regulation of hormone secretion into blood

Question 1

humoral stimulus

Answer 1

stimulus is released in response to changes in ion con. or nutrient level in blood

Question 2

humoral stimulus e.g 1
INCREASE BLOOD GLUCOSE ( AFTER EATING CARBS )

Answer 2

pancreatic B-cells ( of islets of langerhans ) detect glucose and release insulin - > decreases blood glucose

Question 3

humoral stimulus e.g 2
DECREASE BLOOD Ca+

Answer 3

parathyroid gland detects decrease in Ca+ and releases parathyroid hormone => increase bone resorption (breakdown) by - decrease osteoblast activity and increase in osteoclast activity => increases blood Ca+

Question 4

neural stimulus
e.g. 1 Heart Rate (HR)

Answer 4

1. at rest - heart is stable
2. then it experiences a stimulus activating SNS

3.SNS sends signals by preganglionic neurons using nt = acetylcholine (ach) directly to adrenal medulla

4.adrenal medulla releases epinephrine + norepinephrine (NE)

5. causing INCREASE HR + FORCE OF CONTRACTION

Question 5

neural stimulus
e.g. 2 uterine contractions

Answer 5

1. uterine contractions stimulate -> hypothalamus which signals the post. pituitary
2. post. pituitary releases oxytocin
3. release of oxytocin further stimulate uterine contraction = +ive fb, where contractions intensify until childbirth

Question 6

hormonal stimulus
e.g metabolism

Answer 6

low metabolism

1.hypothalamus releases thyrotropin releasing hormone (TRH)

2. TRH stimulates ant. pituitary to release thyroid stimulating hormone (TSH)
3. TSH acts on thyroid gland

4.thyroid gland secretes thyroxin (T4)

5.T4 converted to T3 (in target tissue/liver)

= increase in metabolism
=-ive fb