1. Chapter 31
Endocrine Control

2. Difference between endocrine and exocrine
The endocrine system controls the body activities by producing chemical substances called ______________which are secreted by ductless glands known as __________________
Exocrine gland secrete their products into ducts or channels, that carry them either to the outside of the body or into _____________________.

3. What Are Animal Hormones?
Animal hormones: ____________________________ ________ that are secreted by __________________
Distributed by the _______________;
Typically act at ___________________from their source
Only cells with the appropriate ________________ (target cells) can respond to a specific hormone

4. Categories of Hormones
Two major categories of hormones:
______________________-derived hormones (________)

5. Categories of Hormones (cont’d.)
Amino acid-derived hormones: bind to receptors at the __________________of a target cell
Initiates __________________ signaling cascade that brings about the target cell’s response
Often results in the activation of an ___________
Example: glucagon binds to receptor; causes activation of glycogen-degrading enzyme

6. Categories of Hormones
Steroid hormones: synthesized from ____________________
Directly affects gene expression
Diffuses into a target cell (why?) and forms a hormone–receptor complex
Hormone–receptor complex: _____________________________________________________________________________________________

7. Hormone Receptor Function
Many hormones target more than one type of cell
Elicit a ________________response in each cell type
Example: antidiuretic hormone (ADH)
Affects urine formation in the ________________
Triggers smooth muscle contraction in ___________________

8. What Are the Components of the Human Endocrine System?
Endocrine glands: aggregations of epithelial cells that produce and secrete ________into the ______
Collectively make up the __________________________
Portions of the ____________system and ________ system are closely linked
Most organs respond to hormones and signals from the ________________________

9. Endocrine System
Figure 31.2 {Animated} Major glands of the human endocrine system. Other vertebrates typically have the same glands.

10. What Are the Components of the Human Endocrine System?
Table 31.1 Examples of Human Endocrine Glands, Their Hormones, and Hormone Actions

11. How Does the Hypothalamus Interact With the Pituitary Gland?
Hypothalamus: main center that controls the ____________________________________
Lies deep inside the forebrain and connects with the ____________________________
anterior
lobe of
pituitary
posterior
hypothalamus

12. Posterior Pituitary Function
Neurosecretory cells in the hypothalamus synthesize _____________ hormones
These hormones are transported along _________in the posterior pituitary
An action potential triggers the release of hormone into the _____________
Posterior pituitary releases two hormones:
____________________________(____)
____________________________

13. pituitary function
Figure 31.4 {Animated} Pituitary function.

14. Anterior Pituitary Function
The anterior pituitary makes ___________ hormones and secretes them in response to hormones from the __________________________
Anterior pituitary hormones:
________________________________________________
_________________________________________________

15. Hormonal Growth Disorders
Growth hormone production surges during _____________, causing a growth spurt, then declines with __________
_______secretion of growth hormone during childhood leads to pituitary ___________________
___________growth hormone during childhood can cause pituitary _______________

16. What Is the Role of the Pineal Gland?
Pineal gland: lies deep inside the brain; secretes the hormone ___________under low-light or dark conditions
____________: _________________________________________

17. What Are the Thyroid and Parathyroid Glands?
Thyroid gland: endocrine gland located in the base of the neck
Thyroid hormone (triiodothyronine and thyroxine): increases metabolic activity
The anterior pituitary gland and hypothalamus regulate thyroid hormone secretion
Decline in thyroid hormone causes hypothalamus to secrete thyroid-releasing hormone (TRH)
TRH causes the anterior pituitary to secrete thyroid-stimulating hormone (TSH)
TSH stimulates secretion of thyroid hormone

18. What Are the Thyroid and Parathyroid Glands?
STIMULUS
RESPONSE
Hypothalamus
TH declines
below a set
point 1
TRH 4
Anterior Pituitary
TSH 2
Figure 31.6 Control of thyroid hormone (TH) secretion.
Thyroid Gland 3
TH secretion increases
and metabolic rate rises.

