Chapter 16 Endocrine System Flashcards
1
Q
Hormones of the anterior pituitary gland
A
FSH, LH, ACTH, GH, Prolactin, TSH
2
Q
Hormones of the posterior pituitary gland
A
Oxytocin and ADH
3
Q
How are the anterior and posterior lobes regulated?
A
Anterior-via hormones
Posterior-nerves
4
Q
Hormones released by the hypothalamus:
A
Growth hormone releasing hormones, Prolactin releasing/inhibit hormone,…
5
Q
How are posterior/anterior pituitary gland connected to the hypothalamus?
A
Anterior–hypothalmic-hypophyseal tract
Posterior–hypophyseal portal system
6
Q
Function of growth hormone
A
Stimulate growth (epithelial plate)
7
Q
Function of prolactin
A
Stimulate milk production in mammary glands
8
Q
Function of thyroid stimulating hormone
A
Stimulate the thyroid gland to release: T3, T4, Calcitionin, regulated via neg. feedback
9
Q
Function of the ACTH
A
Release corticosteroids,targets adrenal cortex, reabsorb more water to inhibit or prevent urine formation, release also triggered by pain, low blood pressure, and drugs
10
Q
Function of Follicle Stimulating Hormone
A
Production of gamets (egg or sperm)
11
Q
Function of lutineizing hormone
A
Promotes production of gonadal (sex hormones)–progesterone/estrogen, testosterone
12
Q
Hormones of the posterior pituitary gland
A
Oxytocin
ADH
13
Q
Function of oxytocin
A
milk ejection & uterine contraction, pos. feedback
14
Q
Function of ADH
A
regulates fluid output, targets kidney tubules to reabsorb water, inhibited by alcohol
15
Q
Hyper and Hypo secretion GH
A
Hyper–gigantism or acromegaly
Hypo–pituitary dwarfism
16
Q
Hyper and hypo secretion TSH
A
Graves disease (popped out eyes) Infantile hypothyroidism ( in infants which have swollen mouth and nose)
17
Q
Function and target of PTH
A
Activate osteoclasts to release Ca2+ => increases blood Ca levels, antagonist to calcitonin
18
Q
2 portions of the adrenal gland
A
Adrenal cortex and adrenal medulla
19
Q
hormones of the adrenal cortex
A
mineral corticoids (aldosterone), glucocorticoids, and gonadoncorticoids
20
Q
Hormones of the adrenal cortex
A
Mineral corticoids (aldosterone), glucocorticoids, and gonadocorticoids
21
Q
Layers of adrenal cortex
A
Glomerulosa
fasciuclata
reticularis
(Girls Facetime Rats)
22
Q
Hormones of glomerulosa, fasciuclata, and reticularis
A
Glomer–mineralcorticooids (aldosterone & reninangiotensin), fasciculata (CRH), reticularis (testosterone, estrogen)
23
Q
Hormones of the adrenal medulla
A
Epinephrine and nor epinephrine
24
Q
Which of the following is NOT a category of endocrine gland stimulus? A) hormonal B) enzymatic C) neural D) humoral
A
B) enzymatic
25
```
Chemical substances secreted by cells into the extracellular fluids that travel through the blood and regulate the metabolic function of other cells in the body are called _____.
A) antibodies
B) hormones
C) enzymes
D) proteins
```
B) hormones
26
The hypothalamic-hypophseal tract _____.
A) runs through the infundibulum
B) conducts aldosterone to the hypophysis
C) connects the hypophysis to the pituitary gland
D) is the site of prolactin synthesis
A) runs through the infundibulum
27
```
Which of the following is NOT a cardinal sign of diabetes mellitus?
A) polyphagia
B) polydipsia
C) polycythemia
D) polyuria
```
C) polycythemia
28
Oxytocin _____.
A) exerts its most important effects during menstruation
B) release is an example of a positive feedback control mechanism
C) controls milk production
D) is an anterior pituitary secretion
B) release is an example of a positive feedback control mechanism
29
```
Anti-diuretic hormone (ADH) _____.
A) secretion is inhibited by alcohol
B) promotes dehydration
C) is produced by the anterior pituitary
D) increases urine production
```
A) secretion is inhibited by alcohol
30
The ability of a specific tissue or organ to respond to the presence of a hormone is dependent on ______.
A) the location of the tissue or organ with respect to the circulatory path
B) the presence of the appropriate receptors on the cells of the target tissue or organ
D) nothing--all hormones of the human body are able to stimulate any and all cell cell types because hormones are powerful and nonspecific
B) the presence of the appropriate receptors on the cells of the target tissue or organ
31
```
Which anterior pituitary hormone does NOT target another endocrine gland?
