Embryogenesis of the Pituitary Gland and Reproductive Organs

ANSC 318

embryo

an animal in the early stages of development that has not taken an anatomical form that is recognizable as a member of a species

embryogenesis

the formation and growth of an embryo; this is the phase of prenatal development

describe embryogenesis of the pituitary and the male and female repro tracts

a coordinated series of events involving the merging of several types of tissue that will ultimately form complete reproductive glands and organs

the normal development of what system is amongst the most complex of all organ systems and required critical timing for successful development?

urogenital system

what does faulty embryogenesis often result in?

reproductive failure of either the male or the female

what is the name of the living organism formed after the joining of egg and sperm?

zygote

the zygote mitotically divides over and over again for many days to become a ________

morula

the newly divided cells that make up the morula are ___________

totipotent

totipotent

any particular cell within the morula can be destined to become any variety of the common organs we know of

the morula further develops into a _________, this contains an Inner Cell Mass (ICM)

Blastocyst

the blastocyst undergoes a process called _________, which sets all cells of the inner cell mass on their determined course for development (they’re no longer totipotent but now pluripotent)

gastrulation

the ICM gives rise to the embryo through the organization of _______ ______

germ layers (endoderm, mesoderm, ectoderm)

the three individual germ layers are destined to be formed into ______ categories of organs which make up the body

unique

differentiation

the process whereby a group of unspecialized cells develop into recognizable groups of cells that have a common function

what are the germ layers that appear prior to embryo attachment to the uterus?

• endoderm

• mesoderm

• ectoderm

endoderm

• the innermost cellular layer of the embryo will give rise to the digestive tract, liver, pancreas, lungs and endocrine organs

mesoderm

• will give rise to the circulatory, skeletal, muscular and urinary systems

• most of the repro system is derived from this

• develops between the ectoderm and endoderm

ectoderm

• will give rise to the central nervous system, sensory organs, mammary glands, sweat glands, skin, hair, claws and hooves

what are the 2 separately functioning lobes of the hypophysis (pituitary gland)

• anterior lobe

• posterior lobe

the anterior lobe (adenohypophysis) originates from…

the ectodermal tissue in the roof of the embryos mouth

define the prefix “adeno-”

refers to tissues that are glandular in structure

the posterior lobe (neurohypophysis) originates from…

the floor of the ectodermal tissue of the embryo’s brain

the cells of the adenohypophysis are differentiating into cells capable of producing a variety of _________, while the cells of the neurohypophysis are differentiating into _______

hormones; nerve cells (neurons)

what does the posterior lobe contain?

the axons and nerve terminals of neurons whose cell bodies are located in the hypothalamus above

in the embryo, the repro tract develops in close proximity and at the same time as the ______ _______

renal system

the sex chromosomes within the spermatozoa determines…

whether the embryo will become male or female

(true/false) X and Y chromosomes have a gene called Sex Determining Region (SRY) Gene

False, only on the Y chromosome

the substance that controls the pathway toward either male or female development is ___________ and it is controlled by the SRY gene on the Y chromosome

SRY Protein

when a SRY gene is presented by a sperm cell, SRY protein is synthesized by the…

primitive gonad

(this stimulates the development of the male repro system)

when a SRY gene is NOT presented by a sperm cell, a _______ gene is presented

female

(leads to production of female repro tract)

the development of female and male gonads is an _______ process in both sexes

active

the development of the ovary required an active pathway but under _______ gene control

female

ovarian development is NOT done by default in the absence of an _______ protein

SRY

male repro tract

descent of the testicles into the scrotum

the testes are formed at the level of the ______

ribs

testes descend into the scrotum late in ________

gestation

during the development of the male repro tract, how do the testicles descend into the scrotum?

a ligamentous attachment called the gubernaculum shrinks and the testicles are pulled down through the inguinal ring and into the scrotum

what are the 2 layers of peritoneum that cover the testicle?

visceral vaginal tunic and parietal vaginal tunic

explain how the visceral and parietal vaginal tunics being “slippery” affect the function of the testes

it allows them to move freely within the scrotum during physical activity and during contraction of the external cremaster and the tunica dartos