Lecture 12 Study Guide Flashcards
Know the process of meiosis in the male and female, including the specifics of spermatogenesis and oogenesis. Make sure you understand how the numbers of chromosomes are replicated, then reduced during the process. Also, make sure you know what a spermatogonium cell and a oogonium cell is.
-Sex cell reproduction
-Cell division that results in cells (gametes) that possess half the chromosomes number of the parent cell (haploid).
-Produces four gametes
-Spermatogenesis in the male
-oogenesis in the female
23 pairs of chromosomes are duplicated to 46 chromosomes in parent cell in Interphase I of meiosis.
46 chromosomes are reduced to 23 chromosomes in mature sperm cells.
Meiosis in detail:
Interphase I-
-Replication of chromosomes in parent cell
-Results in 23 pairs of duplicated chromosomes
Meiosis I:
Reduction division
Prophase I-
Nuclear envelope and nucleoli disappear
-Mitotic spindle appears
-Chromosomes form homologous pairs called tetrads (synapsis)
Metaphase I-
-Chromosome pairs line up along the metaphase plate
Anaphase I-
-Chromosomes pairs separate
-one member of each pair moves to opposite poles
-Formation of cleaving furrow
Telephase I and cytokinesis-
-Completion of cleavage furrow
-Results in two daughter cells containing half the chromosomes number of the parent cell.
Meiosis II-
-Equatorial division
Prophase II
-Metaphase II
-Anaphase II
-Telophase II and cytokinesis
-Results in 4 gametes with 23 chromosomes each.
Spermatogenesis
(process of producing sperm cells):
-Sperm production from puberty throughout life
-sperm produced in the germinal epithelium of the seminiferous tubules
-sperm cells produced from spermatogonia cells containing 46 chromosomes.
-Meiosis reduces the number to 23 chromosomes in the mature sperm cell.
Spermiogenesis
(process of sperm cells maturing):
-last step of spermatogenesis
-immature spermatid becomes mature sperm
-Surrounded by nurse cells that:
-Maintains blood-testis barrier
-Supports cell division (FSH and testosterone)
-Support spermiogenesis
-Secretion of inhibition to keep our own body’s immune system from attacking sperm cells. (see notebook paper with spermatogenesis process)
Oogenesis:
-Begins with an oogonia (diploid number of chromosomes)
-oogonia gives rise to primary oocyte containing 46 chromosomes
-females are born with all potential eggs as primary oocytes
-Beginning with puberty, eahc month one primary oocyte undergoes meiosis I and gives rise to a secondary oocyte and a polar body. (see notebook paper with oogenesis process)
-Ovulation occurs
-If the secondary oocyte is penetrated by a sperm cell, meiosis II occurs
-If meiosis II is completed, a second polar body is formed.
-Nuclei of the sperm and ovum then fuse.
spermatogonium cell(spermatocytes)-sperm cells; first cell in spermatogenesis.
oogonium cell-egg cells(oocytes)in first step in oogenesis.
Know the primary sex organ in both the male and female, as well as the excitatory organ in both the male and female.
Testes: primary sex organs in males
Penis: excitatory organ in males
Ovaries: primary sex organs in females
Clitoris: excitatory organ in females
Know which hormones stimulate the following:
a. spermatogenesis (production of sperm)-FSH & Luteinizing hormone (LH)
b. testosterone production
c. oogenesis (maturation of the ovarian follicle)-FSH
d. ovulation-LH
What is the corpus luteum formed from? What hormone does it produce?
The corpus luteum is formed from the remaining cells from the ovarian follicle once it has matured, ruptured, and released oocytes. The corpus luteum secretes progesterone.
Know the structure and function of a mature sperm cell.
Head-
-Contains 23 chromosomes
-Covered by an acrosome that contains enzymes to aid in oocytes penetration
Body-
-Contains mitochondria for ATP production
Tail-
-Flagellum
-provides locomotion for sperm cell.
Know the functions of the reproductive system.
-Produce gametes(sex cells)
-Transport gametes
-Maintain gametes
-Maintain developing fetus in the female
-Produce sex hormones
Know the function of the following components of the male reproductive system:
a. seminiferous tubules-produce sperm cells.
b. epididymis-site of sperm storage
c. prostate gland-secretes alkaline fluid to enhance sperm mobility fluid in semen during ejaculation
d. seminal vesicle-secretes nutrient rich alkaline fluid for energy for sperm.
e. bulbourethral gland-secretes lubricant for penis.
What are the male and female secondary sex characteristics?
Male secondary sex characteristics:
-Increased Body hair growth
-Lower pitched voice
-Increase in muscular growth
-Increase in bone strength
Female secondary sex characteristics:
Know the functions of, and the structures which produce, the following hormones (in both males and females, when appropriate):
a. Follicle Stimulating Hormone-anterior pituitary gland secretes FSH to stimulate spermatogenesis in the seminiferous tubes.
In the female, FSH causes the maturation of one premordial follicle and maturation of the primary oocyte.
b. Luteinizing Hormone-anterior pituitary gland secretes LH to stimulate interstitial cells to produce male sex hormones (testosterone)
In female LH cause ovulation of secondary oocyte resulting in a corpus luteum(follicle transformed into corpus luteum).
c. Estrogen-produced by the maturing ovarian follicle in the female. Estrogen helps maintain female sex characteristics.
d. Progesterone-produced by the corpus luteum(former ovarian follicle) in the female to help the lining of the uterus to prepare itself for a fertilized egg(ovum).
e. Testosterone—major male sex hormone
-Develops male sex hormones
-development and maintenance of male secondary sex characteristics.
Know the structures in the spermatic cord.
1)Vas deferens
2)Testicular artery
3)Autonomic nerves-help the reproductive system function.
4)Testicular veins
5)Lymphatic vessels
6)Cremaster muscle-extension of the abdominal internal oblique muscle that encases the testes and functions to elevate the scrotum during sexual arousal and cold exposure.
What muscle makes up the scrotum and what muscle is it an extension of?
Cremaster muscle-extension of the abdominal internal oblique muscle that encases the testes and functions to elevate the scrotum during sexual arousal and cold exposure.
Know the following structures and their primary functions in the female reproductive system.
a. uterus—muscular organ that receives embryo and maintains life during development.
3 layers of uterus:
-Endometrium-inner lining.
(Endometriosis is the inflammation of the inner lining of the uterus.)
-Myometrium-middle layer(uterine muscle;smooth muscle)
-Perimetrium-outer visceral covering
-
b. fallopian (uterine) tubes—
-Also called uterine tubes or oviduct
-pass from ovaries to uterus
-Fimbriae-finger like structures that sweep back and forth to draw an ovum into the fallopian tube) at the end of each fallopian tube.
-Inner lining covered with cilia
-Site of fertilization
Know the female reproductive cycle and the hormones involved in the reproductive cycle.
1)Menstrual cycle is initiated by follicle stimulating hormone which stimulates follicle maturation
2) Maturing follicle secretes estrogen
a. maintain secondary sex
characteristics
b. causes thickening of uterine wall
c. Ovulation triggered by LH
3)If the oocyte is not fertilized by a sperm, the corpus luteum will degenerate and the levels of progesterone will begin to fall causing a degeneration of the uterine lining and menustration.
-During the cycle, estrogen and progesterone inhibit the release of LH and FSH.
Ovulation occurs once in a reproductive cycle. Ovulation occurs every 28 days. We ovulate midway through the reproductive cycle (about 14 days before our period).
