RAT 21 Flashcards
(127 cards)
1
Q
what is the name of the process in which the female gamete is produced?
A
oogenesis
2
Q
describe the stages of oogenesis and when each occurs.
A
- before birth: months 2-7 of the fetal period; oogonium undergoing mitosis formation of primary oocyte
- childhood to puberty: number of oocytes has dropped to ~ 300,000
- puberty to menopause: polar cell and secondary oocyte; fetilization occurs in this phase
3
Q
when do the mitotic dividions take place in females?
A
before birth, during moths 2-7 of fetal development
4
Q
between puberty and menopause, about how many primary oocytes are stimulated to continue development each month?
A
20-30
5
Q
how many will complete development?
A
usually only one per month
6
Q
what is the purpose of the polar body?
A
the smaller cell, first produced contains DNA but very little cytoplasm and often degenerates
7
Q
what is the purpose of the secondary oocyte?
A
- contains DNA and most of the cytoplasm plus absorbed ECF
- cytoplasm ensures it will be fertilized
- potential to become an ovum
8
Q
when does the secondary oocyte complete mitosis?
A
when it becomes fertilized
9
Q
about how many primary oocytes are found in a newborn? about how many will reach maturity and ovulate?
A
- 1-2 million
- 400-500
10
Q
why is this more complicated in females than in males?
A
- the structure of the gametes
- cytoplasm is needed to nourish the secondary oocyte
11
Q
what is an ovarian follicle?
A
blister like structures in the ovarian cortex that mature along with the oocyte; where oocytes reside
12
Q
what are the first follicles that formed called?
A
- primordial follicles
13
Q
what do primordial follicles becomes as they mature?
A
primary follicles
14
Q
what do primary follicles become as they mature?
A
secondary follicles
15
Q
what happens to most primordial follicles?
A
stop maturing and instead die by atresia
16
Q
what is the ovarian cycle?
A
a monthy series of cyclic hormone changes and events controlled by the HPG axis
17
Q
how many follicles typically develop into a mature follicle each month?
A
one
18
Q
what is the first phase of the ovarian cycle? when does it occur in a woman’s lifetime?
A
- follicular phase
- childhood to menopause
19
Q
describe the primordial follicle
A
primary oocyte surrounded by a single layer of squamous follicle cells
20
Q
describe the primary follicle. what is the shape of the granulosa cells?
A
- follicle cells become cubodial granulosa cells
- microvilli and thecal cells develop
- cubodial
21
Q
describe the secondary follicle
A
- primary oocyte surrounded by multiple layers of granulosa cells
- follicular fluid found in small cavities around the oocyte
22
Q
describe the vesicular (tertiary) follicle.
A
- primary oocyte finished meiosis I to become secondary oocyte
- surrounded by granulosa cells and fluid-filled antrum
- maturation of a primordial follicle to this stage takes ~ 350 days
23
Q
typically, how many follicles become a tertiary follicle each month?
A
one
24
Q
what is the name of the fluid-filled cavity?
A
antrum
25
in which type of follicle does the primary oocyte complete meiosis I to become a secondary oocyte?
vesicular follicle
26
in what phase of meiosis is the secondary oocyte suspended? when would it compelte meiosis?
- metaphase II
- when fertilization occurs
27
how long does it take for a follicle to mature into a vestivular follicle?
90-120 days
28
what is ovulation?
the process by which the ovary expels a secondary oocyte
29
the ovulated oocyte is in which stage of development?
stage 5
30
what typically happens to the ovulated oocyte?
taken to the uterine tube, moved toward the uterus
31
what happens if two follicles mature and both secondary oocytes are fetilized?
fraternal twins
32
what can lead to identical twins?
fertilization of a single oocyte by a single sperm, followed by the separation of the diving cellls in early development
33
what happens to the remainder of the follicle in the ovary after ovulation?
becomes the corpus luteum
34
what hormones are secreted by the corpus luteum?
- progesterone
- some estrogen
35
what happens to the corpus luteum if a pregnancy occurs?
persist for approximtely 3 months to produce hormones
36
what happens to the corpus luteum if a pregnancy does not occur?
begins to degenerate in ~10 days and stops producing horomones
37
what is the corpus albicans?
a whitish know of scar tissue
38
assuming a 28-day cycle, when does the follicular, ovulation, and luteal phase occur?
