Ch 17-Endocrine
Describe the general structure, location, and function of the pineal gland
Pineal gland is a small, cone shaped structure forming the posterior region of the epithalamus. It's a crease melatonin, which makes us drowsy.
Describe the structure and location of the adrenal glands
The adrenal glands are anchored on the superior surface of each kidney and have both an outer cortex and an inner medulla. Each adrenal gland is a two-part gland that secretes stress-related hormones. The adrenal cortex produces corticosteroid hormones (e.g., cortisol), and the adrenal medulla produces epinephrine and norepinephrine.
Explain what is meant by the half-life of a hormone
The half-life is the amount of time necessary to reduce the hormone concentration within the blood to 1/2 of what had been secreted originally
Define up regulation and down regulation
Up regulation is a generation of more receptors, and down regulation is a decrease in the number of receptors
Describe how the hypothalamus controls the release of glucocorticoid (cortisol) and the effects of cortisol.
Upon receiving certain stimulation, the hypothalamus secretes CRH, which causes the release of a CTH from the anterior pituitary. This relationship is called the hypothalamus Dash pituitary - adrenal axis
Compare the transport of lipid soluble hormones with that of water soluble hormones
Water soluble hormones readily dissolved in the aqueous environment of the blood. Lipid soluble hormones must attach to a carrier protein molecule to be transported within the blood
Insulin is made up of a chain of amino acids. Is it water soluble or lipid soluble?
Water; because it is a protien
If hormone x and hormone y had the same rate of synthesis, but x's elimination rate was faster, which would be at a higher level in the blood?
Y
Where are secondary plexus blood vessels located
anterior pituitary
Identify the specific structures associated with the posterior pituitary and the anterior pituitary
- Posterior pituitary: 1/4 of mass of pituitary gland; nervous tissue - Anterior pituitary: 3/4 of mass of pituitary gland; endocrine
Compare and contrast the three types of hormone interactions
1. Synergistic: hormones work together to produce greater effect (e.g., estrogen and progesterone in female reproductive structures) 2. Permissive: first hormone allows action of second hormone (e.g., prolactin is required to produce breast milk, and oxytocin is required for milk ejection from the breast) 3. Antagonist: one hormone causes opposite effect of another (e.g., glucagon and insulin)
Name the three zones of the adrenal cortex and the hormones produced in each zone.
1. Zona glomerulosa: thin, outer layer composed of spherical cells that synthesize mineralocorticoids (e.g., aldosteroid regulates the ration of Na+ and K+ in our blood and body fluids by altering the amounts excreted by the kidney into the urine), a group of hormones that help regulate the composition and concentration of electrolytes in body fluids. 2. Zona fasciculata: the middle layer and largest region of the adrenal cortex. The primary glucocorticoids synthesized in this region are cortisol and corticosterone. 3. Zona reticularis: the innermost region of the cortex with cells capable of secreting minor amounts of sex hormones called gonadocorticoids (e.g., androgens).
Describe the general function of local hormones
A large group of signaling molecules that do not circulate within the blood.
What is the primary mineralocorticoid and what are its specific affects
Aldosterone-regulates blood sodium and potassium levels by decreasing the sodium and increasing the potassium excreted in urine
Compare autocrine and paracrine signaling that occurs through local hormones
Autocrine signaling stimulates the same cell that the hormone was released from. Paracrine signaling stimulates neighboring cells.
Describe the conditions that influence the number of receptors available for a specific hormone
Cells alter the number of receptors available and responsive to changes in hormone concentration within the blood changes in receptor number also occur as a consequence of developmental maturity, the cell state of activity, and the different stages of the cell.
Compare and contrast the actions of the endocrine system and the nervous system to control body function
Compare-specialize cells of both systems release chemical substances called ligands to communicate with particular target cells. The ligand binds to a cellular receptor in target cells to initiate cellular change. Contrast-The nervous system exercise control between two specific locations by way of neurons. The endocrine system exercises control between two specific locations in the body through secretion of hormones.
Explain the control of thyroid hormone by the hypothalamus and pituitary
Decreased levels of thyroid hormone and certain stimuli cause the hypothalamus to secrete thyrotropin-releasing hormone (TRH), which causes release of thyroid-stimulating hormone (TSH) from the anterior pituitary. TSH reaches the thyroid gland and causes release of thyroid hormone (TH) from a stored precursor. This interactive sequence is referred to as the hypothalamic-pituitary-thyroid axis. Thyroid hormone increases metabolism with a subsequent increase in body temperature. To support the higher metabolic rate additional glucose and fatty acids are released into the blood, heart rate and force of contraction are increased, and breathing rate is increased.
What effect would a decrease in insulin levels be expected to have on blood sugar
Elevated blood sugar
Identify the major endocrine glands as well as the organs that contain endocrine cells, and their location within the body
Endocrine organs include pituitary gland, pineal gland, thyroid gland, parathyroid glands, and adrenal glands. Organs that contain endocrine cells include hypothalamus, skin, thymus, heart, liver, stomach, pancreas, kidneys, and gonads.
Explain how the hypothalamus controls the release of hormones from the anterior pituitary and the general function of each
Hormonal stimulation triggers the release of hormones from the anterior pituitary.
