Exam #1 Flashcards
1
Q
what is a ligand?
A
hormones or neurotransmitters (chemical substances) released in response to stimuli that communicate with target cells
2
Q
what is the communication method of the nervous system compared to the endocrine system?
A
Nervous system: nerve signal causes neurotransmitter release from a neuron into a synaptic cleft
Endocrine system: secretes hormones into blood; hormones transported within the blood are distributed to target cells throughout the body.
3
Q
What is the target of stimulation of nervous system vs. endocrine system?
A
nervous system: other neurons, muscle cells and gland cells
es: any cell in the body with a receptor for the hormone
4
Q
What is the response time of the nervous system compared to the endocrine system
A
ns: rapid - milliseconds or seconds
es: slower: seconds to minutes to hours
5
Q
what is the effect of stimulation of the nervous system compared to the endocrine system?
A
ns: causes stimulation or inhibition of another neuron, contraction or relaxation of muscles, or change in secretion from glands
es: causes metabolic activity changes in target cells
6
Q
what are the range of effects for nervous system vs endocrine system?
A
ns: localized, specific effects in the body
es: widespread effects throughout body
7
Q
what is the duration of response for nervous system vs endocrine system?
A
ns: short term: milliseconds - terminates with removal of stimulus
es: long-lasting: minutes to days to weeks; may continue after stimulus is removed
8
Q
what are the functions of the endocrine system?
A
Maintaining homeostasis of blood composition and volume
Controlling reproductive activities
Regulating development, growth, and metabolism
Controlling digestive processes
9
Q
What are features of all endocrine glands?
A
ductless
extensive blood supply (so hormones can be rapidly taken by blood).
10
Q
What are the major endocrine glands?
A
pituitary gland pineal gland thyroid gland parathyroid glands adrenal glands
11
Q
what are organs which contain endocrine cells?
A
hypothalamus skin thymus heart liver stomach pancreas small intestine kidney gonads (testes and ovaries)
12
Q
what does the pineal gland secrete?
A
melatonin
13
Q
what does melatonin do?
A
makes us drowsy
14
Q
what hormone does the parathyroid produce and release?
A
parathyroid hormone (PTH)
15
Q
what does PTH do?
A
released in response to decreased blood calcium levels
16
Q
what is a reflex?
A
preprogrammed response that occurs when activated by certain stimuli
17
Q
what are the 3 types of stimulation that initiate an endocrine reflex?
A
humoral, hormonal or nervous
18
Q
what is hormonal stimulation?
A
release of a hormone in response to another hormone
19
Q
what is humoral stimulation?
A
release of a hormone in response to changes in level of nutrient of ion in the blood.
20
Q
what is nervous system stimulation?
A
release of a hormone in response to stimulation by the nervous system.
21
Q
how are hormones grouped according to chemical structure?
A
steroid hormones, protein hormones and biogenic amines
22
Q
what is a steroid hormone?
A
lipid soluble molecules synthesized from cholesterol
23
Q
what is calcitriol?
A
hormone produced by vitamin D
sometimes called steroid hormone, but really a sterol hormone - still lipid soluble
24
Q
what is a protein hormone?
A
composed of small chains of amino acids - water-soluble
25
what are biogenic amines?
modified amino acids - include epinephrine and norepinephrine and thyroid hormone
all water soluble except for thyroid hormone
26
what are local hormones?
hormones that do not circulate within blood - released from producing cells then bind to same cell or neighboring cells
27
what are eicosanoids?
primary type of local hormone made from fatty acid that comes from phospholipids within a cell's plasma membrane
synthesized through enzymatic cascade
28
What are 3 eicosaoids?
leukotrienes, prostaglandins, thromboxanes
29
what is autocrine stimulation?
when an eicosanoid initiates cellular change in the cell from which it was formed
30
what is paracrine stimulation?
when an eicosanoid initiates cellular changes in neighboring cells
31
which kind of hormones require carrier molecules?
lipid-soluble
32
what are carrier molecules?
water-soluble proteins synthesized by the liver
33
what is a bound hormone?
a hormone attached to a carrier
34
what kind of hormone can exit the blood and bind to cellular receptors of target hormones?
unbound hormones
35
why do some water-soluble hormones use carrier protein molecules?
transport carrier protein protects the hormone - prevents early destruction so prolongs the life of the hormone
36
what factors influence hormone concentration in the blood?
hormone synthesis and hormone elimination
37
how are hormones eliminated?
enzymatic degradation in liver cells or removal from the blood by excretion by the kidneys or by uptake into the target cells
38
which kind of hormone has the longer half-life?
steroid hormones have the longer half life (testosterone is 12 days), water-soluble minutes to an hour
39
how do lipid-soluble hormones (steroid hormones) interact with target cells?
1.Unbound hormones diffuse across plasma membrane
in the cell. 2.they bind to intracellular receptors (either in cytosol or nucleus) to form hormone-receptor complex 3. hormone-receptor complex binds to specific DNA sequence within the nucleus (hormone-response elements HRE's) 4. binding to DNA results in transcription of mRNA 5. tranlation of mRNA by ribosomes synthesizes specific protein.
40
can water-soluble hormones cross the plasma membrane?
no
41
how does a water-soluble hormone stimulate a target cell?
1. hormone binds to plasma membrane receptor, inducing shape change & activating receptor.
2. G protein binds to activated receptor
3. GDP is bumped off and GTP binds to G protein - activating G protein.
4. activated G protein is released from receptor, travels along inside of plasma membrane--> formation or availability of 2nd messenger
42
what are the 2 plasma membrane enzymes that protein G activates?
