Endocrinology & Reproduction Flashcards
(391 cards)
1
Q
Where are endocrine glands found?
A
Scattered around the body
2
Q
What do endocrine glands secrete?
A
Hormones
3
Q
Once hormones are secreted, where do they want to go?
A
Target cells
4
Q
How do hormones reach their target cells?
A
Bloodstream
5
Q
What do target cells have to recognize specific hormones?
A
Receptors
6
Q
How does a target cell recognize a hormone?
A
Through hormone-receptor binding
7
Q
What do target cells do?
A
Regulate or direct a particular bodily function
8
Q
What is the length of response produced by the endocrine system?
A
Long
9
Q
How are the 2 hormone categories determined?
A
Based on solubility
10
Q
What are the 2 categories of hormones?
A
1) Hydrophilic
2) Lipophilic
11
Q
What is special about hydrophilic hormones?
A
They can be dissolved in plasma
12
Q
What are 2 examples of hydrophilic hormones?
A
Peptide hormones (insulin and growth hormone) and Catecholamines
13
Q
What is special about lipophilic hormones?
A
They can pass through membranes and do not dissolve in plasma
14
Q
What are 2 examples of lipophilic hormones?
A
Steroid hormones and Thyroid hormone
15
Q
What 3 things does the endocrine system regulate?
A
1) Organic metabolism
2) Water and electrolyte balance
3) RBC production and use
16
Q
How does the endocrine system help the body cope?
A
By inducing adaptive change during stressful situations
17
Q
What does the endocrine system promote?
A
Smooth, sequential growth and development
18
Q
What is the function of the endocrine system that involves the ANS?
A
Control and integration of circulation as well as digestion and absorption of food
19
Q
What do tropic hormones do?
A
Regulate hormone secretion of another endocrine gland
20
Q
Does one gland produce only one hormone?
A
No, one gland can produce multiple hormones
21
Q
Does one hormone get secreted by only one gland?
A
No, more than one gland can produce and secrete the same hormone
22
Q
Does one hormone have only one type of target cell?
A
No, one hormone can have more than one type of target cell
23
Q
What about secretion varies?
A
Rate
24
Q
Is one target cell influenced by only one hormone?
A
No, a single target cell can be influenced by more than one hormone
25
What can a chemical messenger be?
A hormone or neurotransmitter
26
Do all endocrine organs only have endocrine functions?
No, many endocrine organs have other functions that are not endocrine (ex: ovaries)
27
What are 3 methods to control plasma concentration of a hormone?
1) Regulate changes in rate of hormone secretion
2) Increase rate of removal from blood by metabolic inactivation or excretion
3) Increase rate of activation or binding of hormone to plasma proteins
28
What 2 direct regulatory inputs influence secretory output of endocrine cells?
- Neural input
| - Input from another hormone
29
When does negative feedback control exist?
When output of a system counteracts a change in input
30
What does negative feedback control do to plasma concentration of a hormone?
Maintains the concentration at a given level or set-point
31
What is the purpose of neuroendocrine reflexes?
To produce a sudden increase in hormone secretion in response to a specific stimulus
32
What is an example of a neuroendocrine reflex?
Increased secretion of cortisol by the adrenal cortex during a stress response
33
What do endocrine disorders most commonly result from?
Inappropriate rates of secretion causing abnormal plasma concentrations of a hormone
34
What is hyposecretion?
Too little hormone is secreted
35
What kind of glands does the endocrine system consist of?
Ductless endocrine glands
36
What is hypersecretion?
Too much hormone is secreted
37
What is primary hyposecretion?
Too little hormone secretion due to abnormality within gland
38
What are 5 causes of primary hyposecretion?
Genetic, Dietary, Chemical or toxic, Immunologic, and Cancer
39
What is secondary hyposecretion?
Gland is normal but decreased hormone secretion due to deficiency of the glands tropic hormone
40
What are 2 causes of hypersecretion?
Tumours that ignore normal regulatory input and continuously secrete excess hormone, and Immunologic
41
What is primary hypersecretion?
Too much hormone secretion due to abnormality within gland
42
What is secondary hypersecretion?
Excessive stimulation from outside the gland causes oversecretion
43
What are the 3 ways in which hormones can influence the activity of other hormones at target cells?
1) Permissiveness
2) Synergism
3) Antagonism
44
What is permissiveness?
One hormone must present in adequate amounts for full exertion of another hormones effect
45
What is synergism?
When actions of several hormones are complimentary and the combined effect is greater than the sum of their separate effects
46
What is antagonism?
When one hormone causes loss of another hormones receptors causing reduced effectiveness of the second hormone
47
What does cholesterol act as a precursor for?
Lipophilic steroid hormones
48
How do hydrophilic hormones produce effects?
Bind to surface membrane receptors and produce effects through a second-messenger system
49
How do lipophilic hormones produce effects?
Bind to intracellular receptors and produce effects through changes in gene expression
50
What do hormone-receptor complexes recognize?
Specific sequences in DNA called Hormone-Response-Element (HRE)
51
What are 2 differences between the nervous system and endocrine system?
1) Length of response (NS = short, brief and precise; ES = long)
2) Target tissues (NS = muscles and glands; ES = every tissue in the body)
52
Location: hypothalamus
In the superior brainstem below thalamus
53
Location: pituitary gland
Inferior to hypothalamus
54
What does antidiuretic mean?
Produce less urine and store more water
55
What is the function of ADH?
Conserve body water and regulate osmotic pressure of body fluids
56
How is ADH secretion triggered?
By osmoreceptors in the brain from an increase in osmolarity due to dehydration
57
What does ADH act on and how?
Kidney cells (distal convolute tubule and medullary collecting ducts) via cell surface receptors and cAMP formation
58
What does ADH do to kidney cells?
Enhances water permeability and reabsorption
59
What is the function of oxytocin?
Stimulates contraction of smooth muscle cells
60
What does oxytocin act on?
Mammary gland and uterus
61
What stimulates oxytocin release?
Suckling and childbirth
62
What does oxytocin release stimulate?
1) Contraction of myoepithelial cells in breast to expel milk
2) Rhythmic uterine contractions
63
What is a clinical use of oxytocin?
1) To induce labour
| 2) Therapeutically postpartum to decrease bleeding
64
What does an ADH deficiency mean?
Inability to retain water
65
What are symptoms of ADH deficiency?
Excess thirst and frequent urination
66
What are 2 treatments for ADH deficiency and what do they do?
1) Clofibrate to increase ADH secretion
| 2) Chlorpropamide to increase kidney response to ADH
67
What does ADH excess mean?
Excess water retention
68
What are symptoms of excess ADH?
Headache, drowsiness, and nausea
69
What are 2 treatments for excess ADH and what do they do?
1) Butorphanol to decrease ADH secretion
| 2) Demechlocycline to decrease kidney response to ADH
70
What are the 6 hypothalamic hormones in the regulation of anterior pituitary hormones?
Corticotropin-releasing hormone (CRH); Thyrotropin-release hormone (TRH); Gonadotropin-releasing hormone (GnRH); Growth hormone-releasing hormone (GHRH); Somatostatin; Dopamine
71
What effect does corticotropin-releasing hormone have on anterior pituitary hormones?
Increases ACTH
72
What effect does thyrotropin-releasing hormone have on anterior pituitary hormones?
Increase TSH and prolactin
73
What effect does gonadotropin-releasing hormone have on anterior pituitary hormones?
Increases LH/FSH
74
What effect does growth hormone-releasing hormone have on anterior pituitary hormones?
Increases growth hormone
75
What effect does somatostatin have on anterior pituitary hormones?
Decreases growth hormone
76
What effect does dopamine have on anterior pituitary hormones?
Decreases prolactin
77
What effect does tropic hormone have on the hypothalamus?
Negative
78
What effect does tropic hormone have on the anterior pituitary?
Negative and positive
79
What effect does pituitary hormone have on the hypothalamus?
Negative
80
What does the hypothalamus secrete to the anterior pituitary?
Releasing/inhibitory factor
81
What does the anterior pituitary secrete to the endocrine gland?
Pituitary hormone
82
What does the endocrine gland secrete to the target tissue?
Tropic hormone
83
What kind of pattern do hypothalamic and pituitary hormones have and why?
Pulsatile/rhythmic secretion pattern due to fluctuation of neuronal activity
84
What is the clinical relevance of the secretion pattern for hypothalamic and pituitary hormones?
1) Maintains target organ sensitivity
| 2) If the pulsatile secretion was to be abolished, hormone secretion would be diminished
85
What is the source of growth hormone?
Somatotropes and somatommammotropes of anterior pituitary
86
What are the 5 actions of growth hormone?
Decrease insulin sensitivity; Increase lipolysis; Increase IGF-1; Increase protein synthesis; Increase epiphyseal (bone) growth
87
What are 2 actions of IGF-1?
Increase protein synthesis and increase bone growth
88
What stimulates growth hormone release?
GHRH, hypoglycemia, exercise, some amino acids, and sleep
89
What inhibits growth hormone release?
Somatostatin, negative feedback of IGF-1, and hyperglycemia
90
What is the source of prolactin?
Lactotropes and somatommammotropes of anterior pituitary
91
What are 3 actions of prolactin?
1) Promote growth and function of mammary glands to aid in milk production
2) Increase maternal behaviour
3) When [prolactin] is very high, inhibits gonadotropin secretion which decreases steroidogenesis
92
What stimulates prolactin release?
Oxytocin, TRH, VIP, and estrogen
93
What inhibits prolactin?
Dopamine
94
What can cause growth hormone excess?
Somatotropin tumor
95
What can occur from growth hormone excess?
1) Gigantism if occurs early in life
| 2) Acromegaly if occurs after body growth has stopped
96
What is acromegaly?
Excess soft tissue hyperplasia
97
What are 3 treatments for growth hormone excess?
1) Tumor removal
2) SS analogs
3) GH receptor antagonist (blocker)
98
What can cause growth hormone deficiency?
Hypothalamic or pituitary lesions
99
What can occur from growth hormone deficiency?
1) Proportional short-stature if occurs early in life
| 2) Adult hypopituitarism
100
What are symptoms of adult hypopituitarism?
Weakness; Fine wrinkling and pale skin; Loss of sex drive; Genital atrophy; Menstrual cycle cessation
101
What are 2 other causes of retarded growth in which growth hormone is not deficient?
1) GH receptor defect in target tissues
| 2) IGF-1 deficiency
102
What can treat growth hormone deficiency?
GH and IGF-1 replacement
103
What are 3 causes of prolactin excess?
1) Hyperprolactinemia
2) Dopamine receptor blockers
3) Stress, high amount of physical activity, underweight
104
What is hyperprolactinemia?
Most common form of pituitary hyperfunction caused by adenomas of lactotropes
105
What can cause the blockage of dopamine receptors?
Some psychiatric medications
106
What are the consequences of prolactin excess in females?
Anti-gonadal action which causes secondary amenorrhea, leading to infertility and galactorrhea
107
What is secondary amenorrhea?
Cessation of menstrual cycle
108
What is galactorrhea?
Inappropriate milk production
109
What are the consequences of prolactin excess for males?
Impotence, decreased sperm count and infertility
110
What is a treatment option for excess prolactin?
Dopamine agonists (such as Cabergoline or Parlodel) suppress prolactin secretion and shrink prolactinomas
111
True or false: deficiency of prolactin is rare?
True
112
What does pituitary ACTH regulate?
The adrenal gland
113
What 3 things does pituitary ACTH indirectly affect?
1) Melanin synthesis
2) Immune response
3) Decrease food intake
114
What are the 3 sections that the adrenal gland is divided into (from outermost to innermost)?
1) Zona glomerulosa
2) Zona fasciculata
3) Zona reticularis
115
Where does the mineralocorticoid pathway take place?
Zona glomerulosa
116
Where does the glucocorticoid pathway take place?
Zona fasciculata
117
Where does the androgen pathway take place?
Zona reticularis
118
What is the major form of glucocorticoid?
Cortisol
119
What is cortisol bound to and where?
Transcortin in circulation
120
Why is cortisol essential for life?
Its important direct effects on intermediary metabolism of carbs, proteins, and lipids
121
What are 4 functions of cortisol?
1) Stimulates protein breakdown to amino acids
2) Facilitates lipid breakdown in adipose tissue to fatty acids and glycerol
3) Promotes hepatic gluconeogenesis from amino acids, glycerol, and fatty acids
4) Makes glucose available to brain by inhibiting utilization by other tissues
122
At what level do anti-inflammatory and immunosuppressive effects of glucocorticoids occur?
Pharmacological levels of glucocorticoids
123
What are 3 anti-inflammatory effects of glucocorticoids?
1) Inhibit local reaction to injury
| 2) Reduce local release of degradative enzymes
3) Decrease fibroblast proliferation and collagen deposition
124
What are 3 examples of anti-inflammatory events that need glucocorticoids?
1) Rheumatoid arthritis
2) Trauma
3) Insect bites
125
What are 3 immunosuppressive effects of glucocorticoids?
1) Inhibit IL-1 production by macrophages, resulting in decreased T cell recruitment
2) Inhibit IL-2 production from T Helper cells, thus reducing T and B cell formation
3) Induce death of T cells
126
What are 2 examples of immunosuppressive events that need glucocorticoids?
1) Prevent organ/graft rejection
| 2) Manage allergic disorders
127
What should be considered for a patient on long-term use of glucocorticoids?
Impaired body's defense against infections; Loss of bone mass; Atrophy of adrenal gland; Other metabolic effects (such as hyperglycemia)
128
What is DHEA the main source of?
Angroden in females
129
What does aldosterone affect?
Kidney to regulate water and salt metabolism
130
What is the function of cortisol?
Increase metabolic fuels, such as blood glucose, amino acids, and fatty acids
131
What do glucocoorticoids exert strong negative feedback on?
Hypothalamus and anterior pituitary
132
Why does atrophy of anterior pituitary corticotropes occur in the pituitary-adreanl axis by glucocorticoids?
Because no ACTH is required
133
Why does atrophy of adrenal cortex occur in the pituitary-adreanl axis by glucocorticoids?
Lack of stimulation by ACTH
134
What is the major form of mineralocorticoids in the adrenal?
Aldosterone
135
What is the function of aldosterone?
Control body fluid volume by increasing sodium reabsorption by kidneys
136
What stimulates aldosterone secretion? (2)
Activation of RAAS in response to decreased blood pressure, low plasma sodium, and high plasma potassium; and ACTH
137
What is a major form of adrenal androgens?
DHEA (dehydroepiandrosterone)
138
Is DHEA a strong or weak androgen?
Weak
139
What is DHEA important for in males?
Nothing
140
What is DHEA important for in females?
Enhancement of pubertal growth spurt; Maintains secondary sex characteristics; Sexual desire; Some conversion to estrogen by aromatase in peripheral tissues
141
What are conditions of aldosterone excess?
Primary hyperaldosteronism (Conn's syndrome) and Secondary hyperaldosteronism
142
What are causes of aldosterone excess?
Hypersecreting tumour of zona glomerulosa or High renin-angiotensin
143
What are symptoms of aldosterone excess?
Increased sodium (hypernatremia); Decreased potassium (hypokalemia); Hypertension
144
What is a condition of cortisol excess?
Cushing's syndrome
145
What are causes of cortisol excess?
Excess CRH/ACTH; Adrenal tumour; Ectopic ACTH (lung cancer)
146
What are symptoms of cortisol excess? (5)
1) Hyperglycemia
2) Excess protein breakdown
3) Abnormal fat distribution
4) Insulin resistance
5) Decreased immune and inflammatory response
147
What is a condition of androgen excess?
Congential Adrenal Hyperplasia (CAH) / Androgenita Syndrome in females
148
What is a cause of androgen excess?
Genetic deficiency in cortisol synthetic enzymes (21- and 11-OH)
149
What are symptoms of androgen excess?
Inappropriate masculinization; Pseudohermaphroditism; Virilization in female; Pseudopuberty in boys
150
What occurs to ACTH in CAH and what does this cause?
Absence of negative feedback on ACTH; Causes increased ACTH, leading to increased DHEA, which produces a negative feedback on anterior pituitary which decreases production of LH/FSH, resulting in gonads not developing
151
What is a condition of cortisol and aldosterone deficiency?
Primary adrenal insufficiency (Addison's Disease)
152
What is the cause of cortisol and aldosterone deficiency?
Destruction or atrophy of adrenal cortex
153
What are symptoms of cortisol deficiency?
Poor response to stress; Hypoglycemia; Low metabolic activites
154
What are symptoms of aldosterone deficiency?
Increased potassium (hyperkalemia) resulting in arrhythmia, decreased heart rate, and weakness; Decreased sodium (hyponatremia) resulting in edema, headache, confusion, muscle cramp, and weakness; Hypotension
155
What is a condition of cortisol deficiency?
Secondary adrenal insufficiency
156
What is a cause of cortisol deficiency?
Insufficient ACTH caused by hypothalamic or pituitary failure
157
What are adrenal medulla catecholamines composed of?
Modified postganglionic neurons without axons
158
What do the cell bodies of adrenal medulla catecholamines produce?
Epinephrine and some norepinephrine
159
What are 3 "rules" of the actions of adrenal catecholamines?
1) Effects in target organs are mediated by alpha and beta adrenergic receptors
2) Actions of one hormone by the two classes of receptors often produce opposite effects
3) When exerted through the same type of receptor, epinephrine and norepinephrine exert similar effects
160
Is gluconeogenesis alpha or beta mediated?
Alpha
161
Is arteriolar constriction alpha or beta mediated?
Alpha
162
Is muscle contraction alpha or beta mediated?
Alpha
163
Is decreased insulin secretion alpha or beta mediated?
Alpha
164
Is increased growth hormone secretion alpha or beta mediated?
Alpha
165
Is sweating alpha or beta mediated?
Alpha
166
Is dilation of pupils alpha or beta mediated?
Alpha
167
Is glycogenolysis alpha or beta mediated?
Beta
168
Is lipolysis and ketosis alpha or beta mediated?
Beta
169
Is decreased glucose utilization alpha or beta mediated?
Beta
170
Is arteriolar dilation alpha or beta mediated?
Beta
171
Is increased cardiac contractility alpha or beta mediated?
Beta (beta 1)
172
Is increased heart rate alpha or beta mediated?
Beta
173
Is muscle relaxation alpha or beta mediated?
Beta
174
Is increased insulin secretion alpha or beta mediated?
Beta
175
Is increased renin secretion alpha or beta mediated?
Beta
176
Is increased thyroid hormone secretion alpha or beta mediated?
Beta
177
What is pheochromocytoma?
Tumors arising from chromaffin cells in the SNS, mostly in the adrenal
178
What do pheochromocytoma tumors release?
Large quantities of epinephrine and/or norepinephrine and sometimes dopamine
179
What are the consequences of pheochromocytoma?
Hypertension; Increased heart rate (palpitations); Hyperglycemia; Anxiety; Headache; Weight loss; Sweating
180
What are treatment options for pheochromocytoma?
Surgery or Alpha and beta receptor blockers
181
What is stress?
A generalized, nonspecific response of the body to any factor that overwhelms the body's compensatory abilities to maintain a state of homeostasis
182
What do stressors stimulate?
Cortisol release
183
What does the thyroid gland consist of?
2 lobes of endocrine tissue joined in the middle by isthmus (narrow portion of gland)
184
How are follicular cells arranged in the thyroid?
Into hollow spheres
185
What do follicular cells form?
A follicle
186
What is the lumen of follicular cells filled with?
Colloid
187
What is the function of colloid?
Serves as an extracellular storage site for thyroid hormone
188
What hormones do follicular cells produce in the thyroid?
1) T4/thyroxine
2) T3
- Iodine-containing and derived from tyrosine
189
What is the function of C cells in the thyroid?
Secrete peptide hormone calcitonin
190
What is the major function of the thyroid?
Synthesis, storage, and secretion of thyroid hormone
191
What are the 2 basic ingredients of thyroid hormone and how are they obtained by the body?
1) Tyrosine (synthesized by body)
| 2) Iodine (obtained from dietary intake)
192
Where does the synthesis of thyroid hormone occur?
On thyroglobulin molecules within colloid
193
How does synthesis of thyroid hormone occur?
1) Thyroglobulin is exported from follicular cells into colloid by exocytosis
2) Thyroid captures iodine from blood and transfers it into colloid by iodine pump
3) Within colloid, iodine attaches to tyrosine
4) Coupling process occurs between iodinated tyrosine molecules to form thyroid hormones
194
Where is thyroid hormone stored and for how long?
Stored in colloid until they are split off and secreted
195
How does secretion of thyroid hormone occur?
1) Follicular cells phagocytize thyroglobulin colloid
2) T3 and T4 are free to diffuse across plasma membrane and into blood
3) Most produced is T4 converted to T
196
What are 5 functions of thyroid hormone?
1) Determines basal metabolic rate
2) Influences synthesis and degradation of carbs, fat, and protein
3) Increases target-cell responsiveness to catecholamines
4) Increase heart rate
5) Aids in development of nervous system
197
What regulates the hypothalamus-pituitary-thyroid axis?
A negative-feedback system between hypothalamic TTRH, anterior pituitary TSH, and T3 and T4
198
What are causes of hypothyroidism?
1) Primary failure of thyroid gland
2) Secondary to deficinecy of TRH and/or TSH
3) Inadequate dietary supply of iodine
199
What causes cretinism?
Hypothyroidism from birth
200
What is myxedema?
Hypothyroidism is adults
201
What is treatment for hypothyroidism?
Replacement therapy (increase dietary iodine)
202
What is the most common cause of hyperthyroidism?
Graves' disease
203
What is Graves' disease?
An autoimmune disease in which the body incorrectly produces thyroid-stimulating immunoglobulins (TSI)
204
What is a physical characteristic of Graves' disease?
Exopthalmos (bulging eyes)
205
What are some treatments for hyperthyroidism?
Surgical removal of a portion of the over-secreting thyroid; administration of radioactive iodine; antithyroid drugs
206
What is a goitre?
Swelling of the neck caused by enlarged thyroid
207
Why does plasma calcium have to be closely regulated?
To prevent changes in neuromuscular excitability
208
What 5 activities does calcium play a vital role in?
1) Excitation-contraction coupling in cardiac and smooth muscle
2) Stimulus-secretion coupling
3) Maintenance of tight junctions between cells
4) Clotting of blood
5) Bone formation
209
What does hypercalcemia result in?
Reduced excitability
210
What does hypocalcemia result in?
Overexcitability of nerves and muscles
211
What can severe overexcitability cause?
Fatal spastic contractions of respiratory muscles
212
What 3 hormones regulate plasma concentration of calcium?
1) Parathyroid hormone (PTH)
2) Calcitonin
3) Vitamin D
213
What gland secretes parathyroid hormone?
Parathyroid gland
214
What is parathyroid hormone the primary regulator of?
Calcium
215
What does parathyroid do to plasma concentration of calcium and how?
Raises free plasma calcium levels by its effects on bone, kidneys, and intestines
216
Why is parathyroid hormone essential for like?
It prevents fatal consequences of hypocalcemia
217
Parathyroid facilitates activation of ______
Vitamin D
218
When is calcitonin secreted?
In response to an increase in plasma calcium concentration
219
How does calcitonin work on calcium?
Lowers plasma calciu levels by inhibiting activity of bone osteoclasts
220
When is calcitonin important?
During hypercalcemia
221
What is the function of vitamin D?
Stimulates calcium and phosphate absorption from intestine
222
How can vitamin D be made by the body?
Can be synthesized from cholesterol derivative when exposed to sunlight
223
Describe the process of activating vitamin D
Must be activated first by liver and then by kidneys before it can exert its effect on intestines
224
What are symptoms of PTH hypersecretion?
Hypercalcemia and hypophosphatemia
225
What are symptoms of PTH hyposecretion?
Hypocalcemia and hyperphosphatemia
226
What is rickets?
Vitamin D deficiency in children
227
What is osteomalacia?
Vitamin D deficiency in adults
228
What does insulin do to blood glucose?
Decreases it
229
What does glucagon do to blood glucose?
Increases it
230
What does cortisol do to blood glucose?
Increases it
231
What does epinephrine do to blood glucose?
Increases it
232
What does growth hormone do to blood glucose?
Increases it
233
What are the endocrine cells of the pancreas?
Islets of Langerhans
234
What are the exocrine cells of the pancreas?
Acini
235
What are the 4 major cell types of the pancreas?
Alpha, beta, delta, and F
236
What hormone do alpha cells of the pancreas secrete?
Glucagon
237
What hormone do beta cells of the pancreas secrete?
Insulin
238
What hormone do delta cells of the pancreas secrete?
Somatostatin
239
What hormone do F cells of the pancreas secrete?
Pancreatic polypeptide
240
What connects the A and B chains of insulin?
2 disulphide covalent bonds between cysteine residues
241
What is the function of proinsulin?
Nothing
242
What is the function of the C peptide of insulin?
Unknown
243
What cleaves the A from C chains and B from C chains in insulin?
Proprotein convertase
244
What are 4 stimulants of insulin release?
1) Sugars (glucose, mannose)
2) Amino acids (leucine)
3) Vagus nerve stimulation
4) Sulfonylureas
245
What are 3 amplifiers of glucose-induced insulin release?
1) Enteric hormones
2) Neural amplifiers (beta-adrenergic effect of catecholamines)
3) Amino acids (arginine)
246
What are 2 inhibitors of insulin release?
1) Neural (alpha-adrenergic effect of catecholamines)
| 2) Humoral (somatostatin)
247
What happens to glucose, glucagon, and insulin levels as you eat?
