High-Yield Final Flashcards

What is homeostasis?

Maintenance of internal stability.

Components of homeostasis?

Sensor, controller, output signal.

What is negative feedback?

Response that reduces the original signal.

Why do polar molecules need transporters?

They cannot cross the hydrophobic lipid bilayer.

What determines osmotic water movement?

Total solute load (osmolarity).

Three properties of carrier transport?

Specificity, competition, saturation.

What does the Na⁺ K⁺ ATPase pump move?

Three Na⁺ out and two K⁺ in.

Secondary active transport uses what?

Energy stored in an ion gradient.

What does SGLT transport?

Na⁺ and glucose into the cell.

What does GLUT transport?

Glucose by facilitated diffusion.

Gap junctions allow what?

Direct ion flow between cells.

Lipophilic ligands bind to what?

Intracellular receptors.

Lipophobic ligands bind to what?

Membrane receptors.

Fastest signaling pathway?

Receptor channel.

Four membrane receptor types?

Channel, GPCR, enzyme linked, integrin linked.

Why is resting membrane potential negative?

K⁺ leak, trapped anions, Na⁺ K⁺ pump.

Ion with highest permeability at rest?

K⁺.

Increased Na⁺ permeability causes what?

Depolarization.

Increased K⁺ permeability causes what?

Hyperpolarization.

Threshold value?

About -55 mV.

What channels open at threshold?

Voltage-gated Na⁺ channels.

Are action potentials graded or all-or-none?

All-or-none.

Do action potentials decrease over distance?

No.

Cause of depolarization?

Na⁺ influx.

Cause of repolarization?

K⁺ efflux.

Absolute refractory period caused by what?

Na⁺ channel inactivation.

Relative refractory period means what?

Some Na⁺ channels reset while K⁺ channels remain open.

Saltatory conduction means what?

APs jump between nodes of Ranvier.

How does myelin increase conduction speed?

Reduces ion leakage.

Hypokalemia effect?

Hyperpolarization and decreased excitability.

Hyperkalemia effect?

Depolarization and increased excitability.

EPSPs are caused by what movement?

Na⁺ entering the cell.

IPSPs are caused by what movement?

Cl⁻ entering or K⁺ leaving.

Fast synaptic potentials are mediated by what?

Ionotropic receptors.

Slow synaptic potentials are mediated by what?

GPCRs.

What is spatial summation?

Multiple presynaptic inputs combining.

What is temporal summation?

One neuron firing repeatedly.

GABA-A receptor type?

Ionotropic Cl⁻ channel.

GABA-A activation causes what?

Hyperpolarization.

Nicotinic ACh receptor type?

Ionotropic Na⁺ K⁺ channel.

Nicotinic receptor activation causes what?

Depolarization.

Muscarinic receptor type?

GPCR.

Alpha-1 receptor effect?

Increased intracellular Ca²⁺ and contraction.

Alpha-2 receptor effect?

Decreased Ca²⁺ and inhibition.

Beta-1 receptor effect?

Increased cardiac contraction.

Beta-2 receptor effect?

Bronchodilation.

T-tubules are part of what?

The sarcolemma.

Each myosin head binds what?

Actin and ATP.

What is unfused tetanus?

Repeated twitches with partial relaxation.

Energy system for about 10 seconds of intense activity?

Phosphocreatine system.

Characteristics of slow oxidative fibers?

Many mitochondria, high capillary density, fatigue resistant.

Ca²⁺ binds what in skeletal muscle?

Troponin.

What triggers the power stroke?

Ca²⁺ binding to troponin.

What releases myosin from actin?

ATP binding to myosin.

What determines muscle tension?

Overlap of thick and thin filaments.

Role of the DHP receptor?

Opens the ryanodine receptor.

What ends skeletal muscle contraction?

Ca²⁺ ATPase pumping Ca²⁺ into the SR.

Ca²⁺ binds what?

Calmodulin.

MLCK activated by what?

Ca²⁺ calmodulin.

Smooth muscle relaxation occurs when?

Myosin phosphatase removes phosphate from myosin.

Why is the cardiac AP long?

Ca²⁺ entry during the plateau.

Why no tetanus in cardiac muscle?

Long refractory period.

What depolarizes pacemaker cells?

Ca²⁺ influx.

Sympathetic effect on heart rate?

Increases.

Parasympathetic effect on heart rate?

Decreases.

Stroke volume equation?

EDV - ESV.

Cardiac output equation?

Heart rate imes stroke volume.

Frank-Starling Law states what?

Increased EDV increases stroke volume.

P wave represents what?

Atrial depolarization.

QRS complex represents what?

Ventricular depolarization.

T wave represents what?

Ventricular repolarization.

Boyle’s Law states what?

Pressure is inversely proportional to volume.

Major determinant of airway resistance?

Radius.

Function of surfactant?

Reduces surface tension.

Law of Laplace meaning?

Pressure is proportional to surface tension and inversely proportional to radius.

Function of Type I alveolar cells?

Gas exchange.

Function of Type II alveolar cells?

Surfactant secretion.

Anatomical dead space volume?

About 150 mL.

Primary regulator of ventilation?

CO₂.

Hyperventilation causes what?

Decreased CO₂ and increased pH.

Hypoventilation causes what?

Increased CO₂ and decreased pH.

What shifts the O₂-Hb curve to the right?

Increased CO₂, increased H⁺, increased temperature.

Major form of CO₂ transport?

Bicarbonate.

Water always reabsorbed where?

Proximal tubule and descending limb.

Water never reabsorbed where?

Ascending limb.

NKCC transporter location?

Apical side of the ascending limb.

ADH stimulated by what?

Increased osmolarity or decreased blood volume.

ADH causes what?

Increased water reabsorption through aquaporins.

Aldosterone stimulated by what?

Low Na⁺, high K⁺, or angiotensin II.

Aldosterone causes what?

Increased Na⁺ reabsorption and increased K⁺ secretion.

Afferent arteriole constriction does what to GFR?

Decreases GFR.

Efferent arteriole constriction does what to GFR?

Increases GFR initially.

HCl is produced by which cells?

Parietal cells.

Enzyme that produces H⁺ in parietal cells?

Carbonic anhydrase.

Gastrin stimulates what?

Acid secretion.

Most digestion occurs where?

Small intestine.

What neutralizes stomach acid?

Pancreatic bicarbonate.

What emulsifies fats?

Bile salts.

Bile salts reabsorbed where?

Ileum.

Function of microvilli?

Increase surface area.