Cells, Tissues, and Membranes Lecture Review

Vocabulary flashcards covering human cells, cytoplasmic organelles, cellular transport, cell division, histological tissue types, epithelial classifications, cell connections, and gland structures.

Cell

The basic microscopic building block and fundamental unit of a living thing, composed of a plasma membrane and cytoplasm containing organelles.

Cell Size

Microscopic size measuring $.0004$ inches (four ten-thousandths of an inch).

Plasma Membrane (Cell Membrane)

An outer double layer of lipids and proteins that protects internal cell structures, regulates the exchange of substances, and engulfs materials.

Nucleus

The central organelle enclosed by a nuclear envelope that directs cell activities, regulates growth and metabolism, and contains hereditary genes.

Nuclear Envelope

A double membrane containing nuclear pores that surrounds and encloses the cell nucleus.

Nucleolus

A structure within the nucleus that assists in protein synthesis and the production of ribosomes.

Cytoplasm

The fluid portion (cytosol) filling about one-third of the cell where organelles float freely.

Cytosol

The fluid portion of the cytoplasm.

Mitosis

The process of cell division responsible for cell growth and tissue repair.

Meiosis

The specialized type of cell division involved in sex cell production.

Cytoskeleton

A network of protein filaments that provides structural support, maintains cell shape, and enables movement.

Actin Filaments

Protein structures responsible for all cell movement and playing a key role in muscle contraction.

Ribosomes

Protein synthesizers that build long chains of amino acids; found floating free in the cytoplasm or attached to the rough endoplasmic reticulum.

Rough Endoplasmic Reticulum

Organelle studded with ribosomes involved in the production, folding, quality control, and dispatch of proteins.

Smooth Endoplasmic Reticulum

Organelle responsible for lipid, phospholipid, and steroid synthesis, lipid metabolism, and calcium storage; found in testes, ovaries, and skin oil glands.

Golgi Apparatus

A series of pancake-shaped membranes that modify, package, sort, and distribute proteins and lipids for secretion or internal use.

Golgi Vesicle

Vesicles pinched off from Golgi membranes that float through the cell.

Mitochondria

The powerhouse of the cell responsible for cellular respiration to continuously supply energy to the cell.

Lysosome

Organelle created by the Golgi apparatus that digests excess or worn-out organelles, food particles, and engulfed viruses or bacteria.

Peroxisome

Organelle responsible for oxidation reactions that break down fatty acids and amino acids, and neutralizes free radicals that cause cellular damage and cell death.

Secretory Vesicle

Organelle that stores and transports substances to and from one cell or cell part to another.

Centrosome

The microtubule organizing center that regulates the cell cycle through the assembly of microtubules.

Microtubules

Cytoskeletal components involved in moving chromosomes, attaching to and splitting paired chromosomes into daughter cells during division.

Intermediate Filaments

Cytoskeletal components that provide mechanical strength and structural support for the plasma membrane without participating in cell motility.

Microfilaments

Thin protein structures that hold, give shape to the cell, and facilitate movement.

Vacuole

Structure that stores cell nutrients (such as NaCl, water, proteins, and carbohydrates) and isolates waste products to protect the cell from contamination.

Chromatin

Structure that compresses DNA into a less voluminous unit within the nucleus.

Active Transport

Cellular movement mechanism requiring energy to move substances from lower to higher concentrations.

Passive Transport

Cellular movement mechanism requiring no energy to move substances from higher to lower concentrations.

Tissues

Groups of specialized cells and the surrounding extracellular matrix.

Histology

The microscopic study of tissues.

Primary Tissue Types

The four main classifications of body tissues: epithelial, connective, muscle, and nervous tissue.

Epithelial Tissue (Epithelium)

A primary tissue type consisting mostly of cells that covers and protects internal and external body surfaces.

Apical Surface (Free Surface)

The unattached, exposed surface of an epithelial cell layer.

Basal Surface

The lower surface of an epithelial layer attached and anchored to the basement membrane.

Basement Membrane

A specialized membrane structure anchoring epithelial tissue to underlying connective tissue.

Avascular

Lacking a direct blood supply, a characteristic feature of epithelial tissue.

Simple Epithelium

Epithelial tissue composed of a single layer of cells.

Stratified Epithelium

Epithelial tissue composed of multiple layers of cells.

Squamous Cells

Flat-shaped epithelial cells.

Cuboidal Cells

Cube-shaped epithelial cells.

Columnar Cells

Tall, column-shaped epithelial cells.

Simple Squamous Epithelium

A single layer of thin, flat cells through which select substances can pass.

Simple Cuboidal Epithelium

A single layer of cube-like cells specialized for active transport, facilitated diffusion, or secretion.

Simple Columnar Epithelium

A single layer of tall, thin cells performing complex functions; can be ciliated to move mucus or non-ciliated.

Stratified Squamous Epithelium

A thick tissue formed by several layers of cells providing protection.

Pseudostratified Columnar Epithelium

A single layer of cells that appears stratified due to differing cell heights and nuclear positions.

Transitional Epithelium (Urothelium)

A specialized type of stratified epithelium capable of stretching.

Desmosomes

Cell connections that bind adjacent epithelial cells together.

Hemidesmosomes

Cell connections that bind epithelial cells to the basement membrane.

Tight Junctions

Cell connections that form barriers and anchor epithelial cells to one another.

Adhesion Belts

Structures located below tight junctions that assist tight junctions in anchoring cells together.

Glands

Specialized secretory organs categorized as either endocrine or exocrine.

Endocrine Glands

Ductless glands that produce chemicals called hormones directly into body fluids.

Exocrine Glands

Glands with ducts that secrete products such as saliva, sweat, and digestive tract secretions.

Goblet Cells

Unicellular exocrine glands that secrete mucus.

Simple Glands

Multicellular exocrine glands featuring unbranched ducts.

Compound Glands

Multicellular exocrine glands featuring several branched ducts.

Simple Tubular Gland

A simple gland forming a straight tube with an unbranched secretory portion.

Simple Branched Tubular Gland

A simple gland with several tubular secretory portions branching from a single duct.

Simple Acinar Gland

A simple gland with a single saclike secretory portion.

Simple Branched Acinar Gland

A simple gland with several saclike secretory portions branching from a single duct.

Compound Tubular Gland

A compound gland with multiple ducts, each terminating in a narrow tubular secretory portion.

Compound Acinar Gland

A compound gland with multiple ducts, each terminating in several saclike secretory portions.

Compound Tubuloacinar Gland

A compound gland with multiple ducts featuring a combination of tubular and acinar secretory portions.