Chapter 11:
➢ Describe the chemical nature of hormones and define the terms prehormone and prohormone
What gives hormones the chemical nature?
- A hormone is a chemical signal
- Hormones are secreted by a cell or group of cells
- Hormones are secreted into the blood
- secretion from a cell to ECF or external environment
- hormones are transported to a distant target
- transported by blood
- growth factors act at short distance
- Hormones exert their effect at very low concentrations
What is pre hormone?
- Inactive prohormones that must be modified within their target cells
What are prohormones?
- Inactive hormones that must be cut (and spliced) together to be active
➢ Describe the different types of hormone interactions and the significance of hormone concentrations
What are the hormone interactions?
- Synergistic effects: in which two hormones with similar effects produce an amplified response
- Permissive effects: in which the presence of one hormone enables another hormone to act
- Antagonistic effects: in which two hormones have opposing effects
Effects of hormone concentrations on tissue response:
- Hormone half-life
- Hormone concentration
- Priming effects/upregulation
- Desensitization and downregulation
➢ Distinguish between the anterior and posterior and identify the hormones secreted by each part
What is the difference/similarities between the anterior and posterior pituitary gland?
- They are two lobes of the pituitary gland
- Each lobe secretes hormones that regulates functions of the other endocrine glands such as adrenal gland,
thyroid gland, ovaries and testis
- The main difference between anterior and posterior pituitary gland is that the action of the anterior pituitary
gland is regulated through vessels connected to the hypothalamus whereas the action of the posterior
pituitary gland is regulated through nerves connected to the hypothalamus
What hormones are secreted by the anterior lobe?
- Growth hormone (GH)
- Thyroid-stimulating hormone (TSH) stimulates THYROXINE
- Adrenocorticotropic hormone (ACTH) - stimulates corticosteroids
- Follicle stimulating hormone (FSH)
- Luteinizing hormone (LH) - in the male, it is interstitial cell stimulating hormone (ICSH)
- Prolactin (PRL)
*CRH stimulates ACTH
, What hormones are secreted by the posterior lobe?
- Antidiuretic hormone (ADH)
- Oxytocin
➢ Explain how the hypothalamus regulates both the posterior and anterior pituitary glands
What are the regions of the hypothalamus and their function?
- Lateral region: hunger
- Medial region: satiety
- Preoptic-anterior: shivering, hyperventilation, vasodilation, sweating
- Supraoptic:produces antidiuretic hormone, which helps control urine formation
- Paraventricular: produces the hormone oxytocin which stimulates childbirth
How does the hypothalamus communicate with the posterior and anterior pituitary glands?
- Hormones secreted by the hypothalamus would be classified as paracrine
- Through that stalk, your hypothalamus communicates with the anterior pituitary lobe via hormones and the
posterior lobe through nerve impulses.
- ADH and oxytocin are transported along the hypothalamo-hypophyseal tract to the posterior pituitary
gland, where they are stored until needed
- The hypothalamus also produces releasing hormones and inhibiting hormones that are transported along the
adenohypophysis to the anterior pituitary gland to regulate the secretion of pituitary hormones
What is hypothalamic control/regulation of the anterior pituitary gland?
- Anterior pituitary is controlled via releasing and inhibiting hormones through the
hypothalamo-hypophyseal portal system
- Releasing and inhibiting hormones
What is true about hypothalamic releasing hormones?
- They are secreted into capillaries in the median eminence
- They are transported by portal veins to the anterior pituitary
- They stimulate the secretion of specific hormones from the anterior pituitary
What is the hypothalamic control/regulation of the posterior pituitary
- Adh and oxytocin are produced by the supraoptic and paraventricular nuclei of the hypothalamus,
respectively
- They are transported along axons of the hypothalamo-hypophyseal tract to the posterior pituitary where
they are stored
- Release is controlled by neuroendocrine reflexes
- ADH is stimulated by an increase in blood osmolality
- oxytocin is stimulated by sucklings
*One fact about posterior pituitary hormones that ISN’T true is they include direct and tropic hormones
➢ Describe negative feedback inhibition in the regulation of hypothalamic and anterior pituitary
hormones
What are the steps of the feedback control of anterior pituitary?
- The final product regulates secretion of pituitary hormones - negative feedback inhibition
- The relationship between the hypothalamus, anterior pituitary and the target tissue is called an axis
- Inhibition can occur at the pituitary gland level, inhibiting response to hypothalamic hormones
- Inhibition can occur at the hypothalamus level, inhibiting secretion of releasing hormones
➢ Identify the hormones of the adrenal medulla, as well as the categories of corticosteroid hormones
and their specific origin
Hormones of the adrenal medulla:
➢ Describe the chemical nature of hormones and define the terms prehormone and prohormone
What gives hormones the chemical nature?
