Chemical Communication

Question 1

Local chemical signals

Answer 1

move by diffusion (“all chemical signals”) (from high concentration to low concentration) to influence target cells and tissues close by

Question 2

Histamine

Answer 2

a paracrine signal that has a role local immune system response. Its
production in response to allergens results in runny nose, itchy eyes and other allergy symptoms. Many medications employ the use anti-histamines to reduce the symptoms you experience

Question 3

Autocrine

Answer 3

(Same cell)

Stimulates cell originally secreted from autocrine

Question 4

Paracrine

Answer 4

(neighboring cells and tissues)

Question 5

Neurotransmitters

Answer 5

are a special type of local chemical signal is secreted by neurons. These signals are released over a short distance into a synapse, and influence other neurons or effector cells (glands, muscles)

Question 6

Acetylcholine

Answer 6

the neurotransmitter released by motor neurons to stimulate
skeletal muscle contraction

Question 7

Norepinephrine

Answer 7

an excitatory neurotransmitter released to influence other neurons

Question 8

Endocrine

Answer 8

(endo – within, krino – to secrete) chemical messengers (hormones)
are secreted into the blood stream and distributed throughout the body

this distribution allows for a whole body coordinated regulation of cell function in response to the chemical signal

distributed throughout the body

Question 9

Insulin

Answer 9

a protein hormone that regulates the full body uptake of glucose into
skeletal muscle , adipose (fat), liver and other cells in response to carbohydrate intake in the diet—decreased blood glucose

Pancreas releases insulin Into circulation when blood glucose levels are high

Insulin stimulates glucose uptake into muscle and adipose tissue
throughout the body bringing blood glucose levels back down

Question 10

Water-soluble

Answer 10

Dissolve in blood Short half lives—rapidly broken down by enzymes in bloodstream, many circulate as free hormones, dissolve into blood and delivered to target tissue

Rapid onset and short duration—many are large

Membrane bound receptor—need help across membrane

Ie/insulin

Polar

many circulate as free hormones, dissolve into blood and delivered to target tissue

Question 11

Lipid soluble

Answer 11

Circulate with binding proteins—slower activation

Long half life—days to weeks

Nuclear receptors

Ie/estrogen

Non-polar

Transport: small size, low solubility in aqueous solutions

Travel in bloodstream bound to binding proteins(chaperone molecule)

Reduces rate of degration—eventually removed

Question 12

Humoral

Answer 12

(means body fluids)

molecules and ions in circulating blood and stimulate or inhibit hormone release—the cells that secrete these hormones have receptors for certain substances in the blood

Ie/ blood glucose

Inhibition: release by same hormonal stimulus. Opposes the effect of secreted hormone to counteract

Question 13

Neural

Answer 13

neuron controls the release of hormone from a endocrine gland. Action potential in neuron releases neurotransmitter that stimulates hormone secretion

Follow AP neurons release a N+ into the synapse with the cells that produce the hormone

Sometimes a stimulus to increase hormone secretion

Neurons inhibit targets just as often as they stimulate targets

If NT is inhibitory, the target endocrine gland does not secrete its hormone

Question 14

Hormonal

Answer 14

hormone stimulates release of another hormone are called tropic hormones

Some hormones inhibit other hormones

Question 15

Humoral control example

Answer 15

Calcium ion (Ca++) levels in blood influence release of
Parathyroid hormone – which modifies calcium release from bone
- Influence can be stimulatory or inhibitory

When the blood level of a specific chemical changes (calcium), the hormone (PTH) is released in response to the chemicals concentration

Question 16

Neural control example

Answer 16

sympathetic nervous systems
influences release of epinephrine (adrenalin)(noepinephrine) from the adrenal gland – influences heart rate (increased heart rate, blood pressure, pupil dilation)

Ie/ in exercise, increased blood flow through exercising muscles. when exercise stops the neural stimulation declines and the secretion of epinephrine and noepinephrine decreases

Question 17

Hormonal control example

Answer 17

release of ACTH releasing hormone from hypothalamus (1) influences release of ACTH from the anterior pituitary (2), influencing release of cortisol from adrenal cortex.(3)

Hypothalamus—serves as a control center for automatic nervous system

1) neurons in hypothalamus release stimulatory hormones, called releasing hormones—travel in blood to anterior pituitary gland

2) releasing hormones stimulate release of hormones from anterior pituitary that travels in blood to the target endocrine cell

3) target endocrine cell secretes hormone into blood, where it travels to its target and produces a response

Anterior pituitary—made up of epithelial cells derived from embryonic oral cavity

Question 18

Why don’t all cells respond to a circulating hormone in the same way?