- follicular: 1-14
- ovulation: 14
- luteal: 14-28
39
do most women have a 28-day cycle? how does this vary?
- no: fewer than 25%
- anywhere form 21-40 days
40
which phase of the cycle is less variable?
luteal phase
41
what is the HPG axis?
the multi-tiered feedback loops of the hormones of the hypothalamus, anterior pituitary, and gonads
42
what is the first-tier control?
hypothalamas releases GnRH
43
what is the second-tier control?
GnRH stimulates the anterior pituitary to release FSH and LH
44
what is the third-tier control?
- the ovaries are the target of FSH and LH
- LH stimulates androgens
- FSH stimulates androgens conversion to estrogen
45
what are the effects of the HPG axis?
- estrogen stimulates a sominant follicle to mature to a vestibular follicle
- the new vestibulat follicle produces large amounts of estrogen, triggering and LH surge
- the LH surge and FSH trigger ovulation
46
what are some other effects of female hormones?
- estrongen
- maturation of the sex organs
- development of external genitalia
- maintanence of anatomical feature unique to
adult females
- progesterone
- maintaining pregnancy
47
what is the uterine cycle? what is another term for this cycle?
- the series of cycic changes that the uterine endometrium goes through each month as it responds to the fluctuating levels of ovarian hormones
- menstrual cycle
48
what is the endometrium?
the innermost tissue layer of the uterus composed of simple columnar epithelium
49
what is the stratum functionalis?
- functional layer
- undergoes cyclic changes in response to ovarian hormones
50
what is the stratum basalis?
- basal layer
- thinner, deeper; doesn't thicken in response to ovarian hormones but forms a new stratum functionalis after mensturation ends
51
what are the spiral arteries?
uterine arteries that have branched several times
52
what are the three phases of the uterine cycle? when does each occur (given a 28-day cycle)?
- menstrual phase (days 1-5)
- proliferative phase (days 6-14)
- secretory phase (days 15-28)
53
what happens during the menstrual phase?
the uterus sheds the stratum functionalis, resulting in menstruation
54
what happens during the proliferative phase?
a new stratum functionalis develops with endometrial glands and spiral arteries and veins q
55
what happens during the secretory phase?
the spinal arteries convert the stratum functionalis to secretory mucosa and endometrial glands secrete uterine milk
56
what hormone is released if fertilization takes place? what is a major impact of this?
- human chlorionic gonadotropin (hCG)
- keeps the corpus luteum from degenerating and the progesterone level high
57
what changes occur in females during the secual response?
- vaginal mucosa, vestibule, and breasts engorge with blood
- clitoris and nipples become erect
- increase activity of vaginal mucosa lubricates the vestibule
58
what occurs during orgasm in females? do females have a refractory period?
- uterus exhibits peristaltic waves of contraction, and the cervix pushes down somewhat into the vagina
- not required for conception
- NO!
59
what hormonal changes occur during puberty?
- levels of estrogen and progesterone increase dramatically
- GnRH levels increase
60
list some female secondary characteristics.
- pubic and axillary hair
- increase in overall amount of adipose tissue in the subcutaneous layer, with additional deposits in the breasts, hips, and thighs
- increase secretions of sebacous glands
- skeletal changes: increased height and widening pelvis
61
what is menarche?
first episode of menstrual bleeding
62
what is female climacteric?
the time from the onset of irregular menstrual cycles to their complete cessation (may be up to 5 years)
63
what is menopause?
when menstruation has not taken place for at least one year
64
what changes in hormone levels occur during this time?
- low levels of estrogen and progesterone
- increased FSH and LH becuase they are no longer inhibited
65
what changes occur as a result of the chaging hormone levels?
- breasts, vagina, uterus, uterine tubes may shrink
- pubic and axillary hari may thin
- bone density decreases
- skin becomes thinner
66
why is sodium such an important osmotic particle in the ECF?
it is the most abundant extracellular cation
67
why is there such a steep sodium ion gradient between cytosol and ECF?