Adenylate cyclase and/or phospholipase C
43
describe the adenylate cyclase cascade
1. activated G protein binds to and activated plasma membrane enzyme adenylate cyclase
2. adenylate cyclase converts ATP to cAMP molecules.
3. cAMP serves as the 2nd messenger by activating protein kinase A.
44
describe phospholipase C enzyme cascade
1. activated G protein binds to and activates plasma membrane enzyme phospholipase C
2. phospholipase C splits PIP2 into 2 2nd messengers: DAG and IP3
3a. DAG activates protein kinase C
3b. IP3 increases Ca2+ in cytosol (stimulates release from endoplasmic reticulum and entry across the plasma membrane from the interstitial fluid).
3c. Ca2+ acts as 3rd messenger to activate protein kinase enzymes.
45
what organ releases glucagon?
pancreas
46
why is glucagon released?
in response to low blood glucose levels
47
where does glucagon go after it is released?
receptors in plasma membrane of liver cells - causes increase in cAMP synthesis and activation of kinase A enzymes, kinase A enzymes phosphorylate enzyme pathways that lead to release of glucose from liver cells
48
what does glucose do?
enters blood and helps return blood glucose levels to normal homeostatic range
49
what organ releases oxytocin?
posterior pituitary
50
what does oxytocin do?
binds with membrane receptors of smooth muscle cells in uterus to increase production of IP3 which increases intracellular Ca2+ and causes stronger uterine contractions to expel the baby
51
what does the intracellular enzyme cascade do?
happens after hormone binds to cell membrane receptor, then G protein, transmembrane enzyme (either adenylate cyclase or phopholipase C), 2nd messenger, and protein kinase become involved. Activated protein kinase can either stimulate or inhibit enzymatic pathways within the cell, alter cell permeability to an ion, or both.
52
what are two advantages to the signaling pathways?
1. amplifies signal at each enzymatic step
| 2. provides more places and opportunities to fine-tune and regulate the pathway activities (because it is multi-step)
53
what is up-regulation?
cells increase the number of receptors - increasing cell's sensitivity to a hormone
54
what is down-regulation?
cell decreasing the number of receptors, reducing the cell's sensitivity to a hormone.
55
what causes a cell to alter the number of hormone receptors?
hormone concentration in the blood.
developmental maturity
cell's state of activity,
different stages of the cell cycle
56
what are the 3 ways in which hormones interact?
synergistic, permissive, antagonistic
57
what is synergistic hormone interaction?
activity of one hormone reinforces the activity of another hormone
i.e. estrogen and progesterone together more powerfully influence female reproductive structures together than by themselves.
58
what is permissive hormone interaction?
activity of one hormone requires a second hormone
| i.e. prolactin is required to produce breast milk and oxytocin is required for milk ejection
59
what is antagonistic hormone interaction?
effects of one hormone oppose the effects of another hormone
i.e. glucagon (initiates cellular changes that increase blood glucose levels) and insulin(initiates cellular changes that decrease blood glucose levels).
60
What hormone does the pineal gland produce?
Melatonin
61
what is the function of melatonin?
regulates the body's circadian rhythm
62
What hormones does the hypothalamus produce?
oxytocin and antidiuretic hormone
63
what does the posterior pituitary do?
stores and releases oxytocin and antidiuretic hormone
64
what is the function of oxytocin?
uterine contractions and breast milk release
65
what is the function of antidiuretic hormone?
fluid balance
triggered by increase in blood osmolarity (too many particles in blood - means dehydrated), reduces urine production, increases water-reabsorption in the kidney
66
What does the anterior pituitary produce?
```
TP-FLAG
thyroid-stimulating hormone
prolactin
follicle-stimulating hormone
luteinizing hormone
adrenocorticotropic hormone
growth hormone
```
67
what is the function of thyroid-stimulating hormone?
stimulates the thyroid gland to release thyroid hormone
68
what is the function of prolactin?
breast milk production
69
what is the function of follicle-stimulating hormone?
development of gametes (and follicle in female)
| regulate hormone synthesis by the gonads
70
what is the function of luteinizing hormone?
development of gametes (and ovulation in female)
| regulating hormone synthesis by gonads
71
what is the function of adrenocorticotropic hormone?
stimulates adrenal cortex to produce and release corticosteroids (glucocorticoids). - like cortisol
72
what is the function of growth hormone?
stimulates cell growth and division
affects most body parts - especially those within the skeletal and muscular systems
stimulates liver to release insulin-like growth factor 1 and 2 (IGF-1 and IGF-2)
73
what hormones are produced by the thyroid gland?
thyroid hormone
| calcitonin
74
what is the function of thyroid hormone?
increases metabolism
75
what is the function of calcitonin?
decreases blood calcium levels
76
what hormones are produced by the parathyroid glands?
parathyroid hormone
77
what is the function of the parathyroid hormone?
increases blood calcium levels
78
what hormones are produced by the adrenal medulla?
catecholamines (epinephrine and norepinephrine)
79
what do catecholamines do?
prolong fight-or-flight response
80
what hormones are produced by the adrenal cortex?
mineralcorticoids (like aldosterone)
glucocorticoids (like cortisol)
gonadocorticoids (like androgens)
81
what do mineralcorticoids do?
regulate blood sodium and potassium levels
82
what do glucocorticoids do?
(cortisol)
| participate in stress response
83
what is the function of gonadocorticoids?
