Renal Physiology Flashcards
1
Q
How is the testis connected to the prostate gland?
A
Epididymis, vas deferens
2
Q
What is connected to the prostate gland?
A
Vas deferens, urinary bladder, ampulla and seminal vesicles
3
Q
Why is the testis housed inside the scrotum?
A
To maintain the core temperature; the change in temperature can damage the production of sperm
4
Q
How is the descent of the testes (include timeline)?
A
3 months: above the inguinal canal (inside the body)
7 months: below the inguinal canal (inside the body)
Birth: outside the body
5
Q
What tubules is contained in the testes?
A
Seminiferous tubules (produce sperm)
6
Q
When does spermatogenesis begins?
A
Puberty
7
Q
What’s the difference between a normal seminiferous tubules and someone affected by mumps?
A
The person affected by mumps have lower spermatogenic cells and are more hollow (seminiferous tubule)
8
Q
What are the 3 cells in the testis and their function?
A
Leydig cells (interstitial cells)- secrete testosterone Sertoli cells (epithelial cells)- support sperm development Myoid cells (smooth muscle)- peristalsis to propel sperm
9
Q
What is the importance of blood-testis barrier and what is involved (junction and compartments)?
A
To protect the sperm from chemicals.
- Tight junctions
- Luminal compartment
- Basal compartment
10
Q
What are the 8 functions of Sertoli cells?
A
- Support sperm development: “trophic role”
- Secrete luminal fluid in for sperm housing
- Secrete androgen-binding protein
- androgen buffer
- helps maintain steady [androgens] in lumen
- Act as target cells for testosterone and FSH
- secrete paracrine factors that stimulate spermatogenesis
- Secrete inhibin
- hormone of negative feedback loop for FSH
- Secrete paracrine factors that affect Leydig cell function
- Phagocytosis of old and damaged sperm
- Site of immunosuppression (blood testis barrier)
11
Q
How does Sertoli cells know when to secrete inhibin?
A
When the hormone-producing cell in the anterior pituitary secrete hormone to Sertoli cells, it secretes inhibin
12
Q
What is the function of epididymis?
A
Maturation of sperm, storage site of sperm
13
Q
What is the function of vas deferens?
A
Conduit, storage site for sperm
14
Q
What does childhood to onset of adolescence mean?
A
The inability to reproduce hormones
15
Q
When puberty starts, what happens in males?
A
- Sexual maturation
- Reproductive organs mature
- Secondary sexual characteristics develop
16
Q
How does the production of male hormone occur in the Leydig cells?
A
Cholesterol > Pregnenolone > Progesterone > Androgens (testosterone)
17
Q
What are the 4 products that the testosterone can be converted to?
A
- Testosterone
- Di hydro testosterone
- Estrogen
- Inactive molecules
18
Q
How does the release of testosterone occur?
A
Higher centres stimulates the hypothalamus to release Gonadotropin-releasing hormone (GnRH) to the anterior pituitary. Anterior pituitary releases LH to Leydig and FSH to sertoli. Leydig cells releases testosterone. Testosterone sends a negative feedback to the hypothalamus and anterior pituitary.
19
Q
What are the key secondary sexual characteristics in males?
A
Pubic hair grows and genitals develop; increased body hair on limbs and torso; beard grows; voice breaks; growth spurt
20
Q
What are the 6 effects of androgens in males?
A
- Stimulate spermatogenesis
- Promote development of secondary sex characteristics
- Increase sex drive
- Promote protein synthesis in skeletal muscle (anabolic effect)
- Stimulate growth hormone secretion
- Promote development of male reproductive structures during embryonic life
21
Q
What’s the difference between mitosis and meiosis?
A
Mitosis ensures the continuous supply of spermatogonia while in meiosis the chromosome number becomes half
22
Q
Where does spermatogenesis occur?
A
Inside the seminiferous tubules in the space in between adjacent Sertoli cells (from basement membrane to lumen)
23
Q
What are the 4 main cells in the spermatid?