- the sodium-potassium pump
- the relatively low permeability of the plasma membrane to sodium ion
68
why is sodium critical to the function of excitable cells like neurons and muscle cells?
when sodium ion channels open, the sodium ions follow their concentration gradient and rush into the cell; causing depolarization
69
why is water balance dependent on sodium balance?
water reabsorption in the kidneys depends on a gradient consisting largely of sodium ions in the interstitial fluid
70
what two hormones increase sodium ion retention in the kidnes? how do they work?
- angiotensin-II: leads to increased sodium ion reaborption in the proximal tubule of the nephron
- aldosterone: releases from the adrenal cortex leads to increased sodium ion reabsorption from the distal tubules of the nephron
71
what hormones decreases sodium ion reabsorption?
ANP
72
what can cause a sodium ion imbalance?
anything that abnormally increases or decreases the number of sodium ions and/or the number of water molecules
73
why does the amount of water in the body affect the sodium ion concentration?
changes the concentration of sodium ions relative to water molecules
74
what is hypernatremia? what is the primary cause?
- sodium ion concentration in the blood above 145 mEq/L
- dehydration
75
what happens to cell in hypernatremia?
cells shrink
76
what are signs/symptoms of hypernatremia?
- dry mouth
- thirst
- dryness of skin
- decreased urine production
- fever
- organ function impaired
77
what is hyponatremia? what can cause hyponatremia?
- plasma sodium ion concentration less than 135 mEq/L
- overhydration OR hypersecretion of ADH
78
what are the signs/symptoms of hypoatremia?
- mental status changes
- seizure
- coma
79
how can hypoatremia be treated?
treated with hypertonic saline to restore the plasma sodium ion concentration and draw water back out of the cells
80
why is the steep concentration gradient of potassium ions critical to the function of neurons and muscle cells?
movement of potassium ions out of the cell down their concentration gradient through potassium ion channels is responsible for the repolarization phase of AP
81
what pump helps maintain the concentration gradient of potassium ions?
sodium/potassium pump
82
potassium ions are criticla in maintaining the ________________ potential
resting membrane
83
if potassium ion levels are critical, then why do you not die when you eat a banana?
due to deveral mechanisms including: insulin, aldosterone, and epinephrine
84
what hormone triggers the secretion of potassium?
aldosterone
85
what is hyperkalemia?
a plasma potassium ion concentration about 4.5 mEq/L
86
what happens to the RMP with mild/moderate hyperkalemia?
altered (more positive): the excess of potassium ions in the ECF causes fewer potassium ions to leave the cell
87
what happens with more severe hyperkalemia?
becomes so depolarized at rest that the cells are no longer excitable
88
what can cause mild hyperkalemia?
- renal failure
- aldosterone insufficiency
- widespread tissue damage due to severe burns or trauma
- drugs
89
what can cause severe hyperkalemia?
- ingestion
- administration of excess potassium ions
90
why are calcium and phosphate ions discussed together?
- they are found together in hydroxyapatite crystals
- inorganic portion of bone cannot be built unless both ions are present
91
simply put, what happens when the level of calcium ions in the ECF falls?
- calcium ions are released from the bone by osteroclasts
- more are reabsorbed from the flitrate in the kidneys
- more reabsorbed form ingested food and liquids in the small intestine
92
what happens when the level of calcium ion in the ECF rises?
- calcium ions are deposited into bone by osteoblasts
- fewer are reabsorbed from the filtrate
- fewer are absorbed from the small intestine
93
what two hormones regulate calcium and phosphate ion levels? what is the function of theses hormones?
- parathyroid hormone: triggers osteoclasts activity and calcium ion reabsorption in the kidneys; decreases reabsorption rate of phosphate ions; activation of vitmain D3
- vitamin D3 (calcitriol): potent stimulator of calcium ion absorption by the small intestine. increased osteoclast activity and calcium ion reabsorption from the kidney; triggers absorption of phosphate ions from the small intestine
94
what is hypercalcemia? what can cause hypercalcemia?
