Anatomy and Physiology: Cell Biology, Membrane Transport, and Cellular Dynamics

Comprehensive question-and-answer flashcard set covering nursing anatomy and physiology fundamentals, including cell membrane transport, cellular organelles, genetic expression, mitotic/meiotic division, and physiological application scenarios.

gross anatomy

The study of body structures visible to the naked eye, such as dissecting a cadaver to examine muscles, bones, and organs.

microscopic anatomy

The study of structures too small to be seen without a microscope. Its two divisions are histology (the study of tissues) and cytology (the study of cells).

developmental anatomy (embryology)

The study of structural changes from fertilization to adulthood, with embryology focusing on early structural development before birth.

egional anatomy

The study of all structures in a specific body region, such as examining the bones, muscles, and nerves of the head and neck.

surface anatomy

The study of external body features and their structural relation to deeper tissues and organs.

comparative anatomy

The study of structural similarities and differences among different species.

systemic physiology

The study of the specific functional characteristics of entire organ systems.

pathophysiology

The study of how normal physiological processes are altered by disease or injury.

exercise physiology

The study of how physical activity affects body functions and structures.

neurophysiology

The study of the functional properties of the nervous system.

cardiovascular physiology

The study of the functions of the heart and blood vessels.

respiratory physiology

The study of the function of the lungs and respiratory airways.

six levels of structural organization

Chemical, Cellular, Tissue, Organ, Organ system, and Organismal levels.

three main structural components of a human cell

1. Plasma (cell) membrane, 2. Cytoplasm (cytosol and organelles), and 3. Nucleus (chromosomes and genes).

two main types of membrane proteins

Integral (transmembrane) proteins and peripheral proteins

function of cholesterol in the plasma membrane

Cholesterol serves to stabilize the membrane structure and reduce membrane fluidity.

Small nonpolar molecules ($\text{O}_2$, $\text{CO}_2$, $\text{N}_2$), small uncharged polar molecules (water, ethanol, small amounts of urea), and lipid-soluble hydrophobic molecules (fatty acids, steroids, vitamins A, D, E, K).

Which molecules can pass directly through the lipid bilayer by simple diffusion?

What constitutes an electrochemical gradient across a plasma membrane?

The combined effect of a concentration gradient (difference in solute concentration) and an electrical gradient (difference in ion charge) across the membrane.

What five factors influence the rate of simple diffusion?

1. Steepness of the concentration gradient, 2. Temperature, 3. Mass of the diffusing substance, 4. Surface area, and 5. Diffusion distance.

Why does carbon dioxide diffuses faster than oxygen across respiratory membranes?

Because carbon dioxide ($\text{CO}_2$) has a lower molecular mass than oxygen ($\text{O}_2$).

How does channel-mediated facilitated diffusion differ from carrier-mediated facilitated diffusion?

Channel-mediated diffusion moves small ions or water through a water-filled protein pore without shape changes, whereas carrier-mediated diffusion moves specific larger molecules via a protein that undergoes a conformational shape change.

What is the mechanism of action of local anesthetics like lidocaine?

Lidocaine crosses the nerve membrane and binds inside voltage-gated $\text{Na}^+$ channels, blocking $|\text{Na}^+$$ entry, preventing depolarization and action potential generation.

How does insulin facilitate glucose entry into muscle and adipose cells?

Insulin binds to cell receptors, triggering $\text{GLUT4}$ transporters to move to the cell surface, allowing glucose to enter down its concentration gradient via carrier-mediated facilitated diffusion.

What happens to a red blood cell placed in a hypotonic solution?

Water enters the cell down its osmotic gradient, causing the red blood cell to swell and potentially undergo hemolysis (bursting).

What happens to a red blood cell placed in a hypertonic solution?

Water moves out of the cell into the hypertonic environment, causing the cell to shrink and undergo crenation.

Why is hypertonic 3% NaCl solution administered to patients with cerebral edema?

The high salt concentration in the blood pulls excess water out of swollen brain cells into the vascular system, reducing brain swelling and intracranial pressure.

Why is hypotonic 0.45% NaCl solution given in hypernatremic dehydration?

It lowers blood sodium concentration and causes water to move from the intravascular space into dehydrated body cells, rehydrating them.

How does Digoxin increase cardiac contractile force via primary active transport inhibition?

Digoxin blocks the $\text{Na}^+/\text{K}^+\text{-ATPase}$ pump, causing $\text{Na}^+$ to build up inside cardiac cells. This slows the $\text{Na}^+/\text{Ca}^{2+}$ exchanger, leading to intracellular $\text{Ca}^{2+}$ accumulation and stronger heart contractions.

What ion movement ratio is driven by the $\text{Na}^+/\text{K}^+\text{-ATPase}$ pump per ATP consumed?

