Ch 16 notes Flashcards by Hannah Hausmann

regulatory system is an

organ system that affects cells of other systems.

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One regulatory system is the X, which uses cells, called neurons, to send electrical signals, called impulses, to target cells.

nervous system

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X cause the neuron to release a chemical, called a neurotransmitter, which affects the target cell.

Impulses

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The extent to which the nervous system affects a target depends on X to it in a given amount of time.

the number of impulses sent

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Target’s X for the hormone; that is, how strongly the hormone attaches to the target (affects cell response

affinity

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Amino acid-based hormones include two major groups: X and X

biogenic amines and peptide hormones.

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Peptide hormones consist of X. Most X in the body fall into this group.

chains of amino acids, hormones, TSH, FSH,

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Eicosanoids are relatively small molecules derived from X with a X at one end.

arachidonic acid, a 20-carbon fatty acid (eicos, twenty), 5-carbon ring

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Steroid hormones are lipids derived from X and include three major groups: X

cholesterol, sex hormones, corticosteroids s, and calcitriol the active form of vitamin D,

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Hydrophilic hormones
Most are X-based

amino acid

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clearance time, which is the time it

remains in the blood.

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Transport proteins offer some degree of protection to lipid soluble hormones, allowing them to X). Unbound water-soluble hormones are more susceptible to hydrolytic enzymes and removal by the kidneys, thus X their clearance time.

remain longer in the blood (i.e., giving them a longer clearance time, reducing

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latency period (“hidden”) is the time required for tX. Lipid- soluble hormones have a relatively long latency period because they must bind to intracellular receptors. This binding usually initiates gene transcription in the nucleus to produce RNA molecules and requires additional time for RNAs to move to the cytoplasm where they participate in protein synthesis. However, the newly formed proteins will function for a reasonably long time, which accounts for the effects of lipid-soluble hormones being relatively long lasting. Think about how long it might take to receive a new car if you place an order for one with a number of specific requirements. While you will have to wait to get the car, its new condition will likely give you many years of service.

he hormone to have an effect after its introduction into the blood

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Since water-soluble hormones cannot diffuse through the X of endothelial cells that line the inside of capillaries, they must exit the capillaries through tiny “X. After leaving the capillary, they bind to X. (plasma membrane). Lipid-soluble hormones can easily X plasma membranes, then they bind to X receptors.

phospholipid membranes, pores, membrane-bound receptors on the target cell’s surface, pass through, intracellular

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Synergistic hormones cause X effects.

similar

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In some cases, a target cell’s response to a particular hormone may depend on its X to a different hormone. When this happens, the first hormone is said to have a X effect on the second hormone. the first hormone permits the target cell to respond to a second hormone X than it would have responded without exposure to the first hormone

previous exposure, permissive, more extensively

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The binding of a water soluble hormone causes the receptor to activate a X, located adjacent to the receptor in the plasma membrane. In response, it either activates or deactivates a X, causing the formation or release of a chemical referred to as a X in the cytoplasm. , in turn, causes an effect within the target cell, and this effect is attributed to the hormone. Two important substances that function as second messengers are cAMP and Ca2+ ions

G protein, membrane-bound enzyme, second messenger.

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In a few cases, the hormone acts as a ligand and when it binds, the channel X and allows specific X

opens, ions to diffuse through the plasma membrane.

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Most water-soluble hormones you will study this semester affect their target cells by affecting the amount of X present in the cytoplasm. Can be X or X

cAMP, excitatory, inhibitory

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Some hormones increase the activity of target cells by increasing the concentration of X ions inside those cells. This can be done by opening X located in the plasma membrane or membrane of the smooth endoplasmic reticulum.

Ca2+, Ca2+ channels

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Do lipophilic hormones go into the cell? What do they do and how

yes, The hormone receptor complex then interacts directly with the cell’s DNA, affecting transcription

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Humoral stimuli are

non-hormone substances in the bloodstream, and may include glucose, ions, etc.

