A&P II Exam 6 Reproductive System, Development, and Genetics

Amniocentesis

A medical procedure used to obtain amniotic fluid from the sac surrounding a developing fetus, allowing for genetic testing and assessment of fetal health.

Aneuploidy

A chromosomal condition involving an abnormal number of chromosomes, which can lead to genetic disorders.

Acrosin

An enzyme that helps during the process of fertilization by digesting the zona pellucida, allowing sperm to penetrate the egg.

Acrosome

The cap-like structure on the head of a sperm that contains enzymes necessary for fertilization, aiding in the penetration of the egg.

Autosomes

The chromosomes that are not directly involved in determining the sex of an individual, typically comprising 22 pairs in humans.

Blastocyst

A structure formed in the early development of mammals, consisting of an inner cell mass that will develop into the embryo and an outer layer that will form the placenta.

Blood-testis barrier

A physical barrier formed by Sertoli cells in the testes that helps protect developing sperm from the immune system and maintains an optimal environment for spermatogenesis.

Bulbourethral gland

A pair of glands located near the base of the penis, responsible for secreting a clear fluid that lubricates the urethra and neutralizes acidity before ejaculation.

Capacitation

The process by which sperm undergo physiological changes to gain the ability to fertilize an egg, typically occurring in the female reproductive tract. This process enhances sperm motility and prepares them for acrosome reaction.

Chorion

The outermost membrane surrounding an embryo in reptiles, birds, and mammals, playing a key role in gas exchange and formation of the placenta in mammals.

Codominance

A genetic scenario where both alleles in a heterozygote are fully expressed, resulting in offspring with a phenotype that is neither dominant nor recessive, such as AB blood type.

Corpora cavernosa

Two cylindrical structures in the penis that fill with blood during erections, contributing to penile rigidity.

Corpus albicans

The remnant of the ovarian follicle after ovulation, which forms from the corpus luteum and eventually degenerates if pregnancy does not occur.

Corpus luteum

A temporary endocrine structure in the ovary that forms after ovulation and secretes hormones such as progesterone, which supports early pregnancy.

Corpus spongiosum

The mass of erectile tissue surrounding the urethra in the penis that helps keep the urethra open during erection.

Crura

The elongated structures of the clitoris or penis that anchor them to the pelvic bones, playing a vital role in the support and erection process.

Depolarization

The process during which the membrane potential of a cell becomes more positive, typically due to the influx of sodium ions, leading to the initiation of an action potential.

Helps to prevent polyspermi.

Diploid

A cell or organism that has two complete sets of chromosomes, one from each parent, typically found in somatic cells.

Ectoderm

The outermost layer of cells in the early embryo, which develops into the skin, nervous system, and various other structures.

Endoderm

The innermost layer of cells in an embryo, which develops into the lining of the digestive and respiratory systems, as well as various glands.

Epididymis

A coiled tube located at the back of each testis where sperm matures and is stored.

Epistasis

When genes affect other genes

Ex. Coat color in Labrador Retrievers

Estrogen

is the principal female hormone (steroid hormone) that stimulates growth of sex organs and controls secondary sex characteristics

Fertilization

The process by which a sperm cell unites with an egg cell, resulting in the formation of a zygote.

FSH

A hormone produced by the pituitary gland that stimulates the growth of ovarian follicles in females and spermatogenesis in males.

Gametes

Reproductive cells that unite during fertilization to form a new organism, specifically sperm in males and eggs in females.

Genotype

The genetic constitution of an individual, representing the specific alleles inherited from both parents.

GnRH

A hormone released by the hypothalamus that stimulates the anterior pituitary to secrete FSH and LH, playing a crucial role in regulating the reproductive system.

Graafian follicle

A mature ovarian follicle that has reached the stage of ovulation, containing a secondary oocyte ready for release.

Granulosa cells

surround the developing oocytes and become the follicle

Haploid

A cell having a single set of unpaired chromosomes, typically seen in gametes.

