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HORMONES & THE ENDOCRINE SYSTEMS., HORMONES & HOMEOSTASIS,…

- - - - produce milk, while nursing there is a high level of PRL which prevent releasing of eggs decreasing the chance to get pregnant.
      - birds; regulates fat metabolism & reproduction.
        
        amphibians ; it stimulates the movement in water for preparation in breeding
- - - - = pancreas does not produce enough insulin.
      - can develop during childhood.
      - INSULIN DEPENDENT
    - - associated with being overweight & inactive.
      - NON-INSULIN DEPENDENT
    - - GESTATIONAL DIABETES.
    - - usually occurs after a meal, or by hunger, weakness, nervousness.
      - when person receive inadequate amounts of glucose they may develop convulsions, unconscious and die...
- - - - promotes maternal bonds
        
        promote a strong emotional bond
- - - - controlled by nerve signals
        
        secretes fish/flight hormone : sudden action ready for surprise of stress stimulated by physical threat .
        
        epinephrine : adrenaline, & norepinephrine : noradrenaline :secreted by adrenal medulla response to stress from physical threat that prepares body organs for action.
        
        stimuli +/- active certain nerve cells in the hypothalamus => cell send nerve signals via spinal cord to adrenal medulla, stimulating secretion of epinephrine & norepinephrine into blood.
        
        prepare body for action by raising heart & breathing & metabolic rate & blood pressure.
        
        epinephrine & norepinephrine change blood flow patterns making some organs less/more active.
    - - controlled by ACTH from the anterior pitituitary.
        
        secretes hormones " glucocorticoids & mineralocorticoids "
        
        Glucocorticoid : corticosteroid hormone secreted by the adrenal cortex that increases the blood glucose level & helps maintain the body's response to stress from low blood sugar/ decreased blood volume & pressure.
        
        Mineralocoticoid : corticosteroid hormone secreted by the adrenal cortex that helps maintain salt& h2o homeostasis & may increase blood pressure in response to stress from low blood sugar/ decreased blood volume/pressure.
      - respond to hormone signals.
        
        low blood sugar, blood volume & pressure.
      - hypothalamus secretes releasing hormone which stimulates target cells in the anterior pituitary to secrete ACTH
        
        ACTH (Adrenocorticotropic hormones) :protein hormone secreted by anterior pituitary that stimulates the adrenal cortex to secrete corticosteroids.
        
        corticosteroid : hormone synthesised & secreted by the adrenal cortex. includes minerlocoticoid & glucocoticoids.
- - - - Thyroid hormone : T3 + T4 ;hormones that performs several functions &stimulates metabolism.
        
        plays a lot of role as a hormone in mammals.
        
        when homeostasis is not maintained in thyroid hormones = serious metabolic disorder
        
        excess of thyroid hormone in blood(hyperthyroidism) = overheat, sweat, high blood pressure, lose weight.
        
        commonly caused by autoimmune reaction
        
        result for dietary disorders
        
        Goiter : enlargement fo thyroid gland resulting from a dietary iodine defiency.
        
        thyroid cannot synthesise adequate amounts of hormone without enough iodine.
        
        insufficient hormone = weight gain, lethargy, intorelance to cold
- - - - anterior pituitary secretes FSH and LH
    - - Testosterone : androgen hormone ; stimulates the embryo to develop into a male & promotes the male body features
      - puberty time , high concentrations of androgen triggers the development of male characteristics.
- - - - regulate the level of glucose in the blood & control the circulation of glucose in the body.
      - insulin & glucagon is antagonist hormones : two hormones that have opposite effects.
      - balance of insulin & glucagon maintains the homeostatic set point of glucose.
      - 2 negative feedback systems manage the amount of glucose in the blood.
        
        one lowers the release of insulin and another raises the release of glucagon.
        
        excess of glucose is stored in liver and muscle cells called glycogen in polysaccharide form.
        
