BIO 241 Ch 27 - terminology

gamete for men

sperm

zygote

formed when sperm fertilizes an egg

germ cells

specialized cells in the testes that become sperm

rete testes

network that extends out from the seminiferous tubules 

efferent ductules

12; carry sperm to epididymis; the sperm move due to cilia

ejaculatory duct

passes through prostate into urethra

semenogelin

provides gel-like matrix; the stickiness allows sperm to stay contained inside semen

serine protease

breaks down semenogelin 20-30 min later

sertoli cell/nurse cell

provide nutrition, secrete androgen-binding protein, secrete inhibin, blood testis barrier; need this and leydig cells to produce sperm

what do sertoli cells act like

a revolving door because one part of the cell opens up and gives space for developing sperm to move into

interstitial cell/leydig cell

where testosterone is produced; need these and sertoli cells to produce sperm

acrosomal vesicle

helps the sperm break through the zona pellucida of the egg

scrotum

skin surrounding testis

testes

organ that produces sperm

seminiferous tubules

where spermatogenesis occurs

epididymis

where the sperm can mature and is stored for 20 days

ductus deferens

muscular tube that passes through the spermatic cord and widens which turns into an ampulla

ampulla

when ductus deferens widens

seminal vesicles

posterior to bladder; secretes fluid that supplies 70% of semen

prostate gland

surrounds urethra and ejaculatory ducts inferior to bladder; secretes alkaline; makes up 25-30% of semen

bulburethral glands

inner end of penis; produces pre-ejaculate fluid; protects sperm from acidity of female; has lower viscosity allows sperm to move easily

root

attaches to pelvic floor;

shaft

composed of erectile tissue (corpus spongiosum and corpus cavernosum); surrounded by tunica albuginea; separated by median septum

glans

distal end with external urethral orifice; deposit semen and urine

corpus cavernosum

2; has a large blood supply and makes penis rigis when erected

corpus spongiosum

1; surrounds urethra and prevents compression. of urethra when penis is erected

prostatic urethra

allows passage of semen to exit the body

membranous urethra

provides voluntary control over urination

penile/spongy urethra

carries urine from bladder outside body; carries semen during ejaculation

what is the primary sex organ

testes

describe secondary sex characteristics

facial and chest hair, deep voice, increased muscle mass

where are leydig cells located

interstitial space of the testes

what is contained in the spermatic cord

ductus deferens, lymph vessels, testicular nerves, testicular artery, veins, (pampiniform plexus)

what muscles are involved in temperature regulation

cremaster muscle, dartos muscle, pampiniform plexus

what does cremaster muscle do when it is cold

contracts when cold, moving testis closer to body to preserve heat

what does cremaster muscle do when it is warm

relaxes when warm, moving testis further away from body to prevent overheating

dartos muscle

gives scrotum a more textured look

what does the dartos muscle do when cold

contracts when cold which reduces surface area to preserve heat

what does the dartos muscle do when hot

relaxes when hot which increases surface area to promote cooling

pampiniform plexus

cools the warm arteriole blood by acting as a countercurrent heat exchanger; 1.5-2.5 degC lower than core temp

why are nurse cells so important for the production of sperm?

provide nutrients and structural support for germ cell development

What is produced by seminal vesicles

fructose, prostaglandins, semenogelins

What is produced by prostate gland

alkaline, Zn rich milky fluid

what is produced by bulbourethral gland

pre-ejaculate fluid

what sperm count is considered to be characteristic of infertility?

< 20-25 million sperm/mL

what are the 3 principles of spermatogenesis 

division/remodeling of germ cells into four mobile cells with flagella, reduce chromosome number by ½, gene shuffling which creates a new gene combo in each sperm

why are the three principles of spermatogenesis important?

they produce genetically diverse, mature, and functional sperm cells

explain spermatogenesis moving from spermatogonia to spermatozoa

type a spermatogonia → type b spermatogonia via mitosis → primary spermatocyte → secondary spermatocyte via meiosis I → spermatid via meiosis II → spermatozoa via spermatogenesis

when or where does sperm become: anatomically mature

seminiferous tubules

when or where does sperm become:
functionally mature

epididymis

when or where does sperm become:
activated (able to swim)

ejaculation

what cells are 2n vs 1n? What does this mean?

2n is diploid, two complete sets of chromosomes, 2n=46; 1n is haploid, one complete sets of chromosomes, n=23

decipher between spermatogenesis and spermiogenesis

spermatogenesis is the overall process and spermiogenesis is the the final stage of spermatogenesis where spermaids become spermatozoa

what do sperm use to break through the zona pellucida surrounding the ovum?

acrosome

describe the hormonal control of male reproduction

hypothalamus secretes GnRH which makes the anterior pituitary secrete follicle stimulating hormone and luteinizing hormone

what hormone kicks off this process at
puberty?

gonadotropin releasing hormone

are FSH and LH produced at the same time?

yes, they are released from the anterior pituitary gland triggered by GnRH

what hormone is absolutely necessary for sperm production?

testosterone 

what does FSH do

stimulates Sertoli cells to secrete androgen-binding protein

what does LH

stimulates interstitial endocrine cells (leydig cells) to secrete androgens