Physiology Flashcards
What is the process of producing sperm called?
Spermatogenesis
What is the process called where the spermatic becomes a mature spermatozoon (looses cytoplasmic contents and gains an acrosomal cap)?
Spermiogenesis
How long does spermatogenesis take?
2 months
Where does spermatogenesis occur?
Seminiferous tubules
What are the different types of sperm cells from spermatogonia to spermatozoa?
- Spermatogonium (2n 2C)
- Primary spermatocyte (2n 4C)
- Secondary spermatocyte (1n 2C)
- Spermatid (1n 1C)
- Mature spermatozoa
What happens when the spermatogonia turns into primary spermatocyte?
- Replicates (interphase) 2C -> 4C
- Travels through the tight junction (blood-testis barrier)
What process happens to turn the primary spermatocyte into the secondary spermatocyte?
Meiosis I
- Diploid to Haploid
What happens to turn the secondary spermatocyte into a spermatid?
Meiosis II
- Essentially just mitosis but in a haploid cell (1n, 1C) cell created
What happens when the spermatid matures into a spermatozoa?
Looses cytoplasmic contents and gains an acrosomal cap
How does Kartagener syndrome affect fertility?
- Tail mobility impaired -> infertility
How does Cystic fibrosis cause infertility in men?
Vas deferens is absent
Where are the different types of estrogen produced?
- Ovary = 17Beta-estradiol
- Adipose tissue = Estrone
- Placenta = estriol
Name the different types of estrogen from most to least potent?
Estradiol > Estrone > Estriol
What cells does LH act on in females?
Theca cells
What does LH stimulate the conversion of in the theca cells?
- Stimulates Desmolase through cAMP
- Desmolase converts cholesterol into androstenedione
What cells produce GnRH?
Arcuate nucleus and pre-optic nucleus
What are the stages (different cells) of oogenesis?
- Oogonium
- Primary Oocyte
- Secondary Oocyte
- Ovum
What stage of oogenesis does FSH stimulate?
Primary to secondary follicle
What stage of oogenesis is arrested for years and is completed during ovulation?
Prophase of Meiosis I
- Primary oocyte (2n, 4C) to Secondary oocyte (1n, 2C)
What stage of oogenesis is arrested until fertilisation?
Metaphase II of meiosis II
- Secondary oocyte (1n, 2C) into Ovum (1n, 1C)
What are the effects of FSH on the follicle?
- Primary follicle to Secondary follicle
- Stimulates the production of multiple layers of granulosa cells
- Stimulates formation of zona pellucida
- Conversion of androstrenedione to estrogen in granulosa cells
- Follicular fluid production in secondary follicle
The secondary oocyte is in what type if follicle?
Graffian follicle
- Primary oocyte in primary and secondary follicles
What are the structures called that do not become the ovum?
Polar bodies
What hormone causes an increase in temperature in women during ovulation?
Progesterone
What structure produces progesterone?
Corpus luteum
What are the functions of progesterone?
- Stimulation of endometrial glandular secretions and spiral artery development
- Production of thick cervical mucus (inhibiting sperm entry)
- Prevention of endometrial hyperplasia
- Increases body temp
- Decreases estrogen receptor expression
- Decreases gonadotropin (LH, FSH) secretion
During pregnancy
- Maintains pregnancy
- Decreases myometrial excitability (decreasing contraction frequency and intensity)
- Decreases prolactin action on breasts
What are the 2 phases of the menstrual cycle?
- Follicular phase
- Luteal phase
What are the effects of estrogen on LH ?
- Low concentrations of estrogen inhibit LH secretion
- At high concentrations it stimulates LH secretion
What is the FSH level negatively correlated with?
- Increased estrogen causes decreased FSH
What does the corpus luteum produce?
- Progesterone
- Inhibin
- Estrogen
What does the corpus luteum become?
Corpus albicans
What does inhibin produced by the corpus luteum act as?
Decreases FSH as not needed in luteal phase
How does a degraded corpus luteum result in menses?
Corpus luteum produces progesterone
- Progesterone maintains endometrium
- Decreased progesterone results in endometrium degrading -> menses
Why is progesterone higher in luteal phase than in the follicular and why are estrogen levels maintained in the luteal phase?
Corpus luteum produces progesterone (and estrogen)
How does degradation of the corpus luteum cause the menstrual cycle to restart?
Corpus luteum produces progesterone -> progesterone inhibits GnRH
- Degraded corpus luteum results in decreased progesterone thus the GnRH will rise
- Increased GnRH will result in higher LH and FSH ->
What is Mittelschmerz? What is it classically associated with?
Transient mid-cycle ovulatory pain
- Associated with peritoneal irritation (e.g follicular swelling/rupture, fallopian tube contraction)
What may Mittelschmerz be mistaken as?
Appendicitis
What hormone levels decreasing after delivery causes an increase in prolactin?
Falling estrogen and progesterone levels causes prolactin to increase
What does gravida indicate?
Number of pregnancies
Twins = 1 pregnancy
What does para indicate?
Number of pregnancies that resulted in live births
Birth of twins = 1 para
After how long is hCG detectable in the blood?
1 week after fertilization
After how long is hCG detectable in the urine?
2 weeks after fertilization
What is the difference between gestational and embryonic/developmental age?
Gestational - last period
Embryonic - time since fertilization
How does pregnancy affect the cardiovascular system?
- Decreased afterload (SVR)
- Increased blood volume (preload)
- Increased Cardiac output
- Hemodilution - decreased oncotic pressure -> peripheral edema
How does pregancy affect glucose levels?
- Insulin resistance and hypoglycemia
- Increased lipolysis and fat utilization (to preserve glucose and amino acids for fetus)
How does pregnancy affect the pituitary?
Enlargement - lactotroph hyperplasia
As pregnancy progresses how does this affect the levels of the female reproductive hormones?
- Human placental lactogen
- Prolactin
- Progesterone
- Estrogen
Levels of what globulins are increased in pregnancy?
- Thyroxine binding globulin
- Sex hormone binding globulin
- Corticosteroid binding globulin
How does pregnancy affect the GI system?
- Decreased GI motility
- Constipation
- Decreased LES tone -> GERD
- Gallblader stasis -> stones
What aare the hematological affects of pregnancy?
- Dilutional anemia (increased plasma volume) (there is also an increase in RBC mas but not in proportion)
- Hypercoagulable state (decrease blood loss at delivery)
- Iron and folate deficiency as micronutrient requirements increase
How does pregnancy affect the msk system?
- Lordosis (realigns centre of gravity)
- Joint laxity (facilitates fetal descent)
How may pregnancy affect the skin?
- Hyperpigmentation (melasma, linea nigra, areola darkening)
- Striae gravidarum (stretch marks)
- Vascular -> spider angiomas, palmar erythema, varicosities
How does pregancy affect the renal system?
- Vasodilation -> Increased renal plasma flow -> Increased GFR -> Decreased BUN and creatinine.
- Mild glucosuria and proteinuria
- Ureter and pelvis dilation (hydroureter, hydronephrosis) -> pyelonephritis
How does pregnancy affect the respiratory system?
- Chronic hyperventilation -> to eliminate fetal CO2
When does the luteal-placental shift become complete?
8-10 weeks of gestation
- Corpus luteum has degenerated and the placenta can now make all the estriol and progesterone
What subunit in hCG is identical to LH, FSH and TSH?
alpha subunit
What subunit is unique to hCG and is detected by pregancy tests?
Beta subunit
When is hCH increased?
- Multiple gestations
- Hydatidiform mole
- Choriocarcinoma
- Down syndrome
When can hCG be decreased?
- Ectopic pregnancy
- Edwards syndrome
- Patau syndrome
What is the function of human placental lactogen (aka chorionic somatomammotropin)?