        when blood contains glucagon, glycogen is broken down releasing glucose back to blood.
    - - each islets = beta cells which produces insulin & alpha cells which produces glucagon.
- - - - hormones produced by endocrine glands have a wide range of effects
      - adrenal glands are stimulated by the nervous system directly.
    - - melatonin : hormones that link environmental light conditions with biological rhythms
      - release of melatonin is controlled by groups of neurons in the brain.
      - melatonin that is secreted at night , plays role in promoting sleep.
      - synthesises and secretes melatonin.
- - - - responds by sending out appropriate nervous or endocrine signals
    - - consist of 2 parts : 1. Posterior lobe : which stores and releases 2 hormones produced by the hypothalamus. 2.Anterior lobe : produces and secretes many hormones that regulate diverse body functions.
        
        Posterior pituitary : Extension of the hypothalamus composed of nervous tissue that secrets hormones made in the hypothalamus. - Temporary storage site for the hypothalamic hormones.
        
        sets of neurosecretory cells help connect the hypothalamus and posterior pituitary structurally and functionally.
        
        Anterior pituitary :Endocrine gland that both synthesises and secretes hormones.
        
        neurosecretory cells secretes 2 types of cell into the anterior pituitary : releasing hormone& inhibiting hormone.
        
        Releasing hormone : kind of hormone secreted by the hypothalamus that promotes the release of hormones form the anterior pituitary.
        
        stimulate the anterior pituitary to secrete one/more hormones.
        
        Inhibiting hormone: kind of hormone released form the hypothalamus that prompts the anterior pituitary to stop secreting one/ more hormones.
        
        TSH(Thyroid-stimulating hormone) -regulates hormone production by the thyroid gland.
        
        ACTH(adrencorticotropic hormone) stimulates the cortex, releasing the hormone that affect the h2o balance & metabolism.
        
        (PRL)Prolactin : a protein hormone secreted by the anterior pituitary that stimulates the human mammary glands to produce milk& produces other responses in different animals.
        
        (GH) Growth Hormone : protein hormone secreted by the anterior pituitary that promotes development and growth& stimulates metabolism.
        
        1 more item...
- - - - Endocrine system : a group of interacting glands and tissues that produce and secrete chemicals to initiate and maintain body functions.
        
        Hormones : a regulatory chemical that travels in the blood from its production site. released by endocrine chemicals.
        
        it regulates long-term development process.
        
        in endocrine system; suited for coordinating gradual changes that affect the entire body.
        
        in nervous system; signals are transmitted through neutrons. Well-Adapted for directing immediate and rapid response to the environment.
    - - hormones travel via circulatory system to all body parts, but only target cells have specific receptor for that hormone.
        
        depending on the site of the target cell, the hormone can affect that single spot / whole body.
        
        cell signals travel alongs neuron to a specific cell.
        
        only in nervous system there is a direct connection between the neuron transmitting the signal and target cell is responding.
        
        TARGET CELL : a cell that respond to a regulatory signal.
        
        hormones last for about an hour while signal cells last for >secs
    - - both endocrine & nervous systems respond to the stimuli to coordinate body functions.
  - - - to determine whether a chemical pollutant causes a specific biological effect , scientist do control studies on frogs.
  - - - reception
        
        occurs when a hormone binds to a specific receptor protein/ target cell.
        
        each target cell receptor has a unique shape that function to recognise a specific signal
      - 2.signal transduction
        
        convert the signal from one form to another. => response
      - 3.response
        
        change in animal behaviour
    - - Water-Soluble Hormones
        
        cannot pass through the phospholipid bilayer of the plasma membrane.
        
        The receptor proteins for most water- soluble hormones are embedded in the plasma membrane of target cells
        
        water-soluble hormones bind to plasma membrane receptors
        
        water-soluble hormones may affect gene expression or have other effects
      - Lipid-Soluble Hormones
        
        lipid-soluble hor- mones pass through the phospholipid bilayer and bind to receptors inside the cell
        
        Lipid-soluble hormones bind to receptors inside the cell
        
        Lipid-soluble hormones affect gene expression