Endocrine (regulatory) System

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Endocrine (regulatory) System

• Chapter 45

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Introductory Questions 3

• Name the nine major endocrine glands found in the
  body. Which one ins called the master gland?
• Name three major local regulators that act on
  nearby target cells. (pgs. 947-948)
• Name three key molecules that play a role in the
  signal transduction pathway (typical reactions in
  the endocrine system).
• How is the anterior part of the pituitary gland
  different from the posterior part? Name the
  hormones secreted from each area. Which region
  secretes fewer types of hormones?
• Using the table on pg. 949, name the hormone(s)
  that
• -Raises blood-calcium levels
• -maintains metabolic processes

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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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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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Hypothalamus Pituitary Gland

• Releasing and inhibiting hormones
• Anterior pituitary
• Growth (GH)bones vgigantism/dwarfism
  vacromegaly
• 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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Hypothalamus Pituitary Gland
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Posterior Region of the Pituitary Gland

• 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

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Ch. 45 Endocrine System Systems in Balance

• What organism does Dr. Hunt Dr. Fry use to
  discuss and show how a toxic chemical affects
  hormone balance?
• How is a hormone defined in the video and how do
  these chemicals control metabolic activities in
  animals?
• What two structures in the brain does Dr.
  Catherine Rivier explore that relates to stress?
• How is the endocrine system similar to the
  nervous system? How do they interact?
• In the final segment name two methods scientists
  use to study the endocrine system and the effects
  of hormones?
• Important Text Pages Pg.
• Write the title for each segment and FIVE
  statements for each segment.

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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

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Homeostasis Osmoregulation

• Chapter

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Let Sleeping Bears Lie

• Bears dont technically hibernate
• They do enter a dormant state, when their body
  temperature drops by several degrees
• Bears are endotherms
• Endothermic animals derive most of their body
  heat from metabolism
• Ectothermic animals warm themselves mainly by
  absorbing heat from their surroundings

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• Dormant bears have internal homeostatic
  mechanisms that compensate for fluctuations in
  the external environment

• Thermoregulation maintains the body temperature
  within a tolerable range
• Osmoregulation controls the gain and loss of
  water and dissolved solutes
• Excretion is the disposal of metabolic wastes

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Heat is gained or lost in four ways

• Body temperature regulation requires adjustment
  to heat gained from or lost to an animals
  environment

Convection
Radiation
Evaporation
Conduction
Figure 25.1
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• Hormonal changes may increase heat production by
  raising the metabolic rate

• Fur and feathers help the body retain heat
• Shivering, as these honeybees are doing, also
  increases metabolic heat production

Figure 25.2A
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The liver is vital in homeostasis

• It assists the kidneys by
• making urea from ammonia
• breaking down toxic chemicals

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Homeostasis regulation of internal environment

• Thermoregulation internal temperature
• Osmoregulation solute and water balance
• Excretion nitrogen containing waste

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Regulation of body temperature

• Thermoregulation
• 4 physical processes
• Conductiontransfer of heat between molecules of
  body and environment
• Convectiontransfer of heat as water/air move
  across body surface
• Radiationtransfer of heat produced by organisms
• Evaporationloss of heat from liquid to
  gas
• Sources of body heat
• Ectothermic determined by environment
• Endothermic high metabolic rate generates high
  body heat

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Regulation during environmental extremes

• Torpor low activity decrease in metabolic
  rate
• 1- Hibernation long term or winter torpor
  (winter cold and food scarcity) bears, squirrels
• 2- Estivation short term or summer
  torpor (high temperatures and water scarcity)
  fish, amphibians, reptiles
• Both often triggered by length of daylight