Mod 5 Gonads and other organs Flashcards
What are gonads?
- testes in males
- ovaries in females
- produce steroid hormone and gametes (sperm and egg)
Order?
Hypothalamus –> GnRH (via Blood) –> Ant. pit (LH and FSH) –> gonads (sex hormone) –> target cells
What is testosterone?
Testosterone is a male reproductive anabolic steroid.
Testosterone plays a key role in the development of male reproductive tissues such as testes and prostate, as secondary sexual characteristics such as increased muscle and bone mass, and the growth of body hair.
What is testosterone produced by?
Testosterone is produced by Leydig cells in testes, located in the scrotum outside male pelvic cavity
What is a steroid hormone?
A steroid hormone is a lipid-soluble hormone, which modifies gene activity
What does testosterone target and action?
Testosterone is involved in spermatogenesis and descent of testes. Also, involved in growth and maturation of reproductive organs.
Targets: libido, anabolic effects (bone, Sk.M), and sebum and hair growth
Action:
Hematopoiesis: production of blood cellular components, enhances basal M.R and aggressiveness
Testosterone note
testosterone is converted to another steroid to some target organs. (prostat, brain bone)
What is the hypothalamic-pituitary-gonadal axis process in males?
1) Hypothalamus releases GnRH
2) The anterior pituitary secretes FSH and LH
3) FSH indirectly stimulates spermatogenesis
4) LH stimulates Leydig cells to secrete testosterone
5) testosterone acts at other sites (maturation of sex hormones, 2ndary sex characteristics, libido)
6) testosterone inhibits the release of FSH< LH and GnRH
7) inhibit released by Sertoli cell inhibits the release
What are gonads (ovaries)
- located in the female pelvic cavity
- each ovary contains many ovarian follicles, each follicle consists of an egg (oocyte) surrounded by layer of cells
- follicles vary is size and development exists at any time
- 1 dominant follicle releases an oocyte from ovary
(older) - scarred and pitted surface of ovary
what are the hormones that the ovaries produce?
The ovaries produce estrogen and progesterone for female reproduction development and 2ndary sex characteristics
Where are these females hormones produced?
produced by developing follicle (estrogens) and corpus luteum (estrogen and progesterone) in ovaries
What are estrogen and progesterone?
estrogen and progesterone are steroid hormones, they are lipid-soluble and they modify gene activity
What do estrogen and progesterone target?
- oogenesis and ovulation (estrogen)
- growth and maturation of the reproductive hormones and breasts
- established and regulate ovarian and menstrual/uterine cycles
What are estrogen and progesterone actions?
estrogen and progesterone actions consist: of the production of cervical mucus, libido (estrogen), anabolic effects including bone growth, fat deposition and feminization of the pelvis
- cardioprotective (estrogen), elevates body temp. in pregnancy, it prepares the uterus and glands
What are the steps of the establishment of the ovarian cycle?
- before puberty, ovaries secrete some estrogens which inhibit GnRH, after puberty the hypothalamus is less sensitive to estrogens so gonadotropin (FSH and LH) increase which promotes oogenesis
The regulation of the ovarian cycle
Follicular: (d1-14): FSH and LH promote survival and growth of follicles ( to make estrogen)
Ovulation: LH surge triggers rupture of dominant follicle and oocyte release
Luteal (d14-28): ruptured follicle forms corpus luteum, making progesterone and estrogen
What happens if there is no pregnancy?
the corpus luteum degenerates
What happens if there is a pregnancy?
in pregnancy, the corpus luteum persists until the placenta takes over
Ovary process summary
- menstrual (uterine cycle)
- cyclic changes to uterine lining in response to ovarian hormones
- coordinated with ovarian cycle (controlled by gonadotropins LH and FSH)
what occurs in infertility and early preg. loss?
- a hormonal imbalance ( infertility is the inability to conceive after 12 months)
- main causes are ovulation disorders, semen abnormalities, and tubal disease
What is anovulation?
A decrease in body fat, obesity, low ovary reserve), luteal phase defect- corpus luteum insufficient and a decrease in progesterone
What is amenorrhea?
excessive exercise, low body fat, no periods, stress)
What are other imbalanced
- hyperprolactin (excesses milk)
and there may be a decrease in sperm quantity and quality (Damage to DNA)
What does the placenta secrete?
temp. endocrine organ and secretes several hormones that sustains pregnancy –> estrogen, progesterone and human chorionic gonadotropin (hCG)
What does the adipose secrete?
Leptin targets the CNS neurons to promote satiety and decrease in appetite and eating.
What does the GI tract secrete?
It secretes various types of peptide proteins –> target areas of digestion
What does the heart secrete?
the atrial natriuretic peptide (ANP) it targets adrenal cortex to inhibit aldosterone, therefore produces a decrease in blood volume and pressure
What do the kidneys secrete?
the kidneys secrete erythropoietin (EPO) targets the bone marrow for red blood cell production (renin apart of RAAS)
What does the skeleton secrete?
osteocalcin, it targets the pancreas to secrete insulin and increase insulin sensitivity
What does the skin epidermis do?
The skin epidermis has cholecalciferol (inactive vit. D) modified in the liver and fully activated in kidneys.
