Receptors are proteins and can be found on the cell membrane or in the cytoplasm.
Example- Pituitary is an endocrine gland that makes thyroid stimulating hormone (TSH) which stimulates thyroid to produce thyroxine.
Steroid hormones are derivatives of cholesterol. The two hormones on this slide look similar except for a few minor differences but these differences have a large impact on the function of the hormone. Insulin is an example of a protein based hormone Amines smaller molecules that are derived from the amino acid tyrosine.
Is what stimulates the release of an ovum from an ovary during ovulation.
Pea sized. Both lobes produce a lot of hormones.
Hypthalamus lies above the pituitary.
Hormones of neurosecretory neurons are released into the nearby capillaries and control the production and release of hormones by the near by anterior pituitary.
Realeasing hormones stimulate release of anterior pituitary hormones and inhibiting hormones inhibit the release of anterior pituitary hormones. Hormones produced in cell bodies of the neurosecretory neurons. They travel down the axons of the neurosecretory cells, which terminate in the lower part of the hypothalamus, just above the pituitary.
Capillaries containing RH and IH drain into a series of veins in the stalk of the pituitary. These veins drain into a capillary network located in the anterior pituitary. They then bind to their target cells causing them to release hormones. It is an unusual arrangement of blood vessels in which a capillary bed drains into a vein which then drains into capillaries.
Hormones have very different functions.
People differ in height and body build. These differences are attributable to nutrition and growth hormone. Stimulates growth in the body by promoting cellular enlargement and the number of cells through cell division. In bone GH stimulates cell division and protein synthesis in bone cells resulting in an increase in the length and width of bones. In muscle it stimulates the uptake of amino acids and protein synthesis. The more GH produced during the growth phase of the indivdual’s life cycle, the taller and heftier they will be. In men growth also stimulated by testosterone which is produced in the testes.
This is why sleep is so important to a child that is growing. GH secretion declines as we age.
Draw this on the board- when levels of GH are low GH-RH is released from hypothalamus which causes the anterior pituitary to produce and release GH. When levels of GH rise, production of GH-RH stops. Stress and exercise both stimulate the hypothalamus to release GH-RH directly through nervous system.
Dwarfism = stunted growth.
Picture of womain at 16 (no sign of disorder), 33, and 52. Facial features become course and hands and feet continue to grow throughout adulthood. Growth of vertebrae results in a hunched back. The tongue, kidneys, and liver often become quite enlarged.
Stimulated by TSH-RH from the hypothalamus. Regulation by thyroxine levels is by negative feedback. Receptors in the hypothalamus monitor circulating levels of thyroxine. When circulating levels are low the receptors signal to the hypothalamus to release TSH-RH. When thyroxine levels rise TSH-RH declines. TSH-RH is also stimulated by cold and stress.
T4 and T3 have several affects on the body. Because breaking down glucose produces energy and heat, increased levels of these hormones raise body temperature. Secretion of T3 and T4 is higher during cold winter months than during hot summer months.
Target organ is the outer region of the adrenal gland. Glucocorticoids are steroids. The production and release of ACTH is controlled by the hypothalamus which releases ACTH-RH and it travels to the pituitary.
Secretion directly controlled by ACTH-RH produced by hypothalamus. Levels of ACTH-RH regulated by many factors 2 of which are. Glucocorticoids increase blood glucose levels which ensures we have the additional energy we need to operate body systems, especially muscles when we are under stress.
Suckling stimulates sensory fibers in the breast which send nerve impulses to the hypothalamus. In the hypothalamus these impulses stimulate prolactin releasing hormone (PRH). PRH travels to the anterior pituitary where it stimulates prolactin secretion. Prolactin persists for many months, as long as suckling continues. Reduced suckling slows down prolactin secretion, causing milk production to decline.s
Neuroendocrine- a gland made of neural tissues that produce hormones. Derived from brain tissue during embryogenesis- it remains connected to brain throughout life. Posterior pituitary consists of the axons and terminal ends of neurosecretory cells in which these hormones are stored until they are released into the surrounding capillaries.
Oxytocin release is stimulated by suckling. At the end of pregnancy, in the hours prior to delivery the walls of the uterus and cervix stretch which activates stretch receptors. Impulses from stretch receptors in the uterus travel to the cells of the hypothalamus to release oxytocin into the blood. The hormone then travels in the blood to the uterus.
T4 and T3 are involved in controlling metabolism and heat production. Calcitonin helps to regulate blood levels of calcium.
Each follicle consists of a central region containing a gel-like glycoprotein cal thyroglobulin and a surrounding layer of cuboidal follicle cells that produces the thyroglobulin T3 and T4 are small molecules that are cleaved off of the thyroglobulin.
Iodized = iodine fortified.
Goiters were once common in Europe and US in areas where iodine has been leached out of the soil by rain. Crops grown in such soil failed to provide sufficient quantities of iodine. To counteract this, iodine, was added to table salt.
Though in this situation, the lack of thyroglobulin isn’t the problem- it’s the lack of iodine- so very little of the newly produced thyroglobulin will give rise to T3 and T4.
1. Biology 127- Human Biology Lecture 14Overview of Endocrine SystemPituitary & HypothalamusThyroid GlandPancreasAdrenal Glands
2. Overview of Endocrine SystemEndocrine System-made of small glands.Glands produce chemical- hormone
3. Overview of Endocrine SystemHormones- chemicals that are released into the bloodstream and travel to distant sites Endocrine cell Blood vessel Long-distance signalingTarget Cells- Cells that are Hormone travels affected by in bloodstream to target cells hormone. Target cell (c) Hormonal signaling
4. Overview of Endocrine SystemHormones- function in five areas:1) Homeostasis2) Growth and development3) Reproduction4) Energy production, storage and use5) BehaviorCells of body exposed to hormones 24 hours.