Answer 18

Cells that require a robust response to a particular hormone with have many receptors. We may even observe adaptation to increase the number of receptors on the cell surface, enhancing the response to a particular chemical signal—hormones exert their actions by binding to receptors—and only stimulate cells that have it

Receptors are also very specific to only one type of hormone

Only hormone 1 will bind to
a hormone 1 receptor

Only target cells with hormone 1 receptors will respond to the chemical message of hormone 1

Question 19

Lipid-soluble hormone travel

Answer 19

hormones can have receptors on the cell membrane or in the nucleus depending on whether the hormone is water soluble or lipid soluble.

Need membrane transporters to enter target cell

Their bind=nuclear receptor(in cytoplasm

Move to nucleus when activated.

interacts with DNA in nucleus or cellular enzymes to regulate transcription of certain genes

Takes mins-hours

Form transcription factor

Produce new proteins

Regulates transcription of specific MRNA molecules

Then move to ribosome for translation

Bind to nucleus receptors

Can penetrate through plasma membrane

Can pass right through membrane

steroid hormones, thyroid hormones Receptors inside cell, often influence DNA to drive protein production

Long half life

Influence hours, days

Long term change

steroid hormones, thyroid hormones Receptors inside cell, often influence DNA to drive protein production—travel with protein carrier

Question 20

Water-soluble hormone travel

Answer 20

hormones can have receptors on the cell membrane or in the nucleus depending on whether the hormone is water soluble or lipid soluble

Interact with membrane-bound receptor to initiate a response inside cell

Polar and can pass through cell membrane

receptor on cell surface – signal needs to be transmitted into cell.G proteins are activated by hormone binding receptor, stimulates production of cAMP, which actives enzymes (protein kinases) and cellular response

Membrane bound receptors make response through action of g-proteins

G-protein freely floats in cell membrane until it binds to its receptor

After hormone binds to receptor on outside of cell, receptor change shape—receptor binds to a G-protein.GTP binds to a subunit, thereby activating it

G-protein separates from receptor and activate a subunit separates from B and Y subunits. The activated a subunits activate adenylate cyclase, an enzyme that converts ATP to cAMP

Cyclic AMP functions as 2nd messenger

The amount of cAMP is present to produce a response in a cell is limited. Phosphodiesterase break down cAMP—AMP

Epinephrine – signal needs to be transmitted into cell. G proteins are activated by hormone binding receptor, stimulates production of cAMP, which actives enzymes (protein kinases) and cellular response

1) binds to receptor and activates G-protein which simulates adenyl cyclase to make large amount of cAMP from ATP

CAMP binds and activates target protein, which adds phosphates to specific proteins within the cell

Question 21

Membrane-bound

Answer 21

Hormone signal is cell is amplified through multistep, multiple enzyme process(can produce more than one output)– increasing impact on cell activity

Membrane bound receptors:
1) some receptors alter the activity of G-proteins at the inner surface of the cell membrane
2) other receptors directly alter the activity of intercellular enzymes—elicit specific responses in cell, ie/ 2nd messengers

Hormone signal is cell is amplified through multistep, multiple enzyme process

Minimal without amplification

Question 22

Anterior pituitary hormones

Answer 22

Growth Hormone (GH),
Thyroid Stimulating Hormone (TSH), and Adrenocorticotropic Hormone (ACTH)

Question 23

Posterior pituitary hormones

Answer 23

Antidiuretic Hormone (ADH)

Question 24

Thyroid gland hormones

Answer 24

Thyroid Hormone and Calcitonin

Highly vascular

Roles in modifying cellular metabolism rate and Ca2+ homeostasis

Synthesizes and secrets;
1.trilodothyronine
2.thyroxine
3.calcitonin

Question 25

Parathyroid gland hormones

Answer 25

Parathyroid Hormone

Question 26

Adrenal medulla hormones

Answer 26

Epinephrine and Norepinephrine

Question 27

Adrenal cortex hormones

Answer 27

Cortisol and Aldosterone Outer region of adrenal gland that secretes three classes of steroid hormones All 3 of steroid hormones enter their target cells and bind to nuclear receptor molecules

Question 28

Pancreas hormones

Answer 28

Insulin and Glucagon

Question 29

Insulin on target tissues

Answer 29

Insulin is secreted in response to high blood glucose – stimulates uptake of glucose from the blood into many different tissues Beta cell Ie/after a meal Skeletal muscle, cardiac muscle, cartilage, bone fibroblasts, blood cells, mammary glands—increased glucose uptake and glycogen synthesis; increases uptake of amino acids Liver— increases glycogen synthesis; increases use of glucose for energy Adipose cells—increases glucose uptake, glycogen synthesis, lipid synthesis Nervous system—has little effect except to increase glucose uptake in the satiety center

