CHAPTER 26: CHEMICAL REGULATION

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CHAPTER 26 CHEMICAL REGULATION
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OBJECTIVES

• HOW DO HORMONES DIFFER FROM NERVE SIGNALS?
• WHAT IS HOMEOSTASIS?
• HOW ARE WATER SOLUBLE AND LIPID SOLUBLE HORMONES
  DIFFERENT?
• KNOW THE BASIC FUNCTION OF THE ENDOCRINE GLANDS
• THYROID, PANCREAS, ADRENAL GLANDS, HYPOTHALMUS,
  PITUITARY AND SEX GLANDS

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OVERVIEW

• CHEMICAL SIGNALS COORDINATE BODY FUNCTIONS
• HORMONES
• PRODUCED BY THE ENDOCRINE SYSTEM
• HORMONAL REGULATION OF OTHER FUNCTIONS AND
  SYSTEMS
• LINKS BETWEEN THE ENDOCRINE AND THE NERVOUS
  SYSTEM

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TESTOSTERONE

• EXAMPLE OF ONE HORMONE
• DEVELOPMENT OF MALE REPRODUCTIVE ANATOMY AND
  SECONDARY SEX CHARACTERISTICS
• FACIAL HAIR
• DOES IT ALSO PROMOTE MALE AGGRESSIVE BEHAVIOR?
• ARE XYY MALES MORE AGGRESSIVE THAN XY MALES?

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HORMONES

• CHEMICAL SIGNALS
• HAVE MULTIPLE EFFECTS IN THE BODY TRAVEL
  THROUGH THE BLOODSTREAM
• COORDINATE ACTIVITIES IN DIFFERENT PARTS OF THE
  BODY
• REGULATE ENERGY USE, METABOLISM AND GROWTH

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HOMEOSTASIS

• HOW CHEMICAL SIGNALS MAINTAIN AN ANIMAL BODYS
  DYNAMIC STEADY STATE
• THE PRIMARY PURPOSE OF THE ENDOCRINE SYSTEM IS TO
  MAINTAIN A RELATIVELY CONSTANT INTERNAL
  ENVIRONMENT

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CHEMICAL SIGNALS COORDINATE BODY FUNCTIONS

• HORMONE
• CHEMICAL SIGNAL THAT IS SECRETED INTO THE
  CIRCULATORY SYSTEM (BLOOD) AND COMMUNICATES
  REGULATORY MESSAGES TO MANY PARTS OF THE BODY
• SECRETED BY ENDOCRINE GLANDS PART OF THE
  ENDOCRINE SYSTEM

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HORMONES TRAVEL FROM THE ENDOCRINE GLANDS TO
THEIR TARGETS THROUGH THE BLOOD

• HORMONES LONG DISTANCE CHEMICAL REGULATORS THE
  RESPONSE IS SLOW BUT LONGLASTING

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SOME CHEMICAL SIGNALS AFFECT ONLY NEARBY CELLS
AND OCCUR RAPIDLY

• EXAMPLE NEUROTRANSMITTERS

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DIFFERENT CLASSES OF HORMONES

• WATER SOLUBLE
• PROTEINS AND PEPTIDES
• AMINES DERIVED FROM AMINO ACIDS
• LIPID SOLUBLE
• STEROIDS

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SIGNALLING INVOLVES THREE KEY EVENTS

• RECEPTION
• HORMONE BINDS TO THE RECEPTOR PROTEIN
• SOMETIMES THE RECEPTOR IS EXTERNAL AND SOMETIMES
  INTERNAL
• SPECIFIC BINDING LIKE ANTIGEN/ANTIBODY BINDING
• TRIGGERS SIGNAL TRANSDUCTION
• SIGNAL TRANSDUCTION
• CERTAIN RELAY MOLECULES STIMULATED THAT RESULT IN
  SOME RESPONSE
• RESPONSE

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WATER SOLUBLETHE RECEPTOR IS ON THE OUTSIDE OF
THE TARGET CELL
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LIPID SOLUBLETHE RECEPTOR IS INSIDE THE TARGET
CELL
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THERE ARE MANY ENDOCRINE GLANDS THAT PRODUCE MANY
DIFFERENT HORMONES
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THE HYPOTHALMUS CONNECTS THE NERVOUS AND
ENDOCRINE SYSTEMS

