Body Compartments and Cells: Applied Physiology for Mental Health Nursing

Vocabulary practice flashcards covering human body compartments, cell structure and organelles, membrane transport mechanisms, fluid balance, and homeostatic feedback loops from the Applied Physiology for Mental Health Nursing course.

Cytology

The scientific study of cell structure and function, which constitutes part of the broader discipline of cell biology.

Cranial cavity

The body compartment that contains and protects the brain and its protective coverings, the meninges.

Spinal canal

The body cavity formed within the vertebral column through which the spinal cord extends downward from the brain.

Thoracic cavity

The chest compartment containing the heart and lungs, which is physically separated from the abdominal cavity by the diaphragm.

Abdominal cavity

The body compartment containing the liver, gallbladder, stomach, small intestine, and large intestine anteriorly, and the spleen, kidneys, pancreas, and large blood vessels posteriorly.

Pelvic cavity

The lower anatomical compartment containing the bladder, urethra, bowel, and reproductive structures.

Somatic cells

The general body cells of the human organism that contain $46$ chromosomes and carry out diverse physiological roles.

Germ cells

Human sex cells (sperm and ovum) that contain $23$ chromosomes each and unite to form a total of $46$ chromosomes.

Prokaryotes

Unicellular organisms, such as bacteria and archaea, that lack a nucleus and other membrane-bound organelles.

Eukaryotes

Organisms such as animals, plants, and fungi whose cells possess membrane-bound internal organelles, including a distinct nucleus.

Intracellular fluid (ICF)

The fluid compartment located inside of cells, which accounts for approximately $66\%$ of total body fluid.

Extracellular fluid (ECF)

All fluid situated outside of cells, representing approximately $33\%$ of total body fluid, which includes interstitial fluid and plasma.

Interstitial fluid (IF)

The watery extracellular fluid that directly bathes and surrounds cells, making up approximately $80\%$ of the extracellular fluid compartment.

Plasma

The liquid fraction of blood contained within blood vessels, accounting for approximately $20\%$ of the extracellular fluid compartment.

Plasma membrane

A selectively permeable phospholipid bilayer containing proteins and carbohydrates that defines cellular shape, regulates substance transport, and mediates cell-to-cell communication.

Phospholipid bilayer

A two-layered lipid membrane structure composed of outward-facing hydrophilic heads in contact with fluids and inward-facing hydrophobic tails shielded from water.

Hydrophilic heads

The water-attracting phosphate portions of phospholipid molecules that remain in contact with intracellular fluid and extracellular fluid.

Hydrophobic tails

The water-repelling fatty acid tails of phospholipid molecules directed inward within the bilayer interior away from watery environments.

Receptors

Membrane-bound protein molecules that bind chemical messengers like hormones, drugs, and neurotransmitters, or detect physical signals such as temperature and pressure, to alter cellular activity.

Diffusion

The passive net movement of solute particles down a concentration gradient from an area of higher solute concentration to an area of lower solute concentration until equilibrium is established.

Osmosis

The net movement of water molecules across a semi-permeable membrane down its concentration gradient, moving from a region of low solute (high water) concentration to high solute (low water) concentration.

Facilitated transport

Passive solute movement down a concentration gradient through transmembrane protein channels that alter their shape to control diffusion without energy consumption.

Active transport

Energy-dependent transport that pumps solutes up (against) their concentration gradient across a membrane, requiring adenosine triphosphate ($\text{ATP}$).

Pinocytosis

A cellular transport process in which the cell membrane invaginates and pinches off to create a small vesicle containing a droplet of extracellular fluid.

Aquaporins

Transmembrane protein channels that permit the passage of water molecules across the relatively water-impermeable lipid bilayer.

Cytoplasm

The thick, semi-transparent fluid medium composed of $75\%$ water, electrolytes, and proteins in which cellular organelles are suspended and primary metabolic reactions occur.

Organelles

Specialized membranous or non-membranous structures within the cell that perform dedicated roles in cellular growth, maintenance, repair, and control.

Nucleus

The largest, centrally located organelle, enclosed by a double-layered nuclear envelope, which contains the nucleolus, nucleoplasm, and genetic material ($\text{DNA}$ and $\text{RNA}$).

Rough endoplasmic reticulum (Rough ER)

A cytoplasmic network of channels studded with ribosomes on its outer surface that functions specifically in protein synthesis.

Smooth endoplasmic reticulum (Smooth ER)

A network of cytoplasmic channels devoid of ribosomes, responsible for synthesizing carbohydrates and lipids.

Golgi apparatus

An organelle composed of $4\text{--}8$ stacked, flattened sac-like channels located near the nucleus that packages products into vesicles for storage or cellular secretion.

Mitochondria

Double-membraned, sausage-shaped organelles known as the powerhouses of the cell where adenosine triphosphate ($\text{ATP}$) is produced.

Lysosomes

Membranous sac-like organelles filled with digestive enzymes that destroy bacteria and protect the cell, found in high numbers in white blood cells.

Centrioles

Spherical structures positioned near the nucleus composed of $9$ bundles of microtubules that assemble the spindle apparatus required for cell division.

Homeostasis

The maintenance of a stable, dynamic state of equilibrium within the body's internal environment essential for physiological functioning and sustaining life.

Negative feedback loop

A regulatory homeostatic mechanism that shuts off the original stimulus or reduces its intensity to return a variable to within normal limits.

Positive feedback loop

A feedback mechanism that reinforces and amplifies an initial stimulus to push a variable further toward a specific goal, observed in blood clotting and childbirth.

Afferent pathway

The transmission route (e.g., nerve impulses) that carries sensory information from a receptor to the control center.

Efferent pathway

The communication line that carries output signals from the control center to an effector to initiate a corrective response.

Effector

A bodily organ, cell, or tissue that executes the output instructions delivered along the efferent pathway to return a variable toward homeostasis.