AP Biology, Chapter 45
Chemical Signals in Animals

SUMMARY
INTRODUCTION

AN INTRODUCTION TO REGULATORY SYSTEMS
	Introduction
	1. Define hormone.
	a. Chemicals released into the blood by endocrine glands
	b. Affect the functions of mainly distant target organs
2. What types of changes do hormones cause in their target tissues?
a. Changes in membrane permeability or polarity
b. Changes in gene expression 
c. Activation or inactivation of enzymes
d. Stimulation of mitosis
3. Describe negative feedback as the mechanism for regulating blood hormone levels. 
a.  Rising hormone levels inhibit further hormone release 
	The endocrine system and the nervous system are structurally, chemically and 
	functionally related
4. Differentiate hormonal, humoral, and neural stimulus of endocrine glands.
a. Hormonal: a hormone may stimulate the release of another hormone
b. Humoral: changing blood levels of ions or metabolites may stimulate
c. Neural: nerve stimulation may cause hormone release 
	Invertebrate regulatory systems clearly illustrate endocrine and nervous system 
	interactions

CHEMICAL SIGNALS AND THEIR MODES OF ACTION
	Introduction
	A variety of l0cal regulators affect neighboring target cells
5. Differentiate three major chemical types of hormones. 
a. Amino-acid-based = proteins or peptides
b. Steroids made from cholesterol
c. Prostaglandins made from the fatty acid arachidonic acid
	Chemical signals bind to specific receptor proteins within target cells or on their 
	surface
	Most chemical signals bind to plasma membrane proteins, initiating signal 
	transduction pathways
6. Differentiate the trigger interactions of steroid and nonsteroid hormones with their target cells.
a. Steroid
	i. Diffuse into the nucleus
	ii. Bind to receptor protein
	iii. Activates specific transcription
b. Nonsteroid
i. Bind to plasma membrane receptor
	ii. Activates adenylate cyclase to make cAMP
				iii. cAMP alters cell function	
	Steroid hormones, thyroid hormones, and some local regulators enter target cells and 
	bind with intracellular receptors

THE VERTEBRATE ENDOCRINE SYSTEM
	Introduction
	The hypothalamus and pituitary integrate many functions of the vertebrate endocrine 
	System
		7. List the hormones the anterior pituitary produces and their actions. 
			a. Growth hormone: stimulates growth of bone and muscle  
			b. Prolactin: stimulates milk production, unknown action in males 
			c. ACTH: stimulates adrenal cortex
			d. Thyrotropic hormone: stimulates throid gland 
			e. FSH: stimulates egg and follicle maturation, sperm development  
			f. LH: triggers ovulation, development of follicle into corpus luteum, stimulates 
			testosterone production in males
		8. Why is the anterior pituitary referred to as the "master endocrine gland"? 
			a. Controls the activity of so many other endocrine glands 
		9. Describe two ways the hypothalamus controls the function of the pituitary. 
a. Releasing and inhibiting hormones delivered by the portal circulation 
	b. Hormones made in the hypothalamus are stored in the posterior pituitary
10. List the hormones the posterior pituitary releases and their actions. 	
	a. Oxytocin: stimulates uterine contractions, milk ejection 
	b. ADH: stimulates water uptake in the kidneys 
	The pineal gland is involved in biorhythms
		11. Identify the major hormone produced by the pineal gland and its actions.
a. Melatonin regulates circadian rhythm and delays sexual maturation
	Thyroid hormones function in development, bioenergetics, and homeostasis
12. List the hormones the thyroid gland produces and their actions.
	a. Thyroxine and triiodothyronine control the metabolism of glucose
	b. Calcitonin decreases blood calcium
13. Describe the development of a goiter.
a. Insufficient dietary iodine required to make thyroid hormone
b. Thyroid enlarges attempting to make more thyroid hormone
	Parathyroid hormone and calcitonin balance blood calcium
14. List the hormones the parathyroid gland produces and their actions.
		 	a. PTH increases blood calcium
	Endocrine tissues of the pancreas secrete insulin and glucagon, antagonistic 
	hormones that regulate blood glucose
	15. List the hormones the pancreatic islet cells produce and their actions.
a. Insulin lowers blood sugar by stimulating uptake and storage
b. Glucagon raises blood sugar by stimulating glycogen breakdown
		16. Rationalize the three cardinal signs of diabetes.
			a. Polyuria: excess urine to flush excess glucose and ketones
			b. Polydipsia: excess thirst from water loss
			c. Polyphagia: excess eating to make up for inability to use glucose
		17. Differentiate type I and type II diabetes. 
			a. Type I (juvenile-onset): autoimmune destruction of islet cells, no insulin
			b. Type II (adult-onset): lack of response to insulin
	The adrenal medulla and adrenal cortex help the body manage stress
		18. List major groups of hormones the adrenal cortex produces and their actions. 
a. Mineralcorticoids regulate blood sodium, potassium, and water
b. Glucocorticoids increase blood glucose and are anti-inflammatory
c. Sex hormones stimulate secondary sexual characteristics
19. List the hormones the adrenal medulla produces and their actions. 
	a. Epinephrine and norepinephrine give generalized sympathetic stimulation
		20. Differentiate the body's response to short-term and long-term stress. 
			a. Short-term
				i. Adrenal medulla releases catecholamines
				ii. Increase heart rate and blood glucose
			b. Long-term
				i. Adrenal cortex releases more mineral- and glucocorticoids
				ii. Retain sodium and water
				iii. Mobilize proteins and fats, suppress immune system

	Gonadal steroids regulate growth, development, reproductive cycles, and sexual 
	behavior
	21. List the hormones produced by the ovaries and their actions. 
		a. Estrogens stimulate sexual development, help prepare uterus for pregnancy
		b. Progesterone helps prepare uterus for pregnancy, maintains pregnancy
	22. Identify the major hormone produced by the testes and its action. 
	a, Testosterone stimulates sexual development and maintains sperm production