Hypothalamus and PG

Question 1

How is the hypothalamus and posterior pituitary connected?

Answer 1

neurally via the pituitary lobe extending from the median eminence

Question 2

How do the hypothalamus and posterior pituitary gland communicate?

Answer 2

hypothaliac neurons release neuropeptides down the median eminence

Question 3

how are the hypothalamus and anterior pituitary gland connected?

Answer 3

vascularly, blood flows through the hypothalamic-hypophyseal portal into anteriror sinuses and down the pitutray stalk.

Question 4

what are the two classes of hypothalamic regulatory hormones?

Answer 4

Regulating hormones and inhibiting hormones

Question 5

describe the mode of action for hormone secretion

Answer 5

Neurosecretory gland stimulated –> releases hormone –> discharged into hypophyseal poral circulation

Question 6

What is the anterior pituitary gland also known as and where is it’s origin?

Answer 6

adenohyophysis - rathe’s pouch

Question 7

What are the main functions of the hypothalamus?

Answer 7

Control centre for hormone sectertion, hmoestatic regulation of food intake and fluid balance, emotions and patterns.

Question 8

What hormones does the anterior hormone secrete?

Answer 8

TSH, adrenocorticotropic hormone (ACTH), FSH and LH

Question 9

What hormones does the posterior pituitary gland release?

Answer 9

Oxytocin and ADH (AKA vasopressin)

Question 10

How is the secretion of hormones from the hypothalamus and pituitary gland regulated?

Answer 10

Neural, hormonal and enviromental regulation signals will ensure that rhythm is maintained (sleep and awake) and organs will send signals too.

Question 11

How many amino acids make up CRH and what is it’s purpose?

Answer 11

41, stimulates ACTH secretion which stimulate release of cortisol.

Question 12

What is the mechansims of action for CRH?

Answer 12

Binds to a GPCR on cell membrane -> acttvates a subunit –> cAMP –> Kinase A –> inc. Ca –> exocytosis

Question 13

How many amino acids make up TRH and what is its purpose?

Answer 13

3, stimulates TSH production

Question 14

Describe the mechanism of action for TRH

Answer 14

TRH binds to GPCR –> DAG/IP3 pathway triggered

Question 15

How many amino acids are in GHRH and what is its purpose?

Answer 15

43, stimulates GH secretion

Question 16

What is the mechanism of action for GHRH?

Answer 16

GRHR binds to G-protein –> activates G a subunit –> adenylyl cyclase –> cAMP (increased gene transcription and GH synthesis) –> Ca chanel opens –> releases GH

Question 17

How many amino acids in GnRH and what is its purpose?

Answer 17

10, releases the main sex hormones for our gonads.

Question 18

What are the two functions of Somatostatin?

Answer 18

Inhibits GH secretion via somatotrophs and inhibits TSH secretion via the thyrotrophs

Question 19

what is the mechanism of action for somatostatin?

Answer 19

GPCR binding –> activates G subunit a –> INHIBITS Adenlyl C –> decrease in cytosolic Ca –> diminishes response of somatotroph to GHRH

Question 20

what is the function of dopamine?

Answer 20

inhibiting factor and hormone of prolactin

Question 21

Where is dopamine secreted from and synthesised?

Answer 21

Dopaminergic neurons in hypothalamus

Question 22

Are the cells that secrete posterior pituitary hormones in the pituitary?

Answer 22

no

Question 23

What is the precursor molecule for ADH?

Answer 23

prepropressophysin

Question 24

what is the target tissue for ADH?

Answer 24

nephrons in kidney

Question 25

How are ADH and Oxytocin transported?

Answer 25

Transported down axons via axoplasmic flow

Question 26

What is the precursor of oxytocin?

Answer 26

preproxyphysin

Question 27

what is the target tissue of oxytocin?

Answer 27

lacating breast and uterus during pregnancy

Question 28

what are the functions of oxytocin?

Answer 28

stimulates milk ejection by producing contraction myoepitheal cells on the aveloi and ducts in mammary glands and creates rhythmic contractions to induce labour and regress uterus after delivery

Question 29

What is the name of the hypothalamic region where parvocellular neurons release hormones?

