BMED 2206 - Biomechanics of Human Tissue and the Body

Vocabulary flashcards generated from the BMED 2206 lecture notes covering biomechanics, human anatomical structure, tissue mechanics, fracture, and viscoelasticity.

Organelles

Cytoplasmic structures, such as the nucleus and plasma membrane, that perform specific functions for cells within the structural hierarchy of the human body.

Tissues

Groups of similar cells that specialize to perform particular shared functions.

Organ Systems

Associations among multiple organs that work together to serve broad physiological functions.

Visceral Muscles

Involuntary muscles that twist and squeeze the digestive tract, constrict blood vessel walls to regulate blood pressure, and erect hairs in the skin.

Medial

An anatomical term referencing a position relatively close to the midline of the body or a movement towards the midline.

Proximal

An anatomical directional term indicating a position closer to a designated point of reference.

Ipsilateral

An anatomical term describing an activity, position, or landmark location situated on the same side as a reference point.

Newton's First Law

The law stating that a body at rest stays at rest, or a body in motion continues at constant velocity in a straight line, provided the net force acting on it is zero.

Kinematics

The branch of biomechanics that describes body movement in terms of position, velocity, and acceleration without considering the forces causing the motion.

Kinetics

The branch of biomechanics focusing on the causes of movement, specifically analyzing forces and torques.

Stance Phase

The phase of gait during which the foot remains in contact with the ground, comprising roughly $62\%$ of a normal walking cycle.

Swing Phase

The phase of gait during which the foot is lifted and moving through the air, accounting for about $38\%$ of a normal walking cycle.

Float Phase

A double limb unsupported period during running in which neither foot is touching the ground.

Biomechanics

An interdisciplinary field combining engineering mechanics with biology and physiology to study, design, and analyze living organisms and medical systems.

Statics

The branch of mechanics dealing with forces acting on rigid bodies that are in a state of mechanical equilibrium.

Rigid Body

An idealized solid body that undergoes zero mechanical deformation under the action of external forces.

Free-Body Diagram

A schematic representation of an isolated body or joint segment showing all external forces and moments acting upon it.

Engineering Stress

The applied load divided by the original cross-sectional area ($A$) of the material, calculated as tensile stress ($\sigma = \frac{F}{A}$) or shear stress ($\tau = \frac{F_s}{A}$).

Poisson's Ratio

The negative ratio of nominal lateral strain to nominal tensile strain ($\nu = -\frac{\epsilon_{\text{lateral}}}{\epsilon_{\text{tensile}}}$), approximately equal to $0.33$ for many materials.

Hooke's Law

The mechanical principle stating that stress is directly proportional to strain within the elastic range ($\sigma = E\epsilon_n$, $\tau = G\gamma$, $p = -K\Delta$).

Young's Modulus

The elastic modulus ($E$) given by the slope of a material's stress-strain curve in the linear elastic regime.

Tensile Strength

The maximum stress ($\sigma_{TS}$) achieved on an engineering stress-strain curve, signifying the onset of localized necking.

Ductile Fracture

A fracture mode characterized by significant plastic deformation and high energy absorption prior to structural failure.

Brittle Fracture

A fracture mode characterized by minimal plastic deformation and low energy absorption during crack propagation.

Stress Concentration Factor

The ratio ($K_t = \frac{\sigma_m}{\sigma_o} = 2\left(\frac{a}{\rho_t}\right)^{1/2}$) measuring the degree to which nominal stress is amplified at a crack tip or notch.

Griffith Theory of Brittle Fracture

An energy-balance formulation stating that crack propagation occurs when strain energy loss balances the surface energy required to create new crack faces.

Mode I Loading

The opening (or tensile) deformation mode where applied forces pull crack surfaces directly apart.

Stress Intensity Factor

A parameter ($K_I = Y \sigma \sqrt{\pi a}$) describing the magnitude of stress concentrations near the tip of a Mode I crack.

Viscoelasticity

A time-dependent material response exhibiting combined viscous (energy-dissipating) liquid behavior and elastic (energy-storing) solid behavior.

Osteoblasts

Bone-forming cells that originate from osteoprogenitor cells and synthesize new bone matrix.

Osteoclasts

Multinucleated cells derived from bone marrow myeloid stem cells responsible for bone matrix resorption.

Cortical Bone

The dense compact bone forming outer structural walls, organized into cylindrical osteons with concentric lamellae surrounding central Haversian canals.

Cancellous Bone

Spongy, trabecular bone composed of a porous network of osteocytes in matrix, capable of sustaining strains up to $50\%$ in vitro before yielding.

Anisotropy of Bone

The variation in mechanical properties (such as modulus and ultimate strength) of cortical bone depending on the directional angle of applied loading.

Wolff's Law

The principle of functional adaptation stating that bone alters its structure and mechanical properties to adapt to changing mechanical demands.

Tendon

A dense connective tissue with strictly parallel collagen fiber bundles designed to withstand high unidirectional tensile loads transmitted from muscle to bone.

Ligament

A dense connective tissue containing closely interlaced, nearly parallel collagen fibers that connects bone to bone to stabilize joints and direct motion.

Synovial Joint

A low-friction joint system featuring a fluid-filled cavity enclosed in a capsule, demonstrating low friction coefficients between $0.003$ and $0.024$ in human joints.