Chapter 7 Endocrine system Flashcards Preview

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Flashcards in Chapter 7 Endocrine system Deck (23):

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What is the endocrine system? 

Made up of endocrine cells, tissues, organs and the hormones they produce


What are hormones and target cells?

  1. Hormone
    -Chemical messenger or signal molecule that helps maintain homeostasis
    -Act to regulate target cell’s activity
    -Hormones secreted into interstitial fluid and diffuse into blood where they are transported  to distant targets
    -Bind to target cell receptors to initiate response
    --Exert effect at very low concentrations
    --Half-life indicates how long will be active in body
  2. Target cell
    -Cell that contains a receptor for the hormone
    -Hormones only affect target cells 
    -Target cells have 2,000-100,000 receptors for a given hormone


What is the difference between the nervous system and Endocrine system in regards to communication, speed, duration, and target cells?

  1. Nervous system:
    -Communicates by sending electrical impulses to neurotransmitters which releases hormones or chemicales.
    -Impulses are sent quickly to target cells.
    -The duration is also quick and does not last long. 
    -the targets of the nervous system are muscle cells, neurons or glands
  2. Endocrine system:
    -Communicates via hormones and chemicals
    -Speed of endocirne is usuallly slow except in the case of adrenaline
    -The duration varies at it may last seconds, days, or hours.
    -Endocrine acts on almost all cells using a specific hormone to target a compatable cell

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What are the twelve glands we need to know? 

  1. Adrenal Gland
  2. Heart
  3. Hypothalamus
  4. Islets of Langerhans (spleen)
  5. Kidneys
  6. ovaries
  7. parathyroid gland
  8. Pineal gland
  9. Pituitary anterior
  10. Pituitary posterior
  11. Testes
  12. Thryoid gland


What are the twelve glands and what do they release? 

  1. Adrenal gland = epinephrine
  2. Heart = atrial natriuretic hormone
  3. Islets of Langerhans (Pancreas) = Insulin, glucogon
  4. Kidneys = erythropoietin
  5. Ovaries = estrogen, progesterone
  6. Parathyroid gland = parathyroid hormone
  7. Pineal gland = melatonin
  8. Pituitary anterior = trophic hormones
  9. Pituitary posterior = antidiuretic hormones, oxytocin
  10. Testes = testosterone
  11. Thyroid gland = thyroxine, calcitonine


What are the classifications of hormones?

  1. Amines derived from an amino acid
    -Ex: epinephrine
  2. Proteins are chains of amino acids
    -Ex; protein, insulin
  3. Steroids are lipids derived from cholesterol
    -Ex: testosterone


What is the peptide hormone synthesis? Explain its process.

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What is the difference between water and lipid soluble hormones? 

  1. Water soluble hormones
    -Hydrophilic and Lipophobic
    -Cannot pass through plasma -membranes
    -Receptors on outside surface of cells and trigger a response inside the cell
  2. Lipid soluble hormones
    -lipophilic and hydrophobic
    -Can enter target cells directly
    -Receptors usually on the inside of cells and trigger a response inside the cell


Can hydrophilic hormones cross cell membranes? If not then how? 

-Amines and protein hormones cannot cross cell membrane, so bind to receptors on cell surface
-Often make use of a 2nd messenger mechanism  to pass signal to inside of target cell:
Ex: Tyrosine kinase

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What is Steroid hormone action?

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What are the different ways of hormone interaction? 

  1. Synergistic - work together to produce an effect
  2. Permissive - one hormone makes the target cell more responsive to second hormone
  3. Antagonistic – hormones oppose each other

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What is the hypothalamus and what does it do? 

  • Integration between nervous and endocrine systems
  • Hypothalamus controls activity of pituitary gland
    Releases hormones that act on anterior pituitary
    Produces hormones stored & released from posterior pituitary 


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What does the anterior pituitary do?

Anterior pituitary releases 6 “trophic” hormones that  act on other endocrine glands to stimulate growth, development and release of hormones

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What are adrenal glands and what do they do? 

  • Sit above kidneys and function as 2 glands
  • Outer glandular cortex secretes steroid hormones
  • Inner neural medulla secretes epinephrine 

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What is the thryoid gland and what does it do? 

  • Located just below the larynx
  • Follicular cell hormones increase body metabolism
    -Regulate BMR & oxygen use
  • Parafollicular cells produce Calcitonin:
    -Lowers blood calcium
    -Inhibits breakdown of calcium from bone /deposits on bone
    -Stimulates kidneys to excrete calcium

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What is the parathyroid gland and what does it do? 

  • Embedded back of thyroid gland
  • Secrete parathyroid hormone
    -Hormone promotes rise in blood Ca2+ by acting on bones, kidneys, intestine

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What is the pancreas and what does it do? 

  • Acts as both endocrine and exocrine glands
    -Endocrine cells located in islets of Langerhans
  • Antagonistic hormones regulate blood sugar
    -Glucagon (alpha cells) increase glucose levels
    -Insulin (beta cells) lower glucose levels

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How does insulin work? 

Binds to receptors on target cells
-Vesicles with GLUT 4 carrier proteins bind to membrane
-Glucose diffuses through GLUT 4 channels
-Occurs in adipose, muscle, and the liver

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What is the Endocrine reflex pathway? 

  1. Stimulus
  2. Sensor
  3. Input signal
  4. Integrating Center
  5. Output signal (hormone in blood)
  6. Targets
  7. Response

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What is the pineal gland and what does it do? 

  • Located on roof of third ventricle in the brain
  • Secretes melatonin – regulate circadian rhythms