Anatomy and Physiology 2 Chapter 18 - Endocrine System Hormones of the Hypothalamus and Pituitary Gland

what are 4 things that are important about the hypothalamus

1. acts as endocrine organ = link between endocrine and nervous system

2. secretes regulatory hormones

3. contains autonomic centers to exert direct neural control over adrenal medulla

4. negative feedback

2 things about the pituitary gland controlled by the hypothalamus

1. makes hormones of the posterior pituitary gland (hormones stored here)

2. releases regulatory factors to anterior pituitary gland

2 hormones associated with the neurohypophysis

1. oxytocin (OXT)

2. antidiuretic hormone (ADH)/vasopressin

neurohypophysis

the posterior lobe of the pituitary gland

3 things about the neurohypophysis

1. doesn’t make hormones, only stores them

2. contains axons of the hypothalamus

3. neurons from the supra-optic and paraventricular nuclei create: oxytocin and ADH/vasopressin

*both hormones stored in axons until they need to be released and go through capillaries to get to the bloodstream

oxytocin (OXT) - 3

1. stimulate uterine contractions during birth

2. stimulate nipples to eject milk

3. peak during orgasms in males and females

antidiuretic hormone (ADH)/vasopressin - 1

responds to osmoreceptors which measure the amount of solute concentration in the bloodstream = usually when high; triggers us to be thirsty and kidneys pull out more solute causing blood vessels to constrict

3 things about the hypophyseal portal system

1. hypothalamus releases regulating hormones into median eminence

2. enters bloodstream via network around infundibulum

3. moves through vessels to capillaries in anterior lobe of the pituitary gland

adenohypophysis

anterior lobe of the pituitary gland

3 parts of the adenohypophysis

1. pars tuberalis

2. pars intermedia

3. pars distalis

what hormones are produced by the pars tuberalis

no hormones are made here

what is the hormone made by the pars intermedia

melanocyte stimulating hormone (MSH)

melanocyte stimulating hormone (MSH)

1. stimuli:

   1. fetal development

   2. young children

   3. pregnant women

   4. disease

2. targets: melanocytes or cells that create melanin

3. effects: increase melanin production

4. inhibitor: dopamine

6 hormones of the pars distalis

1. growth hormone (GH)/somatotropin

2. prolactin (PRL)

3. adrenocorticotropic (ACTH)/corticotropin

4. follicle-stimulating hormone (FSH)

5. luteinizing hormone (LH)

6. thyroid stimulating hormone (TSH)/thyrotropin

growth hormone (GH)/somatotropin

1. stimuli: GH-RH (growth hormone-releasing hormone)

2. targets:

   1. liver: releases somatomedins which increase AA uptake

   2. skeletal and muscle cells very sensitive

   3. most all tissue respond

3. effects:

   1. direct:

      1. increase rate of protein synthesis

      2. breakdown triglycerides in adipose (glucose sparing effect)

      3. breakdown liver glycogen into glucose

   2. indirect:

      1. regulates growth and cell division

      2. stimulates stem cell division and differentiation

4. inhibitors: GH-IH (somastatin)

prolactin (PRL)

1. stimuli: PRH (prolactin releasing hormone)

2. targets:

   1. mammary glands

   2. interstitial endocrine glands

3. effects:

   1. breast development

   2. milk production

   3. regulates androgen production via LH sensitivity

4. inhibitors: PIH (dopamine) = NT

tropic hormones

hormones of the adenohypophysis that turn on endocrine glands or support the functions of other organs

adrenocorticotropic hormone (ACTH)/corticotropin

1. stimuli: CRH (corticotropic-releasing hormone)

2. targets: adrenal cortex to release glucocorticoids

3. effects: increase glucose metabolism for fight or flight response

4. inhibitors: glucocorticoids

follicle-stimulating hormone (FSH) - gonadotropin

1. stimuli: GnRH (gonadotropin-releasing hormone)

2. targets: gonads

3. effects:

   1. ovarian development

   2. with LH, allows estrogens to be secreted

   3. tell nurse cells to mature sperm

4. inhibitors: inhibin released by gonads (on FSH and maybe GnRH)

luteinizing hormone (LH) - gonadotropin

1. stimuli: GnRH (gonadotropin-releasing hormone)

2. targets: gonads

3. effects:

   1. release of reproductive cells (ovulation)

   2. promotes secretion of estrogen and progesterone

   3. release of androgen sex hormones by testes

4. inhibitors:

   1. estrogens

   2. progesterone

   3. androgens

thyroid stimulating hormone (TSH)/thyrotropin

1. stimuli: TRH (thyrotropin-releasing hormone)

2. targets: thyroid gland

3. effects:

   1. thyroid releases TH (T3 and T4)

   2. regulates growth, development, and metabolism

4. inhibitors:

   1. TH

   2. GH-IH