Reproductive System Flashcards
Gonads
ovaries and testes
Gonads produce?
gametes (sex cells)
Sexual maturation, formation of sex cells and pregnancy are controlled by?
hormones secreted by the pituitary gland and gonads
Primary Functions of Male Reproductive System:
- Production of male sex hormones
- formation of sperm (male gamete)
- placement of sperm in the female reproductive tract where one sperm can unite with a secondary oocyte (female gamete)
Organs of male reproductive System:
- paired testes
- accessory ducts
- external genitalia
Testes
Male gonads or sex glands
What divides testes into lobules?
septa and each lobule contains several seminiferous tubules
What lines the seminiferous tubules?
spermatogenetic epithelium and supporting cells
Function of spermatogenic cells
divide to produce sperm
Supporting teste cells:
support and nourish spermatogenic cells
regulate sperm production
Interstitial cells
fills spaces between seminiferous tubules
produce testosterone male sex hormone
Spermatogenesis
process that produces sperm by the division of spermatogenic cells
True or false: Spermatogenesis begins at puberty and continues for a lifetime
true
Spermatogenesis is controlled by:
- follicle stimulating hormone (FSH)
- luteinizing hormone (LH)
- testosterone
Spermatogonium (STEP 1)
Large cell near basement membrane of spermatogenic epithelium.
Contain 46 chromosomes (2 chromatids per chromosome)
Divides by mitosis to form 2 daughter cells with 46 chromosomes each.
Formed in the walls of the seminiferous tubules
Type A spermatogonium
remains a spermatogonium; will divide repeatedly by mitosis.
Formed in the walls of the seminiferous tubules
Type B spermatogonium
is pushed inward and becomes a primary spermatocyte.
46 chromosomes (2 chromatids per chromosome)
Formed in the walls of the seminiferous tubules
Primary Spermatocyte (STEP II)
contains 46 chromosomes (2 chromatids per chromosomes)
undergo meiosis (2 cell divisions) that reduce number of chromosomes in the daughter cell in half
Formed in the walls of the seminiferous tubules
Steps of Spermatogenesis (CHROMOSOME EVENTS)
Prior to meiosis I, chromosomes replicate
Each is composed of two chromatids joined at a centromere.
What happens during metaphase of meiosis I?
chromosomes align as homologous pairs.
What happens during cytokinesis of meiosis I?
members of each pair separate into deferent secondary spermatocytes
Each secondary spermatocyte receives only 23 replicated chromosomes.
Spermatid
Contains 23 chromosomes
4 are formed
loses their cytoplasm and forms a flagellum
forms sperm containing 23 chromosomes.
What happens in meiosis II?
chromatids separate into different daughter cells.
Genetic diversity of sperm
- Random alignment of paire homologous chromosomes, during meiosis I (daughter cells contain different combination of maternal and paternal chromosomes
- Crossover during Meiosis 1:Exchange of DNA between paired homologous chromosomes during meiosis I.
true or false: some chromosomes contain genes from both parents.
true
Head of Sperm
contain 23 chromosomes
Acrosome
covers the nucleus, contains enzymes that help the sperm penetrate a secondary oocyte
Neck of sperm
connects the head to the flagellum
flagellum of sperm
enables movement
middle piece, principal piece and end piece
True or false: Middle piece of flagellum contains the mitochondria?
true
Accessory Ducts (male reproductive tract)
- epididymis
- ductus deferens (vas deferens)
3.ejaculatory duct - urethra
Epidimys
Comma shaped, along the top and back of the testis.
Receives sperm from seminiferous tubules.
Site of sperm maturation and storage.
Mature as they slowly move 10 -14 days. Stored here until they are ejaculated.
True or false: Sperm mature in around 10 to 14 days
true
true or false: sperm stored for mor than 2 months are destroyed and absorbed
true
Ductus deferens
Extends from epididymis upward, merges with duct from the seminal vesicle.
uses peristalsis to move sperm
Ejaculatory Duct
enters the prostate and merges with urethra
During ejaculation, contracts to mix seminal vesicle secretions with sperm and push them into urethra.
Urethra
Extends from the urinary bladder through the penis to the external environment.
Roles of the urethra
- transport urine
- carries semen during ejaculation
true or false: urethra can transport urine and carry semen at the same time
false
Accessory glands (exocrine glands)
- Seminal Vesicles
- Prostate Gland
- Bulbo- Urethral gland
Seminal Vesicles
paired glands on the back of the urinary bladder
Duct merges with the ductus deferens to form ejaculatory duct.
True or false: seminal vesicle secretion is alkaline
true; to help regulate pH of semen
contains fructose and prostaglandins
What percent do secretions of seminal vesicle make of semen?
60%
Prostate
Pear-shaped gland encircling the urethra where it exits urinary bladder.
