Pituitary

Front 1

Hypothalamus

Back 1

• Region of lower brain, base of the diencephalon
• Integrates nervous and endocrine systems

Front 2

Inputs to hypothalamus from CNS

Back 2

Solitary
tract
–baroreceptors; olphactory
Locus coeruleus; Stress;
Ventrolateral medulla ­Stress

Front 3

hypothalamus
and
pituitary

Back 3

Front 4

The hypothalamic-­‐hypohyseal portal system

Back 4

• Directs trophic hormone delivery to the anterior pituitary
- only need a small amount of trophic hormones to get a big effect
- blood flow here is slow thus small amount persists for a long time and not much is needed

Front 5

Anterior Pituitary Hormones

Back 5

Front 6

Growth
hormone

Back 6

Front 7

GH pathway

Back 7

Front 8

acromegaly

Back 8

Front 9

GnRH Pathway

Back 9

Front 10

Prolactin Pathway

Back 10

Oestrogen increases number of prolacJn secreJng cells during pregnancy (BUT THEY ARE STILL NOT SECRETING PRL AT THIS POINT)
PIH suppresses ProlacJn release.
PIH falls towards end of pregnancy, prolacJn rises Following birth oestrogen and progesterone levels fall, suckling sJmulates prolacJn release and secreJon of
milk (LOSE THE PLACENTA THUS NO MORE INHIBITION BY E AND PG ANYMORE)

Front 11

the only 2 hormones that also have inhibitory hormones from the hypothalamus

Back 11

1. Prolactin
2. GH

Front 12

What else does prolactin suppress?

Back 12

- SUPPRESSES GnRH
- nursing one child u dont want more children
- thus some cultures have a child at the breast for 5years to avoid fertility

Front 13

HyperprolacJnaemia

Back 13

•ProlacJnoma
•Galactorrhea
•Functional gonadotrophin deficiency
Women = menstrual disturbance, infertility
Men = erectile dysfunction, diminished libido

Front 14

Endocrine regulation of reproductive physiology

Back 14

Front 15

Endocrine regulation of male reproductive physiology

Back 15

Front 16

External Influences on GnRH

Back 16

1. daily rhythms (peaks at midnight and 6am); night time penile eminence, wake up with an erection
2. annual rhythms: greater in winter, in the short day periods (EXPERIMENT WITH BEARD HAIR AND WRIGHT IN WINTER vs SUMMER)

- PULSTILE RELEASE IS V>IMPORTNAT (experiment where they used high levels and nothing happenedn until they used it pulsitilty

Front 17

LH has a direct negative feedback on GnRH

Back 17

True

Front 18

Menstrual Cycle

Back 18

Front 19

Early Follicular phase

Back 19

- recuirt many follicles and then the dominant follicle takes over and the rest die (atresia)
- autocrine manner INC. # of granulosa cells
- so high E with low FSH and LH due to negative feedback

Front 20

Late follicular phase/ovulaJon

Back 20

marked sens. of hypothalamus to E, desensitised and now the E is a +ve feedback and so u get a surge of GnRH and so get a peak in LH
- LH drives ovulation i.e occyte realease, then picked up in the infundibulum

Front 21

Luteal Phase

Back 21

suppression now with levels even lower than those in the normal early follicular phase

Front 22

Late Luteal phase/menses

Back 22

Front 23

Oxytocin
and
vasopressin (aka ADH)

Back 23

nonapeptides; varying by just one a.a
- both are synthesised as prohormones

Front 24

Oxytocin Protein Structure

Back 24

Front 25

Neurohypophysisis

Back 25

Front 26

Oxytocin and parturition

Back 26

plasma oxytocin in the mother during labour
- most powerful contraction agent

- also useful for placental ejection and stopping the bleeding

-stimulates partuition
- once the babies head stimulates the cervix and the process starts over

Front 27

Oxytocin and parturition pathway

Back 27

Front 28

Clinical Implications of Oxytocin during pregnancy

Back 28

- Syntocinon: used to induce labour and eject placenta
- Atosiban: OTA prevents premature birth

Front 29

Oxytocin and lactation – let­‐down reflex.

Back 29

Front 30

Myoepithelial cells

Back 30

contractile and express oxytoxin receptor
- mammary lobule

Front 31

Oxytocin During Suckling

Back 31

In-vivo bursts of supraoptic oxytocin neurons during suckling
- everytime the baby suckles, the release of oxytocin is immediate

Front 32

Non-­‐classical ac;ons of oxytocin

Back 32

- sexual arousal; the hormone of love (plays a major role in love in mena nd women but in men it also plays a major role in ejaculation). ALSO important for maternal bonding
- social dysfunction- Autism spectrum disorder (inability to respond to facial expressions and visual cues)
- Schizophrenia
- CV function: dec. BP

Front 33

Water reabsorption in Kidney tubules

Back 33

Front 34

Vasopressin (ADH)

Back 34

- more aquaporin-2 in the apical surface of the ducts

Front 35

Control of vasopressin secretion

Back 35

1. PLASMA OSMOLARITY: main driving force
2. Blood volume
3. BP

Front 36

Clinical Implication of Vasopressin control

Back 36

Bedwetting: (vasopressin nasal spray
– desucopressin

vasopressin is slighty higher during the night and it develops in children
- diurnial rhythm of vasopressin

can be used at night to avoid bed wetting (managed quite effectively)

Front 37

Vasopressin and Ang II link

Back 37

Front 38

Atrial Natriueritic Peptide

Back 38

Front 39

Vaasopressin in Hypovolemic Shock

Back 39

- INC. vascular resistance
- restores BP