(androgens)
| stimulates maturation and functioning of the reproductive system
84
what hormones does the skin produce?
vitamin D - later converted to calcitriol through enzymes in the liver and kidney
85
what is the function of vitamin D (and calcitriol)?
promotes absorption of calcium from gastrointestinal tract into blood
86
what hormones are produced by the thymus?
thymosin, thymulin, thymopoietin
87
what are the functions of thymosin, thymulin, and thymopoietin?
stimulates maturation of T-lymphocytes
88
what hormones are produced by the heart?
atrial natriuretic peptide
89
what hormones are produced by the stomach?
gastrin
90
what hormones are produced by the liver?
angiotensinogen
| erythropoietin
91
what is the function of angiotensinogen?
regulates blood volume and blood pressure
92
what is the function of erythropoietin?
increases production of erythrocytes
93
what hormones does the pancreas produce?
insulin and glucagon
94
what is the function of insulin?
decreases blood glucose
95
what is the function of glucagon?
increases blood glucose
96
what hormones are produced by the small intestine?
secretin and cholecystokinin
97
what hormones are produced by the kidneys
erythropoietin
98
what hormones are produced by testes?
androgens (testosterone) and inhibin
99
what is the function of testosterone and inhibin?
stimulate maturation and function of male reproductive system
100
what hormones are produced by the ovaries?
estrogen, progesterone, inhibin
101
what are the functions of estrogen, progesterone, inhibin?
stimulate maturation and function of female reproductive system
102
OT
oxytocin
103
ADH
antidiuretic hormone
104
TSH
thyroid-stimulating hormone
105
PRL
prolactin
106
FSH
follicle-stimulating hormone
107
LH
luteinizing hormone
108
ACTH
adrenocorticotropic hormone
109
GH
growth hormone
110
TH
thyroid hormone
111
PTH
parathyroid hormone
112
ANP
atrial natriuretic peptide
113
EPO
erythropoietin
114
what is a nutrient?
organic molecules derived from foods to generate ATP
115
what forms of nutrients circulate in the blood?
simple forms: glucose, fatty acids, amino acids
116
how are glucose and fatty acid stored within cells?
as glycogen and triglycerides (more complex forms)
117
what structures help regulate nutrient blood levels?
liver, adipose connective tissue and skeletal muscle - can be used for storing nutrients when blood levels are high, can be withdrawn when blood levels are falling
118
what enzymatic pathways for nutrient processing exist in the liver?
glycogenesis, glycogenolysis, gluconeogenesis
119
what is glycogenesis?
the synthesis of glycogen from glucose obtained from the blood
120
what is glycogenolysis?
the breakdown of stored glycogen into glucose
121
what is gluconeogenesis?
production of glucose from noncarbohydrate molecules such as amino acids, fatty acids or lactate
122
do muscle cells engage in glycogenolysis?
yes, but do not release glucose into the blood. use glucose to support their own high energy needs
123
what enzymatic pathways do adipose connective tissue cells use?
lipogenesis and lipolysis
124
what is lipogenesis?
the synthesis of triglycerides for storage from fatty acids and glycerol obtained from the blood
125
what is lipolysis?
the breakdown of triglycerides into glycerol and fatty acids that are then released into the blood
126
which cells use enzymatic pathways that produce protein?
all cells - especially muscle cells
127
what is protein anabolism?
synthesis - stimulated with increased uptake of amino acids from the blood
128
what is protein catabolism?
breakdown of protein to release amino acids - usually only used for emergency purposes
129
which gland's hormone release does the hypothalamus control?
the pituitary gland
130
which glands does the hypothalamus indirectly control hormone release from?
thyroid gland, adrenal gland, liver, testes and ovaries
131
what is another name for the pituitary gland?
the hypophysis
132
what is the stem of the pituitary gland called?
the infundibulum (or infundibular stalk)
133
what is another name for the posterior pituitary?
neurohypophysis
134
what is the pars nervosa?
the rounded lobe of the posterior pituitary
135
what is the posterior pituitary composed of?
the infundibulum and the pars nervosa
136
what is in the posterior pituitary?
axons (dendrites and cell bodies of neurons are in the hypothalamus) - synaptic knobs and ends of axons are in the pars nervosa
137
what is another word for the anterior pituitary?
adenohypophysis
138
how are the anterior pituitary and the hypothalamus connected?
through direct blood pathway called hypothalamo-hypophyseal portal system (from primary plexus - capillary network on hypothalamus - to secondary plexus - capillary network on anterior pituitary)
139
does the posterior pituitary produce any hormone?
no - just stores oxytocin and antidiuretic hormone that are synthesized in hypothalamus (transported through unmyelinated axons to synaptic knobs in posterior pituitary)
140
how do hormones travel from hypothalamus to the anterior pituitary?
hormones are released into the primary plexus, then transported via the hypophyseal portal vein to the secondary plexus within the anterior pituitary. anterior pituitary then releases its hormones into the blood of the general circulation.
141
what are the hormones released by the hypothalamus called?
regulatory hormones
142
what are regulatory hormones?
molecules secreted into the blood by the hypothalamus to regulate secretion of anterior pituitary hormones.
143
what are the 2 groups of regulatory hormones?
releasing hormones (RHs) and inhibiting hormones (IHs)
144
what are releasing hormones?
stimulate production and secretion of specific anterior pituitary hormones
145
what are inhibiting hormones?
deter production and secretion of specific anterior pituitary hormones
146
What are the hormones that are synthesized and released into the hypothalamo-hypophyseal portal system from the hypothalamus?
