book definitons

Question 1

secrete products, called hormones, which are released into the adjacent tissue spaces. The hormones then enter the bloodstream and are carried to other regions of the body to exert their effects

Answer 1

endocrine cells

Question 2

chemical messengers in that certain tissues in the body are signaled by specific hormones to grow or change their cellular activity.

Answer 2

hormones

Question 3

pituitary gland (or hypophysis), pineal gland, gonads (testes and ovaries), placenta, thyroid, parathyroid, adrenal glands, hormone-secreting cells of the digestive tract, kidneys, pancreas, and thymus

Answer 3

endocrine system

Question 4

molecules derived from cholesterol. testes sex hormones (androgens) and ova sex hormones (estrogens and progestogens)
are lipid soluble and thus can pass through the phospholipid bilayer of the plasma membrane easily. Steroid receptors are located within the cytoplasm or the nucleus of target cells. When a steroid hormone binds to its receptor (Fig. 1-5), the steroid/receptor complex undergoes a conformational change that exposes a DNA-binding domain

Answer 4

Steroid hormones

Question 5

substances that promote the development and function of the teste reproductive structures

Answer 5

Androgens

Question 6

stimulate the maturation and function of the ova reproductive structures

Answer 6

Estrogen

Question 7

substances that cause the uterus to be secretory

Answer 7

Progestogens (or progestins)

Question 8

including gonadotropin-releasing hormone (GnRH), follicle-stimulating hormone (FSH), luteinizing hormone (LH) and prolactin (PRL), bind to receptors embedded in the cell membrane of responsive cells.

Answer 8

Protein and peptide hormones

Question 9

This gland synthesizes and secretes hor- mones that travel in the bloodstream and influence many aspects of our body, including the function of other endocrine glands; plays a very important role in our reproductive biology.

Answer 9

pituitary gland

Question 10

an extension of the brain, and it develops as an outgrowth of the portion of the embryonic brain that later becomes the hypothalamus

Answer 10

posterior pituitary gland; also called the neurohypophysis

Question 11

a collection of long dendrites carrying messages to the central nervous system from the periphery.

Answer 11

sensory nerve

Question 12

When one neuron connects with another, information is passed from the first to the second cell; this site of communication is known as a ____

Answer 12

synapse.

Question 13

The axonal ending of the first neuron secretes a chemical called a _____, which travels across the synapse and initiates electrochemical changes leading to nerve impulses in the next neuron.

Answer 13

neurotransmitter

Question 14

similar to a regular neuron in that it can conduct a nerve impulse along its axon; speed of this electrical conduction is, however, much slower than in a regular neuron; are specialized to synthesize large amounts of neurohormones in their cell bodies

Answer 14

neurosecretory neuron

Question 15

The neurohypophysis contains long axons of neurosecretory neurons surrounded by supporting cells. The cell bodies of these axons lie in the part of the brain called the _______. ______ forms the floor and lower walls of the brain (see Fig. 1-6) and contains a fluid-filled cavity, the third ventricle. Regulates body temperature, thirst, hunger, sleep, response to stress, and aggressive and sexual behaviors.

Answer 15

hypothalamus

Question 16

The axons of the neurosecretory neurons in these nuclei then pass down the pituitary stalk (which connects the hypophysis with the brain) and into the neurohypophysis. The granules released by these axons contain two neurohormones: ____ and ______

Answer 16

oxytocin and vasopressin (or antidiuretic hormone).

Question 17

stimulates contractile cells of the mam- mary glands so that milk is ejected from the nipples; causes the smooth muscle of the uterus to contract, thus playing a role in labor and childbirth

Answer 17

Oxytocin

Question 18

adrenal steroid hormones; raises blood sugar levels, reduces inflammation, and combats the effects of stress.

Answer 18

Cortisol

Question 19

plays a role in sperm production in the testes; stimulates the ovaries to produce mature germ cells in their enclosed tissue sacs

Answer 19

follicle stimulating hormone (fsh)

Question 20

hormone that causes interstitial cells in the testes to synthesize and secrete androgens; causes the ovaries to secrete estrogens and progestogens and induces the release of an egg from the ovary; come from cells in the pars distalis, although the pars tuberalis also contains these hormones; play vital roles in the function of the gonads, they are grouped under the term gonadotropic hormones or “gonadotropins.”

