The presence of the Y chromosome
Does not guarantee the development of male secondary sex organs
Only germ cells undergo meiosis
which produces four haploid cells with 23 chromosomes each
The ovarian cycle
Typically lasts 28 days, with day 14 considered to be the first day after ovulation
stimulates the interstitial cells of the testes to secrete testosterone
The formation order of ejaculation
seminiferous tubule, rete testis, epididymis, ductus deferens, ejaculatory duct, and urethra
In Meiosis, each parent cell in the male reproductive system produces
four haploid cells
The term menstrual cycle specifically refers to
the cyclic changes in the uterus determined by shifting hormonal changes
Most ovulation home test kits measure
LH surge, which happens about 24 hours before ovulation
During the follicular phase , granulosa cells secrete
estradiol which stimulates secretion of LH
suppresses spermatogenesis without affecting testosterone secretion
After puberty the vaginal lining becomes
stratifed squamous epithelium, to resist abrasion
Why is breast milk superior to cow's milk for an infant?
Cow's milk has too much protein and minerals in it.
The basis for contraceptive pills is ?
They mimic the negative feedback effect of estrogens and progesterone
The basis of pregancy tests kits is the presence of
human chorionic gonadotropin ( HCG) which is secreted by the blastocyst and placenta
What determines whether an organism will be genetically male or female?
What stimulates the descent of the testes
When the number of ovarian follicles decline with age, what happens?
it reduces estrogen levels
Sexual reproduction entails
the union of an egg and sperm to form a zygote
Your lecture instructors name is
The heat los of the neonate is compensated how?
to some extent by the thermal insulation provided by brown fat
This is a true statement
Life expectancy has steadily increased in the last century whereas life span has not.
This statement is false
Cleavage results in daughter cells containing half the number of chromosomes of the parent cell
the body system that degenerates less than any other organ system
individual 16 days old when it consists of three primary germ layers
The skeleton and muscle develop from which primary germ layer?
the first 6 weeks of life
when the blastocyst implants somwhere other than the uterus
the fetus's life support system; disc of tissue attached to the uterine wall on one side and on the other attached to the fetus by way of the umbillical cord.
neonatal assessment of newborns; good predictor of infant survival
the arrangement of blastomeres into the three primary germ layers, ectoderm, mesoderm and endoderm
All changes that occure in the body with the passage of time; growth, development increasing funtional efficeiency and the degerative changes that occur later in life
The study of prenatal development
the process of attachment and embedding of the blastocyst into the endometrium of the uterine wall, begins 6 days after ovulation
the genetic defect characterized by greatly acceleraqted senescence.
The primary germ layer where the epidermis and nervous system develop
a hole in the interatrial septum that allows some fetal blood to bypass the lungs; usually closes at birth
degerative changes in proportion to a persons lifetime exposure to ultraviolet radiation
name of the developing individual at the end of 8 weeks, all of the organ systems are present.
the lack of cerebral activity indicated by a flat EEG for 30 minutes to 24 hours.
the maximum age attainable by humans
the portion of the ectoderm that will develop into the nervous system.
The transparent fetal membrane filled with fluid that surrounds and protects the developing embryo and fetus
the loss of bone
a glycogen-rich secretion of the uterine tubes and endometrial glands; conceptus absorbs this fluid as it travels down the tube and lies free in the uterine cavity before implantation
the degeneration that occures in an organ system after the age of peak functional efficiency
produced when a single egg is fertilized and the cell mass later divides into two which develop independantly, also known as identical twins
trisomy-21 the most survivable trisomy
the single fertilized egg formed after the union of the two pronuclei
agents that cause anatomical deformalites in the fetus; drugs, infectious disease, and radiation are a few
blocks of mesoderm in the embryo that will give rise to the vertebral column, truck nuscles and the dermis of the skin
The first trimester of pregnancy
more than half of the embryos die; most vunerable time to stress, drugs and nutritional deficiencies
a woman giving birth for the first time
secreted by the blastocyst and placenta; its presence in urine can be detected 8-9 days following conception,
a normal head-down position of the fetus from the seventh month until birth
begins when the mentrual fluid is being discharged from the vagina
the usually one folicle per month that matures to the point of ovulation
the collective name for the female external genitalia; pudendum
structured like the penis in some respects; only sensory function, the primary center of sexual stimulation
the layer of the uterine wall responsible for labor contractions
the female gonads that produce egg cells and sex hormones.
