Endocrine System Flashcards
(130 cards)
1
Q
1) How are the nervous system and endocrine system similar?
A) Effects of both the nervous system and the endocrine system are immediate and short-lasting.
B) The nervous system works antagonistically to the endocrine system to achieve homeostasis.
C) Cells of both the nervous system and the endocrine system release chemicals to communicate with cells.
D) Both the nervous system and the endocrine system operate over a series of neurons to directly affect target cells.
A
C) Cells of both the nervous system and the endocrine system release chemicals to communicate with cells.
2
Q
2) What do paracrine cells target? A) cells using neurotransmitters B) nearby but different types of cells C) distant tissues D) the same cell or cell type
A
B) nearby but different types of cells
3
Q
What is a major function of the endocrine system?
A) The endocrine system communicates directly with target cells through the use of neurotransmitters.
B) The endocrine system releases hormones into the bloodstream to reach receptors on target cells.
C) The endocrine system produces immediate, short-lasting effects.
D) The endocrine system secretes products into ducts that lead to body surfaces or cavities.
A
C. The endocrine system releases hormones into the bloodstream to reach receptors on target cells.
4
Q
Which of the following is a primary endocrine organ? A) thyroid gland B) heart C) testes D) pineal gland
A
A. thyroid gland
5
Q
5) Chemical messengers released by endocrine glands to regulate some functions of other cells are known as: A) electrolytes. B) neurotransmitters. C) antibodies. D) hormones.
A
D. hormones.
6
Q
Target cells make more receptors for a particular hormone when the level of that hormone declines in the blood stream. This process is known as: A) synergism. B) the second-messenger system. C) downregulation. D) upregulation.
A
D. upregulation.
7
Q
7) All target cells: A) have receptors to which hormones bind. B) are found in the blood. C) secrete hormones. D) produce their own hormones.
A
A. have receptors to which hormones bind.
8
Q
8) What type of hormone usually travels in the blood plasma bound to a protein? A) hydrophilic hormones B) free hormones C) hydrophobic hormones D) neurotransmitters
A
C. hydrophobic hormones
9
Q
9) What type of hormone can cross the plasma membrane to bind to a receptor in the cytosol or nucleus? A) hydrophilic hormones B) protein hormones C) hydrophobic hormones D) amine hormones
A
C) hydrophobic hormones
10
Q
10) What type of hormone is made from cholesterol? A) protein hormone
B) amine hormone
C) steroid hormone
D) peptide hormone
A
C. steroid hormone
11
Q
What often serves as the second messenger when a hydrophilic amino-acid based hormone binds its receptor? A) cAMP B) G-protein C) protein kinase D) adenylate cyclase
A
A. cAMP
12
Q
12) Upon binding to a receptor to form a hormone-receptor complex, steroid hormones may cause: A) the formation of cAMP. B) the activation of adenylate cyclase. C) an increase in protein synthesis. D) the activation of protein kinases.
A
C. an increase in protein synthesis.
13
Q
13) Increasing levels of blood glucose stimulate the release of insulin. This type of stimulation is known as: A) positive stimulation. B) neural stimulation. C) hormonal stimulation. D) humoral stimulation.
A
D. humoral stimulation.
14
Q
14) Endocrine cells that increase hormone secretion in response to other hormones are controlled by: A) positive stimuli. B) humoral stimuli. C) hormonal stimuli. D) neural stimuli.
A
C. hormonal stimuli.
15
Q
15) When blood glucose levels increase, a hormone called insulin is released from endocrine cells in the pancreas. The role of insulin is to return blood glucose levels to normal. Which part of this negative feedback loop is the stimulus? A) blood glucose levels return to normal B) pancreas C) increasing blood glucose levels D) insulin
A
C. increasing blood glucose levels
16
Q
16) Hormones that act on the same target cells yet have opposite effects are said to be: A) synergists. B) hydrophilic hormones. C) antagonists. D) neurohormones.
