TEST 11

• What are the master endocrine glands?

  hypothalamus and pituitary gland
• Where does the hypothalamus receive information from


  cortex, thalamus, limbic system, autonomic nervous system (temp, thirst, hunger, sex, fight or flight) internal organs
• How many hormones are produced by the hypothalamus

  9; 7 are releasing or inhibiting 2 are for storage
• How many hormones are produced by pituitary gland

  7 and 9 are secreted (2 from storage)
• adenohypophysis and Neurohypophysis


  Anterior pituitary (75% of pitiutary gland weight) secretes FSH, LH, Prolactin, ACTH, GH, TSH, MSH

  
  

  Posterior pitutary made up of neural tissue and releases two hormones made by hypothalamus
• Describe Hypothalamic Pituitary Communication

  Neurosecretory cells in hypothalamus make hormones and package into vesicles --> send it down through axonal transport --> terminates and releases hormones into primary plexus --> hypophyseal portal system --> target tissue
• Neurosecretory cells (amount of hormones)

  5 stimulate secretion; 2 suppress secretion
• Three hormone system


  hypothalamus hormones control pituitary hormones, which control target tissue hormones. Target tissue hormones can inhibit hypothalamus
• Negative Feedback loop


  When conc. of target gland increase, AP secretion decreases
• What are the cells of the Anterior Pituitary Gland

  Somatotrophs: secrete growth hormone

  Thyrotrophs: secrete Thyroid stimulating hormone

  Gonadotrophs: secrete FSH and LH

  Lactotrophs: secrete Prolactin

  Corticotrophs: secrete ACTH, MSH
• Somatotrophs


  secrete growth hormone
• What is the role of growth hormone in metabolism? (direct and indirect)

  It directly changes metabolism by stimulating lipolysis and slowing glucose uptake. and its indirect actions include tissue growth for the liver, skeletal muscle, cartilage and bone
• What does growth hormone synthesize that helps in cell growth?

  IGF (Insulin-like Growth Factor)
• How does IGF contribute to growth and repair?

  It helps in stimulating osteoblasts and promoting growth and repair.
• When do we release more GH

  during sleep (non-REM), increased SNS activity, and amino acid, but decreased fatty acid, when we arent obese or old
• Explain GHrH mechanism


  Low glucose stimulates GHRH from hypothalamus, this then acts on somatotrophs to release hgH, raises blood glucose through metabolism, inhibits GHRH
• EXPLAIN gHIH


  High blood glucose --> releases of GHIH --> inhibts production of hGH by somatotrophs
• Acromegaly


  enlargement of the extremities; occurs only in adulthood
• Gigantism


  too much GH troughout child hood = early death
• TSH


  thyroid stimulating hormone; acts on thyroid follicular cells; stimulated by TRH; regulated by the negative feeback loop of T3 and T4
• Follicle Stimulating Hormone


  GnRH --> FSH --> forms follicles, secretes estrogen, secretes sperm

  
  

  --| inhibited by estrogen and testosterone that act on the hypothalamus
• What hormone triggers ovulation after GnRH acting on it and triggers the formation of corpus luteum??

  LH
• estrogen and progesterone


  hormones that stimulate the production of interstitial cells and testosterone while inhibiting overall GhRH
• ACTH


  CRH --> corticotrophs --> ACTH --> secrete cortisol and other glucocorticoids --| ACTH and CRH
• What is the posterior pitutary gland made of

  axon terminals and hypothalmic neurons, no 2 portal system
• Oxytocin


  A hormone released by the posterior pituitary that stimulates uterine contractions during childbirth and milk ejection during breastfeeding.
• Prolactin


  PIH or PRH --> lactotrophs produce prolactin --> milk production after birth and during pregnancy

  
  

  inhibited by suckling
• ADH (vasopressin)


  decreases urine production, decreases sweating through the sudoriferous glands, and increases blood pressure through constriction

  
  

  - inhibited by alcohol

  increased with high blood osmotic pressure

  decreased with low blood osmotic pressure (overhydration) on hypothalamic osmoreceptors
• What decreases the release of ADH

  overhydration - so low blood osmotic pressure
• Describe key parts of the pancreas?

  1% Islets + 99% acini
• Key parts of the pancreatic Islet

  Alpha cell: secrete glucagon to increase glucose release, indulge in gluconeogenesis to make more glucose

  Beta Cell: secrete insulin to lower blood glucose through uptake mechanism, increases the synthesis of glycogen, TG an proteins

  Delta Cell: releases somatostatin which is used to inhibit both alpha and beta function/ release of glucagon and insulin

  F cell: secrete pancreatic polypeptide - inhibits somatostatin, gallbladder contraction, and secretion of pancreatic digestive enzymes
• What does low blood glucose do?

  stimulates the release of glucagon

  high glucose stimulates secretion of insulin
• Glucagon


  converts glycogen to glucose, forms glucose from lactic acids
• Insulin


  speed synthesis of fatty acid, increase uptake of amino acids and increases glucsoe conversion to glycogen
• Hypoglycemia vs hyperglycemia


  Hypoglycemia (low blood sugar = inhibts insulin)

  Hyperglycemia (high blood sugar = inhibits glucagon)
• What are some of the fight or flight responses due to stressors

  1. Inc. HR

  2. Cons. blood vessels of skin

  3. dilation of lungs, heart, and brain

  4. cont. of spleen

  5. conv, of glycogen to glucos

  6. sweat

  7. dilation of air ways

  8. dec. digestive activ

  9. water retention and inc BP
• Delayed resistance response of Corticotrophs

  ACTH --> acts on adrenal gland --> gland releases cortisol --> lipolysis, gluconeogenesis, protein catabolism, reduce inflammation
• Delayed resistance Response of Somatotrophs

  Somatotrophs --> GH --> Lipolysis, Glycogenolysis
• Delayed resistance response of thyrotrophs

  TRH --> TSH (Ap) --> Thyroid: T3 (more potent) & T4 (more largely produced) increase use of glucose to produce ATP
• Corticotrophin Releasing Hormone stimulates

  ACTH release