Lecture 1: Introduction to Physiology, The Cell, and Homeostasis

Vocabulary flashcards covering key terms and concepts from Lecture 1: The Cell, Physiology, and Body Fluid Homeostasis.

Physiology

The study of the functions and mechanisms that operate within living systems; integrates biochemistry, anatomy, physics, and cell biology.

Anatomy vs Physiology

Anatomy focuses on structure; physiology focuses on function and interactions; pathophysiology studies what happens when processes fail.

Integrative Science in Physiology

Physiology draws on multiple disciplines (biochemistry, anatomy, physics, cell biology) to explain how systems work.

Central Dogma

Information flows from DNA to RNA to protein; reverse transcription allows RNA to DNA in some contexts.

Nucleus

Cellular organelle that houses DNA and is the site of transcription; surrounded by a nuclear envelope with pores.

Mitochondria

Powerhouse of the cell; site of aerobic respiration and ATP production via oxidative phosphorylation; contains maternal DNA.

Electron Transport Chain (ETC)

Series of protein complexes that transfer electrons to O2, pumping protons to generate a proton gradient for ATP synthesis.

NADH Dehydrogenase (Complex I)

Transfers electrons from NADH to CoQ and pumps protons across the inner mitochondrial membrane.

Succinate Dehydrogenase (Complex II)

Transfers electrons from FADH2 to CoQ; does not pump protons.

Cytochrome bc1 complex (Complex III)

Transfers electrons to cytochrome c and pumps protons across the membrane.

Cytochrome c oxidase (Complex IV)

Transfers electrons to O2 to form water; pumps protons.

ATP Synthase (Complex V)

Uses the proton gradient to synthesize ATP from ADP and Pi.

Oxidative Phosphorylation

ATP production driven by the proton motive force across the inner mitochondrial membrane.

Rough Endoplasmic Reticulum (RER)

ER studded with ribosomes; synthesizes proteins for export or membrane insertion.

Smooth Endoplasmic Reticulum (SER)

ER lacking ribosomes; synthesizes lipids/steroids and detoxifies drugs; rich in cytochrome P450 activity.

Golgi Apparatus

Modifies, sorts, and packages proteins for secretion; produces lysosomes and tags proteins for lysosomes (M6P).

Lysosomes

Digest cellular waste and engulfed material; defects cause lysosomal storage diseases.

Peroxisomes

Beta-oxidation of very long-chain fatty acids; detoxifies hydrogen peroxide; essential for lipid metabolism.

Tay-Sachs disease

Hexosaminidase A deficiency; GM2 ganglioside accumulation; neurodegeneration and cherry-red macula.

Zellweger syndrome

Peroxisomal biogenesis defect (PEX gene mutations); multi-system disease from loss of peroxisomes.

Kartagener syndrome

Ciliary dynein arm defect causing immotile cilia; chronic respiratory infections, infertility, situs inversus.

Cytoskeleton

Structural network of microtubules, microfilaments, and intermediate filaments; supports cell shape and movement.

Osmolarity

Number of solute particles per liter of solution (mOsm/L).

Tonicity

Ability of a solution to cause water movement across a semipermeable membrane.

Isotonic solution

No net water movement across cell membranes (e.g., 0.9% NaCl).

Hypotonic solution

Causes water to move into cells; cells swell.

Hypertonic solution

Causes water to move out of cells; cells shrink.

Starling forces

Forces governing fluid exchange across capillaries: capillary hydrostatic pressure, interstitial hydrostatic pressure, capillary oncotic pressure, and interstitial oncotic pressure.

Net filtration pressure

NetFiltration = (Pc − Pi) − (πc − πi); positive=filtration, negative=reabsorption.

Edema

Excess interstitial fluid from filtration exceeding reabsorption; causes include low albumin, high capillary pressure, and increased permeability.

IV fluids: isotonic

0.9% NaCl; expands extracellular fluid (plasma and interstitial) with no net cellular water shift.

IV fluids: hypotonic

0.45% NaCl or D5W; shifts water into cells; may worsen cerebral edema.

IV fluids: hypertonic

3% NaCl; draws water out of cells into the extracellular space; used for severe hyponatremia or cerebral edema.

ADH (vasopressin)

Hormone from the posterior pituitary; increases water reabsorption in kidneys via aquaporins.

Aldosterone

Mineralocorticoid from the adrenal cortex; increases Na+ and water reabsorption; promotes K+ excretion.

ANP

Atrial natriuretic peptide; promotes Na+ and water excretion, reducing blood volume.

RAAS

Renin-angiotensin-aldosterone system; kidney detects low BP/volume and raises volume via vasoconstriction and aldosterone/ADH.

Progeria (Hutchinson-Gilford)

Defective lamin A causing premature aging and cardiovascular risk.

I-cell disease

Golgi defect causing failure to add mannose-6-phosphate to lysosomal enzymes; enzymes secreted instead; growth delay.

Mitochondrial diseases

Mutations in mitochondrial DNA or related genes; maternal inheritance; includes MELAS, Leigh, LHON.

LHON

Leber’s Hereditary Optic Neuropathy; mitochondrial complex I mutation causing acute painless loss of central vision.