A
C. antagonists.
17
Q
17) With which gland does the hypothalamus have a close anatomical and physiological relationship? A) pineal gland B) adrenal gland C) thyroid gland D) pituitary gland
A
D. pituitary gland
18
Q
18) What connects the hypothalamus and pituitary gland? A) vermis
B) isthmus
C) infundibulum
D) medulla oblongata
A
C. infundibulum
19
Q
19) Hormones that control hormone secretion from other glands are known as: A) trophic hormones. B) steroid hormones. C) tropic hormones. D) growth hormones.
A
C. tropic hormones
20
Q
20) What type of tissue makes up the adenohypophysis, or anterior pituitary gland? A) glandular epithelium B) loose adipose connective tissue C) nervous tissue D) dense elastic connective tissue
A
A. glandular epithelium
21
Q
21) What is delivered over the hypothalamic-hypophyseal portal system? A) trophic hormones B) tropic hormones C) releasing and inhibiting hormones D) stimulating hormones
A
C) releasing and inhibiting hormones
22
Q
22) What hormones are released by the posterior pituitary?
A) No hormones are made by the posterior pituitary.
B) antidiuretic hormone (ADH) and oxytocin
C) releasing and inhibiting hormones
D) stimulating hormones
A
B. antidiuretic hormone (ADH) and oxytocin
23
Q
23) Where is antidiuretic hormone (ADH, or vasopressin) made? A) thyroid gland B) posterior pituitary C) anterior pituitary D) hypothalamus
A
D. hypothalamus
24
Q
24) What is the primary effect of antidiuretic hormone (ADH, or vasopressin)? A) sodium retention by the kidneys
B) water retention by the kidneys
C) increases urine production by the kidneys
D) blood glucose regulation
A
B. water retention by the kidneys
25
25) What stimulates the release of antidiuretic hormone (ADH, or vasopressin)?
A) increasing blood pressure
B) increasing solute concentration of the blood
C) increasing solute concentration of the urine
D) increasing blood glucose levels in the blood
B. increasing solute concentration of the blood
26
```
26) Which of the following organs contains target cells for oxytocin?
A) kidneys
B) lungs
C) mammary glands
D) bones
```
C. mammary glands
27
27) Which hormone controls the milk-let-down reflex? A) antidiuretic hormone (ADH, or vasopressin)
B) oxytocin
C) prolactin
D) gonadotropins
B. oxytocin
28
```
28) Where are releasing and inhibiting hormones made?
A) thyroid gland
B) posterior pituitary (neurohypophysis)
C) hypothalamus
D) anterior pituitary (adenohypophysis)
```
C. hypothalamus
29
```
29) What does thyrotropin-releasing hormone (TRH) target?
A) anterior pituitary (adenohypophysis)
B) hypothalamus
C) posterior pituitary (neurohypophysis)
D) thyroid gland
```
A. anterior pituitary (adenohypophysis)
30
```
What does thyroid-stimulating hormone (TSH, or thyrotropin) target?
A) anterior pituitary (adenohypophysis)
B) posterior pituitary (neurohypophysis)
C) hypothalamus
D) thyroid gland
```
D. thyroid gland
31
```
Which hormone stimulates the synthesis of steroid hormones by the adrenal gland?
A) prolactin-inhibiting factor
B) thyrotropin-releasing hormone (TRH)
C) adrenocorticotropic hormone (ACTH)
D) corticotropin-releasing hormone (CRH)
```
C. adrenocorticotropic hormone (ACTH)
32
```
Which of the following is a gonadotropin?
A) adrenocorticotropic hormone (ACTH)
B) thyrotropin-releasing hormone (TRH)
C) follicle-stimulating hormone (FSH)
D) corticotropin-releasing hormone (CRH)
```
C. follicle-stimulating hormone (FSH)
33
A short-term effect of growth hormone is:
A) the stimulation of glucose uptake by cells.
B) protein synthesis.
C) the production of insulin-like growth factor (IGF).
D) fat breakdown.
D. fat breakdown.
34
When growth hormone levels are low, which hormone stimulates its release?
A) somatotropin
B) growth hormone-releasing hormone (GHRH)
C) prolactin-releasing hormone (PRH)
D) somatostatin
B. growth hormone-releasing hormone (GHRH)
35
```
Hypersecretion of growth hormone after the epiphyseal plate closes causes a disorder known as:
A) gigantism.
B) acromegaly.
C) pituitary dwarfism.
D) congenital hypothyroidism.
```
B. acromegaly.
36
```
Which of the following glands is located in the anterior neck, just superficial to the larynx?
A) pancreas
B) thymus
C) thyroid gland
D) pituitary gland
```
C. thyroid gland
37
```
What hormone is made by the parafollicular cells of the thyroid gland?
A) triiodothyronine (T3)
B) thyroxine (T4)
C) calcitonin
D) parathyroid hormone (PTH)
```
C. calcitonin
38
Which of the following is NOT a main effect of the thyroid hormones?
A) promotion of growth and development
B) regulation of blood calcium levels
C) synergism with the sympathetic nervous system
D) regulation of the metabolic rate and thermoregulation
B. regulation of blood calcium levels
39
```
Thermoregulation is the responsibility of:
A) thyroid hormones.
B) thyroid-stimulating hormone (TSH).
C) parathyroid hormone (PTH).
D) calcitonin.
```
A. thyroid hormones.
40
```
What element is necessary for the production of triiodothyronine (T3) and thyroxine (T4)?
A) magnesium
B) potassium
C) calcium
D) iodine
```
D. iodine
41
If the thyroid gland is unable to produce iodinated thyroglobulin, what is the effect on hormone production?
A) Triiodothyronine (T3) and thyroxine (T4) production continues uninterrupted.
B) Excess triiodothyronine (T3) and thyroxine (T4) hormones are made.
C) Less triiodothyronine (T3) and thyroxine (T4) hormones are made.
D) Less thyroid-stimulating hormone (TSH) is made.
C. less triiodothyronine (T3) and thyroxine (T4) hormones are made.
42
Place the following hormones in the correct order of their control, from first tier to third tier.
A) thyrotropin-releasing hormone (TRH), thyroid-stimulating hormone (TSH), production of T3 and T4
B) thyroid-stimulating hormone (TSH), production of T3 and T4, thyrotropin-releasing hormone (TRH)
C) thyroid-stimulating hormone (TSH), thyrotropin-releasing hormone (TRH), production of T3 and T4
D) thyrotropin-releasing hormone (TRH), production of T3 and T4, thyroid-stimulating hormone
(TSH)
A) thyrotropin-releasing hormone (TRH), thyroid-stimulating hormone (TSH), production of T3 and T4
43
```
What is NOT a symptom of hyperthyroidism?
A) heat intolerance
B) increased blood pressure
C) slow heart rate
D) weight loss
```
C. slow heart rate
44
```
44) Edna complains of weight gain, cold intolerance, and low blood pressure. What disorder do her symptoms match?
A) Graves' disease
B) hyperthyroidism
C) exophthalmos
D) hypothyroidism
```
D) hypothyroidism
45
```
45) Which of the following accompanies Hashimoto's thyroiditis?
A) fast heart rate
B) weight gain
C) heat intolerance
D) exophthalmos
```
B) weight gain
46
46) Under normal conditions, what is the response to an increase in thyrotropin-releasing hormone (TRH)?
A) increase in growth hormone production
B) increase in thyroid-stimulating hormone (TSH) production
C) decrease in triiodothyronine (T3) production
D) decrease in thyroxine (T4) production
B) increase in thyroid-stimulating hormone (TSH) production
47
```
47) What stimulates the release of parathyroid hormone (PTH)?
A) hypercalcemia
B) cold temperatures
C) hypocalcemia
D) low basal metabolic rate
```
C) hypocalcemia
48
48) What is NOT an effect of parathyroid hormone (PTH)?
A) increased release of calcium ions from bone
B) increased osteoblast activity
C) increased absorption of calcium ions by the small intestine
D) increased reabsorption of calcium ions from fluid in the kidneys
B) increased osteoblast activity
49
```
49) Harrie has fragile bones that easily fracture. Which hormone should be checked for normal levels?
A) triiodothyronine (T3)
B) thyroxine (T4)
C) thyroid-stimulating hormone (TSH)
D) parathyroid hormone (PTH)
```
D) parathyroid hormone (PTH)
50
```
50) What neurohormones are released from the adrenal medulla?
A) corticosteroids
B) catecholamines
C) androgenic steroids
D) glucocorticoids
```
B) catecholamines
51
51) From superficial to deep, the three layers of the adrenal cortex are:
A) zona glomerulosa, zona reticularis, zona fasciculata.
B) zona glomerulosa, zona fasciculata, zona medullaris.
C) zona fasciculata, zona intermedius, zona glomerulosa.
D) zona glomerulosa, zona fasciculata, zona reticularis.
D) zona glomerulosa, zona fasciculata, zona reticularis.
52
```
52) What hormones are produced by zona glomerulosa of the adrenal cortex?
A) neurohormones
B) glucocorticoids
C) androgenic steroids
D) mineralocorticoids
```
D) mineralocorticoids
53
```
53) Classify aldosterone to the appropriate group of hormones.
A) androgenic steroid
B) mineralocorticoid
C) catecholamine
D) glucocorticoid
```
B) mineralocorticoid
54
```
54) Aldosterone regulates:
A) blood calcium ion levels.
B) blood glucose levels.
C) blood iodide ion levels.
D) extracellular sodium and potassium ion levels.
```
D) extracellular sodium and potassium ion levels.
55
```
55) What is NOT a primary effect of aldosterone?
A) maintaining blood pressure
B) maintaining blood glucose
C) regulating extracellular fluid volume
D) maintaining acid-base balance
```
B) maintaining blood glucose
56
```
56) Some potassium-sparing diuretics increase urination without the loss of potassium by working against receptors for:
A) cortisol.
B) aldosterone.
C) adrenocorticotropic hormone (ACTH).
D) glucocorticoids.
```
B) aldosterone.
57
```
57) Avery has high blood pressure and hypernatremia (excess blood sodium ion concentration). The hypersecretion of which hormone could lead to his condition?
A) calcitonin
B) insulin
C) aldosterone
D) glucagon
```
C) aldosterone
58
```
58) What is NOT a primary target tissue of cortisol?
A) liver tissue
B) muscle tissue
C) adipose tissue
D) nervous tissue
```
D) nervous tissue
59
59) What first tier hormone stimulates cortisol production?
A) somatostatin
B) corticotropin-releasing hormone (CRH)
C) thyrotropin-releasing hormone (TRH)
D) growth hormone-releasing hormone (GHRH)
B) corticotropin-releasing hormone (CRH)
60
```
60) Excess cortisol could result in:
A) increased parasympathetic nervous system activation.
B) high blood glucose levels.
C) low blood pressure.
D) an alkaline blood pH.
```
B) high blood glucose levels.
61
```
61) Which hormone acts as a potent anti-inflammatory agent?
A) cortisol
B) epinephrine
C) aldosterone
D) insulin
```
A) cortisol
62
```
62) Which hormone promotes gluconeogenesis as a way to increase blood glucose levels?
A) melatonin
B) insulin
C) aldosterone
D) cortisol
```
D) cortisol
63
```
63) Cushing's disease results from:
A) hyposecretion of epinephrine.
B) hypersecretion of cortisol.
C) hyposecretion of insulin.
D) hypersecretion of aldosterone.
```
B) hypersecretion of cortisol.
64
```
64) Hyposecretion of both aldosterone and cortisol results in:
A) Hashimoto's thyroiditis.
B) Graves' disease.
C) Cushing's disease.
D) Addison's disease.
```
D) Addison's disease.
65
```
65) Which of the following is NOT an effect of epinephrine?
A) increased heart rate
B) dilated bronchioles
C) constricted blood vessels
D) increased digestive functions
```
D) increased digestive functions
66
```
66) The effects of norepinephrine and epinephrine have nearly the same effects as the neurotransmitters of the:
A) afferent nervous system.
B) parasympathetic nervous system.
C) somatic nervous system.
D) sympathetic nervous system.
```
D) sympathetic nervous system.
67
67) Which hormones of the HPA axis stimulate the synthesis of epinephrine by chromaffin cells?
