Exam #4: Endocrine System Flashcards
What are endocrine glands?
ductless glands that secrete hormones directly into the blood
What is the function of the pancreas?
Both endocrine (insulin and glucagon) and exocrine (digestive enzymes)
What are hormones?
Chemical messengers from the endocrine glands that travel in blood placing them in direct contact with all the cells
How much receptor does each cell have?
2,000 to 10,000 specific receptors
What are steroid hormones?
Lipid soluble
Diffuse easily through cell membranes
Receptors located within the cell
Derived from cholesterol
What gland secretes the steroid hormones?
Adrenal cortex, ovaries, testes, and placenta
What are nonsteroid hormones?
Nonlipid soluble
Cannot easily diffuse through cell membrane
Receptors located on cell membrane
What are the two types of nonsteroid hormone?
Amino acid derivatives (epinephrine) AND
Protein OR Peptide hormone (insulin)
What controls hormone release?
Plasma levels of specific hormones fluctuate
Secretion is regulated by a negative feedback system
Cells can also alter their number of hormone receptors via up- and down-regulation
What is down regulation?
Decrease in number of cell receptors
Less hormone can bind to the cell and higher concentrations of the hormone remain in the blood plasma
What is up regulation?
Increase in number of cell receptors
More hormone can bind to the cell and lower concentrations of the hormone remain in blood plasma
Classification of steroidal type hormone
Lipid soluble and formed from cholesterol
Classification of nonsteroidal type hormone
Nonlipid soluble and formed from amino acids, peptides, or proteins
How does hormones travel and work in the body?
They are secreted in the blood and travel to sites where they exert an effect on only those target cells that have receptors specific to that hormone
How do steroids synthesize protein?
via a process called direct gene activation
What regulates most of the hormone?
Negative Feedback System
How does nonsteroid hormones travel and work in the body?
Binds to receptors on the cell membrane, which triggers a second messenger within the cell, which in turn triggers numerous cellular processes
Hormones of the pituitary gland: ANTERIOR LOBE
Growth hormone, Thyrotropin, Follicle-stimulating hormone, Luteinizing hormone, Prolactin, Adrenocorticotropin
Hormones of the pituitary gland: POSTERIOR LOBE
Antidiuretic hormone and oxytocin
What are the effects of growth hormone?
Promotes muscle growth and hypertrophy by facilitating amino acid transport
Directly stimulates fat metabolism (lipolysis)
When are levels of growth hormone elevated?
During aerobic exercise in proportion to exercise intensity
Hormones of the thyroid gland
Triiodothyronine (T3) and thyroxine (T4)
Calcitonin
What does calcitonin do?
Decreases plasma calcium concentration
Acts primarily on bones and kidneys
Parathyroid gland hormone?
Parathyroid hormone
What does PTH (Parathyroid Hormone) do?
Regulates plasma calcium and plasma phosphate concentrations by targeting the bones, intestines, and kidneys
Adrenal Medulla hormones?
Catecholamines (epinephrine and nonepinephrine)
Mineralocorticoids (includes aldosterone)
Glucocorticoids (includes cortisol)
Gonadocorticoids (includes androgens, estrogens, and progesterones)
Catecholamines helps stimulate the sympathetic nervous system to help with what?
Prepare you for immediate action
Catecholamines increases what?
Rate & force of heart contraction Blood pressure Respiration Metabolic rate Glycogenolysis Release of glucose & FFA into blood
How does catecholamine allow more blood to go to the skeletal muscles?
Through vasodilation and vasoconstriction of specific vessels
What does mineralocorticoids do?
Maintain electrolyte balance in extracellular fluid
What does glucocorticoids do?
Maintain consistent plasma glucose levels between meals
What does gonadocorticoids do?
Released in addition to those released by reproductive organs but in lesser amounts
What are the hormones of the pancreas?
Insulin and glucagon
What does insulin do?
secreted when glucose plasma levels are elevated (hyperglycemia)
What does glucagon do?
Secreted when plasma glucose concentrations are below normal (hypoglycemia)
What are the reproductive hormones?
Estrogen
Androgen (i.e. testosterone)
Progesterone
Hormones released by kidneys?
erythropoietin and renin
What does renin do?
it is a hormone and enzyme involved in blood pressure control and fluid & electrolyte balance
What does erythropoietin do?
Regulates red blood cell production by stimulating bone marrow
Important in our adaptation to training and altitude
Hormones that increase glucose metabolism
Glucagon
Epinephrine
Nonepinephrine
Cortisol
What happens when your carbohydrate reserves are low?
The hormones accelerate the oxidation of fat to ensure that your muscles have enough energy to use.
What does androgens do?
Produces androgenic characteristics during puberty
Builds muscle, bone mass, strength, & libido in men
Increase protein synthesis
How do you increase androgens?
Increase by exercise/resistance training
Endurance training results in no change or decrease
What do estrogens do?
Menstrual cycle in women
What is menstrual cycle?
Monthly bleeding for 3-5 days
Shedding of lining of uterus
Prepares women’s body for pregnancy each month
What is ovulation?
day 14 of 28, egg leaves ovary, is transported to uterus via fallopian tube
what is Dysmenorrhea?
painful period with severe cramping
What is amenorrhea?
Lack of mentrual period
Possible causes of amenorrhea?
pregnancy, breast feeding, extreme weight loss, eating disorder, stress, excessive exercise
What is menorrhagia?
Prolonged (>7days) menstrual bleeding with clots
What is premenstrual syndrome? (PMS)
Highly variable symptoms 7-14 days before period
Exercise might diminish symptoms
What is Insulin-Like Growth Factors?
Super family of peptides
Major forms: IGF-I and IGF-II
Where are Insulin-Like Growth Factors secreted from?
Endocrine, paracrine, and autocrine releases
What are the functions of the Insulin-Like Growth Factors?
Have important anabolic functions for muscle and bone
Have 6 known binding proteins
Signals for protein synthesis
Exercise response and adaptations
What are the functions of binding proteins?
Extend half-life of IGFs in circulation
Transport IGFs to target cells
Help modulate biological actions of IGFs
What is the nickname of adrenal gland?
“Fight or flight” gland
Where is adrenal gland located?
On top of the kidney
What are the two functional parts of the adrenal gland?
adrenal cortex and adrenal medulla
