C16 12-16

Question 1

12. Describe structural relationships between the hypothalamus and the pituitary gland.

Answer 1

Connected by the Hypothalmic hypophyseal tract (posterior pituitary) and the hypophyseal portal system (anterior pituitary).

Question 2

12. Describe functional relationship between the hypothalamus and the pituitary gland.

Answer 2

Hypothalamus is the “master of the master”.

1. it makes OXT and ADH
2. It makes regulatory hormones, both releasing (GnRH) and inhibiting.

Question 3

Hypothalmic hypophyseal portal system?

Answer 3

Primary capillary plexus in the infundibulum –> hypophyseal portal veins –> secondary capillary plexus in the anterior lobe.

Question 4

What is special about the hypothalamus and pituitary gland?

Answer 4

They function together to regulate almost every body system.

Question 5

Why is the hypothalamus considered a primary endocrine gland?

Answer 5

Because even though it is nervous tissue, it secretes several hormones (most of which affect the pituitary gland).

Question 6

Who is the master gland?

Answer 6

The hypothalamus is the master of the master which is the pituitary. Many endocrine glands are controlled by the hypothalamus, including the pituitary.

Question 7

Anatomy of the pituitary?

Answer 7

Found in the sella turcica of the shpenoid.

Infundibulum (stalk) connects,

Anterior is 3/4 “adenohypophysis” which is made of glandular tissue from the oral mucosa, upward growth

Posterior is 1/4 “neurohypophysis” - not a true gland, but a mass of neuroglia (pituicytes), downward extension of the hypothalamus.

Question 8

Physiology of the pituitary?

Answer 8

Anterior: synthesizes and releases 6 hormones. Posterior: stores and releases 2 neurohormones from hypothalamus.

Question 9

TP FLAG

Answer 9

TSH, prolactin, FSH, LH, ACTH (adrenocorticotropic), GH

Question 10

Hypothalamus - posterior pituitary

Answer 10

Connected by the Hypothalmic hypophyseal tract

Question 11

Hypothalamus - anteriour pituitary

Answer 11

Connected by the hypophyseal portal system (anterior pituitary).

Question 12

Where are ADH and OXT synthesized?

Answer 12

Supraoptic nucleus - ADH (aka vasopressin or AVP), Paraventricular nucleus - OXT

Question 13

How do neurohormones travel from hypothalamus –> post. Pit –> bloodstream?

Answer 13

Cells in the paraventricular or supraoptic nuclei synthesize ADH or OXT.
ADH/OXT are transported along the axons of the cells to the post. pituitary and stored in the axon terminals.
When the hypothalmic neurons fire, they release the stored homones into a capillary bed in the pp for distribution.

Question 14

How does the hypothalamus communicate with the anterior pituitary?

Answer 14

Hypothalamus and ant. Pit are not connected directly neurally - communication is done via the hypophyseal portal system.

Primary capillary plexus in the infundibulum –> hypophyseal portal veins –> secondary capillary plexus in the anterior lobe.

Question 15

3 steps of communication between the hypothalamus/ant. Pituitary

Answer 15

1. Hypothalmic neurons secrete releasing or inhibiting hormones into the primary capillary plexus.
2. hypothalmic hormones travel through portal veins to the anterior pituitary where they stimulate or inhibit release of hormones made in the anterior pituitary.
3. In response to releasing hormones, the ant.pituitary secretes hormones into the secondary capillary plexus which connects with the general circulation.

Question 16

4 steps of interaction between the hypthalamus/post.pituitary

Answer 16

1. Hypothalmic neurons synthesize AHD/OXT.
2. ADH/OXT travel down the axons of the HH tract to the post.pituitary.
3. ADH/OXT are stored in the axon terminals in the post.pituitary.
4. When associated hypothalmic neurons fire, Aps cause the release of ADH/OXT into capillary beds/bloodstream.

Question 17

Portal system?

Answer 17

Unique way of connecting two capillary beds. Primary cap bed –> portal veins –> secondary cap bed. SHORTCUT!

Question 18

13. List the hormones released from the hypothalamus that control the anterior pituitary and posterior pituitary.

Answer 18

GnRH (inhibiting and releasing hormones), OXT/ADH

Question 19

Hypothalmic regulatory hormones are ? based?

Answer 19

Amino acid, size varies

Question 20

OXT effects and targets

Answer 20

Uterine contraction (uterine smooth muscle), Milk let-down (milk producing glands), Bonding (neurotransmitter in brain). (Note: 1st 2 are positive feedback)

Question 21

ADH effects and targets

Answer 21

Inhibits or prevents urine formation (tubules of of kidneys) In extreme blood loss large amounts are released causing vasoconstriction (hence vasopressin).

Question 22

Which four ant.pituitary hormones are tropic?

Answer 22

TSH, ACTH, FSH, LH

Question 23

GH effects and targets

Answer 23

Indirect action/IGF: Growth (skeletal/muscle),

Direct action: release glucose (liver, anti-insulin effect), fat breakdown and release (adipose)

Question 24

TSH effects and targets

Answer 24

Stimulates normal development and secretory action of the thyroid (metabolism indirectly) (thyroid)

Question 25

ACTH effects and targets

Answer 25

Stimulate the release of cortisol (stress) and aldosterone (salt lover, Na+/K+ balance), (adrenal cortex)

Question 26

FSH effects and targets

Answer 26

Spermatogenesis, follicle growth, ova maturation (gonads)

Question 27

LH effects and targets

Answer 27

Spermatogenesis, release testosterone, ovulation (gonads)

Question 28

Prolactin effects and targets

Answer 28

Milk production (breast tissue)

Question 29

Tropic hormone?

Answer 29

Hormone that regulates the secretory action of another endocrine organ.

Question 30

C+C Anterior/Posterior pituitary

Answer 30

1. Nickname: Adeno Neuro
2. Hormones synthesized: TP FLAG NONE
3. Hormones released: TP FLAG OXT/ADH
4. Pathway: HH portal system HH Tract
5. Stimulus for release of hormones: Regulatory hormones AP’s