Genetics #2

Fertilized egg that develops into a new individual

Unfertilized germ cells

Male gamete

Female gamete

Organs where gametes are produced

Male gonads that produce spermatozoa and male sex
hormones

Female gonads that produce oocytes and female sex hormones

The process of sperm production

Small, tightly coiled tubes inside the testes where sperm are produced

Diploid cells that undergo meiosis to form haploid spermatids

Where sperm are matured and stored

A duct connected to the epididymis, which sperm travel through

A short connector from vas deferens to urethra

Tube that passes from bladder to the outside
Functions in urine transport and, in males, also carries sperm

Glands that secrete fructose (energy source) and
prostaglandins (chemical messengers) into the semen

Locally acting chemical messengers that stimulate contraction of the female reproductive system to assist in sperm movement

Secretes a milky, alkaline fluid that neutralizes acidic vaginal secretions and maintains sperm

Glands that secrete a mucus-like substance that
provides lubrication for intercourse

A mixture of sperm and various glandular secretions containing 5% spermatozoa

In the ovary, a developing egg is surrounded by an outer layer of follicle cells

Release of a secondary oocyte from the follicle
Usually occurs monthly during a female’s reproductive lifetime

The process of oocyte production

Cells that produce primary oocytes by mitotic division

The largest cell produced in the body. It is large enough to be seen with the naked eye

• Also called the fallopian or uterine tube
• A duct with fingerlike projections partially surrounding the ovary, connecting to the uterus
• Guides oocytes from the ovary to the uterus • Location of fertilization

Hollow, pear-shaped muscular organ where a
fertilized egg will develop

Inner lining of the uterus that is shed at menstruation if fertilization has not occurred

Lower neck of the uterus opening into the vagina

Opening that receives the penis during intercourse and also serves as the birth canal

• Spermatogenesis begins during puberty
• Millions of sperm are always in production
• Spermatogenesis takes about 48 days
• Meiotic division produces 4 sperm

• Primary oocytes produced during embryonic
development remain in meiosis I until ovulation
• Ovulation begins during puberty
• Meiotic division produces 1 oocyte and 2-3 polar bodies

Fusion of two gametes to produce a zygote

The developmental stage at which the embryo
implants into the uterine wall

A cluster of cells in the blastocyst that gives rise to the embryonic body

The embryo implants in the uterine wall, and
membranes develop to support the embryo

Outer layer of cells in the blastocyst that gives rise to the membranes surrounding the embryo

• Two-layered structure formed from trophoblast
• Releases human chorionic gonadotropin (hCG) hormone which maintains uterine lining and stimulates endometrial cells to produce hormones
• Grows and forms villi that exchange nutrients and wastes with maternal blood circulation, eventually forming the placenta

• First month: basic tissue layers form; most of the body
is divided into paired segments
• Second month: most major organ systems are formed
• Third month: embryo becomes a fetus; sexual development is initiated

• Increase in size and organ-system development • Bony parts of skeleton form • Heartbeat is heard with a stethoscope • Fetal movements begin

• Rapid growth • Circulatory and respiratory systems mature
• Birth is a hormonally induced process at the end of the 3rd trimester

• Any physical or chemical agent that brings about an
increase in congenital malformations • Radiation, viruses, medications, alcohol

A constellation of birth defects caused by maternal alcohol consumption during pregnancy

the most common teratogenic problem and leading cause of preventable birth defects

Sex of an individual is defined at three levels

• Sex-determining region of the Y chromosome
• Located near the end of the short arm of the Y chromosome
• Plays a major role in causing the undifferentiated gonad to develop into a testis

• Hormone produced by developing testis that causes breakdown of Müllerian (female) ducts in the embryo

An X-linked genetic trait that causes XY individuals to develop into phenotypic females

• An autosomal genetic condition that causes XY
individuals to develop the phenotype of females
• Caused by mutations in several different genes
• Affected individuals have both male and female structures, but at different times of life
• At puberty, females change into males

• Dosage compensation in mammalian females
• Random inactivation of one X chromosome in females equalizes the activity of X-linked genes in males and females

• A densely staining mass in the somatic nuclei of
mammalian females • An inactivated X chromosome, tightly coiled

Traits controlled by autosomal genes that are usually dominant in one sex but recessive in the other sex

A phenomenon in which expression of a gene depends on whether it is inherited from the mother or the father