Pathophysiology Unit 2 | Chapter 2 (Porth 5th Edition)

Question 1

Protoplasm

Answer 1

Intracellular fluid composed of water, proteins, lipids, carbohydrates, and electrolytes; divided into karyoplasm (nucleus) and cytoplasm.

Question 2

Nucleus

Answer 2

Control center of the cell containing DNA and RNA; site of transcription and synthesis of mRNA, rRNA, and tRNA.

Question 3

Ribosomes

Answer 3

Cellular structures responsible for protein synthesis; composed of rRNA and proteins; found free in cytoplasm or attached to rough ER.

Question 4

Rough Endoplasmic Reticulum

Answer 4

ER studded with ribosomes; synthesizes proteins for organelles, membranes, or secretion (e.g., insulin, lysosomal enzymes).

Question 5

Smooth Endoplasmic Reticulum

Answer 5

ER without ribosomes; synthesizes lipids, metabolizes hormones, and stores glucose as glycogen in the liver.

Question 6

Golgi Complex

Answer 6

Modifies and packages proteins from the ER into vesicles for secretion, membrane incorporation, or lysosomal storage.

Question 7

Lysosomes

Answer 7

Digestive organelles containing acidic enzymes; break down cellular debris, pathogens, and worn-out organelles via autophagy or heterophagy.

Question 8

Peroxisomes

Answer 8

Organelles containing enzymes to degrade peroxides (e.g., hydrogen peroxide) and synthesize bile acids in liver cells.

Question 9

Proteasomes

Answer 9

Cytoplasmic and nuclear complexes that degrade misfolded or damaged proteins tagged with ubiquitin.

Question 10

Mitochondria

Answer 10

Powerhouse of the cell; site of aerobic respiration (citric acid cycle, electron transport chain) producing ATP; contains mtDNA.

Question 11

Cytoskeleton

Answer 11

Network of microtubules, microfilaments, and intermediate filaments maintaining cell shape, motility, and organelle transport.

Question 12

Microtubules

Answer 12

Hollow tubes of tubulin; involved in cell structure, intracellular transport, and formation of cilia/flagella; targeted by cancer drugs (e.g., vincristine).

Question 13

Microfilaments

Answer 13

Thin actin filaments involved in cell movement (e.g., muscle contraction, microvilli structure).

Question 14

Cell Membrane

Answer 14

Lipid bilayer with embedded proteins; regulates transport, contains receptors, and maintains electrochemical gradients.

Question 15

Autocrine Signaling

Answer 15

Cell releases chemical messengers that act on its own receptors (e.g., immune cells).

Question 16

Paracrine Signaling

Answer 16

Local signaling where chemicals act on nearby cells (e.g., neurotransmitters).

Question 17

Endocrine Signaling

Answer 17

Hormones released into bloodstream to act on distant target cells (e.g., insulin).

Question 18

G-Protein-Linked Receptors

Answer 18

Largest receptor family; use G-proteins to activate second messengers (e.g., cAMP) upon ligand binding.

Question 19

Ion Channel-Linked Receptors

Answer 19

Receptors that open ion channels upon ligand binding (e.g., acetylcholine in neuromuscular junctions).

Question 20

Enzyme-Linked Receptors

Answer 20

Receptors with intrinsic enzymatic activity (e.g., tyrosine kinases activated by growth factors).

Question 21

Cell Cycle Phases (G0

Answer 21

G1

Question 22

ATP

Answer 22

Adenosine triphosphate; energy currency of the cell with high-energy phosphate bonds; produced via glycolysis and oxidative phosphorylation.

Question 23

Glycolysis

Answer 23

Anaerobic breakdown of glucose into pyruvate in the cytoplasm; yields 2 ATP and NADH.

Question 24

Citric Acid Cycle (Krebs Cycle)

Answer 24

Mitochondrial pathway oxidizing acetyl-CoA to CO2; generates NADH, FADH2, and 2 ATP per glucose.