Answer 29

Secreted via the median eminence and into the hypothalami-hypophyseal portal vasculature

Question 30

What is the hypothalamic nuclei responsible for oxytocin production?

Answer 30

periventricular nuclei

Question 31

What is the hypothalamic nuclei responsible for ADH production?

Answer 31

supraoptic

Question 32

What is the target cell for TRH?

Answer 32

thyrotropin cells

Question 33

What is the target cell/organ for CRH?

Answer 33

adrenal cortex

Question 34

What is the target cell/organ for GHRH?

Answer 34

Pituitary somatotroph cells

Question 35

What is an example of a primary disorder?

Answer 35

Thyroid Gland not functioning: not responding to TSH and decreased overall T4 and T3 levels. The pituitary gland still working (secondary) as is secreting TSH and the Hypothalamus (tertiary) is still regulating the response. Therefore is primary.

Question 36

What is the Target Cell of GnRH?

Answer 36

gonadotropic cells

Question 36

What is a Secondary Disorder example?

Answer 36

When an issue with the Pituitary Gland

Question 37

Describe how blood is supplied to the pituitary gland.

Answer 37

Blood enters the hypothalamus via the superior hypophysial arteries. The primary Capillary plexuses (capillary network) in the medical eminence distribute this blood via the hypothalamic-hypophyseal long portals. these portals pour blood into the anterior and pituitary sinuses.

Question 37

What is the hypothalamic-hypophyseal long portal vessels' function?

Answer 37

it is a mechanism for hypothalamic neurohormone regulation and release of pituitary hormones.

Question 38

What is the neuroendocrine reflex?

Answer 38

stimulus --> nervous system --> triggers release of hormones

Question 39

What is reflex arc vs neuroendocrine reflex?

Answer 39

Nerodendocriene is where stimulus creates release of hormones whilst arc involves sensory and motor neurons to create muscle reflex

Question 40

Describe the secretion of GnRH into the portal system

Answer 40

pulsatile

Question 41

is CRH secerted in other parts of the nervous system?

Answer 41

Yes- as neurotransmitters

Question 42

The Superior hypophyseal artery forms...

Answer 42

primary capilary plexus in the median eminence

Question 43

Increased serumosmolarity...

Answer 43

increases ADH release

Question 44

What is the effect of TRH on prolactin secretion?

Answer 44

It is a stimulatory hormone for prolactin production

Question 45

what is the only catecholamine released into the median eminence?

Answer 45

Dopamine

Question 46

What hormone can inhibt TRH secreation?

Answer 46

Growth Hormone Inhibiting Hormone

Question 47

What does CRH (from the hypothalamus) stimulate to secrete ACTH?

Answer 47

corticotropes

Question 48

Does estrogen decrease the recetors of oxytosin?

Answer 48

No- it increases them as is synegtic

Question 49

Paraventricular and supraoptic nuclei of the hypothalamus produce large quantities of

Answer 49

Neurohormones

Question 50

What peptide (apart from OT and ADH) is released from the PPG?

Answer 50

Neurophysin

Question 51

What occurs in diabetes insidious?

Answer 51

body makes too much urine

Question 52

How are pituitary hormones transported down the neurons

Answer 52

axoplasmic flow

Question 53

what does adiophils secrete?

Answer 53

prolactin (lactotrophs) and GH (somatotrophs)

Question 54

What is the stimulus for ADH secretion?

Answer 54

increased osmatic plasma pressure and decreased blood/ECF volume

Question 55

What are the major actions of ADH?

Answer 55

vasoconstriction, increased water absorption and increased blood pressure

Question 56

What are the two receptors that ADH can bind to?

Answer 56

V1 and V2

Question 57

What pathway is stimulated when ADH uses V1 receptor?

Answer 57

Phosoplice C to produce calcium

Question 58

What pathway is stimulated when ADH uses V2 receptor?

Answer 58

cAMP- PKA

Question 59

What second messenger does Oxytocin use and why?

Answer 59

GPCR--> PLC --> IP3 --> Ca. Needs calcium to allow for the contractions of uterine smooth muscle and myoepithelial cells,