Plasma Membrane Structure and Function

A comprehensive set of vocabulary flashcards covering the structure and function of the plasma membrane, cellular mechanisms, diverse epithelial and connective tissues, as well as neural and muscular systems.

Plasma Membrane

The boundary of the cell composed of lipids, proteins, and carbohydrates.

Intracellular

The face of the plasma membrane that faces the interior of the cell.

Extracellular

The face of the plasma membrane that faces the external environment.

Active Mechanisms

Transport processes that require ATP, like active transport and vesicular transport.

Carrier-mediated mechanisms

Transport mechanisms that use a membrane protein to move substances across the membrane.

Phospholipids

Amphipathic molecules that comprise 75% of membrane lipids, forming a bilayer.

Amphipathic

Having both hydrophilic (water-attracting) and hydrophobic (water-repelling) parts.

Hydrophilic

Water-attracting regions, such as the phosphate heads of phospholipids.

Hydrophobic

Water-repelling regions, such as the fatty acid tails of phospholipids.

Cholesterol

A component of membrane lipids that helps maintain membrane fluidity and rigidity.

Glycolipids

Phospholipids with attached carbohydrate chains, contributing to the glycocalyx.

Membrane Proteins

Proteins that form 2% of membrane molecules but account for 50% of its weight.

Integral Proteins

Membrane proteins that penetrate the lipid bilayer; some are transmembrane.

Transmembrane Proteins

Integral proteins that pass completely through the membrane.

Peripheral Proteins

Proteins that adhere to one face of the membrane without penetrating it.

Receptors

Proteins that bind to chemical signals, initiating cellular responses.

Enzymes

Proteins that catalyze chemical reactions within the cell membrane.

Channels

Proteins that allow specific molecules to pass through the membrane.

Gated Channels

Channels that open or close in response to stimuli, such as ligands or voltage changes.

Ligand-gated Channels

Channels that open in response to binding of a chemical messenger.

Voltage-gated Channels

Channels that open or close in response to changes in membrane potential.

Cell-identity Markers

Glycoproteins that act as identification tags on cell surfaces.

Cell-adhesion Molecules

Proteins that mechanically link cells to each other or to the extracellular material.

Second messenger systems

Intracellular signaling pathways activated by surface receptors through G proteins.

Glycocalyx

A fuzzy coating around the cell surface made of carbohydrate moieties.

Immunity to infection

Function of the glycocalyx allowing immune systems to recognize foreign entities.

Transplant Compatibility

A trait of the glycocalyx that assists in blood transfusions and organ transplants.

Microvilli

Extensions of the plasma membrane that increase surface area for absorption.

Cilia

Hair-like processes that can be motile or nonmotile, involved in sensory processes.

Axoneme

Core structure of motile cilia consisting of microtubules arranged in a specific pattern.

Flagella

A whip-like structure for movement, exemplified by sperm tails.

Pseudopods

Changing extensions of the cell used for locomotion and capturing particles.

Passive Mechanisms

Transport processes that do not require ATP, such as diffusion and osmosis.

Diffusion

Movement of particles from a region of higher concentration to lower concentration.

Osmosis

The movement of water across a semi-permeable membrane.

Tonicity

Ability of a surrounding solution to affect cell volume and pressure.

Hypotonic Solution

A solution that causes cells to swell due to gaining water.

Hypertonic Solution

A solution that causes cells to lose water and shrivel.

Isotonic Solution

A solution that does not change the volume of cells.

Carrier-mediated Transport

Transport system using proteins to carry specific solutes across the membrane.

Uniport

A type of carrier that transports a single type of solute.

Symport

A carrier that transports two or more solutes simultaneously in the same direction.

Antiport

A carrier that transports two or more solutes in opposite directions.

Facilitated Diffusion

Passive transport method utilizing a carrier protein to assist solute movement.

Primary Active Transport

Active transport using ATP to move a solute against its concentration gradient.

Secondary Active Transport

Transport that depends on the primary active transport process.

Vesicular Transport

Transport of large particles or volumes through vesicles.