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Neural stimuli involve

neurotransmitters released from axon terminals of postganglionic neurons in the autonomic nervous system.

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Hormonal stimuli are

hormones released from other endocrine glands.

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pituitary gland, also called the

hypophysis,

The anterior pituitary, or adenohypophysis (adeno, gland) comprises the anterior two-thirds of the pituitary gland and receives

hormonal stimuli from the hypothalamus.

Human growth hormone (hGH; also called

somatotropin)

What does HGH do?

Binds to most cells (except chondrocytes (cartilage cells) and osteoblasts (bone cells), induces growth/replication

However, hGH affects these cells indirectly through polypeptides called somatomedins or insulin-like growth factors (IGFs). The hGH causes X to release the X, which after reaching cartilage and osseous tissues stimulate chondrocytes and osteoblasts to grow and divide. In this way, hGH stimulates the growth in the skeletal system.

iver cells, skeletal myofibers, and a few other tissues, IGFs

More specifically, hGH causes cells to conserve X and X. It decreases protein X and increases protein X and the rate at which cells remove amino acids from the blood. It also decreases glucose X and promotes X.

proteins and carbohydrates, catabolism, synthesis, catabolism, glycogenesis

The stimulus for the release of hGH is

growth hormone-releasing hormone (GHRH) from the hypothalamus.

Conditions that cause the secretion of GHRH include X levels of glucose and fatty acids in the blood brought about by X

low, starvation, fasting, and exercise

In contrast, the hypothalamus inhibits the anterior pituitary with a hormone called X or X. Factors that promote somatostatin secretion include high levels of glucose, fatty acids, and hGH in the blood, and emotional stress.

growth hormone-inhibiting hormone (GHIH), somatostatin (statin, stand still)

Thyroid-stimulating hormone (TSH, also called thyrotropin) stimulates the thyroid gland to release X, which increases cX throughout the body.

thyroid hormone (TH), ellular metabolism and heat production

The stimulus for the release of TSH is

thyrotropin-releasing hormone (TRH) from the hypothalamus.

Factors that increase the secretion of TRH include .

exposure to cold temperature, low metabolic rate, pregnancy, and low levels of thyroxine in the blood

XAdrenocorticotropic hormone (ACTH), also called corticotropin, stimulates the X to secrete X, which increase blood glucose levels. The stimulus for the release of ACTH is corticotropin-releasing hormone (CRH) from the hypothalamus. Factors that increase CRH secretion include low levels of glucocorticoids or glucose in the blood and elevated body temperature.

adrenal cortex, steroids called glucocorticoids

Gonadotropins include X (Figure 16-5). X stimulates the gonads (ovaries and testes) to make gametes (sex cells), while X stimulates them to secrete hormones. In males, LH is called interstitial cell-stimulating hormone (ICSH), named for the interstitial cells that secrete it. The stimulus for the release of gonadotropins is gonadotropin-releasing hormone (GnRH) from the hypothalamus. In males, excess gamete production causes certain cells to secrete the hormone inhibin, which inhibits the release of GnRH.

follicle-stimulating hormone (FSH) and luteinizing hormone (LH), FSH, LH

Prolactin (prō-LAK-tin; PRL or lactogenic hormone) stimulates X to produce X (lact, milk). The stimulus for the release of PRL is X from the X.

mammary glands to produce milk, estrogen causing the release of prolactin-releasing hormone (PRH) from the hypothalamus. Inhibiting hormone is released from hypothalamus

The posterior pituitary, or X, comprises the posterior one-third of the pituitary gland and is not a true gland because it does not make X. Instead, the posterior pituitary contains X of neurons extending from the hypothalamus, and these terminals release X into the blood.

neurohypophysis, hormones, axon terminals, hormones

In a manner of speaking, the neurohypophysis functions as an X of the hypothalamus. The posterior pituitary releases two hormones, X both of which are amino acid-based and water-soluble.

