1 reproductive system
function of reproductive system
- reproduce offspring
- the chief function of the reproduction system is to ensure survival of the species
- it produces the gametes ( sex cells) under the direction of hormones
it is an organ that produce the gametes
1. testes (male) - produce sperm
2. ovaries (female) - produce ovum
Gonads
Male reproductive
- an externalbsac (pouch) of skin fascia and muscle ( cremaster and dartos) surrounding the testes
- the testes found on the _____
scrotum
•Accessory Sex Organs - ____________ for transport and nourishment of the gametes;
glands and ducts
– pulls/ elevates testes closer to the body in cooler temperatures; in a warmer environment this muscle relaxes, and the testes are held further from the body
cremaster muscle
- are the male gonads.
•They are located behind the penis and inside the scrotum.
•Consists of many highly coiled seminiferous tubules surrounded by layers of connective tissue.
Testes
The testes are surrounded by the _______________, which is dense connective tissue, and they are enclosed in a serous sac – the __________. The tunica albuginea separates the testis into 250-300 lobules.
- TUNICA ALBUGINEA
- TUNICA VAGINALIS
Within each lobule are tubules: _______-. Their function is to produce sperm.
SEMINIFEROUS TUBULES
____________, scattered between seminiferous tubules produce androgens (ex. testosterone).
•Leydig cells (interstitial cells)
•Some of the Effects of testosterone in the body
muscle and bone growth
facial and pubic hair growth
thickening of vocal cords
growth of pharyngeal cartilage
hair follicle effects
stimulates sebaceous glands
- process of forming sperm
–Begins at puberty – 400 million sperm per day
–Cells differentiate and move toward the lumen
•Spermatogenesis
the step on process of forming sperm
•Stage 1 – formation of spermatocytes
•Stage 2 – meiosis
•Stage 3 – spermiogenesis
–Spermatids differentiate into spermatozoa
The external male sex organ used to copulate and ejaculate semen and to convey urine outside the body.
PENIS
THREE REGIONS OF THE PENIS
1.ROOT of the penis is in the perineum
2.SHAFT – the body of the penis
3.GLANS is the enlarged tip of the penis.
the _________ contains a nucleus with 23 densely packed chromosomes; the _____________ at the tip of the head contains enzymes that breakdown the mucus of the female reproductive tract, and breakdown the barrier around the egg;
-head
-acrosomal cap
the ______ contains mitochondria which provide the ATP to move the tail;
midpiece
the ____ of the sperm is a flagellum, which with a whip-like motion mobilizes (moves) the sperm
tail
newly formed sperm detach from the wall of the seminiferous tubule and enter the lumen; these sperm are still __________-(cannot swim)
immotile
is controlled by the hormones follicle-stimulating hormone (FSH) and luteinizing hormone (LH) from the anterior pituitary gland, and testosterone from the interstitial (Leydig) cells
spermatogenesis
spermatogenesis is controlled by the hormones ____________ and __________- from the anterior pituitary gland, and testosterone from the interstitial (Leydig) cells
- follicle-stimulating hormone (FSH)
- luteinizing hormone (LH)
Surrounding the glans is the _______- (foreskin), a continuation of the skin of the penis that extends over the glans.
PREPUCE
- surgical removal of the prepuce or foreskin; somewhat controversial as to its benefits
•circumcision
In cross-section, within the penis there are three tubes (2 posterior) called______________. The posterior two are the CORPUS CAVERNOSUM (Corpora cavernosa, plural). The anterior one is the CORPUS SPONGIOSUM, within which is the urethra.
CYLINDERS OF ERECTILE TISSUE.
In cross-section, within the penis there are three tubes (2 posterior) called CYLINDERS OF ERECTILE TISSUE. The posterior two are the _______________. The anterior one is the ___________, within which is the urethra.
