Reproduction 1 (male anatomy) Flashcards
What are the male gonads?
Testes
How many compartments do the testes have?
250-300
What is the role of the seminiferous tubules?
Sperm production
What is the role of the testes?
- Production of sperm (spermatogenesis)
- Delivery of sperm to female
They are the primary reproductive organ - the rest is secondary organs
What are the 2 main cells of the testes?
- Leydig cells (interstitual cells)
- Sertoli cells (epithelial cells)
What do the leydig cells do?
Secrete testosterone
They target the Sertoli cells
What do the sertoli cells do?
Support sperm development (sperm maturation)
Where are leydig & sertoli cells found?
Leydig cells are arranged in between the sertoli cells
The lumen is where the short sperm are release, this is why you get a sperm count in the millions
What is the blood testis barrier like?
- Has tight junctions
- Luminal compartment
- Basal compartment
Why is the blood-testis barrier important?
It is important as if the blood mixed w sperm then WBCs would kill the sperm
What is the role of the smooth muscle in the testis?
Peristalsis to propel sperm
What is the effect of testosterone before birth?
- Masculinses reproductive tracct & external genetalia
- Promotoes descent of testes into scrotum
What effect does testosterone have on sex-specific tissues after birth?
- Promotes growth & maturation of the reproductive system at puberty
- Is essential for spermatogenesis
- Maintains the reproductive tract throughout adulthood
How does testosterone effect other reproduction-related effects?
- Develops the sex drive at puberty
- Controls gonadotropin hormone secretion (testosterone)
What effects does testosterone have on secondary sexual characteristics?
- Induces male pattern of HAIR growth (e.g. beard)
- Causes the VOICE to deepen bc of thickening of the vocal folds
- Promotes MUSCLE growth responsible for the male body configuration
What effects does testosterone have on non-reproductive actions?
- Exerts a protein anabolic effect
- Promotes bone growht at puberty
- Closes the epiphyseal plates after being converted to estrogen by aromatose
- May induce aggression behaviour
What are 3 functions of sertoli cells?
(Part 1)
- Support sperm devleopment
- Secrete luminal fluid in which sperm devleop
- Secrete androgen-binding protein
What does androgen-binding protein do?
- Androgen buffer
- Helps maintain steady androgens in lumen
What are 3 functions of sertoli cells?
(Part 2)
- Target cells to testosterone & FSH (secrete chemicals that stimulate spermatogenesis)
- Secrete inhibin
- Secrete MIS (embryonic only)
What is inhibin?
Released from sertoli cells
Hormone of -ive feedback loop for FSH
Summary slide of sertoli cells function:
List the 7 functions of Sertoli cells:
- Secrete fluid into lumen of seminiferous tubules to support sperm development & transport
- Provide nutrient for developing sperm
- Secrete paracrines that stimulate spermatogenesis
- Secrete inhibin
- Secrete Mullerian inhibiting substance in fetal life
- Form blood-testis barrier
- Secrete androgen-binding protein into lumen of seminiferous tubules
What is the male copulatory organ?
Penis & scrotum
What is the role of the penis & scrotum?
Penetrates vagina & deposits sperm
At rest what is the penis like?
Flaccid
What happens to the penis during sexual arousal?
Penis undergoes erection
What are the 3 things that happens when a penis undergoes an erection?
- Blood flow to penis inc
- Engorges erectile tissue
- Penis swells & elongates
What happens during ejaculation?
Sperm ejaculates thru urethra
What are the characteristics of the scrotum?
- Suspended beneath penis
- Houses testes
- Sperm cannot develop at body temp
How does the scrotum help with sperm being unable to develop at body temp?
- Thin walled sac - 2-3 degrees cooler
- Dartos & cremaster muscles contract to regulate temp in cold
(this is why in the cold testes shrink)
Where is sperm stored?
In the epididymis
What is the order of the sperm from the seminiferous tubules to the Vas deferens (short version)?
Seminiferous tubules –> Rete Testis –> Efferent ductules (exits testes) –> Epididymus –> Vas deferens
What is the order of the movement of sperm form the seminiferous tubules to ejaculation (long version)?
- Starts in the testes in the SEMINIFEROUS TUBULE, exits this part
- Into the RETE TESTIS where it is pulled into these EFFERENT DUCTULES
- These connect to the EPIDIDYMUS where the sperm is stored until needed - when needed certain signals go here & transports the sperm to the VAS DEFERENS
- Then in the VAS DEFERENS different structures are added - this is where semen is made, SEMINAL VESICLES are added & it makes its way to the;
- EJACULATORY DUCT, from here it passes thru the PROSTATE GLAND as well where further chemicals are added
- It then reaches the URETHRA where the final thing is added; which is secreted from the BULBURETHRAL GLANDS
What is the order of the sperm from the Vas deferens to ejaculation (short version)?
Vas deferent –> (seminal vesicles added) –> Ejaculatory duct –> (prostate gland, chemicals are added) –> Urethra –> (Bulburethral glands)
() = acessory glands adding things
What are the acessory glands in the male reproductive system?
- Seminal vesicles
- Prostate gland
- Bulburethral glands
What is the role of the seminal vesicles?
Secrete alkaline (important to neutralise pH in women) fluid w fructose, enzymes & prostoglandins
What is the role of the prostate glands?
- Secrete citraze & enzymes
- Helps sperm get thru ovum to the egg cell
- Enzymes are used to break down the surface proteins on the surface of the egg cell so it can enter it
What is the role of the Bulburethral glands?
Secrete viscous fliud w mucus
What are prostoglandins important for?
To keep propelling the sperm to move
What are the 2 types of male gonadotropins (hormones) & where are they released from?
- FSH
- LH
The hypothalamus that communicates w the anterior pituitary gland
What is the role of FSH in men?
Stimulates gametogenesis
What is the role of LH in men?
Stimulates androgen secretion (e.g. testosterone)
Refer to the HPA axis on 2nd last slide
:)
Describe the HPA axis for the production of LH:
- Hypothalamus releases gonadotropin releasing hormone (GnRH)
- Targets the leydig cells - in response to LH the cells will secrete testosterone
- This mainly targets the sertoli cells
- Also released into the plasma –> has its own effects in tissues e.g. secondary sexual characteristics present themselves
- Also a feedback loop here - the anterior pituitary gland & the hypothalamus, is therefore responsible for stopping release of GnRH & LH
Describe the HPA axis for the production of FSH:
- Hypothalamus releases gonadotropin releasing hormone (GnRH)
- FSH targets sertoli cells found in the testes, this drives spermatogenesis
- Also drives secretion of another hormone inhibin –> part of -ive feedback to maintain stead amt of hormones in the blood to switch off the FSH signal
What are blood levels of sex hormones like in males?
Fairly constant on short term basis
Prepubescent:
- Low blood levels
Puberty & adulthood:
- High blood levels
What are the effects of androgens in males?
- Stimulate spermatogenesis
- Promote development of secondary sex characteristics during puberty & maintenance of these characteristics in adult life
- Inc sex drive
- Promote protein synthesis in skeletal muscle
- Stimulate growth hormone secretion, which permits bone growth during adolescence
- Promote development of male reproductive structures during embryonic life
