Endocrine System (New) Chapter 16 Flashcards
(79 cards)
1
Q
pWhat is the Endocrine System, and through what does it function?
A
It acts with the nervous system to coordinate and integrate activity of body cells.
Hormones transported in blood influences metabolic activity.
2
Q
What five actions that the Endocrine system control and integrate?
A
- Reproduction.
- Growth and development.
- Maintenance of electrolyte, water (through antidiuretic hormone), and nutrient balance in blood.
- Regulation of cellular metabolism and energy balance.
- Mobilization of body defenses.
3
Q
What are the differences between Exocrine Glands and Endocrine Glands.
A
Exocrine:
1. Produces non hormonal substances such as sweat and saliva;
2. Presence of ducts that carry secretion to membrane surface.
Endocrine:
1. Produce hormones;
2. Lacks ducts.
4
Q
Name 5 Endocrine Gland, and 1 neuroendocrine organ.
A
- Pituitary Gland (Inferior to hypothalamus)
- Thyroid Gland
- Parathyroid Gland
- Adrenal (Behind the kidneys)
- Pineal Gland
- Hypothalamus
5
Q
Name three organs that have both endocrine and exocrine function.
A
- Pancreas
- Gonads; Testes and ovaries
- Placenta
6
Q
What are hormones?
A
Long-distance chemical signals that travel in blood or lymph, that alter target cell activity
7
Q
What are autocrine?
A
Chemicals that act effects on the same cells that secrete them.
8
Q
What are paracrines?
A
Chemicals that affect cells other than the ones that secretes them.
9
Q
What are the two main classes of hormones?
A
- Amino acid-based hormones; Amino acid derivatives, peptide hormones, proteins.
- Lipid derivative hormones; Steroids from cholesterol and eicosanoids from arachidonic acid.
10
Q
What are target cells?
A
Cells with receptors that bind with a specific hormones.
11
Q
What are the five action of Hormones on Target Cells?
A
1.Change plasma membrane permeability/membrane potential by opening or closing ion channels.
2. Stimulate synthesis of enzyme or proteins.
3. Activate or deactivate enzyme activity.
4. Induce secretory activity.
5. Stimulate mitosis
12
Q
What are two types of hormones and what do they do?
A
Water-soluble hormones (All amino acid-based hormones but thyroid hormone; Cannot enter the cell, act on receptors on the plasma membrane, and via G protein second messengers.
Lipid soluble hormones (Steroid and thyroid hormones). Act on intracellular receptors that directly activate genes. Can enter cells.
13
Q
What are the eight steps when an Amino Acid-based hormone bind with receptors using Cyclic AMP?
A
- Hormone (First messenger) binds to the receptor.
- Receptor then activates G protein;
- G protein activates or inhibits effector enzyme ADENYLATE CYCLASE;
- Adenylate Cyclase coverts ATP to cAMP (Second messenger
- cAMP activates kinases which phosphorylate with other proteins
- Phosphorylated proteins are either activated or inactivated.
- cAMP is degraded by PHOSPHODIESTERASE, stopping cascade.
- Cascade have huge amplification effects.
14
Q
What are the four steps when an Amino Acid-based hormone bind with receptors using PIP2-calcium signaling mechanism?
A
- Hormone-activated G protein activates effector enzymes phospholipase C.
- Activated phospholipase splits proteins, PIP2, into two second messengers
- Diacylglycerol which activates protein kinases
- Inositol triphosphate which makes Ca2+ release from intracellular storage site. - Calcium ions act as another second messenger as they alter enzyme activity and channels or bind to calmodulin, a regulatory protein.
- Calcium-bound calmodulin activates enzymes that amplify cellular response.
15
Q
What are other signaling mechanisms?
A
cGMP
Hormones without second messengers:
Insulin receptor is tyrosine kinase enzime, activated tyrosine kinases provide docking sites for relay proteins that trigger cell responses.
16
Q
What are four steps when a Lipid-soluble and thyroid hormones binds with receptors.
