Endocrine System

Question 1

Compare and contrast NS and ES

Answer 1

• NS: quick responses to rapid changes in external environment
• ES: slower acting - taking care of internal environment of body, maintaining homeostasis and controlling reproduction

Question 2

Hypothalamus

Answer 2

region of diencephalon inferior to thalamus
Function: neural and endocrine signalling

Question 3

Function of endocrine glands?

Answer 3

• Ductless glands
• secrete their hormones directly into surrounding fluid
• interstitial fluid and blood vessels then transport hormones throughout the body

Question 4

Pituitary gland

Answer 4

• 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

Question 5

Thyroid gland

Answer 5

• butterfly-shaped organ
• location: anterior to trachea and inferior to larynx
• function: synthesis of thyroid hormones

Question 6

Parathyroid glands

Answer 6

• 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

Question 7

Adrenal (suprarenal) glands

Answer 7

• 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

Question 8

Pineal gland

Answer 8

Endocrine gland that secretes melatonin (sleep-wake)

Question 9

Pancreas

Answer 9

• 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)

Question 10

Major hormones of anterior pituitary

Answer 10

• 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

Question 11

Major hormones of thyroid

Answer 11

• Thyroid hormones: stimulate basal metabolic rate
• Calcitonin: reduces blood Ca2+ levels

Question 12

Major hormone of parathyroid

Answer 12

Parathyroid hormone (PTH): Increases blood Ca2+ levels

Question 13

Major hormone of adrenal (medulla)

Answer 13

Epinephrine / norepinephrine : stimulate fight or flight response

Question 14

Major hormone of pineal gland

Answer 14

Melatonin: sleep-wake cycles

Question 15

Major hormones of pancreas

Answer 15

• Insulin: reduces blood glucose levels
• Glucagon: increases blood glucose levels

Question 16

Major hormones of testes

Answer 16

Testosterone: stimulates development of male secondary sex characteristics and sperm production

Question 17

Major hormones of ovaries

Answer 17

Oestrogens and progesterone: stimulate development of female secondary sex characteristics and prepare the body for childbirth

Question 18

Major hormone of posterior pituitaty

Answer 18

• Antidiuretic hormone (ADH): stimulates water reabsorption by kidneys

Question 19

Posterior pituitary

Answer 19

• 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

Question 20

Testes

Answer 20

• male gonads
• paired ovals located in the scrotum
• produce testosterone
• both endocrine and exocrine

Question 21

Ovaries

Answer 21

• female gonads
• paired ovals located in pelvic cavity
• secrete oestrogens and progesterone
• exocrine and endocrine glands