A) luteinizing hormone
B) follicle-stimulating hormone
C) adrenocorticotropic hormone (ACTH)
D) growth hormone
```
D) growth hormone
32
```
One of the least complicated of the endocrine control systems directly responds to changing blood levels of ions and nutrients. Which of the following describes this mechanism?
A) protein synthesis
B) carbohydrate oxidation
C) catabolic inhibition
D) humoral stimulation
```
D) humoral stimulation
33
```
The major targets of growth hormone are _____.
A) the adrenal glands
B) the blood vessels
C) the liver and gall bladder
D) bones and skeletal muscles
```
D) bones and skeletal muscles
34
```
Which organ is responsible for synthesizing the hormone atrial natriuretic peptide (ANP)?
A) the skin
B) the spleen
C) the heart
D) the kidney
```
C) the heart
35
```
The most important mineralocorticoid regulator of electrolyte concentrations in extracellular fluids is _____.
A) cortisol
B) insulin
C) glucagon
D) aldosterone
```
D) aldosterone
36
```
The single most important regulator of calcium levels in the blood is _____.
A) calcitonin
B) gonadotropic hormones
C) thyroid hormone
D) parathyroid hormone
```
D) parathyroid hormone
37
```
Which of the following can act on receptors inside the target cell that directly activate specific genes?
A) growth hormone
B) calcitonin
C) melatonin
D) testosterone
```
D) testosterone
38
```
Several hormones are synthesized in the hypothalamus and transported to the anterior pituitary gland. The mechanism of transportation form hypothalamus to anterior pituitary gland is through the _____.
A) general circulatory system
B) feedback loop
C) hypophyseal portal system
D) hepatic portal system
```
C) hypophyseal portal system
39
```
In circumstances where the body requires prolonged or increased levels of a hormone, the DNA of target cells will specify the synthesis of more receptors on the surface of the cells of the target organ. This is known as _______.
A) sensitivity increase
B) a stressor reaction
C) up-regulation
D) cellular affinity
```
C) up-regulation
40
```
What ion is sometimes used as a second messenger of amino acid-based hormones?
A) chlorine
B) calcium
C) sodium
D) iron
```
B) calcium
41
```
John tells you that cholesterol is bad and should be eliminated from the diet. You explain to him that cholesterol is important. Which of the following hormones are synthesized from cholesterol?
A) thryoxine
B) growth horomone
C) oxytocin
D) testosterone
```
D) testosterone
42
```
Which hormone has only one know effect: to stimulate milk production by the breasts?
A) prolactin
B) oxytocin
C) estrogen
D) progesterone
```
A) prolactin
43
```
During an afternoon class, Lisa starts to feel hungry and worries that her blood sugar level may be dropping. Which hormone is helping prevent a drop in blood sugar level?
A) aldosterone
B) thyroxine
C) insulin
D) glucagon
```
D) glucagon
44
Polyphagia
excessive hunger
45
Polydipsia
excessive drinking
46
Polycythemia
a condition marked by an abnormal increase in the number of circulating red blood cells especially
47
Polyuria
The excessive passage of urine
48
Water-soluble hormones (all amino acid-based hormones except thyroid hormone)
Act on plasma membrane receptors
Act via G protein second messengers
Cannot enter cell
49
Lipid-soluble hormones (steroid and thyroid hormones)
Act on intracellular receptors that directly activate genes
| Can enter cell
50
What are the three stimulis that stimulate to sythesize and release hormones in response?
Humoral stimuli
Neural stimuli
Humoral stimuli
51
Humoral stimuli
Changing blood levels of ions and nutrients directly stimulate secretion of hormones
Example: Ca2+ in blood
~ declining blood Ca2+ concentration stimulates parathyroid glands to secrete PTH (parathyroid hormone)
~ PTH causes Ca2+ concentrations to rise, and stimulus is removed
52
Neural stimuli
Nerve fibers stimulate hormone release
| ~ Sympathetic nervous system fibers stimulate adrenal meulla to secrete catecholamines
53
Hormonal stimuli
Hormones stimulate other endocrine organs to release their hormones
~ Hypothalamic hormones stimulate release of most anterior pituitary hormones
~ Anterior pituitary hormones stimulate targets to secrete still more hormones
~ Hypothalamic-pituitary-target endocrine organ feedback loop
* Hormones from final target organs inhibit release of anterior pituitary hormones
54
Target cell activation depends on three factors
1. Blood levels of hormone
2. Relative number of receptors on/in target cell
3. Affinity (strength) of binding between receptor and hormone
55
Hormones can be removed from blood by:
Degrading enzymes or
kidneys or
liver
~ Half-life: time required for level of hormone in blood level to decrease by half
*varies anywhere from faction of a minute to a week, depending on hormone
56
Permissiveness:
one hormone cannot exert its effects without another hormone being present
~ Example: reproductive hormones need thyroid hormone to have effect
57
Synergism:
More than one hormone produces same effects on target cell, causing amplification
~ Example: glucagon and epinephrine both cause liver to release glucose
58
How many hormones does pituitary anterior lobe secrete?
