Endocrine System By: Alexis Vallieu and Kayla Nollan

Functions of SystemThe Endocrine system is a system of glands, cells, tissues and organs that secrete hormones to sustain homeostatic levels.

Target CellsWhen hormones diffuse from interstitial fluid then eventually act on target cells within the bloodstream.

Secretion TypesThere are two different types of secretions.

These include paracrine, which effects only neighboring cells, and autocrine, which affects the secreting cell itself.

General Characteristics

Hormone Action

Steroid HormonesSteroid Hormones consists of complex rings of carbon and hydrogen atoms. They are insoluble in water and are carried in the bloodstream weakly bound to plasma proteins in a way that allows them to be released in decent sized quantities within the same area as their target cells.

Nonsteroid Hormone Nonsteroid hormones include amines, peptides, and proteins that usually bind to receptors in target cell membranes. Each receptor molecule is a protein that consists of a binding site and activity site.

Control of the Endocrine System

A: Hypothalamus and anterior pituitary stimulate other endocrine glands B: Nervous system stimulates the gland directlyC: changes in the internal environment stimulate glands directly.

Pituitary Gland It is attached to the hypothalamus and lies in the sella turcica of the sphenoid bone.

Inside the Pituitary Gland

Flow of HormonesHormones are stimulated in the anterior pituitary gland which then is released into the bloodstream and either goes to the target cells or thyroid gland. From there, thyroid hormones go back into the bloodstream and then go to the target cells.

Anatomy of the ThyroidThyroid glands consist of two lobes that connect in the back of the isthmus. Follicular cells secrete thyroid hormones, and calcitonin is secreted from extra follicular glands.

Gland Structure

Cortisol Secretion

Pancreas

Feedback Mechanism

Stress Response The stress response consist of the fight or flight response and the long term adjustment response.

Nervous Vs. Endocrine

Hormone Types

Thyroid Hormones

Epinephrine vs. Norepinephrine

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