Post on 17-Dec-2015
Endocrine system
Endocrine system• 3 types of regulatory molecules:
• 1) Hormones: regulatory chemicals secreted into blood by endocrine gland– Work only on ____________ cells (those that can
be influenced by its “message”)
Endocrine system• 3 types of regulatory molecules:• 2) Neurohormones: hormones released into blood
by some neurons
Endocrine system• 3 types of regulatory molecules:• 3) Paracrine hormones: chemicals secreted by
cells of organ that influence others in organ (not transported by blood)
Endocrine system3) Paracrine hormones. Example: prostaglandins. Derived
from cholesterol• Many functions: one is to promote inflammation (pain,
fever)• Aspirin, ibuprofen, celebrex: inhibit prostaglandin
production but vary in side effects (some can cause _____________ in small intestine, etc)
Endocrine system• Hormone chemistry:• 1) polypeptides: chains of amino acids (<100 aa’s
long). Ex, insulin, ADH (antidiuretic hormone)
Structure of insulin
Endocrine system• Hormone chemistry:• 2) glycoproteins: long polypeptide (>100 aa’s
long) with carbohydrate attached. Ex, FSH (follicle stimulating hormone) and luteinizing hormone (LH)
Endocrine system• Hormone chemistry:• 3) amines: variations of the amino acids tyrosine
and tryptophan. Ex, adrenalin, thyroxine.
tyrosine tyramine
adrenalinetryptophan
Endocrine system• Hormone chemistry:• 4) steroids: lipids derived from cholesterol. Ex,
testosterone, estradiol, progesterone
cholesterol
Endocrine system• Most hormones are hydrophilic (water soluble)• Recall from BIOL 1020 that cell membranes are
hydrophobic• This means that water-soluble molecules can’t
cross them.• How signal transmitted into cells? By __________
protein in membrane
Endocrine system• Hydrophilic hormone example• Hormone binding temporary, detaches and can
travel to another cell and bind again (and again)• 1 hormone molecule can signal many ________!
Endocrine system• Hydrophobic hormones are steroids and thyroxine• They penetrate membranes and bind to receptors
inside cell
Endocrine system• Example hydrophobic hormones are steroids
(testosterone, estradiol) and thyroxine
Endocrine glands• Pituitary gland: located under brain• Has two portions: anterior (in front) and posterior (in rear).
Each portion with different embryonic origin and very different functions
Endocrine glands• Posterior pituitary gland hormones
– Antidiuretic hormone (ADH): influences water reabsorption in kidneys.
– Note: alcohol consumption inhibits ADH secretion (so frequent need to _______________).
Endocrine glands• Posterior pituitary gland hormones
– Oxytocin: stimulates milk “let-down” in nursing mothers (milk secreted into ducts in breast). Also stimulates uterine contractions during childbirth.
Endocrine glands• Anterior pituitary gland hormones
– growth hormone (GH): stimulates growth of bone and muscle
– Too much: gigantism
8 feet 11 inches, 485 pounds.Lived 22 years, neverstopped growing!
Endocrine glands• Anterior pituitary gland hormones
– growth hormone (GH): stimulates growth of bone and muscle
– Too little: pituitary dwarfism
Endocrine glandsAnterior pituitary gland hormones
– follicle stimulating hormone (FSH) and luteinizing hormone (LH): involved in menstrual cycle in females and sperm production in males
Endocrine glandsAnterior pituitary gland hormones
– follicle stimulating hormone (FSH) and luteinizing hormone (LH): involved in menstrual cycle in females and sperm production in males
– prolactin (PRL): stimulates milk production in mammals
Endocrine glands• Thyroid gland: in throat just under larynx
Endocrine glands• Thyroid gland hormone (main):
– Thyroxine: helps set body’s metabolic rate– Too little: ______________. Often severe retardation.
Endocrine glands• Parathyroid glands: On thyroid
– Make parathyroid hormone (PTH): vital to maintain Ca+2 level in body
– Can influence Ca+2 reabsorption in kidney, Ca+2 release from bone, and absorption of Ca+2 in small intestine.
Endocrine glands• Adrenal glands: Located on kidneys
Endocrine glands• Adrenal glands
– Located on kidneys– Have cortex (outer) and medulla (inner) portions
Endocrine glands• Adrenal glands
– Medulla: secretes ______________ when stimulated by nerve system. Part of “fight or flight” response. Increase heart rate, blood pressure, blood glucose. Reduced blood flow to skin and digestive system
Endocrine glands• Adrenal glands
– Cortex: secretes corticosteroids. Involved in _________ balance, glucose balance, etc.
Endocrine glands• Pancreas
– Located below liver in abdomen
Endocrine glands• Pancreas
– Recall Islets of Langerhans. Make insulin and glucagon. Together, regulate glucose in blood.
Endocrine glands• Gonads (testes and ovaries)
Endocrine glands• Gonads (testes and ovaries)• Make steroid sex hormones• Testosterone, estradiol, progesterone (discussed)
Endocrine disruptors• Chemicals from environment that can interfere
with endocrine system• Chemical structures similar to those of some
hormones• Examples: pesticides, herbicides, etc.
Endocrine disruptors• Ex, Lake Apopka, Florida• 1980: chemical spill of pesticide DDT• Affected development of male alligators (lower
testosterone levels, smaller __________ size, anatomical defects)
Endocrine disruptors• Human concerns:• Puberty of females coming earlier• Many possible causes, but endocrine
disruptors may be involved
Endocrine disruptors• Ex, Michigan 1973• Chemical called PBB accidentally mixed into cattle food• Meat and dairy products reached 4,000 people• Daughters of women exposed surveyed in late 1990s• Menstruation started ______ years earlier in daughters of
exposed women