Glucose levels rise quickly; insulin levels rise extremely fast; glucagon levels decrease gradually
248
What 4 processes does insulin promote?
1) Glucose uptake into cells
2) Glycogen synthesis
3) Lipid synthesis
4) Protein synthesis by increasing amino acid uptake
249
Insulin is _____
Anabolic
250
Where is glucagon produced?
In Islets of Langerhans by alpha cells
251
What are 3 functions of glucagon?
1) Releases glucose
2) Stimulates gluconeogenesis (production of glucose from non-glucose sources)
3) Stimulates lipolysis
252
Glycogen breakdown to glucose in muscles is unaffected by _____, but affected by ______
Glucagon; glucocorticoids
253
What happens to lactate produced by muscles?
It goes to liver to be converted to glucose
254
What are 3 functions of glucagon with respect to lipid metabolism?
1) Increase lipolysis
2) Increase glycerol utilization
3) Decrease triglyceride synthesis
255
What is diabetes mellitus?
A syndrome of disordered metabolism with hyperglycemia caused by a deficiency of insulin and/or a reduction in effectiveness of insulin
256
What are the 2 major forms of diabetes and what occurs in each type?
1) Type 1 -- destruction of beta cells
| 2) Type 2 -- reduced sensitivity to insulin
257
What are characteristics of type 2 diabetes?
Hyperglycemia and hyperinsulinemia
258
What are 4 common chronic complications of diabetes mellitus?
1) Ophthalmologic
2) Renal
3) Neurological
4) Cardiovascular
259
What is a treatment for type 1 diabetes?
Insulin
260
What are treatments for type 2 diabetes?
Nutritional therapy (exercise, balanced diet) and pharmacological therapy
261
What are some types of pharmacological therapy for type 2 diabetes?
1) Biguanides (hypoglycemic agents that inhibit gluconeogenesis)
2) Sulfonylureas (promotes insulin secretion)
3) Thiazolidinediones (increase sensitivity to insulin)
4) Glucosidase inhibitors (inhibit digestion of complex carbs therefore reducing sugar availability)
262
What are the male and female reproductive systems designed for?
To enable union of genetic material
263
What are primary reproductive organs?
Gonads; testes in male and ovaries in female
264
What are 2 functions of mature gonads?
1) Produce gametes (sperm in male and ova in female)
| 2) Secrete sex hormones (testosterone in males and estrogen and progesterone in females)
265
What is the reproductive tract?
System of specialized ducts that transport or house gametes after they are produced
266
What do accessory sex glands do?
Empty supportive secretions into reproductive tract
267
What is an example of a female accessory sex organ?
Breasts
268
What are external genitalia?
Externally visible portions of reproductive system
269
What are secondary sexual characteristics?
External characteristics not directly involved in reproduction that distinguish males and females typically after puberty
270
What are examples of secondary sexual characteristics?
Body configuration and hair distribution
271
What are 2 functions of the male reproductive tract?
1) Produce sperm
| 2) Deliver sperm to female
272
What are the organs of the male reproductive tract?
1) Testes
2) Penis
3) Accessory sex glands
273
What are testes and where are they found?
Sperm-producing organs suspended outside abdomen in skin-covered sac (scrotum)
274
What is the function of the penis?
Deposit sperm in female
275
What are examples of male accessory sex glands?
Seminal vesicles, prostate gland, bulbourethral glands
276
What is the function of male accessory sex glands?
Secrete substances that provide bulk of semen
277
What is the pathway of the male reproductive tract?
Epididymis, ductus deferens, ejaculatory duct, urethra
278
What are 6 functions of the female reproductive tract?
1) Cyclical production of ova
2) Reception of sperm
3) Transport of sperm and ovum to common site for union
4) Maintenance of developing fetus until it can survive in outside world
5) Giving birth
6) Nourishing infant after birth with milk
279
What is the product of fertilization?
Embryo
280
When does a embryo become a fetus?
After first 2 months of intrauterine development
281
What are the organs of the female reproductive tract?
1) Oviducts
2) Uterus
3) Vagina
4) Vulva
282
What are 2 functions of oviducts?
1) Pick up ova on ovulation
| 2) Site of fertilization
283
What 2 things is the uterus responsible for?
1) Maintenance of fetus during development
| 2) Expelling fetus at end of pregnancy
284
What does the vagina connect?
Uterus to external environment
285
What is the lower portion of the vagina?
Cervix
286
Location: vaginal opening
Perineal region between urethral opening and anal opening
287
What are the labia minora and labia majora?
Skin folds that surround vaginal and urethral openings
288
What is the vulva?
Collective term for female external genitalia
289
How many chromosomes do somatic cells contain?
46
290
How many chromosomes do gametes contain?
23
291
How is gametogenesis accomplished?
Meiosis
292
How many pairs of autosomes do we have?
22
293
How many pairs of sex chromosomes do we have?
1
294
What are the 3 levels of sexual differentiation?
1) Genetic
2) Gonadal
3) Phenotypic
295
What is genetic sexual differentiation?
The combination of sex chromosomes at time of conception (either 2 X's or 1 X and 1 Y)
296
What is gonadal sexual differentiation?
