Physiology of Endocrine System Lecture 1

What is Endocrine Physiology?

• The study of hormones and their actions.

• The study of how endocrine glands regulate the physiology and behavior of animals.

What does the exocrine gland release

releases products onto internal or external surfaces via a ductal system.

What are the key features of the exocrine glands

•Uses ducts (except unicellular exocrine glands like goblet cells)

•Secretes onto body surfaces or into lumens

•Local action (not systemic)

What are the key features of the endocrine glands

•No ducts

•Hormones enter blood or lymph

•Long-distance signaling (endocrine signaling)

What does the endocrine gland secrete and do

is a ductless gland that secretes hormones directly into the bloodstream or interstitial fluid, allowing those hormones to act on distant target cells through circulation.

What are mixed aka heterocrine glands

Some glands contain both endocrine and exocrine components within the same organ;

Whats an example of a heterocrine gland organ

the pancreas

Endocrine signaling is not restricted to

classical endocrine glands

many organs throughout the body secrete what

hormones or hormone-like factors that contribute to systemic regulation

What system works with the endocrine system

works closely with the nervous system

What is the significance in the nervous system in the eondcrine system

• Utilizes electrochemical signals and synaptic transmission

• Very rapid responses (<1 sec)

What is the significance of the eondcrine system

• Chemical messengers ( hormones) are transported in extracellular fluids.

• May act over extended periods (minutes to months)

How does the nervous system interact with the endocrine system?

• Endocrine tissues are innervated

• Some responses take the form of neuroendocrine reflexes

Endocrine cells of the adrenal medulla (chromaffin cells), are directly controlled

by

preganglionic sympathetic neurons

In response to stress, (chromaffin cells) these cells secrete

catecholamines, mainly epinephrine and norepinephrine, directly into the bloodstream for a rapid fight-or-flight response.

Another example of neuroendocrine integration is the

“milk-letdown” reflex

Some neurons produce what ?

hormones

Neurosecretory cells do not make whtat?

synaptic connections

So neurisecretatory do not make synaptic connections so what to they make

release neurohormones into the bloodstream

What kind of molecules are hormones

regulatory molecules

Where are the hormones (regulatory molecules) secreted

into the extracellular fluid/blood by endocrine secretory cells.

What does the hormones affect

They affect other tissues at Low Concentrations

Other types of control systems use what kind of communication

• chemical substances that are not transported in the vascular system to influence distant cell activity.

• These systems serve as a means of local integration among or