Answer 20

luteinizing hormone

Question 21

single releasing hormone increases both LH and FSH secretion from the pituitary; pulsatile pattern of its secretion is essential for gonadotropin secretion, and thus is central to reproductive function; neurons in the hypothalamus modify its secretion through several neurotransmitters such as norepinephrine and dopamine; secretion can be stimulated or inhibited by a complex pattern of neuronal activity in the brain.

Answer 21

gonadotropin-releasing hormone, (GnRH),

Question 22

synthesizes and secretes the hormone melatonin, which can inhibit the reproductive systems

Answer 22

pineal gland

Question 23

aspects of our physiology operate as feedback systems that regulate our internal environment at a steady state; this regulation is called _______

Answer 23

homeostasis

Question 24

Homeostatic control systems in our body operate through ______. In the case of pituitary gland function, a ________ system is one in which secretion of a pituitary hormone to a level above the set point causes a decrease in secretion of that same pituitary hormone into the blood.

Answer 24

negative feedback

Question 25

In reproductive physiology, however, there are also important occurrences of _____, in which the secretion of a pituitary hormone influences the controller center so that secretion of the hormone increases even more.

Answer 25

positive feedback

Question 26

FSH and LH cause secretion of sex hormones by the gonads (testes or ovaries). These steroid hormones (androgens, estrogens, and progestogens) are products (effects) of the action of gonadotropins on the gonads, and it turns out that steroid hormones influence the secretion of LH and FSH by having feedback effects on the systems controlling gonadotropin secretion.\

Answer 26

feedback loop description

Question 27

the administration of moderate amounts of estrogen will lower the secretion of FSH and LH into the blood. This negative feedback effect of estrogen (Fig. 1-16) is even more effective when given in combination with high levels of a progestogen. In fact, this is the reason that combination contraceptive pills contain moderate levels of an estrogen and high levels of a progestogen

Answer 27

negative feedback loop how contraception works

Question 28

In the normal menstrual cycle, high levels of a progestogen and moderate levels of an estrogen in the blood during the luteal phase of the cycle (the period between ovulation and menstruation) lower gonadotropin secretion by negative feedback, thus preventing ovulation at this time

Answer 28

negative feedback loop in a menstrual cycle

Question 29

It may help you to think that the hypothalamus contains a controller center with a gonadostat that works like the thermostat in your heating system. This gona- dostat contains a set point for levels of estrogen and progestogen reaching it from the blood. When levels of these steroids are higher than the set point, the gonado- stat signals the hypophysiotropic area to stop secreting GnRH, and thus secretion of FSH and LH from the adenohypophysis declines. If circulating levels of estrogen and progestogen are below the set point, the gonadostat signals the hypophys- iotropic area to release more GnRH and circulating levels of FSH and LH rise. In males, a similar negative feedback of androgens also acts on the hypothalamus.

Because GnRH neurosecretory neurons probably do not have estrogen, progestogen, or androgen receptors, the negative feedback effects of these steroid hormones must act on regular neurons in the brain, which in turn inhibit GnRH cells. Some of the negative feedback effects of the sex steroids can also act directly on the FSH and LH pituitary cells by decreasing their sensitivity to GnRH.

Answer 29

hypothalamus feedback loop

Question 30

There is, however, a stage in the human menstrual cycle when high levels of estrogen in the blood increase the secretion of LH and FSH from the adenohypophysis, resulting in a “surge” of these gonadotropins (primarily LH) in the blood and the subsequent release of an egg. from the ovary (see Chapter 3). It is important to understand that the negative and positive feedback effects of estrogen have separate and different set points. Therefore, high levels of estrogen in the blood (above the positive-feedback set point) have a positive feedback effect on gonadotropin secretion, whereas mod- erate levels of estrogen (but still above the set point for negative feedback) have a negative effect on gonadotropin secretion (Fig. 1-16). The positive feedback effect of high levels of estrogen operates by stimulating neural activity in the surge center, which then increases GnRH secretion.

Answer 30

positive feedback loop

Question 31

gonad, serves two essential functions in reproduction: development of the gametes (oocytes, or eggs) and the synthesis and release of steroid hormones. The ovaries are paired structures lying on each side of the upper pelvic cavity, against the back of the pelvic wall and near the uterus. These small almond-shaped organs are white or yellowish in color and have a lumpy surface. The mature ovary measures about 2.5 to 5 cm (1–2 in.) in length and 1.5 to 3 cm (0.5–1 in.) wide. The ovaries are innervated by autonomic nerves and receive an especially rich blood supply. They are connected to the uterus and pelvic wall by supportive ligaments.