```
Thyrotropin-releasing hormone
prolactin-releasing hormone
gonadotropin-releasing hormone
corticotropin-releasing hormone
growth hormone-releasing hormone
prolactin-inhibiting hormone
growth-inhibiting hormone
```
147
TRH
thyrotropin-releasing hormone
148
PRH
prolactin-releasing hormone
149
GnRH
Gonadotropin-releasing hormone
150
CRH
corticotropin-releasing hormone
151
GHRH
Growth hormone-releasing hormone
152
PIH
prolactin-inhibiting hormone
153
GIH
Growth-inhibiting hormone
154
what are tropic hormones?
hormones secreted by the anterior pituitary that stimulate other endocrine glands or cells to secrete other hormones
155
name the tropic hormones
```
thyroid-stimulating hormone
follicle-stimulating hormone
luteinizing hormone
adrenocorticotropic hormone
growth hormone
```
156
what is another name for thyroid stimulating hormone?
thyrotropin
157
what are gonadotropins?
follicle-stimulating hormone and luteinizing hormone
158
what is another name for adrenocorticotropic hormone?
corticotropin
159
what are the tropic effects of growth hormone?
stimulates liver to release insulin-like growth factor 1 and 2 (IGF-1 IGF-2)
160
what hormone does the anterior pituitary also release?
melanocyte-stimulating hormone (MSH)
stimulates the rate of melanin synthesis by melanocytes
little effect in humans - usually ceases prior to adulthood
161
what are 3 disorders of growth hormone secretion?
```
pituitary dwarfism (also associated with low blood-sugar)
pituitary giantism (associated with blood glucose management - diabetes)
acromegaly - excessive GH production in adulthood - increase release of glucose - diabetes
```
162
What are variable that influence the release of growth hormone releasing hormone from the hypothalamus?
age
time of day
nutrient levels in the blood
stress and exercise
163
What is one of the primary targets of GH?
hepatocytes - cells in the liver
164
what do hepatocytes do in response to growth hormone?
release insulin-like growth factor (IGF)
165
what does insulin-like growth factor do?
responsible for greater response from target cells - other than that, similar to growth hormone
166
what is the half life of growth hormone?
6-20 minutes
167
what is the half-life of insulin-like growth hormone?
20 hours
168
why the difference in half life of GH and IGH?
IGH uses carrier proteins in the blood - help protect it from destruction
169
How do bone, muscle and cells respond to GH and IGF?
increased growth
increased amino acid uptake ---> protein synthesis
stimulated mitosis
cell differentiation
170
how does liver tissue respond to GH and IGF?
increased glycogenolysis and gluconeogenesis
decreased glycogenesis
so blood glucose levels rise
171
what is diabetogenic?
rise in blood glucose as a result of GH stimulation in the liver
172
what happens to adipose connective tissue in response to GH and IGF?
increased lipolysis
decreased lipogenesis
increases level of glycerol and fatty acids in the blood
173
why does GH and IGF increase blood glucose and glycerol and fatty acids?
growth is energy dependent - need nutrient molecules for generating ATP
174
how are the release of GHRH and GH regulated?
negative feedback:
in response to increased levels of GH and IGF, hypothalamus releases growth-hormone-inhibiting hormone (GHIH) which inhibits release of GH from anterior pituitary
also GH directing inhibits its own release from the anterior pituitary.
175
what does thyroid hormone do?
increases metabolic rate and body temperature
176
what controls release of the thyroid hormone?
hypothalamus via the anterior pituitary
177
describe the microscopic view of thyroid gland
spherical structures are thyroid follicles
walls of each follicle are formed by simple cuboidal epithelial cells called follicular cells
lumen houses protein-rich fluid called colloid
follicular cells produce and release thyroid hormone
178
why is Iodine necessary?
Thyroid needs it to make thyroid hormone
179
what causes the hypothalamus to release thyrotropin-releasing hormone?
decreased blood levels of thyroid hormone, cold weather, pregnancy, high altitude, hypoglycemia and in children, decreased body temperature
180
What are the two forms of thyroid hormone?
triiodothyronine (T3) and tetraiodothyronine (thyroxine) (T4)
181
How are T3 and T4 moved around in the blood?
by carrier molecules
182
How do all cells, especially neurons, respond to increased levels of Thyroid hormone?
increased metabolic rate
| increased glucose uptake
183
how does liver tissue respond to increased levels of thyroid hormone?
increased glycogenolysis and gluconeogenesis
| decreated glycogenesis
184
how does adipose connective tissue respond to increased levels of thyroid hormone?
increased lipolysis
| decreased lipogenesis
185
how do the lungs respond to increased levels of thyroid hormone?
increased breathing rate
| helps meet increased O2 demand for aerobic cellular respiration
186
how does the heart respond to increased levels of thyroid hormone?
increased heart rate, increased force of contraction
| helps meet increased O2 demand for aerobic cellular respiration
187
What does thyroid hormone do in all cells, especially neurons?
increases protein synthesis
| stimulates the synthesis of sodium-potassium pumps in nervous tissue-->generates heat---> calorigenic effect
188
What is hyperthyroidism?
```
excessive production of TH
increased metabolic rate
weight loss
hyperactivity
heat intolerance
```
189
what is Graves' disease?
hyperthyroidism caused by loss of feedback control by the thyroid
identifying symptom is exophthalmos (bulging eyeballs)
190
what is hypothyroidism?
```
decreased production of TH
low metabolic rate
lethargy
feeling cold
weight gain
photophobia (sensitivity to light)
```
191
what is goiter?
enlargement of the thyroid - usually due to insufficient iodine
prevents thyroid from producing TH, pituitary keeps releasing TSH, and thyroid follicles and thyroid itself overgrow.
192
what is the glucose-sparing effect?
saving blood glucose for the brain by releasing glycerol and fatty acids into the blood as alternative fuel molecules (done by adipose connective tissue in response to thyroid hormone through lipolysis and inhibiting lipogenesis)
193
how is the release of thyrotropin-releasing hormone and thyroid-stimulating hormone regulated?
negative feedback - increased TH inhibits release of TRH and TSH, also causes release of growth hormone inhibiting hormone which inhibits release of TSH from anterior pituitary.
