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Describe the major functions of the endocrine system
The endocrine system regulates body functions to maintain homeostasis and coordinates communication through hormones. It complements the nervous system but operates through ductless glands that secrete hormones into the bloodstream for targeted action.
Compare and contrast how steroid and peptide hormones are produced in the endocrine cell, released from the endocrine cell, and transported in the blood
Production:
Steroid: Synthesized from cholesterol.
Peptide: Synthesized as amino acid chains.
Release:
Steroid: Diffuse through the cell membrane.
Peptide: Released via exocytosis.
Transport:
Steroid: Bound to plasma proteins.
Peptide: Dissolved in plasma.
Describe the anatomy of the pancreas… and the hormones’ primary targets and effects
Located posterior to the stomach; both endocrine (islets of Langerhans) and exocrine functions.
Hormones:
Insulin: Lowers blood glucose by promoting cellular uptake and glycogen formation.
Glucagon: Raises blood glucose by glycogen breakdown.
Somatostatin: Inhibits insulin and glucagon secretion.
List the five types of leukocytes in order of their relative prevalence in normal blood, and describe their major functions.
Neutrophils (54-70%): First responders, strong phagocytes, combat bacterial infections.
Lymphocytes (25-33%): T-cells attack pathogens; B-cells produce antibodies.
Monocytes (3-9%): Develop into macrophages, engulf pathogens and debris.
Eosinophils (1-3%): Combat parasitic worms, moderate allergic reactions.
Basophils (<1%): Release histamine and heparin, promote inflammation
Describe the process of fibrinolysis, including the roles of plasminogen, tissue plasminogen activator, and plasmin
Process: Breakdown of fibrin in clots.
Key Players:
Plasminogen: Inactive precursor.
Tissue Plasminogen Activator (tPA): Converts plasminogen to plasmin.
Plasmin: Enzyme that dissolves fibrin
Define the terms hormone, endocrine gland, endocrine tissue (organ), and target cell.
Hormone: A chemical messenger secreted by endocrine glands that acts on specific target cells.
Endocrine Gland: Ductless organs that secrete hormones directly into body fluids.
Endocrine Tissue (Organ): Structures with cells that release hormones, e.g., pancreas and thyroid gland.
Target Cell: A cell with specific receptors for a hormone, enabling it to respond to hormonal signals.
Compare and contrast the mechanisms of action of plasma membrane hormone receptors and intracellular hormone receptors.
Plasma Membrane Receptors: Bind nonsteroid hormones, activating second messengers (e.g., cAMP) for signal transduction.
Intracellular Receptors: Bind steroid hormones that directly modulate gene transcription.
Describe a simple endocrine pathway in which the response is the negative feedback signal (e.g., parathyroid hormone, insulin).
Parathyroid Hormone (PTH):
Secreted in response to low blood calcium.
Increases calcium release from bones, calcium absorption in intestines (via vitamin D), and calcium reabsorption in kidneys.
Describe the structure and function of hemoglobin, including its breakdown products.
Structure: Composed of 4 globin chains, each with a heme group containing iron.
Function: Binds oxygen (oxyhemoglobin) and releases it in tissues.
Breakdown: Globin → amino acids; heme → iron (recycled) and biliverdin → bilirubin (excreted in bile)
Trace the path of blood through the right and left sides of the heart… and indicate whether the blood is oxygen-rich or oxygen-poor
Right Side: Vena cava → right atrium → tricuspid valve → right ventricle → pulmonary valve → pulmonary arteries → lungs (oxygen-poor).
Left Side: Pulmonary veins → left atrium → mitral valve → left ventricle → aortic valve → aorta → body (oxygen-rich)
Compare and contrast how the nervous and endocrine systems control body functions
Similarities: Both use chemical signals (neurotransmitters for the nervous system; hormones for the endocrine system) and bind to receptors on target cells.
Differences:
Nervous system: Fast, short-lived responses via synapses.
Endocrine system: Slower, longer-lasting responses via blood circulation.
Describe the locations and anatomical relationships of the hypothalamus, anterior pituitary, and posterior pituitary, including the hypothalamic-hypophyseal portal system
The hypothalamus is at the base of the brain, connected to the pituitary gland via the pituitary stalk (infundibulum).
Anterior Pituitary: Glandular tissue, controlled by hypothalamic releasing/inhibiting hormones via the hypophyseal portal system.