Heterozygous

Having two different alleles for a specific gene, one inherited from each parent.

Homologous

Chromosomes that are similar in shape, size, and genetic content, one inherited from each parent.

Homozygous

Having two identical alleles for a specific gene, one inherited from each parent.

Incomplete dominance

A genetic situation in which one allele is not completely dominant over another, resulting in a phenotype that is a blend of the two alleles.

When the dominant allele does not completely mask the effects of the recessive allele in the heterozygote, it is called _________.

Karyotype

A complete set of chromosomes in an organism, typically arranged in pairs and organized by size and shape for analysis.

Luteinizing Hormone (LH)

A hormone produced by the anterior pituitary gland that triggers ovulation in females and stimulates testosterone production in males.

Locus

The specific location of a gene or genetic marker on a chromosome.

Mammary glands

specialized organs in mammals that produce milk to nourish infants.

• They are attached to the pectoralis major muscle by Cooper ligaments.

• They may contain large amounts of adipose tissue

• They are the organs of milk production

• They are modified sweat glands

Meiosis

A type of cell division that reduces the chromosome number by half (1/2), resulting in the production of four haploid gametes. Meiosis is essential for sexual reproduction and occurs in two sequential stages: meiosis I and meiosis II.

Mesoderm

The middle layer of an embryo in early development that differentiates into muscles, bones, and the circulatory system.

Nondisjunction

A genetic error that occurs when chromosomes fail to separate properly during meiosis or mitosis, leading to gametes with an abnormal number of chromosomes.

A mistake during segregation of chromosomes is called _________.

Oogenesis

The process of egg cell (ovum) development in females, which occurs in the ovaries. It involves meiosis and results in one viable egg and three polar bodies.

Ovulation

The release of a mature egg from the ovary, occurring around the midpoint of the menstrual cycle, triggered by hormonal changes.

Oxytocin

stimulates contractions during birth and ejection of milk

Parturition

The process of giving birth, where the fetus is expelled from the uterus through contractions.

Phenotype

The observable physical and physiological traits of an organism, determined by its genotype and environmental influences.

Pleiotropy

A single gene can affect many phenotypes

Pluripotent cells

can differentiate into all cell types of the body but cannot form extra-embryonic tissues like the placenta, whereas totipotent cells can.

Polyspermy

The fertilization of an ovum by multiple sperm cells, leading to abnormal development.

Prepuce

The fold of skin that covers the glans of the penis or clitoris, often referred to as the foreskin in males.

Primary follicle

An immature ovarian follicle that consists of an oocyte surrounded by a layer of granulosa cells, playing a critical role in female reproductive development.

Prolactin

stimulates milk production in the mammary glands

Prostate gland

A gland in the male reproductive system that produces a fluid that nourishes and transports sperm during ejaculation.

Recessive alleles

Alleles that only express their trait when two copies are present, often masking the effects of dominant alleles.

Secondary follicle

An ovarian follicle that has matured from a primary follicle, characterized by multiple layers of granulosa cells and the presence of an antrum, which contains follicular fluid.

Seminal vesicles

Glands in the male reproductive system that secrete a fluid rich in sugars, which provides energy for sperm and makes up a significant portion of semen.

Sertoli cells

Cells in the testes that support and nourish developing sperm cells, also known as sustentacular cells. They play a crucial role in spermatogenesis.

Spermatogenesis

The process of sperm cell development from spermatogonia through meiosis and maturation, occurring within the seminiferous tubules of the testes.

Stratum functionalis

The functional layer of the endometrium that thickens during the menstrual cycle and is shed during menstruation.

Testosterone

A steroid hormone produced primarily by the testes, responsible for the development of male secondary sexual characteristics and regulates sperm production.

Totipotent cells

_______ is a cell with the greatest developmental potential, capable of differentiating into all cell types in an organism, including both embryonic and extra-embryonic tissues. ____________ are present in the earliest stages of development, such as the zygote and early blastomeres.

Trisomy

A genetic disorder characterized by the presence of an extra chromosome in the cells, resulting in conditions like Down syndrome.

