Hormone Physiology Flashcards
Hormones that drive reproduction and growth
1.) GnRH (Gonadotropin Releasing Hormone)
2.) Gonadotropins FSH and LH
3.) Testosterone, Progesterone
Male Sexual function
1.) Begins at puberty
2.) develops male characteristics
3.) testosterone
Female Sexual function
1.) Begins at puberty
2.) estrogens
3.) progesterone
What is a gland?
Collection of cellular (epithelia) matter that “makes” a product (stuff in tissue)
Examples of glands
- salivary
- adrenal
- pituitary
- hypothalamus
- liver
- gonad
- sweat
- breast
Glands secrete or excrete, and we are primarily focusing on what type of glands?
Endocrine glands
Endocrine glands
HORMONES
- product enters bloodstream
- feel immediately (such as a fear response)
Exocrine glands
OTHER
- product enters duct or opening (doesn’t go through blood and affect whole body)
Examples of exocrine glands
- sweat
- milk
- tears
- digestive fluids
- mucus
What dictates what type of gland it is?
Where product is going
GnRH
Gonadotropin Releasing Hormone
GnRH is released by what?
neurons in the hypothalamus
GnRH functions
- regulator of reproductive axis (pulsing release)
- pulsatile secretion determines patter of secretion of FSH and LH from anterior pituitary gonadotroph cells
Gonadotropins FSH and LH come from what?
Anterior Pituitary Gonadotroph cells
FSH and LH function
Regulate endocrine function and gamete maturation in the gonads
Hypothalamus produces what?
GnRH
Anterior pituitary produces what?
FSH and LH
-travel to the gonads for gamete production
(Testosterone, progesterone, estrogen)
FSH
Follicle Stimulating Hormone
- aids in gametogenesis/spermatogenesis/oogenesis
LH
Luteinizing Hormone
- aids in ICSH interstitial cell stimulating hormone release
- release testosterone in males
- please estrogen & progesterone in females
(chemical change to know what to do)
What age do males begin puberty?
Between 10-14 (sperm production and secondary sexual characteristics)
At the beginning of male sexual life:
- Hypothalamus creates GnRH
- Anterior pituitary creates FSH and LH
(FSH aids in gametogenesis and spermatogenesis)
(LH aids in ICSH interstitial cell stimulating hormone, secrete testosterone
FUNCTION: helps with the growth of the testis (FSH) and male testosterone production
Develops Male Characteristics
1.) Formation of penis and accessory genitals (increase in size)
2.) Prenatally descends the testes
3.) Testosterone will remain dormant until puberty, then sexual desire will begin
4.) Genitalia size increases at puberty
Testosterone
Drives secondary sex characteristics
Secondary male characteristics
1.) Location of hair- facial, abdomen, chest, pubis, under arms
2.) Voice- thicker and longer voice chords
3.) Musculature- structure, placement, deposition of fat (more on chest, neck, abdomen), development of bone structure (os coxae bones are narrow and taller)
- more muscle protein
- making cells we already have bigger
When does puberty usually start in females?
10-14 (eggs dormant until puberty)
Menarche
Beginning of menstrual/female sexual life
At the beginning of female sexual life:
- Hypothalamus creates GnRH
- Anterior pituitary creates FSH and LH
(FSH aids in follicle/egg maturation; triggers the initial estrogen production at follicles via granular cells)
(LH follicle maturation; hormone trigger for ovulation, release of egg from ovary)
*Essentially egg is triggered, prepped for ovulation, and an egg is ovulated
Peaks and valleys of hormones during our 28 day menstrual cycle
If no implantation, peak of hormones comes back down
*every month the cycle repeats
Estrogens
1.) Helps with enlargement of the vagina, uterus, labia
2.) Triggers growth of hair (pubic area and under arms)
3.) Growth and development of breasts (mammary)
4.) Slows bone growth, ossifies epiphyseal growth plates (stature quicker than males because of pregnancy and don’t want the extra growing weight from stature adding extra stress to the body)
5.) Drives secondary sex characteristics
Secondary sex characteristics in females
1.) Location of hair- pubis and under arms
2.) Voice- shorter voice chords
3.) Deposition of fat (different than males because butt, thigh, boobs)
4.) Bone structure (wider pelvic angle)
Progesterone (implantation triggers its own hormonal flow)
1.) Released by corpus luteum (adrenals and placenta)
2.) Prepares oviduct and uterus for fertilized egg
3.) Helps fimbriated end of oviduct move to draw egg in
4.) Helps develop/thicken endometrium for fertilized egg (no egg, levels drop and you shed uterine lining) (to shed lining, we need contraction)
5.) Inhibits contraction of uterus (cramps)
6.) Postpartum (delivery)
- decrease triggers mammal glands milk secretion
- inhibits contraction of uterus pre/post
What is a gamete?