A
- Lipid-soluble hormone and thyroid hormone diffuse into target cells and bind with intracellular receptors
- Receptor-hormone complex/bind enters nucleus and binds to DNA
- This helps DNA transcription to produce mRNA
- mRNA is then translated into specific protein.
17
Q
Blood levels of hormones are controlled by? And what do they mean?
A
Negative feedback; Increased hormones effects on target organs can inhibit further hormone release.
18
Q
What are the two things that release hormones?
A
- Endocrine Gland stimuli.
- Nervous system modulation.
19
Q
Under the endocrine gland, what are the three stimuli?
A
- Humoral stimuli
- Neural stimuli
- Hormonal stimuli
20
Q
What is Humoral Stimuli and give an example of the hormone.
A
When there is a change of ions and nutrient level in blood, which directly stimulate secretion of hormones.
Example: Low Ca2+ level, parathyroid gland secretes PTH, which causes Ca2+ levels to rise.
21
Q
What is Neural stimuli and give an example of the hormone.
A
Nerve fibers stimulate hormone release.
Example: Sympathetic nervous system fibers stimulate adrenal medulla to secrete catecholamines.
22
Q
What is Hormonal Stimuli, and give an example of the hormone.
A
Hormones stimulate other endocrine organs to release hormones.
Hypothalamic hormones stimulate release of anterior pituitary hormones, APH stimulate target organs to release their hormones.
23
Q
What is Nervous System Modulation?
A
The nervous system can make adjustments to hormone levels when needed; either stimulating or inhibiting endocrine glands.
Example: During fight or flight
24
Q
What are target cells and what three factors do they depend on?
A
Target cells are receptors that bind with hormones.
1. Blood level of hormones
2. Number of receptors in target cells
3. Strength of binding between receptors and hormones.
25
What is up-regulation and down-regulation
Up: More receptors are formed when there is low hormone level. Receptors become more sensitive.
Down: Less receptors are formed when there is higher hormone level.
26
What is the difference between Steroids and Thyroid hormones, and amino acid-based hormones in terms of blood circulation?
Steroids and Thyroid hormones circulate the blood attached to a carrier/transport/plasma protein
Others roam around freely.
27
What are three ways in which hormones can be removed?
1. Degrading enzymes
2. Kidney
3. Liver.
28
What are the three different interactions of hormones at target cells and what do they mean?
Give examples.
1. Permissiveness; one hormone needs another hormone to exert its effects.
Example: Reproductive hormones need thyroid hormone to exert its effects
2. Synergism; more than one hormone can exert its effect on target cells causing amplification.
Example: Glucagon and epinephrine both cause liver to release glucose.
3. Antagonism: One or more hormones oppose another hormone.
Example: Insulin and glucagon.
29
What connects the Hypothalamus to the Pituitary Gland?
The Infundibulum
30
What is another name for Anterior lobe of Pituitary Gland and Posterior lobe of Pituitary Gland
AP: Neurohypophysis
PP: Adenohypophysis
31
What is the name that connects the hypothalamus to the posterior lobe of P.G. and where does it arise and runs through?
The hypothalamic-hypophyseal tract arises from paraventricular and supraoptic nuclei and runs through the infundibulum.
32
What two hormones are stored in the posterior lobe of P.G.
Oxytocin and Antidiuretic hormones stored in the axon terminals of Posterior lobe and released into blood.
33
What are the THREE steps of Hypothalamus Release of Hormones into the POSTERIOR PITUITARY LOBE
1. Hypothalamic neurons synthesize oxytocin and ADH.
2. The hormones are moved down the axons through the hypothalamic-hypophyseal tract into the posterior pituitary.
3. Hormones are stored in the axon terminal of P.P.G
34
What are the THREE steps of Hypothalamus Release of Hormones into the ANTERIOR PITUITARY LOBE.
1. Hypothalamic neurons secrete releasing or inhibiting hormones into the primary capillary plexus.
2. Hormones travel through the hypophyseal portal veins which stimulates or inhibits release of hormones made in the Anterior Pituitary Lobe
3. A.P.L secretes hormones through the secondary capillary plexus in response to releasing hormones
35
Name the three tracts to Anterior Lobe of Pituitary Gland.
