Yr 12 Human Biology syllabus answered.docx - The endocrine system The hypothalamus pituitary gland thyroid parathyroid pancreas thymus gonads pineal and

Yr 12 Human Biology syllabus answered.docx - The endocrine...

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The endocrine system The hypothalamus, pituitary gland, thyroid, parathyroid, pancreas, thymus, gonads, pineal and adrenal glands, that are endocrine glands found in the human body. -The endocrine system regulates the activity of cells by sending out hormones, they are chemical messengers. - The endocrine system maintains a constant environment inside of the body called homeostasis. -When the body experiences a change it is a stimulus. Endocrine glands (Ductless glands) -Endocrine glands release hormones to the extra-cellular fluid that surround the cells of the gland. -The secretions pass through the capillaries -They get to the bloodstream to be transported to the target organs. Exocrine glands -Exocrine glands secrete substances out to the epithelial surface (external surface) via a duct. -Examples are sweat glands, oil glands, salivary glands, mucous glands etc. Explain how hormones secreted from the hypothalamus, pituitary, thyroid, parathyroid, thymus, gonads, pineal, pancreas and adrenal glands are involved in homeostasis by affecting specific target organs . Hypothalamus -It is located in the base of the brain -regulates body temperature, water balance and heart rate, sleep patterns, eating patterns. -A lot of functions of the hypothalamus happen in the pituitary gland A.K.A ‘Master gland’ -The hypothalamus produces releasing and inhibiting factors for the anterior lobe and it produces hormones ADH and oxytocin for the posterior lobe. -The posterior lobe is connected by nerve fibers that run through infundibulum. -The anterior lobe is connected by complex blood vessels in the infundibulum.
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The production of hormones in the hypothalamus There are two sets of nerve cells in the hypothalamus that produce hormones. One set sends the hormones they produce down through the pituitary stalk to the posterior lobe. The other set produces releasing and inhibiting factors that get sent down the complex blood vessels in the infundibulum to the anterior lobe where they are then stored and released when needed. Anterior lobe The anterior lobe secretes hormones that control many of the body’s activities. Hormones start to release from the anterior lobe once ‘releasing factors’ have been secreted from the hypothalamus. The hypothalamus also releases ‘inhibiting factors’ to slow secretion down. Hormones releases by the anterior lobe include: - Gonadotropins (FSH, LH) ; Hormones that affect the sexual organs such as the testes and ovaries. - Follicle-stimulating hormone (FSH) in the ovary to stimulate the growth of eggs - Growth hormone (GH) which stimulates body growth and maintains size of organs. - Prolactin (PRL) which works with other hormones to help secret milk in females. - Thyrotropin or (TSH) which stimulates production or release of thyroid hormones -Adrenocorticotrophic (ACTH) hormone controls the production and release of hormones from the adrenal cortex Posterior lobe The Oxytocin and ADH hormones are produced by a special set nerve cells in the hypothalamus
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  • Fall '18
  • maya

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