A
- nucleus
- mitochondria
- Golgi apparatus
- acrosomal vesicle
24
Q
How long does it take for spermatid to form a spermatozoa?
A
Approximately 24 days
25
What does the acrosomal vesicle develops into?
It develops into an acrosomal cap that is initially above the nucleus and then wraps the nucleus
26
What are the 3 sections of the sperm and what do they contain?
1. Head
-Nucleus: chromosomes
-Acrosome: enzymes necessary for fertilization
2. Midpiece
-Mitochondria: source of energy
3. Tail
Whiplike movements propel sperm
27
After spermatogenesis, what occurs?
The spermatozoa is released into lumen of seminiferous tubules and remains immobile for about 20 days
28
How does the sperm move to the epididymis?
Pressure generated by the fluid secreted from Sertoli cells pushes the sperm and fluid to the epididymis
29
What occurs in the epipdymis?
The sperm acquires motility and is concentrated. The sperm resides for about 6-12 days.
30
What does the gonadotripins stimulate?
- release the FSH (stimulate gametogenesis)
| - LH (stimulate androgen secretion)
31
How does the pulse generator work?
The pulse generator is at the onset of puberty; under the influence of higher brain centres (eg exercise, nutrition)
32
What’s the difference between the negative feedback of Sertoli cells and leydig cells?
The negative feedback of Sertoli cells only act on the anterior pituitary while the leydig cells act on both anterior pituitary and hypothalamus
33
What is the function of seminal fluid (in the seminal vesicle)?
1. Dilution of sperm
2. Provision of energy (fructose)
3. Formation of semen “clot”
34
Why is the seminal fluid alkaline?
To protect the sperm; fructose provide energy, enzymes also protect the sperm
35
What is the function of the prostate gland?
Secrete citrate and enzymes
36
What happens when there’s a hypertrophy in the prostate gland?
Bio marker for cancer
37
What is the function of PSA?
Act as an anti-clotting factor; breaks down semen clot such that the sperm can be freed and allowed to move
38
What is the function of bulbourethral gland?
Secrete viscous fluid with mucus
39
What are the 3 phases in the neural control of males and how are they controlled?
1. Erection - parasympathetic nervous system
2. Emission - sympathetic nervous system
4. Ejaculation
40
What are they key points of the parasympathetic control of erection?
Arteries supplying blood to erectile tissues > relaxation of smooth muscle > increase blood flow
41
What is the mechanism of vasodilation in erectile response?
Activation of parasympathetic nerve > increased nitric oxide > increase cGMP > vasodilation / inactive breakdown product > increase blood flow
42
What enzyme breaks down cGMP to lower its level?
Phosphodiesterase
43
What is the main function of viagra?
It inhibits phosphodiesterase so that cGMP levels cannot be lowered
44
What accounts for the low number of sperm to reach the site of fertilization?
- pH of female tract is acidic
| - sperm do not have enough energy
45
What is capacitation?
Sperm maturation in the female tract
46
What occurs during capacitation?
The sperm head goes through destabilization. The multiple fusion points fuse with the membrane of the acrosome. The acrosomal enzymes then are released.
Whiplashing of the tails occurs.
47
What are the 3 phases of the female reproductive activity?
1. Menarche - onset of puberty
2. Menstruation - female reproductive system cycles
3. Menopause - loses the ability to reproduce around 45-50
48
What is the function of the uterine tubes?
Transports ova form ovaries to uterus
49
What is the function of infundibulum and fimbraie?
Picks up released ovum
50
What is ectopic pregnancy?
The development of embryo in the uterine tube
51
What is the outer layer of the wall of the uterus and what is it made up of?
Perimetrium; epithelial cells and connective tissue
52
What is the middle layer of the uterus and what is it made up of?
Myometrium; smooth muscle
53
What is the inner layer of the wall of the uterus and what is it made up of?
Endometrium; epithelial cells, connective tissue and numerous glands
54
How is the egg developed in the ovary?