It pumps $3\,\text{Na}^+$ out of the cell and $2\,\text{K}^+$ into the cell against their concentration gradients.

How does administering insulin with glucose treat severe hyperkalemia?

Insulin indirectly stimulates the $\text{Na}^+/\text{K}^+\text{-ATPase}$ pump, forcing excess potassium ($\text{K}^+$) from the blood back into cells; glucose is co-administered to prevent hypoglycemia.

What is the structural difference between symporters and antiporters in secondary active transport?

Symporters move two substances across the membrane in the same direction, whereas antiporters move two substances in opposite directions.

How do SGLT2 inhibitors lower blood glucose in type 2 diabetes mellitus?

They block the sodium-glucose cotransporter 2 (SGLT2) in kidney proximal tubules, preventing glucose reabsorption and promoting urinary glucose excretion.

What are the six sequential steps of receptor-mediated endocytosis?

1. Binding, 2. Vesicle Formation, 3. Uncoating, 4. Fusion with Endosome, 5. Recycling of Receptors, 6. Degradation in Lysosome.

What genetic defect causes Familial Hypercholesterolemia?

Defective or missing LDL receptors, preventing proper receptor-mediated endocytosis of cholesterol and leading to elevated blood cholesterol levels.

What cellular process do neutrophils and macrophages use to engulf pathogens?

Phagocytosis, extending pseudopods to surround the particle and form a phagosome, which then fuses with a lysosome.

What is pinocytosis (bulk-phase endocytosis)?

A non-specific form of endocytosis where the cell membrane folds inward to drink or take in small droplets of extracellular fluid containing solutes.

What is transcytosis?

A transport process combining endocytosis and exocytosis to move a substance completely across a cell inside a vesicle without destroying it.

What are the three main components of the cytoskeleton?

1. Microfilaments (actin filaments), 2. Intermediate filaments (e.g., keratin), and 3. Microtubules (tubulin).

What structural microtubule arrangement is found inside cilia and flagella?

A "9 + 2" arrangement consisting of nine doublet microtubules surrounding a central pair of single microtubules.

What is the difference in function between free and bound ribosomes?

Free ribosomes synthesize proteins used inside the cytosol, while bound ribosomes (on the rough ER) synthesize proteins destined for cell membranes, organelles, or extracellular secretion.

What are the functional differences between Rough ER and Smooth ER?

Rough ER synthesizes and modifies proteins destined for membranes or secretion. Smooth ER synthesizes lipids, metabolizes carbohydrates, detoxifies drugs/toxins, and stores $\text{Ca}^{2+}$.

What are the roles of the cis face, medial cisternae, and trans face of the Golgi complex?

The cis face receives transport vesicles from the rough ER; medial cisternae modify proteins/lipids; the trans face sorts and packages molecules into vesicles for shipping.

What function do proteasomes perform within the cell?

Proteasomes are barrel-shaped protein complexes that degrade damaged, unneeded, or faulty cytosolic proteins tagged with ubiquitin.

What is transcription and where does it occur?

The process by which RNA polymerase uses a DNA template strand to synthesize messenger RNA (mRNA); it occurs inside the cell nucleus.

What is translation and where does it occur?

The process where ribosomes read mRNA codons in groups of three nucleotides to assemble amino acids into polypeptide chains; it occurs in the cytoplasm.

What are the specific start and stop codons in mRNA translation?

The start codon is AUG; the stop codons are UAA, UGA, and UAG.

What happens during the G1, S, and G2 phases of interphase?

G1 phase (8–10 hours): Cell growth and organelle replication. S phase (8 hours): DNA replication. G2 phase (4–6 hours): Further cell growth, protein synthesis, and completion of centrosome replication.

What events occur during prophase of mitosis?

Chromatin fibers condense into visible paired chromatids, the nucleolus and nuclear envelope disappear, and centrosomes move to opposite cell poles.

What occurs during anaphase of mitosis?

Centromeres split, separating sister chromatids which are pulled to opposite poles of the cell by mitotic spindle fibers.

What role does the tumor suppressor protein p53 play in cell division?

p53 controls and regulates cell cycle progression and cell division; its malfunction or mutation can lead to uncontrolled cell growth and cancer.

What are the key functional differences between Mitosis and Meiosis?

Mitosis involves 1 division, producing 2 identical diploid (2n) somatic cells for growth and repair. Meiosis involves 2 divisions, producing 4 unique haploid (n) gametes for sexual reproduction.

What two key mechanisms generate genetic variation during Meiosis I?

1. Crossing over (recombination) between homologous chromosomes during Prophase I, and 2. Independent assortment of homologous pairs during Metaphase I.

What free radical is produced by the Fenton reaction ($\text{H}_2\text{O}_2 + \text{Fe}^{2+}$) and causes direct DNA strand breaks?

The hydroxyl radical ($\bullet\text{OH}$).