```
6 hormones
~ Growth hormone (GH)
~ Thyroid-stimulating hormone (TSH)
~ Adrenocorticotropic hormone (ACTH)
~ Follicle-stimulating hormone (FSH)
~ Luteinizing hormone (LH)
~ Prolactin
```
59
How many hormones does pituitary posterior lobe secrete?
2 hormones
~ oxytocin
~ ADH
60
Diabetes insipidus
ADH deficiency due to damage to hypothalamus or posterior pituitary
Must keep well hydrated
61
Hyper secretion of GH is usually caused by anterior pituitary tumor
In children results in gigantism
| In adults results in acromegaly
62
Hypo secretion of GH
In children results in pituitary dwarfism
| In adults usually causes no problems
63
Gonadotropins (FSH and LH)
They are secreted by gonadotropic cells of anterior pituitary
64
What does FSH stimulate?
FSH stimulates production of gametes (egg or sperm)
65
What does LH promote?
In females, LH helps mature follicles of egg, triggers ovulation and release of estrogen and progesterone
In males, LH stimulates production of testosterone.
66
Is hypersecretion of prolactin more common than hyposecretion?
TRUE
67
Hyperprolactinemia
is the most frequent abnormality of anterior pituitary tumors
68
Thyroid Hormone (TH)
Body's major metabolic hormone
Found in two forms
~ T4 (thyroxine): major form that consists of two tyrosine molecules with four bound iodine atoms
~ T3 (Triiodothyronine): form that has two tyrosines with three bound iodine atoms
Both are iodine-containing amine hormones
69
Effects of thyroid hormone include:
Increase basal metabolic rate and heat production
~ Referred to as calorigenic effect
Regulates tissue growth and development
~ Critical for normal skeletal and nervous system development and reproductive capabilities
Maintains blood pressure
~ Increases adrenergic receptors in blood vessels
70
Thyroid hormone Synthesis
Thyroid gland stores hormone extracellulary in follicle lumen until triggered by TSH to release
1. Thyroglobulin is synthesized and discharged into follicule lumen
2. Iodid is trapped: iodide ion (I-) are actively taken into cell and released into lumen
3. Iodide oxidized: electrons are removed, converting it to iodine
4. Iodine is attached to tyrosine: mediated by peroxidase enzymes
~ Monoiodotyrosine (MIT): formed if only one iodine attaches
~ Diiodotyrosine (DIT): formed if two iodines attach
5. Iodinated tyrosines like together to form T3 and T4
~ If one MIT and one DIT link, T3 is formed
~ If two DITs link, T4 is formed
6. Colloid is endocytosed by follicular cells
~ Vesicle is then combined with a lysosome
7. Lysosomal enzymes cleave T3 and T4 from thyroglobulin
~ Hormones are secreted into bloodstream
~ Mostly T4 secreted, but T3 is also secreted
~ T4 must be converted to T3 at tissue level
71
Transport and Regulation of thyroid hormone
T4 and T3 transported by thyroxine-binding globulins
| TH release is regulated by negative feedback
72
Hypo secretion of TH in adults
Myxedema
Symptoms include low metabolic rate, thick and/or dry skin, puffy eyes, feeling chilled, constipation, edema, mental sluggishness, lethargy
73
Hypo secretion of TH in infants
Cretinism
| Symptoms include intellectual disabilities, short and disproportionately sized body, thick tongue and neck
74
Hyper secretion of TH
Most common type is Graves' disease
75
What are the functions of the parathyroid gland?