Explain the three reflex mechanisms for regulating secretion of hormones
Hormonal stimulation-release of a hormone in response to another hormone humeral stimulation-release of hormones in response to changes in levels of nutrients in the blood nervous system stimulation-release of the hormone in response to stimulation by the nervous system
Describe how lipid soluble hormones reach their target cell receptors and the type of cellular change the initiate
Hormones that are lipid soluble stimulate cellular activity by binding to intracellular receptors: the hormone receptor complex activates a region of DNA resulting in the production of new proteins.
Describe how water soluble hormones and do cellular changing their target sells
Hormones that are water soluble bind with plasma membrane receptors; the hormone is the first messenger, and it causes the activation of G protein in the formation of a second messenger
Parathyroid hormone is secreted when blood calcium levels dropped to low. What sort of stimulation is this?
Humeral stimulation
Distinguish the hormones that are lipids soluble from those that are water soluble
Lipid soluble-steroids, calcitriol Water soluble-proteins, biogenic amines
How is it that changes in the levels of fatty acids in the blood can affect blood sugar levels
Lipogenesis
At what time of day or growth hormone levels highest
Nightly hours
Is the entire pancreas an endocrine organ?
No, it is also digestive
Where is oxytocin synthesized and where is it released
Oxytocin is released from the posterior pituitary
What effect does PTH have on blood calcium levels
PTH functions to increase blood calcium levels. It stimulates release of calcium from bone tissue, decreases loss of calcium in urine, and causes the kidneys to release an enzyme
What function is served by the pancreatic islet
Pancreatic islet cell is composed of two primary types of cells: alpha cells that secrete glucagon, and beta cells that secrete insulin.
Describe the general characteristics of the endocrine system
Regulates and controls many metabolic processes, helps maintain body homeostasis, serves as one of the two major control systems of the body
Describe the homeostatic system involving growth hormone.
Release of GH from the anterior pituitary is controlled by the release of growth hormone-releasing hormone (GHRH) and growth hormone-inhibiting hormone (GHIH) from the hypothalamus. Growth hormone stimulates the release of insulin-like growth factor (IGF) (somatomedin) from the liver; both GH and IGF stimulate target cells (especially muscle) to increase protein synthesis, mitosis, and cell differentiation; liver to increase both glycogenolysis and gluconeogenesis; and adipose connective tissue to increase lipolysis.
List the hormones released from the hypothalamus that control the anterior pituitary
Releasing hormones (e.g., TRH, PRH, GnRH, CRH, GHRH) stimulate the release of hormones from the anterior pituitary, and inhibiting hormones (e.g., PIH, GIH) decrease the release of hormones from the anterior pituitary.
Identify the primary types of pancreatic islet cells in the hormones they produce
Scattered among the pancreatic acini are small clusters of endocrine cells called pancreatic islets. A pancreatic islet cell is composed of two primary types of cells: alpha cells that secrete glucagon, and beta cells that secrete insulin.
Which type of hormone generally has a protein carrier in the blood,?
Steroid hormone
Describe the gross anatomy and cellular structure of the pancreas
The pancreas situated between he duodenum of the small intestine and the spleen and directly posterior to the stomach. It performs both exocrine and endocrine activities; thus, it is considered a heterocrine, or mixed, gland. The pancreas is mostly composed of groups of cells called pancreatic acini. Acinar cels are involved in exocrine activities and produce an alkaline pancreatic secretion (juice) that is secreted through pancreatic ducts into the small intestine. The pancreatic juice aids digestion.
What gland secretes melatonin and what is its affect
The pineal gland
Describe the anatomic relationship of the hypothalamus and pituitary gland
The pituitary gland is inferior to the hypothalamus and connected to it by the infundibulum. The hypothalamus communicates with the posterior pituitary via the hypothalamo-hypophyseal tract, which contains axons from two nuclei in the hypothalamus: the supraoptic nucleus and the paraventricular nucleus. The hypothalamus communicates with the anterior pituitary via the hypothalamo-hypophsyeal portal system, a vessel network that transports hormones from the hypothalamus to the anterior pituitary.
Explain the action of glucagon and raising blood glucose concentration
The release of glucagon from alpha cells results in an increase in glucose, glycerol, and fatty acids in the blood; it has no effect on structural and functional protein components of the body.
Describe the action of insulin and lowering blood glucose concentration
The release of insulin into the blood from beta cells results in a decrease in all nutrients in the blood (including glucose) and an increase in the storage of these molecules within body tissues.
Describe the general structure, location, and function of the parathyroid glands
The small, brownish red parathyroid glands are located on the posterior surface of the thyroid gland. They are usually for small nodules, and they have two different types of cells in them: chief cells and oxyphil
Describe the thyroid gland location and anatomy
The thyroid gland is a butterfly-shaped gland anterior to the trachea and inferior to the larynx.
Describe the two primary factors that affect the concentration level of a circulating hormones
The two primary factors that influence hormone concentration or hormone synthesis by endocrine glands and hormone elimination by the liver kidneys and target cells
Distinguish between the two types of organization of endocrine cells
They are organized either as a single organ with only an endocrine function or a cells house and small clusters within organs or tissues that have some other primary function
Identify the two hormones released from the posterior pituitary, and describe how the hypothalamus controls their release
oxytocin (OT), and antidiuretic hormone (ADH) both hormones are synthesized in the hypothalamus: The paraventricular nucleus primarily produces oxytocin, and the supraoptic nucleus primarily forms ADH upon stimulation, the nerve endings located in the posterior pituitary release ADH and OT; the posterior pituitary does not produce hormones but only stores and releases them
