Test 6 Endo Hypothalamus Slides 47-101 Flashcards
What regulates the control of Hormone Secretion?
- Signal from Nervous System
- Chemical Changes in the Blood
- Other Hormones
The diminution or counteraction of an effect y its own influence on the process giving rise to it, describes what?
Negative Feedback
Strengthens or reinforces of an effect by its own influence on the process that gives rise to it, describes what?
Positive Feedback
What portion of the brain is inferior to the thalamus, not considered a separate organ, controls the ANS, and serves as a major link between the nervous system and endocrine system?
Hypothalamus
How many hormones are synthesized by the cells of the Hypothalamus?
9
What portion of the brain and what glands are together responsible for regulation of growth, development, metabolism, and homeostasis?
Hypothalamus-Pituitary Gland Complex
Name the hypothalamic neurosecretory cells responsible for the synthesis of hypothalamic hormones that will be transported to the Anterior Pituitary?
- Dorsal Medial Nucleus
- Ventral Medial Nucleus
- Infundibular Nucleus
What are the steps to prepare Hypothalamic hormones for transport whose target is the ANTERIOR pituitary? (Dorsal Medial, Ventral Medial, Infundibular Nuclei)
1) Packaged in secretory vesicles
2) Transported by axons to axon terminals near superior aspect of infundibulum
3) Nerve impulses stimulate hormone release from axon terminals via exocytosis from secretory vesicles
Hypothalamic hormones diffuse into the primary capillary plexus, which is supplied by what artery?
Superior Hypophyseal artery
How are hormones transported to the ANTERIOR Pituitary that are produced by the Dorsal Medial, Ventral Medial, Infundibular Nuclei of the Hypothalamus?
1) Transported by Hypophyseal portal veins to secondary capillary plexus of Hypophyseal portal system
2) Hormones diffuse into ANTERIOR Pituitary target cells where they exert their action
The secondary capillary plexus of the Hypophyseal portal system is adjacent to what?
Anterior Pituitary Gland
Name the hypothalamic neurosecretory cells (clusters of specialized neurons) responsible for the synthesis of hypothalamic hormones that will be transported to the POSTERIOR Pituitary?
Supraoptic Nucleus
Paraventricular Nucleus
How are hormones transported to the POSTERIOR Pituitary that are produced by the Supraoptic and Paraventricular Nuclei of the Hypothalamus?
1) Packaged in secretory vesicles
2) Transported by axon to axon terminals within the POSTERIOR Pituitary
3) Stored in POSTERIOR Pituitary, no synthesis of hormones in POSTERIOR Pituitary
Name the Hypothalamic RELEASING Hormones that stimulate release of ANTERIOR Pituitary hormones.
- Growth Hormone-Releasing Hormone (GHRH)
- Thyrotropin-Releasing Hormone (TRH)
- Corticotropin-Releasing Hormone (CRH)
- Gonadotropin-Releasing Hormone (GnRH)
- Prolactin-Releasing Hormone (PRH)
Name the Hypothalamic INHIBITING Hormones that Inhibit release of ANTERIOR Pituitary hormones.
- Growth Hormone-Inhibiting Hormone (GHIH)(AKA: Somatostatin)
- Prolactin-Inhibiting Hormone (PIH)(AKA: Dopamine)
Name the Hypothalamic Hormones synthesized in hypothalamus and stored in the POSTERIOR Pituitary.
- Anti-Diuretic Hormone (ADH/Vasopressin)
- Oxytocin
Which Hypothalamic Nuclei synthesizes Anti-Diuretic Hormone (ADH/Vasopressin)?
Supraoptic Nuclei
Which Hypothalamic Nuclei synthesizes Oxytocin?
Paraventricular Nuclei
What is the technical term for the Pituitary Gland?
Hypophysis
What Endocrine gland is a small, pea-shaped gland located within the sella turcica of the sphenoid bone?
Pituitary Gland (Hypophysis)
What connects the Pituitary Gland to the Hypothalamus?
Infundibulum
What are the two separate portions of the Pituitary Gland?
- Anterior Pituitary
- Posterior Pituitary
What is the technical name for the Anterior Pituitary (Comprises 75% of total weight)?