- A hormone is a chemical signal
- Hormones are secreted by a cell or group of cells
- Hormones are secreted into the blood
- secretion from a cell to ECF or external environment
- hormones are transported to a distant target
- transported by blood
- growth factors act at short distance
- Hormones exert their effect at very low concentrations
What is pre hormone?
- Inactive prohormones that must be modified within their target cells
What are prohormones?
- Inactive hormones that must be cut (and spliced) together to be active
➢ Describe the different types of hormone interactions and the significance of hormone concentrations
What are the hormone interactions?
- Synergistic effects: in which two hormones with similar effects produce an amplified response
- Permissive effects: in which the presence of one hormone enables another hormone to act
- Antagonistic effects: in which two hormones have opposing effects
Effects of hormone concentrations on tissue response:
- Hormone half-life
- Hormone concentration
- Priming effects/upregulation
- Desensitization and downregulation
➢ Distinguish between the anterior and posterior and identify the hormones secreted by each part
What is the difference/similarities between the anterior and posterior pituitary gland?
- They are two lobes of the pituitary gland
- Each lobe secretes hormones that regulates functions of the other endocrine glands such as adrenal gland,
thyroid gland, ovaries and testis
- The main difference between anterior and posterior pituitary gland is that the action of the anterior pituitary
gland is regulated through vessels connected to the hypothalamus whereas the action of the posterior
pituitary gland is regulated through nerves connected to the hypothalamus
What hormones are secreted by the anterior lobe?
- Growth hormone (GH)
- Thyroid-stimulating hormone (TSH) stimulates THYROXINE
- Adrenocorticotropic hormone (ACTH) - stimulates corticosteroids
- Follicle stimulating hormone (FSH)
- Luteinizing hormone (LH) - in the male, it is interstitial cell stimulating hormone (ICSH)
- Prolactin (PRL)
*CRH stimulates ACTH
, What hormones are secreted by the posterior lobe?
- Antidiuretic hormone (ADH)
- Oxytocin
➢ Explain how the hypothalamus regulates both the posterior and anterior pituitary glands
What are the regions of the hypothalamus and their function?
- Lateral region: hunger
- Medial region: satiety
- Preoptic-anterior: shivering, hyperventilation, vasodilation, sweating
- Supraoptic:produces antidiuretic hormone, which helps control urine formation
- Paraventricular: produces the hormone oxytocin which stimulates childbirth
How does the hypothalamus communicate with the posterior and anterior pituitary glands?
- Hormones secreted by the hypothalamus would be classified as paracrine
- Through that stalk, your hypothalamus communicates with the anterior pituitary lobe via hormones and the
posterior lobe through nerve impulses.
- ADH and oxytocin are transported along the hypothalamo-hypophyseal tract to the posterior pituitary
gland, where they are stored until needed
- The hypothalamus also produces releasing hormones and inhibiting hormones that are transported along the
adenohypophysis to the anterior pituitary gland to regulate the secretion of pituitary hormones
What is hypothalamic control/regulation of the anterior pituitary gland?
- Anterior pituitary is controlled via releasing and inhibiting hormones through the
hypothalamo-hypophyseal portal system
- Releasing and inhibiting hormones
What is true about hypothalamic releasing hormones?
- They are secreted into capillaries in the median eminence
- They are transported by portal veins to the anterior pituitary
- They stimulate the secretion of specific hormones from the anterior pituitary
What is the hypothalamic control/regulation of the posterior pituitary
- Adh and oxytocin are produced by the supraoptic and paraventricular nuclei of the hypothalamus,
respectively
- They are transported along axons of the hypothalamo-hypophyseal tract to the posterior pituitary where
they are stored
- Release is controlled by neuroendocrine reflexes
- ADH is stimulated by an increase in blood osmolality
- oxytocin is stimulated by sucklings
*One fact about posterior pituitary hormones that ISN’T true is they include direct and tropic hormones
➢ Describe negative feedback inhibition in the regulation of hypothalamic and anterior pituitary
hormones
What are the steps of the feedback control of anterior pituitary?
- The final product regulates secretion of pituitary hormones - negative feedback inhibition
- The relationship between the hypothalamus, anterior pituitary and the target tissue is called an axis
- Inhibition can occur at the pituitary gland level, inhibiting response to hypothalamic hormones
- Inhibition can occur at the hypothalamus level, inhibiting secretion of releasing hormones
➢ Identify the hormones of the adrenal medulla, as well as the categories of corticosteroid hormones
and their specific origin
Hormones of the adrenal medulla:
