Quest 4 Flashcards
1
Q
Tonic and Surge Center
A
- Tonic center (flat line)
- allows basal concentration of GnRH to fetus at all times - Surge Center
- follows basal concentration of GnRH and peaks
2
Q
Puberty
A
- sexual maturation (ability to successfully reproduce)
- need:
1. Gamete production
2. Steroid Hormones
3. Development of Reproductive Tissue - since puberty is a gradual process, it is necessary to have fully functional GnRH neurons
- so, must produce a sufficient amount of GnRH (GnRH prod LH and FSH)
3
Q
Morula
A
- all cells have totipotency
- is cleaved, so you can not tell how many cells (ball of cells)
- will become a blastocyst
4
Q
Path to produce estradiol in males
A
- all steroid hormones begin at cholesterol
1. Cholesterol
2. Progesterone
3. Testosterone
4. Estradiol
5
Q
Sex vs Gender
A
- Sex- chromosomes
2. Gender- you (what you identify as)
6
Q
Reproductive Organ Development in males
A
- Germ cells migrate from yolk sac to genital ridge
- Causes proliferation of connective tissue (mass growth)
- Results in the formation of primitive sex cords
- will eventually become seminiferous tubules(1) in the male - Testis Enlarge and begin to press against the kidneys
- – beg at about 10-15mos gestation - The paramesonephric ducts begin to regress
- Retain the mesonephric tubules and they become the efferent ducts(3)
- Mediastinum(2) forms and is a connection point for the seminiferous tubules
- Development of mesonephric duct
- Mesonephric duct gives rise to the epididymis(4) and ductus deferens(5)
- testosterone supports these - Gubernaculum grows as testis get closer to the scrotum (drags testis deep into scrotum)
- There are forces at work to pull and push down testis through peritoneal layers
- Once testis is through the inguinal ring, the gubernaculum will shrink because the job is complete (50-75% of gestation)
* Gubernaculum depends on testosterone
7
Q
Define Differentiation
A
- the process where a group of unspecialized cells develop into recognizable groups of cells that have a common function
8
Q
3 Secretion Patterns of Hormones
A
- Tonic, Basal
- Pulsatile, Surge
- peaks about every 20 days - Sustained
ex: pregnancy when progesterone remains high
- will see all 3 patterns in females
- will only see tonic, basal pattern in males
9
Q
Surge Center in Males
A
- do not need surge center, so need to get rid of it
- Defeminization of brain(gets rid of surge center)
- need testosterone in order to convert it to estrogen/estradiol which will destroy the surge center
10
Q
Signs of Puberty
A
- Males
- reproductive behavior
- secondary sex characteristics
- first sperm seen in ejaculate
- when large number of sperm seen in ejaculate - Female
- reproductive behavior
- secondary sex characteristics
- first estrous cycle (in heat)
- first ovulation
- when pregnancy paired successfully without deleterious effects
11
Q
Endocrinological Study
A
- performed a common endocrinological study of ablation/replacement
1. Dr. Alfred Jost - studied rabbits
- extracted the uterine horn and took the fetus out of the uterus
- Gonadectomized(castrated) the fetus before it developed into a sex
- the rabbit defaulted to female
2. Natalie Josso - discovered that the rabbit developed female because of the extraction of the testis
12
Q
Allantois sac
A
- connected to yolk sac of embryo
- waste
13
Q
Development Sequence of Organs in male
A
- Seminiferous Tubules
- Mediastinum
- Efferent Ducts
- Epididymis
- Ductus Deferens
14
Q
Mammal Chromosomes and Bird Chromosomes
A
- Mammals
- xy = male
- xx = female - Birds
- zz = male
- zw = female
15
Q
Environments Role in the development of hypothalamic GnRH in the female (or onset of puberty)
A
- stress can delay estrous cycle
- light (day length), in horses longer days activate reproduction, in sheep longer nights(dark) activates reproduction
- Social Environment
1. 5 females and 1 male - will be more reproductively active in presence of male
2. 10 females- estrous cycles can link up
3. 5 females
16
Q
Factors that impact the development of hypothalamic GnRH in the female (or onset of puberty)
A
- Environment
- Plane of Nutrition
- Genetics