term3 Flashcards
1
Q
what is the purpose of the endocrine system?
A
to maintain internal environment, adapt to stress, control growth and metabolism and reproduction
2
Q
what is the effect of the endocrine system when compared to the nervous system?
A
slower but more widespread
3
Q
what are endocrine glands? what do hormones do?
A
group of specialized cells which secrete chemicals known as hormones into circulation till it finds the cells with the receptor for that hormone. hormone will stimulate or inhibit cell activity
4
Q
what are the types of hormones and which are hydrophobic/hydrophilic?
A
protein hormones are hydrophilic. steroid and thyroid hormones are hydrophobic
5
Q
describe hydrophilic hormones
A
can circulate freely thru blood. cant diffuse thru membrane so receptor must be on the membrane of target cell
6
Q
describe hydrophobic hormones
A
require protein carrier to circulate. can diffuse thru membranes meaning receptors are located inside the cell - could be on nucleus or in cytoplasm
7
Q
describe the process a hydrophobic hormone must undergo to fulfill its job
A
released by protein carrier before entering cell. binds to receptor in cytoplasm or nucleus. forms hormone/receptor complex which will bind to DNA in nucleus altering the cell activity
8
Q
describe the process a hydrophilic hormone must undergo to fulfill its job
A
hormone attaches to receptor to start chemical reaction sequence. it affects cell thru 2nd messenger system, tyrosine kinase, and/or G proteins
9
Q
how is a 2nd messenger produced? how does it work?
A
produced by G proteins when hormone, the 1st messenger binds to a receptor. the 2nd messenger is released into the cytoplasm, altering proteins in the cell and triggering reactions which could lead to the release of proteins
10
Q
what does tyrosine kinase do?
A
it is activated on the inside membrane by the hormone receptor complex. then altering cell’s proteins along with the cell’s activity
11
Q
how are ion channels involved with receptors? explain the process
A
hormone attaches to the receptor, activating G proteins and opening adjacent ion channels. IF ion is calcium, it acts as 2nd messenger.
12
Q
how are hormones broken down after completing their job?`
A
removed thru metabolic destruction in blood or by tissue, excretion by liver into bile, or excretion by kidney into urine
13
Q
what does the hypothalamus do in relation to endocrine system?
A
releases hormones which will release or inhibit other hormones from the anterior pituitary gland
14
Q
what are the hormones released from the hypothalamus?
A
prolactin releasing/inhibiting, growth hormone releasing/inhibiting, thyrotropin releasing, corticotropin releasing, gonadatropin releasing
15
Q
what regulates the anterior pituitary gland?
A
special circulatory system, hypothalamic-hypophyseal portal system which connects the brain to the gland.
16
Q
what hormones does the posterior pituitary gland release?
A
releases neurohormones such as oxytocin and antidiuretic into blood in response to action potentials. there are produced in the hypothalamus.
17
Q
after being released from the hypothalamus, what does the thyroid releasing hormone do?
A
causes the release of thyroid stimulating hormone from the anterior pituitary gland which causes the release of thyroid hormones T3 and T4 from the thyroid gland.
18
Q
after being released from the hypothalamus, what does the corticotropin releasing hormone do?
A
causes the release of adrenocorticotropin from the anterior pituitary gland which causes the release of cortisol from adrenal glands.
19
Q
after being released from the hypothalamus, what does the growth hormone releasing/inhibiting do?
A
causes the release of growth hormone from the anterior pituitary gland which acts on tissues. inhibiting prevents this process
20
Q
after being released from the hypothalamus, what does the gonadotropin releasing hormone do?
A
causes the release of luteinizing and follicle stimulating hormone which act on testes and ovaries
21
Q
after being released from the hypothalamus, what does the prolactin releasing/inhibiting hormone do?
A
causes the release of prolactin which causes the production breast milk
22
Q
what can hormones from the anterior pituitary and other glands do?
A
they can feed back into the hypothalamus and/or the anterior pituitary to decrease the release of their respective hormone
23
Q
where is the thyroid gland?
A
below larynx, the voice box
24
Q
what does T3 and T4 do?