19. Hormonal Regulation of Blood Calcium Level
There are four parathyroid glands on the thyroid’s _____________________surface
Parathyroid hormone (PTH): ______________________ _________________________________________________
Calcitonin: ______________________________________ _________________________________________________; opposes the actions of PTH

20. What Are the Roles of the Adrenal Glands?
Adrenal gland: endocrine gland that is located atop the __________________
Adrenal cortex: __________________________________
Examples:
Aldosterone: acts in _______________and makes urine more concentrated
Cortisol: affects ______________and ______________________
Adrenal medulla: responds to stimulation by releasing __________________and ______________into the blood
Brings on ____________________________

21. What Are the Roles of the Adrenal Glands? (cont’d.)
STIMULUS
RESPONSE
Blood level of cortisol declines.
Hypothalamus 1
CRH 4
Anterior Pituitary
adrenal cortex
Rise of cortisol level in the blood inhibits the secretion of CRH and ACTH. 2
ACTH
adrenal medulla
Adrenal Cortex 3
Cortisol secretion increases and has the following effects:
Figure 31.8 Control of cortisol secretion.
Cellular uptake of glucose from blood slows in many tissues, especially muscles (but not in the brain). Protein breakdown accelerates, especially in muscles.
Some of the amino acids freed by this process get converted
to glucose.
Fats in adipose tissue are degraded to fatty acids and enter blood as an alternative energy source, indirectly adrenal
cortex adrenal medulla kidney conserving glucose for the brain.
kidney

22. Hormones, Stress, and Health
Long-term elevation of cortisol is unhealthy (example: Cushing’s syndrome):
Interferes with _____________, _____________, and ______________function
Raises the risk of _________________________________
Abnormally low levels of cortisol (example: Addison’s disease)
___________, _____________, ______________, and _____________________________________

23. What Are Sex Hormones?
Sex hormones: ____________hormones produced by the _________________
Essential to ___________________________function
Influence secondary sexual characteristics
______________________________________________________________________________________________________________

24. What Are Sex Hormones?
Testosterone: responsible for development of __________________________and secondary sexual characteristics
Estrogens: function in ________________and cause development of ______________secondary sexual characteristics
Progesterone: prepares a female body for ______________and helps ______________________

25. What Are Sex Hormones?
Figure Control of sex hormone secretion.

26. How Does the Pancreas Regulate Blood Sugar?
Pancreas: lies in the ______________cavity, behind the _____________
Exocrine cells: secrete _________________________ into the small intestine
Endocrine cells: grouped in clusters called pancreatic islets (e.g., ______cells and _______cells)

27. How Does the Pancreas Regulate Blood Sugar? (cont’d.)
Beta cells secrete _________when blood glucose levels ___________
Insulin causes its target cells to ___________________ _________________________________
Encourages synthesis of fats and proteins and inhibits their breakdown
_________________________________________
Alpha cells secrete ___________when blood glucose levels ____________
Glucagon binds to receptors on liver cells: activates enzymes that break __________ into ________subunits
___________________________________________

28. Hormones and glucose metabolism
Figure {Animated} Above, the location of the pancreas. Right, how cells that secrete insulin and glucagon work antagonistically to adjust the level of glucose in the blood.

29. How Does the Pancreas Regulate Blood Sugar?
The regulation of blood glucose is disrupted in diabetes mellitus
Type 1 diabetes: ______________________________ _____________________________________________
Symptoms usually appear in ____________and ______________
Type 2 diabetes: ______________________________ ______________________________
Symptoms typically start in ___________________

30. How Does the Pancreas Regulate Blood Sugar? (cont’d.)
Insulin pump. This device delivers insulin into a diabetic’s body to maintain blood glucose within normal levels.
Figure Insulin pump. This device delivers insulin into a diabetic’s body to maintain blood glucose within normal levels.

31. Do Invertebrates Have Hormones?
Some components of the endocrine system occur in invertebrates
Example: __________, ___________, and __________ make ____________hormones
Invertebrates do not have the same glands as vertebrates do, but they produce the homologous hormones in other glands
Example: octopi produce _________, __________, and ___________ in a gland near their eye

32. Do Invertebrates Have Hormones?
Hormone-signaling systems unique to invertebrates have also evolved
Example: a hormone unique to arthropods called ecdysone controls molting (periodic shedding of the exoskeleton)