Unit B- Reproduction & Development

Secondary sex characteristics in males

Hair growth, muscle development, deeper voice.

Secondary sex characteristics in females

Menstrual cycle

Ureter

Transports urine from the kidney to the bladder.

Bladder

Collection location for urine.

Vas Deferens

Transports sperm from the testes to the urethra.

Seminal vesicle

Produces a fructose solution for semen. (Sugar energy)

Ejaculatory Duct

Gate keeper for semen. Closes when a male achieves an erection.

Scrotum

Pouch of skin that holds the testes outside of the body.

Testes

Produces speed and testosterone.

Prostate

Produces an alkaline (basic) solution for semen.

Cowper’s Gland

Creates a mucous fluid that cleans the urethra prior to ejaculation.

Urethra

Transports semen and urine to the external environment.

Epididymis

Responsible for sperm maturation.

Seminiferous Tubule

Directly responsible for producing sperm.

Sperm

Only contain 23 chromosomes, very little cytoplasm, streamlined for movement.

Ovaries

Site of follicular(egg) development secretes estrogen, which thickens the endometrium.

Fallopian tubes

Transports the egg from the ovary to the uterus, site of fertilization.

Uterus

Growth chamber for the developing fetus.

Endometrium

Uterine lining. Sheds once a month. Site of implantation of zygote if pregnant.

Cervix

Strong muscular opening to the uterus. Dilates during labor.

Follicle

Finite number of them are present at birth. Each one contains an immature egg and supporting cells.

Post-ovulation

After sufficient stimulation by FSH, a mature follicle releases an egg. The “leftover” structure turns into the corpus leteum, which secretes progesterone.

Sister Chromatids

The name given to each “component” of a chromosome.

Centromere

Structure that holds sister chromatids together. Which forms the chromosome.

Centriole

Present on each end of the cell; produce spindle fibers.

Spindle Fibers

Threads that attach to centromeres during cell division.

Haploid (n)

A cell that contains half the typical number of chromosomes (sex cells) (sperm or egg).

Diploid (2n)

A cell containing two copies of each chromosome (all cells except sex cells).

Homologous Chromosomes

Chromosomes that are similar in shape, size, and gene order. They contain the same genes but different alleles. Humans have 23 pairs.

Tetrad (4)

The structure that forms when pairs of homologous chromosomes pair up.

Synapsis

The process of pairing two homologous chromosomes.

Crossing over

The exchange of genetic material during synapsis. Promotes genetic variability.

Meiosis

A specialized type of cell division that reduces the chromosome number by half, producing four genetically unique gametes (sperm or egg cells) for sexual reproduction.

Early prophase I

Nuclear membrane dissolves; centrioles move to poles and spindle fingers grow; chromosomes condense and thicken. (Homologous chromosomes draw close together and form a tetrad).

Late prophase I

Homologous chromosomes undergo synapsis. (Crossing over takes place exchange of genetic material).

Metaphase I

Tetrads line up on the equatorial plate. (Spindle fibers attach).

Anaphase I

Homologous chromosomes separate and move to opposite poles during segregation. Double stranded chromosomes are now along each pole. (Segregation of each chromosome occurs independently).

Telophase I

Nuclear membranes form around the double stranded chromosomes. (Chromosomes organize/get ready)

Cytokenesis I

Daughter cells form (DO NOT ENTER INTERPHASE).

Prophase II

No crossing over

Metaphase II

Double stranded chromosomes line up in middle.

Anaphase II

Double stranded chromosomes split and move away from each other.

Telophase II

Nuclear membrane forms (ss).

Cytokinesis II

4 gametes, 23 chromosomes, ss.

Ploidy

In genetic, the Number of chromosomes occurring in the nucleus of a cell. In normal somatic, body cells, the chromosomes exist in pairs.

Mitosis

Performed by all autonomies. It is a form of cell division that produces daughter cells that are identical to parent cells.

Interphase

All chromosomes are duplicated, 46 pairs of chromatids.

Prophase

No crossing over, nuclear membrane begins to dissolve, chromatin condenses into chromosomes, centrioles move to opposite poles and attach/produce spindle fibers.

Metaphase

Chromosomes line up at the equatorial plate in the middle, spindle fibers attach to each centromere.

Anaphase

Spindle fibres contract, causing the chromosomes to split at each centromere, Sister chromatids move to opposite ends of the cell.

Telophase

Chromosomes de condense into two groups of chromatin, nuclear membrane, begins to form around each group, centrioles dissolve their spindle fibres.

Cytokenisi

Cleavage furrow “pinches” cell into two separate daughter cells, each daughter cell has a complete independent nucleus, each daughter cell now enters its own interface, and the cycle continues.

spermatogenesis

The biological process by which male germ cells develop into mature sperm cells. (Seminiferous tubules).

Oogenesis

The biological process by which female gametes (ova or egg cells) are produced and develop within the ovaries. Produces a large secondary oocyte and a tiny non-functional cell called a polar body.