A) gonadotropin-releasing hormone (GnRH)
B) growth hormone-releasing hormone (GHRH)
C) thyrotropin-releasing hormone (TRH)
D) adrenocorticotropic hormone (ACTH)
D) adrenocorticotropic hormone (ACTH)
68
```
68) Which pancreatic cells release insulin and glucagon?
A) pancreatic islets
B) acinar cells
C) chief cells
D) chromaffin cells
```
A) pancreatic islets
69
69) What is the main function of glucagon?
A) regulate blood pressure
B) regulate sodium and potassium ion levels
C) lower blood glucose levels
D) raise blood glucose levels
D) raise blood glucose levels
70
```
70) Glucagon operates under:
A) neurohormonal stimulation.
B) humoral stimulation.
C) neural stimulation.
D) hormonal stimulation.
```
B) humoral stimulation.
71
```
71) Which hormone lowers blood glucose levels?
A) glucagon
B) cortisol
C) growth hormone
D) insulin
```
D) insulin
72
72) What is NOT a responsibility of insulin?
A) gluconeogenesis and glycogenolysis
B) promotion of satiety
C) glycogen synthesis by the liver
D) synthesis of fats from carbohydrates and lipids
A) gluconeogenesis and glycogenolysis
73
```
73) What might accompany an overdose of insulin?
A) hypoglycemia
B) polyuria
C) hyperglycemia
D) ketoacidosis
```
A) hypoglycemia
74
```
74) Glucosuria and ketonuria are characteristic of:
A) Type I diabetes mellitus.
B) Hashimoto's thyroiditis.
C) Type II diabetes mellitus.
D) diabetes insipidus.
```
A) Type I diabetes mellitus.
75
```
75) Type I diabetes mellitus is caused by a lack of:
A) aldosterone.
B) antidiuretic hormone (ADH).
C) glucagon.
D) insulin.
```
D) insulin.
76
```
76) What hormone is the primary antagonist of glucagon?
A) thyroid hormone
B) growth hormone
C) insulin
D) cortisol
```
C) insulin
77
```
77) Melatonin is produced by the:
A) pineal gland.
B) kidneys.
C) adrenal glands.
D) heart.
```
A) pineal gland.
78
```
78) What stimulates melatonin production?
A) increasing blood glucose levels
B) light and dark cycles
C) immune system
D) increasing blood pressure
```
B) light and dark cycles
79
```
79) Thymosin and thymopoietin assist in the maturation of:
A) B lymphocytes.
B) alpha cells.
C) T lymphocytes.
D) chief cells.
```
C) T lymphocytes.
80
80) High levels of testosterone inhibit the release of:
A) corticotropin-releasing hormone (CRH).
B) growth hormone-releasing hormone (GHRH).
C) thyrotropin-releasing hormone (TRH).
D) gonadotropin-releasing hormone (GnRH).
D) gonadotropin-releasing hormone (GnRH).
81
```
81) Testosterone is primarily produced by the:
A) hypothalamus.
B) anterior pituitary.
C) posterior pituitary.
D) testes.
```
D) testes.
82
```
82) Secondary sex characteristics of females are stimulated by:
A) aldosterone.
B) androgens.
C) testosterone.
D) estrogens.
```
D) estrogens.
83
```
83) What hormone is produced by adipocytes to regulate satiety, a feeling of fullness after eating?
A) erythropoietin (EPO)
B) calcitriol
C) leptin
D) atrial natriuretic peptide (ANP)
```
C) leptin
84
```
84) Atrial natriuretic peptide (ANP) promotes:
A) decreased urination.
B) water retention.
C) increased blood pressure.
D) vasodilation.
```
D) vasodilation.
85
```
85) What is the target tissue of erythropoietin (EPO)?
A) breast tissue
B) red bone marrow
C) smooth muscle tissue
D) adipocytes
```
B) red bone marrow
86
86) Which hormones work synergistically to retain water?
A) aldosterone and atrial natriuretic peptide (ANP)
B) antidiuretic hormone (ADH) and aldosterone
C) aldosterone and cortisol
D) atrial natriuretic peptide (ANP) and antidiuretic hormone (ADH)
B) antidiuretic hormone (ADH) and aldosterone
87
```
87) What hormone(s) determines the basal metabolic rate at rest when fasting?