extension, antidiuretic hormone and oxytocin,

Antidiuretic hormone (ADH) causes the kidneys to excrete less X (anti, against; uretic, urine) (Figure 16-6). Stimuli for the release of ADH include X.

urine, high blood osmotic pressure, low blood pressure, pain, and nicotine

Oxytocin (OT; “swift birth”) causes contraction of X. In the breasts, contraction of mammary gland ducts causes the secretion of X for the nursing infant. This hormone is described further in Chapter 23.

smooth muscle tissue in the uterus and breasts, milk

Thyroxine, also called thyroid hormone (TH), exists in two forms: T3, which is the active form, and T4, the inactive form. The thyroid gland synthesizes mostly T4, most of which is later converted to T3 in the liver and kidneys. T3, which we will refer to as TH, increases the metabolic activity of most cells in the body (Figure 16-7). Although it is amino acid-based, TH is lipid-soluble and travels through the blood bound to a transport protein. At target cells, TH binds to intranuclear receptors and increases the rate of RNA synthesis (transcription). TH also binds to receptors inside mitochondria where it increases the rate of cellular respiration. TH is the primary regulator of a person’s basal metabolic rate (BMR), or rate at which the body expends energy at rest. Since heat production correlates positively with the rate of cellular respiration, TH is important in maintaining body temperature by having a heat promoting (calorigenic) effect in the body (calor, heat).

H is synergistic with hGH in promoting protein synthesis and normal tissue development. The hormonal stimulus for TH release is TSH from the anterior pituitary, and the anterior pituitary releases TSH in response to TRH from the hypothalamus (discussed earlier). Iodine is an essential element for the production of TH, and a lack of iodine results in less TH synthesis. Lower TH levels in the blood cause the hypothalamus to release more TRH, which makes the pituitary release more TSH. Calcitonin (CT) is an amino acid-based, water-soluble hormone that decreases the blood’s Ca2+ ion concentration by stimulating osteoblasts to deposit osteoid. The osteoid then precipitates Ca2+ ions in the process of bone mineralization. As more Ca2+ ions enter the osteoid, more leave the blood. CT also inhibits osteoclasts, preventing them from dissolving bone, which would increase Ca2+ in the blood. Blood Ca2+ has a positive effect on CT secretion; thus, Ca2+ ions function as a humoral stimulus of the thyroid gland. The higher the blood’s Ca2+ concentration, the more CT is secreted. You can review the regulation of CT in Chapter 8 (Bone Physiology).

he parathyroid glands secrete X, =e that helps maintain optimum blood X levels in the blood.

parathormone (PTH), Ca2+

The adrenal cortex secretes a group of steroid hormones called corticosteroids, a name that denotes the source and chemical makeup of the secreted hormones. All corticosteroids are lipid-soluble and diffuse into target cells where they bind to intracellular receptors

Most cells in the adrenal cortex respond to stimulation from X from the anterior pituitary

adrenocorticotropic hormone (ACTH)

Mineralocorticoids are so named because they maintain concentrations of certain X in the blood.

minerals, including Na+, Cl–, and K+,

One major mineralocorticoid is X, which in target cells stimulates the formation of an enzyme required for the formation of X pumps

aldosterone,sodium-potassium

Aldosterone helps increase blood pressure by promoting X in the body. Retaining X increases the X of the blood and other tissues, causing more Xr to remain in the body.

Na+ retention, Na+, osmotic pressure, water

Although ACTH has a X effect on the adrenal cortex, it is not the X stimulus for the release of aldosterone. However, since ACTH helps maintain the adrenal cortex, it can indirectly have a positive effect on X production.

stimulatory, primary, aldosterone

The major stimulus for the release of aldosterone is a chemical called X formed in the renin-angiotensin aldosterone system (RAAS), which is summarized in Figure 16-8.

angiotensin II

imuli that initiate the RAAS include X and X. In response to low blood pressure, the kidneys release an enzyme called X (ren, kidney).It in turn, converts the plasma protein X, which is made in the liver, to X, so named because it stimulates blood vessels to constrict (angio, vessel; tensin, tension). This phenomenon is called vasoconstriction.

low blood pressure and low Na+ ion concentration in the blood renin, angiotensinogen, angiotensinogen 1

When angiotensin I passes through the lungs, an enzyme called X in the lung capillaries converts it to angiotensin II. In addition to being a potent X, angiotensin II acts as a powerful stimulator for the release of aldosterone.

