BIOL 005B Lecture Notes - Lecture 12: Endocrine System, Autocrine Signalling, Prostaglandin
BIOL 005B Lecture 12: Control Systems: Hormones
●Overarching Control in Organisms
○Two systems coordinate communication throughout the body: the endocrine
system and the nervous system
○The endocrine system secretes hormones that coordinate slower but longer-acting
responses including reproduction, development, energy metabolism, growth, and
behavior
○The nervous system conveys high-speed electrical signals along specialized cells
called neurons; these signals regulate other cells
●Hormones: The Body’s Long-Distance (but slower) Regulators
○Animal hormones are substances produced in one body region that have effects in
some other region; they are chemical messengers
○Animals hormones are chemical signals that are usually secreted into the
circulatory system and communicate regulatory messages within the body
○Hormones tend to reach all parts of the body, but only target cells are equipped to
respond
○Hormones mediate responses to environmental stimuli and regulate growth,
development, and reproduction
●Hormones and other signaling molecules bind to target receptors, triggering specific
response pathways
○Examples of SIGNALING CHEMICALS, hormones are just one type:
■Endocrine hormones: produced in specialized endocrine (‘ductless’)
glands and distributed in blood
■“Local regulators of messengers”: not produced on specialized glands;
tend to have local effects on nearby cells via diffusion (histamine,
prostaglandins, nitrous oxide, cytokines, etc)
●Paracrine signals act on cells near the secreting cell
●Autocrine signals act on the secreting cell itself
■Neurotransmitters and neurohormones: released from nerve cells directly
onto other cells or into blood
●At synapses, neurons often secrete chemical signals called
neurotransmitters that diffuse a short distance to bind to receptors
on the target cell
○Play a role in sensation, memory, cognition, and movement
●Neurohormones originate from neurons in the brain and diffuse
through the bloodstream
■Pheromones mediate interactions between individuals
●They are produced by one individual and change the behavior or
physiology of other individuals
●Pheromones are extremely common in all sorts of animals:
○Species recognition
○Group recognition
○Territory marking
○Navigation, trail marking
Document Summary
Two systems coordinate communication throughout the body: the endocrine system and the nervous system. The endocrine system secretes hormones that coordinate slower but longer-acting responses including reproduction, development, energy metabolism, growth, and behavior. The nervous system conveys high-speed electrical signals along specialized cells called neurons; these signals regulate other cells. Hormones: the body"s long-distance (but slower) regulators. Animal hormones are substances produced in one body region that have effects in some other region; they are chemical messengers. Animals hormones are chemical signals that are usually secreted into the circulatory system and communicate regulatory messages within the body. Hormones tend to reach all parts of the body, but only target cells are equipped to respond. Hormones mediate responses to environmental stimuli and regulate growth, Hormones and other signaling molecules bind to target receptors, triggering specific development, and reproduction response pathways. Examples of signaling chemicals, hormones are just one type: Endocrine hormones: produced in specialized endocrine ( ductless")
