Week 3 LPN A&P

Cells

The smallest structural units of living things, all of which are microscopic.

Cytoplasm

The living, gel-like fluid inside the cell (found only in cells) that forms the internal environment, holds organelles in position, and allows substances to move within the cell.

Organelles

Specialized structures or "little organs" located within the cytoplasm of a cell.

Plasma membrane

The outer boundary of a cell composed of a thin, two-layered membrane of phospholipids containing proteins and cholesterol that is selectively permeable.

Interstitial fluid (IF)

Tissue fluid that surrounds and bathes every cell.

Nucleus

Small circular body that serves as the central control center of the cell and contains genetic code (DNA).

Ribosomes

Organelles made of two tiny subunits of mostly ribosomal RNA that manufacture enzymes and other protein compounds; often called protein factories.

Endoplasmic Reticulum (ER)

A network of connecting sacs and canals that carry substances through the fluid cytoplasm.

Rough Endoplasmic Reticulum

Type of endoplasmic reticulum that collects, folds, and transports proteins made by ribosomes.

Smooth Endoplasmic Reticulum

Type of endoplasmic reticulum that synthesizes chemicals and makes new membrane.

Golgi apparatus

A group of flattened sacs near the nucleus that serves as the chemical processing and packaging center for proteins and molecules received from the ER.

Mitochondria

Organelles composed of inner and outer membranous sacks that break down nutrients to release energy and recharge ATP, known as the power plant of the cell.

Lysosomes

Membranous-walled organelles containing digestive enzymes that break down nutrients, foreign microbes, and other substances.

Centrosome

A region of cytoplasm near the nucleus that acts as the microtubule-organizing center of the cell and contains centrioles.

Centrioles

Paired organelles lying at right angles within the centrosome that function in cell reproduction by moving chromosomes during cell division.

Microvilli

Small, fingerlike extensions of the plasma membrane that increase the absorptive surface area of the cell.

Cilia

Fine, hairlike extensions on free surfaces of certain cells that move in unison in a wavelike fashion.

Flagella

Single, large projections extending from cell surfaces, such as the tail of a sperm cell.

Nuclear envelope

Structure surrounding the nucleus composed of two separate membranes containing nuclear pores.

Nucleolus

Dense region of nuclear material that creates subunits of ribosomes and is critical in protein formation.

Chromatin

Component structure inside the nucleus composed of DNA that condenses into tightly coiled chromosomes during cell division.

Chromosomes

Tightly coiled structures formed from DNA molecules during cell division, numbering $46$ in each human cell nucleus.

Passive transport

Movement of substances across cell membranes down a concentration gradient without requiring added energy.

Active transport

Movement of substances across cell membranes up a concentration gradient requiring energy from adenosine triphosphate (ATP).

Diffusion

Passive transport process where substances scatter themselves evenly throughout an available space from an area of high concentration to low concentration.

Osmosis

Passive movement or diffusion of water across a selectively permeable membrane when certain solutes cannot cross.

Dialysis

Diffusion of solutes across a selectively permeable membrane.

Filtration

Movement of water and solutes across a membrane caused by hydrostatic pressure on one side.

Ion pumps

Protein complexes in the cell membrane that use energy from ATP to move substances across cell membranes against their concentration gradients.

Phagocytosis

An active transport mechanism used as a protective mechanism to ingest and destroy bacteria or particles.

Pinocytosis

An active transport mechanism used to incorporate fluids or dissolved substances into cells.

Cystic fibrosis

Disease characterized by abnormally thick secretions in the airways and digestive ducts resulting from failed $Cl^-$ transport.

Cholera

A bacterial infection causing $Cl^-$ and water to leak from cells lining the intestines, resulting in severe diarrhea and water loss.

DNA

Double-helix molecule composed of deoxyribose sugar, phosphate units, and nitrogenous bases (adenine, thymine, guanine, cytosine) containing genetic instructions for protein synthesis.

Gene

A specific segment of base pairs in a chromosome that dictates protein synthesis and controls enzyme production.

Transcription

The process of protein synthesis where a double-stranded DNA segment separates to form a complementary mRNA transcript inside the nucleus.

Translation

The process in protein synthesis where ribosomes in the cytoplasm read mRNA codons to assemble amino acids into polypeptide chains.

Codon

A series of three nucleotide bases in mRNA that acts as a code for a specific amino acid.

Interphase

The period in the cell life cycle when the cell is not actively dividing and DNA replication occurs.

DNA replication

The process preceding mitosis by which each half of a DNA molecule becomes a whole molecule identical to the original.

Mitosis

Process of cell division involving division of the nucleus that distributes identical chromosomes to two resulting daughter cells.

Prophase

First stage of mitosis during which chromatin condenses into visible chromosomes, centrioles move away from the nucleus, spindle fibers appear, and the nuclear envelope disappears.

Metaphase

Second stage of mitosis where chromosomes align across the center of the cell and spindle fibers attach to each chromatid.

Anaphase

Third stage of mitosis where centromeres break apart, separated chromosomes move to opposite ends of the cell, and a cleavage furrow develops.

Telophase

Fourth and final stage of mitosis where nuclear envelopes reappear, cytoplasm divides (cytokinesis), and two functional daughter cells are formed.

Hypertrophy

Increase in the size of individual cells, resulting in an increased size of tissue.

Atrophy

Decrease in the size of individual cells, resulting in a decreased size of tissue.

Hyperplasia

Increase in the rate of cell reproduction, resulting in an increased size of tissue.

Anaplasia

Production of abnormal, undifferentiated cells.

