Nerves, Signals & Control
Which region of the spinal cord is gray vs. white matter, and what’s the main role of each?
Gray = inner → processing & synapses; White = outer → myelinated axons for signal transmission.
Trace blood through the heart starting at the right atrium.
RA → RV → pulmonary artery → lungs → pulmonary vein → LA → LV → aorta.
Define first-pass metabolism and where it occurs.
Drug metabolized by liver (before systemic circulation).
What is homeostasis, and which two systems mainly control it?
Stable internal conditions; nervous & endocrine systems coordinate feedback loops.
Which agency regulates animal drugs and feed additives?
FDA (Center for Veterinary Medicine).
Which direction do afferent and efferent nerves carry information?
Afferent = sensory → CNS; Efferent = motor → muscles/glands.
Why is the left ventricle thicker than the right?
It must generate higher pressure to pump to systemic circulation.
Which route completely bypasses first-pass metabolism?
Intravenous (IV).
Name the three hormones that regulate blood calcium.
PTH ↑Ca²⁺; Calcitonin ↓Ca²⁺; Vitamin D ↑absorption from gut.
Which U.S. agency focuses on livestock health and food safety?
USDA.
Why do myelinated axons conduct faster than unmyelinated ones?
Action potentials “jump” node-to-node (saltatory conduction).
What is the job of the valves, and what happens if one fails?
Keep blood unidirectional; failure → backflow → murmur.
Combine and compare first-order vs. zero-order kinetics.
First-order = constant fraction removed; Zero-order = constant amount removed (enzymes saturated).
Signs of hypocalcemia vs hypercalcemia?
Hypo → tremors/tetany; Hyper → weakness/lethargy.
Which organization leads zoonotic disease tracking and One Health?
CDC.
Outline the path of a simple reflex arc using spinal cord organization.
Receptor → afferent (dorsal root) → interneuron (gray matter) → efferent (ventral root) → effector muscle.
Explain how baroreceptors and the nervous system correct a sudden drop in blood pressure.
↓BP → ↓baroreceptor firing → ↑sympathetic tone → ↑HR & vasoconstriction.
Why are cats more prone to drug toxicity than dogs?
Limited glucuronidation → slower metabolism → toxic metabolite accumulation (e.g., acetaminophen).
What happens to excitable cells during hyperkalemia?
Resting membrane potential depolarized → arrhythmias / cardiac arrest risk.
Match each: FDA = ___, USDA = ___, CDC = ___, OIE/WOAH = ___.
FDA – drug safety; USDA – livestock/food; CDC – public health; OIE – international standards.
How does the autonomic nervous system maintain homeostasis between rest and stress?
Parasympathetic (“rest-digest”) vs Sympathetic (“fight-flight”) balance organ activity through opposing signals.
During exercise, how do the cardiac, respiratory, and renal systems coordinate?
↑HR & contractility → ↑O₂ delivery; ↑resp rate → CO₂ removal; kidneys retain fluid to maintain volume.
Explain how lipid solubility and protein binding affect drug duration.
Lipophilic & protein-bound drugs stay longer in body → slower elimination & longer half-life.
How can renal failure alter both electrolytes and acid-base status?
↓excretion of K⁺ & H⁺ → hyperkalemia + metabolic acidosis → neuromuscular and cardiac effects.
Why must veterinarians understand agency roles for reportable diseases?
Ensures proper notification, legal compliance, and public health coordination.