Endocrine Systems

Endocrine - ductless glands

Types of glands :

Endocrine glands- secrete their hormones directly into the bloodstream

• Secreting cell ones to the target cell

Exocrine glands - send chemical substances ( tears, sweat, milk, saliva) via ducts to the outside of the body

Endocrine Disorders

Hypo secretion and hyper secretion of hormones result in several well described disorders

Endocrine System

• A chemical communication system that controls many body functions

  • glands that produce the hormones to regulate the body’s activities

  • Controller in your body

  • Works w/ nervous system to regulate

  • Sends messages using chemicals

  • Several glands located throughout your body

Homeostasis

• when the endocrine system helps maintain a constant internal environment in the body

  • negative feedback loop - reverses direction of change

  • Positive feedback loop - amplifies change

Prostaglandins

• Usually produced in tissue and only go a short distance

• Often called tissue hormones or paracrine glands Types

• Made at sites of tissue damage or infection

  • causes pain or fever

  • Healing process

• Thromboxane - creates blood clot to try to heal

Pituitary Gland

• connected to the anterior and posterior pituitary lobe

  • Anterior lobe is controlled by the hypothalamus hormones

    • hypothalamic releasing and hypothalamic inhibitory hormones

      1. GnRh (gonadotropin releasing hormone) = FSH/LH (follicle stimulating hormone and Luteinizing hormone) target organ is gonads (male - testes / female - ovaries)

      2. CRH (corticotropin releasing hormone) = ACTH (adrenocorticotropic hormone) target organ is adrenal cortex

      3. TRH (Thy-rotropin releasing hormone) = TSH (thyroid- stimulating hormone) target organ is Thyroid

      4. PHR + (Prolactin inhibiting hormone) / Dopsmine - = PRL (Prolactin) . Target organ is mammary gland (milk making hormone)

      5. GHRH + (growth releasing hormone) / Somatostatin - = GH (growth hormone) target organ liver and all body

  • Posterior lobe is controlled by the hypothalamus nerve signals

    • hypothalamus makes and releases hormones of the posterior pituitary

    • posterior lobe stores tow hormones - ADH and oxytocin

    • Releases hormones when neurally stimulated by hypothalamus

      1. ADH - antidiuretic hormone

         • also known as vasopressin

      • target organ - kidneys

      • Retains urine and reduces output

      • Regulates blood pressure

      • Anti diabetic hormone

        2. Oxytocin

      • Contractions

      • Produces milk

      • Emotional bonding hormone

      • A love hormone

• Protected by the sphenoid bone And in between the sella turcica

• Hypothalamus significantly influences the pituitary gland

Hypothalamic- Pituitary - Thyroid Axis

Thyroid Hormones

• thyroid is located in throat

• Functions

  • helps in regulating metabolic rate

  • Controls the heart rate

  • Helps lower body temp

  • Helps digest

  • Affects immune system

• Thyroid Hormones

  1. Thyroxine (T4) 90%

  2. Triiodothyronine (T3) 10%

  3. Calcitonin

     • protects the bones, needs to be level amount if too low bones will be too week if too high bones will become to big

     • Parathyroid glands - releases PTH (parathyroid hormone) promotes osteoclasts (bone eating activity)

     • Calcitonin - deposits calcitonin on bones and increases bone strength

• Adrenal glands

  • above the kidneys

  • Two layers of adrenal glands : cortex and medulla

  • Adrenal Cortex (outer layer of the adrenal glands)

    • Zona glomerulosa = mineralcorticoids (aldosterone)

    • Zona Fasciculta = glucocorticoids (cortisol, corticosterone)

    • Zona reticularis = androgen (hydroepiandrosterone)

      • innermost layer of the adrenal cortex

      • Secretes androgen which play a early role in development of reproductive organs

        • in women they may stimulate sexual drive

  • Adrenal Medulla (inner part of adrenal glands above)

    • Adrenal medulla = catecholamines (epinephrine (ER) , norepinephrine (NR))

      • epinephrine is also known as adrenaline

      • Responds quickly to stress because of nerve impulse

      • Produce body’s fight or flight response

      • Increased BP

      • Increased blood supply

      • Increased heart rate

      • Increased glucose

  • Aldosterone

    • controls blood pressure and blood volume

    • Loves sodium and hates potassium

    • Retains sodium and water which raises the blood volume and blood pressure

• Stress response -

  1. Stress trigger - stress activates the brain

  2. The brain signals the pituitary gland which releases ACTH (adrenocorticotropic hormone)

  3. ACTH travels to adrenal gland making them release cortisol and adrenaline

     • cortisol breaks down muscle protein

     • Forms gyclcogen (glycogenesis)

       • too much cortisol will increase blood glucose

     • It is antiflammatory

     • Anti immunity

  4. The hormones will trigger some affects

     • increased blood pressure

     • Sweating

     • Increased breathing rate

     • Accelerated heart rate

     • Tunnel vision

     • Digestion slows down

• Alpha cells : secrete glucagon (raises blood sugar)

• Beta cells : secrete insulin (lowers blood sugar)

  • eating - blood sugar increases

  • Exercise - blood sugar decreases

• type 1 diabetes

  • young (less than 35)

  • Rapid symptoms

  • Not obese

  • Body doesn’t produce insulin

  • Managed by insulin injections, diet, and exercise control

• Type 2 diabetes

  • older

  • No symptoms early on

  • Obese

  • Insulin can be normal or abnormal, but body cells are resistant to insulin

  • Managed by oral medications, insulin injections, diet, and exercise

Thymus Gland

• triangular organ found in lungs

• Function

  • produces thymus in

  • Responsible for maturation of t-lymphocytes in childhood

  • Protects the body throughout life from pathogens (germs)

• ADH and Oxytocin are produced by cell bodies located in the hypothalamus but are released in pituitary gland making

Pineal Gland

• pine nut sized

• “The third eye”

• Secreting melatonin

  • reacts to dim light and causes sleep

  • Increased at nighttime and decreases during the day