A
regulate metabolic basal rate (the minimum rate to maintain body) of oxygen and energy
25
are T3 and T4 hydrophobic or hydrophilic? what does this mean?
hydrophobic, meaning they require a protein carrier to circulate blood but can diffuse thru membrane
26
what is the thyroid gland made up of?
colloids which are each surrounded by follicles and then another layer of epithelial cells
27
describe the thyroid hormone production process
iodine and tyrosine combine with the help of thyroglobulin producing T3 and T4. tyrosine is taken from circulation by epithelial cells and combines with thyroglobulin from the cell. separately, epithelial cells collect iodine. tyrosine-thyroglobulin complex is secreted into colloid as one or two iodine attach to each tyrosine molecule. the amount of iodine determines if its T3 or T4
28
what are the percentages of thyroid hormones released?
90% for T4 and 10% for T3
29
what is cretinism?
occurs from insufficient amount of thyroid hormones (hypothyroidism) when the gland is unable to produce T3 and T4 due to genetic defect or lack of iodine in diet
30
what is goiter?
leads to enlargement of thyroid gland. caused by insufficient iodine to too much thyrotropin releasing hormone (TRH). with no iodine there's no T3/T4 no negative feed back more TRH/TSH and enlarged thyroid
31
where are the adrenal glands?
two, one on top of each kidney
32
what are the different layers of the adrenal cortex and what does each secrete?
outer layer glomerulosa secretes aldosterone which helps regulate mineral and fluid. middle layer fasciculata secretes cortisol which helps in glucose metabolism. inner layer reticularis secretes androgens, a sex steroid.
33
what does the medulla of the adrenal gland secrete?
epinephrine
34
what can be said about all the hormones the adrenal gland secretes?
they are all steroids, therefore, hydrophobic
35
what can be said about stress and hormone production?
stress increases cortisol production and/or secretion. this helps increase the blood's glucose levels while also decreasing protein and lipid synthesis
36
how does stress stimulate the adrenal gland?
it stimulates cortisol releasing hormone (CRH) secretion from the hypothalamus, which stimulates adrenocorticotropic hormone (ACTH) from the anterior pituitary, further stimulating the adrenal glands to release cortisol, aldosterone, and androgens. the cortisol from the gland can go to the hypothalamus/anterior to decrease their production
37
describe the pancreas structure
contains endocrine tissues to secrete hormones into the blood and exocrine tissues to secrete chemicals thru a duct into the digestive tract.
38
what are the 3 cell types in the pancreas and what do they secrete?
alpha secretes glucagon. beta secretes insulin and amylin. delta secretes somatostatin into the digestive tract.
39
what does insulin do?
causes cells to take up, store, and use glucose. therefore, decreasing glucose levels
40
what does glucagon do?
increases blood glucose concentration by stimulating glycogenolysis and gluconeogenesis
41
what is the difference between glycogenolysis and gluconeogenesis?
glycogenolysis is the breakdown of glycogen to glucose while gluconeogenesis is the formation of glucose from the nonglucose fuels
42
what does somatostatin do? when and where is it released?
reduces insulin and glucagon secretion. released into digestive tract when both blood glucose and amino acid levels rise.
43
describe type 1 diabetes
damaged beta cells lead to lack of insulin production causing glucose levels to increase because cells cant use glucose without insulin. cells resort to fat and amino acids leading to serious consequences
44
describe type 2 diabetes
cells become resistant to insulin's usual uptake and storage effects leading to an increase in glucose levels. this causes more insulin to be released, depleting beta cells, and eventually decreasing insulin release
45
for what duration of development, does the embryo have indifferent gonads?
first 6 weeks
46
when do testes start to develop? what about ovaries?
testes around 6-7 weeks. ovaries after around 9 weeks
47
which of the reproductive tracts require hormonal input to develop? describe the process for it and the other tract.
male reproductive tract. at 7 weeks, testicular cells produce mullerian inhibiting hormone which causes the mullerian duct to regress. at 9 weeks testicular cells produce testosterone to stimulate the wolffian duct to develop into other parts of the tract. testosterone also leads to development of male genitalia. for the female reproductive tract, the mullerian duct develops and wolffian duct regresses
48
what do testes produce?
testosterone and sperm
49
describe the "life" of sperm? where its stored, goes thru, etc. also tell the benefits of fluids sperm mixes with.
after production, it is stored in the epididymis. during the process of ejaculation, it travels thru ductus deferens and mixes with fluid from seminal vesicles which helps maintain and nourishes sperm. from there it passes thru prostate and mixes with fluid from bulbourethral gland which helps neutralize the pH and lubricate the urethra and the vagina for sperm. then it enters the urethra and leaves the body
50
what is spermatogenesis and when and where does it occur?
it is the production of testosterone and sperm which occurs after puberty in the seminiferous tubules.