Posterior Pituitary: Neural tissue, stores and releases hormones (e.g., ADH, oxytocin) produced by the hypothalamus.
Describe examples of how the endocrine organs interact with other body organs and systems to maintain homeostasis.
Thyroid: Regulates metabolism, influenced by the hypothalamus and pituitary.
Adrenal Glands: Release cortisol for stress and sodium balance.
Pancreas: Maintains blood glucose levels.
These organs interact with other systems (e.g., skeletal, nervous, cardiovascular) to ensure balanced body functions.
Explain the basic process of erythropoiesis, the significance of the reticulocyte, and regulation through erythropoietin (EPO)
Process: Hematopoietic stem cell → erythroblast → reticulocyte → erythrocyte.
Significance of Reticulocyte: Immature RBC, indicative of active RBC production.
Regulation by EPO: Low oxygen triggers kidney and liver to release EPO, stimulating RBC production
List the parts of the electrical conduction system of the heart in the correct sequence…
SA node → 2. Atrial syncytium → 3. AV node → 4. AV bundle → 5. Bundle branches → 6. Purkinje fibers
Describe the various signals that initiate hormone production and secretion (e.g., monitored variables, direct innervation, neurohormones, other hormones)
Monitored Variables: Changes in blood composition (e.g., calcium, glucose levels).
Direct Innervation: Nervous system stimulation (e.g., adrenal medulla by sympathetic nerves).
Neurohormones: Hypothalamic releasing/inhibiting hormones control the anterior pituitary.
Other Hormones: Tropic hormones stimulate hormone secretion in target glands.
Explain the role of hypothalamic neurohormones (regulatory hormones) in the release of anterior pituitary hormones.
Hypothalamic neurohormones (e.g., TRH, CRH) regulate the release of anterior pituitary hormones, which in turn control peripheral endocrine glands.
Describe the major functions of each component of the cardiovascular system (i.e., blood, heart, blood vessels)
Blood: Transports oxygen, nutrients, hormones, and waste; regulates pH, temperature, and fluid balance; provides immunity.
Heart: Pumps blood through the pulmonary and systemic circuits, ensuring oxygen-poor blood reaches the lungs and oxygen-rich blood supplies the body.
Blood Vessels: Arteries transport blood away from the heart; veins return blood to the heart; capillaries facilitate nutrient, gas, and waste exchange
Describe the role of platelets in hemostasis and the steps involved in the formation of the platelet plug
Role: Platelets adhere to vessel injury sites, forming a temporary plug.
Steps:
Platelet adhesion (to collagen and von Willebrand factor).
Platelet activation (shape change, release of factors like serotonin and thromboxane).
Platelet aggregation (plug formation)
Name the waveforms in a normal electrocardiogram (ECG) and explain the electrical events represented
P wave: Atrial depolarization.
QRS complex: Ventricular depolarization.
T wave: Ventricular repolarization
Compare and contrast negative feedback for hypothalamic-anterior pituitary-peripheral endocrine gland pathways to negative feedback for most simple endocrine pathways
Hypothalamic-Anterior Pituitary-Peripheral Endocrine Gland Pathways: Involves multiple layers of negative feedback (e.g., hypothalamic and pituitary hormones are inhibited by the final hormone in the pathway).
Simple Endocrine Pathways: Feedback occurs directly through the monitored variable (e.g., parathyroid hormone secretion is regulated by blood calcium levels).
Describe major hormones secreted by the anterior pituitary, their control pathways, and their primary target(s) and effects
FSH, LH, ACTH, TSH, PRL, GH.
Controlled by hypothalamic releasing/inhibiting hormones.
Targets: Gonads, adrenal cortex, thyroid, mammary glands, and growth-related tissues.
Compare and contrast the morphological features and general functions of the formed elements (i.e., erythrocytes, leukocytes, platelets)
Erythrocytes (RBCs): Biconcave, lack nucleus, transport oxygen and carbon dioxide via hemoglobin.
Leukocytes (WBCs): Have nuclei, defend against infections and remove debris.
Platelets: Small cell fragments, essential for clotting and wound repair
Explain the role of vitamin K in blood clotting
Required for the synthesis of certain clotting factors (e.g., prothrombin), critical for blood coagulation
Describe the phases of the cardiac cycle…
Atrial systole: Atria contract.
Ventricular systole: Ventricles contract.
Diastole: Chambers relax