Immature follicles > maturing follicles > graafain follicle > release of egg
55
Typically what day is the egg release based on the ovulation cycle?
Day 14
56
How long is the follicular phase and luteal phase?
Follicular phase: 14 days
| Luteal phase: 14-28days
57
What are the 3 phrases of the uterine cycle and what is their timeline?
1. Menstrual phase: Day 1-5
2. Proliferative phase: Day 5-14
3. Secretory phase: Day 14-28
58
What are the stage in follicle growth?
- primordial follicle grow and forms the zona pellucida which forms the primary follicle
- granulosa cells multiplies and forms the preantral follicle
- early theca forms
- during the early antral follicle, the antrium is formed as well as the theca
- antrum and theca develops (mature follicle)
59
What initiates folliculogenesis?
FSH exerts mitosis effect on granulosa cells
60
What are the 2 effects of FSH?
1. Stimulate granulosa cell proliferation, produce estrogen and further growth of antrum
2. Increase aromatase synthesis and activity in granulosa cells and more E production
61
What receptors do thecal cells have?
LH receptors
62
What are the effects of estrogen?
1. Further growth of granulosa cells
2. Up regulate LH receptors on granulosa cells
3. Progesterone receptors on uterine endometrial cells
63
What is the difference in the granulosa during early and late follicle phase?
The granulosa produces progesterone from cholesterol
64
What are the 6 functions of granulosa?
1. Secrete antral fluid
2. Provide nutrients for developing locate
3. Secrete paracrine that support follicle development
4. Secrete inhibin
5. Secrete estrogen
6. Secrete substance that forms zona pellucida
65
What is oogenesis?
The conversion of oogonia to ova
66
Before puberty, what does the primary oocyte go through?
Meiotic arrest
67
When does mitosis, meiosis I, meiosis II occur?
Mitosis starts in the first 2 months of embryonic life.
Meiosis 1 begins in fetal life and becomes arrested at 7 month of fetal life.
Meiosis 2 completed after fertilization
68
When does 1st meiotic division complete?
In the dominant follicle at the time just prior to ovulation
69
What are the 5 stages of oocyte development?
Primordial germ cell > Oogonia > Primary oocyte > Secondary oocyte > Ovum
70
Why is there a small increase in LH and FSH during the early stage of menstrual phase?
The low levels of E and P removes the negative feedback of LH and FSH.
71
During the proliferative phase what hormone increases and decrease?
Increases: estrogen
Decreases: FSH
72
When does the LH and FSH peak?
Right before secretory phase
73
Why is there a decrease in FSH during the proliferative phase?
Due to the effects of inhibin and atresia of other follicles
74
Why is there an increase in progesterone and estrogen during the secretory phase?
To keep the corpus leuteum alive
75
What’s the difference in actions of the granulosa cells when FSH and LH is secreted?
FSH: inhibin secretion and oogenesis and follicular development
LH: Enzymatic modification of androgens > estrogen secretion
76
Why does LH and FSH decrease during the luteal phase?
This is due to the inhibitory effect of the progesterone
77
What are the 3 effects on the endometrial lining during the menstrual phase?
- shedding of uterine lining
- blood flow to tissue decreases
- tissues die and slough into vagina causing menstrual flow
78
What happens to the endometrial lining during the proliferative phase?
- endometrial lining develops > layer grows > glands enlarge
- smooth muscle layer thickens
- cervical gland secrete a thin muscus
79
What occurs in the endometrium during the secretory phase?
- blood supply increase
- glands enlarge and secrete glycogen-rich fluids
- cervical secretions more sticky forming a plug
80
What are the 4 phases that occur after fertilization (include their timeline)?
1. Embryo (first 2 months)
2. Fetus (after 8 weeks; 2 months)
3. Gestation (nine months)
4. Parturition (birth)
81
What is required by the sperm to be capable of fertilization?
Capacitation
82
Why is there only few hundred sperm make it to uterine tube (2 possible reason)?