51
describe the process of spermatogenesis and also mention how many chromos and when the amount changes
there are 46 chromosomes in a spermatogonia which is located at the edge of seminiferous tubules. spermatogonia divides by mitosis into a spermatogonia and a primary spermatocyte, both of which have 46 chromosomes each. the primary spermatocyte divides by meiosis into 2 secondary spermatocytes and then into 4 spermatids which are nourished by sertoli cells as they move thru the tubule. the spermatids develop into sperm cells and released by sertoli cells into lumen of seminiferous tubules. the sperm cell contains 23 chromos
52
where do sperm cells mature?
in the epididymis
53
what nourishes spermatids?
sertoli cells
54
by what process does spermatogonia divide?
mitosis
55
by what process do spermatocytes divide by?
meiosis
56
what controls testicular function?
follicle stimulating hormones (FSH) and luteinizing hormones (LH) released in response to gonadotropin releasing hormones (GnRH)
57
what does follicle stimulating hormones (FSH) promote?
promotes spermatogenesis by acting on sertoli cells. it also produces a hormone inhibin which goes back to anterior to decrease LH and FSH production
58
what does luteinizing hormones (LH) promote?
stimulates leydig cells to produce testosterone. the testosterone will go to anterior to decrease LH & FSH production and secretion
59
when are testosterone levels high?
during development and after puberty
60
why may andropause occur?
due to leydig cells not fully responding to luteinizing hormones (LH)
61
how does the sperm travel thru the female reproductive tract following ejaculation? how does it meet the egg
thru cervix to the uterus and then the fallopian tubes. here it will meet the egg released from ovaries thru the fimbria
62
what is produced in the female reproductive system that helps fascilitate or prevent sperm entry?
mucus is produced from the cervix. thin mucus helps facilitate while thick prevents sperm entry
63
where is the egg fertilized?
in the fallopian tubes
64
what hormones does the ovaries produce?
estrogen and progesterone
65
what is oogenesis?
the development of the egg
66
describe the process of oogenesis
egg is contained in follicle. millions of oogonia are produced in the developing embryo. the oogonia develops into primary follicle which is a primary oocyte surrounded by granulosa cells. these cells produce fluid into interior antrum. this stays same until puberty. AT PUBERTY, LH & FSH activate the ovaries. few primary follicles begin growth. they develop another ring of theca cells outside the granulosa cells. the primary follicle becomes a mature follicle. before ovulation, the oocyte separates from the granulosa cells and floats freely in the antrum
67
describe the process of ovulation
more estrogen is produced in ovaries causing granulosa of follicle cells to grow. leads to more estrogen production which feeds into the anterior. UNLIKE OTHER PROCESSES THIS CAUSES AN INCREASE IN LH & FSH LEVELS. the LH surge causes granulosa cells to secrete fluid into antrum and the follicle to swell, rupture, and expel the egg. the fimbrae gathers the egg into fallopian tube.
68
what process involving hormones has positive feedback loop with the anterior and hypothalamus?
ovulation involving LH and FSH
69
what happens to the egg if there is no pregnancy?
the mature follicle in the fallopian tube will degenerate. hormone release causes the corpus luteum to degenerate to corpus albicah
70
what does estrogen do?
develops and maintains female characteristics. thickens lining of uterus for pregnancy
71
what does progesterone do?
preps body for pregnancy. if no pregnancy, corpus luteum breaks down and progesterone levels decrease
72
what leads to ovulation?
the fluctuation of LH & FSH on a monthly basis
73
what are the phases of the menstrual cycle?
