A&p2 rat 19, RAT 21, RAT 20
What are the functions of the testes?
(1) produce sperm cells and (2) secrete androgen hormones, most importantly testosterone.
What is a homologous pair? What is a sister chromatids? Can you locate them in the images?
- A set of maternal and paternal chromosomes with the same genes - Identical copies of a replicated chromosome
What are the regions of the ovaries? What is found in each region?
- As in many other organs, the superficial portion of the ovary is the cortex and the deeper portion is the medulla -The ovarian cortex is the site of oogenesis, the production of female gametes. In females, gametes are produced inside saclike structures called follicles, which develop and mature along with the gametes. -The ovarian medulla houses blood vessels, lymphatic vessels, and nerves.
List some male secondary sexual characteristics.
- Testosterone also triggers the development of male secondary sex characteristics, which are features induced in nonreproductive organs that are associated with adult males. Male secondary sex characteristics develop primarily at puberty, but may continue to develop into early adulthood in some males. They include the following: -growth of pubic, axillary, and facial hair; -enhanced hair growth on the chest or other body areas in some men; -an enlarged larynx and thicker vocal cords, resulting in a noticeable laryngeal prominence ("Adam's apple") and deepening voice; and -thickened skin and increased secretions of sebaceous glands (the oilier skin often results in acne).
What hormonal changes occur during male climacteric?
- These changes are usually gradual and typically begin in the early 50s, but may or may not produce noticeable changes in all men. The size and weight of the testes may decrease and the number of sustentacular and interstitial cells may begin to decline. - Probably the most noticeable change for most men during climacteric is enlargement of the prostate gland. This compresses the prostatic urethra, which often causes difficulty with urination.
Describe the size and location of the uterine tubes. What are some alternate names for this organ?
- also called fallopian tubes or oviducts, form the first part of the duct system of the female reproductive system - Each uterine tube is approximately 10 cm (3.9 in.) long and extends medially from the ovary to the superior and lateral region of the uterus.
What are some other effects of female hormones?
- estrogens promotes maturation of sex organs, development of external genitalia, development of breast tissue, preservation of bone mass and maintenance of vascular health. -also helps with maintaining a pregnancy Estrogens and, to a lesser degree, progesterone also stimulate the development of female secondary sex characteristics. These effects include maturation of the sex organs, development of the external genitalia, and maintenance of anatomical features unique to adult females, such as breast development and fat accumulation around the hips and thighs. In addition, progesterone is responsible for maintaining a pregnancy if fertilization occurs Estrogens also have far-reaching effects on other tissues, many of which are beneficial. For example, estrogens reduce the breakdown of bone by inhibiting osteoclasts, which helps to prevent osteoporosis. They also have protective effects on the cardiovascular system—they increase the level of HDLs ("good" cholesterol) in the blood while decreasing the level of LDLs ("bad" cholesterol). However, not all of estrogens' effects on the cardiovascular system are always beneficial, as they promote blood coagulation. This accounts for the increased risk of developing blood clots in women who are taking estrogen-containing medications such as oral contraceptives.
What hormonal changes occur during puberty?
At puberty, the hypothalamus becomes much less sensitive to inhibition by estrogens and progesterone, and the GnRH level increases. GnRH stimulates the HPG axis, and blood estrogens and progesterone levels begin to rise, resulting in the appearance of female secondary sex characteristics.
Describe the two basic compartments where fluid is found.
1) intracellular compartment: the fluid compartment located within cells that contains cytosol or intracellular fluid 2) extracellular compartment: the fluid compartment located outside cells that contains extracellular fluid
diploid
2 sets of chromosomes
Between puberty to menopause, about how many primary oocytes are stimulated to continue development each month?
20-30 primary oocytes are stimulated to continue development
How many seminiferous tubules are in each lobule?
4
What is the product of meiosis?
4 haploid daughter cells
How many chromosomes are in a human cell?
46
Would these changes favor capillary filtration or capillary reabsorption?
????
Define dehydration.
A condition characterized by a decreased volume and increased concentration of the extracellular fluid
What is chromatin?
A long, thin strand of DNA and it's associated proteins
What is hypocalcemia? How does this impact neurons?
A plasma calcium ion concentration lower than 8.7 mg/dl is considered to be hypocalcemia. The condition is generally due to a decrease in PTH, ineffective PTH (as occurs with renal failure), and vitamin D deficiency, although many other factors can contribute to it. Hypocalcemia has the opposite effect on neurons from hypercalcemia—the neurons become hyperexcitable, as more sodium ions enter and depolarize the neurons, stimulating action potentials.
Describe the primordial follicle.
A single layer of squamous follicular cells surrounds the primary oocyte. At birth, each ovary has approximately 1-2 million primordial follicles, each follicle containing a primary oocyte.
What determines the osmotic pressure of a solution?
A solution's osmotic pressure is determined by its osmolarity, or the number of solute particles present in the solution. This means that water moves toward the solution with the higher osmolarity, or the higher number of solute particles.
What is the collective term for the external female genitalia?
AKA vulva -The external genitalia include the mons pubis, labia majora, labia minora, clitoris, and structures associated with the vestibule. Although the external genitalia are often referred to as the "vagina," the vagina is located internally and is not part of the external genitalia.
What is metabolic water?
AKA water of oxidation -water produced as a byproduct of metabolic reactions
What are the two categories of sources of acids and bases in the body?
