Ch 16 - Reproductive System Flashcards
What similarities are there between the male and female reproductive systems?
They both produce gametes, the cells that combine to form a new individual of the species (eggs and sperm). The testes and ovaries produce sex hormones.
When does sexual maturity occur in boys and girls?
Girls = 10-14 Boys = 12-16
What is mitosis?
When cells duplicate and divide to create an exact replica of itself. Like a copy machine.
What is meiosis?
A type of cell division that occurs in the testes (during the production of sperm) and in the ovaries (during the production of eggs). There are two functions of meiosis:
- Reduction division = chromosomes are reduced from 46 (diploid, or 2n number) to 23 (haploid, or n number)
- requires meiosis I and meiosis II, and forms gametes - Meiosis introduces genetic variation, ensuring that we don’t make an exact copy of either parent
What is a zygote?
The first cell of a new human being
Where are the testes located?
In the scrotum
Where is sperm produced, and where does it mature?
Produced in the testes and matures in the epididymis, a tightly coiled duct lying just outside of the testes. Maturation is required for the sperm to swim to the egg
What is the flow of semen through the male reproductive system?
- Sperm produced in testes
- Sperm matures in epididymis outside of testes
- Sperm passes through vas deferens (large tube that passes through abdominal cavity)
- The seminal vesicle, prostate gland and bulbourethral glands add secretions to the seminal fluid
- Semen passes through ejaculatory ducts
- Ejaculatory duct enters the urethra
- Semen ejects into vagina
What are the male reproductive organs, and what do they do?
- testes = produce sperm and sex hormones
- epididymis = ducts where sperm matures and some sperm is stored
- vasa deferentia = conduct and store sperm
- seminal vesicles = contribute nutrients and fluid to semen
- prostate gland = contributes fluid to semen
- urethra = conducts sperm
- bulbourethral glands = contribute mucus-containing fluid to semen
- penis = organ of sexual intercourse
What’s the pH of seminal fluid?
7.5 (slightly basic)
What is the glans penis, and what covers it?
The large tip of penis covered by foreskin that is oftentimes removed in circumcision
How does the penis become erect?
Fills with blood due to a high-energy compound called cGMP (similar to ATP) causing smooth muscle to relax and the erectile tissue to fill with blood
What is erectile dysfunction (ED)?
impotency = inability to achieve or maintain an erection suitable for sexual intercourse. Medications for its treatment inhibit the enzyme responsible for breaking down cGMP, ensuring that a full erection will take place.
Vision problems because the same enzyme is in the retina
What is the refractory period?
A period of time where stimulation doesn’t bring about an erection. Increases with age. This occurs in men, not women.
How much sperm is ejaculated in sexual intercourse?
There are over 400 million sperm in the 3.5 mL of semen expelled
When do testes drop into the scrotal sacs?
The last two months of fetal development
What is is the process of spermatogenesis?
The production of sperm.
- Mitosis occurs, where spermatogonia divide into two duplicate cells
- Meiosis I: The 2 diploid cells transform into 2 haploids (cells w/ 23 chromosomes)
- Meiosis II: The 2 haploid cells copy themselves (now there are 4 total haploids)
- Sperm begins to take shape (late spermatid)
- Spermatids develop into sperm
This whole process takes 74 days.
Which cell type supports, nourishes and regulates the process of spermatogenesis? What other role to these cells play?
Sertoli cells (purple in book).
They also produce a hormone called “inhibin” to block GnRH and FSH when appropriate
Hypothalamus produces GnRH…
…which stimulates the anterior pituitary to produce FSH & LH
What role do FSH and LH play (anterior pituitary) in the male reproductive system?
FSH - promotes production of sperm in seminiferous tubes
LH - controls production of testosterone in interstitial cells between seminiferous tubes
What is a mature sperm called, and what parts does it contain?
Spermatozoa. 3 parts:
- head = acrosome stores enzymes needed to penetrate egg
- middle piece
- tail
How long does sperm live in female genital tract?
no more than 48 hrs
What are interstitial cells & why important?
Cells that lie between the seminiferous tubules that secrete the male sex hormones, androgens
What happens if testosterone in blood is high?
Causes hypothalamus and ant. pituitary to decrease secretion of GnRH and LH, respectively.
What are two other names for the uterine tubes?
Oviducts or fallopian tubes. Extend from ovaries to the uterus
What do the ovaries produce?
Eggs (ova) and female sex hormones, estrogen and progesterone
Because uterine tubes aren’t attached to the ovaries, what “connects” them?
Fimbriae, or fingerlike projections of the uterine tubes that sweep over the ovaries. Cilia helps move an egg (ovum) to the uterine tube as well.
What are the female reproductive organs, and what is their role?
- ovaries = produce eggs & sex hormones
- uterine tubes (oviducts) = conduct eggs; location of fertilization
- uterus = houses developing fetus
- cervix = contains opening to uterus
- vagina = receives penis; birth canal; menstrual flow exit
- fimbriae/cilia = helps move egg from ovaries to uterine tube
How long does an egg live if fertilization doesn’t occur?
6-24 hrs