KSA 1

Urogenital system

contains the urinary system and the reproductive system

Reproductive system

genital system; gamete producing and transporting structures and external genitalia

urinary system

produces and excretes liquid waste

Sexual differentiation begins at

fertilization

Chromosomal and genetic sex is established by

the type of sex chromosome carried by the sperm

Gonads of two sexes until week 7

anatomically identical

Indifferent stage

until week 7 when the two sexes are anatomically identical

primoridal germ cells

contain the genetic material that determines the trajectory of the sexual differentiation of the structures

Develop in the lining of the yolk sac

primordial germ cells

Primordial germ cells migrate through

the dorsal mesentery until reaching the dorsal aspect of the abdominopelvic cavity

Default developmental pathway

the female

Primordial germ cells carrying the Y chromosome contain

the gene for testis-determining factor (TDF)

Urogenital ridge

induces he development of structures that will become the urinary and genital systems

All individuals contain

mesonephric duct and undifferentiated gonad

Mesonephric derivatives in males

rete testis, duct of epididymis, ductus deferens, ejaculatory duct and seminal gland, trigone of bladder

Mesonephric derivatives in females

trigone of bladder

Paramesonephric derivatives in males

none

Paramesonephric derivatives in females

uterine tube, uterus, upper 1/3 of vagina

The male phenotype develops

in the presence of testosterone

The female phenotype develops

in the absence of testosterone

Ductus deferens

what the mesonephric ducts develop into; transports sperm from testes to urethra

Male accessory organs develop as

epithelial outgrowths

Urethra develops the

prostate and bulbourethral glands

Ductus deferens develops the

seminal vesicles

Gabernaculum testis

strip of tissue that connects the testis to the inner surface of skin that will become the scrotum; remains as an embryological remnant

Testes migrate out of the

abdomen

Inguinal canal in males is created when

the testes pass through the abdominal wall

Ligament of ovary proper

embryological remnant in females of the gabernaculum

Round ligament

embryological remnant in females of the gabernaculum

Perineum

diamond-shaped region of the body between the upper thighs laterally, between the pubic symphysis anteriorly, and the coccyx posteriorly

In males, the urogenital sinus

closes

In females, the urogenital sinus

stays open

Vestibule

space where urogenital sinus stays open; space where urethra and vagina open into

Genital folds in the female become the

labia minora

Labioscrotal swellings in the female become the

labia majora

Genital tubercle in the female become the

head of the clitoris

Urogenital sinus

in males, formed when the genital folds fuse together

Male genital folds

close forming the urogenital sinus and the penile urethra

Line of fusion of the genital folds

penile raphe

Genital tubercle in the male become the

head of the penis

Labioscrotal swellings in the male become the

skin of the scrotum

Homologous

describes male and females structures that are derived from the same indifferent stage structure

Intersex

bodies that fall outt of strict male/female binary;

Differences of sex development

term to describe atypical processes of reproductive system development seen in intersex individuals; embryological processes result in gonadal, hormonal, and/or anatomical phenotype that is outside the male/female binary

Ambiguous genitalia

external genitalia that are not clearly male or female; arise from incomplete development or atypical combination of features

Examples of ambiguous genitalia

micro penis, enlarged clitoris on female, scrotalized labia

Mesonephros

induces the formation of the urinary system

Sex

assigned at birth; male, female, intersex

Gender Identity

what a person feels their gender is

Cisgender

when sex and gender identity are the same

Transgender

when sex and gender identity are not the same

Using sex/gender terminology when learning about and practicing medicine is important

to ensure clear and accurate communication, to appropriately care for all individuals, and to improve healthcare outcomes for all populations

Perineum

shallow, diamond-shaped chamber of the pelvis inferior to the pelvic diaphragm

Perineum is divided into

the anterior urogenital triangle and the posterior anal triangle

The center of the perineum is the

perineal body

Two compartments of the urogenital triangle

superficial perineal pouch and the deep perineal pouch

Superficial perineal pouch

lies between the perineal membrane and the perineal fascia; contains erectile bodies and associated muscles (superficial transverse perineal muscles in both males and females, and the greater vestibular glands only in females)

