Human Anatomy & Physiology Midterm Review: Chapters 4 & 5

Vocabulary flashcards covering key definitions, processes, cellular structures, and tissue classifications for Chapters 4 and 5 Human Anatomy & Physiology midterm preparation.

Metabolism

The complete set of chemical reactions occurring within a cell.

Anabolism

Metabolic processes that build larger molecules from smaller molecules, requiring energy input and utilizing dehydration synthesis.

Catabolism

Metabolic processes that break down larger molecules into smaller ones, releasing energy and utilizing hydrolysis.

Dehydration synthesis

A chemical process that removes an $\text{H}_2\text{O}$ molecule to form bonds, building larger molecules.

Hydrolysis

A chemical process that uses an $\text{H}_2\text{O}$ molecule to break chemical bonds.

Enzyme

A molecule, usually a protein, that speeds up a biochemical reaction by lowering its activation energy without being consumed.

Active site

The specific region of an enzyme where the substrate binds.

Substrate

The specific molecule acted upon by an enzyme.

Cofactor

A non-protein component necessary for the activity of some enzymes, such as copper, iron, or zinc ions.

Chaperone protein

A protein that assists in folding other proteins into their proper three-dimensional structure.

Catalase

An enzyme that breaks down hydrogen peroxide into water and oxygen.

ATP (Adenosine Triphosphate)

The primary energy-transfer molecule in cells, which stores energy in high-energy phosphate bonds and releases usable energy when its terminal phosphate bond is broken.

Glycolysis

An anaerobic stage of cellular respiration occurring in the cytoplasm that breaks down glucose into $2$ pyruvate molecules, producing a net yield of $2\text{ ATP}$ and $2\text{ NADH}$.

Pyruvate conversion

The mitochondrial stage of cellular respiration where pyruvate is converted into acetyl-CoA, releasing $\text{CO}_2$ and producing $\text{NADH}$.

Krebs cycle (Citric Acid Cycle)

A pathway in the mitochondrial matrix that processes acetyl-CoA to yield $\text{ATP}$, $\text{NADH}$, $\text{FADH}_2$, and $\text{CO}_2$.

Electron Transport Chain (ETC)

A sequence of electron carriers in the inner mitochondrial membrane that creates a proton gradient to produce the majority of cellular $\text{ATP}$ along with $\text{H}_2\text{O}$, using oxygen as the final electron acceptor.

Oxidation

The loss of electrons during a chemical reaction.

Reduction

The gain of electrons during a chemical reaction.

Gene

A sequence of DNA that contains the genetic information required to construct one kind of protein.

Genome

The complete set of genetic material present in a cell.

Semi-conservative replication

The mode of DNA replication that produces two DNA molecules, each consisting of one original parental strand and one newly synthesized strand.

Polymerase Chain Reaction (PCR)

A laboratory technique used to amplify specific DNA sequences, functioning as an in vitro version of DNA replication.

Transcription

The synthesis of an mRNA molecule from a DNA template, occurring in the nucleus.

Translation

The process by which genetic code carried by mRNA is decoded at a ribosome to assemble a sequence of amino acids into a protein.

Codon

A three-nucleotide sequence on mRNA that codes for a specific amino acid or signal during translation.

Anticodon

A three-nucleotide sequence on a tRNA molecule that is complementary to a specific codon on mRNA.

Mutation

A change in the genetic code or DNA sequence of an organism.

Single Nucleotide Polymorphism (SNP)

A single nucleotide DNA sequence variant common in a population that typically has no detectable functional effects.

MicroRNAs

Small noncoding RNA molecules, approximately $21\text{–}22$ bases in length, that regulate gene expression.

DNA profiling

A technique that compares highly variable regions of the genome to distinguish between individuals.

Tissue

A group of similar cells specialized to perform a common function.

Tight junction

An intercellular junction characterized by a zipper-like seal between cell membranes that prevents extracellular leakage.

Desmosome

An intercellular junction that acts as a spot weld or rivet holding adjacent cell membranes together tightly.

Gap junction

An intercellular junction containing tubular channels that allow ions and small molecules to pass directly between adjacent cells.

Epithelial tissue

A primary tissue type characterized by tightly packed cells covering body surfaces, lining internal organs and cavities, and forming glands.