ACE (angiotensin-converting enzyme), vasoconstrictor

glucocorticoids perform several vital functions, including

gluconeogenesis, glycogenesis, lipolysis, and proteolysis

The major glucocorticoid X), and it affects most body cells.

is cortisol (hydrocortisone

Cortisol X the uptake of glucose by most cells, thereby X the amount of blood glucose available for the brain.

inhibits, increasing

The stimulus for the release of cortisol is ACTH from the anterior pituitary; the stimulus for the release of ACTH is CRH from the hypothalamus; and the stimulus for the release of CRH is decreased blood glucose level. In turn, increasing levels of ACTH cause a decrease in the CRH secretion; thus, cortisol levels are regulated through negative feedback.

he third group of corticosteroids is the gonadocorticoids, which produce effects similar to those of X. Most gonadocorticoids are X, but some are X.

sex hormones, androgens or “male-generating” hormones (andro, male), estrogens.

ormones secreted from the adrenal medulla include two amino acid-based, water-soluble catecholamines: epinephrine and norepinephrine. Epinephrine (E; also called adrenaline) is the major hormone secreted from the adrenal medulla. Norepinephrine (NE, also called noradrenaline) is secreted to a lesser degree, and it generally causes effects similar to that of E (see Figure 16-10).

The medulla secretes X in response to X from the X nervous system.

E, neural stimulation, sympathetic

Acinar cells (“grape”) have a grape-like appearance and comprise most of the pancreas. They produce enzymes that travel to the small intestine through a duct, which accounts for the gland’s X function

exocrine

Dispersed among the acinar cells are clusters of cells called X.

pancreatic islets, or islets of Langerhans

All pancreatic hormones are X-based and X-soluble

amino acid, water

Glucagon secretion occurs in response to two stimuli.

Low blood glucose, high AA concentration, sympathetic activity

Insulin secretion occurs in response to three types of stimulation.

High glucose, parasym stimulation, or GIP.

Insulin stimulates X; however, if the body has adequate quantities of ATP, insulin can stimulate X in the liver and resting skeletal muscle.

glycolysis (oxidation of glucose), glycogenesis,

Insulin also affects lipid and protein metabolism. It inhibits an enzyme called hormone-sensitive lipase that promotes X in adipocytes (fat-storing cells). This , ensures that some of the energy-rich lipids absorbed during a meal will be X

lipolysis, available during interdigestive periods.

Somatostatin, which is the same as ,

growth hormone-inhibiting hormone (GHIH) released from the hypothalamus

pineal gland

secretes the hormone melatonin

Biogenic amines are

simple molecules derived from a single amino acid—either tyrosine or tryptophan

Somatostatin inhibits the release of

hGH and TSH from the pituitary gland, insulin and glucagon from the pancreas, and gastrin and VIP from the small intestine.

Eicosanoids primarily function as X chemicals.

paracrine

Ex of eicosanoids

Leukotrines, prostaglandins

The islets of langerhans contain four types of cells:

alpha, beta, delta, F

alpha cells secrete

glucagon;

beta cells secrete

insulin

delta cells secrete

somatostatin;

and F cells secrete

pancreatic polypeptide.

Insulin also facilitates the movement of glucose into X, which convert the glucose into X, and it inhibits X

adipocytes, lipids (lipogenesis), gluconeogenesis.

Hydrophilic hormones are Un/bound in the blood

unbound

Hydrophilic hormones have a slow/Fast clearance time

fast

hydrophilic hormones have a long/short latency period

short

hydrophilic hormones have a long/ Short-term effects

short

hydrophilic hormones Binds to X receptors

membrane-bound

Do hydrophilic hormones use 2nd messengers?

