anatmoy test

• The general functions of the endocrine system is

  Metabolism

  Development

  Reproduction

  Homeostasis
• Hormones are chemical messengers that are produced by glands and travel in the bloodstream to target organs
• Paracrine effectors are Chemical messengers produced by a cell diffuses though interstitial fluid where it influences an adjacent cell.
• Autocrine effectors are Chemical messengers produced by a cell acts on the cell of origin
• Neurotransmitters are Chemical messengers that effect communication between neurons, or between neurons and target cells or release of neurohormone into the blood
• Exocrine Effectors are Chemical messengers produced by a cell/gland and released via a duct into an adjacent region
• There are 2 major classes of Hormones Proteins and Steroids
• the sub classes of Protiens are

  Proteins: (growth hormone, insulin, corticotropin)

  Peptides: (oxytocin vasopressin)

  Amines: (dopamine, melatonin, epinephrine)
• the subclasses of Steroids are

  adrenocortical hormones (glucocorticoids (cortisol) mineralcorticoids)

  sex hormones (estrogen, progesterone, androgens)
• Steroids are Lipophilic meaning they can cross membranes
• Peptides and Amines are hydrophillic meaning they can NOT cross the membrane
• Protien hormones are stored in granules and will be released using exocytosis
• Protein hormones are carried in plasma and bind to receptors on target cells
• Steroid hormones are released as soon as they are made as the cannot be contained in vesicles
• there are 4 ways the hormone singals controlled

  Negative feedback loop

  Positive feedback loop

  Circadian rhythm

  Direct stimulation from the nervous system
• The endocrine glands are

  1 pituitary gland

  1 thymus

  1 pineal gland

  1 thyroid gland

  4 parathyroid glands

  2 adrenal glands

  1 pancreas

  2 gonads
• Pituitary gland

  located attached the hypothalamus found in the brain

  2 sides the posterior and the anterior
• The posterior pituitary gland releases ADH (antidiuretic hormone)

  Oxytocin
• The hypothalamus controls the pituitary glands
• The Posterior Pituitary Gland releases hormones when stimulated by the hypothalamus due to modified neurons
• Oxytocin

  the main effect is contraction

  but it is also the "love/cuddle" hormone it is relaesed during bonding
• Vasopressin

  also known as ADH

  the primary function is water conservation
• Diabetes Insipidus

  is a disorder of water metabolism

  symptoms are: Polyuria( Increased urination), Nocturia (need to pee at night) , incontinence, dilute urine , dehydration and weight loss
• The two cuases of Diabetes Insipidus is

  Central DI: characterized by lack of circulating VP

  Nephrogenic DI: inability of renal tubule to respond to VP
• The anterior Pituary gland releases

  FSH (follicle-stimulating hormone)

  LH (Luteinizing hormone)

  ACTH (adrenocorticotropic hormone)

  TSH (thyroid stimulating hormone)

  PRL (Prolactin)

  GH (growth hormone)

  MSH (melanocyte stimulating hormone)
• The thyroid gland is located on either side of the larynx it produces T3 , T4 and Calcitonin hormones
• The thyroid gland functions are

  Metabolic regulation

  Calcium regulation
• Follicular cells are part of thyroid tissue they contain the thyroid hormone
• Parafollicular cells secrete calcitonin which inhibits calcium release from the bone
• the half life of T4 is 6-7 days
• the half life of T3 is 24 hours
• T4 has tighter binding to plasma proteins then T3
• there are 6 effects of Thyroid hormone

  1. Calorigenic effects
  2. Carbohydrate metabolism
  3. Protein metabolism
  4. Lipid metabolism
  5. Effects on CNS
  6. Cardiovascular effects
• Calorigenic effect of the thyroid hormone

  it is the primary way for the body to determine the basal metabolic rate

  It allows the animal to generate heat and maintain a constant body temp

  when the body is exposed to cold the thyroid hormone production increases
• Thyroid hormone is responsible for maintaining normal contractile activity of cardiac muscle
• Thyroid Stimulating Hormone is the most important regulator of thyroid activity
• TSH secretion is regulated by T3 and T4
• Goiter is an enlargement of the thyroid gland that occurs as the result of the inability to secrete adequate amounts of TH caused by a deficiency of iodine or by progoitrin
• Hypothyroidism is most common in dogs signs are lethargy obesity tail alopecia dull coat and a dry coat
• Hyperthyroidism is most common in cats signs are increased heart rate, increased thirst, increased urination