Patho of Male Reproduction Flashcards
Define Testes
Generate male gametes and synthesize testosterone
Define Duct System
Receive, mature and transport male gametes
Define Accessory Gland
Secrete fluids that support sperm and generate the bulk of the semen
What are the accessory glands?
Prostate gland
Bulbourethral gland
Seminal vesicles
Where does spermatogenesis and spermiogenesis occur?
Seminiferous tubules of the testes
Define Spermiogenesis
Spermatids mature into spermatozoa with development of acrosome and flagella with loss of most cytoplasm
Define Spermatogensis
Process of forming haploid gametes
Mitosis, meiosis, spermiogenesis
Define spermatozoa
Fully differentiated and ready to be released
Have a head and tail
What does the head contain?
Acrosomal cap with proteolytic enzymes and hyaluronidase + the condensed nucleus
What does the tail contain & do?
Mostly mitochondria
Also known as Flagellum and enables movement
Semen is composed of?
Fluid and sperm from the vas deferens
Fluid from the seminal vesicles and prostate gland
Small amount of mucous secretions
How much sperm is produced per day from both testes
120 million
What is the average pH and average life span of sperm in female reproductive tract?
7.5
24-48 hours
Where does the bulk of semen made?
Seminal vesicles
How long can sperm be kept in the male reproductive tract?
They maintain viable for 1 month and metabolically inactivated
Testosterone is secreted by?
Leydig cells
What stimulates Leydig cells?
LH stimulates Leydig cells to produce testosterone
What is testosterone’s MOA?
Diffuses into cells
Converted to DHT by 5alpha-reductase
What happens after testosterone is converted to DHT?
It binds to the androgen receptor and that combination enters the nucleus and binds to the hormone response element of the DNA and induce gene transcription/protein synthesis
DHT is?
The active form and has a higher affinityf or the receptor than testosterone
Testosterone can also be converted to?
Estradiol via aromatase
Why would guys need estrogen?
The sertoli cell us it to help with spermatogenesis
What is the function of testosterone?
Secondary sex characteristics (body hair, baldness, lower of the voice, muscle development
It also increase bone growth and calcium retention, increased RBC and basal metabolism
Define Hypothalamic-Pituitary Testicular Axis
Hypothalamus secretes GnRH which stimulates teh AP to secrete LH and FSH
LH stimulates teh leydig cells to secrete testosterone which can feedback to the AP
FSH stimulates sertoli cells to initiate spermatogenesis and inhibin feeds back to AP
How does erection occur?
PS impulses generate in sacral spinal cord leading to erection
Hemodynamic changes
Arterial blood flow increases, fills sinusoids of corpora –> penile swelling and elongation
How is excretion prolonged?
Decreased venous outflow from the corpora, due to compression of blood outflow
I don’t get it, how does the outflow decrease?
The increase blood causes the veins to be pressed closed
Parasympathetic stage of erection?
Impulses call dilatation of the arteries of the penis allowing blood to flow into the erectile tissue
But how does it increase blood flow?
PS stimulation causes generation of NO which increases guanylate cyclase and increases the production of cGMP which decreases calcium and decrease SM contraction which causes vasodilation of the arteries and sinuses and increases the blood flow
Expansion of the cavernosum closes off the veins on the penis and trapping the blood inside
Sympathetic impulses from the spinal cord go to the genitals to cause emission how?
Contraction of the vas deferens, prostate gland and seminal vesicles which cause propulsion of the sperm and semen into the urethra
Sympathetic impulses from the spinal cord go to the genitals to cause ejaculation how?
Filing of the urethra with semen starts the stimulation of ejac
The rhythmic, wavelike increases in pressure in the genital ducts and urethra which causes propulsion of semen from the urethra to the exterior
Define Resolution
Male sexual excitement disappears and erection ceases
Causes of Erectile Dysfunction
Vascular problems (arteriosclerosis, hyperTN)
Peripheral neuropathies (DM)
Endocrine (hypogonadism, elevated prolactin)
Psych (depression and anxiety)
Drugs
Which drugs can induce erectile dysfunction?
Anti-cholinergic Dopamine antagonists Estrogens/anti-androgens CNS depressants Agents that decreases penile blood flow
What is the physiology of treatment of erectile dysfunction?
cGMP causes vasodilation of erectile tissue causing erection
cGMP can be degraded by PDE5
Certain drugs competitively and reversibly inhibit PDE5
Define Primary Hypogonadism
Decrease activity of testicles which leads to decrease in testosterone or other defect impaired male sexual function
Define Secondary Hypogonadism
Improper GnRH signaling which means lack of LH and androgens
Lack of FSH which means lack of sertoli cells
What is one other cause of hypogonadism?
Complete or incomplete androgen insensitivity (no receptors or lack of the enzyme)
What causes primary hypogonadism?
Defects of gonad function or response
Testosterone and sperm counts are below normal and LH and FSH are above normal
What causes secondary hypogonadism?
Hypothalamic or pituitary defects
Testosterone and sperm counts are below normal and LH and FSH are low or normal
Define Andropause
Late-onset Hypogonadism
Low testosterone with normal LH
Earlier onset with: obesity, DM, CVD, COPD, frailty
Testosterone Replacement Therapy
Rapid hepatic first pass metabolism
Common therapy: esters, alkylated androgens, transdermal patch or gel
Testosterone Esters
More lipophilic, given IM
Alkylated androgens
Slower hepatic metabolism (oral)
May cause hepatotoxicity
Transdermal Patch or Gel
Avoid first pass metabolism by transdermal delivery of lipophilic testosterone
What are adverse effects of testosterone?
Acne/oily skin, male pattern balding
Gynecomastia, reduced sperm production
More aggressive sexual behavior
Sodium retention!!! exacerbate HTN, CHF or edema
Predisposed to prostatic hyperplasia or cancer
Sleep apnea
Hepatotoxicity
Define gynecomastia
Abnormal development of large mammary glands in males
Due to obesity, genetic, hormones, disease or drug induced
What drugs can cause gynecomastia?
Anabolic steroids, alcohol and drugs of abuse Spironolactone Androgen receptor antagonists Chemo Psychiatric meds ACE_I
Benign Hyperplasia
Cellular proliferation which causes gland enlargement
Urinary urgency, frequency, straining and dribbling could be seen
Finasterid: Enzyme inhibitor
Prostate Cancer
Most common cause of death >75 yo
Treat with androgen receptor antagonists (Flutamide)
Long term AAS use cause?
LH and FSH secretion suppresion and testosterone production and spermatogenesis is inhibited
What are side effects of AAS
Suppression of HPT axis after stopping
Dysphoria could also be caused
