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Anatomy & Physiology: Endocrine System and Blood Study Guide

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Terms in this set (46)

  • What are hormones and which glands produce them?

    Hormones are chemical messengers produced by endocrine glands that regulate body functions.

  • What is a target tissue and a receptor?

    A target tissue is a tissue affected by a hormone; a receptor is a protein on or in target cells that binds the hormone.

  • Which organs produce both endocrine and exocrine products? Which is part of the nervous system?

    The pancreas produces both endocrine (hormones) and exocrine (digestive enzymes) products. The hypothalamus is part of the nervous system and produces hormones.

  • Define homeostasis.

    Homeostasis is the maintenance of a stable internal environment despite external changes.

  • What is negative feedback in hormone regulation?

    Negative feedback is a control mechanism where a hormone's effect reduces its own production to maintain balance.

  • Define biorhythm and give examples of hormones with daily, monthly, and seasonal rhythms.

    Biorhythm is a cyclic pattern of hormone release; examples include daily cortisol, monthly estrogen, and seasonal melatonin rhythms.

  • Major types of hormones based on chemical class?

    Hormones are classified as amino acid derivatives, peptides/glycoproteins, and steroids, differing in structure and solubility.

  • Difference between hydrophobic and hydrophilic hormones?

    Hydrophobic hormones (steroids) are lipid-soluble, bind intracellular receptors, and use direct gene activation. Hydrophilic hormones (peptides) are water-soluble, bind surface receptors, and use second messengers.

  • Direct gene activation vs. second messenger mechanisms?

    Direct gene activation is used by hydrophobic hormones binding intracellular receptors to alter gene expression. Second messengers are used by hydrophilic hormones binding surface receptors to activate signaling cascades.

  • What is upregulation and downregulation?

    Upregulation increases receptor numbers to enhance sensitivity; downregulation decreases receptors to reduce sensitivity.

  • Difference between free and bound hormones?

    Free hormones circulate unbound and are usually hydrophilic. Bound hormones are attached to transport proteins, typically hydrophobic steroids, increasing their half-life.

  • Define permissiveness, synergism, and antagonism in hormone interactions.

    Permissiveness: one hormone enables another's effect. Synergism: hormones amplify each other's effects. Antagonism: hormones oppose each other's effects.

  • Types of stimuli for hormone release?

    Humoral: changes in blood chemistry; Neural: nervous system signals; Hormonal: hormones stimulate other hormones.

  • Location and relationship of hypothalamus, anterior and posterior pituitary?

    The hypothalamus is above the pituitary; it controls the anterior pituitary (adenohypophysis) via releasing/inhibiting hormones and the posterior pituitary (neurohypophysis) stores hormones made by hypothalamic neurosecretory cells.

  • What are neurosecretory cells and their hormones?

    Neurosecretory cells in hypothalamus produce oxytocin and antidiuretic hormone (ADH), stored and released by the posterior pituitary.

  • Difference between neurohypophysis and adenohypophysis?

    Neurohypophysis stores/releases hypothalamic hormones (ADH, oxytocin). Adenohypophysis synthesizes and secretes its own hormones under hypothalamic control.

  • Define tropic hormone and examples from hypothalamus and anterior pituitary.

    Tropic hormones stimulate other endocrine glands. Examples: hypothalamic TRH, CRH, GnRH; anterior pituitary TSH, ACTH, FSH, LH.

  • Function of thyroid stimulating hormone (TSH)?

    TSH is produced by the anterior pituitary; stimulated by hypothalamic TRH; it stimulates the thyroid gland to produce thyroid hormones.

  • Role of adrenocorticotropic hormone (ACTH)?

    ACTH is produced by the anterior pituitary; stimulated by hypothalamic CRH; it stimulates the adrenal cortex to release glucocorticoids.

  • Functions of follicle stimulating hormone (FSH) and luteinizing hormone (LH)?

    Produced by anterior pituitary; stimulated by hypothalamic GnRH; FSH promotes gamete production; LH triggers sex hormone production and ovulation.

  • Growth hormone (GH) production and effects?