Primary capillary plexus.
Hypophyseal portal veins
Secondary capillary plexus.
36
What does oxytocin and Antidiuretic hormones do and how many amino acids do they have.
Oxytocin: Stimulate contraction of uterus during birth, act as hormonal trigger for milk ejection. Uses PIP2-calcium second messenger system.
Antidiuretic (Vasopressin):
1. Targets kidney to reabsorb more water to inhibit urine formation because the hypothalamus has osmoreceptors that monitor solute concentration.
2. Triggered by pain, low-blood pressure, and drugs.
3. High concentration of solutes causes vasoconstriction which narrows the blood vessels.
4. Inhibited by alcohol and diuretics.
37
What are three facts about Anterior Pituitary Hormones.
1. All six of the hormones are peptide hormones.
2. All but growth hormones target cell via cAMP second messenger system.
3. All are tropic hormones but two that regulate secretion of other hormones. Prolactin and Growth hormones are not tropic.
38
What are the six hormones released by Anterior Pituitary Lobe
1. Growth hormone
2. Thyroid-stimulating hormones
3. Adrenocorticotropic hormones
4. Follicle-stimulating hormones
5. Luteinizing hormones
6. Prolactin
39
What is another name of the Growth Hormone and what are three action of the hormone?
Somatotropin as they are produced by somatotropic cells.
Actions:
1. Decrease rate of cellular glucose uptake and metabolism (Opposite of Insulin)
2. Triggers liver to breakdown glycogen to glucose.
3. Increase blood levels of fatty acids for fuel and cellular protein synthesis
40
Who regulates secretion of Growth Hormones and what happens and what triggers it?
Hypothalamic hormones (Growth Hormone - Releasing Hormone or Growth Hormone - Inhibiting Hormone ) regulate production of Growth hormones on somatotropic cells.
GHRH stimulates GH release when triggered by low blood GH or glucose, or high amino acid level
GHIH inhibit GH release when increase level of GH and Insulin-Like Growth Factor
41
Who regulates secretion of THYROID-STIMULATING HORMONE and what happens and what triggers it?
AKA Thyrotropin produced by Thyrotropic cells, which stimulates development and secretory activity in thyroid.
Triggered by Thyrotropin-releasing hormone from hypothalamus.
Inhibited by rising blood levels of thyroid hormones and GHIH.
42
Who regulates secretion of ADRENOCORTICOTROPIC Hormone (ACTH) and what happens and what triggers it?
AKA Corticotropin produced by corticotropic cells. Triggered by corticotropin-releasing hormone
ATCH stimulates the adrenal cortex to release corticosteroids.
Alter release of CRH when fever, hypoglycemia, stressors
43
Who regulates secretion of FSH and LH and what happens and what triggers it?
AKA Gonadotropins, Follicle-stimulating hormones and luteinizing hormones are produced by gonadotropic cells.
FSH: Produces sex cells (Sperm and egg)
LH: Stimulates gonadal organs to produce gonadal hormones, helps mature eggs, triggers ovulation, release of estrogen and progesterone in females. Releases testosterone in males.
Triggered by gonadotropin-releasing hormone (GnRH)
Suppressed by gonadal hormone
44
Who regulates secretion of PROLACTIN Hormones and what happens and what triggers it?
Regulate prolactin cell by prolactin-inhibiting hormone (Dopamine) of the Hypothalamus.
Prolactin stimulates milk production in females
Action:
Increased estrogen level stimulates prolactin
Suckling stimulates PRL release and promotes continued milk production.
45
What is the Isthmus, Follicle, Colloid and Parafollicular cells do?
Isthmus: Connects two lateral thyroid lobes
Follicles: Has follicular cells that produce thyroglobulin (glycoproteins)
Colloid: Contains thyroglobulin plus iodine
Parafollicular cells: Produce hormones calcitonin
46
What three Hormones are found in Thyroid?
