Principles of Human Body Systems: Unit 1

Comprehensive vocabulary flashcards covering anatomical terminology, body planes, tissue types, the skeletal and muscular systems, synovial joints, muscle contraction mechanisms, and bone fracture mechanics based on Unit 1 notes.

Human Body Systems

The $11$ organized networks of organs and tissues in the human body: integumentary, skeletal, muscular, lymphatic, respiratory, digestive, endocrine, cardiovascular, urinary, reproductive, and nervous systems.

Fibrous join

A fixed or immovable joint that connects bones. It is made primarily of collagen.

Cartilaginous joint

A joint that has some motion to it with hyaline cartilage present in the space between articulating bone

Synovial joint

A moveable joint that contains synovial fluid in the space around it to reduce friction the most common type of join in the body

Synovial fluid

Lubricant that fills space and formed through filtration through capillaries.

Particular capsule

Strengthen the joint

Bursae

flattened sacs that contain synovial fluid, reduced friction

Hinge joints

Cylindrical projections fit into concave shapes on the articulating bone

Saddle

Has both concave and coved surfaces that allow for more movement than condoled joints like the thumb join

Axial Skeleton

The portion of the skeleton located on or near the central vertical axis of the body, including the head, neck, and trunk.

Appendicular Skeleton

The portion of the skeleton that supports the limbs and connects them to the torso.

Coronal Plane

A vertical body plane running side to side that divides the body into anterior (front) and posterior (back) sections.

Sagittal Plane

A vertical body plane that divides the body or an organ into unequal right and left portions.

Median Plane

A specific vertical plane that divides the body directly down the middle into equal left and right portions.

Transverse Plane

A horizontal body plane that divides the body into superior (upper) and inferior (lower) sections.

Oblique Plane

A diagonal body plane that cuts at an angle other than the three standard anatomical planes.

Pelvic Girdle Sexual Dimorphism

Distinct anatomical differences between biological sexes where the female pelvis is wider and shallower, and the male pelvis is narrower, deeper, and has a pointier bottom.

Epithelium

Tissue that forms the linings, coverings, and glandular tissue of the body, characterized by cells packed together tightly in continuous sheets.

Connective Tissue

Tissue that protects, supports, and binds together other body tissues, made up of various cell types embedded in varying amounts of nonliving extracellular substance (e.g., bone, cartilage, adipose tissue, and blood).

Adipose Tissue

A tightly packed and highly vascularized connective tissue found in body fat that helps store nutrients, protect organs, and insulate the body.

Bone Tissue

A very rigid connective tissue containing collagen fibers and calcium salts, specialized to support and protect body tissues within the skeleton.

Muscle Tissue

Tissue specialized to contract and cause movement; occurs in three main types: skeletal, cardiac, and smooth.

Nervous Tissue

Tissue composed of specialized cells called neurons along with supporting cells; receives and sends electrical signals, responds to stimuli, and transmits impulses throughout the brain, spinal cord, and nerves.

Directional Terms

Words that describe the location of one anatomical structure in relation to another, or indicate specific locations on organs and bones.

Body Cavities

Enclosed spaces within the body that house and protect internal organs or viscera; the two main cavities are the dorsal and ventral cavities.

Thoracic Cavity

The chest cavity located within the ventral cavity superior to the diaphragm.

Superior (Cranial)

Directional term indicating a structure located above another structure or closer to the head.

Inferior

Directional term indicating a structure located lower or further down toward the feet.

Anterior (Ventral)

Directional term referring to the front side of the body or further toward the front.

Posterior (Dorsal)

Directional term referring to the back side of the body or further toward the back.

Medial

Directional term indicating a position closer toward the midline of the body.

Lateral

Directional term indicating a position away from the midline, toward the side of the body.

Proximal

Directional term denoting a position closer to the trunk or point of attachment of a limb.

Distal

Directional term denoting a position farther away from the trunk or point of attachment of a limb.

Superficial

Directional term meaning located closer to the exterior surface of the body.

Deep

Directional term meaning located further inward from the surface of the body.

Prone

Anatomical orientation in which the body is lying face down.

Supine

Anatomical orientation in which the body is lying face up.

Orbicularis Oculi

A circular facial muscle located directly beneath the skin surrounding the eye socket, responsible for closing eyelids, blinking, and squinting/smiling.

Orbicularis Oris

A complex circular muscle that surrounds the mouth and forms the majority of the lips.

Temporalis

A cranial structure situated at the sides and base of the skull near the ears.

Flat Bone

A bone type consisting of a layer of spongy bone sandwiched between two thin layers of compact bone; contains marrow but lacks a distinct marrow cavity (e.g., skull bones, sternum, ribs, scapula).

Long Bone

A bone possessing a shaft and two ends that is longer than it is wide, having a thick outer layer of compact bone enclosing a marrow-filled cavity with spongy bone at the ends (e.g., femur, collarbone).

Irregular Bone

A bone consisting of thin layers of spongy bone surrounded by compact bone that does not fit into flat, long, or short bone categories (e.g., vertebrae, pelvic bones, jaw bone).

Short Bone

A cube-shaped bone whose vertical and horizontal dimensions are approximately equal, composed mostly of spongy bone covered by a thin outer layer of compact bone (e.g., wrist and ankle bones).

True Ribs

Rib pairs $1\text{--}7$ that attach directly to the sternum through their own individual pieces of costal cartilage.

False Ribs

Rib pairs $8\text{--}10$ that do not connect directly to the sternum; their costal cartilages merge and attach to the cartilage of the rib immediately above them.

Floating Ribs

The lowest false rib pairs ($11\text{--}12$) that lack any anterior sternal attachment, ending freely in the muscles of the abdominal wall.

Epimysium

The outermost sheath of connective tissue surrounding an entire skeletal muscle.