Question 30

Glucagon on target tissues

Answer 30

Glucagon is secreted in response to low blood glucose – stimulates release of glucose from stores in the liver into the blood Increased breakdown of glycogen and release of glucose into circulatory system Alpha cells Skeletal muscle, cardiac muscle, cartilage, bone fibroblasts, blood cells, mammary glands—has little effect Liver—causes rapid increase in the breakdown of glycogen to glucose and release of glucose into the blood; increases the formation of glucose from amino acids and, to some degree, from lipids; increases metabolism of fatty acids Adipose cells—high concentrations cause breakdown of lipids; probably unimportant under most conditions Nervous system—has no effect

Question 31

Delta cell

Answer 31

Secretes somatostatin

Question 32

Alpha cell

Answer 32

Secretes glucagon

Question 33

Beta cell

Answer 33

Secretes insulin

Question 34

Homeostasis disturbed—blood glucose levels increases

Answer 34

Stimulus—receptors and control center: Pancreas—pancreatic islets detect an increase in blood glucose and secrete insulin Intestine—digestive hormones(gastrin, secretin, cholecystokinin) stimulate insulin secretion Autonomic nervous system—parasympathetic stimulation of pancreas promotes insulin secretion Response—effectors;insulin stimulates glucose uptake by most tissues and promotes glycogen storage in skeletal muscle and liver.excess glucose is converted to adipose Homeostasis restored—blood glucose level decreases

Question 35

Homeostasis disturbed—blood glucose level decreases

Answer 35

Stimulus—receptors and control centers; Pancreas—pancreatic islets detect an decrease in blood glucose and do not secrete insulin Intestine—inactivity of the intestine decreases insulin secretion Autonomic nervous system—sympathetic stimulation of the pancreas inhibits insulin secretion, including during exercise Response—effectors; decreased insulin results in decreased glucose uptake, increased glycogen breakdown by liver and skeletal muscle, and increase glucose synthesis in the liver Homeostasis restored—blood glucose level increases

Question 36

Adrenal medulla

Answer 36

Inner part Adrenal medulla and adrenal cortex function separate endocrine glands Stimulates release of epinephrine 1) stress, physical activity, etc. stimulate the sympathetic nervous system Stimulation of hypothalamus by stress, physical activity or low blood glucose levels cause APs to travel through sympathetic nervous system to adrenal medulla Hormones bind to membrane—bound receptors in their target tissues, where they prepare body for intense physical activity Target tissue—heart, blood vessels, liver, adipocytes Adrenaline 20% of secretions, epinephrine 80% of secretions Response; Increased CO, increased blood flow to skeletal muscle and heart. Increased release of glucose and fatty acids into the blood. Constriction of blood vessels in skin and internal organs. Increased metabolic rate of several tissues Effects; Release stored NRG to support increased physical activity

Question 37

Adrenal gland location

Answer 37

Located on top of kidneys

Question 38

Pituitary gland location

Answer 38

At base of brain

Question 39

Anterior pituitary

Answer 39

Hormones secreted from hypothalamus influence release of AP AP hormones of influence release of other hormones from other endocrine glands Secretion of hormones regulated by releasing inhibiting hormones from the hypothalamus—pass through hypothalmic-pituitary control system—when neuropeptide hormone arrives at anterior pituitary gland, they leave blood and bind to membrane bound receptors—travel in blood to tissues

Question 40

Posterior pituitary

Answer 40

Under direct neural control from hypothalamus(hypothalmic) Extension of brain, composed of neurons Regulated by neural input AP travels through neurons ending store hormones in PP—AP cause release of this—hormones pass through circulatory system to target tissue Neural control of Hormone release dehydration detected by osmoreceptors of the Hypothalamus ADH released from posterior pituitary—transported via bloodstream Kidneys conserve water Blood vessels constrict to maintain blood pressure In kidney—reduced H2O volume causes increase H2O retention—to tack dehydration Blood vessels—increase vasoconstriction leads to increase blood pressure—to tack dehydration hypthalmic control regulated by neural input AP travels through neurons ending store hormones PP AP cause release of this hormones pass through circulatory ststem to target tissue

Question 41

Antidiuritic hormone

Answer 41

Binds to membrane bound receptors and increase H2O reabsorption by kidney tubles Results in less water loss as urine Vasopressin

Question 42

Oxytocin

Answer 42

Binds to membrane bound receptors and causes contraction of smooth muscle cells of uterus as well as milk let down from breast in lactating women

Question 43

Prolactin

Answer 43

Binds to membrane—bound receptors on cells of breasts Promotes development of breasts during pregnancy Stimulate production of milk

Question 44

Melanocyte-stimulating hormone

Answer 44

Binds to membrane bound receptors of melanocytes and causes them to stimulate melanin Skin to darken

Question 45

Growth hormone

Answer 45

Stimulates grow of bones, muscles and other organs Increase gene expression Slow protein breakdown

Question 46

Thyroid stimulating hormone

Answer 46

Binds to membrane bound receptors on thyroid gland Stimulates secretion of thyroid hormone Can stimulate growth of thyroid gland

