by chitin (a waxy, rigid protein) that provides protection against predators and desiccation, but restricts growth and requires periodic moulting.

Ecdysis (Moulting)

The periodic process by which an animal sheds its hard chitinous exoskeleton to accommodate growth.

Endoskeleton

An internal framework composed of rigid bone and flexible cartilage that grows with the animal and supports heavy body weights, though soft tissues remain exposed on the outside.

Axial Skeleton

The central axis of the human skeleton consisting of $80$ bones, comprising the skull, vertebral column, rib cage, and sternum.

Appendicular Skeleton

The division of the human skeleton consisting of $126$ bones, comprising the limbs and girdles (pectoral and pelvic girdles).

Foramen Magnum

The large opening in the base of the skull that encloses and permits the passage of the spinal cord.

Atlas (C1)

The first cervical vertebra of the neck region.

Axis (C2)

The second cervical vertebra of the neck region.

True Ribs

Rib pairs $1\text{--}7$ that attach directly to the sternum via costal cartilage.

False Ribs

Rib pairs $8\text{--}10$ that attach indirectly to the costal cartilage of rib $7$.

Floating Ribs

Rib pairs $11\text{--}12$ that remain unattached at their anterior ends.

Pectoral Girdle

The shoulder girdle that supports the upper limbs, consisting of the scapula (shoulder blade) and clavicle (collar bone).

Pelvic Girdle

The hip girdle that articulates with the sacrum, formed by the fusion of three bones: the ilium, ischium, and pubis.

Epiphysis

The expanded end of a long bone composed of spongy bone containing red bone marrow, covered by articular cartilage to reduce friction at joints.

Diaphysis

The long main shaft of a long bone composed of dense compact bone, enclosing the medullary cavity filled with yellow bone marrow.

Hematopoiesis

The production of red and white blood cells, which occurs within the red bone marrow of spongy bone.

Periosteum

A tough, fibrous vascular membrane surrounding the outside of the bone shaft, responsible for bone growth in thickness, protection, and repair.

Haversian Canal

A central longitudinal canal in an osteon containing blood vessels (supplying $O_2$ and nutrients) and nerve fibers.

Lamellae

Concentric rings of hard mineralized bone matrix composed of calcium phosphate and collagen fibers surrounding the Haversian canal.

Lacunae

Microscopic spaces arranged within lamellae that house living bone cells called osteocytes.

Canaliculi

Minute, radiating canals connecting lacunae to each other and to the Haversian canal, allowing the transport of nutrients and oxygen to osteocytes.

Immovable (Fibrous) Joint

A type of joint where bones are fused by fibrous tissue permitting no movement, exemplified by the sutures of the skull.

Slightly Movable (Cartilaginous) Joint

A type of joint where bones are joined by pads of cartilage permitting limited movement, such as intervertebral discs and the pubic symphysis.

Freely Movable (Synovial) Joint

A type of joint featuring a fluid-filled joint cavity that permits a wide range of movement, such as hinge and ball-and-socket joints.

Synovial Fluid

A lubricating fluid secreted by the synovial membrane that fills the joint cavity to allow smooth, frictionless movement.

Ligaments

Tough, elastic bands of connective tissue that hold bone to bone.

Tendons

Inelastic fibrous cords connecting muscle to bone to transmit pulling force.

Rickets

A condition in children characterized by weak, soft bones and bowed legs, caused by a severe deficiency of Vitamin D or calcium.

Osteoporosis

A skeletal disorder marked by progressive loss of bone density and mass, rendering bones porous, brittle, and easily fractured; common in post-menopausal women.

Osteoarthritis

A form of arthritis caused by the wear and tear of articular cartilage, leading to pain, swelling, and stiffness.

Rheumatoid Arthritis

An autoimmune disorder that causes joint destruction, joint inflammation, pain, and stiffness.