Major Themes of Anatomy and Physiology Flashcards

Comprehensive practice flashcards covering homeostasis, cellular transport, histology, the integumentary system, bone tissue, and nervous/muscular physiology.

Homeostasis

A dynamic state of equilibrium where the nervous and endocrine systems are most important for maintaining stability.

Variable

The factor or event being regulated in a feedback system.

Receptor

A sensor that monitors the environment and responds to change.

Control Center

Determines the level or range (set point) at which a variable should be controlled.

Effector

Provides the means for the control center's response to a stimulus.

Negative feedback

A mechanism where the output shuts off the original effect of the stimulus or reduces its intensity, such as body temperature or blood pressure regulation.

Positive feedback

A mechanism where the output accelerates or increases the original effect of the stimulus, such as labor contractions, milk production, or scab formation.

Plasma Membrane

A lipid bilayer with proteins in a constantly changing fluid mosaic composed mainly of phospholipids and proteins.

Glycocalyx

A "sugar covering" at the cell surface made of lipids and proteins with attached carbohydrates, used for cell-cell and immune recognition.

Microvilli

Fingerlike extensions of the cell surface that increase surface area for absorption, with a core made of actin filaments.

Cilia

Hairlike processes that can be nonmotile (for sensory functions) or motile (to sweep material across a surface in one direction).

Pseudopods

Changing extensions of the cell surface that vary in shape or size, used for locomotion and capturing foreign particles.

Simple Diffusion

Molecules moving down their gradient without assistance, typically nonpolar lipid-soluble substances like $O_2$ and $CO_2$.

Osmosis

The movement of water across a membrane until hydrostatic and osmotic pressure equalize.

Tonicity

The ability of a solution to alter a cell’s water volume.

Hypertonic solution

A solution with a higher non-penetrating solute concentration than the cytosol, causing cells to lose water and shrink.

Hypotonic solution

A solution with a lower non-penetrating solute concentration than the cytosol, causing cells to gain water and burst.

Sodium-Potassium Pump

A primary active transport carrier ($Na^+-K^+$ ATPase) that removes sodium from and brings potassium into the cell using ATP.

Phagocytosis

A form of endocytosis known as "cell eating," involving the engulfing of large particles by pseudopods and macrophages.

Pinocytosis

A form of endocytosis known as "cell drinking," where the membrane caves in to take in droplets of extracellular fluid.

Epithelial tissue

Avascular sheets of closely adhering cells that form boundaries, protect, secrete, absorb, and filter.

Cartilage

A stiff connective tissue with a flexible matrix, containing chondrocytes trapped in lacunae.

Hyperplasia

Tissue growth through cell multiplication.

Hypertrophy

Tissue growth through the enlargement of preexisting cells, such as muscle growth.

Metaplasia

The development of a mature tissue type into another, such as when simple cuboidal tissue in the vagina changes to stratified squamous after puberty.

Apoptosis

Programmed cell death that occurs normally after cells have completed their function.

Stratum basale

The actively mitotic regeneration layer of the epidermis, containing stem cells and melanocytes.

Stratum corneum

The outermost layer of the epidermis, consisting of up to 3/4 of its thickness and made of dead, flat keratinized membranous sacs.

Osteoblasts

Bone-building cells that synthesize soft matrix and harden it by mineral deposition (osteogenesis).

Osteoclasts

Giant bone-resorbing or breaking cells that reside in resorption bays.

Appositional Growth

An increase in bone thickness that occurs throughout life via intramembranous ossification.

Resting Membrane Potential

The stable voltage across a cell membrane, typically around $-70\,mV$, created by the $Na^+/K^+$ pump and $K^+$ leak channels.

Action Potential

Rapid electrical signals produced by the opening/closing of voltage-gated ion channels, resulting in quick depolarization and repolarization.

All-or-none law

The principle that if a threshold is reached, a neuron fires to maximum voltage; if not reached, it does not fire at all.

Sarcomere

The functional contractile unit of a muscle fiber, measured from one Z disc to the next.

Dendrites

Tree-like extensions of a neuron that receive signals from other cells.

Oligodendrocytes

Neuroglia in the CNS that form myelin sheaths by wrapping arm-like processes around nerve fibers.

Saltatory Conduction

A type of signal propagation in myelinated axons where the signal "jumps" from node of Ranvier to node, making it faster.

GABA

The most common inhibitory neurotransmitter in the brain.

Hypothalamus

The major control center of the autonomic nervous system, essential for homeostasis, including thermoregulation and hormone secretion.