Hormones and the Endocrine System
Hormones and the Endocrine System
26.1 Chemical and electrical signals coordinate body functions
The Endocrine System is a group of interacting glands and tissues throughout the animal body that produce and secrete chemical to initiate and maintain body functions and activities.
Chemical Signals -Hormones - are released into the bloodstream by endocrine cells and carried to all locations in the body
Consists of all hormone secreting cells
Works with the nervous system in regulating body activities
Compared to the nervous system the response of the endocrine system is lower but is longer lasting
Well suited for coordinating gradual changes that affect the entire body
The Nervous System, the signals are primarily electrical and are transmitted via nerve cells called neurons.
Well adapted for directing immediate and rapid responses to the environment.
Ex. The flick of a frog’s tongue as it catches a fly results from high speed nerve signals
Hormones are made and secrete by organs called Endocrine Glands, a ductless gland that synthesizes hormone molecules and secretes them directly to the bloodstream
Ex. Endocrine glands in vertebrates are pituitary gland at the base of the brain, which regulates growth and reproduction, and the thyroid gland in the lower neck, which regulates metabolism.
The process of endocrine signaling
The membrane-enclosed secretory vesicles in an endocrine cell are full of hormone molecules.
The endocrine cell secretes the molecules directly into the blood vessels.
From there, the hormone can travel via the circulatory system to all parts of the body, but ONLY certain types of cells, called Target Cells, have receptors for that specific hormone.
Summary- 1). Stimulus 2). Signal travels everywhere via the bloodstream 3). Response: Limited to cells that have the receptor for the signal
Signaling in the Nervous System
Signal travels along the axon to a specific location
There is a direct connection (through specialized cell junctions)
26.1 Chemical and electrical signals coordinate body functions
The Endocrine System is a group of interacting glands and tissues throughout the animal body that produce and secrete chemical to initiate and maintain body functions and activities.
Chemical Signals -Hormones - are released into the bloodstream by endocrine cells and carried to all locations in the body
Consists of all hormone secreting cells
Works with the nervous system in regulating body activities
Compared to the nervous system the response of the endocrine system is lower but is longer lasting
Well suited for coordinating gradual changes that affect the entire body
The Nervous System, the signals are primarily electrical and are transmitted via nerve cells called neurons.
Well adapted for directing immediate and rapid responses to the environment.
Ex. The flick of a frog’s tongue as it catches a fly results from high speed nerve signals
Hormones are made and secrete by organs called Endocrine Glands, a ductless gland that synthesizes hormone molecules and secretes them directly to the bloodstream
Ex. Endocrine glands in vertebrates are pituitary gland at the base of the brain, which regulates growth and reproduction, and the thyroid gland in the lower neck, which regulates metabolism.
The process of endocrine signaling
The membrane-enclosed secretory vesicles in an endocrine cell are full of hormone molecules.
The endocrine cell secretes the molecules directly into the blood vessels.
From there, the hormone can travel via the circulatory system to all parts of the body, but ONLY certain types of cells, called Target Cells, have receptors for that specific hormone.
Summary- 1). Stimulus 2). Signal travels everywhere via the bloodstream 3). Response: Limited to cells that have the receptor for the signal
Signaling in the Nervous System
Signal travels along the axon to a specific location
There is a direct connection (through specialized cell junctions)