menses, proliferative, and secretory/luteal
74
describe the menses phase. include duration
day 0 to 7. levels of LH, FSH, estrogen, and progesterone are low. lining of uterus is lost. end of cycle and repeat
75
describe the proliferative phase. include duration
day 7 to 14. LH & estrogen production increases as the follicle ruptures and the egg is expelled. estrogen & progesterone stimulates the growth of the uterus lining
76
describe the secretory/luteal phase. include duration
day 14 to 28. follicle develops into the corpus luteum --- and if one is pregnant, it leads to an increase in progesterone which is needed for implantation. if not, luteum degenerates into corpus albicans and progesterone level drops
77
how does the birth control work?
it contains synthetic estrogen and progesterone which feeds into the hypothalamus to decrease GnRH levels and into the anterior to decrease LH & FSH levels. the low FSH suppresses follicle development while low LH suppresses ovulation. progesterone also decreases motility of uterus and fallopian tubes
78
what is anabolism?
formation. small molecules form large molecules using ATP
79
what is catabolism?
breakdown. large molecules breakdown into smaller molecules releasing ATP
80
what are the building blocks of food? their storage forms?
triglycerides (fatty acids stored as triglycerides), proteins (amino acids stored as cellular proteins), and carbohydrates (glucose stored as glycogen)
81
what are the 3 metabolic processes?
glycolysis, citric acid cycle, oxidative phosphorylation
82
where does glycolysis take place? what does it do?
in the cytoplasm. it produces 2 ATP using 1 glucose
83
where does citric acid cycle take place? what does it do?
inside the mitochondria. it produces 2 ATP from 1 glucose.
84
where does oxidative phosphorylation take place? what does it do?
inside the mitochondria. it produces 34 ATP
85
which of the metabolic processes don't require oxygen?
glycolysis only
86
how do molecules enter the metabolic processes?
glucose and glycogen can enter glycolysis. amino acids are converted to pyruvate to enter glycolysis or to Acetyl CoA to enter citric acid cycle. fat is broken down to glycerol and free fatty acids to enter glycolysis and citric acid cycle respectively
87
what "building block" does the brain use and therefore important?
glucose
88
where is glucose stored?
in the liver and skeletal muscles
89
describe the process of glycolysis
glucose is converted to a glucose-6-phosphate (G6P). from there G6P enters glycolysis to produce ATP (orrr converted to glycogen to be stored where it can revert to enter cycle) and pyruvate.
90
what happens to pyruvate after glycolysis? what does it depend on?
pyruvate can go thru citric acid cycle and produce lots of ATP with the help of oxidative phosphorylation. OR it can enter different small reactions to produce a bit of ATP & lactase. which reaction occurs depend on the presence of oxygen. no oxygen means lactase
91
describe the process of citric acid cycle
pyruvate becomes acetyl CoA which produces 36 ATP, carbon dioxide, and water after both the citric acid cycle and oxidative phosphorylation
92
what is the fed state? the fasted state?
fed state is when there are high level of nutrients in the blood so the body stores the fuel for later use. fasted is when there are low levels so body uses stored nutrients to maintain blood glucose levels. in the fasted state, it'll enter metabolic processes to produce ATP.
93
what is gluconeogenesis?
liver makes new glucose from glycerol, amino acids, pyruvate, and lactate to supply the brain, etc
94
what regulates the fed state? what does it lead to?
insulin secreted from beta cells in response to high glucose levels. it promotes storage of food nutrients while inhibiting storage release. leads to increased glucose intake, glycogen formation, triglyceride formation, protein synthesis as well as decrease in blood glucose, fatty acid, & amino acid levels
95
what regulates the fasted state?
glucagon regulates the fasted state. it is secreted by alpha cells in the pancreas when there are lower glucose levels. it stimulates cells to release fuel stores into the blood. leads to increased glycogenolysis & gluconeogenesis & lipolysis (breakdown of lipids) . this results in increased blood glucose & fatty acid levels.
96
what do T3 & T4 do in relation to energy and metabolism?
it increases breakdown & the release of energy stores.