194
what are the two areas of the adrenal glands?
adrenal medulla and adrenal cortex
195
what is the inner region of the adrenal gland called?
adrenal medulla
196
what is the outer region of the adrenal glands called?
the adrenal cortex
197
what does the adrenal medulla release?
catecholamines epinephrine and norepinephrine (in response to sympathetic nervous stimulation)
198
what are the 3 regions of the adrenal cortex?
zona glomerulosa from outer to inner
zona fasciculata
zona reticularis
199
what does the zona glomerulosa look like?
thin, dense, spherical clusters of cells
| just underneath the capsule
200
what does the zona glomerulosa do?
synthesizes mineralocorticoids - aldosterone is the principal mineralocorticoid
helps regulate the composition & concentration of electrolytes in body fluids
201
what does aldosterone regulate?
ratio of Na+ and K+ by altering the amounts excreted by the kidney into the urine - stimulates Na+ retention and K+ secretion
202
what does the zona fasciculata look like?
"bundle of sticks" - middle biggest layer - parallel cords bubbly and pale
203
what does the zona fasciculata do?
synthesizes glucocorticoids - primarily cortisol and corticosterone.
204
what does the zona reticularis look like?
innermost region of the cortex - (network) narrow band of small, branching cells
205
what does the zona reticularis do?
secretes minor amounts of sex hormones called gonadocorticoids - primary one is androgen
converted to estrogen in females
206
what do glucocorticoids do?
increase nutrient levels in the blood (glucose, fatty acids and amino acids) especially in an attempt to resist stress and help repair injured or damaged tissues
207
What is the hypothalamic-pituitary-adrenal axis?
corticotropin-releasing hormone (CRH) is released from hypothalamus, adrenocorticotropic hormone (ACTH) is released from anterior pituitary, then cortisol is released from adrenal cortex
208
how does cortisol travel through the blood?
transported by carrier proteins, randombly becomes unbound from its carrier protein & exits the blood
209
what are variables that act on the hypothalamus to stimulate release of CRH - corticotropin-releasing hormone?
negative feedback by cortisol
time of day
stress
210
What is the net effect of cortisol release from the adrenal cortex?
increase of all nutrients in the blood
211
How does the liver respond to cortisol?
stimulation of gluconeogenesis (use of amino acids and fatty acids)
releasing glucose into the blood, (removing glycerol fatty acids and amino acids)
212
how does adipose connective tissue respond to cortisol?
stimulation of lipolysis and inhibition of lipogenesis
| release of glycerol fatty acids into the blood
213
how do all cells respond to cortisol?
stimulation of protein catabolism (occurs in all cells except hepatocytes)
releasing amino acids into the blood
214
what do high doses of cortisol do?
increase retention of Na+ and H2O
decrease inflammation
suppress the immune system
inhibit connective tissue repair
215
Does cortisol stimulate most cells to increase or decrease glucose uptake?
decrease = glucose-sparing effect so saves blood glucose for use in the brain
216
How is release of CRH and ACTH regulated?
negative feedback
| increasing levels of cortisol inhibit release of CRH from hypothalamus and ACTH from anterior pituitary.
217
What is the stress response - general adaptation syndrome?
1. alarm reaction (sympathetic autonomic nervous system response)
2. stage of resistance - after a few hours as glycogen in liver is depleted - regulated by endocrine system - relase of glucocorticoids (cortisol) to provide glucose to meet the increased energy demands
3. stage of exhaustion - after weeks or months as fat stores in adipose connective tissue are depleted - weakness, electrolyte imbalances (due to elevated levels of aldosterone) bad news
218
what are the pancreatic hormones?
insulin and glucagon
219
what are the major types of cells in the pancreas?
pancreatic acini and pancreatic islets
220
what is another name for pancreatic islets?
islets of Langerhans
221
what kinds of cells make up a pancreatic islet?
alpha cells (secrete glucagon) and beta cells (secrete insulin)
222
how do you tell the pancreatic islet from the acinus?
acinus are wheel shape, islets take up much less volume - more wavy and irregular looking
223
what is the primary function of the pancreas?
maintain the concentration of glucose in the blood within normal range - 70-110mg/dL
224
what usually causes insulin release from the pancreas?
food intake - increase in blood glucose
225
How does liver tissue respond to insulin?
increased glycogenesis
| decreated glycogenolysis and gluconeogenesis
226
how does adipose connective tissue respond to insulin?
increased lipogenesis
| decreased lipolysis
227
how do all cells (especially muscle) respond to insulin?
increased uptake of amino acids, which stimulate protein anabolism
228
how do most cells respond to insulin?
increased uptake of glucose by increasing glucose transport proteins in the plasma membrane
229
what is the net effect of insulin release?
decreased blood glucose (fatty acids and amino acids are also decreased in the blood).
results in both a decrease in all nutrients in the blood and in an increase in the synthesis of the storage form of these molecules within body tissues.
230
what controls glucose the release of insulin?
negative feedback - as blood glucose levels decrease, less insulin is released from the pancreas
231
what does nervous tissue depend on for cellular respiration?
glucose
232
what is the stimulus for glucagon release?
decrease in blood glucose levels
233
what cells release glucagon?
alpha cells in the pancreas
234
what is the livers response to glucagon?
increased glycogenolysis and gluconeogenesis
| decreased glycogenesis
235
what is adipose connective tissue's response to glucagon?
increased lipolysis
| decreased lipogenesis
236
what is the net effect of glucagon release?
increased blood glucose and fatty acid levels (no change in amino acids or proteins)
237
what are formed elements?
erythrocytes, leukocytes and platelets
238
What is the function of erythrocytes?
transport respiratory gases in the blood
239
what is the function of leukocytes?
to defend the body against pathogens
240
what is the function of platelets?