A) catecholamines
B) thyroid hormones
C) insulin
D) glucagon
```
B) thyroid hormones
88
88) T or F: Hormones only affect certain types of cells known as target cells.
TRUE
89
89) T or F: Neuroendocrine glands, such as the adrenal medulla, consist of nervous tissue yet secrete chemicals known as neurohormones.
TRUE
90
90) T or F: In the second-messenger system, the first messenger initiates a cellular change in activity by binding a receptor in the plasma membrane.
TRUE
91
91) T or F: Endocrine cells that release hormones in response to the concentration of a certain ion or molecule in the blood or extracellular fluids are stimulated by humoral stimuli.
TRUE
92
92) T or F: The hypothalamic-hypophyseal portal system is a special blood supply that provides a connection between the hypothalamus and the pituitary gland.
TRUE
93
93) T or F: Hypersecretion of growth hormone (GH) that occurs before epiphyseal plates close results in a condition known as acromegaly.
FALSE
94
94) T or F: The follicle cells of the thyroid gland produce thyroid hormones while the parafollicular cells produce parathyroid hormone (PTH).
FALSE
95
95) T or F: Calcitonin mainly targets and inhibits the activity of osteoclasts in bone.
TRUE
96
96) T or F: Blood pressure regulation is a function of aldosterone since this hormone indirectly promotes water reabsorption.
TRUE
97
97) T or F: The most potent glucocorticoid produced by the adrenal cortex is aldosterone.
FALSE
98
98) T or F: Glucosuria, polyuria, and polydipsia are symptoms of both type I diabetes mellitus (insulin- dependent diabetes mellitus) and type II diabetes mellitus (non-insulin dependent diabetes mellitus).
TRUE
99
99) T or F: Melatonin appears to adjust the sleep phase of the sleep/wake cycle of some people.
TRUE
100
100) Identify the gland that produces and releases melatonin.
C
101
101) Identify the gland that stores hormones produced by the hypothalamus.
D
102
102) Identify the gland that produces glucocorticoids and mineralocorticoids.
K
103
103) Identify the gland that produces insulin and glucagon.
G
104
104) Identify the gland that is the target organ of thyroid-stimulating hormone.
E
105
105) Identify the neuroendocrine organ that produces and releases catecholamines.
L
106
106) Identify the part of the diencephalon that produces and releases releasing and inhibiting hormones.
B
107
107) In males, follicle-stimulating hormone (FSH) prods these organs to produce testosterone.
I
108
108) Identify the gland that produces and releases a hormone that raises blood calcium levels.
J
109
109) Identify the adenohypophysis.
A
110
110) Can hormones target all cells of the body? Explain.
No, hormones are not able to target all cells of the body. Hormones are only able to affect particular cells known as target cells. Target cells contain specific proteins, referred to as receptors, to which hormones can bind.
111
111. Discuss the two basic types of hormones, classified according to their chemical structure.
Hormones are classified as amino acid-based or steroid. Amino acid-based hormones consist of one or more amino acids and vary in size from single amino acids, to several amino acids, to complete proteins. Steroid hormones are cholesterol derivatives. While amino acid- based hormones are generally hydrophilic, all steroid hormones are hydrophobic and can interact with either intracellular or plasma membrane receptors.
112
112) Discuss the roles of the first messenger and the second messenger in the second-messenger system.
The first messenger is the hydrophilic hormone that binds to a receptor in the plasma membrane. The binding of the first messenger to the receptor activates an enzyme, which catalyzes the formation of a second messenger inside the cell. The second messenger initiates a series of events in the cell that leads to changes in its activity. The second messenger, not the first messenger, is the molecule actually initiating the cellular change in activity.
113
113) Nina is researching hormones that can stimulate and inhibit the release of growth hormone from the anterior pituitary. Predict the type of stimulation that regulates the secretion of growth hormone.
Since growth hormone is controlled by hormones that stimulate and inhibits its release, growth hormone operates under hormonal stimulation. The endocrine cells of the anterior pituitary increase or decrease their secretion of growth hormone in response to the binding of these releasing or inhibiting hormones, produced by the hypothalamus, to receptors.
