LectureDate _______

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Lecture Date _______

• Chapter 45
• Chemical Signals in Animals

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Regulatory systems

• Hormone
• chemical signal secreted into body fluids (blood)
  communicating regulatory messages
• Target cells
• body cells that respond to hormones
• Endocrine system/glands
• hormone secreting system/glands (ductless)
  exocrine glands secrete chemicals (sweat, mucus,
  enzymes) through ducts
• Neurosecretory cells
• actual cells that secrete hormones
• Feedback mechanisms
• negative and positive

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Local regulators cells adjacent to or near
point of secretion

• Growth factors
• proteins for cell proliferation
• Nitric oxide (NO)
• neurotransmitter cell destruction vessel
  dilation
• Prostaglandins
• modified fatty acids secreted by placenta and
  immune system also found in semen

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Mode of Action Chemical Signaling

• 1- Plasma membrane reception
• signal-transduction pathways (neurotransmitters,
  growth factors, most hormones)
• 2- Cell nucleus reception
• steroid hormones, thyroid hormones, some local
  regulators

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Vertebrate Endocrine System

• Tropic hormones
• a hormone that has another endocrine gland as a
  target
• Hypothalamuspituitary
• Pituitary gland
• Pineal gland
• Thyroid gland
• Parathyroid glands
• Thymus
• Adrenal glands
• Pancreas
• Gonads (ovary, testis)

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The hypothalamus pituitary, I

• Releasing and inhibiting hormones
• Anterior pituitary
• Growth (GH)bones
• gigantism/dwarfism
• acromegaly
• Prolactin (PRL)mammary glands milk production
• Follicle-stimulating (FSH)
• Luteinizing (LH) ovaries/testes
• Thyroid-stimulating (TSH) thyroid
• Adrenocorticotropic (ACTH) adrenal cortex
• Melanocyte-stimulating (MSH)
• Endorphinsnatural opiates brain pain
  receptors

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The pituitary, II

• The posterior pituitary
• Oxytocin
• uterine and mammary gland cell contraction
• Antidiuretic (ADH)
• retention of water by kidneys

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The pineal, thyroid, parathyroid

• Melatonin
• pineal gland biological rhythms
• Thyroid hormones
• Calcitonin - lowers blood calcium
• Thyroxine - metabolic processes
• Parathyroid (PTH)
• raises blood calcium

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The pancreas

• Islets of Langerhans
• Alpha cells
• Glucagon - raises blood glucose levels
• Beta cells
• Insulin - lowers blood glucose levels
• Type I diabetes mellitus (insulin-dependent
  autoimmune disorder)
• Type II diabetes mellitus (non-insulin-dependent
  reduced responsiveness in insulin targets)

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The adrenal glands

• Adrenal medulla (catecholamines)
• epinephrine norepinephrine - increase basal
  metabolic rate (blood glucose and pressure)
• Adrenal cortex (corticosteroids)
• glucocorticoids (cortisol) - raise blood glucose
• mineralocorticoids (aldosterone) - reabsorption
  of Na and K

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The gonads

• Steroid hormones precursor is cholesterol
• Androgens (testosterone)
• sperm formation male secondary sex
  characteristics gonadotropin
• Estrogens (estradiol)
• uterine lining growth female secondary sex
  characteristics gonadotropin
• Progestins (progesterone)
• uterine lining growth