1. T3 - Triiodothyronine: Two tyrosine with 3 iodine atoms
2. T4 - Thyroxine: Two tyrosine with 4 iodine atoms
3. Calcitonin
47
What three effects do thyroid hormones have and their target cells?
Thyroid hormones enter target cell and bind to intracellular receptors within nucleus which activates transcription of metabolic genes.
Effects:
1. Increasing basal metabolic rate and heat production (calorigenic effect)
2. Regulates tissue growth and development
3. Maintains blood pressure.
48
What are the seven steps to synthesize Thyroid Hormones?
1. Thyroglobulin is synthesized and enters follicle lumen.
2. Iodide is trapped and released into lumen
3. Iodide is oxidized, removing electrons converting to Iodine (I^2)
4. Iodine attaches to tyrosine by peroxidase enzymes forming Monoiodotyrosine or Diiodotyrosine
5. Iodinated tyrosines link to form T3 (Triiodothyronine) and T4 (Thyroxine), one MIT and one DIT forms T3, two DIT forms T4.
6. Colloid is endocytose follicular cells
7. Lysosomal enzyme cleave T3 and T4 from thyroglobulin.
49
What chemical substance transport T3 and T4 hormones?
Thyroxine-binding globulins (TBGs)
T3 is 10 times more active than T4
peripheral tissues have enzyme that convert T4 to T3, enzyme removes one iodine.
50
How is Thyroid Hormone regulated?
Low level of thyroid hormones stimulate release of thyroid-stimulating hormones.
Rising TH level provide negative feedback on TSH, which can also be inhibited by GHIH, dopamine, and increase level of cortisol and iodide
Hypothalamic Thyroid-stimulating hormone can overcome negative feedback during pregnancy or exposure to cold.
51
What does Calcitonin hormone do?
Produced by parafollicular cells in response to high Calcium ion levels.
Inhibits osteoclast activity and prevents release of Calcium ion from bone matrix
Stimulates Calcium ion uptake into bone matrix.
52
What cells make up the Thyroid Gland and what hormones does it produce?
Oxyphil cells and parathyroid cells make up the Thyroid Glands.
Secretes Parathyroid hormones which is secreted in response to low calcium ion level.
Target organs are skeleton, kidney and intestine.
53
What are three functions of the Parathyroid Hormone?
1. Stimulate osteoclast to breakdown bone matrix to release calcium ion in the blood.
2. Enhances resorption of calcium ion and secretion of phosphate by KIDNEYS
3. Promotes activation of vitamin D by kidneys, leads to increase absorption of Calcium ion.
54
What are the two parts in the Adrenal Gland and what are they?
1. Adrenal Cortex; three layer of tissue that secretes different hormones.
2. Adrenal Medulla; Nervous tissue that is part of the sympathetic nervous system.
They produce corticosteroids hormone.
55
What are the three layers of Adrenal Cortex cells and what corticosteroids they produce?
1. Zona Glomerulosa: Mineralocorticoids.
2. Zona Fasciculata: Glucocorticoids.
3. Zona Reticularis: Gonadocorticoids.
56
What hormones are released by the three layers of Adrenal cortex?
1. Zona Glomerulosa: Aldosterone
2. Zona Fasciculata: Cortisol
3. Zona Reticularis: Androgens
57
What does Aldosterone do?
It is in the Zona Glomerulosa, the mineralocorticoids cell produce Aldosterone which stimulate Na reabsorption by kidneys, which increases blood pressure and volume.
- It also eliminates potassium by kidneys.
58
What four factors that regulate aldosterone secretions?
1. Renin-angiotensin-aldosterone mechanism: Decreases B.P. , cell release renin into blood
2. Plasma concentration of potassium ion: Increase potassium level stimulates Zona Glomerulosa cells to release Aldosterone
3. Adrenocorticotropic hormone
4. Atrial natriuretic peptide: Secreted by heart in response to H.B.P. which blocks renin and aldosterone secretion to decrease blood pressure.
59
What three factors regulates the secretion of Cortisol?
1. Cortisol is released in response to Adrenocorticotropic hormones (ACTH)
2. Acute stress
3. CNS override cortisol inhibition of ACTH and CRH.
60
What functions does cortisol have?