1. Damage due to acidic pH of the female tract
| 2. Some loss due to leakage of cervix
83
Why is polyspermy not favored?
- only one male gamete can fuse with the female gamete to form a diploid chromosome
84
Explain the events of fertilization.
Many sperm binds to receptors on the zona pellucida and undergo acrosome reaction > sperm move through zona pellucida > ONE sperm binds to egg plasma membrane
85
How is polyspermy prevent?
Egg releases contents of secretory vesicles > enzymes enter zona pellucida > polyspermy blocked
In detail:
- change in membrane potential
- release of contents from cortical granules
- enzymes enter and harden zona pellucida
- enzymes inactivate sperm binding receptors
86
What are the two ways the zygote can begin embryogenesis?
1. Sperm drawn into egg > egg completes 2nd meiotic division > nuclei of sperm and egg unite
2. Egg enzymes activated
87
What is a morula?
When the female gamete totipotent up to 16-32 cell stage
88
How are identical twins occur?
Division of a totipotent morula cells
89
How are non-identical (fraternal) twins formed?
Fertilization of two oocyte (released during the same cycle) by two separate sperm
90
When is blastocyst formed?
4-5 days post fertilization
91
What is contained in the blastocyst?
Inner cell mass (becomes embryo), blastocoele and trophoblast (becomes fetal placenta)
92
What are the 4 stages of early embryonic development?
Zygote > early cleavage > morula > blastocyst
93
How does the blastocyst attach to the wall of the endometrial?
Sticky trophoblast cells
94
What occurs during the decidual response?
- syncytiotrophoblast converted from the fused trophoblast cell layer
- cytotrophoblast formed
- amniotic cavity formed in the inner cell mass
95
What is chorionic villus?
Finger-like projections of fetal blood vessels in the placenta
96
What are the 3 functions of the placenta?
1. Endocrine organ
- produces hormone
2. Exchange tissue
- respiratory gases, nutrients and waste products
3. Filter/immunological protection
97
Where is human chorionic gonadotropin released from?
Trophoblast
98
What are the 3 hormones involved in pregnancy?
Human chorionic gonadotropin (HCG), estrogen, progesterone
99
What are the 4 hormones of the placenta and their function?
1. Human chorionic gonadotropin (hCG)
Maintains corpus luteum functions in early pregnancy
2. Human chorionic somatomammotropin (hCS) or human placental lactogen (hPL)
GH-like and anti-insulin like actions in the mother ; helps the fetus to avail more glucose
3. Progesterone (steroid)
Decrease uterine contractions; inhibition of LH and FSH and inhibition of menstrual cycle; growth of mammary alveolar glands; secretes sperm unfriendly mucus
4. Estrogen (steroid)
Growth of uterus (myometrium); growth of mammary ducts; inhibition of LH and FSH
100
What are the effects of estrogen and progesterone on uterus?
```
Estrogen:
- contractile activity of smooth muscle
- responsiveness of oxytocin
Progesterone:
- suppression of contractile activity
- maintenance of secretory-phase conditions
```
101
What are the effects of estrogen and progesterone on AP?
```
Estrogen:
- prolactin secretion
- growth and development of breast tissue
Progesterone:
- none
```
102
What are the effects of estrogen and progesterone on breasts?
```
Estrogen:
- growth of duct tissue
- fat deposition
- suppression of lactation
Progesterone:
- growth of glandular tissue
- suppression of lactation
```
103
How is the control of parturition regulated?
Oxytocin secretion from posterior pituitary > strengthen uterine contractions (parturition) > pressure of fetus against cervix (positive feedback of oxytocin)
104
How is myometrial contractions increased and inhibited?
Increase:
Estrogen, prostaglandin, oxytocin, stretch
Inhibited:
Progesterone, relaxin
105
What is cervical ripening increased and inhibited by?
Increase:
Prostaglandins, relaxin
Inhibited:
Progesterone
106
What is cervical ripening?
