NEW Endocrine System Notes

Endocrine and Nervous

2 major regulatory systems of the body

Homeostasis

Endocrine & Nervous system are good for maintaining

Target Cells

Hormones (chemical messanagars) bind to

First step in Endocrine System Process

Secrete Hormone into Interstitial Fluid (space between cells) then diffuse into Blood Capillaries

Second step in Endocrine System Process

Blood transports hormones to heart via Veins

Third step in Endocrine System Process

After leaving heart, blood transports to body via Arteries

Fourth step in Endocrine System Process

In capillary beds, hormones diffuse out blood, into interstitial fluid, & bind to receptors on their target cells

Classic Endocrine Signals

Hormones secreted into blood to affect distant targets

Paracrine Signal

Cell thats going to secrete a chemical & going to influence a neighboring cell

Autocrine Signal

Unusual Signaling, chemical gets released into interstitial fluid (between cells) & comes back to stimulate the cell it released

Most common

How common are Endocrine Signals

More common

How common are Paracrine Signals

Less common

How common are Autocrine Signals

Endocrine Glands

Organs of Endocrine System (make the hormones & secrete them)

7 Primary Organs of Endocrine System

Anterior Pituitary Gland, Thyroid Gland, Parathyroid Gland, Adrenal Cortices, Endocrine Pancreas, Thymus, Ovaries or Testes

In Sphenoid bone in Skull

Location of Anterior Pituitary Gland

In Anterior Neck

Location of Thyroid Gland

On Posterior Thyroid

Location of Parathyroid Gland

On Superior Surface of Kidneys

Location of Adrenal Cortices

In the leftside of the Abdominopelvic Cavity mostly posterior to the stomach

Location of Endocrine Pancreas

On Superior Mediastinum

Location of Thymus

In Pelvic Cavity in females & suspended below pelvic cavity in males

Location of Ovaries or Testes

Secondary Endocrine Glands

Organs that produce hormones, but belong to other systems (Includes Testes, Ovaries, Heart, Kidneys, Small Intestine, & Adipose Tissue)

Neuroendocrine Organs

Nerve tissue that secretes chemicals that act like hormones, called Neurohormones (Includes Hypothalamus, Pineal Gland, Adrenal Medulla)

Paraneoplastic Syndrome

Cancer cells that produce hormones

Lungs & GI Tract

Most common place for Paraneoplastic Syndrome is

Imbalancing fluids, ion concentration, & ability to maintain homeostasis

Paraneoplastic Syndrome can cause issues with

Amino Acid-Based Hormones (building blocks for protein)

Produced in Hypothalamus, Adrenal Medullae, & Thyroid Gland

Hydrophobic

Is the Thyroid Gland Hydrophilic or Hydrophobic?

Peptide (Protein) Hormone

• Consists of several to hundreds of amino acids linked by Peptide Bonds

• Produced in Hypothalamus, Pancreas, Anterior Pituitary, Thyroid, & Parathyroid Gland

• Hydrophilic

Steroid Hormone

• Derived from Cholesterol

• Produced In Adrenal Cortices, Testes, & Ovaries

• Hydrophobic, AKA Lipid-Soluble because they can mix with fats & be stored in Adipose Tissue

Free Hormones

Small Amino Acid or peptide based that travel freely in blood (HAVE to be hydrophilic)

Bound Hormones

Form complex with binding protein (mostly Hydrophobic)

Target Cells

Cells that have Receptors that a hormone can bind to

3-dimensional; Low concentration

Receptors have _______ shape & can bind at ___ _________________

Opposite Effects

Binding to different receptors may produce

Hydrophilic & Hydrophobic Hormones

Hormone receptors in plasma membrane bind

Hydrophobic Hormones

Hormone receptors in Cytosol or Nucleus bind only