Endocrine Control

1
Endocrine Control

• Starr/Taggarts
• Biology
• The Unity and Diversity of Life, 9e
• Chapter 37

2
Key Concepts

• Hormones integrate activities of individual cells
  in ways that benefit the whole body
• Only the cells with receptors for specific
  hormones are the targets
• Hormones affect the target cells in various
  different ways

3
Key Concepts

• Hormones help the body adjust to short and
  long-term adjustments in cell activities
• The hypothalamus and pituitary gland interact to
  coordinate the activities of endocrine glands
• Other factors besides hormones trigger hormone
  secretions

4
Hormones and Other Signaling Molecules

• Hormones
• Secretory products of endocrine glands
• Dispersed via the blood
• Target sites throughout the body
• Neurotransmitters
• Released from axons
• Local signaling molecules
• Local regions
• Pheromones
• Exocrine secretions

5
Neural - Endocrine Control Center

• Pituitary gland interacts with the hypothalamus

6
The Human Endocrine System
7
Signaling Mechanisms

• Steroids
• Testosterone, Estrogens, Progestins, Cortisol,
  Thyroid, Vitamin D, Aldosterone
• Peptides
• Glucagon, ADH, Oxytocin, TRH
• Proteins
• Insulin, Somatotropin, Prolactin
• Glycoproteins
• FSH, LH, TSH

8
The Hypothalamus and Pituitary Gland

• Hypothalamus
• Monitors internal activities and organs
• Pituitary Gland
• Posterior Lobe
• ADH
• Oxytocin

9
The Hypothalamus and Pituitary Gland

• Pituitary Gland
• Anterior lobe
• ACTH, TSH, FSH, LH, PRL, GH
• Capillary beds from the hypothalamus

10
Examples of Abnormal Pituitary Output

• Gigantism
• Excess GH in childhood
• Dwarfism
• Underproduction of GH
• Diabetes insipidus
• Diminished ADH secretion
• Acromegaly
• Excess GH in adulthood

11
Sources and Hormones

• Adrenal Cortex Glucocorticoids
• Adrenal medulla Epinephrine Norepinephrine
• Thyroid Thyroxine Calcitonin
• Parathyroid PTH
• Gonads
• Testes Androgens
• Ovaries Estrogen Progesterone

12
Sources and Hormones

• Pancreas Insulin Glucagon
  Somatostatin
• Thymus Thymosins
• Pineal Melatonin
• Stomach Gastrin
• Small intestine Gastrin Secretin

13
Sources and Hormones

• Liver Somatomedins
• Kidneys Erythropoietin Angiotensin
  Calcitriol
• Heart Atrial natriuretic hormone

14
Feedback Control of Hormonal Secretions

• Negative Feedback
• Some positive feedback
• Labor and delivery

15
INSULIN
Many cells, especially muscle cells, take up
glucose and use it as an energy source or
convert it to glycogen.
Beta cells of pancreas release insulin into blood.
Liver converts glucose to glycogen, fats,
proteins.
Blood glucose levels decline to a set point
stimulus calling for insulin diminishes.
Stimulus Glucose is absorbed following a meal.
Stimulus Cells use or store glucose between
meals.
Blood glucose levels increase to a set point
stimulus calling for glucagon diminishes.
Alpha cells of pancreas release glucagon into
blood.
Liver converts glycogen to glucose, stops
synthesizing glycogen.
GLUCAGON
16
The Thyroid

• Thyroxine
• Iodine
• TSH from the anterior pituitary gland stimulates
  thyroid
• Hypothyroidism
• Goiter
• Hyperthyroidism

17
Feedback Control of the Gonads

• Loop to the hypothalamus and pituitary gland from
  the ovaries

18
Secretions from Parathyroid Glands

• PTH
• Regulates calcium levels in blood
• Low calcium blood levels
  ----gt Parathyroid secretes PTH

19
Secretions from Pancreatic Islets

• Alpha cells
• Glucagon
• Glycogen conversion to glucose
• Beta cells
• Insulin
• Glucose uptake by cells
• Delta
• Somatostatin
• Control of digestion

20
Diabetes

• Type I
• Autoimmune response against insulin secreting
  cells
• Childhood Diabetes

• Type II
• Less production of insulin
• Target cells respond less with age
• Adult Diabetes

21
Hormonal Responses to Environmental Cues

• Pineal Gland
• Melatonin
• Levels influence hormones and gonads
• Influence on sleep/wake cycles
• Dark
• Increase in melatonin
• Depressed activity
• Winter Blues

22
In Conclusion

• Cells exchange substances with the internal
  environment
• Integration of cell activities requires the
  stimulatory or inhibitory effects of molecules
• Those molecules can be hormones,
  neurotransmitters, and pheromones

23
In Conclusion

• Certain steroids, peptides, proteins, and
  glycoproteins are hormones
• Hormones exert their physiological effects
  through interactions with specific protein
  receptors
• The posterior pituitary gland stores and secretes
  ADH and oxytocin

24
In Conclusion

• The anterior pituitary gland makes and secretes
  hormones which target organs
• The vertebrate body has other sources of hormones
  throughout the body
• Hormone interactions, feedback mechanisms,
  receptors on target cells, and the environment
  influence hormone secretions
• developed by M. Roig