ANIMAL REPRODUCTION and DEVELOPMENT Flashcards
Non-animal: Asexual reproduction
Offspring are clones; sexual reproduction’s advantage is VARIATION.
Fission:
Separation of organism into two new cells(amoeba)
Budding:
New individual splits off from existing one (hydra)
Fragmentation + Regeneration:
Single parent breaks into parts that regenerate into new individuals (sponge, planaria, starfish)
Parthenogenesis:
Development of egg w/out fertilization; resulting adult is haploid (honeybees, some lizards)
HUMAN REPRODUCTIVE ANATOMY
Gonads-
Male-
Female-
Gonads- Reproductive structure responsible for production of gametes.
Male = testis
Female = Ovaries
-Secondary sex characteristics: Indication of sexual maturity but not specifically involved in reproduction (e.g. breasts)
HUMAN REPRODUCTIVE ANATOMY 1. Female reproduction System: A.Ovary B. Oviduct C. Uterus *Endometrium D. Vagina *Cervix
A)Ovary - OVA, or eggs, are produced. Each female has two ovaries.
B)Oviduct- Eggs move from ovary to uterus through oviduct(fallopian/uterine tube). There are two oviducts, one for each ovary.
C) Uterus - A fertilized ovum implants(attaches) on the inside wall, or the ENDOMETRIUM, of the uterus. Development of the embryo occurs here until birth.
D)Vagina = at birth, the fetus passes through the CERVIX(an opening in the uterus), through the vagina, and out of the body.
HUMAN REPRODUCTIVE ANATOMY
- Male Reproductive System
- Testis
- seminiferous tubules, interstitial cells, scrotum
- Epididymis
- Vas Deferens
- Testis
Testis = Each of the two testes consists of SEMINIFEROUS TUBULES for the production of sperm and INTERSTITIAL CELLS which produce male sex hormones(testosterone and other androgens). The two testes are contained in a single sac, the SCROTUM, which hangs outside the body.
EPIDIDYMIS = This coiled tube, one attached to each testis, is the site for final maturation and storage of the sperm.
VAS DEFERENS = Transfer sperms from one epididymis to urethra.
HUMAN REPRODUCTIVE ANATOMY
- Male Reproductive System
* Seminal vesicles
* Prostate gland
* Bulbourethral glands(aka Cowper’s glands)- Penis
- semen
- Penis
- Seminal vesicles = Two glands, during ejaculation secrete into vas deferens: they make up most of the content for semen.
* Prostate gland = Secretes milky alkaline fluid into urethra. Makes up 30% of semen fluid.- Bulbourethral glands(aka Cowper’s glands) = helps neutralize any urinary acids in the urethra. Protects the sperm.
- Penis = The urethra passes through the penis and serves to transport SEMEN, the fluid containing sperm and secretions, into the vagina. It also serves in the transport of urine out of the body.
- Bulbourethral glands(aka Cowper’s glands) = helps neutralize any urinary acids in the urethra. Protects the sperm.
HUMAN REPRODUCTIVE ANATOMY
- Male Reproductive System - Sperm
Sperm - what is it?
PArts of the sperm -
Sperm = compact packages of DNA specialized for the effective delivery of the male genome. They consists of the following structures:
SPERM HEAD - The head of the sperm contains the haploid nucleus with 23 chromosomes(in humans. At the tip of the sperm head is the ACROSOME(a lysosome containing enzymes which are used to penetrate the egg). The ACROSOME originates from Golgi body vesicles that fuse to form a single lysosome.
HUMAN REPRODUCTIVE ANATOMY
- Male Reproductive System -
SEVEnUP:
Seminiferous tubules —> epidydmis —-> Vas Deferens —> Ejaculatory Duct —-> Urethra —-> Penis
GAMETOGENEIS IN HUMANS:
Gametogenesis:
Gametogenesis: Consists of the meiotic cell divisions that produce eggs in females (oogenesis) and sperm in males (spermatogenesis)
-Egg contains most of the cytoplasm, RNA, organelles, and nutrients made by developing embryo.
GAMETOGENEIS IN HUMANS:
Oogenesis:
* Oogonia * Primary oocytes * Follicle * Secondary Oocyte * Polar body
Oogenesis: being during embryonic development; OOGONIA(fetal cells) —->(mitosis) PRIMARY OOCYTES —-> (meiosis begins) and remain at Prophase I until puberty, at which time one primary oocyte during menstrual cycle (averaging 28 days) continues its development through the remainder of meiosis I within the FOLLICLE(which protects and nourishes oocyte) —> (completion of Meiosis I) SECONDARY OOCYTE(most of cytoplasm) +POLAR BODY(small cytoplasm; may or may not divide but products disintegrate) formed; now arrested at metaphase of meiosis II until—-> ovulation.
