Anterior Pituitary Gland Flashcards
Ant Pituitary 3 regions
- Pars distalis
- Pars tuberalis
- Pars intermedia
Which hormones are released by the anterior pituitary
- Growth Hormone (GH)
- Thyroid-stimulating hormone (TSH)
- Adrenocorticotropic hormone (ACTH)
- Prolactin (PRL)
- Luteinizing Hormone (LH)
- Follicle-Stimulating Hormone (FSH)
Regulation of Ant Pituitary secretions
- Hormones reach Ant Pituitary via hypophyseal portal system
- Essentially a shunt
- Takes venous blood carrying regulatory hormones from the hypothalamus directly to the ant pituitary
Hypophyseal Portal System
Median Eminence
- Swelling near attachment of infundibulum
- Whre hypothalmic neurons release regulatory factors
- Into interstitial fluids
- Through fenestrated capillaries
Hypothalmic control of ant pituitary
- 2 classes of regulatory hormone from hypothalamus
- Releasing hormone
- Stimulate synthesis and secretion of one or more hormones at anterior lobe
- Inhibiting hormone
- Prevent synthesis and secretion of hormones from the anterior lobe
- Releasing hormone
- Rate of secretion is controlled by negative feedback
FSH
Function
- Female: Act on the follicular cells in ovary to regulatematuration of follicular cells and oocytes, and production of estrogen
- Male: Act on cells of testes to regulate the maturation of the spermacytes
FSH
Deficiency and what can go wrong
- Irregular mestrual cycle, affected production of serm, infertility or impotence
- Creating a lack of ovulation in females and infertility in men
LH
Function
- Female: Act on the follicular cells in ovary for ovulation and productiopn of progesterone
- Male: Act on the interstitial cells of the testes to regulate the production of sprem
LH
Deficiency and what can go wrong
- Irregular menstural cycle, impotence
- Amenorrhoea and impotence
ACTH
Function
Deficiency
What can go wrong
- Acts on adrenal cortex to stimulate production and secretion of corticosteroid
- Stimulates conversion of cholesterol to pregnenolone (precursor of cortisol)
- Released from pituitary following a circadian rhythym peaking in the morning and then declining
- Defi- stressed out
- What can go wrong- Cushing syndrome- tissue exposed to cortisol for long periods of time
Cushings Signs and Symptoms
- Decreased immune response
- More prone to infection
- Decrease resistance to stress
- Death usually from infection
TSH
Function
Regulates release of thyroid hormones from the thyroid gland
Target:Thyroid
Thyroid releasing hormone from the hypothalamus can be affected by blood levels, glucose, and bodys metabolic rate
TSH
Deficiency
What can go wrong
D- metabolism, cardiovascular, GI tract, motor NS
Congenital problems–> affecting any of the pituitary horones, loss of midline structures like septo-optic dysplasia (loss of optic nerve)
Prolactin
- Mammary gland growth and milk production
- Influence sensitivity if interstitial cells to LH
Prolactin
Def and what can go wrong
- D- little to no milk production, fertility issues
- High levels lead to loss of reproductive function and inapproprite milk production
GH
Stimulates cell growth and division and liver production of somatomodin
Targets all cells
GHRH affected by stress, sleeping, exercise, blood glucose levels