Whether testes or ovaries develop
297
What determines gonadal sexual differentiation?
Presence or absence of Y chromosome
298
What is phenotypic sexual differentiation?
Apparent anatomic sex of individual
299
What determines phenotypic sexual differentiation?
Gonadal sex
300
What is a similarity between male and female external genitalia?
They develop from the same embryonic tissue
301
What does the undifferentiated external genitals in both sexes consist of?
A genital tubercle, paired urethral folds surrounding a urethral groove, and genital (labioscrotal) swellings
302
Which ducts degenerate in a female?
Wolffian ducts, leaving Mullerian ducts
303
Which ducts degenerate in a male?
Mullerian ducts, leaving Wolffian ducts
304
Why are testes found in the scrotum?
This location provides a cooler environment essential for spermaogenesis
305
Where is testosterone produced?
In Leydig cells of the testes that lie in connective tissue between seminiferous tubules
306
What does spermatogenesis begin with?
A spermatogonium
307
What is the final product of spermatogenesis?
Many spermatozoa
308
What are the 4 parts of a spermatozoan?
1) Head that contains the nucleus
2) Acrozome that caps the tip of the head; used to penetrate ovum
3) Midpiece which contains mitochondria
4) Tail which provides motility
309
What are 6 functions of Sertoli cell in the seminiferous tubules?
1) Form blood-testes barrier
2) Provide nourishment
3) Phagocytic
4) Secrete seminiferous tubule fluid which flushes released sperm from tubule into epididymis for storage and additional processing
5) Secrete androgen-binding protein
6) Site of action to control spermatogenesis
310
What are 3 functions of the epididymis and ductus deferens?
1) Store and concentrate sperm
2) Increase sperm motility and fertility prior to ejaculation
3) Mix sperm with secretions from accessory glands during ejaculation
311
What does the seminal vesicle contribute to semen?
Fructose for energy and prostaglandins
312
What does the prostate gland contribute to semen?
Alkaline fluid that neutralizes acidic vaginal secretions as well as clotting enzymes and fibrinolysin
313
What do bulbourethral glands contribute to semen?
Lubricating mucus
314
What 2 hormones control the testes?
Luteinizing hormone (LH) and follicle-stimulating hormone (FSH)
315
What hormone does LH control?
Testosterone
316
Where are LH and FSH secreteed from?
Anterior pituitary
317
What stimulates LH and FSH secretion?
Gonadotropin-releasing hormone
318
What is the predominant negative-feedback effect of testosterone?
To decrease gonadotropin-releasing hormone (GnRH) release by acting on the hypothalamus, thus indirectly decreasing LH and FSH release by the anterior pituitary
319
What is testosterone?
A steroid hormone derived from a cholesterol precursor molecule
320
What are the 5 categories of testosterone effects?
1) Reproductive system before birth
2) Sex-specific tissues after birth
3) Other reproductive-related effects
4) Secondary sexual characteristics
5) Non-reproductive actions
321
What are 3 common disorders of the male reproductive tract?
1) Benign Prostatic Hyperplasia (BPH)
2) Prostate cancer
3) Erectile Dysfunction (ED)
322
What is benign prostatic hyperplasia and what causes it?
Enlargement of prostate gland caused by growth of stromal and epithelial components
323
What are symptoms of BPH?
Urine retention; frequent voiding; changes in bladder structure and function
324
What are treatments for BPH?
Surgical removal of tissue; inhibition of prostate cell growth; block muscle contraction
325
What is the most common cancer in men?
Prostate cancer
326
What are causes of prostate cancer?
Age; genetic predisposition
327
What kind of prostate tumours are the hardest to treat?
Recurrent hormone-independent tumours
328
What is erectile dysfunction?
Age-related decline in ability to sustain an erection
329
How does Viagra (and similar drugs) work to sustain an erection?
Inhibit cGMP loss and decrease blood flow from penis
330
What are 4 functions of estrogen in females?
1) Ova maturation and release
2) Establishment of female secondary sex characteristics
3) Transport of sperm from vagina to fertilization site
4) Breast development
331
What are 2 functions of progesterone in females?
1) Preparing suitable environment for nourishing and sustaining a developing embryo
2) Contributes to breasts' ability to produce milk
332
What are oogonia?
Undifferentiated primordial germ cells in fetal ovaries
333
What happens to oogonia in the first part of fetal life and what is produced?
They begin early steps of first meiotic division but do not complete it; now become primary oocytes
334
Are primary oocytes haploid or diploid?
Diploid
335
When do primary oocytes complete their first meiotic division and what is produced?
Just before ovulation; produces first polar body and secondary oocytes
336
What happens to secondary oocytes?
They become fertilized
337
What does sperm entry into the secondary oocyte trigger and what does it produce?
Second meiotic division; produces secondary polar body and mature ovum
338
What normally interrupts the ovarian cycle?
Pregnancy
339
When is the ovarian finally terminated?
Menopause
340
What is the first half of the ovarian cycle known as?
Follicular phase
341
What is the second half of the ovarian cycle known as?
Luteal phase
342
What occurs during the follicular phase?
1) Granulosa cells of some primary follicles grow rapidly
2) Oocyte inside each follicle enlarges
3) Theca cells in follicle secrete estrogen
4) Rapid follicular growth
343
What happens to a follicle during ovulation?