Question 47

Adrenocorticotropic hormone

Answer 47

Binds to membrane bound receptors on cells of adrenal cortex Increase secretion of cortisol Required to keep adrenal cortex from degenerating Increases skin pigmentation

Question 48

Gonadotropins

Answer 48

Bind to membrane bound receptors on gonads Regulate growth, development, and functions of gonads LH and FSH. LH stimulates ovulation and reproduction hormones. FSH makes follicles and sperm cells

Question 49

Thyroid gland, parathyroid glands

Answer 49

Highly vascular Roles in modifying cellular metabolism rate and Ca2+ homeostasis Synthesizes and secrets; 1.trilodothyronine 2.thyroxine 3.calcitonin

Question 50

Parathyroid gland

Answer 50

Releases parathyroid hormone Essential for regulation of blood calcium levels Increases active vitamin D formation Increase blood calcium levels.stimulates them to reabsorb more bone Decreases loss of Ca2+ in urine

Question 51

Thyroid follicle

Answer 51

Epithelial cells here synthesize thyroid hormone Where hormone attached

Question 52

Parafollicular cell

Answer 52

Secrete cell tocin

Question 53

Thyroid hormones

Answer 53

Stress and hypothermia cause TRH to be released from neurons in hypothalamus TRH travels to anterior pituitary to stimulate secretion of TSH Increases Synthesis and T3 and T4 in general circulation They act on target tissue to produce response Thyroxine(T4), T3 is the only one that enters cytoplasm. Has direct effect on transcription

Question 54

Homeostasis disturbed—blood Ca2+ levels increase

Answer 54

Blood Ca2+ regulation—contraction and NT release Calcitonin lowers blood Ca2+—binds to membrane bound receptors of osteoclasts and inhibits them Stimulus—receptors and control centers; Parafollicular cell increase calcitonin secretion Parathyroid gland decrease PTH secretion Response—effectors; Decreased bone reabsorption and decreased uptake of Ca2+ from intestine and kidney result Homeostasis restored—blood Ca2+ levels decrease Back to homeostatic goal

Question 55

Homeostasis disturbed—blood Ca2+ levels decrease

Answer 55

Reduction in blood Ca2+ Stimulus—receptors and control centers; Parafollicular cells decrease calcitonin secretion Parathyroid gland increase PTH secretion Response—effectors; Increased bone reabsorption and increase uptake of Ca2+ from intestine and kidney result Ca2+ + phosphate—storage or Ca2+ we can pull from bones—lead to ostioporosis Homeostasis restored—blood Ca2+ levels increase Homeostatic level

Question 56

Mineralocorticoids

Answer 56

(Aldosterone) Minerals coming from cortex targets kidneys,intestine and sweat glands Produced in the greatest amounts Regulation of blood ion levels (minerals) Aldosterone – released when blood pressure is low, increases rate of Na+ reabsorption which increases water reabsorption (through osmosis) and blood fluid volume, returning blood pressure to normal Roles in K+ and H+ balance as well, will be discussed in Module 6 Mood fluid in blood increases blood pressure Increases H+ excretion into neurons, which lowers K+ levels

Question 57

Glucocorticoids

Answer 57

(Cortisol) Target tissues in liver, fat, skeletal muscle, immune tissues Regulation of fuel availability (glucose, free fatty acids) Cortisol – released in response to stress Cause lipid breakdown, reduce glucose and amino acid uptake into muscle, levels increase protein degradation and stimulate new glucose to be made in liver Increases blood nutrient levels Stimulate increase use of lipids and proteins Immune response—decreases number of WBC and secretion of inflammatory chemicals from the tissues Also reduce inflammation Increases glucose synthesis from a.a

Question 58

Adrenal androgens

Answer 58

Targets most tissues Stimulate development of male secondary sex characteristics • Not a focus of BPK 105 Insignificant in males, increases female sex drive, growth of pubic and axillary hair

Question 59

Secretion pathway of cortisol

Answer 59

1) low blood glucose and other stressors stimulate secretion of CRH CRH is released from hypothalmic neurons in response Passes by way of hypothalamohypophysial portal system to anterior pituitary 2)ACTH is secreted CRH binds to and stimulate cells that secrete ACTH 3)cortisol is secreted Once ACTH binds to its membrane bound receptors, adrenal cortex increases cortisol secretion 4)cortisol effects include increases in available energy to cells Increases breakdown of lipids in proteins Higher glucose levels and increases antiflammatory effects 5)negative feedback by cortisol and ACTH reduced CRH Inhibits CRH secretion from hypothalamus

Question 60

posterior pituitary neural control of hormone release

Answer 60

dehydration deteted by osmoreceptors of the hypothalamus ADH released from posterior pituitary kidneys conserve water blood vessels constrict to maintain blood pressure