GAMETOGENEIS IN HUMANS:
-Ovulation:
Ovulation: releases SECONDARY OOCYTE from the follicle. If fertilized by sperm —> it moves through the oviduct, the secondary oocyte will begin meiosis II and produce an egg that combines with the chromosomes contributed by the sperm. The secondary daughter cell of meiosis II, again a POLAR BODY(degenerate)
GAMETOGENEIS IN HUMANS:
- SPERMATOGENESIS:
* Spermatogonia
* Primary Spermatocytes
* Secondary Spermatocytes (how many?)- Spermatids (how many?)
Spermatogenesis = Begins at puberty within seminiferous tubules of testes. SPERMATOGONIA cells —-> (mitosis) PRIMARY SPERMATOCYTES —>(meiosis) 2 SECONDARY SPERMATOCYTES —-> (Meiosis II) 4 SPERMATIDS.
GAMETOGENEIS IN HUMANS:
- Sertoli Cells
- spermatozoa(sperm)
-Sertoli Cells: Happens in the seminiferous tubules which provide nourishment to spermatids as they differentiate into mature SPERMATOZOA (sperm. They complete maturation(gain motility and are stored) in the epididymis.
Capacitation:
Penultimate(last but one in a series of things) step in maturation of the spermatozoa while in the vagina, allows for egg penetration.
HORMONAL CONTROL OF HUMAN REPRODUCTION
1. Female Reproductive Cycle
What 2 cycles do they consist of?
- OVARIAN CYCLE(ovary)
2. MENSTRUAL CYCLE (uterus)
HORMONAL CONTROL OF HUMAN REPRODUCTION
1. Female Reproductive Cycle
-Menstrual Cycle: What is it divided into?
What is the process like?
-HYPOTHALAMUS AND ANTERIOR PITUITARY INITIATE
-FOLLICLE DEVELOPS
-DEVELOPMENT OF ENDOMETRIUM
It is divided into follicular, ovulation, luteal, menstruation(proliferative/secretory/menstruation)
HYPOTHALAMUS AND ANTERIOR PITUITARY INITIATE: monitor estrogen and progesterone in blood;
Low level —> hypothalamus —–> GnRH —->FSH and LH(via anterior pituitary- NEGATIVE FEEDBACK——>
FOLLICLE DEVELOPS ——> FSH stimulate follicle to secrete estrogen—-> lots of estrogen(positive feedback on AP)—–> LH SURGE —-> OVULATION(follicle is now CORPUS LUTEUM-maintained by LH[which along w/ estrogen begins to decrease after ovulation], secretes —–> estrogen + progesterone ——-> DEVELOPMENT OF ENDOMETRIUM(thickens in prep for implantation of fertilized egg)
HORMONAL CONTROL OF HUMAN REPRODUCTION 1. Female Reproductive Cycle -Menstrual Cycle: IF IMPLANTATION OCCURS -----> *Corpus Luteum
IF IMPLANTATION OCCURS —–> embryo (placenta) secretes chorionic gonadotropin(HCG) —> mainting CORPUS LUTEUM—-> PRODUCTION of E+P remain high —–> endometrium stays —–> HCG is later replaced by progesterone from placenta.
HORMONAL CONTROL OF HUMAN REPRODUCTION
The Menstrual Cycle: Consists of the thickening of the endometrium of the uterus in preparation for implantation of a fertilized egg and the shedding of the endometrium if plantation does not occur.
OVARIAN CYCLE
1. Follicular Phase: 2. Ovulation: 3. Luteal Phase: * Estrogen * Progesterone * Corpus Luteum
OVARIAN CYCLE
1. Follicular Phase = development of egg and secretion of estrogen from follicle. 2. Ovulation: Midcycle release of egg. 3. Luteal Phase = Secretion of ESTROGEN and PROGESTERONE from CORPUS LUTEUM after ovulation.
Estrogen- thicken endometrium
Progesterone - development and maintenance of endometrial wall.
HORMONAL CONTROL OF HUMAN REPRODUCTION
- Male Reproductive Cycle:
- The hormonal process
* Sertoli
GnRH —> FSH + LH(also called ICSH, interstitial cell stimulating hormone —–> testosterone and androgens from testis_
- FSH and testosterone —–> influence SERTOLI cells to promote development of sperms (nourish sperm during development - spermatogenesis). Hormone and gamete production are constant unlike female.