97
what does epinephrine do in relation to energy and metabolism?
increases glucagon levels and decreases insulin levels. causing the release of stored fuels
98
what does cortisol do in relation to energy and metabolism?
release of energy stores when under stress
99
what is the purpose of the salivary glands?
produces saliva to moisten and begin digestion of carbohydrates
100
what is the purpose of the stomach?
stores, mixes, and digests some food. delivers to small intestine
101
what is the purpose of the liver in the digestive system?
produces and secretes bile
102
what is the purpose of the pancreas in the digestive system?
secretes enzymes, hormones, & bicarbonate
103
what is the purpose of the small intestine?
allows digestion & absorption of most food particles
104
what is the purpose of the large intestine?
stores & concentrates undigested material. also absorbs salt & water
105
what is secretion in the digestive tract?
digestive fluids such as water, mucus, bile salts, enzymes, and acids are released into the digestive tract's lumen
106
what is digestion?
food broken into smaller molecules by digestive enzyme
107
what is absorption in the digestive tract?
small molecules taken by circulatory system & distributed around the body
108
what is motility in the digestive tract?
movement of food thru digestive tract by smooth muscle contraction
109
what is excretion in the digestive tract?
removal of waste product from body
110
what is the makeup of saliva?
99% water, rest is ions & protein
111
what is name of food mixed with saliva?
bolus
112
what are the different salivary glands and what do they do?
parotid, sublingual, and submandibular. begins digestion of carbs
113
describe the muscle contractions in digestive tract. what is it called?
peristalsis. wave like muscle contractions
114
what is the pyloric sphincter?
regulates emptying of stomach into small intestine
115
what does the rugae do for the stomach?
increases surface area & allows stomach to expand for food
116
what is chyme?
mixture of liquefied bolus, etc. slow released into small intestine
117
where is most of the absorption done in the digestive tract?
small intestine
118
when does proteins begin to be digested?
in the stomach
119
how does mucus aid in the digestive tract? where is it secreted from
secreted by stomach's body and antrum's cells. it protect stomach from acidic environment from the HCl
120
what is secreted in stomach?
mucus, HCl, pepsinogen, gastrin, and intrinsic factors
121
where is HCl secreted from in the stomach? what does it do?
by parietal cells. it denatures proteins & tissues of meat & kills bacteria. it also converts pepsinogen to pepsin
122
what does pepsin do? where it it from?
pepsin helps digest large protein molecules. it is from pepsinogen which is converted with the help of HCl
123
what is pepsinogen? secreted from what?
secreted from the stomach's body cells. it is converted to pepsin with the help of HCl. pepsin helps digest large protein molecules
124
what is gastrin? secreted from what?
secreted from the stomach's antrum cells, G cells. it stimulates HCl secretion
125
what is the ileocecal sphincter? what is it made up of?
it is connected to pyloric sphincter. it empties into the the ascending colon of large intestine. it is made up of duodenum, jejunum, and ileum
126
where does most of digestion and absorption take place in the large intestine?
the duodenum and jejunum
127
what aids in the digestion of fat? it is an enzyme?
bile which is not an enzyme
128
what is the single building block for carbohydrates?
monosaccharides
129
what must happen to carbohydrates to be absorbed?
to be absorbed, carbs must be broken down into monosaccharides. they are absorbed by transport systems in the small intestine's wall
130
describe the digestion process of carbohydrates
in the mouth, amylase breaks down polysaccharides into smaller polysaccharides. in the stomach carbohydrates stop digesting due the to the acidic environment denaturing amylase. process continues in the small intestine due to pancreas secreting amylase into the duodenum and the bicarbonate neutralize the stomach's acids.
131
what can neutralize the stomach's acidic environment?
bicarbonate
132
describe the absorption process of carbohydrates
Na/K pumps are located in epithelial cells of the intestine which makes the Na concentration gradient high on the outside of the cells. the gradient powers the Na/glucose co transporter on the luminal side of the cell. the glucose moves into the cell with the Na (down the sodium concentration gradient). the glucose then diffuses out the cell thru facilitated diffusion
133
describe the digestion process of proteins
it begins in the stomach. HCl converts inactive pepsinogen to active enzyme pepsin while also denaturing protein strands helping pepsin digest the long chains to smaller chains called polypeptides that will enter the small intestine. the pancreatic enzymes will continue digestion but it requires neutral environment which is made with the help of bicarbonate. neutral pH inactivates pepsin so trypsin and chymotrypsin continues the process. proteas from pancreas digests proteins to amino acids. now absorption can occur.