Follicle ruptures and releases oocyte from ovary
344
What happens to an oocyte during ovulation?
It is released by the follicle into the peritoneal space, makes its way to the oviduct where it may or may not be fertilized
345
What happens to the follicle after ovulation?
The remaining granulosa cells rearrange into corpus luteum
346
What do the corpus luteum do?
Produces estrogen and progesterone at high levels for 14 days
347
What happens to the corpus luteum if the woman doesn't become pregnant?
It disintegrates
348
What happens to FSH during the follicular phase?
FSH rises and signals ovarian follicle to secrete more estrogen; this rise in estrogen feeds back to inhibit FSH secretion
349
What happens to LH during the follicular phase?
It rises and peaks mid-cycle, triggering ovulation and rupture of dominant follicle
350
What does progesterone output do to other hormones?
Inhibits release of FSH and LH
351
What happens to the corpus luteum when there is low LH?
It disintegrates
352
What can LH turn on?
Steroidogenesis
353
What does LH secretion trigger?
Ovulation and subsequent luteinization of the ruptured follicle
354
What are the 4 major changes in the follicle caused by LH increase?
1) Halts estrogen synthesis
2) Reinitiates meiosis in the oocyte of the developing follicle
3) Triggers production of locally acting prostaglandins
4) Differentiation of follicular cells into luteal cells
355
What hormone maintains the corpus luteum?
LH
356
What is the most abundant hormonal product of the corpus lutuem?
Progesterone
357
What are the 3 phases of the uterine cycle?
1) Menstrual phase
2) Proliferative phase
3) Secretory/progestational phase
358
What occurs in the menstrual phase?
Discharge of blood and endometrial debris from vagina
359
What part of the ovarian cycle does the menstrual phase of the uterine cycle coincide with?
End of luteal phase and beginning of follicular phase
360
What part of the ovarian cycle does the proliferative phase of the uterine cycle coincide with and why?
Last portion of follicular phase; peak estrogen levels trigger LH surge responsible for ovulation
361
What happens in the proliferative phase?
Endometrium starts to repair itself and proliferate under influence of estrogen from newly growing follicles
362
How long does the proliferative phase last?
From end of menstruation to ovulation
363
When does the uterus enter the secretory phase?
After ovulation when new corpus luteum is formed
364
What does progesterone do to endometrium?
Converts it to highly vascularized, glycogen-filled tissue
365
What does loss of estrogen primarily affect?
Skeleton and cardiovascular systems
366
What is the climacteric?
Period of transition into menopause
367
Where does fertilization occur?
Upper third of oviduct (ampulla)
368
When MUST fertilization occur?
24 hours after ovulation
369
What does a blastocyst do?
Implants in endometrial lining by means of enzymes released by trophoblasts
370
What do enzymes do to the endometrial tissue?
Digest and carve a hole in it; also release nutrients from endometrial cells for embryo to use
371
When does the placenta form?
After implantation
372
What hormones does the placenta secrete?
Human chorionic gonadotropin, estrogen, and progesterone
373
Why is human chorionic gonadotropin secreted by the placenta?
Maintains corpus luteum until placenta takes over its function in the last 2 trimesters; also stimulates placenta to maintain adequate estrogen and progesterone
374
Why are estrogen and progesterone secreted by the placenta?
Essential for normal pregnancy
375
True or false: it is not normal for pregnant women to become insulin resistant
False
376
What happens once the placenta is delivered?
Estrogen and progesterone levels plummet allowing for lactation
377
What is parturition?
Labour and delivery
378
What does the pressure of the fetus against the cervix cause?
Increase in oxytocin secretion
379
What is the role of oxytocin in parturition?
1) Cause stronger contractions
| 2) Progressively increase positive-feedback cycle until delivery is complete
380
What prepares the breasts for lactation?
Placental estrogen and progesterone promote development of ducts and alveoli in mammary glands; prolactin stimulates synthesis of enzymes essential for milk production
381
What initiates lactation?
Withdrawal of placental steroids at parturition
382
How is lactation sustained?
Suckling
383
What does suckling trigger and what does this cause?
Release of oxytocin and prolactin; oxytocin causes milk ejection by stimulating alveoli to squeeze secreted milk out through ducts and prolactin stimulates secretion of more milk to replace ejected milk
384
What can happen when prolactin is high and a woman isn't pregnant?
Pause in menstrual cycle, hence why breastfeeding mothers don't go back to menstruating until their baby is weaned
385
What is amenorrhea?
No menstrual cycle
386
What are 3 causes of amenorrhea?
1) Pregnancy
2) Menopause
3) Stress-induced down regulation of gonadotropins
387
What are symptoms of polycystic ovarian syndrome?
1) Hirsutism (abnormal facial hair growth)
2) Amenorrhea
3) Infertility
388
True or false: polycystic ovarian syndrome is obesity associated
True
389
What is endometriosis?
Ectopic endometrial tissue in the abdomen
390
What is a symptom of endometriosis and why?
Painful menstrual cycle because endometrial tissue in the abdomen is subject to same endocrine cycles as uterus (expansion, vascularization, and sloughing)
391
What is a symptom of gestational diabetes?
Fetal macrosomia (high fetal insulin and growth)
