Human Body Orientation, Cell Biology, and Histology Flashcards

Comprehensive vocabulary flashcards covering human anatomy and body orientation, epithelial and connective tissues, cellular structures, organelles, membrane transport, cell division, and protein synthesis based on Chapter 1 and Chapter 3 lecture notes.

Anatomy

The study of the structure of body parts and their relationship to one another.

Physiology

The study of the function of body parts.

Gross Anatomy

The study of large, easily observable body structures (also known as macroscopic anatomy).

Microscopic Anatomy

The study of body structures that are too small to be seen with the naked eye.

Homeostasis

The body's ability to maintain relatively stable internal conditions even though the outside world changes continuously.

Homeostatic Control System

A control system pathway operating through a stimulus, receptor, afferent pathway, control center, efferent pathway, effector, and response to maintain balance.

Negative Feedback Mechanism

A homeostatic control mechanism where the output shuts off the original effect of the stimulus or reduces its intensity.

Positive Feedback Mechanism

A homeostatic control mechanism where the response enhances the original stimulus so that the activity is accelerated.

Superior (Cranial or Cephalad)

Toward the head end or upper part of a structure or the body; above.

Inferior (Caudal)

Away from the head end or toward the lower part of a structure or the body; below.

Ventral (Anterior)

Toward or at the front of the body; in front of.

Dorsal (Posterior)

Toward or at the backside of the body; behind.

Medial

Toward or at the midline of the body; on the inner side of.

Lateral

Away from the midline of the body; on the outer side of.

Intermediate

Between a more medial and a more lateral structure.

Proximal

Close to the origin of the body part or the point of attachment of a limb to the body trunk.

Distal

Farther from the origin of a body part or the point of attachment of a limb to the body trunk.

Superficial (External)

Toward or at the body surface.

Deep (Internal)

Away from the body surface; more internal.

Apical Surface

The unattached free surface or edge of an epithelial tissue exposed to the body exterior or an organ cavity.

Basement Membrane

A structureless material secreted by epithelial cells and connective tissue upon which the lower surface of epithelium rests.

Endocrine Glands

Ductless glands whose secretions (hormones) diffuse directly into blood vessels.

Exocrine Glands

Glands that retain their ducts and empty secretions through these ducts to the epithelial surface.

Extracellular Matrix

Nonliving material surrounding living cells in connective tissue, composed of ground substance and fibers.

Osteocytes

Bone cells residing in cavities called lacunae within osseous tissue.

Chondrocytes

Cartilage cells, which serve as the primary cell type in cartilage tissues.

Hyaline Cartilage

The most widespread cartilage type, composed of abundant collagen fibers and a rubbery matrix, located in the larynx, fetal skeleton, and epiphyseal plates.

Fibrocartilage

A highly compressible type of cartilage forming cushion-like discs between the vertebrae of the spinal column.

Tendons

Dense fibrous connective tissue structures that attach skeletal muscle to bone.

Ligaments

Dense fibrous connective tissue structures that attach bone to bone at joints.

Areolar Tissue

The most widely distributed loose connective tissue; a soft, pliable packing tissue that cushions and holds organs in place.

Lamina Propria

A soft layer of areolar connective tissue underlying all mucous membranes.

Adipose Tissue

Loose connective tissue dominated by cells containing large fat globules, functioning in body insulation, organ protection, and fuel storage.

Reticular Connective Tissue

Loose connective tissue made of interwoven reticular fibers that form the stroma (internal framework) of lymphoid organs like lymph nodes, spleen, and bone marrow.

Peristalsis

A wavelike involuntary muscular contraction characteristic of smooth muscle in hollow organs.

Neuroglia

Specialized nerve support cells that insulate, protect, and support neurons in nervous tissue.

Regeneration

The replacement of destroyed tissue by the exact same kind of cells during wound healing.

Fibrosis

Tissue repair involving the replacement of damaged tissue with dense fibrous connective tissue (scar tissue).

Hyperplasia

An increase in the size of a tissue or organ that occurs when it is strongly stimulated or irritated.

Atrophy

A decrease in the size of a tissue or organ that occurs when it is no longer normally stimulated.

Nuclear Envelope

The double membrane bounding the nucleus that contains nuclear pores and encloses nucleoplasm.

