Exam 1 Study Guide - Vocabulary Flashcards

Vocabulary-style flashcards covering definitions and key terms from the lecture notes on homeostasis, diffusion, transport, cell biology, epithelial and connective tissues, bone physiology, and protein synthesis.

Homeostasis

Maintenance of a relatively stable internal environment through feedback mechanisms involving stimulus, receptor, control center, and effector.

Stimulus

A change in a variable that initiates a feedback response.

Receptor

Sensor that detects a stimulus and sends information to the control center.

Control center

Processes information from receptors and determines the appropriate response to maintain homeostasis.

Effector

An organ or cell that carries out the response to restore homeostasis.

Negative feedback

A response that counteracts the initial change to return the variable toward its set point.

Membrane proteins

Proteins in the cell membrane with roles beyond diffusion and active transport, including channels, carriers, receptors, enzymes, and anchors.

Simple diffusion

Passive movement of small, nonpolar molecules down their concentration gradient through the lipid bilayer.

Osmosis

Diffusion of water across a semipermeable membrane down its concentration gradient.

Facilitated diffusion

Passive transport of substances via membrane proteins down a concentration gradient.

Diffusion through lipid bilayer

Movement of nonpolar, lipid-soluble molecules directly through the lipid portion of the membrane.

Isotonic

Solutions with the same solute concentration as the cell interior; no net water movement.

Hypertonic

Higher solute outside the cell; water leaves and the cell shrinks.

Hypotonic

Lower solute outside the cell; water enters and the cell swells.

Water movement direction

Water moves to balance solute concentrations; direction depends on relative solute levels across the membrane.

Protein channels

Integral membrane proteins that form pores for ions or molecules to diffuse through.

Protein carriers

Membrane proteins that bind solutes and undergo conformational changes to shuttle them across.

Similarities between simple and facilitated diffusion

Both are passive and rely on a concentration gradient; no direct energy input.

Differences between simple and facilitated diffusion

Simple diffusion uses the lipid bilayer; facilitated diffusion requires membrane proteins (channels or carriers).

Channel-mediated diffusion

Diffusion through a channel protein selective for certain ions or molecules.

Carrier-mediated diffusion

Diffusion via carrier proteins that change shape to move solutes.

Primary active transport

Active transport that uses ATP directly to pump substances against their gradient.

Secondary active transport

Active transport that uses energy from an ion gradient (usually Na+) to move another solute against its gradient.

Sodium-potassium pump

Na+/K+ ATPase; membrane pump that uses ATP to maintain Na+ and K+ gradients.

Antiport

Antiport (counter-transport): two substances move in opposite directions via the same transporter.

Symport

Symport (co-transport): two substances move in the same direction via the same transporter.

Endocytosis

Process by which cells take in materials via vesicle formation.

Exocytosis

Process by which cells secrete substances via vesicles fusing with the plasma membrane.

Phagocytosis

Endocytosis of large particles or microorganisms; cell eating.

Pinocytosis

Endocytosis of extracellular fluid and dissolved solutes; cell drinking.

Sodium and potassium concentrations

Na+ is higher outside the cell; K+ is higher inside the cell; contributes to membrane potential.

Resting membrane potential

Electrical potential difference across the cell membrane at rest, typically negative inside.

Transcription

Synthesis of RNA from a DNA template, occurring in the nucleus.

Translation

Synthesis of a polypeptide at the ribosome using mRNA as a template; tRNA brings amino acids.

Codon

Three-nucleotide sequence in mRNA that codes for a specific amino acid.

Anticodon

Three-nucleotide sequence on tRNA that pairs with the mRNA codon.

mRNA

Messenger RNA; carries genetic information from DNA to ribosomes for protein synthesis.

rRNA

Ribosomal RNA; structural and catalytic component of ribosomes.

tRNA

Transfer RNA; delivers specific amino acids to the growing polypeptide chain and contains anticodons.

Ribosome

Ribonucleoprotein complex that translates mRNA into protein.

Rough endoplasmic reticulum

ER studded with ribosomes; site of synthesis for proteins destined for secretion or membranes.

Golgi apparatus

Organelle that processes, sorts, and ships proteins to final destinations via vesicles.

Exocytosis steps

Vesicles fuse with the plasma membrane and release contents outside the cell.

Epithelial tissue

Tissue that lines surfaces and forms glands; tightly packed cells with minimal extracellular matrix.

Epithelium

Another term for epithelial tissue.

Endocardium

Inner lining of the heart chambers; part of the heart’s endothelial layer.

Endothelium

Thin squamous cell layer lining blood and lymphatic vessels.

Visceral pericardium

Innermost layer of the pericardium that covers the heart (epicardium).

Parietal pericardium

Outer layer of the pericardium lining the pericardial cavity.

Pleura

Membranes surrounding the lungs; visceral pleura covers the lungs and parietal pleura lines the chest wall.

Peritoneum

Membrane lining the abdominal cavity and covering abdominal organs; visceral and parietal layers.

Glandular epithelium

Epithelium that forms glands; secretions can be exocrine (ducts) or endocrine (blood).

Exocrine vs endocrine secretion

Exocrine glands secrete to ducts or surfaces; endocrine glands secrete hormones into the bloodstream.

Adipocytes

Fat-storing cells in adipose tissue that store triglycerides.

Subcutaneous fat

Adipose tissue located beneath the skin.

Visceral fat

Adipose tissue surrounding internal organs in the body cavity.

Ground substance

Noncellular, gel-like component of connective tissue ECM surrounding cells and fibers.

Fibers

Protein fibers in connective tissue (collagen, elastic, reticular) that provide structure.

Lacunae

Small cavities within bone or cartilage that house osteocytes or chondrocytes.

Cartilage types

Hyaline, elastic, and fibrocartilage with different matrix and fiber compositions.

Bone cell types

Osteoblasts (form bone), osteocytes (maintain bone), osteoclasts (resorb bone).

Bone remodeling

Ongoing process of bone resorption and formation to replace old bone and adapt to stress.

Blood calcium and bone activity

Changes in blood Ca2+ levels influence bone remodeling by modulating osteoblast/osteoclast activity.

Stimulus for osteoblasts/osteoclasts

Alterations in blood calcium levels trigger coordinated activity of bone-forming and bone-resorbing cells.

Control of bone remodeling

Regulated by signaling among bone cells and mechanical stress; hormonal control is not the focus here.