BIOS 203 - Reflection 1 Exam Review

Vocabulary practice flashcards generated from Human Anatomy & Physiology I lecture review notes covering hierarchy of life, homeostasis, membrane transport, histology, and skin layers.

Organism

The largest level in the body's structural hierarchy, classified as biotic (living).

Cells

The smallest biotic (living) level in the body's structural hierarchy, positioned directly below tissues and above organelles.

Organelles

Structures within a cell that represent the first abiotic (non-living) level in the body's structural hierarchy.

Evolution

A characteristic of life in which an entire species, rather than an individual, changes over time to be more suited to a certain environment.

Homeostasis

The ability of an organism to stay at or re-regulate to a set point.

Negative Feedback Loop

A homeostatic mechanism triggered when a system goes out of equilibrium, causing the body to respond in order to return to homeostasis.

Positive Feedback Loop

A mechanism in which the body gets driven further and further out of homeostasis until the process or loop is finished.

Set Point

The specific value or target state that a negative feedback loop attempts to maintain or return to.

Receptor (Feedback Loop)

The component of a negative feedback loop that notices or detects a change in the body.

Control Center

The component of a negative feedback loop that processes detected changes and generates response instructions.

Effector

The component of a negative feedback loop that carries out the instructions provided by the control center.

Stratified Squamous Epithelium

An epithelial tissue made of multiple layers of square-shaped cells that get smaller toward the top.

Simple Columnar Epithelium

An epithelial tissue consisting of a single layer of elongated cells.

Stellate Cells

Large star-shaped cells.

Phospholipid

Molecules that make up the majority of the plasma membrane, consisting of a polar head and a non-polar tail.

Transmembrane Proteins

Proteins that extend completely through the plasma membrane.

Peripheral Proteins

Membrane proteins that sit on the outer or inner surface of the membrane rather than spanning through it.

Receptor (Membrane Protein)

Membrane-bound proteins that serve as binding sites for specific molecules.

Leak Channels

Channel proteins that remain open continuously, allowing constant movement of specific substances across the membrane.

Gated Channels

Channel proteins that require a specific stimulus or signal to activate and open.

Ligand-Gated Channel

A gated channel protein that opens in response to the binding of a chemical messenger.

Voltage-Gated Channel

A gated channel protein that opens in response to a change in membrane potential or voltage.

Mechanically-Gated Channel

A gated channel protein that opens in response to physical stress or mechanical force.

Carrier Proteins

Membrane proteins that bind to glucose and other solutes and act as pumps using $\text{ATP}$.

Cell-Identity Markers

Membrane proteins that allow cells to recognize and identify one another.

Cell Adhesion Molecules

Proteins that adhere cells to neighboring cells or extracellular materials, with the exception of blood and metastasizing cancer cells.

Second Messenger Systems

Systems that trigger intracellular changes by generating a second messenger inside the cytoplasm.

Passive Diffusion

The movement of substances across a membrane down their concentration gradient without requiring metabolic energy.

Active Diffusion

The movement of substances across a membrane that requires cellular energy.

Osmosis

The net movement specifically of water molecules across a selectively permeable membrane, differing from diffusion which applies to any type of molecule.

Isotonic Solution

A solution that has the same osmolarity as the intracellular fluid of the cell, resulting in no net movement of water.

Hypotonic Solution

A solution with a lower osmolarity than the cell, causing water to flow into the cell and leading to cell swelling.

Hypertonic Solution

A solution with a higher osmolarity than the cell, causing water to flow out of the cell and leading to cell shriveling.

Uniport

A carrier mechanism that transports only one type of solute across the membrane.

Symport

A carrier mechanism that transports two or more solutes across the membrane in the same direction.

Antiport

A carrier mechanism that transports two or more solutes across the membrane in opposite directions.

Endocytosis

The vesicular transport process by which cells bring substances into the cell.

Phagocytosis

A form of endocytosis in which large or solid particles are engulfed by a vesicle.

Pinocytosis

A form of endocytosis in which droplets of extracellular fluid (ECF) containing dissolved solutes are engulfed into vesicles.

Receptor-Mediated Endocytosis

A selective form of endocytosis in which specific target molecules bind to membrane receptors before being engulfed.

Coronal Plane

An anatomical plane that divides the body into ventral (front) and dorsal (back) halves.

Stratum Corneum

The most superficial layer of the epidermis, composed of dead, flaky keratinized cells.

Stratum Lucidum

An epidermal layer found exclusively in thick skin, containing clear keratinocytes filled with eleidin.

Stratum Granulosum

An epidermal layer consisting of three to five layers of flattened keratinocytes.

Stratum Spinosum

An epidermal layer consisting of many layers of keratinocytes along with dendritic cells; it represents the thickest layer in thin skin.

Stratum Basale

The deepest single layer of the epidermis, composed of stem cells, tactile cells, and keratinocytes, with melanocytes scattered throughout.

Melanosomes

Organelles within melanocytes where melanin is produced before being accumulated inside keratinocytes.