*A mature haploid (n) male or female germ cell which is able to unite with another of the opposite sex in sexual reproduction to form a zygote (2n)
- sex cell
- egg or ovum
- sperm
*Gametes are formed by meiosis
*Sexual reproduction
*Fertilization (aka the JOINING of the egg and sperm to make a ZYGOTE)
Spermatogenesis
Location is in Seminiferous tubules
Interstitial cells of Leydig produce testosterone
Spermatogonia- unipotent stem cell, self-renew, “primordial germ cell” (pathway to becoming sperm cells)
Spermatogenesis Steps of development
1.) Spermatogonia (2n) (mitosis…)
2.) 1 degree Spermatocytes (2n) (meiosis 1…)
3.) 2 degree Spermatocytes (n) (meiosis 2…)
4.) Spermatid (n)
5.) Sperm release at lumen (once mature)
Sertoli cells
NURSE CELLS/MOTHER CELLS
Location of Sertoli cells
Within seminiferous tubules
Sertoli cells function
1.) Nourishes developing cells
2.) Maintains blood-testes barrier (aka BP) (don’t want too high of blood pressure)
3.) Synthesizes Androgen-Binding Protein that maintains a high testosterone inside Sertoli cells
4.) Creates an environment for differentiation and maturation
5.) Target cells for FSH, have Rc’s for FSH, starts whole process
6.) Facilitates the release of new sperm
7.) Phagocytic- degrades residual cytoplasm during spermatogenesis (take in debris/junk leftover and digests it)
8.) Synthesizes Inhibin to control FSH, LH, and GnRH (to regulate hormone fluctuation)
3 parts of sperm cells
1.) head
2.) midpiece
3.) tail
head of sperm
contains DNA with nucleus
Acrosome: membrane bag filled with enzyme (very head of head; digests wall of egg and fertilization)
Midpiece of sperm
mitochondria and glucose for ATP production
Tail of sperm
(moving a long distance)
- second centrioles form flagella
- serpentine movement- flagellated
- microtubules (9+2)
- tubes are linked together by proteins and ATP breaks the cross-linkages between the doubles of microfilaments
- RER, SER, Golgi producing proteins, steroids, etc.
Oogenesis
Location: Ovary cortex
- Granulosa cells produce estrogen (1 degree)
- Theca cells produce androgens used for estrogen
- Corpus luteum produces progesterone (2 degree)
Oogonia+follices results in oocyte/ovum
Oogenesis steps of development
1.) Primordial follicle
2.) 1 degree vestibular follicle
3.) 2 degree vestibular follicle
4.) 3 degree follicle or Graafian follicle or Antral follicle (tertiary development)
Antral
space/area (less than 1m)
Follicle contains (what becomes the egg)
1.) Germinal vesicle
2.) Oocyte
3.) Granulosa cells
4.) Zona Pellucida
5.) Cumulus Oophorus
6.) “egg bearing heap”
Germinal vesicle
nucleus (DNA) of the egg
Oocyte
the egg and its cell membrane (egg cells)
Granulosa cells
- surround egg (like a halo)
- squamous cells that progress into cuboidal cells
- undergo great proliferation when follicle is maturing
- FSH communicates to these cells to “put” LH Rc’s on their surface, when LH binds proliferation of these cells stops
Zona pellucida (protection)
extracellular matrix produced by oocytes and other cells (clear)
Cumulus oophorus (with corona radiata!!!!)
all granulosa cells surround the follicle and egg after ovulation
“egg bearing heap”
Once a month until menopause, eggs go through these phases, release eggs, etc.
These eggs are stored in ovary until hormone fluctuation
Antrum
Fluid filled sac/space containing egg (2 degree)
Basal lamina
connective tissue (CT) and extracellular matrix, surrounding Zone Granulosum (halo)
(tissue layer surrounds outer shell of follicle)
Theca cells “box”
- beyond basal lamina
- promote oocyte maturation
- External layer: fibrous
- Internal layer: secrete androgens used by granular cells to make estrogen
- help to form Corpus Luteum and secretes progesterone
Primordial germ cell into primordial follicles
- OCCURS at 3-8 months gestation
- Fetal development: stem cells (2n) migrate to the ovary during fetal development
~ Here along the ovarian cortex border, the primordial germ cells undergo mitosis to give rise to 700K-2 MILLION oogonia (2n)
~ Soon, some of these oogonia will undergo Meiosis 1 through to prophase 1 and STOP (arrest, hibernation) and will result in close to 7 million 1 degree oocytes
“Stress breeds stress”
Exposure to stress or other factors as an egg puts you at higher risk for developing those conditions
Primordial follicle
Primordial germ cells at the ovary will have the generation of SIMPLE SQUAMOUS FOLLICULAR CELLS surrounding the oocyte thus now called the primordial follicle
- these simple squamous follicular cells will later enlarge to become simple cuboidal and be known as granular cells (which secrete estrogen)
- Granular cells, later in this follicle development (puberty) greatly populate in number
Puberty (slow and progressive process of growth and development)
Body size, BMI, and other factors triggers the brain to start puberty
- at this time, the hypothalamus secretes GnRH which in turn stimulates the Anterior Pituitary to release FSH and LH