Question 25

Electron Transport Chain

Answer 25

Mitochondrial process using NADH/FADH2 to create proton gradient; produces 32-34 ATP via oxidative phosphorylation.

Question 26

Diffusion

Answer 26

Passive movement of substances down a concentration gradient (e.g., O2, CO2).

Question 27

Osmosis

Answer 27

Passive movement of water through aquaporins from low to high solute concentration.

Question 28

Facilitated Diffusion

Answer 28

Carrier-mediated transport of molecules (e.g., glucose) down a concentration gradient without energy.

Question 29

Active Transport

Answer 29

Energy-dependent movement against a gradient (e.g., Na+/K+ ATPase pump).

Question 30

Na+/K+ ATPase Pump

Answer 30

Primary active transporter moving 3 Na+ out and 2 K+ into the cell; maintains resting membrane potential.

Question 31

Endocytosis

Answer 31

Cellular uptake of materials via vesicles (phagocytosis for solids, pinocytosis for liquids, receptor-mediated for specific molecules).

Question 32

Exocytosis

Answer 32

Release of intracellular substances (e.g., hormones, neurotransmitters) via vesicle fusion with the cell membrane.

Question 33

Resting Membrane Potential (RMP)

Answer 33

-70 to -90 mV in neurons; maintained by K+ leakage and Na+/K+ pump; critical for electrical excitability.

Question 34

Depolarization

Answer 34

Reduction in membrane potential (inside becomes less negative) due to Na+ or Ca2+ influx.

Question 35

Hyperpolarization

Answer 35

Increase in membrane potential (inside becomes more negative) due to K+ efflux or Cl- influx.

Question 36

Action Potential

Answer 36

Rapid depolarization and repolarization in excitable cells (neurons, muscle) for signal transmission.

Question 37

Epithelial Tissue

Answer 37

Avascular tissue lining surfaces (e.g., skin, gut); classified by shape (squamous, cuboidal, columnar) and layers (simple, stratified).

Question 38

Basement Membrane

Answer 38

Extracellular matrix layer anchoring epithelial cells; composed of basal lamina and reticular fibers.

Question 39

Tight Junctions

Answer 39

Zonula occludens; seal adjacent epithelial cells to prevent leakage (e.g., intestinal barrier).

Question 40

Gap Junctions

Answer 40

Channels connecting cytoplasm of adjacent cells; allow ion/molecule exchange (e.g., cardiac muscle).

Question 41

Connective Tissue

Answer 41

Supports and connects structures; includes loose, dense, adipose, bone, cartilage, and blood.

Question 42

Skeletal Muscle

Answer 42

Striated, voluntary muscle attached to bones; contains sarcomeres, T-tubules, and sarcoplasmic reticulum for Ca2+ storage.

Question 43

Cardiac Muscle

Answer 43

Striated, involuntary heart muscle with intercalated discs and gap junctions for synchronized contraction.

Question 44

Smooth Muscle

Answer 44

Non-striated, involuntary muscle in hollow organs; uses calmodulin (not troponin) for Ca2+-mediated contraction.

Question 45

Neurons

Answer 45

Nerve cells with soma, dendrites, and axon; transmit signals via action potentials and synapses.

Question 46

Neuroglia

Answer 46

Supporting cells in nervous system (e.g., astrocytes, oligodendrocytes, Schwann cells for myelination).

Question 47

Collagen

Answer 47

Most abundant extracellular protein; provides tensile strength in tendons, skin, and bones.

Question 48

Elastin

Answer 48

Extracellular protein allowing tissue elasticity (e.g., aorta, lungs).

Question 49

Lysosomal Storage Disorders

Answer 49

Diseases caused by deficient lysosomal enzymes (e.g., Tay-Sachs due to hexosaminidase A deficiency).

Question 50

Cystic Fibrosis

Answer 50

Genetic defect in CFTR chloride channel; causes thick mucus in lungs and pancreas.

Question 51

Primary Ciliary Dyskinesia

Answer 51

Immotile cilia syndrome; leads to chronic respiratory infections and infertility.