Fundamentals of Biology - Lecture Outlines: Chapter 36 Endocrine System
Signaling Molecules
1. Neurotransmitters
2. Local signaling molecules
3. Pheromones
4. Hormones
Steroid Hormones
- lipid soluble
- derived from cholesterol
- adrenal glands + reproductive organs
- diffuse into nucleus
- bind to proteins
- switch genes on or off
Example: estrogen
Peptide Hormones
- receptor on target cell
- binds to peptide hormone
- stimulates production of cyclic AMP
- activates enzymes
Example: Glucagon
- receptors on liver cells
- reaction converts glycogen --> glucose
Neural-Endocrine Control
Hypothalamus
- deep in forebrain
- monitors internal conditions
- secretes
Pituitary Gland
- 2 lobes
Posterior Lobe
- nervous tissue
- cell bodies of neurons in
- ADH = antidiuretic hormone
- acts on kidney tubules
- promotes
- Oxytocin
- triggers uterine contractions
Anterior Lobe
- glandular tissue
- picks up hormones secreted by
- takes them to secondary capillary bed
- act on endocrine cells
- ACTH
- TSH
- FSH, LH
- PRL
- STH = growth hormone
Abnormal Pituitary Output
In childhood
- too much STH
- too little STH
In adulthood
- too much STH
Feedback Loops
Control of menstrual cycle
a. releasing hormone
b. FSH and LH
c. estrogen rises
d. LH surge
e. rising levels of progesterone and estrogen
Positive feedback triggers egg release
Negative feedback prevents release of another
Review
Review questions 1-5
Self quiz 1-4, 6-8