Adenohypophysis (Pars Distalis)
What is the technical name for the Posterior Pituitary?
Neurohypophysis (Pars Nervosa)
What is the Anterior Pituitary Gland composed of?
Pars Distalis
Pars Tuberalis
What type of tissue is the Pars Distalis (Largest Portion)?
Glandular Tissue
What covers the infundibulum (like a sheath)?
Pars Tuberalis
The anterior pituitary gland produces hormones from 5 specific cell types within it, what type of hormones are these?
Tropic Hormones
What is a Tropic Hormone?
Hormone that exerts its effect on another endocrine gland
Anterior Pituitary hormones after synthesis are passed into what so they can enter general circulation?
Secondary Capillary Plexus and then into the Anterior Hypophyseal Veins
What cells within the Anterior Pituitary secrete Human Growth Hormone (AKA Somatotropin)?
Somatotrophs
What is the name of the releasing/stimulating hormone and the Inhibiting/suppressing hormone that has an affect on Somatotropin (hGH)?
Releasing: Growth Hormone Releasing Hormone (GHRH)
Inhibit: Growth Hormone Inhibiting Hormone (GHIH) (somatostatin)
What cells within the Anterior Pituitary secrete Thyroid Stimulating Hormone (Thyrotropin)?
Thyrotrophs
What is the name of the releasing/stimulating hormone and the name of the Inhibiting/suppressing hormone that has an affect on Thyrotropin (TSH)?
Releasing: Thyroid Releasing Hormone (TRH)
Inhibiting: Growth Hormone Inhibiting Hormone (GHIH)
What cells within the Anterior Pituitary secrete Follicle Stimulating Hormone (FSH) and Luteinizing Hormone (LH)?
Gonadotrophs
What hormone stimulates the release of FSH and LH?
Gonadotrohpin Releasing Hormone
No inhibiting hormone
What cells within the Anterior Pituitary secrete Prolactin Hormone (PRL)?
Lactotrophs
What will stimulate and inhibit the hormone PRL?
Releasing: Prolactin Releasing Hormone
Inhibit: Prolactin Inhibiting Hormone (PIH) and Nitric Oxide
What cells in the Anterior Pituitary secrete Melanocyte Stimulating Hormone (MSH)(Melanotropins) and Adrenocorticotropin Hormone (ACTH)(Corticotropin)?
Corticotrophs
What will Stimulate the release of ACTH (Corticotropin)?
Corticotropin Releasing Hormone
No inhibiting hormone
What will stimulate the release and inhibit MSH (Melanotropins)?
Releasing: Corticotropin Releasing Hormone
Inhibiting: Prolactin Inhibiting Hormone (PIH)
Which hormone is the most abundant Anterior Pituitary Hormone and secreted in bursts every few hours, especially during sleep by somatotrophic cells (most abundant cell)?
Human Growth Hormone (hGH)
What is the main function of Human Growth Hormone (hGH)?
Promote synthesis and secretion of
Insulin-like Growth Factors (IGF, somatomedins),
(small protein hormone)
In response to hGH cells in what tissues synthesize and secrete Insulin-like Growth Factors (Somatomedins) and where does IGF hormone have action?
Tissues: Liver, Skeletal Muscle, Cartilage, Bone
Enters bloodstream via Liver or acts locally as Autocrines or paracrines
IGF (Insulin-like Growth Factor) have what affects?
-Increases Protein Synthesis: Increases uptake of AA
-Decrease Protein Catabolism: Decreases breakdown by limiting use of AA for ATP production
-Stimulates growth in childhood: esp. bone, muscle
-Adults: Promotes tissue maintenance, healing, repair
Maintain muscle mass and bone structure
-Enhances Lipolysis (Adipose Tissue): Increases release of FA for ATP production
-Influences Carbohydrate Metabolism: Decreases glucose uptake, leaves it in bloodstream for neurons. Stimulates Liver glycogenolysis if hypoglycemic
What is secreted when the body is hyperglycemic?
Insulin
What is secreted when the body is in a hypoglycemic state?
