Endocrine - Reproduction Physiology Flashcards
What pathway does sperm follow?
Seminiferous tubule
Epididymis
Vas deferens
Ejaculatory Duct
Nothing
Urethra
Penis
What accessory glands produce seminal fluid?
Seminal vesicles
Prostate
Bulbourethral glands
Semen is made up of…
Sperm + Seminal Fluid
Benign Prostate Hyperplasia (BPH)
Cells within the prostate gland proliferate making it larger.
Why do you think that difficulty initiating urination, slow urine flow, and feeling like the bladder is not emptied, are symptoms of BPH?
The enlarged prostate gland compresses the urethra decreasing urine flow and making it hard to initiate or continue peeing.
Identify the following structures:
- Penis
- Urethra
- Epididymis
- Testicle
- Prostate
- Seminal Vesicle
- Colon
- Bladder
- Vas deferens
Sperm are produced in the _ and mature in the _.
Sperm are produced in the seminiferous tubules and mature in the epididymis.
Testis Anatomy: Clinical Correlate
Intracytoplasmic sperm injection for male infertility: What is it?
Collect sperm from seminiferous tubules or epididymis
Incubate with egg
The seminiferous tubule contains what important structures/cells for sperm production?
Sertoli Cell
Capillaries
Leydig Cells (Interstitial Cells)
What is the function of sertoli cells?
They secrete proteins to support sperm production
Stimulated by testosterone
Help mature sperm cells
FSH receptors → produce ABG
Mature sperm are found…
Close to the lumen of the seminiferous tubule
Young sperm are found…
In the basal lamina (Blood testis barrier)
Sertoli cells have _ receptors and produce _.
Sertoli cells have FSH receptors and produce ABG.
Leydig cells have _ receptors and produce _ when stimulated.
Leydig cells have LH receptors and produce Testosterone when stimulated.
What is the function of capillaries in the seminiferous tubule?
Pick up testerone to ship around the body through circulatory system
What physiological processees must occur in the male for fertilization to occur?
Erection and Ejaculation
What is the pathway for the erectile reflex?
Stimuli: Tactile stimulus, Erotic stimuli, Thoughts about sex
Erection Mechanism
Flacid
What happens to the corpus cavernosa?
No blood to cavernous spaces
Erection Mechanism
Erect
What happens to the corpus cavernosa?
Vasodilation and increased blood flow into cavernous spaces
Erection mechanism
What is it?
The corpus cavernosa accommodates arterial blood
Vasodilation
Increased blood flow into cavernous spaces
Increased arterial blood flow compresses veins
Blood can’t leave via veins and is “trapped” in penis
What is the celluar mechanism for erection?
Sexual stmulation causes release od NO from cavernous nerves
NO activates Guanylyl cyclase (GC)
GC converts GTP to cGMP
cGMP causes relaxtion of arterial smooth muscle
Results in vasodilation and blood flow into the penis
How does Viagra work?
Viagra promotes erection
cGMP promotes vasodilation
cGMP is broken down to GMP by Type 5 phosphodiesterase
Viagra inhibits Type 5 phosphodiesterase from breaking cGMP to GMP to promote erection (↑cGMP)
Why do pregnant women frequently use the restroom?
Bladder sits underneath the uterus
As the fetus grows and uterus increases in size, the uterus and gravity compress the bladder
Identify the structurs in this image.
- Fallopian Tube
- Ovary
- Uterus
- Cervix
- Vagina
What is the function of the Fallopian Tube?
Transport egg
What is the function of the Ovary?
Produce eggs
What is the function of the Uterus?
Development of fetus
Normally pregnancy is maintained here
What is the function of the Cervix?
Junction between uterus and vagina
Barrier to protect uterus and fetus
What is the function of the Vagina?
Receptical for penis
Sperm deposited here
What are Follicles (F)?
They house developing oocytes (immature eggs)
What is the Corpus Luteum (CL)?
What does it do? How do they form?
Forms after ovulation and supports pregnancy?
What is the process of follicular development and ovaries?