Answer 31

ovary

Question 32

e luteinized granulosa cells (luteal cells) in this collapsed follicle begin to divide and invade the old antral cavity (Fig. 2-3), thus forming the _____ (Latin for “yellow body”). It is yellow because of the presence of pigment in the luteal cells. Then, blood vessels from the thecal layer grow and penetrate the central luteal cell mass.

Answer 32

corpus luteum

Question 33

is a single, inverted pear-shaped organ situated in the pelvic cavity above the urinary bladder and in front of the rectum (Figs. 2-1 and 2-2). In nulliparous women (those who have never borne a child), the uterus is about 7.5 cm (3 in.) long, 5 cm (2 in.) wide, and 1.75 cm (1 in.) thick. In multiparous women (those who have previously borne children), the uterus is larger and its shape is more variable.

Answer 33

uterus

Question 34

Its muscle fibers increase in length and number during pregnancy. Internal to the myometrium is the layer of the uterus that lines the uterine cavity

Answer 34

endometrium

Question 35

the small channel, within the cervix, that connects the vagina with the uterine cavity.

Answer 35

cervical canal

Question 36

The uterus is subject to infectious organisms entering through the vagina. Some bacteria, such as those associated with sexually transmitted diseases, can cause uterine infection and inflammation that can spread to the oviducts. Such an infection can be dangerous to the fetus during pregnancy and can lead to oviductal scarring and infertility

Answer 36

Pelvic Infection

Question 37

a 10-cm (4-in.)-long tube that lies between the urinary bladder and rectum (Figs. 2-1 and 2-2). It functions as a passageway for the menstrual flow, as a receptacle for the penis during coitus, and as part of the birth canal. The wall of the vagina has folds that allow it to stretch during coitus or childbirth; it is normally collapsed. The vaginal canal leads from the vulva (external genitalia) to the external cervical os. The opening of the external cervical os into the vagina is circumscribed by a recess called the fornix. This recess allows support for a diaphragm contraceptive (see Chapter 14).

Answer 37

vagina

Question 38

is a cushion of fatty tissue, covered by skin and pubic hair, that lies over the pubic symphysis. The skin of this area has many touch receptors and only a few pressure receptors. The distribution and the amount of pubic hair vary in different individuals. Usually the pubic hair forms the shape of an inverted pyramid. In about 25% of women, this hair extends in a line up to the navel.

Answer 38

mons pubis

Question 39

fleshy folds of tissue that extend down from the mons pubis and surround the vaginal and urethral orifices. These folds contain fat, and the pigmented skin has some pubic hair, sweat and oil glands, and fewer touch and pressure receptors than the mons pubis. are homologous to the male scrotum, i.e., they are derived embryologically from the same tissue

Answer 39

labia majora

Question 40

are paired folds of smooth tissue underlying the labia majora. They range from light pink to brownish black in color in different individuals. In a sexually unstimulated condition, these tissues cover the vaginal and ure- thral openings, but upon sexual arousal they become more open. The hairless skin of the labia minora has oil glands (but no sweat glands) and a few touch and pressure receptors. In older women or in women who have low estrogen levels, the skin of the labia minora becomes thinner and loses surface moisture.

Answer 40

labia minora

Question 41

most of this cavity is occupied by the opening of the vagina, the vaginal introitus

Answer 41

vestibule

Question 42

introitus often is covered partially by a membrane of connective tissue; This tissue often is torn during first coitus, accompanied by minor pain and bleeding; In rare cases, a wall of tissue completely blocks the introitus,

Answer 42

hymen

Question 43

Anterior to the vaginal introitus; This is where urine passes from the body. Below and to either side of the urethral ori-fice are openings of two small ducts leading to the paired lesser vestibular glands

Answer 43

Urethral Orifice

Question 44

lesser vestibular gland; homologous to the male prostate gland; secrete a small amount of fluid; at each side of the introitus are openings of another pair of glands

Answer 44

Skene’s glands

Question 45

greater vestibular glands; these glands secrete mucus and are homologous to the bulbourethral glands of a testes person; can form a cyst or abscess as the result of infection.

