Endocrine 2

Question 1

Answer 1

Question 2

Pituitary Gland

Answer 2

• located at the base of the Brian and is attached to the hypothalamus
• the hypothalamus controls the secretion of pituitary hormones (when activated by neural input, the hypothalamus stimulates the pituitary gland to secrete hormones)
• some pituitary hormones stimulate target cells and some stimulate the secretion of hormones by other endocrine glands
• has two parts: anterior lobe and posterior lobe
• each part has a distinctive mechanism for hormone secretion

Question 3

Posterior lobe of the pituitary gland

Answer 3

• connected the the hypothalamus by neurons
• secretes hormones into blood

Question 4

How does the hypothalamus communicate with the posterior pituitary

Answer 4

• the hypothalamus is connected to the posterior lobe by neurons: cell bodies in the hypothalamus, axons terminate in the posterior lobe.
• posterior pituitary hormones - are made in the hypothalamus (cell body of neuron), travel down the axon, and are stored at the axon endings until requires (peptide hormones)
• the hypothalamus uses neural communication with the posterior lobe to release hormones into the blood: results in an increase or decrease of frequency of action potentials leads to a corresponding change in hormaone release
• Antidiuretic hormone (ADH) or oxytocin released into blood

Question 5

Hormones released by posterior pituitary

Answer 5

• antiduereitc hormone
• oxytocin

Question 6

Antidiuretic hormone

Answer 6

• stimulates the kidneys to reabsord water (the kidneys conserve water when the body dehydrates)

Question 7

Oxytocin

Answer 7

• stimulates the contraction of uterine muscles during childbirth (an example of positive feedback)
• stimulates milk release in breastfeeding (mild ejection reflex )

Question 8

Where are the two hormones made

Answer 8

Both hormones are Mede in the hypothalamus and stored int the posterior pituitary until required

Question 9

Anterior love of the pituitary gland

Answer 9

Connected to the hypothalamus by blood vessels
- hypothalamus hormones stimulate or inhibit release of stored hormones form specific anterior pituitary cells

Question 10

How does the hypothalamus communicate with the anterior pituitary
I don’t understand this one

Answer 10

Stimulus: neural input within hypothalamus
- hypothalamus signals the anterior pituitary to release hormones by hormonal stimulation, secreting stored releasing hormone (or inhibiting hormone)
- hormone binds to receptor on membrane of a specific cell type and a specific anterior pituitary hormone is secreted e.g. prolactin, growth hormone

Question 11

Answer 11

Question 12

Feedback regulation of the anterior pituitary gland- HOW EFFECT IS TURNED ON

Answer 12

Stimulus

Hypothalamus releases releasing hormone that travels through portable blood system down the anterior pituitary gland
Anterior putiotary gland releases the pituartay hormone that travels through the blood and around the body to a target organ or tissue
Target organ releases another hormone - this is the hormone that goes on and has the effects

Question 13

Feedback regulation of the anterior pituitary gland- HOW EFFECT IS TURNED OFF

Answer 13

• 3rd hormone will negatively impractical the anterior punitary gland and the hypothalamus from releasing their hormones

Question 14

Anterior pituitary hormones

Answer 14

(Many others as well)

Question 15

Growth hormone controlled release - NEGATIVE FEED BACK INHIBITION

Answer 15

• IGF-1 inhibits the release fo further GHRH
• IGF-1 encourages the releases of GHIH, which will then inhibit the release of growth hormone from the anterior putirtary

Question 16

Growth hormone has ____ actions and in____ actions

Answer 16

Anterior pituitary growth hormone has direct effects on the function of liver muscle and fat as well as indirect effects through the actions of IGF-1

Question 17

Direct effects of GH

Answer 17

Muscle: stimulates protein synthesis (long term) and inhibits cellular uptake of glucose (short term)

Liver: stimulates glucose synthesis (short term)

Fat: increases triglyceride breakdown in adipose tissue (short term)

Question 18

Indirect effects of GH

Answer 18

Promotes the growth of bones, muscle and other tissues by release of somatomedin C, which promotes cell division (long term)

Question 19

GH has a _____ effect on ____ and ______ effects on ______

Answer 19

GH has a long term effect on growth ( cos IGF-1promotes cell division) and short term effects on metabolism

Question 20

Pattern of growth hormone secretion over a day

Answer 20

GH concentrations have peaks and troughs throughout the whole day

GH concentrations are highest during sleep

Question 21

Pattern of growth hormone secretion over a life time

Answer 21

• GH concentrations are higher in children then adults, with a peak period during puberty
• GH secretion declines with aging

Question 22

Sum

Answer 22

Question 23

Growth hormone controlled release

Answer 23

• hypothalamus decides if a response is needed
• hypothalamus releases GH-RH from GHRH neurons into portal blood system
• causes anterior pituitary to release growth hormone
• growth hormone travels through the systemic circulation and that will act on the liver
• causes liver to release somatomedin C (IGF-1) - EFFECTOR

Question 24

Answer 24

Question 25

Answer 25

Question 26

Growth hormone feedback loop

Answer 26

Hypothalamus (after it has inrergrated information about whererter or not a response is needed) will release GHRH into portal blood vessels

This causes the anterior pituitary gland to release growth hormone

Growth hormone travels through the systemic circulation and will act upon the liver causing the release of somatomedin C (IGF-1)

Effects in body