clot blood and prevent blood loss from damaged vessels
241
what is plasma?
fluid portion of blood - contains plasma proteins and dissolved solutes
242
what are the general functions of blood?
transportaion, regulation and protection
243
how does blood regulate body temperature?
absorbs heat from body cells, releases heat from body at surface as blood is transported through blood vessels of the skin
244
What is cushing syndrome?
excessive levels of glucocorticoid hormones
| body obesity - especially in face & buffalo hump
245
what is addison disease?
chronic shortage of glucocorticoids and sometimes mineralocorticoids
weight loss, fatigue and weakness, hypotension & darkening of the skin
246
what is adrenogenital syndrome (or androgen insensitivity syndrome or congenital adrenal hyperplasia)?
inability to synthesize corticosteroids. anterior pituitary released massive amounts of ACTH - results in intermediate hormones making testosterone-like effect-->virilization (masculinization)
247
what does diabetes mellitus mean?
sweetened with honey
248
what is diabetes mellitus
inadequate uptake of glucose from the blood
damage blood vessels - especially smaller arterioles
leading cause of retinal blindness, kidney failure & nontraumatic leg amputations
heart disease and stroke risk
249
what is type 1 diabetes?
juvenile diabetes (insulin-dependent diabetes mellitus)
absent or diminished production & release of insulin by the pancreatic islet cells
trigger can be viral infection leading to autoimmune destruction of beta cells in pancreas
daily injections of insulin
250
what is type 2 diabetes?
insulin-independent diabetes mellitus
obesity plays role
decreased insulin release from pancreatic beta cells or decreased insulin effectiveness at peripheral tissue
251
what is gestational diabetes?
latter half of pregnancy
can pose risk to fetus as well as delivery complications
resolves after giving birth, but 20%-50% chance of developing type 2 diabetes within 10 years.
252
what is hypoglycemia?
when blood glucose levels drop below 60 mg/dL
symptoms thought to occur from insufficient glucose to the brain or from activation of the sympathetic nervous system in response to low glucose levels.
253
what color is oxygen poor blood?
dark red
254
what color is oxygen rich blood?
bright red
255
what is the average volume of blood in an adult?
5L
256
how viscous is blood?
4-5 times more viscous than water
257
why is plasma concentration important?
relative concentration of solutes in plasma determines whether fluids move into or out of plasma by osmosis as blood goes through capillaries
258
what is the temperature of blood?
about 1 degree higher than body temp - so it is 38 degrees C (or 100.4 degrees F)
259
what is blood pH?
slightly alkaline 7.35-7.45
260
what does a centrifuge do to blood?
separates whole blood into erythrocytes (about 44%), buffy coat (less than 1% - the platelets and leukocytes), and plasma (about 55% water, proteins and other solutes)
261
what is a hemotocrit?
percentage of the volume of all formed elements in the blood (erythrocytes, leukocytes and platelets)
262
what kind of fluid is plasma?
extracellular (because it is body fluid found outside of cells)
similar to interstitial fluid, but protein concentration is higher in plasma than in interstitial fluid.
263
what prevents loss of fluid from the blood as it moves through the capillaries?
osmotic pressure of plasma proteins (higher concentration in blood than out of blood, so water wants to come in)
264
what is colloid osmotic pressure?
osmotic pressure exerted by plasma proteins
265
what is the composition of blood plasma?
```
water (92%)
plasma proteins (about 7%)
albumin(58% of plasma proteins)
globulins(37% of plasma proteins)
fibrinogen(4% of plasma proteins)
regulatory proteins(less than 1% of plasma proteins)
other solutes (less than 1%)
electrolytes
nutrients
respiratory gases
wastes
```
266
what is the function of albumin?
exerts osmotic force to retain fluid within the blood
contributes to blood's viscosity
responsible for some fatty acid and hormone transport
267
what is the function of globulins?
alpha-globulins transport lipids and some metal ions
beta-globulins transport iron ions and lipids in blood
gamma-globulins are antibodies that immobilize pathogens
268
what is the function of fibrinogen?
participates in blood coagulation
269
what is the function of regulatory proteins in the blood?
enzymes accelerate chemical reactions in the blood and hormones - being transported throughout the body to target cells
270
what is the function of electrolytes in the blood?
helps establish and maintain membrane potentials, maintain pH balance, and regulate osmosis
271
what is the function of nutrients in the blood?
energy source - precursor for synthesizing other molecules
272
what is the function of respiratory gases in the blood?
O2 is needed for aerobic cellular respiration, carbon dioxide is a waste produce produced by cells during this process
273
what are the function of wastes in the blood?
no function - just being transported to liver and kidneys where they can be removed
274
what is serum?
plasma with clotting proteins removed
275
what regulates sodium blood level?
aldosterone, estrogen, progesterone, glucocorticoids and atrial natruirietic peptide (ANP)
276
what regulates potassium blood levels?
Aldosterone, ANP (atrial natruirietic peptide)
277
what regulates Calcium blood levels?
parathyroid hormone, calcitriol, calcitonin
278
what regulates Hydrogen blood levels?
buffering systems - chemicals in blood, kidney and respiratory system
279
what regulates hydrogen phosphate blood levels?
parathyroid hormone
280
what is the function, lifespan and density of erythrocytes?
transport oxygen and CO2, 120 days, 4.8-5.4 million per microliter
281
what is the function, life span and density of leukocytes?
initial immune response, defend against potentially harmful substances, 12 hours (neutrophils) to years (lymphocytes), 4500-11,000 per microliter
282
what are the function, life span and density of platelets?
participate in blood clotting, 8-10 days, 150,000-400,000 per micro liter
283
what is hemopoiesis?
process of producing formed elements
284
what are hemocytoblasts?
blood stem cells - pluripotent - they can differentiate and develop into many different kinds of cells
285
What kind of lines do hemocytoblasts produce?
myeloid line and lymphoid line
286
what do myeloid stem cells produce?
erythrocytes
all leukocytes except lymphocytes (including granulocytes and monocytes) and megakaryocytes (cells that produce platelets)
287
what do lymphoid stem cells produce?
lymphocytes
288
What is erythropoiesis?
process of erythrocyte production
289
how fast are erythrocytes produced?
