Endocrine System Flashcards
What are prostaglandins made from?
The fatty acid arachidonate
Functions of prostaglandins
o Uterus – muscular contraction (period pains)
o Mediate effects of pyrogens (cause fevers)
o Memory & brain function.
o Increase blood flow in kidneys.
o Dilate small blood vessels – redness seen in inflammation.
o Protect stomach lining.
o Sensitise nerve endings that stimulate pain responses.
o Relax and contract lungs.
What are some growth factors produced in the body?
granulocyte & macrophage colony stimulating factor, platelet derived growth factor, epidermal growth factor, nerve growth factor.
What is leptin?
produced from adipose tissue – acts on hypothalamus to indicate satiety – obesity – genetic alteration of leptin – hypothalamic cells lack receptors.
What hormone is produced by the heart?
atrial natriuretic hormone – antagonistic of aldosterone
Describe the pineal gland?
brain – melatonin (regulates wake/sleep cycle)
Describe the thymus?
lobular & lies beneath sternum – converts lymphocytes into T lymphocytes – cells produce thymosin (aid in lymphocyte differentiation)
Describe the pancreas?
exocrine (digestive enzymes) & endocrine gland (insulin & glucagon - antagonistic)
What are the 2 parts of the adrenal glands?
adrenal medulla & adrenal cortex
Describe the adrenal glands?
sits above kidneys – hypothalamus controls.
Describe the adrenal medulla?
cells derived from peripheral nervous system – sympathetic division of the autonomic nervous system controls involuntary response & adrenal medulla – tropic hormones don’t trigger these cells – produces adrenaline (epinephrine) – heart rate quickens, increased chemical reactions, glucose released from liver.
Describe the adrenal cortex?
produces mineralocorticoids (regulate certain ions e.g. aldosterone), glucocorticoids (affect glucose metabolism – glucose broken down from non-carbohydrate substance), androgens (testosterone), progesterone, oestrogen
Describe the parathyroid gland?
parathyroid hormone (works with calcitonin) maintains optimum Ca levels – stimulates osteoclasts, kidneys to reabsorb Ca, intestinal cells to absorb Ca from food – antagonistic to CT
Describe the thyroid gland?
secretes T3 (triiodothyronine) & T4 (thyroxine) –controls metabolism – most body cells have receptors for thyroid hormones – cause effects of body – hyperthyroidism and hypothyroidism – calcitonin (decrease calcium levels)
What hormones are produced by the posterior pituitary?
Antidiuretic hormone & oxytocin
What is anti diuretic hormone?
control volume of blood – regulates water reabsorption in nephrons.
What is oxytocin?
females during pregnancy – binds to target cells in uterus - causes contractions
What hormones are described the anterior pituitary?
melanocyte stimulating hormone, prolactin, growth hormone, thyroid stimulating hormone, adrenocorticotropic hormone, gonadotropins (luteinising hormone and follicle stimulating hormone)
What is prolactin?
acts with oestrogen & progesterone to stimulate the mammary gland (produce breast milk)
What is melanocyte stimulating hormone?
acts on melanocytes – synthesise melanin pigment – epidermal cells in skin contain this pigment – genetically determine skin colour – UV stimulates MSH production, causes more melanin to be produced – protects against UV.
What is growth hormone?
increase rate of growth of skeleton – simulate cartilage & bone cells to reproduce and lay down intercellular matrix
What is thyroid stimulating hormone?
trigger T3 & T4 production (control growth, development & metabolism)
What is adrenocorticotropic hormone?
triggers adrenal cortex to produce steroid hormones – cortisol (regulates glucose production from fats & proteins) & aldosterone ( regulate sodium & potassium ions) – hormones involved in male secondary sexual characteristics
What is luteinising hormone?
male – stimulate testosterone production
females – stimulate release of egg, stimulates progesterone production
What is follicle stimulating hormone?
females – maturation of an egg evry month, stimulates secretion of oestrogen
males- triggers sperm production
What are the gonads?
Sex glands - testes & ovaries
What regulates the actions of the pituitary?
Hypothalamus
In what way does the hypothalamus regulate the posterior pituitary?
Via nerve impulses
In what way does the hypothalamus regulate the anterior pituitary?
By releasing hormones – travel via blood vessels.
How many hormones does the pituitary produce?
9
7 from anterior - 5 stimulatory, 2 inhibitory
2 from posterior
What is the hypothalamus?
mass of nerve cells – floor of brain connected to pituitary by stalk.
Explain feedback loops
o Endocrine glands stimulated to synthesised & secrete hormones.
Direct – nervous
Indirect – nervous system releases hormones
Conc. of substance in blood
o Hormone travels to target tissue via blood.
o Desired effect occurs.
o Feedback to endocrine gland - + more of hormone produced, - less hormone produced.
Give an example of antagonistic hormones
insulin & glucagon
o High sugar – insulin released by pancreas, cellular uptake of glucose, glycogen forms.
o Low blood sugar – glucagon released by pancreas, glycogen broken down.
What are the two type of hormones?
steroids & peptides
What are hormones?
chemical messengers – produced at one site travels via blood stream to another site where it has an effect.
What is a gland?
aggregation of cells specialized to secrete materials not related to their ordinary metabolic needs.
What is an endocrine gland?
ductless – secreted into bloodstream.
What is an exocrine gland?
secretes via ducts
Function of endocrine system?
helps maintain homeostasis, responds to stress stimuli (with nervous system), regulate growth & development
What is a neurosecretory cell?
specialised nerve cells – endocrine and neuron functions – conducts nerve impulses and secrete hormones
What system works with the endocrine system to coordinate physiological processes?
nervous system
What is the difference between a nerve response & hormonal response?
Nerve cell exerts control in its immediate vicinity by releasing neurotransmitters at synapses affecting nerve cells, muscle cells, or glands.
Endocrine gland exerts widespread control by releasing hormones into bloodstream.
What are the 4 functions of hormones?
regulation (control internal environment), response (change in external environment), reproductive, growth & development.
How do hormones produced a desired effect?
Hormones bind to receptor molecules embedded in membrane and located in cytoplasm – activates a chain of events – effect of the hormone is expressed.
What are steroid hormones synthesised from?
cholesterol
Which type of hormone can enter the cell?
steroid hormones
Describe steroid hormones
Synthesised from cholesterol – pass through cell membrane – bind to nuclear/cytosolic steroid hormone receptors – change in cell.
Describe peptide hormones
can’t enter cell, bind to receptors on outside and cause intracellular events or enzyme cascades.
Name the 3 type of recpetors for peptide hormones
- Single polypeptide chain with a domain on either side of the membrane, connected by a membrane-spanning domain e.g. epidermal growth factor
- Single polypeptide chain that is passed back and forth in serpentine fashion across the membrane, - intracellular, transmembrane & extracellular domains e.g. beta-adrenergic (adrenaline) receptor
- Multiple polypeptides e.g. insulin
