Endocrine System - A&P 2 Lab PDF

ENDOCRINE SYSTEM Endocrine control of Homeostasis There are 2 main control systems of the body that maintain homeostasis: 1) endocrine and 2)nervous Endocrine system influences metabolic activity by secreting hormones into blood to travel to specific target cells Hormones: chemical m...

ENDOCRINE SYSTEM Endocrine control of Homeostasis There are 2 main control systems of the body that maintain homeostasis: 1) endocrine and 2)nervous Endocrine system influences metabolic activity by secreting hormones into blood to travel to specific target cells Hormones: chemical messengers Amino acid type hormones or steroid type hormones Is scattered through the body as cells, tissues or organs Endocrine operates more slowly with longer effects  General Endocrine Characteristics Endocrine glands: Made up of epithelial cells Generally cuboidal Ductless glands Never using a duct Releases hormones directly into extracellular fluid (ECF) or blood  General Endocrine Anatomy Endocrine tissue can be variety of forms: don't have to memorize Whole gland: parathyroid and thyroid Partial gland: anterior and posterior pituitary Partial organ: islets of pancreas Patches of tissue in an organ: gastrin releasing cells in wall of stomach Neuroendocrine: hypothalamus, adrenal medulla Malignant tissue: lung cancer Endocrine Anatomy Be able to identify for quiz or test know this slide, will be questions Thyroid Gland Butterfly Shape Location: in the anterior neck, on the trachea just inferior to larynx (voice box) Releases thyroid hormones aka T-hormones Can you feel your thyroid? Swallow and you can feel your thyroid move up and down you can see the anterior of the thyroid glands Thyroid Gland: Histology Follicles Hollow and spherical, may contain Colloid (protein) Follicular Cells Form the walls of each follicle Cuboidal or squamous epithelial cells think beside follicular cell Parafollicular cell (aka Extrafollicular) Cells between follicular cells Thyroid Gland: Hormones Follicles May release stored thyroid hormones by attaching to the colloids Follicular Cells Synthesizes T3 (active form) and T4 (thyroxin) T3 increases metabolic rate and cell oxidation (increases calorie usage in cell) Parafollicular Cells Release calcitonin which lowers blood Ca++ Colloid filled follicles Blood vessel Parafollicular cells  Thyroid and Parathyroid Thyroid Tissue -notice the follicles superficial Parathyroid to thyroid Tissue -this is what we are looking for in these slides Parathyroid Glands 4 bean shaped glands Number may vary from person to person Location: on posterior thyroid  Parathyroid: Histology know this slide Chief cells Stain blue-purple Look like little black dots Release PTH (parathyroid hormone) which increases blood level Ca++ Larger Oxyphils Lighter shaded cells Have unknown function  Parathyroid Chief cells Oxyphil Cells Pancreas Aids in chemical digestion Location: found partially behind stomach Composed of both endocrine and exocrine glands called acinar cells Islets of Langerhans and acinar cells Pancreas: Histology The Islets of Langerhans Islets are round and lighter stained Contains endocrine cells of pancreas (alpha/beta cells) Islets account for small amount of pancreatic cells ~2% Acinar cells Exocrine cells of the pancreas Darker cells that surround Islets of Langerhans Acinar Cells the lighter islets Pancreas: Islets of Langerhans Made up of: Alpha cells red Hormone Released: glucagon which increases blood glucose Appear bright pink and are at the periphery Beta cells blue Hormone Released: insulin which lowers blood glucose Appear grey-blue and larger than alpha cells Delta cells Hormone Released: somatostatin Pituitary Gland: Anterior & Posterior Also known as Hypophysis Location: seated in the sphenoid bone Has two major lobes: Anterior pituitary- composed of glandular tissue Posterior pituitary- composed of mainly neural tissue  Anterior Pituitary Also known as Adenohypophysis Activity is controlled by the hypothalamus by chemical stimulus Manufactures and releases six protein hormones Four of the hormones are tropic hormones Tropic Hormones: Those that target other endocrine glands systems to secrete other hormones. Made of cuboidal cells Be able to identify the two major stains (use low power) Anterior Pituitary: Histology Anterior Pituitary Hormones Hormones from acidophilic cells Stain orange/brown Growth hormone (GH)- targets the liver, muscle, bone, and cartilage and stimulates somatic growth/mobilizes fat Anabolic hormone: tissue building hormone Prolactin (PRL)- targets breast secretory tissue and promotes lactation milk Anterior Pituitary: Hormones Hormones from basophilic cells Stains blue-purple Release tropic hormones: Thyroid stimulating h. (TSH)- targets the thyroid gland and stimulates thyroid gland to release t-hormones Adrenocorticotropic h. (ACTH)- targets the adrenal cortex to release its hormones Follicle stimulating h. (FSH)- targets the ovaries and testes; stimulates ovarian follicle maturation and estrogen production, and stimulates sperm production Luteinizing h. (LH)- targets the ovaries and testes; stimulates ovulation, and production of testosterone  ANTERIOR PITUITARY Basophils Acidophils Posterior Pituitary Neuroendocrine [Neurohypophysis] Stores and releases hormones made by the hypothalamus Remember: it does not synthesize the hormones, only stores them “hormone storage area” Hormones released: Oxytocin- targets the uterus to stimulate contractions; induces labor Antidiuretic Hormone (ADH)- targets the kidneys and stimulates the tubule cells to reabsorb water and return to blood Locate glial cells (Pituicytes) and nerve axons in slides/micrographs of posterior pituitary Hypophysis (pituitary) Posterior Anterior Glandular Tissue Anterior pituitary Posterior pituitary Neural Tissue  Adrenal Glands: Histology Pyramid shaped Location: on top or close to kidneys, one on top of each kidney How many adrenal glands should you have? Adrenal Glands Medulla: internal gland Adrenal gland Lightly stained whole Produces epi (80%) and norepi (20%) in the stress Capsule syndrome Adrenal cortex with 3 zones Medullary Cortex area area Each zone can be viewed under a scope Each produces a different hormone Outer capsule: protective covering 3 Layers of Adrenal Cortex Zona Glomerulosa: outermost cortex layer Releases mineralocorticoid hormone: aldosterone Secretes K+ and retains body Na+ and water Zona Fasciculata: middle layer Releases glucocorticoid hormone: cortisol Stress hormone elevating blood glucose levels This layer is the thickest and cells are parallel Zona Reticularis: innermost cortex layer Releases gonadocorticoid hormone: androgens Sex hormones; androgens- development of secondary sex characteristics Picks up heavy stain and shows branched cells  3. Zona Distinguished layers reticularis Adrenal 2. Zona fasciculata 1. Zona Gland capsule glomerulosa Layers of the Adrenal gland Cort ex Medulla cells Goals for quizzing and testing Identify endocrine tissue slides by histological characteristics. Specifically pancreatic islets, adrenal cortex layers and medulla, thyroid follicles, parathyroid tissue, and pituitary tissue Identify the location of that endocrine tissue in the body. Identify the hormone released by that tissue and its effects. If different parts of a gland release different hormones, identify them Name the hormone from each cortical zone Define a tropic hormone. Name one.