- Embryonic development generats primordial follicles (Mitotic division, frozen in meosis)
- Primary follicles are present at birth (Frozen in primary stage until puberty)
- During puberty, primary follicles are recruited and mature to secondary, tertiary, and dominant follicles (usually only one makes it here)
- At ovulation, the oocyte breaks out the ovary and travels into the fallopian tubes
- The remaining ruptured follicle will be converted into the corpus luteum
What is the function of the Corpus luteum?
Produces a lot of cholesterol → converts into other steroid hormones
Regresses if not pregnant
What are the stages of the ovarian cycle?
Follicular phase - follicles are developing
Ovulation
Luteal phase - dominated by Corpus luteum
Preantral and antral (secondary, tertiary, and dominant) follicles contain _ and _ cells.
Preantral and antral (secondary, tertiary, and dominant) follicles contain granulosa and theca cells.
Theca cells
Where are they? What receptors do they have? What do they produce?
Outermost layer(s) of the follicle
LH receptors
Produce androgens
Granulosa Cells
Where are they? What receptors do they have? What do they produce?
Closest to the ovum
FSH receptors
Produce estrogens from androgens
What is the Basic Hypothalamic/Pituitary/Gonadal Axis?
Hypothalamus → secretes GnRH → stimulates Anterior Pituitary → secretes LH and FSH → stimulate Gonads (testes/ovaries) → secrete Testosterone, Estrogen, and Progesterone → stimulates Target Tissues
Androgen actions
What do androgens do?
Promotes a male like phenotype
Estrogen actions
Brain - change behavior
Heart and Liver - protect against cardiac diseases
Breast - Breast development and mammary gland milk production
Bone - Estrogen stops long bone growth development
Progesterone Actions
What does it do?
Primarily concerned with maintenance of a pregnancy
Mainly: Prepares edometrium for implantation; Helps maintain and noursih the growing baby
Menstruation and Pregnancy
Under the influence of LH and FSH, what gonadal cell types produces androgens and estrogens in males?
Sertoli - FSH - make sperm, ABP, inhibin
Leydig - LH - make testosterone
Under the influence of LH and FSH, what gonadal cell types produces androgens and estrogens in females?
Theca - LH - make androgens
Granulosa - FSH - make estrogens
What is the function of ABP?
Traps testosterone in the testis for sperm production
What is the function of inhibin?
Inhibits FSH but not LH
What are the phases of the uterine cycle?
Menses
Proliferative Phase
Secretory Phase
Menstrual Cycle
What is the process?
Anterior Pituitary releases FSH and LH → Follicles begin to develop (due to Anterior Pituitary Hormones → estrogen slightly increases, sharp increase in LH and FSH → Ovulation → Secretory phase caused by ovarian hormones (progesterone and estrogen)
How do the Ovarian Cycle, and Uterine cycle relate?
Ovarian, Uterine
Follicular Phase → Menses, Proliferative Phase
Ovulation → End of proliferative Phase; transition from proliferative to secretory and follicular to luteal
Luteal Phase → Secretory Phase
Uterine Phases
Menses
Define
Bleeding starts
Endometrial lining is shed
Uterine Cycle
Proliferative Phase
Cells begin proliferating to regrow endometrial lining
Uterine Cycle
Secretory Phase
Lining begins to secrete mucus
If pregnancy occurs creates a cervical plug to protect embryo
Secretes factors to promote pregnancy
Hormonal Control of the Menstrual Cycle
Early to mid follicular phase
Low levels of estrogen exert negative feedback to GnRH, FSH, and LH
Estrogen promotes more estrogen secretion by the follicle
AMH prevents follicles from forming
Positive feedback loop with ovary stimulates dominant follicle to secrete AMH and create negative feedback loop to reduce FSH/LH
Hormonal Control of the Menstrual Cycle
Late Follicular Phase and Ovulation
RIsing levels of estrogen plus increasing progesterone cause LH surge
Inhibin from grnulosa cells supresses FSH
Hormonal Control of the Menstrual Cycle
Early to mid-luteal phase
Combines estrogenand progesterone shut off FSH and LH
Hormonal Control of the Menstrual Cycle
Late Luteal Phase
Estrogen and progesterone fall when corpus luteum dies
Gonadotropins start follicular development for new cycle
What is the path of sperm through the female reproductive tract?