Answer 45

(Bartholin’s glands)

Question 46

lies at the anterior junction of the two labia minora, above the urethral orifice and at the lower border of the pubic bone; average length is about 1 to 1.5 cm (0.5 in.) and it is about 0.5 cm in diameter; considerable individual variation in size; cylindrical structure has a shaft and glans (enlarged end); is partially homologous to the penis

Answer 46

clitoris

Question 47

contains a pair of corpora cavernosa, spongy cylinders of tissue that fill with blood and cause the clitoris to erect slightly during sexual arousal; homogenous to shaft of penis on testes person

Answer 47

clitoral shaft,

Question 48

homologous to a similar structure covering the glans of the penis

Answer 48

clitoral prepuce,

Question 49

paired skin glands positioned over ribs two through six on the chest. Their function is to secrete milk during breast-feeding and they also serve as a stimulus for sexual arousal; `These glands evolved from sweat glands, and so milk is really modified sweat!

Answer 49

mammary glands

Question 50

is a highly coordinated series of events that results in ovula- tion of a single follicle and preparation of the uterus to receive the embryo after fertilization. This cycle is driven by activity of the hypothalamic GnRH pulse generator and surge center. Gonadotropins released from the pituitary induce changes in steroid secretion by the ovaries. In addition to these hormonal fluctu- ations, structural changes occur in the ovaries and the uterine endometrium

Answer 50

menstrual cycle

Question 51

customary to designate the first day of the cycle (day 1) as the first day of this phase; this is the day on which menstruation begins, and it is chosen as a starting point because a person is more aware of this day than any other in the cycle; can last from 1 to 6 days, but usually lasts 4 or 5 days.

Answer 51

menstrual (“destructive”) phase

Question 52

begins at the end of menstruation, or about day 6 if menstruation lasts 5 days; characterized by the rapid growth of ovarian follicles; during this phase, the ovaries continue growth that began during the menstrual phase and then secrete estradiol, which in turn causes growth and thickening of the uterine endometrium; this phase continues until ovulation, which occurs on about day 14 of a 28-day cycle and on day 16 of a 30-day cycle; day 13, usually only one large Graafian follicle, 20 to 25 mm in diameter, is present in only one ovary; this large follicle appears like a blister on the surface of one ovary; ovulation usually occurs about 14 days before the onset of the next menstruation (day 1 of the next cycle)

Answer 52

follicular phase

Question 53

lasts from ovulation to the beginning of menstruation; it is during this phase that the corpus luteum, which is formed from the wall of the ovulated follicle; secretes estradiol and progesterone, which prepare the uterus for the arrival of an embryo; the ovum disintegrates if fertilization does not occur, and its remains are washed out of the body in the menstrual flow; if fertilization does occur, the embryo may implant (embed) in the uterine lining and further menstrual cycles are inhibited during pregnancy.

Answer 53

luteal phase

Question 54

Estradiol is secreted by the larger follicles in each ovary, including those that may later become atretic. The rise in estrogen causes the uterine endometrium to proliferate (thicken) during the _____. Thus, with reference to the uterus, this phase of the menstrual cycle is often called the proliferative phase. Under estrogenic influence, uterine glands begin to enlarge (Fig. 3-2). The endometrium becomes more richly supplied with blood vessels, and water accu- mulates between cells in the tissues, a condition known as edema. In addition, the smooth muscle of the myometrium begins to contract mildly in a rhythmic fash- ion, although a woman usually is not aware of these slight contractions.

Answer 54

follicular phase

Question 55

moderate circulating levels of estradiol have a negative feedback effect on GnRH secretion. At the beginning of the follicular phase, when estradiol levels are low, FSH levels rise because of the absence of negative feedback by estradiol on GnRH secretion. After estradiol reaches moderately high levels in the midfollicular phase, it exerts negative feedback on GnRH secretion, and FSH levels begin to decline. Human ovarian follicles contain a substance (inhibin) that inhibits FSH (but not LH) secretion, and this substance may also exert negative feedback effects. A related ovarian peptide called activin stimulates FSH secretion. The ovary also produces follistatin, a glycoprotein that inhibits FSH secretion by binding to activin and neutralizing its effects.

Answer 55

GnRH negative feedback during the follicular phase

Question 56

In the last days of the follicular phase, estradiol levels are very high (secreted from several large follicles in each ovary) and now exert a positive feedback on GnRH secretion. This increase in GnRH causes the LH surge on day 14. GnRH (and FSH and LH) pulses increase 10 times in amplitude and occur every 30 min during the LH surge (Fig. 3-4).