114
114) Explain the three types of stimuli that regulate hormone secretion.
First, some endocrine cells increase or decrease their secretion in response to other hormones. These hormones are regulated by hormonal stimuli. Second, many endocrine cells respond to the concentration of a certain ion or molecule in the blood or extracellular fluid. These endocrine cells are regulated by humoral stimuli. Third, some cells respond to signals from the nervous system. These cells release neurohormones in response to neural stimuli.
115
115) Explain the relationship between the posterior pituitary and the hypothalamus.
The posterior pituitary makes no hormones of its own. Instead, it stores and releases two neurohormones, antidiuretic hormone (ADH, or vasopressin) and oxytocin, made by the hypothalamus. Hypothalamic axons transport ADH for storage in axon terminals in the posterior pituitary.
116
116) Explain how the hypothalamus controls the release of hormones from the anterior pituitary gland.
The hypothalamus controls many functions of the anterior pituitary through the production and release of tropic hormones that affect its secretions. These hormones are called releasing hormones and inhibiting hormones because they either stimulate or inhibit the release of hormones from the anterior pituitary. These releasing and inhibiting hormones are delivered to the anterior pituitary by the hypothalamic-hypophyseal portal system.
117
117) List the tropic hormones released by the anterior pituitary gland.
The tropic hormones of anterior pituitary include thyroid-stimulating hormone (TSH), adrenocorticotropic hormone (ACTH), prolactin (PRL), luteinizing hormone (LH), follicle- stimulating hormone (FSH), and growth hormone (GH).
118
Discuss the relationship between growth hormone (GH) and insulin-like growth factor (IGF).
Growth hormone (GH) acts on the liver and other target tissues to promote the release of insulin-like growth factor (IGF). IGF carries out the long-term effects of GH. IGF acts on nearly every cell type in the body, and triggers rapid protein synthesis and cell division. In children, IGF leads to increased longitudinal bone growth and muscle development in children. IGF also decreases blood glucose concentration by stimulating glucose uptake by cells, an action opposite to acute GH release.
119
119) Explain how thyroid hormones bind with receptors associated with their target cells.
Thyroid hormones are amino acid-based hormones, but their amino acids are nonpolar and hydrophobic. Therefore, thyroid hormones do not bind to cell-surface receptor proteins. Instead, they diffuse into target cells and then bind to intracellular receptors in the nucleus. Like steroid hormones, the thyroid hormones either activate or inactivate the transcription of certain genes.
120
120) Brenda's blood test that reveals high levels of thyroid-stimulating hormone (TSH) but low levels of triiodothyronine, or T3, and thyroxine, or T4. Determine if these results are normal or if they reveal a homeostatic imbalance. Explain to support your answer.
These blood test results are not normal; these results are consistent with a homeostatic imbalance known as hypothyroidism. With hypothyroidism, the thyroid gland is unable to produce enough T3 and T4. In response, the hypothalamus and pituitary gland continue to prod the thyroid gland through increased secretion of thyrotropin-releasing hormone (TRH) and thyroid-stimulating hormone (TSH) in an attempt to stimulate the thyroid gland. This leads to the characteristic elevated TSH and decreased T3 and T4 levels seen with hypothyroidism.
121
121) Discuss how parathyroid hormone (PTH) maintains normal blood calcium ion concentration.
Hypocalcemia occurs when the calcium ion level in the blood decreases below normal. Parathyroid hormone (PTH) is released by the chief cells of the parathyroid glands to increase blood calcium ion concentration. The main effects of PTH are to 1) increase release of calcium ions from bone by stimulating osteoclasts, 2) increase absorption of dietary calcium ions by the small intestine, and 3) increase reabsorption of calcium ions from the fluid in the kidneys.
122
122) List the three distinct zones of the adrenal cortex, from superficial to deep, and identify the group of steroid hormones produced by each.
Zona glomerulosa is the most superficial zone of the adrenal cortex. This region of cells produces mineralocorticoids. Zona fasciculata is the middle zone while the zona reticularis is the inner zone. Zona fasciculata secretes glucocorticoids; zona reticularis secretes glucocorticoids and androgenic steroids.