- a plasma calcium ion concentration above 10.5 mg/dL
- hyperparathyroidism, certain cancers, excess vitamin D, certain bone disorders, renal failure
95
what impact does excess calcium ions have on depolarization? why?
- diminsihes the ability of the neurons to depolarize
- because it makes neurons less permeable to sodium ions
96
what are signs/symptoms of hypercalcemia?
- decreased appetite
- constipation
- kidney stones
- bone pain
- frequent urination
97
what is hypocalcemia? how does this impact neurons?
- plasma calcium ion concentration lower than 8.7 mg/dL
- the neurons become hyperexcitable
98
what are some signs and symptoms of hypocalcemia?
- carpopedal spasm
- excessively long and strong muscle contractions
- sustained contractions
99
what are some important functions of chloride ions?
production of hydrochloric acid; secretion of bricarbonate ions from erythrocytes
100
chloride ion regulation is couple to the regulation of what other ion?
sodium
101
what is the pH range of body fluids, including blood?
7.35-7.45
102
what is a buffer?
resists changes in pH; prevents large changes in pH when an acid or base is added
103
what is a chemical buffer system?
chemical systems that work to buffer fluids in the body
104
what is a physiological buffer system?
functions of organ systems that work to buffer fluids
105
what are two physiological buffer systems?
- urinary system
- respiratory system
106
what are the two catergories of sources of acids adn bases in the body?
- those formed as a normal part of metabolic processes
- those ingested as part of the diet
107
what is the biggests source of metabolic acids?
carbon dioxide
108
do the acids and bases we consume in our food have a big impact on pH homeostasis?
no - they represent a very small minority
109
what assertion have been made by proponents of the alkaline diet?
- we all have blood that is too acidic due to out diets, and acid causes inflammation which causes disease
- alkaline diet is the core for every disease, up to and including cancer
110
is there any truth to these assertions?
- not really
- only that an alkaline diet would kill cancer cells
111
what is a strong acid?
acid that releases most of its hydrogen ions when placed in water
112
what is a weak acid?
- releases relatively few hydrogen ions in a soluton
- small impact on pH
113
what is a strong base?
binds and removes a great number of hydrogen ions from the solution
114
what is a weak base?
binds relatively few hydrogen ions in solution
115
which of these are found in a chemical buffer system?
weak acid and weak base
116
how does this minimize pH changes?
- weak base binds released hydrogen ions (from strong acid) and removes them from solution
- weak acid releases hydrogen ion to bind to released base ions (from strong base)
117
what is the equation for the carbonic acid-bicarbonate ion buffer system?
CO2 +H20 -- H2CO3 -- HCO3- + H+
118
what happens if a strong acid is added to a solution of pure water?
acid immediately donates its hydrogen concentration and therefore reduces its pH
119
what happens if a strong acid is added to a buffered solution?
hydrogen from the strong acid is accepted by the bicarbonate ion, forming carbonic acid
120
what happens if a strong base is added to a solution of pure water?
released hyroxide ions remove many of the hydrogen ions from the solution and increases its pH making it very basic
121
what happens if a strong base is added to a buffered solution?
- releases bicarbonate and hydrogen ions into the solution
- hydrogen binds to the hydroxide ion released from sodium hydroxide, forming water and a molecules of sodium bicarbonate
122
normally the amount of carbon dioxide expired is the same as the amount of ___________________
carbon dioxide produced by metabolic reactions
123
why does your respiratory rate increase when you are exercising and decrease when you are sedentary?
- exercising: glycolytic catabolism and oxidative catabolsim occur more rapidly and more CO2 is generated
- sedentary: you generate less CO2 so your respirate rate decreases
124
what happens to hydrogen and bicarbonate ions that are formed in the reaction above?
- hydrogen bind to hemoglobin, which buffers the cytosol of erythrocytes
- bicarbonate: transported into the plasma, where they buffer fixed acids
125
what are the two basic ways that the kidneys aid in acid-base balance?
- kidneys can excrete fixed acids that the lungs cannot excrete
- control the concentration of bicarbonate ions in the blood
126
the kidneys remove hydrogen ions by the process of ___________________ in the proximal tubule
secondary active transport
127
what percentage of bicarbonate ions are typically reabsorbed?
100%
