History

• Friedrick Henle

  • First to recognize ductless glands

• Claude Bernard

  • Discovered internal secretions

• Charles Brown-Sequard

  • First attempt at endocrine therapy

• Ernest Starling

  • Called these chemicals hormones

• Insulin

  • Discovered that diabetes was due to lack of insulin

  • On 1923, doctors were running around, injecting children with insulin and saving them

Nervous System vs. Endocrine System

• Endocrine system takes the information from the nervous system and taking that information to make the processes happen

Endocrine system

• Regulates and coordinates many different functions in your body through the secretion of hormones from different glands

• Endocrine glands secrete hormones into the bloodstream/extracellular fluid

Steroid hormones

• These are hormones that we are naturally producing all the time

• Steroid hormones bind to intracellular receptors and affect transcription

• Synthetic hormones were developed to improve lives

• Types

  • Androgens (testosterone and DHEA)

  • Estrogens

  • Glucocorticoids

    • Inflammation reducer

    • Used to treat autoimmune diseases and multiple sclerosis

  • Mineralocorticoid

    • Used for treating adrenal insufficiencies

    • Help maintain electrolyte balance

• Amino Acid Hormones

  • Prolactin

    • Breast milk stimulation

    • Bonding

  • Insulin

  • Parathyroid

    • Balance calcium in blood

  • Epinephrine

    • Adrenaline

    • Fight or flight response

    • Anaphylaxis

      • Intense and acute allergic reactions (Epipen)

    • Melatonin

      • Mimics tryptophan

        • In turkey (why people get tired from Thanksgiving dinners)

      • Makes people sleep

    • ACTH (adrenocorticotropic hormone)

      • Regulates stress, metabolism, and external functions

      • Stimulates adrenal glands to release cortisol

Feedback loops

• Positive

  • Causes the body to go further away from equilibrium/homeostasis

  • Example

    • Baby giving birth

      • Pushes against the cervix

      • Stretching of cervix causes nerve impulses to be sent to the brain

      • Brain stimulates posterior pituitary gland to release oxytocin

      • Oxytocin causes smooth lining of the uterus to contract

• Negative

  • Causes the body to move back toward homeostasis

  • Example

    • Cold

      • Shivering (body mechanism to cause heat)

      • Body temperature increases

    • Heat

      • Sweating (cooling mechanism)

      • Body temperature decreases

Glands

• Hypothalamus

  • Coordinate nervous and endocrine systems

  • Sends signals to the pituitary gland

  • Controls

    • Body temperature

    • hunger/thirst

    • Mood

    • Sex drive

    • sleep 

    • Blood pressure

• Pituitary gland

  • Known as the master gland

  • The pituitary gland controls other glands

  • Secretes

    • Growth hormones - muscles, bones

    • Oxytocin - maternal bonding, breast and uterine tissue, sperm motility, testosterone levels, aggression towards the out group

    • Prolactin - stimulates breast milk production

  • Pituitary lobes

    • Anterior lobe

      • 80% total weight and made of epithelial cells

      • Secretes

        • ACTH

        • FSH

          • Stimulates sperm and egg production

        • Growth hormone

        • LH

          • Regulates ovary and testicle function, production, and mobility

        • Prolactin

        • TSH (thyroid)

          • Stimulates thyroid to regulate metabolism

    • Posterior lobe

      • Smaller lobe

      • Secretes

        • Oxytocin

        • Vasopressin

          • Regulates sodium balance in the body

• Pineal gland

  • Helps regulate your circadian rhythm

    • Produces melatonin

    • Affected by light on retina

    • Don’t be on electronics before sleeping because that sets your melatonin production back to 20-30 minutes

• Thyroid gland

  • Situated in the neck and influences metabolism and growth

  • Releases thyroxine, which regulates

    • Metabolism regulation

    • Mood

    • Body temperature

    • Digestive functions

    • Bone health

  • Symptoms of malfunction

    • Sleepy

    • Gaining weight

    • Mood swings

  • Disorders

    • Hyperthyroidism

      • Producing too much thyroxine

      • Losing weight

      • Heat intolerance

      • Nail thickening

      • Nervousness and anxiety

      • Muscle weakness

      • Diarrhea

      • Short and light periods

      • Increased sweating

    • Hypothyroidism

      • Not having enough thyroid function

      • Decreased sweating

      • Gaining weight

      • Cold intolerance

      • Slow heart rate

      • Puffy face

      • Constipation

      • Brittle nails

      • Depression and irritability

• Parathyroid gland

  • Four glands

  • Inside the thyroid

  • Regulate calcium hormone levels

• Adrenal glands

  • Sit on top of your kidneys like little tiny hats

  • Adrenal cortex

    • Deals with long-term stress

    • Secretes corticosteroids

    • Increases glucose production and kidney salt retention, increases blood pressure

  • Adrenal medulla

    • Short term stress

      • Fight or flight

Secretes epinephrine and norepinephrine

Diverts energy to the muscles

Talk to people to relieve stress

• Hugging people helps as well

Cortisol

• Released regularly throughout the day, peaking early but lower at night

• Stress causes your body to release higher than usual levels

  • Attempts to deal with stress, reduce inflammation increase blood glucose, etc

  • Consistent high levels can lead to negative physical consequences

Pancreas

• Glucagon

  • Alpha cells secrete this

  • Causes glycogen breakdown

  • Raises blood sugar

• Insulin

  • Beta cells secrete this

  • Store glucose as glycogen

  • Decrease blood sugar

• Diabetes

  • A healthy pancreas will produce the right amount of insulin for incoming glucose

  • Receptors open the gates and allow for incoming glucose

  • Type 1

    • There is no insulin released

    • Prevents cells from being able to access glucose

  • Type 2

    • The receptors no longer respond to insulin

    • Leads to too much glucose in the bloodstream

Gonad glands

• Testes

  • Mainly testosterone

    • Before birth, causes development of male sex characteristics

      • Lack = female

    • In adolescence, muscle and bone growth, and further development of sex characteristics

• Ovaries

  • Mainly estrogen and progesterone

  • Estrogen

    • Female secondary sex characteristics

    • Regulates menstruation, libido, emotions/mood, and memory

  • Progesterone

    • Works with estrogen to regulate the same things

    • Also does uterus preparation and maintenance

Vagus nerve - puts you body in a rest and digest state