Ch. 8 Chemical Signals – Ch. 8 Chemical Signals – Maintaining Homeostasis Maintaining Homeostasis

The Endocrine SystemThe Endocrine System

HomeostasisHomeostasis

What is it ??What is it ??

Looked at Autonomic Nervous SystemLooked at Autonomic Nervous System

Discussed Sympathetic (stress) & Discussed Sympathetic (stress) & Parasympathetic (return)Parasympathetic (return)

These systems work in conjunction with These systems work in conjunction with the Endocrine System the Endocrine System

What is it ?What is it ?

The endocrine system is a collection of The endocrine system is a collection of glands that secrete chemical messages glands that secrete chemical messages we call hormoneswe call hormones

Hormone: A chemical substance secreted Hormone: A chemical substance secreted by a gland which provokes a response in by a gland which provokes a response in other cells.other cells.

PurposePurpose

1)1) Overall metabolismOverall metabolism2)2) Maintain homeostasisMaintain homeostasis3)3) GrowthGrowth4)4) ReproductionReproduction5)5) MoodMood

Main ComponentsMain Components

Hypothalamus Hypothalamus

Endocrine GlandEndocrine Gland

A tissue which releases (secretes) a A tissue which releases (secretes) a substance (hormone) into the blood substance (hormone) into the blood stream; this substance then travels via the stream; this substance then travels via the blood to influence target cellsblood to influence target cells

Therefore….Therefore….

The Endocrine System works together The Endocrine System works together with the Nervous System to provide with the Nervous System to provide control over the entire body. control over the entire body.

Note:Note:

1) NS 1) NS Adjusts quickly Adjusts quickly

2) ES 2) ES Adjusts over longer periods of Adjusts over longer periods of time. time.

How Much ??How Much ??

Only a small amount of a hormone is Only a small amount of a hormone is required to alter cell metabolismrequired to alter cell metabolism

HormonesHormones

Already stated that: Already stated that:

HormonesHormones are chemicals that are are chemicals that are secreted into secreted into the blood stream by the endocrine glandsthe blood stream by the endocrine glands

Hormones are received by target cells Hormones are received by target cells throughout the bodythroughout the body

Target cells have receptor proteins that help Target cells have receptor proteins that help determine the response to the hormonedetermine the response to the hormone

Different hormone/receptor combinations cause Different hormone/receptor combinations cause different responsesdifferent responses

In The Blood StreamIn The Blood Stream

Types of HormonesTypes of Hormones

Steroid HormonesSteroid Hormones

Lipid soluble…means ??Lipid soluble…means ??

Target Cell Creates ResponseTarget Cell Creates Response

StructureStructure

Steroid hormones are Steroid hormones are created by modifying created by modifying cholesterol moleculescholesterol molecules

Visualize…Visualize…

Steroid Hormone Video

Peptide and Amine Hormones Peptide and Amine Hormones

Peptide and Amine hormones are large Peptide and Amine hormones are large molecules that are not lipid soluble and molecules that are not lipid soluble and cannot enter target cells directly.cannot enter target cells directly. Also referred to as Protein HormonesAlso referred to as Protein Hormones

Visualize…..Visualize…..

Peptide HormonePeptide Hormone

Importance of cAMPImportance of cAMP

In Peptide and Amine hormones cyclic In Peptide and Amine hormones cyclic adenosine monophosphate (cAMP) acts adenosine monophosphate (cAMP) acts as a messenger.as a messenger.

cAMP activate enzymes which continue cAMP activate enzymes which continue the process.the process.

This pathway is known as the signal-This pathway is known as the signal-transduction-pathway. transduction-pathway.

Practice…Practice…

P. 377 Q. 1 - 4P. 377 Q. 1 - 4