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23) Summarize the main functions of aldosterone.
Aldosterone has several main functions. 1) Aldosterone maintains the concentrations of extracellular sodium and potassium ions within their normal ranges, 2) aldosterone regulates extracellular fluid volume, 3) aldosterone maintains blood pressure, 4) aldosterone maintains acid-base homeostasis.
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124) Explain how cortisol helps mediate the body's response to stress.
First, cortisol increases blood glucose levels during stress by targeting the liver to convert amino acids and fats into glucose by gluconeogenesis. Second, cortisol targets muscle tissue to induce the breakdown of muscle proteins into amino acids that are sent to the liver for gluconeogenesis. Third, cortisol targets adipose tissue to break down fatty acids and release them into the blood stream. These fatty acids provide additional fuels for continued muscle activity. Finally, cortisol prevents inflammation by decreasing the levels of certain leukocytes.
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125) Discuss some of the effects of epinephrine and norepinephrine in response to a stressor.
Epinephrine and norepinephrine increase heart rate and force of contraction; dilate the bronchioles; constrict the blood vessels supplying the skin, digestive organs, and urinary organs; dilate blood vessels supplying the skeletal muscles; dilate the pupils; and decrease digestive and urinary functions.
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126) Explain how glucagon and insulin maintain normal blood glucose levels.
Beta cells of the pancreas increase insulin production when blood glucose levels increase beyond the normal range. Insulin decreases blood glucose levels by increasing glucose uptake by cells and storage of glucose, amino acids, and fats. As the blood glucose level returns to its normal range, negative feedback to beta cells decreases insulin secretion. If the blood glucose level decreases below the normal range, such as through fasting, alpha cells of the pancreas increase glucagon production. Glucagon triggers the breakdown of glycogen into glucose and the formation of new glucose through gluconeogenesis to raise blood glucose levels. As the blood glucose level returns to its normal range, negative feedback to alpha cells decreases glucagon secretion.
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127) Alcohol inhibits the release of antidiuretic hormone (ADH, or vasopressin) from the posterior pituitary. Determine why alcohol is a poor choice for rehydration when we are thirsty.
The primary effect of ADH is to increase the amount of water retained by the kidneys in response to increasing solute concentration in the blood. A lack of ADH can occur when alcohol is consumed. An insufficient amount of ADH increases the risk for dehydration since the body is unable to retain most of the water that is consumed.
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128. A young patient is short in stature, with his limbs and trunk in proportion. His mental development appears to be appropriate for his age. Determine and discuss the type of hormonal disorder he likely has.
This patient has a form of dwarfism known as pituitary dwarfism. Those with pituitary dwarfism are short in stature with limbs and the trunk in proportion. This disorder results from hyposecretion of growth hormone (GH) prior to the closure of the epiphyseal plates.
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129) Predict the impact on blood pressure for a patient who hypersecretes adrenocorticotropic hormone (ACTH).
ACTH stimulates aldosterone production and release from zona glomerulosa of the adrenal cortex. Hypersecretion of aldosterone, or hyperaldosteronism, can lead to high blood pressure. Aldosterone promotes sodium and chloride ions reabsorption in the tubule cells of the kidneys. In turn, a concentration gradient favoring the movement of water by osmosis from the fluid in those tubules to the extracellular fluid and blood is created. When aldosterone indirectly promotes water reabsorption, extracellular fluid and blood volume are increased, which in turn increases blood pressure.
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130) Lauren has type I diabetes mellitus (insulin-dependent diabetes mellitus). She has heard that her pancreas does not work at all. Did she receive correct information about her pancreas? Explain.
Lauren did not receive correct information about her pancreas since only the beta (β) cells of the pancreas are affected by type I diabetes mellitus. There are two groups of cells in the pancreas: 1) endocrine cells known as pancreatic islets, and 2) exocrine cells, called acinar cells, that release enzymes into the digestive tract. Beta (β) cells are a type of pancreatic islet cell that releases insulin. Type I diabetes mellitus is caused by the destruction of the insulin-producing β cells of the pancreas by the immune system.
