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Endocrine System. Jordan S. Kelsey G. Jena P. Sam P. Endocrine System. A network of glands that secrete hormones, which travel in the bloodstream and affect the functioning of target cells. Function. Work alongside the nervous system
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Endocrine System Jordan S. Kelsey G. Jena P. Sam P.
Endocrine System • A network of glands that secrete hormones, which travel in the bloodstream and affect the functioning of target cells
Function • Work alongside the nervous system • Maintaining homeostasis throughout the body through feedback mechanisms
Endocrine vs. Exocrine Endocrine Exocrine Secrete fluids out of the body Ex: Sweat and oils • Secrete hormones into the internal environment • Diffuse into the interstitial fluid into the bloodstream and act on target cells
Hormones • Most are steroids synthesized from cholesterol • Or they are amines, peptides, proteins or glycoproteins produced from amino acids, or non-steroid hormones • Stimulate changes in target cells
Steroid Hormones • Cannot dissolve in water but can in lipid • Thus allowing them to enter through the target cell membrane • Steroid bonds to a receptor and triggers transcription of specific regions of DNA resulting in mRNA • Weakly bound to plasma • Released in large quantities near their target cells
Steroid Video • https://www.youtube.com/watch?v=CaMKuXKZ70g
Non-Steroid Hormones • Usually bind receptors in target cell membranes • Activates adenylatecylase • Then catalyzes conversion of ATP to cAMP • cAMP promotes a series of reactions leading to cellular changes linked with the hormones action • These hormones do not penetrate the cell membrane into the nucleus as steroid hormones do
Secretion • Nervous system works to control secretion within the endocrine system • Nerve impulse is transmitted through the neuron • Reaches the glandular cells to secrete a hormone into the bloodstream or to stop the hormone • Hormone responds to target cells • Has no effect on other cells
Location • Endocrine glands are located in: • Brain • Throat • Upper abdominal region • Pelvic Region • Secrete hormones internally
Pituitary Gland Located at the base of the brain where the pituitary stalks connect it to the hypothalamus Anterior Posterior Antidiuretic hormone Oxytocin • Growth hormone • Prolactin • Thyroid Stimulating hormone • Adrenocorticotropic hormone • Follicle stimulating hormone • Luteinizing hormone
Hypothalamus • Attached to the pituitary gland by the pituitary stalk • In charge of releasing the nerve impulses to the posterior pituitary which then signals the hormone release • Controls the secretion of the anterior pituitary • Thyrotropic releasing hormone • Corticotropin releasing hormone
Thyroid Gland • Located just below the larynx on either side and in front of the trachea • Thyroxine • Triodothyronine • Calcitonin
Adrenal Glands Adrenal Medulla Adrenal Cortex Aldosterone Cortisol Sex hormones • Consists of 2 parts: adrenal medulla and the adrenal cortex • The adrenal glad is located right above the kidneys • Epinephrine • Norepinephrine
Reproductive Glands Ovaries Testes Testosterone • 2 Main reproductive organs that secrete important hormones are the ovaries and testes • Located in the pelvic region of the body • Estrogen • Progesterone
Pancreas • Digestive juice secreting exocrine gland • A hormone secreting endocrine gland located posterior to the stomach and behind the parietal peritoneum • Glucagon • Insulin
Pineal Gland • Located deep between the cerebral hemispheres • Attaches to the upper portion of the thalamus • Melatonin
Parathyroid • Usually 4 parathyroid glands • Located on the posterior surface of the thyroid gland • Parathyroid hormone(PTH)
Thymus • Lies in the mediastinum posterior to the sternum and between the lungs • Large in young kids but shrinks after puberty and with age • Thymosins
Negative Feedback Systems • A way of controlling hormone secretion • An endocrine gland or system controlling it senses the concentration of the hormone the gland secretes, a process the hormone controls, or an action the hormone has on the internal environment
Diseases • Diabetes: person has high blood glucose • Insulin production in inadequate or the body’s cells do not respond properly to insulin, or both • Adrenocortical Carcinoma: rare disease in which malignant(cancer) cells form in the outer layer of the adrenal gland
Diseases Continued • Growth Disorders • body produces too much growth hormone, gigantism or acromegaly can occur • Too little growth hormone results a condition called growth hormone deficiency • Can cause children to grow more slowly than normal