16.1 The endocrine system is one of the body's two major control systems

Neuroendocrines

Along with neural functions, they also produce and release hormones; nervous system and endocrine effects

Hormones

Chemical messengers secreted by cells into the extracellular fluid

LONG

Duration of endocrine system responses:

SHORT

Duration of nervous system responses:

Diffuse locations where targets can be anywhere blood reaches

Endocrine system acts at what type of location?

SLOW responses

Endocrine system initiates:

Scattered apart

Endocrine systems are not grouped together but are...

Example of neuroendocrines

Epinephrine and dopamine

Certain prostaglandins released by smooth muscle cells cause those smooth muscle cells to contract

Example of autocrines

Tissues with endocrine functions

Gonads, pancreas, and placenta

They are arranged in cords and branching networks, which maximizes contact between them and the surrounding capillaries

How are most of the hormone reducing cells in endocrine cells arranged?

By means of hormones

How does the endocrine system influence metabolic activity?

Long distances

In the endocrine system hormones act over?

Short distances

In the nervous system neurotransmitters act over?

Hormones

Long distance chemical signals that travel in blood or lymph throughout the body

Specific locations determined by axon pathways

Nervous system acts at what type of location?

RAPID responses

Nervous system initiates:

Endocrine glands

Produce hormones and lack ducts; release hormones into the surrounding tissue fluid and typically have rich vascular and lymphatic drainage that receives their hormones; travel through the blood to a distant organ

Autocrines

Short distance chemical signals that exert their effects on the same cells that secrete them

Example of paracrines

Somatostatin released by one population of pancreatic cells inhibits the release of insulin by a different population of pancreatic cells

pituitary, thyroid, parathyroid, adrenal, and pineal glands

The endocrine glands include?

Hormones released into the blood

The endocrine system acts via:

Neuroendocrine organ

The hypothalamus, along with its neural functions, produces and releases hormones

Action potentials and neurotransmitters

The nervous system acts via:

Reproduction, growth and development, maintenance of electrolytes, mobilization of body defenses, and regulation of cellular metabolism and energy balance

What are the major processes that hormones control and integrate?

Responses that typically occur after a lag period of seconds of even days

What does binding of a hormone to cellular receptors initiate?

They only contain endocrine tissue and do not function as a gland itself.

Why are the gonads, pancreas and placenta not considered an endocrine gland?

Exocrine glands

produce nonhormonal substances, such as sweat and saliva, and have ducts that carry these substances to a membrane surface

Paracrines

short-distance chemical signals that act locally (within the same tissue) but affect cell types other than those releasing the paracrine chemicals

Endocrinology

the scientific study of hormones and endocrine organs