1. Increase blood levels of glucose, fatty acids, and amino acids.
2. Metabolism (Gluconeogenesis) which is the formation of glucose from fat and protein
3. Enhance vasoconstriction which raises blood pressure to quickly distribute nutrients to cells
61
What three functions do Gonadocorticoids (Adrenal Sex Hormones) have.
1. Produces Androgens (Estrogen, Progesterone and Testosterone),
2. Contributes to puberty and appearance
3. Sex drive in women
4. Source of estrogens in postmenopausal women.
62
What cells does the Adrenal Medulla have and what to they synthesize?
Adrenal medulla synthesize CATECHOLAMINES: Epinephrine and Norepinephrine.
63
What four effects does catecholamines do?
1. Vasoconstriction (Blood vessels narrowing)
2. Increased heart rate
3. Increase blood glucose level.
4. Blood diverted to brain, heart and skeleton.
64
What are the differences between Epinephrine and Norepinephrine?
Epinephrine: Stimulator of metabolic activities
Norepinephrine: Influence peripheral vasoconstriction and blood pressure.
65
What cell secretes the hormone in Pineal Gland, and name the hormone
Pinealocytes (cells) secrete melatonin (hormone) derived from serotonin.
66
What are four factors that are affected by Melatonin?
1. Timing of maturation and puberty
2. Day/Night Cycle
3. Process that show rhythmic variations
4. Production of antioxidants
67
What cells in the pancreas release hormones?
1. Acinar cells (exocrine) produce enzyme juice for digestion
2. Pancreatic islets contain endocrine cells.
68
What cells are produced in the Pancreatic Islets
1. Alpha cells produce glucagon (hyperglycemic cells)
2. Beta cells produce insulin (hypoglycemic hormones)
69
How is glucagon triggered and what does it do?
1. Triggered by low glucose level, increasing amino acid level, or sympathetic nervous system.
2. Targets liver to breakdown glycogen into glucose (glycogenolysis), synthesize glucose from lactic acid (Gluconeogenesis), releases glucose into blood.
70
How is insulin triggered and what does it do?
1. Triggered when blood glucose level increases/
2. Enhance membrane transport of glucose into fat and muscle cells.
3. Inhibits breakdown of glycogen into glucose
4. Inhibits conversion of amino acids or fats to glucose.
71
What five factors influence insulin release?
1. Increase blood glucose level
2. Rising blood levels of amino acids and fatty acids
3. Release of ATH
4. Hormones glucagon, epinephrine, norepinephrine thyroxine, and glucocorticoids.
5. Somatostatin and sympathetic nervous system inhibiting insulin release.
72
What hormones do ovaries produce and what do they do?
1. Estrogen (Maturation of reproductive organs, appearance of sexual characteristics)
2. Progesterone: Breast development and cyclic changes.
73
What hormones do the testes produce?
Testosterone:
1. Maturation of male reproductive organs
2. Sex drive and sexual characteristics in males
3. Need for normal sperm production
4. maintains reproductive organs state.
74
What hormones do Adipose Tissue release?
1. Leptin: stimulates increased energy expense
2. Resistin: Insulin antagonist
3. Adiponectin: enhances sensitivity to insulin.
75
What hormones do Gastrointestinal tract produce?
1. Gastrin stimulates release of HCL
2. Gherkin stimulates food intake
3. Secretin stimulates liver and pancreas
4. Cholecystokinin activates pancreas, gallbladder
5. Incretins enhance insulin release and inhibit glucagon
76
What hormones does the heart and kidneys produce?
Heart: Antrial natriuretic peptide
Kidneys:
Erythropoietin (production of RBC)
Renin (initiates R-A-A)
77
Skeleton
Osteocalcin:
Low levels of osteocalcin are present in type 2 diabetes.
Improves glucose, reduces body fat
78
Skin
Cholecalciferol, precursor vitamin D
Caltriol: active for of vitamin D that absorbs calcium
79
Thymus
Thymulin, thymopoietins and thymosins are involved in development of T lymphocytes