Endocytosis

Vesicular process that brings materials into the cell.

Phagocytosis

Endocytosis of large particles, often referred to as 'cell eating'.

Pinocytosis

Endocytosis of fluids and small molecules, also known as 'cell drinking'.

Receptor-mediated Endocytosis

Selective uptake of substances via receptor binding.

Exocytosis

Process of discharging materials from the cell.

Transcytosis

Transport of materials across the cell, capturing on one side and releasing on the other.

Epithelial Tissue

Tissue that covers body surfaces and lines body cavities.

Connective Tissue

Tissue that supports, binds, and protects organs.

Nervous Tissue

Tissue that transmits signals through electrical impulses.

Muscular Tissue

Tissue responsible for movement of the body and substances within it.

Simple Epithelia

Epithelial tissue consisting of a single layer of cells.

Stratified Epithelia

Epithelial tissue composed of multiple layers of cells.

Pseudostratified Columnar Epithelium

Epithelial tissue that appears stratified but every cell touches the basement membrane.

Squamous Cells

Flat and scaly epithelial cells.

Cuboidal Cells

Square or round epithelial cells.

Columnar Cells

Tall, narrow epithelial cells.

Simple Squamous Epithelium

Single layer of thin cells that allows rapid diffusion.

Simple Cuboidal Epithelium

Single layer of cube-shaped cells involved in absorption and secretion.

Simple Columnar Epithelium

Single layer of tall cells that often have microvilli or cilia.

Goblet Cells

Mucus-secreting cells found in certain epithelial tissues.

Stratified Squamous Epithelium

Multiple layers of cells; protection against abrasion.

Keratinized Epithelium

Epithelial tissue that contains a superficial layer of dead cells resistant to abrasion.

Nonkeratinized Epithelium

Epithelial tissue without a layer of dead cells.

Transitional Epithelium

Epithelial tissue that can stretch; lines the bladder.

Loose Connective Tissue

Connective tissue with abundant ground substance and scattered cells.

Dense Connective Tissue

Connective tissue with densely packed fibers.

Fibrous Proteins

Proteins that provide strength and support to connective tissues.

Adipose Tissue

Connective tissue that stores fat.

Cartilage

Flexible connective tissue that provides support.

Bone

Dense, hard connective tissue composed of osteocytes.

Blood

Fluid connective tissue that transports cells and dissolved matter.

Skeletal Muscle

Voluntary muscle tissue that moves bones.

Cardiac Muscle

Involuntary muscle found in the heart; contracts rhythmically.

Smooth Muscle

Involuntary muscle found in walls of hollow organs.

Motor Unit

A motor neuron and all the muscle fibers it innervates.

Neuromuscular Junction

The synapse or junction where a motor neuron meets a muscle fiber.

Resting Membrane Potential

The voltage difference across the plasma membrane of a resting neuron.

Action Potential

A rapid change in membrane potential that propagates along an axon.

Synaptic Vesicles

Structures that release neurotransmitters into the synaptic cleft.

Neurotransmitter

Chemicals released by neurons to communicate with other cells.

Nervous Tissue

Tissue that transmits electrical signals throughout the body.

Dendrites

Branch-like structures of neurons that receive signals from other neurons.

Axon Terminals

The end of an axon where neurotransmitters are released.

Neuroglia

Supporting cells in the nervous system that protect and assist neurons.

Astrocytes

Star-shaped glial cells that provide support and nutrition to neurons.

Oligodendrocytes

Glial cells that produce the myelin sheath in the central nervous system.

Schwann Cells

Glial cells that produce the myelin sheath in the peripheral nervous system.

Myelin Sheath

Insulating layer around nerve fibers that speeds up signal transmission.

Nodes of Ranvier

Gaps in the myelin sheath between Schwann cells.

Synapse

The junction between two neurons or a neuron and a muscle.

Excitability

The ability of neurons to respond to stimuli.

Conductivity

The ability of neurons to transmit electrical impulses.

Action Potential

A rapid rise and subsequent fall in voltage or membrane potential across a cellular membrane.