Perimysium

Connective tissue that bundles muscle fibers into casings known as fascicles.

Endomysium

Delicate connective tissue surrounding each individual muscle fiber.

Sarcomere

The functional contracting unit of a striated muscle fiber spanning between two Z-discs.

Actin

Thin protein filament anchored to the Z-disc that contains binding sites for myosin heads during contraction.

Myosin

Thick protein filament equipped with heads that attach to actin to form cross-bridges and execute the power stroke.

Troponin and Tropomyosin

Regulatory proteins situated on actin filaments; calcium binds to troponin, causing tropomyosin to move aside and unblock actin's binding sites.

Titin

A large elastic structural protein that anchors myosin to the Z-disc and supplies spring-like recoil to the sarcomere.

Sarcoplasmic Reticulum

A specialized organelle within muscle cells that stores and releases calcium ($Ca^{2+}$) upon excitation by a motor neuron.

Acetylcholine (ACh)

The chemical neurotransmitter released from a motor neuron axon into the neuromuscular junction to trigger an electrical impulse in a muscle cell.

Neuromuscular Junction

The gap or synapse where the terminal end of a motor neuron axon meets the muscle cell membrane.

Adenosine Triphosphate (ATP)

A molecule composed of adenosine and three phosphate groups that provides the biochemical energy necessary for the myosin power stroke and muscle contraction.

Sliding Filament Theory

The mechanism of muscle contraction whereby thick and thin protein filaments slide past each other, shortening sarcomeres and pulling Z-lines closer while filament lengths remain unchanged.

Popliteus

A leg muscle originating at the back of the knee and inserting on the posterior surface of the tibia that acts as a knee flexor during activities like walking and sitting.

Rectus Femoris

A thigh muscle originating on the spine and hip and inserting onto the base of the patella and tibial tuberosity; acts to extend the knee and flex the thigh at the hip.

Vastus Intermedius

A deep quadriceps muscle originating on the shaft of the femur and inserting onto the patella and tibial tuberosity that extends the knee joint.

Gastrocnemius

A superficial calf muscle originating on the medial condyle of the femur and inserting into the calcaneus via the calcaneal tendon; flexes the knee and plantarflexes the ankle.

Ligament

A fibrous connective tissue band that connects bone to bone across a joint.

Joint (Articulation)

The junction where two or more bones meet to permit movement and provide structural support; structurally considered the weakest part of the skeleton.

Fibrous Joint

An immovable articulation where bones are joined tightly by dense collagen fibers (e.g., skull sutures).

Cartilaginous Joint

A joint allowing slight movement where cartilage fills the space between articulating bone surfaces.

Synovial Joint

A freely movable articulation containing a fluid-filled cavity with synovial fluid that reduces friction between moving surfaces.

Plane Joint

A synovial joint with flat articular surfaces that permit gliding motions (e.g., intercarpal and intertarsal joints).

Hinge Joint

A synovial joint where a cylindrical projection of one bone fits into a trough-shaped concave depression of another bone to permit motion in one plane.

Pivot Joint

A synovial joint wherein the rounded end of one bone articulates within a sleeve or ring formed by another bone or ligament.

Ball and Socket Joint

A multiaxial synovial joint where the spherical head of one bone fits into the cup-like socket of another, allowing the widest range of motion.

Condyloid Joint

A synovial joint in which an oval-shaped convex articular surface fits into a complementary elliptical depression of another bone.

Saddle Joint

A synovial joint characterized by both concave and convex articular surfaces resembling a rider in a saddle, providing greater flexibility than condyloid joints.

Flexion

A bending movement that decreases the angle between articulating bones at a joint.

Extension

A straightening motion that increases the angle between two articulating bones.

Hyperextension

The extension of a joint beyond its normal anatomical alignment past $180^\circ$.

Dorsiflexion

Lifting the foot upward at the ankle joint so that the dorsal surface and toes point toward the shin.

Plantar Flexion

Depressing the foot downward at the ankle joint, pointing the toes away from the shin.

Abduction

Movement of a limb or digit away from the midline of the body in the coronal plane.

Adduction

Movement of a limb or digit toward the midline of the body in the coronal plane.

Circumduction

Movement of a distal limb segment in a circular pattern such that the path outlines the shape of a cone.

Rotation

The turning of a bone around its own longitudinal axis.

Elevation

Lifting or moving an anatomical part superiorly (e.g., shrugging the shoulders upward).

Depression

Moving an elevated anatomical part inferiorly to a lower position (e.g., opening the mouth).

Osteoblasts

Bone-building cells responsible for synthesizing and depositing the calcium-rich bone matrix at sites of injury and growth.

Osteoclasts

Bone-resorbing cells that break down and remove mineralized bone calcium matrix during remodeling and repair.

Modeling Fracture Pattern

The simulation and study of how cracks, breaks, or flaw lines form and distribute through bone tissue.

Closed Reduction

The realigning and setting of broken bone fragments into their normal anatomical positions without surgical incision.

Open Reduction

The surgical realignment and fixation of fractured bone fragments through an operative incision.

Transverse Fracture

A bone fracture where the break line occurs horizontally straight across the bone shaft.

Oblique Fracture

A bone break that occurs diagonally at an angle across the bone axis.

Spiral Fracture

A fracture pattern where the break line curves or twists around the shaft of the bone due to rotational force.

Comminuted Fracture

A severe break where the bone shatters or splinters into $3$ or more pieces.

Segmental Fracture

A bone fracture marked by two distinct break sites along a shaft that isolate a central 'floating' bone segment.

Greenstick Fracture

An incomplete break where one side of the bone cracks and the other side bends and splinters; common in children.

Stress Fracture

A thin, hairline crack in a bone that develops from repeated mechanical overuse rather than a single traumatic impact.