Nucleoli

Dark-staining nuclear structures that serve as sites of ribosome assembly.

Chromatin

A loose network of DNA and protein scattered throughout the nucleus when a cell is not dividing.

Hydrophilic

"Water-loving"; describes polar phospholipid heads oriented on the outer and inner surfaces of the plasma membrane.

Hydrophobic

"Water-hating"; describes nonpolar phospholipid tails forming the interior of the plasma membrane, rendering it impermeable to most water-soluble molecules.

Glycocalyx

The sticky, sugar-rich area on the cell's surface formed by glycoproteins.

Tight Junctions

Impermeable membrane junctions that bind cells into leakproof sheets to prevent substances from passing through intercellular space.

Desmosomes

Anchoring junctions formed by buttonlike thickenings of adjacent plasma membranes that prevent cells from pulling apart under mechanical stress.

Gap Junctions

Communicating membrane junctions composed of hollow protein cylinders (connexons) that allow direct passage of molecules between cells.

Cytosol

The semitransparent fluid portion of the cytoplasm in which cellular elements are suspended.

Mitochondria

"Powerhouses" of the cell containing double membranes with inner cristae, responsible for carrying out oxygen-using reactions to yield ATP.

Ribosomes

Bilobed dark bodies made of protein and ribosomal RNA that act as the primary sites of protein synthesis.

Rough Endoplasmic Reticulum

A fluid-filled tubule network studded with ribosomes that synthesizes and transports proteins via transport vesicles.

Smooth Endoplasmic Reticulum

A fluid-filled tubule network lacking ribosomes that functions in lipid metabolism and drug/pesticide detoxification.

Golgi Apparatus

A stack of flattened membranous sacs that modifies, packages, and routes proteins received from the rough ER via transport vesicles.

Lysosomes

Membranous sacs packaged by the Golgi apparatus containing hydrolytic enzymes that digest worn-out organelles and foreign material.

Peroxisomes

Membranous sacs containing oxidase enzymes that detoxify harmful substances and neutralize free radicals into hydrogen peroxide and water.

Microfilaments

The smallest cytoskeletal elements ($7\,\text{nm}$ diameter) composed of actin subunits, involved in cell mobility and shape changes.

Intermediate Filaments

Cytoskeletal elements ($10\,\text{nm}$ diameter) made of fibrous subunits that form internal guy wires to resist pulling forces on the cell.

Microtubules

The largest cytoskeletal elements ($25\,\text{nm}$ diameter) composed of tubulin subunits, determining overall cell shape and organelle arrangement.

Microvilli

Tiny, fingerlike projections of the plasma membrane that increase cell surface area for absorption.

Sodium-Potassium Pump

An active transport solute pump energized by ATP that pumps sodium ($\text{Na}^+$) out of the cell and potassium ($\text{K}^+$) into the cell.

v-SNAREs

Transmembrane proteins located specifically on vesicle membranes that bind to t-SNAREs on the target membrane during exocytosis.

t-SNAREs

Target transmembrane proteins located on the plasma membrane that bind with v-SNAREs to initiate membrane fusion during exocytosis.

Phagocytosis

"Cell eating"; an active endocytic process where pseudopods engulf large particles or bacteria into a phagosome.

Pinocytosis

"Cell drinking"; an active endocytic process in which the cell engulfs droplets of extracellular fluid containing dissolved proteins or fats.

Receptor-Mediated Endocytosis

A highly selective endocytic method where specific target molecules bind to plasma membrane receptors before being internalized in a vesicle.

Mitosis

Division of the cell nucleus, resulting in the formation of two identical daughter nuclei.

Cytokinesis

Division of the cytoplasm during cell division, forming a contractile cleavage furrow made of microfilaments that pinches the cell into two.

Codons

Three-base sequences on mRNA that correspond to DNA triplets and specify particular amino acids during translation.

Anticodons

Three-base sequences on tRNA molecules that recognize and bind to complementary codons on mRNA.

Transcription

The transfer of genetic information from a DNA gene's base sequence (triplets) to a complementary mRNA base sequence (codons) in the nucleus.

Translation

The process at the ribosome where the base sequence of mRNA is translated into an amino acid sequence to construct a protein.