    Produced by anterior pituitary; stimulated by GHRH and inhibited by GHIH from hypothalamus; GH promotes growth directly and indirectly via somatomedins from liver.

  • Prolactin (PRL) function and regulation?

    Produced by anterior pituitary; stimulated by PRH and inhibited by PIH; PRL targets mammary glands to promote milk production.

  • Where is the thyroid gland and what hormones does it produce?

    The thyroid gland is in the neck; it produces thyroid hormone (T3 and T4) regulating metabolism and calcitonin regulating blood calcium.

  • What are thyroid follicles and colloid?

    Follicles are spherical units producing thyroid hormone; colloid is stored hormone precursor inside follicles.

  • What are parafollicular cells and their hormone?

    Parafollicular cells are in thyroid gland; they produce calcitonin, which lowers blood calcium.

  • How do T3 and T4 affect metabolism and how are they regulated?

    T3 and T4 increase metabolic rate; synthesized from iodine and tyrosine; regulated by hypothalamic TRH and pituitary TSH via negative feedback.

  • What is the role of calcitonin?

    Calcitonin lowers blood calcium by inhibiting osteoclasts, stimulating osteoblasts, and increasing kidney calcium excretion; released when blood calcium is high.

  • Where are parathyroid glands and what hormone do they produce?

    Located on thyroid's posterior surface; produce parathyroid hormone (PTH) which raises blood calcium levels.

  • How does parathyroid hormone (PTH) regulate blood calcium?

    PTH increases blood calcium by stimulating osteoclasts, reducing kidney excretion, and enhancing intestinal absorption; released when calcium is low.

  • Pancreas endocrine and exocrine functions?

    Exocrine pancreas produces digestive enzymes; endocrine pancreas (islets) produces hormones like insulin and glucagon regulating blood glucose.

  • Effects of glucagon on blood glucose?

    Glucagon raises blood glucose by stimulating glycogenolysis and gluconeogenesis; released when blood glucose is low.

  • Effects of insulin on blood glucose?

    Insulin lowers blood glucose by promoting glycogenesis and glucose uptake into insulin-dependent cells; released when blood glucose is high.

  • Location and hormone production of adrenal glands?

    Located above kidneys; adrenal cortex produces steroid hormones (glucocorticoids, mineralocorticoids); adrenal medulla produces catecholamines (epinephrine, norepinephrine).

  • What is the fight or flight response?

    Triggered by adrenal medulla hormones; prepares body for stress by increasing heart rate, blood flow, and energy availability.

  • Functions of glucocorticoids and mineralocorticoids?

    Glucocorticoids (e.g., cortisol) regulate metabolism and suppress inflammation; mineralocorticoids (e.g., aldosterone) regulate sodium and water balance.

  • What stimulates aldosterone release?

    Aldosterone release is stimulated by ACTH and the renin-angiotensin system in response to low blood pressure or sodium.

  • Where are gonads and what hormones do they produce?

    Female gonads are ovaries producing estrogen and progesterone; male gonads are testes producing testosterone.

  • Where is the pineal gland and what hormone does it produce?

    The pineal gland is in the brain; it produces melatonin, which regulates circadian rhythms.

  • What is hematocrit?

    Hematocrit is the percentage of blood volume occupied by red blood cells.

  • What are the formed elements of blood?

    Formed elements include erythrocytes (RBCs), leukocytes (WBCs), and platelets.

  • What is the main function of erythrocytes?

    Erythrocytes transport oxygen bound to hemoglobin from lungs to tissues.

  • Define leukocytosis and leukopenia.

    Leukocytosis is an elevated white blood cell count; leukopenia is a decreased white blood cell count.

  • What is hemostasis?

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

  • What is the difference between a thrombus and an embolus?

    A thrombus is a stationary blood clot; an embolus is a clot or debris that travels through the bloodstream.

  • What determines ABO blood groups?

    ABO blood groups are determined by the presence or absence of specific surface antigens on red blood cells and corresponding antibodies in plasma.

  • What causes hemolytic disease of the newborn and how is it prevented?

    It occurs when an Rh-negative mother produces antibodies against Rh-positive fetal blood; prevented by administering Rh immunoglobulin to the mother.