3 million per second
290
what controls the rate of erythrocyte production?
erythropoietin (EPO) - hormone that increases production
291
what are the dietary requirements for erythropoeisis?
iron, B vitamins and amino acids
292
what are the steps of erythropoeisis?
begins with myeloid stem cell
- > progenitor cell
- >proerythroblast (has a nucleus)
- >erythroblast (producing hemoglobin in cytoplasm)
- >normoblast (nucleus has been ejected)
- >reticulocyte (no organelles except ribosomes, but produces hemoglobin
- >mature erythrocyte (plasma membrane bag with hemoglobin
293
how long does erythropoeisis take?
about 7 days
294
what is leukopoiesis?
production of leukocytes
295
what are the 3 types of granulocytes?
neutrophils, basophils and eosinophils
296
How are granulocytes formed?
myeloid stem cell
- >progenitor cell
- >myeloblast
- >differentiates into 1 of 3 granulocytes
297
how is a monocyte formed?
myeloid stem cell
- >progenitor cell
- >monoblast
- >promonocyte
- >monocyte
298
what is thrombopoiesis?
production of platelets
299
How are platelets formed?
myeloid stem cell
- >megakaryoblast
- >under influence of thrombopoietin, forms megakaryocyte
- >produces thousands of platelets
300
what is the structure of a erythrocyte?
plasma membrane with 280 million hemoglobin molecules
301
what do erythrocytes do?
transport oxygen and carbon dioxide between tissues and lungs
302
what is hemoglobin?
red pigmented protein that transports oxygen and CO2
303
explain a hemoglobin molecule
4 protein building blocks called globins, 2 alpha and 2 beta, each have a heme group that has iron in the center - O2 binds to the iron - so each hemoglobin can carry 4 oxygens
304
who produces erythropoeitin?
kidneys primarily, liver small amount
305
How does EPO (erythropoietin) regulate erythrocyte production?
kidney detects decreased blood O2, kidney cells release EPO into blood, EPO stimulates red bone marrow to increase the rate of production of erythrocytes, net effect: increased numbers of erythrocytes enter circulation, lungs oxygenate erythrocytes and blood O2 level increases
increased O2 levels are detected by the kidney, which inhibits EPO release by negative feedback
306
how does the adrenal gland participate in erythropoeisis?
secretes testosterone which stimulates kidneys to produce more EPO.
307
what is the down side to increased rbc's in blood?
increases viscosity which could increase chance of cardiovascular complications (blood clots leading to heart attacks or strokes)
308
What happens as erythrocytes age?
removed from circulation - phagocytized in spleen and liver by macrophages
309
what molecular components of hemoglobin have to be accounted for in destruction of erythrocytes?
globin protein
iron ion
heme group
310
what happens to the globin proteins of hemoglobin?
broken down into amino acids and reenter the blood. some may be used to make new erythrocytes
311
what happens to the iron ions of hemoglobin?
transported by globulin protein called transferrin to the liver. Fe2+ then bound to storage proteins called ferritin and hemosiderin. stored mainly in liver and spleen then transported by transferrin to red bone marrow as needed for erythrocyte production.
some iron lost in feces, sweat, urine and menstrual flow
312
what happens to the heme group of hemoglobin?
converted within macrophages to biliverdin and bilirubin, transported by albumin to the liver - eventually expelled in feces, urine or absorbed back into blood
313
what determines your ABO blood type?
presence of two surface antigens, A antigen and/or B antigen
314
what kinds of antigens are present on RBC's for each blood type?
Type A: antigen A
Type B: antigen B
Type AB: antigens A and B
Type O: neither antigen
315
what antibodies are present in the blood plasma of each ABO blood type?
Type A: anti-B antibodies
Type B: anti-A antibodies
Type AB: neither Anti-A nor anti-B antibodies
Type O: both Anti-A and anti-B antibodies
316
what is agglutination?
when antibodies in plasma bind to surface antigens of transufed erythrocytes and clump them together
317
what is hemolysis?
when erythrocytes rupture
318
why is hemolysis bad?
releases fragments into the blood - osmotic pressure - ultimately can damage organs
319
What determines Rh blood type?
Rh+ has surface antigen D
| Rh- has no surface antigen D
320
how is Rh antibody production different than ABO?
Rh antibodies not present until they are exposed to foreign antigen. so an Rh negative individual does not have anti-D antibodies until she is exposed to Rh+ blood.
321
which type of Rh blood can have anti-D antibodies?
only Rh- after exposure to Rh+ blood
322
what is hemolytic disease of the newborn (HDN?)
when Rh- mother has been exposed to Rh+ blood previous to pregnancy, Rh+ fetus is attacked by anti-D antibodies in mother.
323
what is anemia?
any condition in which either the percentage of erythrocytes is lower than normal or the oxygen-carrying capacity of the blood is reduced
lethargy, shortness of breath, pallor of the skin and mucous membranes, fatigue & heart palpitations
324
how are leukocytes different from erythrocytes?
leukocytes have nucleus and cellular organelles, 1.5-3 times bigger, and don't contain hemoglobin.
325
what is diapedesis?
the process where leukocytes enter the tissues from blood vessels by squeezing between the endothelial cells of the blood vessel wall.