1) GHRH secretion stimulated (Hypothalamus)
GHIH secretion inhibited (Hypothalamus)
2) GHRH stimulates secretion of hGH from Anterior Pituitary
-Increased hGH results in increased IGF concentration
-IGF results in chain reaction of Glycogenolysis in Liver and other tissues and Carbohydrate metabolism
What is secreted when the body is in a hyperglycemic state?
1) GHIH secretion stimulated (Hypothalamus)
GHRH secretion inhibited (Hypothalamus)
2) GHIH results in decrease in hGH
Decreased hGH results in decrease IGF
-Decrease IGF results in the cells taking up more glucose from bloodstream
What factors stimulate hGH secretion (Control of hGH secretion)?
- Sympathetic nervous system stimulation (stress, strenuous exercise)
- Deep sleep (stage 3-4 of non-REM)
- Decreased FA and increased AA in plasma
- Influence of glucagon, estrogen, cortisol, and insulin
What factors inhibit hGH secretion (Control of hGH secretion)?
- Increased FA and decreased AA in plasma
- REM sleep
- Emotional deprivation
- Obesity
- Plasma T3 and T4 levels are low
- hGH (somatotropin) itself is Negative Feedback
- GHIH (somatostatin)
hGH hypersecretion in childhood stimulates chondrogenesis in epiphyseal plates resulting in very tall individual w/almost normal body proportions, the medical term for this is?
Giantism (Gigantism)
hGH hypersecretion in adulthood causes enlargement of internal organs, thickened skin, and bone thickening (Enlarged facial features, feet, and fingers), the medical term for this is?
Acromegaly
Persistent hyperglycemia due to over secretion of hGH resulting in what?
Diabetogenic effect of hGH
1) Continually secretion of insulin from Beta-cells in pancreas
- Can cause beta-cell burnout
- Decreasing or stopping insulin secretion
- Perpetuates the hyperglycemia state
2) Causes DIABETES MELLITUS
hGH hyposecretion in childhood, causes epiphyseal plates to close before normal height is attained and individual retains childlike features, the medical term for this is?
Dwarfism
Congenital Dwarfism is due to what?
Genetic IGF deficiency
As we age hGH secretion decreases which may result in what?
Muscle wasting and Fat deposition
What stimulates the secretion of Adrenocorticotropin Hormone (ACTH)(Corticotropin) from the Anterior Pituitary?
- Corticotropin-releasing hormone (CRH) from Hypothalamus
- Stress-related stimuli (Hypoglycemia, physical trauma)
- Interleukin-1 (IL-1): secreted by macrophages
What does ACTH (Corticotropin, AKA Adrenocorticotropin Hormone) control production of and from where?
Cortisol and other glucocorticoids by the cortex of Adrenal Glands
Glucocorticoids inhibit what and in-turn this inhibits what via negative feedback?
CRH (Corticotropin-Releasing Hormone)
Which decreased levels of CRH decreases ACTH via negative feedback
The secretion of Prolactin (PRL) from the Anterior Pituitary is controlled by?
- Prolactin-Releasing Hormone (PRH) from Hypothalamus
- Prolactin-Inhibiting Hormone (PIH) (AKA Dopamine) from Hypothalamus
Prolactin’s actions by itself is weak what hormones work synergistically to increase its actions?
Estrogen Progesterone Glucocorticoids hGH Thyroxine (T4) Insulin
What is the effect in pregnant women when prolactin is synergistically producing its action with one of the following hormones, Estrogen, Progesterone, Glucocorticoids, hGH, Thyroxine (T4), Insulin
Milk production
Ejection of milk is caused by which hormone and where does it secrete from?
Oxytocin from the Posterior Pituitary
What is a likely reason for breast tenderness during menstruation?
Low levels of Estrogen and Progesterone prior to menstruation inhibit PIH (dopamine) and stimulate Prolactin secretion
How are the female hormones affected during the rest of the female cycle?
Estrogen secretion increases and PIH (Dopamine) secretion increases which results in inhibiting prolactin secretion
What is a common cause of Prolactin Hypersecretion?
Prolacinoma (benign pituitary adenoma)
What patients should a diagnosis of Prolactinoma be considered?
- Non-pregnant, non-lactating female complaints of milky breast discharge
- Male w/ED w/no obvious cause (such as older, HTN, obese)
- Male w/milky breast discharge