1. Chapter 45: Endocrine System

2. Learning Targets
I can idnetify and explain the role that hormones have in homeostatic pathways.
I can diagram how hormones bind to tarfet receptors and trigger specific pathways.
I can explain one hormone that displays positive feedback and one that displays negative feedback.
I can explain how steriod and peptide hormones differ as ligands in signal transduction pathways.
I can explain the significance of having antagonistic hormones to maintain homeostasis.

3. Steroid vs. water soluble hormones

4. Short-term stress response and the adrenal medulla (b)
Figure 45.21
(a)
Short-term stress response and the adrenal medulla
(b)
Long-term stress response and the adrenal cortex
Stress
Nerve signals
Hypothalamus
Spinal cord (cross section)
Releasing hormone
Nerve cell
Anterior pituitary
Blood vessel
Nerve cell
ACTH
Adrenal medulla secretes epinephrine and norepinephrine.
Adrenal cortex secretes mineralo- corticoids and glucocorticoids.
Adrenal gland
Kidney
Figure Stress and the adrenal gland.
Effects of epinephrine and norepinephrine:
Effects of mineralocorticoids:
Effects of glucocorticoids:
Glycogen broken down to glucose;
increased blood glucose
• Retention of sodium ions and water by kidneys
• Proteins and fats broken down and converted to glucose, leading to increased blood glucose
Increased blood pressure
Increased breathing rate
Increased metabolic rate
• Increased blood volume and blood pressure
Change in blood flow patterns, leading to increased alertness and decreased digestive, excretory, and reproductive system activity
• Partial suppression of immune system

5. G protein-coupled receptor GTP
Figure
Epinephrine
Adenylyl cyclase
G protein
G protein-coupled receptor
GTP
ATP
Second messenger
cAMP
Figure 45.7 Cell-surface hormone receptors trigger signal transduction.
Protein kinase A
Inhibition of glycogen synthesis
Promotion of glycogen breakdown

6. Same receptors but different intracellular proteins (not shown)
Figure 45.9
Same receptors but different intracellular proteins (not shown)
Different receptors
Different cellular responses
Different cellular responses
Epinephrine
Epinephrine
Epinephrine
 receptor
 receptor
 receptor
Glycogen deposits
Figure 45.9 One hormone, different effects.
Vessel dilates.
Vessel constricts.
Glycogen breaks down and glucose is released from cell.
(a) Liver cell
(b)
Skeletal muscle blood vessel
Intestinal blood vessel
(c)

7. S cells of duodenum secrete the hormone secretin ( ).
Figure 45.11
Pathway
Example 
Stimulus
Low pH in duodenum
S cells of duodenum secrete the hormone secretin ( ).
Endocrine cell
Hormone
Negative feedback
Figure A simple endocrine pathway.
Blood vessel
Target cells
Pancreas
Response
Bicarbonate release

8. Hypothalamus/ posterior pituitary
Figure 45.12
Pathway
Example 
Stimulus
Suckling
Sensory neuron
Hypothalamus/ posterior pituitary
Posterior pituitary secretes the neurohormone oxytocin ( ).
Neurosecretory cell
Positive feedback
Neurohormone
Blood vessel
Figure A simple neuroendocrine pathway.
Target cells
Smooth muscle in breasts
Response
Milk release

9. Liver, bones, other tissues
Figure 45.16
Tropic effects only: FSH LH TSH ACTH
Neurosecretory cells of the hypothalamus
Nontropic effects only: Prolactin MSH
Nontropic and tropic effects: GH
Hypothalamic releasing and inhibiting hormones
Portal vessels
Endocrine cells of the anterior pituitary
Posterior pituitary
Pituitary hormones
Figure Production and release of anterior pituitary hormones.
HORMONE
FSH and LH
TSH
ACTH
Prolactin
MSH GH
TARGET
Testes or ovaries
Thyroid
Adrenal cortex
Mammary glands
Melanocytes
Liver, bones, other tissues

10. Figure 45.UN04
Figure 45.UN04 Appendix A: answer to Test Your Understanding, question 9