134
describe the absorption process of proteins
absorption uses 2ndary active transport which requires a Na concentration gradient to power the co-transport that moves amino acids into the cell
135
what inactivates pepsin?
a neutral environment achieved by bicarbonate
136
what is emulsification?
prevents small drops to go back to larger drops. done with the help of bile
137
what is colipase? what is it used for?
protein secreted from the pancreas to help lipase reach the the bile coated lipid droplets to be digested
138
describe the digestion process of lipids
lipase attacks the phospholipids in the lipids removing the 2 fatty acid and leaving the monoglycerides behind. fat droplets get smaller as they're being digested, forming a sphere - a lipid droplet covered in bile salt
139
describe the absorption process of lipids
fatty acids & monoglycerides are both lipid soluble therefore can diffuse thru small intestine's epithelial cell's membranes. cholesterol enters cell thru active transport systems.
140
where does the body absorb water from? give percentages
80% from saliva, 20% from consumption
141
what parts of the digestive tract absorbs the water?
40% absorbed by the duodenum & jejunum. 38% by the ileum. and 1.5% by large intestine. rest is excreted
142
describe the absorption of ions in the digestive tract
Na/K pump on intestinal cell creates Na concentration gradient (low inside). the Na moves into cell from intestine's lumen. the Na is absorbed with the carbohydrates and amino acids. K is absorbed passively, the K increases in the lumen causing it to diffuse into the cell.
143
what regulates the digestive tract's absorption and regulation?
nothing, it is unregulated. but the muscle contractions and enzyme secretion are regulated thru hormonal & neural mechanisms
144
what does the ANS do in regards to the digestive tract?
it alters the nerves of the enteric nervous system, impacting smooth muscles of the tract's walls, enzyme secreting cells, endocrine cells, & blood vessels of the tract.
145
describe the short loop of the enteric nervous system. give an example
begins with mechanical distension (stretching of the tract) or chemical changes (pH, osmolarity, etc). these are detected by the sensors which initiates a reflex. activates effector organs. for example, secretory cells releasing enzymes or smooth muscles altering gastric motility
146
what is mechanical distension
stretching of tract
147
describe the long loop of the enteric nervous system
stimuli includes sight/smell. these are detected by sensors (eye, nose, etc). signals sent thru PSYN to the enteric nervous system to change digestive function - increasing gastric motility, secretions, & production of saliva
148
what controls the slow release of chyme into the intestines? how does this benefit?
gastrointestinal motility. slow release allows digestion and absorption be maximized
149
how does gastrointestinal motility work? describer BER
interstitial cells of the tract (specialized smooth muscle cells) spontaneously alter membrane potentials producing basal electric rhythms (BER) that travel down the digestive tract. these potentials usually don't cause contractions unless they reach the threshold with an additional stimulus. the waves move thru gap junctions
150
what does secretin do? secreted in response to what?
secreted in response to to acid in intestine. it inhibits stomach emptying and causes bicarbonate to be released from pancreas and bile from liver
151
what is cholecystokinin (CCK)? secreted in response to what?
secreted in response to presence of fat. it slows the emptying of stomach and stimulates the pancreas to release digestive enzymes and gallbladder to release bile
152
what is glucose dependent insulinotrophic peptide? secreted in response to what?
secreted due to glucose & amino acids (food). stimulates release of insulin and inhibits emptying of stomach.
153
what is gastrin? secreted by what in response to what?
secreted by G cells in response to protein, mechanical distension of food, & stimulation from PSYN. gastrin leads to secretion of HCl which converts pepsinogen to pepsin to digest proteins
154
what are the 3 phases of gastric acid secretion? what do they stand for?
cephalic brain. gastric stomach. intestinal intestine
155
describe the cephalic phase of gastric secretion
increased gastric acid secretion due to senses related to food such as smell. anticipatory response due to activation of enteric nervous system thru long loop reflex causing parietal cells to release HCL & G cells to release gastrin to increase motility of stomach
156
describe the gastric phase of the gastric secretion
stimulated by the presence of food in stomach causing muscle distention and amino acids from protein breakdown. this triggers short loop reflex involving enteric nervous system. HCl, gastrin, pepsinogen are released increasing gastric motility.
157
describe the intestinal phase of gastric secretion
simulated by presence of glucose, fat, & acidic chyme in intestine. leads to decrease in motility and inhibition of secretions in stomach. caused by enteric nervous system and hormones such as CCK, secretin, & glucose dependent insulinotrophic peptide