Basement membrane

An extracellular layer that anchors epithelial tissue to underlying connective tissue.

Simple squamous epithelium

A single layer of flattened epithelial cells specialized for diffusion and filtration in areas like lung air sacs and capillaries.

Simple cuboidal epithelium

A single layer of cube-shaped cells functioning in absorption and secretion, found lining kidney tubules and thyroid follicles.

Simple columnar epithelium

A single layer of elongated cells specialized for absorption and secretion, found lining the small intestine and uterus.

Pseudostratified columnar epithelium

A single layer of columnar cells appearing layered due to scattered nuclei, equipped with cilia and goblet cells to move mucus in the trachea.

Stratified squamous epithelium

Multiple layers of cells with flattened surface cells that provide protective barrier functions in the epidermis, mouth, throat, vagina, and anus.

Transitional epithelium

A specialized epithelium whose cell layers stretch and change shape under tension, providing distensibility in the urinary bladder and ureters.

Exocrine gland

A gland that secretes its products through ducts onto an internal or external surface.

Endocrine gland

A ductless gland that secretes chemical messengers (hormones) directly into the blood or tissue fluid.

Merocrine gland

A gland that releases fluid products by exocytosis without any loss of cytoplasm from glandular cells (e.g., salivary glands).

Apocrine gland

A gland that loses small portions of its glandular cell bodies during secretion (e.g., mammary glands).

Holocrine gland

A gland that releases entire disintegrating cells filled with secretory product (e.g., sebaceous glands).

Connective tissue

A primary tissue type consisting of cells within an extracellular matrix (ground substance + fibers) that functions in support, binding, protection, and transport.

Fibroblast

The most common fixed cell type in connective tissue proper, responsible for producing extracellular protein fibers.

Collagen fiber

A thick connective tissue fiber composed of collagen protein, providing high tensile strength in tendons, ligaments, and bone.

Elastic fiber

A flexible connective tissue fiber made of elastin protein that provides rubbery resiliency in skin, lungs, and blood vessels.

Reticular fiber

A thin, branched collagenous fiber forming delicate supportive networks in basement membranes and lymphatic organs.

Areolar tissue

A loose connective tissue with a gel-like matrix containing fibroblasts, collagen, and elastic fibers that cushions organs and underlies epithelia.

Adipose tissue

A connective tissue specialized for fat storage, thermal insulation, and mechanical protection, composed mainly of adipocytes.

Dense regular connective tissue

A strong connective tissue with closely packed parallel collagen fibers, found in tendons and ligaments.

Hyaline cartilage

The most common cartilage type, featuring chondrocytes in lacunae within a clear amorphous matrix, found on joint surfaces, the nose, and respiratory rings.

Fibrocartilage

A tough cartilage rich in collagen fibers that serves as a shock absorber in intervertebral discs and the pubic symphysis.

Elastic cartilage

A flexible cartilage containing abundant elastic fibers that provides structural support to the external ear and epiglottis.

Serous membrane

An epithelial membrane lining closed internal ventral body cavities, composed of simple squamous epithelium and loose connective tissue that secretes lubricating fluid.

Mucous membrane

An epithelial membrane lining body cavities and tracts that open directly to the outside environment, such as digestive and respiratory passages.

Cutaneous membrane

An epithelial membrane commonly known as skin, composed of keratinized stratified squamous epithelium and dense irregular connective tissue.

Synovial membrane

A membrane composed entirely of connective tissue that lines joint cavities and secretes lubricating synovial fluid.

Skeletal muscle

Voluntary muscle tissue attached to bones, characterized by long, cylindrical, striated cells containing multiple nuclei.

Smooth muscle

Involuntary muscle tissue consisting of non-striated, spindle-shaped cells with a single central nucleus, located in hollow organ walls and blood vessels.

Cardiac muscle

Involuntary muscle tissue located in the heart wall, characterized by branching, striated cells with a single central nucleus and intercalated discs.

Neuron

A specialized nerve cell that receives, integrates, and transmits electrical impulses.

Neuroglia

Non-neuronal supporting cells in nervous tissue that protect, nourish, insulate, and support neurons.

Carcinoma

A cancer that originates in epithelial tissue.

Histology

The microscopic study of tissues.

Platelets

Cellular fragments in blood that function in blood clotting.