1. Endocrine System

2. (a) Endocrine signaling
Figure 45.2a
Blood vessel
Response
(a) Endocrine signaling
Response
(b) Paracrine signaling
Figure 45.2 Intercellular communication by secreted molecules.
Response
(c) Autocrine signaling

3. (d) Synaptic signaling
Figure 45.2b
Synapse
Neuron
Response
(d) Synaptic signaling
Neurosecretory cell
Figure 45.2 Intercellular communication by secreted molecules.
Blood vessel
Response
(e) Neuroendocrine signaling

4. Major endocrine glands:
Figure 45.4
Major endocrine glands:
Hypothalamus
Pineal gland
Pituitary gland
Organs containing endocrine cells:
Thyroid gland
Thymus
Parathyroid glands (behind thyroid)
Heart
Liver
Adrenal glands (atop kidneys)
Stomach
Pancreas
Kidneys
Small intestine
Figure 45.4 Major human endocrine glands.
Ovaries (female)
Testes (male)

5. Cerebrum Pineal gland Thalamus Hypothalamus Cerebellum Pituitary gland
Figure 45.14
Cerebrum
Pineal gland
Thalamus
Hypothalamus
Cerebellum
Pituitary gland
Spinal cord
Hypothalamus
Figure Endocrine glands in the human brain.
Posterior pituitary
Anterior pituitary

6. Water-soluble (hydrophilic) Lipid-soluble (hydrophobic)
Figure 45.5
Water-soluble (hydrophilic)
Lipid-soluble (hydrophobic)
Polypeptides
Steroids
0.8 nm
Insulin
Cortisol
Amines
Figure 45.5 Hormones differ in structure and solubility.
Epinephrine
Thyroxine

7. Water- soluble hormone Lipid- soluble hormone
Figure
SECRETORY CELL
Water- soluble hormone
Lipid- soluble hormone
VIA BLOOD
Transport protein
Signal receptor
TARGET CELL OR
Signal receptor
Figure 45.6 Receptor location varies with hormone type.
Cytoplasmic response
Gene regulation
Cytoplasmic response
Gene regulation
NUCLEUS
(a)
(b)

8. 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

9. Estradiol (estrogen) receptor
Figure
Hormone (estradiol)
EXTRACELLULAR FLUID
Estradiol (estrogen) receptor
Plasma membrane
Hormone-receptor complex
NUCLEUS
CYTOPLASM
Figure 45.8 Steroid hormone receptors directly regulate gene expression.
DNA
Vitellogenin
mRNA for vitellogenin

10. 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)

11. 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

12. 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

13. Cerebrum Pineal gland Thalamus Hypothalamus Cerebellum Pituitary gland
Figure 45.14
Cerebrum
Pineal gland
Thalamus
Hypothalamus
Cerebellum
Pituitary gland
Spinal cord
Hypothalamus
Figure Endocrine glands in the human brain.
Posterior pituitary
Anterior pituitary

14. 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

15. Mammary glands, uterine muscles
Figure 45.15
Hypothalamus
Neurosecretory cells of the hypothalamus
Neurohormone
Axons
Posterior pituitary
Anterior pituitary
Figure Production and release of posterior pituitary hormones.
HORMONE
ADH
Oxytocin
TARGET
Kidney tubules
Mammary glands, uterine muscles

19. Figure 45.17
Pathway
Example
Stimulus
Cold
Sensory neuron 
Hypothalamus
Hypothalamus secretes thyrotropin-releasing hormone (TRH ).
Neurosecretory cell
Releasing hormone
Blood vessel 
Anterior pituitary secretes thyroid-stimulating hormone (TSH, also known as thyrotropin ).
Anterior pituitary
Tropic hormone
Negative feedback
Thyroid gland secretes thyroid hormone (T3 and T4 ).
Figure A hormone cascade pathway.
Endocrine cell
Hormone
Target cells
Body tissues
Increased cellular metabolism
Response

20. Hypothyroidism Goiter

21. Hyperthyroidism

23. Increases Ca2 uptake in intestines Active vitamin D
Figure
Increases Ca2 uptake in intestines
Active vitamin D
Stimulates Ca2 uptake in kidneys
PTH
Parathyroid gland (behind thyroid)
Stimulates Ca2 release from bones
Figure The roles of parathyroid hormone (PTH) in regulating blood calcium levels in mammals.
STIMULUS: Falling blood Ca2 level
Blood Ca2 level rises.
Homeostasis: Blood Ca2 level (about 10 mg/100 mL)

24. Rickets

26. (a) Short-term stress response and the adrenal medulla
Figure 45.21a
(a) Short-term stress response and the adrenal medulla
Stress
Nerve signals
Spinal cord (cross section)
Hypo- thalamus
Nerve cell
Nerve cell
Adrenal medulla secretes epinephrine and norepinephrine.
Effects of epinephrine and norepinephrine:
Adrenal gland
Figure Stress and the adrenal gland.
Glycogen broken down to glucose; increased blood glucose
Kidney
Increased blood pressure
Increased breathing rate
Increased metabolic rate
Change in blood flow patterns, leading to increased alertness and decreased digestive, excretory, and reproductive system activity

27. (b) Long-term stress response and the adrenal cortex
Figure 45.21b
(b) Long-term stress response and the adrenal cortex
Stress
Hypothalamus
Releasing hormone
Anterior pituitary
Blood vessel
ACTH
Effects of mineralocorticoids:
Effects of glucocorticoids:
• Retention of sodium ions and water by kidneys
• Proteins and fats broken down and converted to glucose, leading to increased blood glucose
Adrenal gland
Figure Stress and the adrenal gland.
Adrenal cortex secretes mineralo- corticoids and glucocorticoids.
• Increased blood volume and blood pressure
• Partial suppression of immune system
Kidney

30. Body cells take up more glucose. Insulin
Figure 45.13
Body cells take up more glucose.
Insulin
Beta cells of pancreas release insulin into the blood.
Liver takes up glucose and stores it as glycogen.
STIMULUS: Blood glucose level rises (for instance, after eating a carbohydrate-rich meal).
Blood glucose level declines.
Homeostasis: Blood glucose level (70–110 mg/m100mL)
STIMULUS: Blood glucose level falls (for instance, after skipping a meal).
Figure Maintenance of glucose homeostasis by insulin and glucagon.
Blood glucose level rises.
Liver breaks down glycogen and releases glucose into the blood.
Alpha cells of pancreas release glucagon into the blood.
Glucagon