326
what is chemotaxis?
process in which leukocytes are attracted to a site of infection by the presence of molecules released by damaged cells, dead cells, or invading pathogens.
327
describe neutrophils
multilobed nucleus, neutral or pale granules, 50-70% of total leukocytes
328
what is the function of neutrophils?
phagocytize pathogens, especially bacteria
| release enzymes that target pathogens
329
describe eosinophils
nucleus is bilobed
cytoplasm is reddish or pink-orange
1-4% of total leukocytes
330
what is the function of eosinophils?
phagocytize antigen-antibody complexes and allergens
| release chemical mediators to destroy parasitic worms
331
describe basophils
nucleus is bilobed
| cytoplasm contains deep blue-violet specific granules (dark dark hard to see)
332
what is the function of basophils?
release histamine (vasodilator and increases capillary permeability) and heparin (anticoagulant) during inflammatory reactions
333
describe lymphocytes
round or slightly indented nucleus - fills the cell in smaller lymphocytes
agranular
nucleus is usually dark stained
thin rim of cytoplasm surrounds nucleus
334
what is the function of lymphocytes
coordinate immune cell activity
attack pathogens and abnormal and infected cells
produce antibodies
335
describe monocytes
kidney-shaped or C-shaped nucleus
nucleus is generally pale staining
agranular
abundant cytoplasm around nucleus
336
what is the function of a monocyte?
```
exit blood vessels to become macrophages
phagocytize pathogens (bacteria, viruses), cellular fragments, dead cells, debris
```
337
name the leukocytes in order of relative abundance
```
never let monkeys eat bananas
neutrophils
lymphocytes
monocytes
eosinophils
basophils
```
338
what is leukopenia?
reduced number of leukocytes
| decreases ability to fight infection effectively
339
what is leukocytosis?
elevated leukocyte count
340
what are associated with neutrophilia
increased neutrophil count
| acute bacterial infections, acute stress, and tissue necrosis
341
what is decreased neutrophil count?
neutropenia
| may be due to certain anemias, drug or radiation therapy
342
what causes lymphocytosis?
increased number of lymphocytes
| viral infections like mumps, rubella or mono
343
how are platelets different from erythrocytes
neither have a nucleus, but platelets never did have one
344
what is hemostasis?
process where the blood clots and stops blood flow through an injured blood vessel wall
345
what are the three phases of hemostasis?
vascular spasm
platelet plug formation
coagulation phase
346
what is vascular spasm
when a blood vessel is injured, blood vessel constricts suddenly to limit the amount of blood that can leak from damaged vessel
lasts from a few to many minutes
347
what is prostacyclin?
an eicosanoid that normally coats the inner lining of a blood vessel - serves as platelet repellent
348
what happens when blood vessel is damaged?
collagen fibers within the ct beneat the endothelial cells in vessel wall become exposed, platelets stick to them with help of plasma protein called von Willebrand factor - bridge between platelets and collagen fibers.
349
What happens to platelets as they start to form plug?
morphological change - develop long processes and become activated->cytoplasm granulates and releases chemicals to assist with hemostasis
350
when platelets are activated, what happens in response to the released chemicals?
prolonged vascular spasm (with release of seratonin and thromboxane A2)
attraction of other platelets (with release of adenosine diphosphate and thromboxane A2)
stimulation of coagulation (with release of procoagulants)
repair of blood vessel
351
what are two ways to initiate the coagulation cascade?
intrinsic pathway and extrinsic pathway
352
how is the intrinsic pathway initiated?
by damage to the inside of the vessel wall - initiated by platelets
takes approximately 3-6 minutes
353
how is the extrinsic pathway initiated?
by damage to the tissue that is outside the vessel - usually takes about 15 seconds
354
what are the steps of the intrinsic pathway?
platelets adhere to a damaged vessel wall and release factor XII
factor XII converts the inactive factor XI to the active factor XI
factor XI changes inactive factor IX to active factor IX
factor IX binds with Ca2+ and platelet factor 3 to form a complex that converts inactive factor VIII to active factor VIII
factor VIII changes inactive factor X to active factor X
355
what are the steps of the extrinsic pathway?
tissue thromboplastin is released from damaged tissues and combines with factor VII and Ca2+ to form a complex
complex converts inactive factor X to active factor X
356
what are the steps of the common pathway?
factor X combines with factors II and V, Ca2+ and platelet factor 3 to form prothrombin activator
prothrombin activator activates prothrombin to thrombin
thrombin converts soluble fibrinogen into insoluble fibrin
in the presence of Ca2+, factor XIII is activated, factor XIII cross-links and stabilizes the fibrin monomers into a fibrin polymer that serves as the framework of the clot
357
what happens when over 10% of blood is lost?
sympathetic division of autonomic nervous system is activated - vasoconstriction, increased heart rate, increased force of heart contraction to maintain blood pressure - blood flow is also redistributed to heart and brain.
358
how does a clot get eliminated?
clot retraction and fibrinolysis
359
what is clot retraction?
actinomyosin (a contractile protein in platelets), contracts and squeezes the serum out of the developing clot - pulls sides of vessel wall closer together and makes clot smaller.
360
what is fibrinolysis?
plasmin degrades fibrin strands - the fibrin framework of the clot
begins within 2 days of clot formation & occurs slowly over a number of days
361
What is sickle cell anemia?
a genetic disorder in which abnormal hemoglobin is produced
362
what is aplastic anemia?
bone marrow is destroyed or severely inhibited
363
what is hemorrhagic anemia?
a consequence of acute blood loss
364
what is pernicious anemia?
trouble with vitamin 12 uptake
365
what is hemolytic anemia?
a common occurrence after a transfusion error
