Video Notes: Functional Organization of the Human Body and Cell Biology (Vocabulary Flashcards)

A vocabulary set covering organizational levels, cell membranes, organelles, and homeostatic regulation drawn from the lecture notes.

Homeostasis

Maintenance of a relatively stable internal environment in the face of changing external conditions.

Internal environment

Extracellular fluid compartment where body cells live (the body's 'internal milieu').

External environment

The world outside the body; conditions that can affect internal states.

Negative feedback

Regulatory loop that minimizes deviations from a set point by reducing the error signal.

Positive feedback

Regulatory loop that amplifies a change rather than reducing it; often used in non-homeostatic processes.

Set point

Normal range or value around which a variable is regulated; not necessarily a single fixed point.

Sensor

Receptor that detects changes in a regulated variable.

Control center

Structure that interprets sensor input and directs an appropriate response.

Effector

Organ or cell that executes a response to bring the variable toward its set point.

Interdependence

Idea that body systems must work together (e.g., cardiovascular with respiratory) to sustain life.

Organ system

Group of organs functioning together to perform a major physiological task.

Organ

Structure composed of different tissues that performs a specific function.

Tissue

Group of similar cells performing a common function.

Cell

Smallest unit of life that can carry out all life’s activities.

Plasma membrane

Phospholipid bilayer surrounding the cell that regulates entry/exit of substances.

Fluid mosaic model

Concept describing the plasma membrane as a dynamic mix of lipids and proteins within a fluid framework.

Phospholipid bilayer

Two-layer arrangement of phospholipids forming the basic membrane structure; hydrophilic heads outward, hydrophobic tails inward.

Hydrophilic head

Polar, water-attracting region of a phospholipid.

Hydrophobic tail

Nonpolar, water-repelling region of a phospholipid.

Integral protein

Membrane protein that spans the bilayer and may form channels or transporters.

Peripheral protein

Membrane protein attached to the membrane surface, not spanning the bilayer.

Glycoprotein

Protein with carbohydrate chains attached; involved in cell recognition and signaling.

Glycolipid

Lipid with carbohydrate chains; contributes to the glycocalyx.

Glycocalyx

Carbohydrate-rich coating on the cell surface formed by glycoproteins and glycolipids.

Cholesterol (in membrane)

Sterol in the lipid bilayer that modulates membrane fluidity and stability.

Transport protein

Protein that facilitates movement of substances across the membrane (carriers or channels).

Channel protein

Transmembrane protein forming a pore for ions or molecules to pass.

Receptor

Membrane protein that binds signaling molecules and triggers a cellular response.

Enzyme (membrane-bound)

Protein in the membrane that catalyzes reactions at the membrane surface.

Endocytosis

Process by which cells internalize material via vesicles from the plasma membrane.

Exocytosis

Process by which cells secrete materials through vesicle fusion with the plasma membrane.

Endomembrane system

Interconnected membranes (ER, Golgi, lysosomes, vesicles) that synthesize, modify, package, and transport proteins and lipids.

Rough endoplasmic reticulum (RER)

ER studded with ribosomes; site of protein synthesis and processing for membranes, secretion, or lysosomes.

Smooth endoplasmic reticulum (SER)

ER lacking ribosomes; lipid synthesis, detoxification, and calcium storage.

Golgi apparatus

Stacks of flattened membranes that modify, sort, and package proteins and lipids for secretion or delivery.

Lysosome

Organelle containing hydrolytic enzymes for intracellular digestion.

Ribosome

Ribonucleoprotein particle that synthesizes proteins; composed of RNA and proteins; free and bound forms.

Nucleus

Membrane-bound organelle containing the cell’s genetic material; control center of the cell.

Nucleolus

Nuclear region where ribosomal RNA synthesis and ribosome assembly occur.

Chromatin

DNA-protein complex in the nucleus; becomes chromosomes during cell division.

Nuclear envelope

Double membrane surrounding the nucleus with nuclear pores.

Nuclear pore

Channels in the nuclear envelope that regulate transport between nucleus and cytoplasm.

Mitochondrion

Powerhouse of the cell; ATP production via oxidative phosphorylation; contains its own DNA.

Cristae

Folds of the inner mitochondrial membrane that increase surface area for respiration.

Matrix

Fluid inside the inner mitochondrial membrane containing citric acid cycle enzymes.

ATP synthase

Enzyme complex in the inner mitochondrial membrane that makes ATP using a proton gradient.

Mitochondrial DNA

Circular DNA within mitochondria encoding a subset of respiratory chain proteins.

Peroxisome

Organelle with enzymes for detoxification and fatty acid oxidation.

Cytoskeleton

Network of protein filaments that gives the cell its shape and aids movement.

Microtubules

Hollow tubes of the cytoskeleton involved in transport and cell division.

Microfilaments

Actin filaments involved in cell shape changes and muscle contraction.

Vesicle

Small membrane-bound sac used to transport materials within the cell.

Rough vs. Smooth Endoplasmic Reticulum

RER: protein synthesis and processing; SER: lipid synthesis and detoxification.

Protein synthesis

Process by which cells build proteins based on mRNA templates; occurs at ribosomes.

Glycosylation

Addition of carbohydrate groups to proteins or lipids within the ER and Golgi.

Mitochondrial DNA

Circular DNA within mitochondria encoding some respiratory chain proteins.

Endomembrane system (summary)

Network including ER, Golgi, lysosomes, and vesicles that coordinates synthesis, modification, and transport of cellular products.

Negative feedback gain

Degree to which a control system reduces error; higher gain means tighter regulation.

Circadian rhythm

Intrinsic 24-hour biological clock regulating cycles like temperature and hormone release.

Acidosis

Blood pH below 7.35.

Alkalosis

Blood pH above 7.45.

Carotid body

Chemosensor that detects arterial PO2 and helps regulate respiration.

Aortic body

Chemosensor that detects arterial PO2 and contributes to respiratory regulation.

Glucagon

Pancreatic hormone (alpha cells) that raises blood glucose during hypoglycemia.

Insulin

Pancreatic hormone (beta cells) that promotes glucose uptake and storage.

Hypoglycemia

Low blood glucose; triggers glucagon release to restore glycemia.