Tunica albuginea

The fibrous layer of connective tissue surrounding the testes and ovaries, providing structural support and protection.

Uterine tube

Also known as the fallopian tube, it is the structure through which eggs travel from the ovaries to the uterus and where fertilization typically occurs.

Vas deferens

The duct that transports sperm from the epididymis to the ejaculatory duct, playing a crucial role in male reproduction.

Yolk sac

A membranous structure that provides nutrients to the developing embryo in the early stages of gestation before the placenta is fully formed.

Functions of the reproductive system

The reproductive system's primary functions include the production of gametes, facilitation of fertilization, and support for embryonic development, ensuring species continuation.

Process of spermatogenesis – inc stages in order

The process of spermatogenesis involves several stages in order: spermatogonia differentiate into primary spermatocytes, which undergo meiosis to form secondary spermatocytes, followed by spermatids, and finally develop into mature spermatozoa. The stages include: spermatogonia, primary spermatocytes, secondary spermatocytes, spermatids, and mature spermatozoa.

The location of the testes and epididymides in the scrotum

provides a temperature that is suitable for normal sperm cell development

Contraction of the cremaster and dartos muscles

Pull the testes closer to the body

Seminiferous Tubules

where sperm cells are produced

tunica albuginea

The thick white capsule that covers each testes is called the ________.

Sustentacular Cells

provide nourishment for development of sperm cells

the order sperm cells would pass through as they move from the seminiferous tubules to the urethra

Rete testis

Efferent ductules

Epididymis

Ductus deferens (vas deferens)

Ejaculatory Duct

The secondary oocyte completes the second meiotic division when

it is penetrated by a sperm cell

When Fertilization occurs

nuclei of the secondary oocyte and the sperm cell unite

Endometrium

The layer of the uterine wall that is shed during menstruation is the _________

28: 14

The average menstrual cycle is about _________ days long; ovulation occurs on about day _________

The follicular phase of the ovarian cycle is characterized by

rapid development of ovarian follicles

Shortly after ovulation…

the granulosa cells become corpus luteum cells

Fusion of the male and female pronuclei

restores the diploid number of chromosomes

fast block to polyspermy

Depolarization of the oocyte plasma membrane occurs when the first sperm attaches to the integrin α6β1. This is called the _________.

Morula

Once the embryonic mass has 12 or more cells, it is called a _________.

The placenta plays an important role in

provision of nutrients to the fetus.

the fundus of the uterus

where implantation normally occurs

Amnion

The embryonic membrane that completely encloses the embryo in a watery sac is the _________.

Mesoderm

The germ layer where most muscle is derived from.

Ectoderm

The germ layer where the epidermis is derived from and the central nervous system components derived from.

Foramen Ovale

The opening that connects the right and left atria in the fetal heart is the _________.

When an embryo becomes a fetus

60 days after fertilization.

The major difference between an embryo and a fetus

organ systems are developing in an embryo while all organs are present in a fetus

Fossa Ovalis

The closed foramen ovale becomes the _________ after birth

Trophoblast

The single layer of cells that surrounds the blastocele is the _________.

The placenta and membranes surrounding the embryo develop from the _________.

(same answer)

The inner cell mass of the blastocyst…

contains cells that will form the embryo.

Germ layers

Gastrulation is the process of development that produces the _________.

Blastocyst

When the embryonic mass of cells develops an internal cavity, the mass of cells is called a/an _________.

At the time of implantation, the human embryo is in a stage of development known as the _________.

(same answer)

Findings of Mendel's work that are currently accepted as a valid explanation of genetic inheritance

• Genes exist in pairs in an individual.

• Gene pairs separate during gamete formation

• Gene pair segregation is relatively random during gamete formation.

A patient's karyotype indicates a chromosome number of 45. This result is best explained by…

nondisjunction in either the sperm cell or oocyte.

22 Chromosomes

The most likely outcome of nondisjunction is the production of a gamete receiving _________.