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