encompasses the events that recur every month when pregancy does not occur
the onset of breast development the earliest noticeable sign of puberty
ducts that develop into the female reproductive tract due to the absence of teststerone and MIF
the permenant layer of the endometrium
Male climacteric andropause
the period of declining repreductive function that becomes noticeable , typically in the early 50's
a cell with 23 unpaired chromosomes, sperm and egg
muscular tube that carries sperm from the epididymis into the body during ejaculation; passes upward through spermatic cord
the first phase of human sexual response characterized by vasocongestion, myotonia and increased metabolism
a condition in which boys are born with undescended testes
in male serves to produce sperm and introduce them into the female body; in female produces eggs recieves the sperm and provides for the union of the gamtes.
the period after resolution inwhich it is usually impossible to attain another erection and orgasm.
most common STD in the united states
changes in the DNA structure
Major stages of prenatal development
first trimester- fertilization to 12 weeks
second trimester- 13 to 24 weeks
third trimester- week 25 to birth
first 16 days of development involves three major processes: cleavage, implantation and embryogenesis
the period immediately following birht is a crisis in wich the neonate suddenly must adapt to life outside the mothers body
The first 6 to 8 hours of life
increase in heart and respiratory rate, body temperature drops, physcial activity declines initially then baby often gags on mucus and debris in thier pharynx then stabilizes
Respiratory adaptations of newborn
great effort to inflate lungs for the first few breaths and inflate collapse alveoli, first 2 weeks 45 breaths per minute after which it stabilizes
the study of birth defects
Nondisjunction of autosomes
only three autosomal trisomies are survivable they involve chromosomes 13, 18 and 21: patau syndrome ( trisomy-13), Edward syndrome ( trisomy-18) and downsyndrome (trisomy 21)
Turner syndrome (XO)
egg recieving no X chromosomesbut fertilzed by X carrying sperm. 90 % die at birth
Characteristics of turner syndrome
webbed necks, widely spaced nipples, and secondary sexual characteristics,failure to develop at puberty, sterile
Triplo X syndrome (XXX)
egg recieving 2 X crhomosomes fertilized by X carrying sperm
Klinefelter syndrome ( XXY)
egg recieving 2 X crhomosomes fertilized by Y carrying sperm
Senescence of the Skeletal system
osteopenia that can lead into osteoporosis
Senescense of the Joints
joint disease: less synovial fluid, articular cartilage thinner or absent, breathing difficulties, degeneragion of intervertebral discs
Senescense of the Muscular system
muscular atrophy due to fewer myofribrils, smaller mitochondria, less enzymes, less glycogen, less myoglobin, fewer motor neurons and less efficient sympathetic nervous system
Senescens of the Nervous system
cerebral and neuronal atrophy, degeneration of myelin, plaques can appear on brain, cannot regulate body temperature as well.
Good nutrition and exercise
two good ways to slow down the aging process
What does resistance exercise help with?
it reduces bone fractures in elderly
What does endurance exercise help with?
it reduces body fat, and increases cardiac output and oxygen uptake in elderly
How long should an elderly person exercise to maintain good health?
three to five 20 to 60 minute periods of exercise per week will raise heart rate by 60 to 90 percent
Evolution and senescence
a theory once thought death occurred for the good of the species, to keep available resources for young and healthy.
Natural Selection works through the effects of genes on reproductive rates in which way?
genes that do not affect reproductive rates will neither be favored nor eliminated. aging genes remain with us today.
an average length of life in a given population. an average boy can expect to live 75 years, an average girl can expect to live 81 years.
Death usually occurs as:
a failure of a particular organ followed by a cascade of other organ failures.
When a conceptus arrives in the uterus it is at this stage of development
The acrosomal reaction
The entry of a sperm nucleus into an egg must be preceded by this.
The stage of conceptus that implants in the uterine wall
Chorionic villi develop from ?
Which disease is a result of aneuploidy?
Fetal urine is accumulated and contributed from what area of the uterus?
A theory of sensecence that results from a life time of damage.
Photoaging is a major factor in the senescence of what system?
What is not a common affect of senescence?
Increased herniation of the intervertbral disks
For the first 8 weeks of life, a conceptus is nourished mainly by this
Fetal blood flows throught growths called what ?
Choionic villi which project into the placental sinus
The enzymes with which a sperm penetrates an egg are contained in ?
An organelle called the Acrosome
can result in a cross linking which is a cause of stiffening of the arteries, joints and lenses in old age.
A developing individual is classified as an embryo when?
The three primary germ layers have formed.
Down syndrome (trisomy 21 results from?
Senescence of the immune system makes older people more subject to cancer and infectious disease because a decline in what?
antigen presenting cells and helper T cells
Longest stage of labor is
During birht an infant is normally stimulated to breath by
What is the purpose of the blood testies barrier?
So immune system does not attack spermatogonium from being killed off