Anatomy II

Chapters 22-24

Meiosis

Divide diploid cells into haploid cells (2n>n)

Homologous

Similar but not identical pairs

Gubernaculum

A muscle attached to the bottom of each testis

Cryptorchidism

Failure of one or most testis to descent into the scrotum

Sertoli (nurse) cells

Line the walls of the seminiferous tubules

Tunica Dartos

Muscle of scrotum

Cremaster Muscle

Muscle in spermatic cord

Pampiniform Plexus

Blood cooling mechanism

Epididymis

Storage and maturation site for spermatozoa

Vas Deferens

Muscular organ connecting epididymis to the ejaculatory duct

Seminal Vesicle

Sac-like pouch that secretes alkaline fluid that prepares reproductive tract and increases ejaculate volume

Prostate Gland

Ring structure surrounding the urethra

Bulbourethral (Cowper’s) Gland

Secretes mucus fluid

Scrotum

Pouch of skin that houses the testes

Penis

Composed of three columns of erectile tissue

Corpora Cavemosa

Pair

Corpus Spongiosum

Inferior to cavermosa

Sensory Glands

Enlarges to form the glans penis

Erection

During sexual stimulation, nitric oxide causes vasodilation of arteries leading to the penis

Ejaculation

Sympathetic input causes peristaltic contraction within the epididymis, vas deferens, and ejaculatory ducts

Hypothalamus

GnRH stimulates the pituitary

Testosterone Production

Accounts for male secondary sexual characteristics

Pituitary

LH, FSH< act at the level of the tests

Ovaries

The ovaries are the main functional unit of female reproduction

Oogenesis

During prenatal development several million oogonium will form in the cortex

LH

Causes Luteinization

Corpus Luteum

Yellow body

Luteinization

The process from going to a follicle to corpus lutetium

Corpus Albicans

White body

FSH

Stimulates growth of oocytes by increasing proliferation of Granulosa cells

Antrum

Fluid-filled cavity in follicle

Ovulation

As estrogen levels increase the walls of the ovary begin to weaken and thin (eventually, the secondary oocyte and the first polar body will be released from the ovary)

Oviducts

Tubes used to transport oocytes to uterus

Infinium

Has a funnel-shaped end near the ovary

Uterus

Hollow muscular organ shaped like an inverted pear

Endometrium

Inner layer

Myometrium

Thick muscular layer

Perimetrium

Surrounds the uterus (covering)

Vagina

Extends from cervical region of the uterus to the outside of the body

Morula

Once the 16th cell stage is reached

Blastocyst

Fluid begins to fill the cavity and it becomes this

Inner Cell Mass

will form the fetus

Trophoblasts

Will form the placenta and supporting structures

Implantation

Begins around day seven

Identical Twins

One sperm, cells split

Fraternal Twins

Two sperms, two eggs

Ectoderm

Forms the nervous system

Mesoderm

Forms muscles bone and blood

Endoderm

Digestive, respiratory, and urinary tract

Human Chorionic Gonadotropin

Hormone that spikes in the first two months of pregnancy (used to determine in urine if pregnant through pregnancy tests)

Chorionic Villi

Projections into the endometrium

Umbilical Cord

The amnion extends to the placenta forming this cord

Fetal Stage

Once this species of an embryo can be determine visually it is termed a fetus (around week 8)

Genetics

Study of DNA

Gene

A segment of DNA that encodes a certain amino acids

Proteins

A long line of amino acids

Genome

All genes required for a particular species

Genotype

The type of gene an individual possesses

Alleles

Alternative types of genes

Phenotype

Physical visible expression of a gene

Autosomes

1-22 pairs of chromosomes

Sex Chromosomes

23rd pair of chromosomes

Homologous Pair

Similar but not identical pair of chromosomes

Homozygous Dominant

EE

Heterozygous

Ee

Homozygous Recessive

ee

Genotypic ratio

The ration of the three possible combinations (EE, Ee, ee)

Phenotypic Ratio

The ratio of visible differences

Codominance

Both genes are expressed (AB blood)

Incomplete Dominance

Neither gene is expressed over the other (meet in the middle)

Polygenic Inheritance

More than one gene is needed to express a trait (skin and eye color)

Sex-linked Inheritance

Trait is linked to sex chromosome