Flashcards in Endocrine System Deck (57):
Describe the overall function of the endocrine system
Reproduction, growth and development, internal homeostasis, helps to cope with environmental changes
Contrast endocrine and exocrine glands
-exocrine release content into ducts or skin surface Ex salivary
-endocrine release horemone into blood stream
Define hormone and target cell.
-Hormone is made by an endocrine gland & is a chemical messenger traveling in the bloodstream.
-The target cell responds to the hormone because it has matching receptors for the hormone
Describe the structure and transport mechanism of hormones
-organic, amino acid (some lipid-reproduction)
-transported in the bloodstream; usually they are attached to some carrier protein making them physically larger so that they are not urinated out.
Explain how a hormone affects the activity of target cells
-It can go to the nucleus and act upon the genes
-or it can stimulate and intermediate compound such as cAMP, which acts as a second messenger and stimulates or inhibits a process or metabolic pathway in the cell. (assisting in chain reaction)
Identify the location of the pituitary gland
- in Sella Turcica of sphenoid bone
Describe the 2 lobes of the pituitary gland, include which hormones are released by each lobe and their function
-FSH causes sperm production in male and follicle maturation in female
-LH=ICSH causes interstitial cells of testes to make testosterone in male and causes ovulation in female
-TSH stimulates the thyroid gland to make hormone
-ACTH stimulates the adrenal cortex to make hormone
-GH causes growth
-Prolactin causes milk production in females
-MSH causes skin pigment (melanin) to be produced.
(endorphins not hormone, but released here)
Neurohypophysis- posterior lobe (doesn't make hormones, stores and releases hormones from hypothalamus
-ADH-antidiuretic water reabsorption (from urine to blood) in kidney
-Oxytocin-contractions milk let down
-peptides made by adenohypophysis in addition to the hormones that has
-not a hormone but is really a neuromodulator
-Morphine like compound made by anterior pituitary gland
Describe the controls of the pituitary gland
-.Hypothalamus makes stimulatory hormones called releasing hormones and inhibitory hormones; Negative feedback
Explain why the posterior pituitary is not a TRUE endocrine gland
It doesn't make ADH and Oxytocin. They are made by hypothalamus but stored and released by posterior pituitary.
Describe the location and histology of the thyroid gland
-inferior to larynx
-follicles filled with thyroid hormone (colloid), and the surrounding follicle cells make the hormone.
-The interstitial cells are called parafollicular cells and make calcitonin (controls calcium levels)
Name and describe the formation and function of thyroid hormones
-Made from an amino acid called tyrosine.
-Three iodine molecules in T3 and four in T4.
Describe how thyroid hormones are transported in the bloodstream
-the thyroid hormone is transported on plasma globulin TBG
Describe the controls over thyroid hormone synthesis and release
-synthesized by iodine (only place in body) combining with Tyrosine to make T4 (90%) and T3 (10%)
- Regulates metabolic rate
-Negative feedback, TSH from anterior pituitary and Thyroid releasing hormone from hypothalamus.
Name the gland and cell that make calcitonin
-Parafollicular cells of the thyroid- C Cells
Describe the function and control of Calcitonin
-Decreases Calcium and phosphate in blood stream
-Important because Calcium controls muscle contraction, too much can cause heart attack
Describe the location of the parathyroid gland and the function of its hormone and the controls of its release
-Embedded in the thyroid gland. (4 of them)
-It makes Parathyroid hormone which increases blood calcium levels.
-Obviously, blood calcium levels determine whether PTH or Calcitonin should be released.
Describe the location and the 2 portions of the adrenal gland
-Superior to Kidney
-Adrenal Medulla (epinephrine and norepinephrine)
Name the three layers of the adrenal cortex. Name and describe the effects of the hormones made by each layer. Describe the controls of their release
-Outer is the zona glomerulosa
-aldosterone is made which causes sodium reabsorption in the kidneys (sodium goes from urine back to blood, and water passively follows)
-Zona fasciculata is middle layer
- making glucocorticoids that help one deal with long term stress by conserving energy for later.
-It is also anti-inflammatory.
-Inner zone is zona reticularis
-making sex hormones to be discussed under reproduction.
-Of course ACTH from the ant. pituitary stimulates the release of these hormones. Also, low blood sodium would stimulate release of aldosterone. If your blood pressure is low, the kidneys release renin. Renin is an enzyme that converts angiotensinogen to angiotensin. These will be discussed under cardiovascular system. However, angiotensin can cause the adrenal cortex to release aldosterone. Since aldosterone causes more salt to be in the bloodstream, and water passively follows, it will help to restore the low blood pressure to a more normal value.
Define islets of langerhans, pancreatic islets, and chromaffin cells
-Islets of Langerhans = pancreatic islets and are the endocrine cells of the pancreas.
-The chromaffin cells are the endocrine cells of the adrenal medulla.
Name the organ that has both exocrine and endocrine functions
Describe the location and structure of the pancreas
- Behind the stomach, along the duodenum
Name the cells that make insulin, glucagon, and somatostatin, describe their effects.
-Beta (islet) cells make Insulin- Lowers blood glucose by allowing it to go into cells
-Alpha cells make Glucagon- Raises blood glucose by bringing it out of storage
-Delta cells make Somatostatin- Inhibits GH release
Describe the controls of insulin and glucagon release
-High blood glucose leads to insulin release
-Low blood glucose leads to glucagon release.
-They are released in urine
- glucose level is 0 at homeostasis.
-GI hormones- meal time and in between meals
Name the male and female gonads and briefly describe their endocrine roles.
-Ovaries- Estrogen and progestrone
Describe the location and function of the pineal gland
-roof of third ventricle.
-Makes melatonin (color pigment) which depresses reproductive activity
Name the gland that is replaced by connective tissue and fat in adults. Briefly describe its location and function.
-Thymus. superior to cerebellum (calcifies with age)
-It has a lymphatic role, in that T lymphocytes are made and "trained" here.
-The endocrine role is that it releases thymic hormone to stimulate these T cells. (immunity)
Describe the structure and function of prostaglandins
-Unique group of hormones because made from fatty acids
-promote pain (how tylenol works)
-They are unique in that they tend to act locally. -For example, a prostaglandin released by the uterus into the bloodstream has target cells in the uterus and acts upon the uterus.
name the two hormones made by the adrenal medulla and describe their functions and the controls of their releases.
-Epinephrine & Norepinephrine are released under fight of flight situations.
-They exaggerate the fight or flight response. Mostly, epinephrine is released.
-Follicle stimulation hormone- stimulates follicle development in ovaries, stimulates sperm production and maturation in male
-Luteinizing hormone results in ovulation in female, Interstitial cell stimulating hormone results in testosterone production
Thyroid stimulating hormone
-Adrenocorticotropic hormone (above kidney cortext stiumulating)
-initiates and maintains milk production in female
-Melanocyte stimulates skin pigment
-Posterior Pituitary (hypothalamus)
-water reabsorbtion from kidney to bloodstream
--Posterior Pituitary (hypothalamus)
-Quick birth, uterine contractions for child birth
t4 and t3
Thyroid hormones are carried in the plasma bound to this globulin
TSH and TRH
Plays role in reproduction
-negative feedback loop
-decreases calcium and phosporase
-increases ca and decreases p
Epinephrine and norepinephrine
- Adrenal gland
in the medulla
glucose (SNS, endocrine)
-made by liver
-group of hormones that deal with long term stresses
- anti inflammatory
-adrenal cortex- zona fasciculata
-lowers blood glucose
-raises blood glucose
-inhibits growth hormone
Estrogen and Progesterone
-decreases reproductive activity
help develop t cells