Lecture Exam Questions and Answers: Endocrine, Blood, and Cardiovascular Physiology

Comprehensive vocabulary flashcards covering lecture review questions on the endocrine system, blood, hemodynamics, and cardiovascular physiology/ECG.

Norepinephrine

A signaling molecule that acts as both a neurotransmitter and a hormone.

GnRH Receptor Specificity

The reason Gonadotropin-Releasing Hormone targets the anterior pituitary rather than the posterior pituitary, as only anterior pituitary cells possess specific receptors for GnRH.

Down-regulation

A cellular mechanism where target cells decrease their total receptor count in response to excessive hormone levels, such as from a parathyroid tumor.

Interleukin-2 (IL-2)

A local paracrine hormone involved in immune cell signaling that is inhibited by anti-rejection transplant drugs.

Insulin (Oral Route Limitation)

A protein hormone that cannot be taken orally as a pill because digestive enzymes and saliva break down its protein structure.

Tyrosine

The amino acid precursor from which $T_3$, $T_4$, epinephrine, and norepinephrine are synthesized.

Water-Soluble Hormone Mechanism

Receptor signaling systems ($1^{\text{st}}$ and $2^{\text{nd}}$ messenger cascades) governed by the golden rule of never directly activating gene expression.

Thyroid Hormone ($T_3/T_4$)

A hormone that binds directly to receptors inside the mitochondria to alter cellular energy production.

First Messenger

Any water-soluble hormone that binds directly to extracellular receptors located on the cell surface plasma membrane.

Lipid-Soluble Hormones (Steroids)

The hormone class that bypasses cell surface second messenger systems and does not use adenylate cyclase.

Epinephrine (Acute Stress)

The hormone responsible for generating rapid signal amplification cascades during acute stress responses.

Resistance Phase (Stress Response)

A prolonged stress phase mediated by $\text{CRH} \rightarrow \text{ACTH} \rightarrow \text{Cortisol}$ that increases lipolysis and gluconeogenesis while suppressing inflammation and immune function.

Antidiuretic Hormone (ADH / Vasopressin)

A hormone that conserves water in the kidneys without directly affecting sodium levels.

Aldosterone

A mineralocorticoid hormone that stimulates renal sodium retention and potassium excretion.

ABO Blood Type Determination

Determined by inherited specific antigens present on the outer surface of erythrocytes (red blood cells).

Pulmonary Vein Anatomy

Vessels that transport oxygenated blood to the left atrium; zero pulmonary veins carry deoxygenated blood to the right atrium.

Prothrombinase Formation

The initial event that initiates the common pathway of blood coagulation.

Warfarin

An anticoagulant medication that inhibits clotting by blocking Vitamin K action within the liver.

Fibrinogen

A circulating plasma protein produced by the liver that is absent from platelet granules.

Albumin

A major plasma protein synthesized by the liver that generates Blood Colloid Osmotic Pressure (BCOP) to pull fluid back into capillaries and prevent edema.

Hepatic Portal Vein

A blood vessel delivering deoxygenated, nutrient-rich blood from the digestive organs to the liver.

Atrial Natriuretic Peptide (ANP)

The sole hormone responsible for directly decreasing systemic blood pressure.

Acetylcholine (ACh)

A parasympathetic neurotransmitter secreted by the vagus nerve that acts on the heart to decrease heart rate.

Vasomotor Center Innervation

The neural control mechanism of blood vessel diameter, regulated exclusively by sympathetic nerves without parasympathetic innervation.

Right Ventricular Systole

The phase of right ventricular contraction during which the tricuspid valve closes and the pulmonary semilunar valve opens.

Left Ventricular Systole

The phase of left ventricular contraction during which the bicuspid (mitral) valve closes and the aortic semilunar valve opens.

Heart Valves

Anatomical structures enforcing the unidirectional flow of blood; chordae tendineae attach exclusively to atrioventricular (AV) valves, not semilunar valves.

Left Ventricle Lumen

The cross-sectional structural shape of the left ventricular cavity, characterized as circular.

Cardiac Conduction Pathway

The five-step electrical sequence of cardiac conduction: $\text{SA Node} \rightarrow \text{AV Node} \rightarrow \text{AV Bundle (Bundle of His)} \rightarrow \text{Right \& Left Bundle Branches} \rightarrow \text{Purkinje Fibers}$.

AV Node Block / Damage

An electrical conduction defect diagnosed on an ECG when P waves appear without subsequent corresponding QRS complexes.

P Wave

The ECG deflection representing atrial depolarization, immediately after which atrial systole begins.

Prolonged P-Q (P-R) Interval

An ECG abnormality that indicates coronary artery disease.

S-T Segment (Plateau Phase)

The phase of the cardiac myocyte action potential where Calcium ($Ca^{2+}$) influx occurs from extracellular fluid and the sarcoplasmic reticulum while Potassium ($K^+$) outflow begins.

Sarcoplasmic Reticulum (SR)

The primary intracellular organelle providing the majority of Calcium ($Ca^{2+}$) required for cardiac muscle contraction.

Resting Cardiac Muscle Metabolism

The primary pathway utilized by resting cardiac myocytes for energy generation, which is the aerobic oxidation of fatty acids.

Left Ventricular Failure

Heart failure of the left ventricle causing pulmonary edema due to fluid backing up directly into the lungs.

Right Ventricular Failure

Heart failure of the right ventricle leading to peripheral and systemic edema.

Frank-Starling Law of the Heart

The principle stating that an increased stretch (preload) on cardiac muscle fibers yields greater contractile force, equalizing output between the ventricles.

Cardiac Reserve

The difference between maximal and resting cardiac output, typically measuring $15\,\text{L/min}$ in healthy individuals ($20\,\text{L/min}$ maximum exercise minus $5\,\text{L/min}$ resting).

Right Facial Arterial Pathway

The complete pathway from the heart to the right side of the face: $\text{Ascending Aorta} \rightarrow \text{Aortic Arch} \rightarrow \text{Brachiocephalic Trunk} \rightarrow \text{Right Common Carotid Artery} \rightarrow \text{External Carotid Artery} \rightarrow \text{Maxillary Artery}$.

External Surface of the Heart

Gross anatomical landmarks consisting of shallow anterior and posterior interventricular sulci, a deep coronary sulcus, and variable amounts of adipose tissue.