Endocrine System Flashcards
Compare and contrast NS and ES
- NS: quick responses to rapid changes in external environment
- ES: slower acting - taking care of internal environment of body, maintaining homeostasis and controlling reproduction
Hypothalamus
region of diencephalon inferior to thalamus
Function: neural and endocrine signalling
Function of endocrine glands?
- Ductless glands
- secrete their hormones directly into surrounding fluid
- interstitial fluid and blood vessels then transport hormones throughout the body
Pituitary gland
- bean-sized organ suspended from hypothalamus (suspended by a stem called infundibulum).
- Cradled within sella turcic of sphenoid bone of the skull
- 2 lobes (anterior = glandular tissue, posterior = neural tissue)
- Function: produces, stores and secretes hormones
Thyroid gland
- butterfly-shaped organ
- location: anterior to trachea and inferior to larynx
- function: synthesis of thyroid hormones
Parathyroid glands
- Small, round glands embedded in posterior thyroid gland
- Most people have 4, but some may have more
- function: produces parathyroid hormone to regulate blood Ca levels
Adrenal (suprarenal) glands
- Wedges of glandular and neuroendocrine tissue attached to superior surface of the kidneys by a fibrous capsule
- function: secrete epinephrine (adrenaline) and norepinephrine (noradrenaline) which stimulate the fight or flight response
Pineal gland
Endocrine gland that secretes melatonin (sleep-wake)
Pancreas
- Location: posterior to stomach
- organ with both exocrine and endocrine functions
- Pancreatic islets: clusters of cells secrete glucagon and insulin (together they regulate blood glucose levels)
Major hormones of anterior pituitary
- Growth hormone (GH): growth of body tissues
- Thyroid-stimulating hormone (TSH): stimulates thyroid hormone release
- Follicle-stimulating hormone (FSH): simulates gamete production
- Luteinising hormone (LH): stimulates androgen production by gonads
Major hormones of thyroid
- Thyroid hormones: stimulate basal metabolic rate
- Calcitonin: reduces blood Ca2+ levels
Major hormone of parathyroid
Parathyroid hormone (PTH): Increases blood Ca2+ levels
Major hormone of adrenal (medulla)
Epinephrine / norepinephrine : stimulate fight or flight response
Major hormone of pineal gland
Melatonin: sleep-wake cycles
Major hormones of pancreas
- Insulin: reduces blood glucose levels
- Glucagon: increases blood glucose levels
Major hormones of testes
Testosterone: stimulates development of male secondary sex characteristics and sperm production
Major hormones of ovaries
Oestrogens and progesterone: stimulate development of female secondary sex characteristics and prepare the body for childbirth
Major hormone of posterior pituitaty
- Antidiuretic hormone (ADH): stimulates water reabsorption by kidneys
Posterior pituitary
- extension of neurons of hypothalamus
- Cell bodies rest in hypothalamus, but their axons descend through the infundibulum, and end in the posterior pituitary
- does not produce hormones, but rather stores and secretes hormones including antidiuretic hormone produced by the hypothalamus
Testes
- male gonads
- paired ovals located in the scrotum
- produce testosterone
- both endocrine and exocrine
Ovaries
- female gonads
- paired ovals located in pelvic cavity
- secrete oestrogens and progesterone
- exocrine and endocrine glands
