Endocrine System Flashcards
____-Ductless glands that secrete hormones
Endocrine gland
_____- chemical messages that travel through the blood to regulate target cells. Target cells must have specific receptors to which the hormone binds These receptors may be intracellular or located on the plasma membrane They trigger a change - the changes that occur in the cell after hormone binding is typically one or more of the following: o Alter plasma membrane permeability o Synthesis of proteins o Activate or inactivate enzymes o Stimulate cell division (mitosis)
Hormones
____- Secretes releasing hormones that control the activity of the anterior pituitary gland. Examples: thyrotropin releasing hormone (TRH), corticotropin releasing hormone (CRH), gonadotropin releasing hormone (GnRH), Produces ADH and oxytocin that are released from posterior pituitary gland Controls sympathetic output to the adrenal medulla
Hypothalamus
_____- hangs by a stalk from the inferior surface of the hypothalamus. It contains two functional lobes: anterior pituitary made of glandular tissue and the posterior pituitary made of nervous tissue.
Pituitary gland
Pituitary gland;
____-– nervous tissue o Hypothalamus is connected to the posterior pituitary by neural tissue o Nuclei of the hypothalamus synthesize hormones that are transported to the posterior pituitary where they are stored and released:
*Oxytocin
*Antidiuretic hormone (ADH)
Posterior pituitary gland (neurohypophysis)
Posterior pituitary gland (neurohypophysis):
______- causes uterine contractions during child birth and milk ejection reflex during nursing
Oxytocin
Posterior pituitary gland (neurohypophysis):
_____- stimulates reabsorption of water in the kidneys leading to reduced urine volume
Antidiuretic hormone (ADH)
______- glandular tissue Connected to the hypothalamus by the hypophyseal portal system – capillary beds
Anterior pituitary gland (adenohypophysis)
______-produced by the anterior pituitary to stimulate growth of another gland and regulate the release of hormones from other endocrine glands.
Tropic hormones
Tropic hormones: \_\_\_\_ hormone (TSH) – targets thyroid gland to produce hormones Release stimulated by the hormone TRH from the hypothalamus
Thyroid- stimulating hormone (TSH)
Tropic hormones
_______hormone (ACTH) – stimulates the adrenal cortex to release glucocorticoids Release stimulated by CRH from the hypothalamus
Adrenocorticotropic hormone (ACTH)
Tropic hormones \_\_\_\_\_\_\_\_\_\_\_\_\_ hormone (FSH)- Females - stimulates egg maturation and estrogen production, Males – stimulates sperm development Release stimulated by GnRH from the hypothalamus
Follicle- stimulating hormone (FSH)
Tropic hormones \_\_\_\_\_\_\_\_ hormone (LH)- Females – stimulates ovulation and progesterone production, Males – stimulates testes to produce testosterone Release stimulated by GnRH from the hypothalamus
Luteinizing hormone (LH)
Tropic hormones \_\_\_\_\_\_\_\_\_\_ hormone (GH) - stimulates cell growth and division in skeletal muscle and bone, stimulates the liver to produce insulin-like growth factor (IGF). Release stimulated by GHRH from the hypothalamus
Growth hormone (GH)
Tropic hormones
_________ (PRL) – stimulates growth of the mammary gland and milk production. Release stimulated by Estrogen from the ovaries
Prolactin (PRL)
_____-butterfly shaped gland located in the anterior cervical region. Thyroid hormones (T3 & T4)- Increases cell metabolism, o Important in normal tissue growth o Produced by follicular cells o Release stimulated by TSH from the anterior pituitary
Thyroid gland
______– Decreases blood calcium levels o Stimulates osteoblasts, inhibits osteoclast o Produced by C cells of the thyroid gland (a.k.a. parafollicular cells) o Release stimulated by high calcium levels (hypercalcemia)
Calcitonin
_________________ gland- tiny masses found on the posterior side of the thyroid
Parathyroid hormone (PTH) is secreted by chief cells (a.k.a principal cells) in response to low blood calcium levels (hypocalcemia).
Stimulates osteoclasts to release calcium from bone, stimulates activation of vitamin D leading to increased absorption of Ca2+ in digestive tract, stimulates reabsorption of calcium in the kidneys.
Parathyroid gland
_________________ glands - paired, pyramid-shaped organs atop the kidneys, Structurally and functionally, they are two glands in one (adrenal medulla and adrenal cortex)
Adrenal medulla – located in the center of the gland
o Nervous tissue that acts as part of the sympathetic nervous system
Adrenal glands
Adrenal gland
Produces 16)__________________________(adrenaline) and norepinephrine o Release stimulated by preganglionic sympathetic fibers
epinephrine
_____- glandular tissue, outer layer, synthesizes and releases steroid hormones
Adrenal cortex
Three zones of the adrenal cortex:
Zona glomerulosa
Zona fasciculata
Zona reticularis
What zone of the adrenal cortex is this?
____- superficial layer, deep to the capsule. Produces mineralocorticoids (chiefly aldosterone) – reabsorption of sodium, secretion of potassium.
Zona glomerulosa
What zone of the adrenal cortex is this?
_____-middle layer. Produces __________ (chiefly cortisol) long term stress response increases blood glucose levels by stimulating synthesis of glucose from protein, increases appetite, suppresses the immune system decreasing inflammation.
Release stimulated by ACTH from anterior pituitary
Zona fasciculata
*Glucocorticoid
______-deepest layer Produces gonadocorticoids including dehydroepiandrosterone (DHEA) an androgen (hormone that binds to the same receptor as testosterone) to stimulate maturation of hair follicles in women during puberty.
Zona reticularis
__________– organ located posterior to the stomach that functions as both an endocrine and exocrine gland
Pancreas
_________ cells – exocrine cells that produce digestive enzymes that are secreted into the duodenum
Acinar cells
Acinar cells:
The endocrine cells are organized into the islets of Langerhans: o Alpha (α) cells – produce the hormone __________- that triggers the breakdown of glycogen in the liver, thus increases blood glucose levels o Release stimulated by low blood glucose (hypoglycemia)
Glucagon
Acinar cells
- produce the hormone ______________- that increases the uptake of glucose into the cells, thus decreases blood glucose levels o Release stimulated by high blood glucose (hyperglycemia)
Insulin
_____- is found in the diencephalon of the brain produces the hormone Melatonin that regulates sleep / wake cycles Release stimulated by the hypothalamus during dark hours
Pineal gland
________ – located in the upper thoracic cavity over the heart produces the hormone Thymosin that regulates maturation of T-lymphocytes
Thymus
Gonads
In women are called the
________- located in the pelvic cavity produces the steroid sex hormones:
____ – stimulates secondary sex characteristics at puberty, plays role in regulating ovarian and uterine cycles
_______ – works with estrogen to maintain uterine cycle
Ovaries
- Estrogen
- Progesterone
Gonads:
In men are called the 25)___________________- located in the scrotum produces the steroid sex hormone ________ that stimulates spermatogenesis and secondary sex characteristics at puberty
Testes
*Testosterone
