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Anatomy & Physiology: Endocrine System, Blood, and Cardiovascular System Study Guide

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  • What are hormones?

    Hormones are chemical messengers secreted by endocrine glands that regulate various body functions by acting on target cells.

  • Define endocrinology.

    Endocrinology is the study of hormones, the endocrine glands that produce them, and their effects on the body.

  • What are target cells?

    Target cells are cells that have specific receptors for a hormone and respond to its presence.

  • List major processes controlled by hormones.

    Hormones control growth, metabolism, reproduction, fluid and electrolyte balance, and stress responses.

  • Compare exocrine and endocrine glands.

    Exocrine glands secrete substances through ducts to body surfaces or cavities; endocrine glands release hormones directly into the bloodstream. Five major endocrine glands: pituitary, thyroid, parathyroid, adrenal, and pineal.

  • What is the hypothalamus role in the endocrine system?

    The hypothalamus is a neuroendocrine organ that links the nervous and endocrine systems by producing hormones that regulate the pituitary gland.

  • Compare autocrines and paracrines.

    Autocrines act on the same cell that secretes them; paracrines act on nearby cells without entering the bloodstream.

  • List mechanisms of hormone action.

    Hormones alter membrane permeability, stimulate protein synthesis, activate/deactivate enzymes, induce secretion, and stimulate mitosis.

  • Define humoral stimulus with example.

    Humoral stimulus triggers hormone release in response to changing blood levels of ions or nutrients, e.g., low blood calcium stimulates parathyroid hormone release.

  • Define neural stimulus with example.

    Neural stimulus involves nerve fibers stimulating hormone release, e.g., sympathetic nervous system triggers adrenal medulla to release epinephrine.

  • Define hormonal stimulus with example.

    Hormonal stimulus occurs when hormones stimulate other endocrine glands to release hormones, e.g., hypothalamic hormones stimulate the anterior pituitary.

  • Explain up-regulation vs down-regulation.

    Up-regulation: target cells increase receptors due to low hormone levels. Down-regulation: target cells decrease receptors after prolonged high hormone exposure.

  • What is a hormone's half-life?

    The half-life is the time it takes for half the hormone to be removed from the blood.

  • Define permissiveness in hormone interaction.

    Permissiveness occurs when one hormone enhances the target organ's response to a second hormone.

  • Define synergism in hormone interaction.

    Synergism is when two hormones produce the same effect and their combined effect is greater than the sum of individual effects.

  • Define antagonism in hormone interaction.

    Antagonism occurs when one hormone opposes the action of another.

  • Name hormones produced by the adrenal cortex.

    The adrenal cortex produces mineralocorticoids, glucocorticoids, and androgens.

  • What hormones does the adrenal medulla synthesize?

    The adrenal medulla synthesizes epinephrine and norepinephrine.

  • Roles of glucagon and insulin.

    Glucagon raises blood glucose by stimulating glycogen breakdown; insulin lowers blood glucose by promoting uptake and storage.

  • How does insulin lower blood glucose?

    Insulin lowers blood glucose by stimulating glucose uptake by cells, promoting glycogen formation, and inhibiting glucose release by the liver.

  • Define blood and its functions.

    Blood is a connective tissue that transports nutrients, gases, wastes, hormones, and helps regulate body temperature and immunity.

  • What are formed elements in blood?

    Formed elements include erythrocytes (red blood cells), leukocytes (white blood cells), and platelets (cell fragments).

  • Describe erythrocytes.

    Erythrocytes are biconcave, lack nucleus and organelles, and transport oxygen and carbon dioxide.

  • What is hematopoiesis?

    Hematopoiesis is the process of blood cell formation occurring in red bone marrow.

  • Define anemia and polycythemia.

    Anemia is a deficiency of red blood cells or hemoglobin; polycythemia is an excess of red blood cells.

  • What are leukocytes and their major categories?

    Leukocytes are white blood cells involved in immunity; major categories are granulocytes (neutrophils, eosinophils, basophils) and agranulocytes (lymphocytes, monocytes).

  • Define hemostasis.

    Hemostasis is the process that stops bleeding through vascular spasm, platelet plug formation, and coagulation.

  • Difference between whole blood and packed red blood cell transfusion.

    Whole blood transfusion replaces blood volume and cells; packed red blood cells transfusion replaces only red blood cells.

  • What determines ABO blood groups genetically?

    ABO blood groups are determined by alleles of the I gene encoding enzymes that add specific sugar antigens to red blood cells.

  • Define agglutinogens and agglutinins.

    Agglutinogens are antigens on red blood cells; agglutinins are antibodies in plasma that react against foreign agglutinogens.

  • Describe the pulmonary vs systemic circuit.

    The pulmonary circuit carries blood between the heart and lungs; the systemic circuit carries blood between the heart and the rest of the body.

  • Layers of the heart wall.

    The heart wall layers are epicardium (outer), myocardium (muscle), and endocardium (inner lining).

  • Function of atrioventricular (AV) and semilunar (SL) valves.

    AV valves prevent backflow into atria during ventricular contraction; SL valves prevent backflow into ventricles after blood is ejected.

  • What is angina pectoris?

    Angina pectoris is chest pain caused by reduced blood flow to heart muscle.

  • What is myocardial infarction (MI)?

    Myocardial infarction or heart attack is death of heart muscle due to prolonged lack of blood supply.

  • Define intercalated discs in cardiac muscle.

    Intercalated discs are specialized connections between cardiac muscle cells containing desmosomes and gap junctions for mechanical and electrical coupling.

  • What initiates the heart's intrinsic conduction system?

    The pacemaker cells in the sinoatrial (SA) node initiate the heart's rhythmic action potentials.