Endocrine system Flashcards
What is the endocrine system mostly comprised of?
Glands
What are secreted by the glands in the endocrine system?
Hormones are secreted in the blood stream where a target cell has a receptor for
How does the endocrine system compare to the nervous system?
The nervous system is fast but results fade quickly while the endocrine system is slower but has more prolonged responses
What are the major parts of the Endocrine system? (11ish)
The Hypothalamus
The Pituitary Gland (posterior and anterior)
The Pineal gland
The Thyroid
The Parathyroids
The Thymus
The Adrenal gland & cortex
The Pancreas
The Gonads (Testes & Ovaries)
The Kidney and Heart
What are the three classes of hormones?
Peptide/protein hormones
Steroid hormones
Amino acid derivatives
What are examples of Peptide/protein hormones?
Insulin, glucagon, leptin
What are steroid hormones derived from?
Cholesterol
What are steroid hormones? Example?
They are lipids that enter a cell’s nucleus and affect gene activity (thus protein systhesis) Ex. Testosterone
Where do amino acid derivatives derive from?
Tyrosine
What does the posterior pituitary gland do?
It stores (doesn’t produce) ADH (Antidiuretic) and Oxytocin made by the hypothalamus
What does ADH do?
It regulates water balance by reabsorbing water into the bloodstream
What does Oxytocin do?
It causes uterine contractions during childbirth and allows milk to be released during nursing (It’s also a positive feedback loop)
What does the Anterior pituitary gland do?
It controls other hormones and is controlled by the hypothalamus
What hormones are produced by the anterior pituitary gland?
- TSH (Thyroid-Stimulating hormone) which stimulates the thyroid to produce thyroid hormones
- ACTH (Adrenocorticotropic hormone) which stimulates the Adreanal cortex to produce cortisol
- Gonadotropic hormones which stimulate gonads to produce sex cells and hormones
- PRL (Prolactin) which stimulates mammary glands to develop and produce milk only after childbirth
- Melanocyte-stimulanting hormone (MSH) which causes skin color changes
- GH (Growth hormone) which promotes skeletal and muscular growth
What are affects of too much or too little growth hormone?
Pituitary dwarfism - too little GH is produced during childhood
Gigantism - too much GH is produced during childhood (often times results in poor health)
Acromegaly - overproduction of GH as an adult which results in larger than normal feet, hands, and face
What is needed to allow the thyroid gland to produce its hormones?
Iodine
What does the Thyroid gland do?
It produces TH (thyroid hormone) which regulates metabolism
What is is called when there are low blood levels of thyroid hormones?
Hypothyroidism
What is it called when there are excess thyroid hormones in the blood?
Hyperthyroidism
What is congenital hypothyroidism?
It occurs when the thyroid doesn’t develop properly and is characterized by a short stocky person (may have mental retardation)
What is Myxedema?
It is hyperthyroidism in adults that is characterized by lethargy, weight gain, loss of hair, cold intolerance, and thick puffy skin
What is Exophthalimic goiter?
It is characterized by enlargement the thyroid gland and protruding eyes
What do the parathyroid glands do?
They produce PTH (parathyroid hormone) which cause blood ca2+ levels to increase by promoting osteoclast activity
What are the two parts of each adrenal gland? What are they controlled by?
The Adreanal medulla (inner) controlled by the nervous system
The Adreanal cortex (outer) mostly controlled by ACTH made by the anterior pituitary
What stimulates hormone secretion from in the adreanal medulla?
The Hypothalamus
What two hormones are made by the Adreanal medulla?
Epinephrine and Norepinephrine
What are the two main types of hormones made by the adreanal cortex?
Glucocorticoids and Mineralocorticoids
What do Glucocorticoids do? Examples?
They regulate carbohydrate, protein, and fat metabolism
They also suppress the body’s inflammatory response
Ex. Cortisol and Cortisone
What do mineralocorticoids do? Example?
They regulate salt and water balance
Ex. Aldosterone (targets the kidney)
What is Addison disease?
Caused by hypo secretion of glucocorticoids by the adreanal cortex (characterized by bronzing of the skin)
What is Cushing syndrome?
It is caused by hyper secretion of glucocorticoids by the adrenal cortex, (characterized by weight gain in the trunk of body but not arms and legs)
What is special about the pancreas?
It’s composed of two different types of tissues
What are the exocrine tissues in the pancreas?
Acinar cells which produce and secrete digestive juices
What are the two hormones of the endocrine cells of the pancreas? What do they do?
Insulin - secreted by beta cells when blood glucose is high (stimulates the uptake of glucose by cells)
Glucagon - secreted by alpha cells when blood glucose is low (stimulates the break down of glycogen in the liver)
What is diabetes and what are the different types?
Diabetes is the inability to control blood glucose levels
There’s type 1, type 2, and gestational
What are some facts about type 1 diabetes?
It’s normally has early-onset
Tends to be genetic
Pancreatic cells are attacked and cannot produce insulin thus requiring artificial injections
What are some facts about type 2 diabetes?
Normally an adult-onset (most common type)
Tends to occur in obese sedentary people
Cells do not respond to insulin
Usually diet and exercise are important for controlling this and may even prevent it
What is gestational diabetes
It occurs during pregnancy
What is produced by testes?
They produce androgens which:
Stimulate growth of penis and testes
Create male sec characteristics (like hair)
Prompts the larynx and vocal cords to enlarge (lower voice)
Promotes muscular strength
What are produced by ovaries?
They produce estrogen and progesterone which:
-Stimulates growth of vagina and uterus
-Responsible for secondary sex characteristics
-Responsible for egg maturation
-Regulate the urine cycle
Where is the Thymus found?
Beneath the sturnum
What mature at the Thymus
T lymphocytes
What hormones do the Thymus secrete?
Thymosins (aid in differentiating lymphocytes)
What does the pineal gland do?
It secretes melatonin and regulates the circadian rhythm
What are some other important hormones secreted by cells
Erythropoietin (EPO) is secreted by the kidneys to increase red blood cell production
Leptin is produced by fat cells and provides a feeling of being satiated
Prostaglandins have many roles in the body and are not found in the bloodstream because the only affect neighboring cells
What’s important to know about peptide/protein hormones?
They require second messengers (since they cannot pass through the membrane)
