BIO Exam 2 Study Guide - Skeletal System and Anatomy

Vocabulary practice flashcards covering human skeletal system functions, bone anatomy, histology, development, physiology, cranial/facial/carpal identification, and articulations.

Hematopoiesis

Blood cell formation performed by red bone marrow.

Electrolyte balance (skeletal system)

The skeletal function of storing calcium and phosphate ions and releasing them into the blood as needed.

Acid-base balance (skeletal system)

The absorption and release of alkaline phosphate and carbonate salts by bone tissue to buffer blood pH.

Flat bones

Bones that function in protecting internal organs and providing attachment sites for muscles; examples include cranial bones, sternum, scapula, ribs, and hip bones.

Long bones

Bones that function in movement and leverage; examples include bones of the limbs, hands, and feet (such as the femur, humerus, metacarpals, and phalanges).

Short bones

Bones that provide stability and support while allowing some motion; examples include carpals and tarsals.

Irregular bones

Bones with complex shapes that protect internal organs and structures, such as vertebrae and certain skull bones.

Sesamoid bones

Bones formed within tendons to protect them from compressive forces, typically found in the feet, hands, and knees.

Patella

The sesamoid bone that is consistent in all individuals.

Osteogenic cell

A bone stem cell found in the periosteum and endosteum; the only bone cell capable of mitosis, which gives rise to osteoblasts.

Osteoblast

A bone-forming cell found in growing portions of bone (including periosteum and endosteum) that secretes organic osteoid matrix and aids in mineralization.

Osteocyte

A mature bone cell sitting in a lacuna that maintains bone tissue, communicates through canaliculi, and cannot undergo mitosis.

Osteoclast

A large, multinucleated bone-resorbing cell derived from monocyte/macrophage stem cell lineages that breaks down bone and releases minerals.

Osseous tissue

A calcified connective tissue consisting of approximately 1/3 organic matter and 2/3 inorganic matter.

Collagen (in bone)

An organic protein component of bone matrix that provides structural integrity, absorbs impact, and prevents bone breakage.

Hydroxyapatite

A crystallized calcium phosphate salt making up 85% of the inorganic bone matrix that imparts hardness to bone.

Spongy bone

A porous form of osseous tissue made of a 3D lattice of delicate struts called trabeculae, containing lacunae with osteocytes but lacking osteons, with spaces housing bone marrow.

Compact bone

Dense, calcified osseous tissue without visible spaces, organized into osteons that surround vertically oriented blood vessels to provide strength.

Diploë

The spongy bone layer located between two outer thin layers of compact bone in flat cranial bones.

Trabeculae

Thin struts of bone forming a 3D lattice in spongy bone, arranged along lines of stress to maximize strength while decreasing mass.

Diaphysis

The central shaft of a long bone consisting of a thick compact bone wall around the medullary cavity.

Epiphysis

The expanded end of a long bone filled with spongy bone containing red marrow, capped with articular cartilage.

Medullary cavity

The hollow center of the diaphysis lined by endosteum that contains yellow bone marrow in adults.

Epiphyseal plate

A plate of hyaline cartilage located between the epiphysis and diaphysis in children that serves as the growth zone for longitudinal bone extension.

Epiphyseal line

The remnant of the epiphyseal plate in adults formed around ages 18–21 when hyaline cartilage is completely replaced by osseous tissue.

Articular cartilage

Hyaline cartilage covering epiphyses at joints to reduce friction and absorb shock, persisting throughout adulthood.

Periosteum

A vascular, innervated fibrous membrane covering the outer surface of bone (except at articular surfaces) that anchors tendons and ligaments and houses osteogenic cells.

Endosteum

A reticular connective tissue membrane lining the medullary cavity, spongy bone trabeculae, and compact bone canals where bone growth, repair, and remodeling occur.

Nutrient foramen

A small opening in the diaphysis through which the nutrient artery and vein pass into and out of the bone.

Osteon

The basic structural unit of compact bone (also called a Haversian system), consisting of concentric lamellae surrounding a central canal.

Central canal

A longitudinal channel running through the center of an osteon containing blood vessels, nerves, and lymph vessels.

Perforating canal

A canal (also known as a Volkmann canal) branching at approximately 90 degrees from central canals to connect them to each other, the periosteum, and the endosteum.

Canaliculi

Tiny channels connecting adjacent lacunae that allow osteocytes to pass nutrients and communicate.

Red bone marrow

Hematopoietic tissue located throughout the skeleton in children, and restricted mainly to the axial skeleton, pelvic girdle, and proximal humerus and femur heads in adults.

Yellow bone marrow

Fatty, non-hematopoietic marrow found in the medullary cavity of adult long bones that can convert back into red bone marrow during severe anemia.

Ossification

The formation of bone tissue, occurring via intramembranous or endochondral mechanisms.

Mesenchyme

Embryonic connective tissue that serves as the precursor tissue for intramembranous ossification and chondroblast formation.

Osteoid tissue

A soft, uncalcified collagenous matrix secreted by osteoblasts prior to mineralization.

Intramembranous ossification

Bone formation directly from condensed embryonic mesenchyme, producing flat bones of the skull, facial bones, clavicle, and part of the mandible.

Endochondral ossification

Bone formation in which a pre-existing hyaline cartilage model is replaced by bone tissue, producing most bones of the skeleton.

Primary ossification center

The initial site of bone development during endochondral ossification, located in the center of the diaphysis.

Secondary ossification centers

Sites of bone replacement of cartilage located within the epiphyses, developing mostly after birth.

Appositional growth

Growth in bone diameter and thickness produced by osteoblasts in the periosteum depositing new bone tissue onto the outer surface.

Wolff's law of bone

The principle stating that bone architecture adapts and restructures itself according to the mechanical stresses applied to it.

Mineral deposition

The process by which osteoblasts extract calcium, phosphate, and other ions from blood plasma to form crystallized matrix in bone.

Mineral resorption

The process by which osteoclasts dissolve bone tissue to release stored minerals into the bloodstream.

Ectopic calcification

Abnormal mineral deposition and calcification occurring in soft non-skeletal tissues such as lungs, arteries, eyes, or muscles.

Arteriosclerosis

The hardening of the arteries, serving as a clinical example of ectopic calcification.

Hypocalcemia

An abnormally low concentration of calcium in the blood plasma.

Hypercalcemia

An abnormally high concentration of calcium in the blood plasma.

Sphenoid bone

A single butterfly- or wedge-shaped cranial bone at the middle base of the skull that touches all other cranial bones and contains the sella turcica.

Ethmoid bone

A single cranial bone situated between the eyes behind the nose, featuring the cribriform plate and perpendicular plate.

Mandible

The single lower jawbone holding lower teeth; the only movable bone of the skull at the temporomandibular joint (TMJ).

Nasal septum

A structure formed superiorly by the perpendicular plate of the ethmoid bone and inferiorly by the vomer, along with septal cartilage.

Scaphoid

The proximal lateral carpal bone on the thumb side that articulates with the radius; it is the most commonly fractured carpal bone.

Pisiform

A small pea-shaped carpal bone located on the anterior surface of the triquetrum in the proximal row.

Capitate

The largest carpal bone, located centrally in the distal row, which articulates with metacarpal III.

Hamate

A distal medial carpal bone possessing a prominent hook, articulating with metacarpals IV and V.

Hyoid bone

The unique bone in the body that does not articulate with any other bone.