Superior perineal pouch in females contains

greater vestibular glands

Neurovasculature in the superior perineal pouch

inferior rectal and perineal artery and nerve

Perineal artery and nerve become

the posterior labial or scrotal artery and nerve

Deep perineal pouch

lies between the pelvic diaphragm and the perineal membrane; contains the urethra and external urethral sphincter

Deep perineal pouch in males

contains the deep transverse perineal muscles and bulbourethral glands in males

Deep perineal pouch in females

contains the compressor urethrae, urehtrovaginal sphincter, and smooth muscle

Internal pudendal artery

bifurcates (splits) to give off the deep artery of the penis or clitoris and the dorsal artery of the penis or clitoris

Ischioanal fossa

lies on each side of the anal canal

alcock canal

on the lateral side of the ischioanal fossa; contains the internal pudendal blood vessels and pudendal nerve

Three types of muscle tissue

skeletal, cardiac, smooth

types of muscle that are striated

skeletal and cardiac

Muscle

composed of cells/fibers specialized to contract; derived from mesoderm; three types

Sarcolemma

cell membrane of muscle cells

Sarcoplasm

cytoplasm of muscle cells

Sarcoplasmic reticulum

like smooth endoplasmic reticulum but in muscle cells

Fascicles

bundles of muscle fibers; many of these in muscle

Myofibrils

principal cytoplasmic component of the muscle fiber; unbranched structures that extend the full length of the muscle fiber; formed by myofilaments; organized in repeating segments in striated muscle; makes up 80% of the mass of the fiber

Myofilaments

make up myofibrils; specific proteins of the muscle cell or fiber; polymers of actin and myosin

Connective tissue

surrounds muscle

Epimysium

connective tissue that surrounds an entire muscle

Perimysium

connective tissue that surrounds a muscle fascicle

Endomysium

connective tissue that is the external lamina of a single muscle fiber/cell; comprised of reticular fibers

Skeletal muscle

muscle fibers are multi-nucleated syncytium located peripherally; striated appearance

Syncytium

multiple nuclei; characteristic of skeletal muscle

3 types of skeletal muscle fibers

slow twitch, fast twitch, intermediate fibers

Slow twitch/Type I/Red fibers

contain more myoglobin and mitochondria; use oxygen to produce energy (oxidative metabolism); involved in endurance activities; predominate in postural muscles; slow to fatigue

Fast twitch/Type II/White fibers

fast and forceful contractions; use glycogen for energy (anaerobic metabolism); quick fatigue - can only sustain contraction for short periods

Intermediate fibers

have features of type I and type II

Skeletal muscle development

mesoderm; myoblasts fuse to form myotubes; myofilament synthesis displaces nuclei to periphery; myoblasts exist as satellite stem cells that lie in external lamina

Myoblasts fuse to form

myotubes

Myotubes

long, multinucleated syncytial structures

What displaces nuclei to periphery in skeletal muscle?

myofilament synthesis

Myoblasts persist as

satellite cells

Satellite cells

adult stem cells that lie within the fibers external lamina; persisting myoblasts

External lamina

basement membrane associated with non-epithelia tissue; basal lamina

Sarcomere

functional unit of the myofibril; repeating units of these make up myofibrils; where muscle contraction takes place

Repeating units in myofibrils are

sarcomeres

Actin

thin filaments

Myosin

thick filaments

80% of the mass of the fiber is

myofibril

Nonmyofibrillar structures of the sarcoplasm

essential organelles required for metabolism (ex. mitochondria, glycogen)

Dark A band

entire length of mysoin, thick filaments with actin on periphery

Light I bands

just actin, thin filaments; bisected by Z band