Ejaculatory duct passes through rear half of prostate to join with urethra.
true or false: prostate secrete alkaline/milky fluid into urethra
true; keep sperm pH slightly alkaline (milky)
has chemicals that activate swimming movements of sperm
What percent do secretions of prostate make of semen?
30%
Bulbo urethral glands
Two small, spherical glands below the prostate gland near the base penis.
true or false: prostate secrete alkaline/mucus like fluid into urethra in response to sexual simulation
true; neutralizes acidity of urethra and lubricates the end of the penis
Semen
Fluid that passes from urethra during ejaculation.
All three glands contribute secretions, in addition to sperm and fluid from testes.
50- 150 million sperm/ml.
Composition of Semen:
slightly alkaline pH 7.5
neutralize acidity in male’s urethra and female’s vagina (protects sperm)
Contains fructose from seminal vesicles.
Swimming movements are activated by prostatic fluid.
Prostaglandins from seminal vesicles:
reverse peristalsis in the uterus and uterine tubes, which accelerates the movement of sperm in the female reproductive tract stimulated by
prostaglandins from seminal vesicles
Swimming movements are activated by
prostatic fluid
during what month of fetal development do testes migrate to scrotum
7th
Male External Genitalia
scrotum and penis
Scrotum
Sac of skin and subcutaneous tissue that holds testes
who controls the descent of the testes?
testosterone
Function of scrotum muscles
Both are used to elevate and depress the testes.
Adjust temperature of the testes.
Elevated closer to the body in cold temperatures and depressed in warm temperatures.
Muscles of Scrotum
- Dartos Muscle (smooth)
- Cremaster (two thin ribbonlike skeletal)
Penis
composed of spongy erectile tissue; Enables penis to become enlarged and rigid during sexual stimulation.
how many columns of erectile tissue compose the body of the penis.
3
Corpora cavernosa
two columns located on the top of an erect penis.
Prepuce
loose sheet of skin that covers the glans
Corpus spongiosum
located on the bottom of an erect penis. Expands at the tip to form the glans penis
glans penis
contains numerous sensory receptors and the external urethral orifice
In absence of sexual stimulation
Vascular sinusoids in erectile tissue contain small amount of blood; Penis is flaccid
True or false: Sexual stimulation initiates
parasympathetic action potentials
true; Cause dilation of arterioles and constriction of venules supplying the erectile tissue ; Erectile tissues become engorged with blood→ produces the erection
true or false : Sexual stimulation stimulate secretion from bulbo-urethral glands.
true
true or false Sympathetic action potentials stimulate peristaltic contractions of most accessory ducts and glands.
true; force semen into urethra
After ejaculation __________ cause constriction of the arterioles and dilation of the venues, allowing the accumulated blood to leave the penis
Sympathetic action potentials
true or false: Another orgasm is not possible for a period of time after ejaculation occurs.
true
Testosterone secretion at puberty
Promotes maturation of male reproductive organs
Stimulates continuation of spermatogenesis
Promotes development of male secondary sex characteristics
Testosterone secretion fetal development
produced by adrenal glands, promote formation of male sex organs
androgens
male sex hormones
true or false: is testosterone Most important androgen in males
true; produced by the testes
secondary sex characteristics at puberty
Growth of body hair (axillary, face, and pubic regions)
Increased muscular development.
Development of heavy bones, broad shoulders, and narrow pelvis.
Deepening of the voice due to the enlargement of the larynx and thickening if the vocal folds.
Increase in rate of cellular metabolism.
Increase rate of red blood cell production.
at what age does testosterone production start to decline
40 years, decline in the function or reproductive organs and secondary sex characteristics.
Sexual development begins at and lasts until
11 -12 and lasts until 15- 17
at puberty the hypothalamus secrete ____________ hormone.
gonadotropin releasing hormone (GnRH
GnRH stimulates the anterior lobe of the pituitary gland to release two hormones
- Luteinizing hormone(LH)
- Follicle-stimulating hormone (FSH)
Luteinizing hormone (LH)
- Promotes growth of interstitial cells of the testes
- Stimulates production of testosterone by interstitial cells
Follicle-stimulating hormone (FSH)
Acts on supporting cells and works with testosterone in the seminiferous tubules to stimulate spermatogenesis.
true or false: Male Sex Hormone Secretion Controlled by negative-feedback mechanism.
true
what happens when testosterone levels increase?
GnRH production is inhibited. Loss of GnRH, decrease LH and FSH production.
What happens with decrease in LH
decreases testosterone secretion by the interstitial cells.
what happens with decrease in FSH
decreases sperm production.
What happens when testosterone level decrease?
GnRH is secreted; causes LH and FSH to be secreted. LH increases testosterone production. FSH increases sperm production.
When is inhibit secreted and by who?
secreted by supporting cells. Secretion increases when sperm count is high.
What does inhibit do?
Decreases FSH secretion, which decreases sperm production.
Inhibit secretion decreases when ______
sperm count is low. FSH secretion increases, which increase
sperm production.
