1. The Endocrine System
Honors
Physiology

4. What are hormones? Hormones: send messages
act locally or at a distance
work quickly or slowly
can be created/excreted by cells, tissues or organs, collectively known as “glands”
secreted via epithelial cells  extracellular fluid  blood stream  receptors on target cells
ducts are not used by endocrine system

5. Comparison to Nervous System
Fig. 13.2

6. Comparison to Nervous System
Entity
Nervous Sys
Endocrine Sys
Cell type
Neurons
Epithelial
Chemical signal
Neurotransmitter
Hormone
Specificity of response
Receptors on postsynaptic cell
Receptors on target cells
Speed
Milliseconds
Seconds to hours
Length of effect
Brief
Brief or long

7. Example of Hormonal Regulation—Today’s Lab
Thyroxine
Released from thyroid gland
Target: cells all over body
Influences metabolism
Thyroid stimulating hormone (TSH)
Released from anterior pituitary gland
Target: thyroid gland
Signal: “release thyroid hormones!”

8. Endocrine System—Relative Stability of Hormone Concentrations
Negative feedback maintains stable hormone levels
Fig

9. Endocrine System—3 Ways To Control Hormonal Secretions
Fig. 13.8

10. Example: Negative Feedback Controls Blood Glucose Levels
What happens when your blood glucose gets too low?
Fig 13.36

11. Example: Negative Feedback Controls Blood Glucose Levels
What happens when your blood glucose gets too high?
Fig 13.36

12. Steroid Hormones
Fig. 13.5

13. Steroid Hormones Lipid soluble Receptor in the nucleus
binds hormone  gene transcription
mRNA is then translated into a protein in the cytoplasm
Examples
estrogen, testosterone
aldosterone, cortisol

14. Nonsteroid Hormones
Fig. 13.7

15. Nonsteriod Hormones Cannot move through lipid bilayer
Instead they bind to receptors in cell membrane
Examples:
TSH
Epinephrine
Glucagon

16. Hypothalamus
Regulates other glands to tell them when to release their hormones
Fig. 13.9

17. Pituitary Gland
Fig. 13.9

18. Anterior Pituitary Adrenocorticotropic hormone (ACTH) Gonadotropins
Target: adrenal cortex, stimulates cortisol release
influences protein and fat metabolism
Gonadotropins
follicle stimulating hormone (FSH)
egg or sperm maturation
For egg, stimulates release of egg from follicle mid cycle
luteinizing hormone (LH)
Stimulates release of sex hormones

19. Anterior Pituitary cont.
Growth Hormone (GH)
bone growth/osteogenesis
Melanocyte Stimulating Hormone (MSH)
skin color, includes tanning
Prolactin (PRL)
lactation
Thyroid Stimulating Hormone (TSH)
stimulates thyroid secretions

20. Robert P. Wadlow 8’ 11” Age Height 8 6’ 14 7’5” 18 8’4” 22 8’11”
Yikes, his anterior pituitary released too much growth hormone!
Age
Height 8 6’ 14
7’5” 18
8’4” 22
8’11”

21. Anterior Pituitary cont.
How am I going to remember all of this???
A Green Giant Makes PRetty Things
ACTH
Gonadotropins (FSH, LH/ICSH) GH
MSH PR
TSH

22. Posterior Pituitary Antidiuretic Hormone (ADH) Oxytocin
decreases urine formation
when you are dehydrated, your body says “don’t lose water!”, so ADH is increased
increased ADH = concentrated urine
Oxytocin
smooth muscle contractions in the uterus during childbirth
Recent studies = “bonding” hormone

23. Posterior Pituitary cont.
Why do you urinate more when you drink caffeine?
Your body recognizes caffeine as a toxin that it needs to expel from the body
Caffeine is a diuretic – it makes you urinate
it inhibits secretion of ADH
you don’t get the “don’t lose water!” signal
so you expel more water to try and flush out the toxin

24. Pineal Gland Melatonin
Helps regulate circadian rhythms (sleep-wake cycle)

25. Thyroid Thyroxine or tetraiodothyronine (T4)-and Triiodothyronine (T3)
regulate your food metabolism (break down glucose, fat & protein to create energy)
increase temperature, growth and development

26. Fig

27. Thyroid & Parathyroid Thyroid releases Calcitonin
lowers calcium levels in the blood
Parathyroid releases Parathyroid Hormone (PTH)
increases calcium levels in the blood
Fig

28. Pancreas Insulin Glucagon Islets of Langerhans
Fig
Insulin
Glucagon
Islets of Langerhans
regulate blood glucose levels
Both hormones created in the…
Amylase(carb), lipase(fat), trypsin & chymotrypsin(protein)

29. Pancreas cont. Islets of Langerhans
Alpha Cells
Make Glucagon
Released when your blood sugar levels get low
Increases blood glucose levels by breaking down glycogen (storage form of glucose in the liver) and noncarbohydrates into glucose
Beta Cells
Make Insulin
Released when your blood sugar levels get high
Tells your body cells to take sugar in, and decreases blood glucose levels by stimulating the liver to form glycogen

30. Pancreas cont. Diabetes- can’t regulate your blood glucose
Type I - Juvenile
Islets of Langerhans don’t work properly & cannot create sufficient insulin (or glucagon)
usually need insulin injections (why not glucagon injections?)
usually inherited
Type II - Adult onset
Insulin receptors throughout body don’t work properly
usually can use oral treatment
related to weight gain
About 17 million people in the US have diabetes!

31. Adrenal Glands Adrenal Medulla epinephrine/adrenalin
norepinephrine/noradrenalin
Increases blood glucose, heart rate, etc.
Blood vessels constrict in digestive tract and kidneys, dilate in blood vessels of the muscles
Fig
sympathetic division of the autonomic nervous system

32. Adrenal Glands cont. Adrenal Cortex Aldosterone
Target cells in kidneys
Maintain Na+ and K+ balance
Cortisol
Glucose, protein and fat metabolism
Anti inflammatory
Androgens
supplement gonad sex hormones

33. Reproductive Organs Ovaries Testes Estrogen Progesterone Testosterone
stimulates egg maturation
secondary female sex characteristics
Progesterone
maintains uterine lining in case of implantation
Testes
Testosterone
regulates spermatogenesis
secondary male sex characteristics

35. Adrenal Glands cont. Addison disease Cushing syndrome
Cortisol hyposecretion
low Na+, high K +, dehydration, low glucose, can be very serious
Cushing syndrome
Cortisol hypersecretion (usually
by too much ACTH)
High Na+, low K+, high glucose,
water retention

36. Thyroid cont. Grave’s disease Hashimoto’s disease too much hormone
Hyperthyroidism
Hashimoto’s disease
too little hormone
Hypothyroidism