~ The FSH stimulates the development of the follicles
- the granulosa cells have FSH Rc’s
~ the granulosa cells are stimulated to produce aromatase
- as the follicle grows, the Theca cells are formed
~ Theca cells are stimulated by LH to produce androgens that are converted by the aromatase into Estradiol (Estrogen)
~ Estrogens also help to mature the follicles
1 degree Follicle (1 degree Oocyte) (week 12-20, 3-5 months of gestation)
These surrounding follicular cells now enlarge to become simple cuboidal and are now known as granular cells. These granular cells form a halo around the oocyte, called the Corona Radiata
- The primordial follicles are stimulated into Meiosis 1 and PAUSE at prophase 1
- these cells are now known as 1 degree oocytes (follicles) (2n)
- here they will remain in a state of REST until puberty and ovulation cycles begin
- by puberty, only 400K 1 degree oocytes remain, the rest have deteriorated
Puberty
Body size, BMI, other factors triggers the brain to start puberty
- at this time, the hypothalamus secretes GnRH which in turn stimulates the Anterior Pituitary to release FSH and LH
- The FSH stimulates the development of the follicles (the GRANULOSA cells have FSH Rc’s)
- the GRANULOSA cells are stimulated to produce AROMATASE
- As the follicle grows, the THECA cells are formed
- THECA cells are stimulated by LH to produce androgens that are converted by the aromatase into Estradiol (ESTROGEN)
- Estrogens also help to mature the follicles
Body Mass Index (BMI)
height and weight for a body frame
Problems with hormones
Pediatrics: increased BMI
Dairy, milk estrogens
What is hiding in your glass of cow’s milk and what affect does it have on the body?
While the dairy industry focuses on marketing for cows’ milk without added hormones, they fail to mention the many natural hormones in milk, including estrogen and cortisol
- it is not normal for animals to drink milk after like age two, so lactase intolerance is the normal response and being able to digest lactase is the weird thing that has evolved as our culture relies more on milk in the food industry
Risks of natural estrogen in cows’ milk
Increases the risk of prostate, breast, uterine, and ovarian cancers
Cortisol in cows’ milk
Linked to stored belly fat and lowered muscle mass
1 degree –> 2 degree follicle (2 degree oocyte) (Ovulation, puberty+)
A surge in FSH and LH stimulates several (up to 50) follicles to mature to eggs. Within 15 hours of this surge, the 1 degree oocyte RESUMES meiosis 1 and the surrounding membrane breaks down
- By hour 20, meiosis 1 is complete and the 2 degree oocyte (n) + polar body is formed
- The 2 degree oocyte has a well defined nucleus, cytoplasm, Zona Pellucida, many Granulosa cells surrounding scattered antrum (opening that becomes bigger as you go), and Theca cells
*The Theca Interna and Theca External may be seen
Antrum
Nutrient fluid (in opening)
Zona pellucida
glycoprotein based extracellular matrix
Graafian follicle (3 degree oocyte) (Ovulation, Puberty+)
The (tertiary) Graafian follicle (haploid) is in the stage after Meiosis 1 division but BEFORE ovulation
- These are huge!!!
- A large fluid-filled follicular antrum is seen taking up most of the follicle
- The oocyte is surrounded by the Zona Pellucida –> then Corona Radiata (granular cells) and a stalk of granular cells known as the Cumulus Oophorus (egg bearing heap) extends to the Zona Granulosa (halo of granulosa cells)
- A Basal Lamina surrounds the Zona Granulosa which is then coated by the Theca Interna and Theca Externa
When released from the Graafian Follicle, it is considered…
Ovulated
- the ovum will contain the:
1.) oocyte
2.) Zona Pellucida
3.) Corona Radiata
What technology can be used to look at Graafian follicles?
Sonogram
- checks for cysts, etc.
Egg Cellular Life Boat
1.) Cytoplasm
2.) Organelles
3.) Sugars
4.) Lipids
5.) Proteins
- enzymes
- transcription factors (genetic information)
- FIRST transcription occurs with ovum proteins NOT male proteins, that’s later
Corpus Luteum (Post Ovulation +/1)
The ovum was released leaving behind the Zona Granulosa, Basal Membrane, and Thecal Layers
- Granular cells increase in size and become Glandular Granulosa Lutein cells
- Theca cells increase in size and become glandular Theca Lutein cells (produce PROGESTERONE)
Corpus luteum
Cells left behind that produce progesterone that helps with implantation
If NO pregnancy
Corpus luteum degenerates (14 days) into Corpus Albicans, levels of oestrogen and progesterone FALL
- This triggers release of FSH and LH from Anterior Pituitary and cycle begins again
(systematic feedback system)
If pregnancy
the fertilized ovum implants into the placenta, and the placenta releases it’s own hormones…
- HCG (Human Chorionic Gonadotropic hormone), and the corpus luteum persists releasing oestrogen and progesterone maintaining pregnancy
When testing to see if pregnant…
testing for HCG (Human Chorionic Gonadotropic) hormone
