Endocrine system pt 2 Flashcards
Concentrations of circulating hormone reflect:
- Rate of release
- Speed of inactivation and removal from the body
Hormones are removed from the blood by:
- Degrading enzymes => in blood/plasma
- The kidneys => to the urine
- Liver enzyme systems
What controlled by negative feedback systems and Vary only within a narrow desirable range
The Blood levels of hormones
Hormones are synthesized and released in response
to
(HNH)
- Humoral stimuli – blood level of ions like Ca++,sodium,
glucose, insulin - Neural stimuli – directly by nerve fibers
–epinephrine/norepinephrine (remember flight or fight?) - Hormonal stimuli – by other hormones (hypothalamus
hormones regulate anterior pituitary) FSH and LH levels
________? Provides highest level of endocrine function by integrating nervous and endocrine systems
hypothalamus
Synthesized by the supraoptic nuclei
Antidiuretic hormone (ADH)
Synthesized by the paraventricular nuclei
Oxytocin (OXT)
Secretes _______ that control anterior pituitary gland endocrine cells
regulatory hormones
_______: follicle-stimulating hormone (FSH) and luteinizing
hormone (LH)
* Regulate the function of the ovaries and testes
Gonadotropins
_____– promote estrogen/progesterone production
impacting uterus, testosterone production impacting male characteristics
LH ACCESSORY function
- Absent from the blood in prepubertal boys and girls
- Triggered by the hypothalamic gonadotropin-releasing hormone (GnRH)
during and after puberty
Gonadotropins
LH works with FSH to cause
maturation of the ovarian
follicle
Gonadotropins
* In females
LH works alone to trigger.
ovulation (expulsion of the
egg from the follicle)
Gonadotropins
* In females
LH promotes synthesis and
release of estrogens and
progesterone
Gonadotropins
* In females
LH stimulates interstitial
cells of the testes to produce
testosterone
Functions of Gonadotropins
* In males
LH is also referred to as
interstitial cell-stimulating
hormone (ICSH)
Functions of Gonadotropins
* In males
Receives, stores, and releases hormones from the hypothalamus
Neurohypophysis – posterior lobe (neural tissue) and
the infundibulum
_____: two-lobed organ that secretes nine
major hormones
Pituitary gland
Synthesizes and secretes a number of hormones
Adenohypophysis – anterior lobe, made up of glandular tissue
Triggered by hypothalamic peptide
thyrotropin-releasing hormone (TRH)
Thyroid Stimulating Hormone
Stimulates the normal development and
secretory activity of the _____
Thyroid Stimulating Hormone
Rising blood levels of thyroid hormones
act on the pituitary and hypothalamus to
block the release of TSH
Thyroid Stimulating Hormone
Stimulates the adrenal cortex to release corticosteroids (cortisol,
aldosterone)
Adrenocorticotropic Hormone
(Corticotropin)
Triggered by hypothalamic corticotropin-releasing hormone (CRH) in
a daily rhythm
Adrenocorticotropic Hormone
(Corticotropin)
“Corti” sugar releasing hormones and aldosterone (salt hormone)
Adrenocorticotropic Hormone
(Corticotropin)
GH is usually caused
by anterior pituitary tumor
* In children results in gigantism
* Can reach heights of 8 feet
* In adults results in acromegaly
* Overgrowth of hands, feet, and
face
Hypersecretion
GH
* In children results in pituitary
dwarfism
* May reach height of only 4 feet
* In adults usually causes no problems
Hyposecretion
- In females, stimulates milk production by the breasts
- Triggered by the hypothalamic prolactin-releasing hormone (PRH)
Prolactin (PRL)
- Inhibited by prolactin-inhibiting hormone (PIH)
- Blood levels rise toward the end of pregnancy
- Suckling stimulates PRH release and encourages continued milk
production
Prolactin (PRL)
- Posterior pituitary – made of axons of hypothalamic neurons, stores antidiuretic
hormone (ADH) and oxytocin - ADH and oxytocin are synthesized in the hypothalamus
- ADH influences water balance
The Posterior Pituitary Hormones
____ is a strong stimulant of
uterine contraction – also have
synthetic version to induce labor
Oxytocin
Regulated by a positive feedback
mechanism to ____ in the blood -
increased intensity of uterine
contractions, ending in birth
Oxytocin
helps to avoid dehydration or water overload
* Prevents urine formation => helps retain body water because
Greek diourein “to urinate,“
* Osmoreceptors monitor the solute concentration of the
blood
Antidiuretic Hormone (ADH)
Not enough ADH due to damage to hypothalamus or posterior
pituitary
Diabetes insipidus
What are the two forms of Thyroid Hormone TH
- T4 (thyroxine): major form that
consists of two tyrosine
molecules with four bound
iodine atoms - T3 (triiodothyronine): form that
has two tyrosines with three
bound iodine atoms
produced by the parafollicular, or C, cells of the thyroid
gland
A peptide hormone
made in thyroid
Calcitonin
is an autoimmune disease that
attacks the thyroid gland and causes hypothyroidism. Goiter is also present in this
disease
Hashimoto’s
TH in adults can lead to myxedema
Symptoms include low metabolic rate, thick and/or dry
skin, puffy eyes, feeling chilled, constipation, edema,
mental sluggishness, lethargy
Hyposecretion
most common
type is Graves’ disease
Hypersecretion of TH
_____ body makes
abnormal antibodies directed
against thyroid follicular cells
Autoimmune disease
- Tiny glands embedded in the
posterior aspect of the thyroid - Cells are arranged in cords
containing oxyphil and chief cells
Parathyroid Glands