Yes

Do hydrophilic hormones Usually affects existing enzymes?

yes

Lipophilic hormones Most are X based (exceptX

lipid, TH

Lipophilic hormones Bound in the X

blood (proteins enhance water solubility)

Lipophilic hormones X clearance time

Slow

Lipophilic hormones X latency period

Long

Lipophilic hormones X term effects

Long-

Lipophilic hormones Binds to X receptors

intracellular

Lipophilic hormones X second messengers

Bypasses

Lipophilic hormones Usually X gene transcriptio

affects

Factors that remove hormones from the blood include:

Destruction by enzymes in the plasma Binding the hormone to target cells Removal by the liver or kidneys, which excrete the hormones from the body

Glucagon promotes s.

glycogenolysis, gluconeogenesis, and lipolysis

Glucose molecules released from the liver and consumed in the diet X blood glucose, which in turn inhibits the release of X

increase, glucagon.

When glucose levels in the blood are above normal, such as after a meal, hGH promotes X.

glycogenesis

Factors that cause the adrenal cortex to release aldosterone include (=

1) angiotensin II, which is formed in the pathway described below, (2) increasing K+ in the blood, (3) decreasing Na+ levels in the blood, and to a minimal extent, (4) ACTH.

At higher concentrations, cortisol inhibits white blood cell activity by X within these cells. In this way, cortisol can X associated with wounds and allergies.

stabilizing the membranes of lysosomes , reduce inflammation

PTH X blood Ca2+ concentration directly by stimulating X to secrete X, which dissolve the inorganic X of bone in the process of bone X.

increases, osteoclasts to secrete acids, calcium salts, resorption

PTH increases blood Ca2+ concentration indirectly by stimulating the kidney to convert X to X. Calcitriol stimulates the mucosal cells of the intestine to synthesize X, a Ca–binding protein, which facilitates the X of Ca2+ from food. PTH prevents a decrease in blood Ca2+ levels by inhibiting Ca2+ X by the kidneys.

calcidiol (vitamin D3), calcitriol (active vitamin D). calbindin, absorption, excretion

Androgens promote development of X and may be responsible for libido (“sex drive”) in women

male characteristics

Antagonistic hormones have X effects.

opposite

During stress, the circulating E prolongs the X initiated by sympathetic neurons. Stresses that activate the sympathetic nervous system and, thereby, cause the release of E and NE include X.

fight-or-flight responses, trauma, exercise, low blood pressure, and low blood glucose levels

Factors that decrease TRH secretion include X.

high levels of TH, fasting, high levels of iodine, and sympathetic activity

TH directly X TRH secretion and causes X of TRH receptors in the anterior pituitary, making the gland X responsive to TRH.

inhibits, down-regulation, less

Water-soluble hormones have a short latency period because they bind to X that initiate reactions in the cytoplasm involving the activation of X. Thus, there is no need to wait for X.

membrane-bound receptors, preexisting enzymes. transcription and translation

Water-soluble hormones usually have relatively short-lived effects because the preexisting enzymes they activate have already been X and may soon X

around for some time, degrade

Effects of E and NE include

widespread vasoconstriction, increased gluconeogenesis, glycogenolysis, lipolysis, and heart rate, dilation of bronchioles, and decreased digestive activity and urine output.

When blood glucose falls below normal, such as between meals, hGH X. Cells throughout the body then absorb the free fatty acids and convert them to acetyl compounds via X.

increases the catabolism of fats for energy and stimulates adipose tissue to hydrolyze fats (lipolysis), beta-oxidation

The acetyl compounds can enter the Krebs cycle reactions and promote ATP synthesis. Moreover, the liver can convert the glycerol component of fats to glucose via gluconeogenesis, which can increase the blood glucose concentration; thus, hGH has a hyperglycemic effect.

Ch 16 notes Flashcards

(114 cards)