Extracellular Matrix (ECM)

Cellular structures and fluid that hold tissues, organs, and systems together outside the cells; primarily composed of water, fibers, and other substances.

Plasma

The liquid matrix of blood, which contains no fibers except when clotting.

Collagen

A protein that forms ropelike fibers to provide flexible strength to tissues.

Elastin

A rubbery protein that provides elastic strength and recoil in tissues.

Epithelial Tissue

Tissue that covers the body and lines body cavities, consisting of closely packed cells with little matrix and no blood vessels.

Squamous Cells

Epithelial cells that are flat and scale-like.

Cuboidal Cells

Epithelial cells that are cube-shaped.

Columnar Cells

Epithelial cells that are taller than they are wide.

Transitional Cells

Epithelial cells of varying shapes that can stretch.

Simple Epithelium

Epithelial tissue composed of a single layer of cells of the same shape.

Stratified Epithelium

Epithelial tissue composed of many layers of cells, named for the shape of the cells in the outer layer.

Simple Squamous Epithelium

A single layer of scalelike epithelial cells specialized for transport, such as absorption in the alveoli of the lungs.

Stratified Squamous Epithelium

Epithelial tissue consisting of several layers of closely packed cells whose primary function is protection.

Exocrine Glands

Glands that release their secretions through a duct.

Endocrine Glands

Glands that release their secretions directly into the bloodstream.

Goblet Cells

Mucus-producing cells found within simple columnar epithelium.

Pseudostratified Epithelium

Epithelium that appears to have multiple layers but is only a single layer where every cell touches the basement membrane; lines the trachea and windpipe.

Stratified Transitional Epithelium

Epithelial tissue found in stretching areas such as the urinary bladder, containing up to 10 layers of roughly cuboidal cells that distort to a squamous shape when stretched.

Connective Tissue

The most abundant and widely distributed tissue in the body, characterized by relatively few cells in an intercellular matrix to form a supporting framework.

Areolar Connective Tissue

Loose fibrous connective tissue that acts as glue holding organs together.

Adipose Tissue

Fat tissue specialized for lipid storage that secretes hormones regulating metabolism and fuel storage.

Osteon

The structural building block unit of compact bone, also known as a haversian system.

Cancellous Bone

Spongy bone tissue found inside bones with spaces filled with hematopoietic or adipose tissue.

Chondrocyte

A specialized cartilage cell.

Hyaline Cartilage

The most common cartilage type in the body, translucent in appearance with moderate collagen, found in trachea rings and covering ends of bones at joints.

Fibrocartilage

The strongest and most durable cartilage with a matrix dense with collagen, functioning as shock absorbers in intervertebral disks and knee joints.

Elastic Cartilage

Cartilage with a matrix containing few collagen fibers and many elastic fibers, located in the external ear and part of the larynx.

Skeletal Muscle Tissue

Striated, voluntary muscle tissue attached to bones.

Cardiac Muscle Tissue

Striated, involuntary muscle tissue composing the wall of the heart.

Smooth Muscle Tissue

Nonstriated (visceral), involuntary muscle tissue located in blood vessels and other tube-shaped organs.

Axon

A single process of a neuron that carries nerve impulses away from the cell body.

Dendrite

A process of a neuron (one or more) that carries nerve impulses toward the cell body (soma).

Glia

Supportive and connecting cells of the nervous tissue, also known as neuroglia.

Organ

A structure made up of two or more kinds of tissues that can together perform a more complex function than a single tissue.

Organ system

A group of organs that perform a more complex function than can any organ alone.

Integumentary System

An organ system comprising only one organ—the skin—and its appendages (hair, nails, microscopic sense receptors, sweat glands, and oil glands) that functions in protection, body temperature regulation, synthesis of Vitamin D, and sensory reception.

Ligaments

Bands of fibrous tissue that hold bones together.

Joints

Connections between bones that make movement possible.

Skeletal System

The body system made of bones (206 named bones in adults, about 300 in babies), cartilage, ligaments, and joints that provides a supporting framework, protects internal organs, allows movement, stores minerals ($Ca^+$ and phosphorus), and forms blood cells in red bone marrow.

Skeletomuscular system

The combination of the skeletal and muscular systems working together.

Central nervous system (CNS)

The structural division of the nervous system consisting of the brain and spinal cord.

Peripheral nervous system (PNS)

The structural division of the nervous system consisting of cranial nerves and their branches, spinal nerves and their branches, and sense organs.

Neuroendocrine system

The combination of the nervous and endocrine systems working together to perform communication, integration, and control functions.

Cardiovascular System

Also referred to as the circulatory system; consists of the heart and blood vessels that pump blood in a closed circuit to transport substances, regulate body temperature, and provide immunity.

Lymphatic System

A body system composed of lymphatic vessels, lymph nodes, tonsils, thymus, and spleen, which functions in the transportation of lymph and immunity.

Immune System

A defensive system composed of phagocytes and secretory cells (which produce antibodies and complements) that protects the body through phagocytosis of bacteria and defensive chemical reactions.

Alimentary canal

Also known as the gastrointestinal (GI) tract; the primary pathway of the digestive system formed by the mouth, pharynx, esophagus, stomach, small intestine, large intestine, rectum, and anal canal.

Feces

Undigested waste products eliminated by the digestive system.

Urinary System

The body system consisting of the kidneys, ureters, urinary bladder, and urethra that cleans the blood of waste products excreted as urine, while maintaining electrolyte, water, and acid-base balance.

Nonvital organs

Organs whose loss of function is not immediately life-threatening.

Vital organs

Organs whose loss of function is immediately life-threatening.