Vagina → Cervix → Uterus → Isthmus of fallopian tube →Ampulla of fallopian tubue
What is the path of an egg through the reproductive tract?
Ovary → Fallopian tube → fertilization → implant in uterus
Where does fertilization occur?
In the Ampulla of Fallopian Tube
What happens after fertilization?
Fertilizaed blastocyst moves to uterus and impants inendometrial lining
Sufficient _ is requuired to maintain pregnancy?
Progesterone
What is the timing/sequence of ovulation/fertilization/implantation?
- Ovulation
- Day 1: Fertilization
- Days 2-4: Cell division takes place
- Day 4-5: Blastocyst reaches uterus
- Days 5-9: Blastocyst implants
What issues do patients with PCOS have?
Insufficient progesterone making it difficult to conceive or maintain pregnancy
Causes increases in androgens and decreases in estrogens → LH fails to surge → fail to ovulate
High LH and low FSH
Define
Ectopic Pregnancy
Occurs when the blastocyst does not implant in the uterus
Most commonly: Fallopian tube
Can also implant: Cornual/Interstitial, Cervix, Abdomine
What is the function of Human Chorionic Gonadotropin (hCG)?
What does it do? Where does it come from?
Embryo prodcues hCG
hCG mimic LH → corpus luteum remains and continues to secrete progesterone
hCG levels rise early inpregnancy, then fall by week 20 when placenta tkes over progesterone production
maintains pregnancy
Used to detect pregnancy in pregnancy tests
Embryos produce _ until 6 weeks
Both male and female reproductive parts
Bipotential until 6 weeks
Embryo Development
If Female (XX)
What structures develop after week 6?
Gonadal cortex forms ovary
Gonadal medulla regresses
Wolffian duct regresses (due to lack of testosterone)
Mullerian duct becomes fallopian tube, uterus, cervix, and upper 1/3 of vagina (due to absenc of AMH)
Embryonic Development
If Male (XY)
What structures form after 6 weeks?
Gonadal Cortex regresses
Gonadal medulla forms testis
Wolffian duct forms epididymis, vas deferns, and seminal vesicle (testosterone present)
Mullerian duct regresses (AMH present)
What is the purpose of the Y chromosome in embryonic development?
The Y chromosome drives internal gonadal developmeny
SRY gene produces SRY protein which drives differentiation of testes
What is the function of sertoli cells in embryonic development in XY individuals?
Secrete AMH and cause regression of Mullerian Ducts
What is the function of leydig cells in embryonic development in XY individuals?
Secrete testosterone and DHT
Testosterone stimulates development of epididymis, Vas deferens, and seminal vesicles
DHT stimulates development of the penis and prostate gland
Embryonic developmment in XX individuals
What occurs in the absence of AMH and testosterone?
Mullerian ducts remain and form the fallopian tubes, uterus, and upper portion of the vagina
What occurs to an XX fetus if the mother has excess testosterone?
Fetus can develop male traits
Issues ith fallopian tube formation
What can occur in an XY individual with androgen insensitivity?
Receptors for androgens dont work
Lack of development of male traits due to lack of testosterone
Hormonal control of parturition (Birth)
What is the pathway?
Positive feedback of increases oxytocin secretion to uterine contractions until baby is born
Where is milk produced?
In the epithelial cells of the lobule
Each lobule contains _ and _ cells.
Epithelial
Myoepithelial
Each lobule has 15-20 lobules/breast
Fats, proteins, lactose, vitamins, and minerals are all secreted into the alveolar luminal spaces until…
Suckling stimulus is received
Hormonal control of lactation
Babys cry/suckling stimulate oxytocin → causes myopeithelial cells to contract → milk moves from the mammary lobules through the ducts and eventually out of the nipple
Suckling inhibits _ and promotes _.
Suckling inhibits dopamine release and promotes Prolactin release.
Prolactin promotes _ and inhibits _.
Prolactin promotes milk production and inhibits FSH and LH release.