5. Overview of Endocrine SystemTarget Cells- are selective. Only respond to specific hormones.Only target cells have the receptor to hormone. EXTRACELLULAR FLUID Plasma membrane 1 Reception Receptor Signaling molecule
6. Overview of Endocrine SystemTwo types of hormones- Trophic and Nontrophic hormones.Trophic Hormones- stimulate other endocrine glands to produce and secrete other hormones
7. Overview of Endocrine SystemNontrophic hormones- stimulate cellular growth, metabolism, and other functions.Example- thyroxine
8. Overview of Endocrine SystemHormones can be classified based upon the type of molecule they are:1) Steroids; 2) Proteins; 3) Amines
9. Overview of Endocrine SystemHormones production is controlled by negative feedback loops- the end product of a process inhibits its production
10. Overview of Endocrine SystemHormones production is controlled by positive feedback loops- the end product of a process stimulates its production
11. Biology 127- Human Biology Lecture 14Overview of Endocrine SystemPituitary & HypothalamusThyroid GlandPancreasAdrenal Glands
12. Pituitary & HypothalamusPituitary Gland- found at base of skull. Has anterior and posterior sections
13. Pituitary & HypothalamusPituitary Gland- both anterior and posterior produce different hormones
14. Pituitary & HypothalamusPituitary Gland- both anterior and posterior produce different hormones
15. Pituitary & HypothalamusAnterior Pituitary controlled by hypothalamus- has receptors that monitor blood levels of hormones, nutrients, ions.
16. Pituitary & HypothalamusHypothalamus- its receptors stimulates neurosecretory neurons- synthesize and secrete hormones
17. Pituitary & HypothalamusHypothalamus- neurosecretory neurons produce releasing hormone (RH) and inhibiting hormone (IH). Stored in axons until needed.
18. Pituitary & HypothalamusHypothalamus- when needed RH and IH diffuse into capillaries- drain into pituitary by vein.
19. Pituitary & HypothalamusHypothalamus- vein drains into capillaries in anterior pituitary- portal system- capillaries drain to vein which drains to capillaries.
20. Anterior PituitaryAnterior Pituitary- secretes seven different hormones
21. Anterior Pituitary-Growth HormoneGrowth Hormone (GH)- a protein hormone that stimulates cell growth- targets muscles and bones.
22. Anterior Pituitary-Growth HormoneGrowth Hormone (GH)- undergoes a diurnal (daily) cycle. Highest levels present during sleep or exercise.
23. Anterior Pituitary-Growth HormoneGrowth Hormone (GH)- release controlled by hypothalamus in a negative feedback loop.
24. Anterior Pituitary-Growth HormoneGrowth Hormone (GH)- undersecretion during growth phase- dwarfism.Over secretion during growth phase- giantism.
25. Anterior Pituitary-Growth HormoneGrowth Hormone (GH)- excess GH production by pituitary after growth phase done causes acromegaly
26. Anterior Pituitary-TSHThyroid Stimulating Hormone (TSH)- stimulates thyroid gland to release its hormones.Regulated by daily levels of thyroxine- hormone produced by thyroid.
27. Anterior Pituitary-TSHThyroid Stimulating Hormone (TSH)- travels to thyroid- in neck.Stimulates production and release of:1) Thyroxin (T4)2) Triiodothyronine (T3)Stimulate breakdown of glucose by body cells.
28. Anterior Pituitary-ACTHAdrenocorticotropic Hormone (ACTH)- Stimulates release of hormones from adrenal cortex.Stimulates production of glucocorticoids- increase blood glucose levels.
29. Anterior Pituitary-ACTHAdrenocorticotropic Hormone (ACTH)- Secretion regulated by:1) Levels of glucocorticoids in blood (part of negative feedback loop).2) Stress- acting through nervous system.
30. Anterior Pituitary-ProtlactinProlactin- Acts on the mammary gland to stimulate milk production in the breasts.Controlled by a neuroendocrine reflex- involves both nervous and endocrine stimulation
31. Posterior PituitaryPosterior Pituitary Produces ADH and oxytocinIs a neuroendocrine glandHormones made in hypothalamus.Axons from these neurosecretory cells store hormones in pituitary
32. Posterior Pituitary- OxytocinOxytocin-1) Stimulates release of milk from mammary glands2) Causes uterine contractions during childbirth
33. Biology 127- Human Biology Lecture 14Overview of Endocrine SystemPituitary & HypothalamusThyroid GlandPancreasAdrenal Glands
34. Thyroid GlandThyroid Gland- located in the neck. Produces:1)Thyroxine (T4)2) Triiodothronine (T3)3) Calcitonin
35. Thyroid Gland- T3 & T4Thyroid Gland- consists of large spherical structures- follicles which contain gel-like substance- thyroglobulin.
36. Thyroid Gland- T3 & T4T3 and T4 contain iodine- we take it in through vegetables and iodized salt . (T4)
37. Thyroid Gland- T3 & T4Increase in thyroglobulin that isn’t used in T3 & T 4 production leads to enlargement of thyroid = goiter.
38. Thyroid GlandLack of dietary iodine causes low levels of T3 & T4.Hypothalmus signals to anterior pituitary to produce more TSH.TSH causes thyroid to increase thyroglobulin production.