Stimulate osteoclasts to digest bone matrix and release Ca2+ to blood
Enhances reabsorption of Ca2+ and secretion of phosphate (PO43-) by kidneys
Promotes activation of vitamin D by kidneys, which leads to increased absorption of Ca2+ by intestinal mucosa
76
Three layers of cortical cells produce the different corticosteroids
Zona glomerulosa—Mineralocorticoids
Zona fasciculata—Glucocorticoids
Zona reticularis—Gonadocorticoids
77
(Adrenal cortex)
| Mineralocorticoids
Regulate electrolyte concentrations (primarily Na+ and K+) in ECF
Importance of Na+: affects ECF volume, blood volume, blood pressure, and levels of other ions (K+, H+, HCO3− and Cl−)
Importance of K+: sets resting membrane potential of cells
78
(Adrenal cortex)
| Glucocorticoids
Influence metabolism of most cells and help us resist stressors
Keep blood glucose levels relatively constant
Maintain blood pressure by increasing action of vasoconstrictors
Glucocorticoid hormones include:
~Cortisol (hydrocortisone); only glucocorticoid in significant amounts in humans
~Cortisone
~Corticosterone
79
(Adrenal Cortex)
| Glucocorticoids regulation of secretion
Cortisol is released in response to ACTH
~ACTH released in response to corticotropin-releasing hormone (CRH)
~CRH released in response to low cortisol levels
~Increased cortisol levels inhibit ACTH and CRH through negative feedback
Cortisol secretion cycles are governed by patterns of eating and activity
Acute stress (infection, physical or emotional trauma) interrupts cortisol rhythm
CNS can override cortisol inhibition of ACTH and CRH, leading to more cortisol secretion
80
(Adrenal Cortex)
| Glucocorticoids actions
Cortisol causes increase in blood levels of glucose, fatty acids, and amino acids
Prime metabolic effect is gluconeogenesis, formation of glucose from fats and proteins
~Encourages cells to use fatty acids for fuel so glucose is “saved” for brain
Other function is to enhance vasoconstriction
~Causes rise in blood pressure to quickly distribute nutrients to cells
Excessive levels of glucocorticoids:
~Depress cartilage and bone formation
~Inhibit inflammation by decreasing release of inflammatory chemicals
~Depress immune system
~Disrupt normal cardiovascular, neural, and gastrointestinal functions
Glucocorticoid drugs can control symptoms of many inflammatory diseases (arthritis, allergies) but can also cause undesirable effects
81
Pineal Gland
Small gland hanging from roof of third ventricle
Pinealocytes secrete melatonin, derived from serotonin
Melatonin may affect:
~Timing of sexual maturation and puberty
~Day/night cycles
~Physiological processes that show rhythmic variations (body temperature, sleep, appetite)
~Production of antioxidant and detoxification molecules in cells
82
Pancreas
Triangular gland located partially behind stomach
Has both exocrine and endocrine cells
~Acinar cells (exocrine) produce enzyme-rich juice for digestion
~Pancreatic islets (islets of Langerhans) contain endocrine cells
*Alpha () cells produce glucagon (hyperglycemic hormone)
*Beta () cells produce insulin (hypoglycemic hormone)
83
Glucagon
Extremely potent hyperglycemic agent
~Triggered by decreased blood glucose levels, rising amino acid levels, or sympathetic nervous system
Raises blood glucose levels by targeting liver to:
~Break down glycogen into glucose
*Glycogenolysis
~Synthesize glucose from lactic acid and other noncarbohydrates
*Gluconeogenesis
~Release glucose into blood
84
Insulin
Secreted when blood glucose levels increase
Synthesized as proinsulin that is then modified
Insulin lowers blood glucose levels in three ways:
~Enhances membrane transport of glucose into fat and muscle cells
~Inhibits breakdown of glycogen to glucose
~Inhibits conversion of amino acids or fats to glucose
Not needed for glucose uptake in liver, kidney, or brain
Plays a role in neuronal development, learning, and memory
Binding to tyrosine kinase enzyme receptor triggers cell to increase glucose uptake
Insulin also triggers cells to:
~Catalyze oxidation of glucose for ATP production: first priority
~Polymerize glucose to form glycogen
~Convert glucose to fat (particularly in adipose tissue)
85
What are the insulin factors that influence insulin release?
Elevated blood glucose levels: primary stimulus
Rising blood levels of amino acids and fatty acids
Release of acetylcholine by parasympathetic nerve fibers
Hormones glucagon, epinephrine, growth hormone, thyroxine, glucocorticoids
Somatostatin and sympathetic nervous system inhibit insulin release
86
Diabetes Mellitus
Hyposecretion of insulin: Type 1
Hypoactivity of insulin: Type 2
When blood glucose levels remain high, person feels nauseated, leading to sympathetic response
~Fight-or-flight response acts to further increase blood glucose levels
Glycosuria: excess glucose is spilled into urine
87
What do the ovaries produce?
Estrogens
Maturation of reproductive organs
Appearance of secondary sexual characteristics
With progesterone, causes breast development and cyclic changes in uterine mucosa
Progesterone
88
Adipose cells release:
Leptin: appetite control; stimulates increased energy expenditure
Resistin: insulin antagonist
Adiponectin: enhances sensitivity to insulin
