Human Development Lecture 4 – The endocrine system
Hormones are chemical messengers. They are produced by the endocrine system,
together with the nervous system they control and coordinate our body processes.
Mechanisms of intercellular communication
• Direct communication; direct transfer to other cell; trough gap junctions; by
ions, small solutes and lipid-soluble materials
• Paracrine communication; use of chemical signals to transfer information from
cell to cell within a single tissue; through extracellular fluid; by paracrine
Growth factors, testosterone
• Autocrine communication; chemicals affect the same cell that
secreted them; through extracellular fluid; by autocrine
Estrogen, interleukin-1
• Juxtacrine; intercellular communication through physical
contract between membrane components (oligosaccharides,
lipids, proteins)
Growth factors, cytokines and chemokines
• Endocrine communication; through the bloodstream; by hormones
o Non-neuronal endocrine cells; release in endocrine cell and then to
blood stream
o Neurosecretory cells; release in pituitary and then to
blood stream
• Synaptic communication; across synapses; by
neurotransmitters
Communication in our body;
By hormones and neurotransmitters;
Differences;
1. Distance sender-receiver
a. Neurotransmitter; nearby
b. Hormones; far away
2. Delay action-reaction
a. Neurotransmitter; fast reaction
b. Hormones; can be slow reaction
3. Specificity
a. Neurotransmitter; very specific
b. Hormones; not very specific
Similarities;
1. Both systems release chemicals that bind to specific receptors on target cells
2. Share many chemical messengers
3. Both systems are regulated by negative feedback control
4. They both preserve homeostasis by coordinating and regulation.
Neurotransmitters systems; Glutatmate, GABA, Ach, Serotonin (5-HT), glycin
Non-neuronal endocrine cells; Epinephrine (adrenaline), norepinephrine, cortisol →
by adrenal. Estrogen → by overies. Testosteron → by tesicles. Insulin → by
pancreas.
Neurosecretory cells; Oxytocin, vasopressin, FHS, LH, ACTH release
Hormones are chemical messengers. They are produced by the endocrine system,
together with the nervous system they control and coordinate our body processes.
Mechanisms of intercellular communication
• Direct communication; direct transfer to other cell; trough gap junctions; by
ions, small solutes and lipid-soluble materials
• Paracrine communication; use of chemical signals to transfer information from
cell to cell within a single tissue; through extracellular fluid; by paracrine
Growth factors, testosterone
• Autocrine communication; chemicals affect the same cell that
secreted them; through extracellular fluid; by autocrine
Estrogen, interleukin-1
• Juxtacrine; intercellular communication through physical
contract between membrane components (oligosaccharides,
lipids, proteins)
Growth factors, cytokines and chemokines
• Endocrine communication; through the bloodstream; by hormones
o Non-neuronal endocrine cells; release in endocrine cell and then to
blood stream
o Neurosecretory cells; release in pituitary and then to
blood stream
• Synaptic communication; across synapses; by
neurotransmitters
Communication in our body;
By hormones and neurotransmitters;
Differences;
1. Distance sender-receiver
a. Neurotransmitter; nearby
b. Hormones; far away
2. Delay action-reaction
a. Neurotransmitter; fast reaction
b. Hormones; can be slow reaction
3. Specificity
a. Neurotransmitter; very specific
b. Hormones; not very specific
Similarities;
1. Both systems release chemicals that bind to specific receptors on target cells
2. Share many chemical messengers
3. Both systems are regulated by negative feedback control
4. They both preserve homeostasis by coordinating and regulation.
Neurotransmitters systems; Glutatmate, GABA, Ach, Serotonin (5-HT), glycin
Non-neuronal endocrine cells; Epinephrine (adrenaline), norepinephrine, cortisol →
by adrenal. Estrogen → by overies. Testosteron → by tesicles. Insulin → by
pancreas.
Neurosecretory cells; Oxytocin, vasopressin, FHS, LH, ACTH release