CORPUS CAVERNOSUM (Corpora cavernosa, plural)
CORPUS SPONGIOSUM
The erectile tissue is lined by dense fibrous connective tissue which extends into itself, creating vascular spaces which can fill with blood, causing the penis to become more rigid and expanding. The erection is due to _______-, with blood moving into erectile bodies (tissue).
vasodilation
•Duct System
1. epididymis
2.ductus deferens (vas deferens)
3.Ejaculatory duct
4.urethra
Comma-shaped, tightly coiled tube
Found on the superior part of the testis and along the posterior lateral side
Functions to mature and store sperm cells (at least 20 days)
Expels sperm with the contraction of muscles in the epididymis walls to the vas deferens
1. epididymis
Carries sperm from the epididymis to the ejaculatory duct
Passes through the inguinal canal and over the bladder
Moves sperm by peristalsis
Ends in the ejaculatory duct which unites with the urethra
Vasectomy – cutting of the vas deferens at the level of the testes to prevent transportation of sperm
2.ductus deferens (vas deferens)
– cutting of the vas deferens at the level of the testes to prevent transportation of sperm
Vasectomy
- formed by the joining of the ductus deferens and seminal vesicle duct; transports sperm through the prostate gland; joins with the urethra
.Ejaculatory duct
Extends from the base of the urinary bladder to the tip of the penis
Carries both urine and sperm
urethra
sperm flow through the duct system:
testis → epididymis → ductus deferens → ejaculatory duct → urethra
•Accessory Glands
a.seminal vesicles
b.prostate gland
c.bulbourethral glands
Located at the base of the bladder
Produces a thick, yellowish secretion (60% of semen)
- the fluid that contains fructose, vitamin C, and other nutrients to nourish sperm, along with other substances to aid sperm viability;
a.seminal vesicles
Encircles the upper part of the urethra
Secretes a milky fluid (30% of semen)
It helps neutralize the acidity of other fluids after ejaculation
Helps to activate sperm
Enters the urethra through several small ducts
b.prostate gland
- pea-sized glands; produce a thick, alkaline mucus that lubricates the urethra for safe passage of sperm
c.bulbourethral glands
Mixture of sperm and accessory gland secretions (60% from seminal vesicles, 30% from prostate glands, about 10% from the vas deferens and small amounts from the mucous glands, especially the bulbourethral glands.)
SEMEN
Functions of the SEMEN
1.Medium for sperm to swim in
2.Nutrients for sperm (fructose)
3.Neutralizes acidity in vagina to allow sperm to survive
The usual quantity of semen ejaculated at each coitus averages about ___, and each ml of semen is an average of about 120 million sperm (it can vary from 35 to 200 milion). This means an average total of 400 million sperm are usually present in each ejaculate. When the number of sperm in each ml falls below about 20 million, the person is likely to be infertile.
3.5 ml
The usual quantity of semen ejaculated at each coitus averages about 3.5 ml, and each ml of semen is an average of about 120 million sperm (it can vary from 35 to 200 milion). This means an average total of 400 million sperm are usually present in each ejaculate. When the number of sperm in each ml falls below about 20 million, the person is likely to be ________.
infertile.
Male Reproductive Hormones
this hormone is released from the hypothalamus and causes the anterior pituitary to release LH and FSH
is secreted in pulses at 60-90 minute intervals; this pulse frequency stays relatively constant
this results in plasma levels of FSH, LH, and testosterone staying within a relatively narrow range
GnRH - gonadotropin-releasing hormone
what is GnRH stand for?
- gonadotropin-releasing hormone
GnRH hormone is released from the ___________ and causes the anterior pituitary to release LH and FSH
hypothalamus
____________is secreted from the anterior pituitary gland; this hormone causes testosterone secretion by the interstitial cells (Leydig Cells) of the testes
leuteinizing hormone (LH)
______________is secreted by the anterior pituitary gland
this hormone targets sustentacular cells (Sertoli Cells) in the seminiferous tubules for sperm production or spermatogenesis
as spermatogenesis accelerates, inhibin secretion by sustenacular cells increases; the inhibin (by way of negative feedback) inhibits FSH production in the anterior pituitary
follicle-stimulating hormone (FSH)
- secreted by the interstitial cells (Leydig Cells) of the testes;
supports spermatogenesis
affects the central nervous system, libido, and related behaviors
it stimulates metabolism throughout the body, especially pathways concerned with protein synthesis and muscle growth
it establishes and maintains the secondary sex characteristics, such as facial hair, body hair, increased muscle mass, larynx growth, and body size
blood ________- levels remain constant until the age of thirty, and then begin to diminish, reducing by about 80% by 80 years of age
testosterone
Scrotum an external sac (pouch) of skin, fascia and muscles ___________- surrounding the testes
Cremaster and Dartos
•testes Consists of many highly coiled ____________--surrounded by layers of connective tissue.
seminiferous tubules