Cervix go through enzymatic reactions so that the cervix gets relax to help pushing out the baby
107
What are the 2 sources of relaxin?
Corpus luteum and placenta
108
How does parturition occur?
Cervix ripens > dilation & uterine contractions > babies head wedges cervix open, head first > expulsion of placenta
109
What’s the difference between the mammary gland in at birth to puberty and puberty?
During puberty:
- ducts grow and branch out
- some alveolar growth
- deposition of fat and alveolar tissue
110
What are the 3 hormones that develops in the mammary gland during pregnancy?
- prolactin: lactogenesis
- hPL: growth factors
- oxytocin: required for milk ejection
111
What is galactopoiesis?
Process of maintenance of lactation
112
How does the suckling reflex helps in the projection of milk (hormone)?
The hypothalamus secretes PRH and decreases PIH to the anterior pituitary. This increase the release of prolactin secretion which causes milk secretion bu alveoli in breast.
113
How does the suckling reflex helps in projecting milk?
The hypothalamus increase activity in neurosecretory cells in the posterior pituitary. Increase oxytocin, contraction of myoepithelial cells in breast and milk ejection.
114
What is the jost paradigm?
Genetic sex (type of sex chromosome) > gonadal sex (type of gonads) > genital or phenotypic sex (type of internal and external genitalia)
115
What is bipotential gonad?
The gonad is the embryonic stage with the potential to develop into either the male or female reproductive organ
116
What is the Klineflter’s syndrome?
Male with XXY
117
What is Turner’s syndrome?
The lack of X chromosome (XO); born with streak ovaries
118
What are some of the characteristics of Klinefelter syndrome?
Taller than the average height, reduced facial hair, reduced body hair, breast development (gynacomastia), osteoporosis, feminine fat distribution, small testis
119
What are some of the characteristics of Turner’s syndrome?
Short stature, low hairline, fold of skin, shield shape thorax, poor breast development, brown spots, no menstruation, small fingernails, elbow deformity, rudimentary ovaries (uterus not developed, ovaries have ridges), constriction of aorta
120
What dictates the factors that differentiates males?
- Testes secrete Mullerian inhibiting hormone (MIH) from sertoli cells
- Testosterone (T) secreted from Leydig cells
121
What is the effect of MIH?
Regression of female internal gentalia
122
What is the effect of dihydrotestosterone (DHT)?
Masculinization of male external gentalia
123
What does the mullerian ducts develop into?
Uterus, oviducts, etc.
124
What does the wolffian ducts develop into?
Epididymis, vas & seminal vesicle
125
What is androgen insensitivity syndrome (CAIS)?
Mutation of androgen receptor
126
What are some of the symptoms of complete androgen insensitivity syndrome (CAIS)?
- Genotype 46 XY
- female external genitalia
- body female-like
- breast develop
- androgens are converted to estrogen in target tissues
- absence of ovaries and uterus, no menstrual cycles
- infertile
127
What is congenital adrenal hyperplasia?
Females that has ovaries but is outwardly “male”
128
How does congenital adrenal hyperplasia occur?
Decreased cortisol > increased ACTH > increased adrenal androgens > masculinization of external genitalia
129
What is meant by puberty?
Period during which a child becomes sexually mature
130
What triggers the onset of puberty?
Increased secretion of GnRH from pulse generator from AP > increased LH and FSH from AP > increased sex steroids from gonads > pubertal changes
131
What is climacteric?
Declining endocrinal, somatic, reproductive and psychological functions
132
When does climacteric starts in females and males?
Females:
Perimenopause
Males:
Andropause
133
What does perimenopause mean?
~1000 follicles
134
How does follicular depletion occur?
Apoptosis (atresia)
135
What hormonal changes happen in menopause in women?
Decreased estrogen, inhibin and progesterone removes negative feedback inhibition; FSH and LH levels increase
136
What are some of the physiological conditions of menopause?
Decreased follicle numbers, responsiveness of gonadotropins, ovulation becomes irregular, no ovulation, no corpus luteum
