Endocrine System Flashcards
Negative Feedback Loop
- Simplified: Organ releases a hormone to a target, target acts, sends signal back to organ.
- Detailed:
When a level of a specific hormone drops below needed levels, the appropriate endocrine gland is stimulated to produce more hormone. Once the proper hormone level is present in the blood stream, stimulation of that endocrine gland is reduced and hormone production is reduced
Major endocrine glands (9)
- Anterior pituitary (cranial)
- Posterior pituitary (caudal)
- Thyroid
- Parathyroid
- Adrenal cortex
- Adrenal medulla
- Pancreas
- Testis
- Ovary
Anterior pituitary (cranial) hormones (7)
- Growth hormone (GH)
- Prolactin
- Thyroid-stimulating hormone (TSH)
- Adrenocorticotropic hormone (ACTH)
- Follicle-stimulating hormone (FSH)
- Luteinizing hormone (LH)
- Melanocyte-stimulating hormone (MSH)
Posterior pituitary (caudal) hormones (2) & function
- Stores hormones from the hypothalamus, but does not produce them.
1. Antidiuretic
2. Oxytocin
Thyroid gland
(iodine is essential for producing these hormones)
- T3
- T4: Influences growth and development of muscles/bones.
- Calorigenic effect - regulates metabolic rate of all the body’s cells. Generate and maintain heat. Effects metabolism of proteins, carbs, & lipids.
Parathyroid hormone location and function
- Location: On top of the thyroid.
- Function: Maintain blood calcium levels. Prevents hypocalcemia.
Adrenal glands location
Near cranial ends of the kidneys
Adrenal cortex (OUTER gland)
Hint: “the deeper you go, the sweeter it gets”
Produces 3 steroid hormones:
1. Mineralocorticoids: Regulates electrolytes. (salts)
2. Glucocorticoids: Hyperglycemic effect (glucose levels rise). Maintain blood pressure & helps resist effects of stress. (sugar)
3. Sex hormones: Androgens (male) and estrogens (female).
Adrenal medulla (INNER gland) hormones & function
- Produces epinephrine and norepinephrine.
- Secretion is controlled by sympathetic portion of autonomic nervous system.
- Increases HR & output, blood pressure, dilates air passageways in lungs. Decreases GI function.
Pancreas location and function
- Location: Near duodenum
- Function: Both exocrine and endocrine functions.
- Pancreatic islets: alpha cell (produce glucagon), Beta cell (produce insulin, allows glucose absorption), Delta cell (produce somatostatin AKA growth hormone).
Pancreatic hormones
- Insulin: lowers blood glucose levels by having glucose, AA, & fatty acids be absorbed into body cells
- Glucagon: lowers blood glucose levels by stimulating lover cells to convert glycogen to glucose and stim. gluconeogenesis
- Somatotropin (growth hormone): “emergency brake” inhibits secretion of insulin, glucagon, and GH.
Testes hormone & function
- Produce androgens (male hormones) when stim. by LH.
- Testosterone: provides for development of male secondary sex chara and accessory sex glands. Activates spermatogenesis (sperm production).
Ovaries hormones & function
- Produces estrogen and progestin hormones
- Progestin: during pregnancy, hormone is sent from uterus and corpus luteum is maintained. No pregnancy, corpus luteum will shrink/disappear.
Pituitary glands location & structure
- Hangs off of the brain (like testicles)
- Two separate glands with different structures and functions.
1. Anterior (cranial) - adenohypophysis; rostral portion.
2. Posterior (caudal) - neurohypophysis; caudal portion.
Thyroid gland structure/location
Two lobes on either side of the larynx
Calcitonin
Hint: think about what the basics of Ca+ do for the body
- Produced by C cells located between thyroid follicles.
- Helps maintain blood calcium levels
- Involved in muscle contraction, clotting, milk secretion, & formation and maintenance of skeleton
Kidneys hormones
Fun fact: this isn’t an endocrine gland!
- Produce erythropoietin - stim red bone marrow to increase production of RBC
- Process can also be stim by hypoxia
- RBC production increases, more O2 feeds back into kidneys & slows erythropoietin production.
Stomach hormones
- Gastrin: produced by cells in the wall of the stomach. “Oddball” hormone.
- Secretion stim by presence of food in stomach (also w/scent of food).
Placenta hormones
- Surrounds a developing fetus (barrier & unifier between mother and offspring)
- Produces hormones to support & maintain pregnancy
1. Estrogen
2. Progestin
3. Chorionic gonadotropin (some species)
Small intestine
(Just need to know it’s in the endocrine system)
Secretin & cholecystokinin produced by cells in lining of small intestine
Pineal hormone
“Primative eye”
- Located caudal end of the cleft that separates the two cerebral hemispheres.
- Melatonin: hormone like substance that seems to affect moods & sleep-wake cycles.
Thymus
Hint: Large in young animals, small in adult
- Location: Extends cranially from the level of the heart up into neck region along both sides of the trachea.
- Function: Hormones, or hormone like, chemical substances.
This hormone stimulates uterine contractions
Oxytocin
This hormone lowers blood glucose
Insulin