• HORMONAL SIGNALS FROM THE HYPOTHALMUS STIMULATES
  THE PITUITARY GLAND
• THE PITUITARY THEN SEND SIGNALS TO OTHER GLANDS

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HORMONES OF THE POSTERIOR PITUITARY
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HORMONES OF THE ANTERIOR PITUITARY
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THE THYROID REGULATES DEVELOPMENT AND METABOLISM

• HELP MAINTAIN HOMEOSTATIC FUNCTIONS
• HELP MAINTAIN NORMAL BLOOD PRESSURE, HEART
  RATE, MUSCLE TONE, DIGESTIVE AND REPRODUCTIVE
  FUNCTION
• PRODUCES TWO MAIN HORMONES THAT CONTAIN IODINE
• T3 TRIIODOTHYRONINE
• T4 - THYROXINE

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PROBLEM WITH THYROID HORMONES CAN CAUSE DISEASES

• HYPERTHYROIDISM
• OVERHEAT, SWEAT, HIGH BLOOD PRESSURE, LOSE WEIGHT
• GRAVES DISEASE
• HYPOTHYROIDISM
• WEIGHT GAIN, LETHARGY, INTOLERANCE TO COLD
• INSUFFICEINT IODINE CAUSES GOITER ENLARGEMENT
  OF THE THYROID

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HORMONES FROM THE THYROID AND PARATHYROID
MAINTAIN CALCIUM HOMEOSTASIS

• CALCIUM IS IMPORTANT IN MANY CELL PROCESSES
• NERVE TRANSMISSION
• MUSCLE CONTRACTION
• BLOOD CLOTTING
• TRANSPORTING MOLECULES ACROSS MEMBRANES

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PANCREATIC HORMONES MANAGE CELLULAR FUEL GLUCOSE

• TWO IMPORTANT HORMONES
• INSULIN AND GLUCAGON ACT ANTAGONISITICALLY
• INSULIN DECREASES GLUCOSE LEVELS
• GLUCAGON INCREASES GLUCOSE LEVELS

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DIABETES MELLITUS

• PANCREAS DOES NOT PRODUCE INSULIN OR BODY DOES
  NOT RESPOND TO INSULIN
• GLUCOSE LEVELS ARE INCREASED

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TWO TYPES OF DIABETES

• TYPE I
• INSULIN DEPENDENT DIABETES
• JUVENILE FORM
• AUTOIMMUNE DISEASE
• PERSONS OWN T CELLS ATTACK AND DESTROY THEIR OWN
  PANCREATIC B CELLS CELLS THAT SECRETE INSULIN
• PATIENTS RECEIVE INSULIN INJECTIONS

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NON-INSULIN DEPENDENT DIABETES (TYPE II)

• INSULIN IS PRODUCED
• BODY CELLS FAIL TO RESPOND TO INSULIN
• RECEPTORS ARE NOT FUNCTIONING PROPERLY
• ASSOCIATED WITH OBESITY
• TREAT BY MANAGING WEIGHT AND EXERCISING

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ADRENAL GLAND HELPS THE BODY RESPOND TO STRESS

• ADRENAL MEDULLA
• SHORT TERM RESPONSES TO STRESS
• EPINEPHRINE AND NOREPINEPHRINE
• ADRENAL CORTEX
• LONG TERM RESPONSES TO STRESS
• STEROID HORMONES
• MINERALCORTICOIDS
• GLUCOCORTICOIDS

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STEROIDS AND SPORTS

• WHAT ARE SOME INSTANCES WHERE ATHLETES ARE
  BOOSTING THEIR PERFORMANCE BY TAKING STEROIDS?

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GONADS SECRETE SEX HORMONES

• ESTROGENS
• MAINTAIN THE FEMALE REPRODUCTIVE SYSTEM
• PROGESTINS
• PROGESTERONE
• PREPARE THE UTERUS TO SUPPORT THE EMBRYO
• ANDROGENS
• DEVELOPMENT AND MAINTENANCE OF THE MALE
  REPRODUCTIVE SYSTEM
• TESTOSTERONE