- Stimulates insulin production
- Increases insulin resitance overall
- Gestational diabetes can occur when the pancreatic function cannot overcome the insulin resistance
What is the Apgar score?
How many points are in the scale?
Assessment of newborn vital signs following delivery
- 10 point scale
What are the different aspects of the apgar score?
- Appearance (pink=2, extremities blue = 1, blue or pale = 0)
- Pulse (>100, <100, no pulse)
- Grimace (cries and pulls away, grimices or weak cry)
- Activity (active movement, arms and legs flexed, no movement)
- Respiration (strong cry, slow irregular cry, no breathing)
What birth weight is defined as a low birth weight?
< 2500g
How does prolactin affect reproductive function?
Decreases reproductive function
What are the functions of oxytocin?
- Milk letdown
- Uterine contractions
What does breast milk contain (in regards to immune)?
- Immunoglobulins (mostly IgA)
- Macrophages
- Lymphocytes
How can breast milk benefit the child?
- Reduces infant infections
- Decreased risk of developing asthma, allergies, diabetes and obesity
What are supplements are exclusively breastfed infants recommended?
- Vit D
- Iron
What cancers are at a reduced risk after breastfeeding?
Breast and ovarian cancers
How is menopause diagnoses?
Amenorrhea for 12 months
Why is there a decrease in estrogen in menopause?
Decline in number of ovarian follicles
When is the average age of onset of menopause?
51 years (earlier in tobacco smokers) - Usually preceded by 4-5 years of abnormal menstrual cycles
Where is the source of estrogen after menopause?
Peripheral conversion of androgens -> estrone
What hormone specifically is greatly increased in menopuase?
FSH (as no follicles to stimulate)
- LH and GnRH also increased
What are the symptoms of menopause?
HAVOCS
- Hot flashes
- Atrophy of vagina
- Osteoperosis
- Coronary artery disease
- Sleep disturbances
What does meopause before the age of 40 indicate?
Primary ovarian insufficiency (premature ovarian failure)
- Often due to either chemo or radiotherapy
What is the androgen produced by the adrenals called?
Androstenedione
What are the functions of DHT?
- Differentiation of penis scrotum and prostate
- Later - prostate growth, balding, sebaceous gland activity
Describe the Tanner stages in men?
Stage 1 - No sexual hair Stage 2 - Pubic hair appears - Testicular enlargement Stage 3 - Coarsening of pubic hair - Penis size/length increases Stage 4 - Coarse hair across pubis sparing thigh - Penis width/glans increases Stage 5 - Coarse hair across pubis and medial thigh - Penis and tested enlarge to adult size
Describe the Tanner stages in women?
Stage 1
- No hair
- Flat appearing chest with raised nipple
Stage 2
- Pubic hair appears
- Breast bud forms (thelarche), mound forms
Stage 3
- Coarsening of hair
- Breast enlarges
Stage 4
- Coarse hair across pubis
- Breast enlarges, raised areola, mound on mound
Stage 5
- Coarse hair across pubis and medial thigh
- Adult breast contour + areola flattens
When is precocious puberty defined?
Appearence of secondary sexual characteristics before 8 in females and 9 in males
What sort of stature do people who go through precocious puberty have?
Short (due to the early closure of epiphyseal plates)
What is central precocious puberty?
Due to increased GnRH secretion
- Usually idiopathic
- May be due to CNS tumors
What can peripheral precious puberty be due to?
- Exogenous steroids
- Congenital adrenal hyperplasia
- Estrogen secreting ovarian tumor (granulosa cells)
- Leydig cell tumor
- McCune-Albright syndrome
When does puberty usually finish?
> 15 years
What are the different types of follicle?
- Primordial
- Primary
- Secondary
- Graafian
Progesterone suppresses the levels of what hormone?
GnRH
How common is spontaneous abortion?
1/4 pregnancies
- Miscarriage of fetus (20 weeks before gestation)