Answer 56

GnRH positive feedback during follicular phase

Question 57

During the luteal phase, the uterine endometrium becomes thick and spongy (Fig. 3-2) and its glands secrete nutrients that will be used by the embryo—if one is conceived (see Chapter 10). Because the uterus is secretory during the luteal phase, this part of the menstrual cycle is termed the ______ when referring to endometrial physiology. During this phase, the uterine smooth mus- cle contracts less frequently than during the follicular phase.

Answer 57

secretory phase

Question 58

Pain during menstruation is called _____ or menstrual cramps, and it occurs during strong contractions of the uterine smooth muscle. It is common for muscle contraction to be painful and take the form of cramps when blood supply to that muscle is low, such as in the uterus during menstruation. The cause of these cramps is not clear, but prostaglandins present in the menstrual fluid may stimulate the uterine smooth muscles and cause their contraction, thus helping to evacuate the uterus. These prostaglandins, in combination with reduced progesterone levels, may actually initiate menstruation, and it is only when prostaglandin levels are unusually high that menstrual cramping occurs. Evidence that prostaglandins cause menstrual cramps is that aspirin, which inhibits the synthesis of prostaglandins, relieves these cramps and associated back pain in many women

Answer 58

dysmenorrhea

Question 59

the absence of menstruation when it normally should occur

Answer 59

Amenorrhea

Question 60

occurs when an adult woman skips one or a few cycles

Answer 60

Oligomenorrhea

Question 61

The human menstrual cycle, which usually is 25 to 35 days long, consists of menstrual, follicular, and luteal phases. Cyclic secretion of hormones from the hypothalamus (gonadotropin-releasing hormone), anterior pituitary gland (FSH, LH), and ovaries (estradiol, progesterone) controls the cycle, and negative and positive feedback plays an important role. The mechanisms causing regression of the corpus luteum at the end of each cycle are not yet understood. Methods used to detect ovulation in the home or laboratory are not reliable in predicting when ovulation will occur.

Answer 61

menstruation summary

Question 62

oval, with a length of about 4.0 cm (1.5 in.) and a width of 2.5 cm

Answer 62

teste

Question 63

Sex is determined by chromosomes and is established at the time an egg is fertilized by a sperm
Females, each diploid cell has 46 chromosomes (23 pairs), including 22 pairs of autosomes (nonsex chromosomes) and 1 pair of sex chromosomes. The sex chromosomes in females are XX, so the chromosomal type of female cells is designated as 46:XX. This occurs when a haploid (23:X) egg is fertilized by a haploid (23:X) sperm. Male somatic cells are 46:XY, which occurs when a 23:X egg is fertilized by a 23:Y sperm.

Answer 63

chromosomal sex

Question 64

require the moist environments of membranes in the so-called “transitional zones” of the body—those that occur at openings between the external and the internal body surfaces. These transitional zones include the vulva, vagina, and urethra of the female; the penis and urethra of the male; and the mouth, oral cavity, eyes, and anus of both sexes.

Answer 64

sti (sexually transmitted infections)

Question 65

In the remaining 25% of women who exhibit symptoms, the first sign usually is the appearance of a clear or whitish fluid discharge from the vagina (infection or inflammation of the vagina, called vaginitis). This discharge soon changes to a yellowish or greenish color, i.e., it becomes a purulent discharge (a pus-filled discharge). The vaginal wall can become quite irritated at this time, and bleeding may occur with vaginal intercourse. Eventually, the infection can reach the cervix; infection and inflammation of this organ (cervicitis) contribute to the purulent discharge. A discharge can also come from the urethra (urethritis). Urination can become difficult and painful when urethritis is present. Also, the bacteria can reach the urinary bladder, causing infection (cystitis)

Answer 65

symptoms of gonorrhea in people with vaginas

Question 66

symptoms may take as long as 30 days after infection to appear. The first signs usually are a purulent discharge from the urethra and redness of the glans of the penis. Urination can become painful and difficult, and scar tissue can form in the urethra. Men can also have painful erections, pain in the groin region, and a low fever. If not treated, the infection can spread in about 3 weeks to the urinary bladder and prostate gland and can infect these organs. The epididymides also can become infected, and in some cases, the testes themselves become infected and inflamed (orchitis), sometimes leading to infertility.

Answer 66

symptoms of gonorrhea in people with penises

Question 67

two rounds of antibiotics

Answer 67

treatment for gonorrhea

Question 68

appears as a single sore called a chancre (pronounced shang’ker) at the place where the bacteria first entered the body. This is a round, ulcer-like sore with a hard raised edge and a soft center.

Answer 68

first sign of syphilis