Acids and bases in the body come from two main sources: (1) those that are formed as a normal part of metabolic processes, and (2) those that are ingested as a part of the diet.
What happens at the venous end of a capillary?
At the capillary's venular end, the plasma has a high osmotic pressure but a lower hydrostatic pressure. As a result, most of the water lost from the plasma at the arteriolar end is drawn back into the capillary by osmosis. The capillary does lose a small amount of water, and this is returned to the plasma via the lymphatic system
Describe the stages of oogenesis and when each occurs.
Before birth. The stem cells of females, called oogonia (oh′-oh-GOH-nee-ah; singular, oogonium), undergo their mitotic divisions before birth, during months 2-7 of the fetal period. This means that a female produces all the oogonia she will ever make before she has even been born. At about seven months of fetal development, the total number of oogonia is about 7 million; however, this number drops sharply as many of the oogonia begin to die. The remaining 1-2 million oogonia begin to undergo meiosis I, at which point they are called primary oocytes. The primary oocytes proceed as far as prophase I, after which their development is arrested. Childhood. The primary oocytes remain in prophase I and do not develop further by meiosis until a girl reaches puberty. At that time, rising hormone levels trigger the start of the ovarian cycle. Note that during childhood, primary oocytes continue to degenerate—by the time a girl reaches puberty, the number has dropped to around 300,000. Puberty to Menopause. About once a month after puberty, 20-30 primary oocytes are stimulated to continue development. Usually one primary oocyte (or more in some women) will complete meiosis I to produce two haploid cells that are very different in size. The smaller cell, the first polar body, contains DNA but very little cytoplasm and often degenerates. The larger cell, the secondary oocyte, contains DNA and most of the cytoplasm plus absorbed extracellular fluid. The extra cytoplasm in the secondary oocyte ensures that if it is fertilized, it will have adequate nutrients for its 4- to 7-day journey toward the uterus. The large amount of cytoplasm is also the reason why only the secondary oocyte has the potential to become an ovum.
Trace the path of the ductus deferens.
Carries semen from the epididymis through the inguinal canal to the pelvic cavity
What happens to cells during overhydration?
Cells exposed to the hypotonic ECF swell as water enters the cells by osmosis
What is a chemical buffer system?
Chemical buffers are, as the name suggests, chemical systems that work to buffer fluids in the body -a system that resists changes in the pH of the body's fluids; consists of a weak acid and its conjugate base
What are some common causes of dehydration?
Common causes for dehydration include profuse sweating, prolonged diarrhea and/or vomiting, certain endocrine conditions, and overuse of diuretics.
What happens when the level of calcium ions in the ECF rises?
Conversely, when the calcium ion level rises, calcium ions are deposited into bone by osteoblasts, fewer are reabsorbed from the filtrate, and fewer are absorbed from the small intestine.
What forms the bulb of the penis? Label the bulb of the penis.
Corpus spongiosum
What is the smooth muscle layer in the scrotum called?
Dartos muscle
What happens to cells?
Although hypernatremia can impact the depolarization of excitable cells, its most immediate, obvious effects are due to the osmotic imbalances that it causes. As occurs in most cases of dehydration, water moves out of the cell into the hypertonic ECF, leading to a reduced volume of cytosol and to cell crenation. This affects cells throughout the body, and can lead to the same symptoms we listed for dehydration. Treatment revolves around restoring hydration, which will normalize the sodium ion concentration.
Can water move freely between compartments?
Although solute movement between fluid compartments is restricted, water generally moves freely between them.
Why is this more complicated in females than in males?
Another difference is in the structure of the gametes. As you just read, when a secondary oocyte forms, it receives most of the nutrient-rich cytoplasm, and the extra set of DNA is discarded in the polar body. The nutrients in the cytoplasm help support the developing conceptus until it begins obtaining nutrients from the mother. The situation differs for a sperm cell: It only needs to deliver genetic material to the developing oocyte, so excess cytoplasm is removed during spermiogenesis to keep the sperm cell small.
What is menarche?
Approximately 2 years after the onset of puberty, females experience their first episode of menstrual bleeding, called menarche
What changes occur as a result of the changing hormone levels?
As a result, ovulation does not occur and the blood concentration of estrogens declines sharply, although many women continue to synthesize some estrogen from adrenal androgens. However, secretions of FSH and LH from the pituitary are no longer inhibited, so these hormones may be continuously released for some time. The lower concentration of estrogens and progesterone may change the female secondary sex characteristics. The breasts, vagina, uterus, and uterine tubes may shrink, and the pubic and axillary hair may thin. Often bone density decreases, which may lead to osteoporosis, and the skin becomes thinner.
Describe the secondary follicle.
As childhood continues, the primary follicles develop into secondary follicles. The wall of the follicle thickens, and the deeper granulosa cells secrete follicular fluid, which forms small pockets and increases the overall size of the follicle. In addition, the granulosa cells grow, enlarge, and stimulate nearby cells in the ovary to form a layer of thecal cells around the follicle. Granulosa cells produce estrogens from the secretions of the thecal cells. The primary oocyte is still growing slowly at this stage.
What impact does excess calcium ions have on depolarization? Why?
As we discussed earlier, an elevated calcium ion concentration in the ECF makes neurons less permeable to sodium ions, which diminishes the ability of the neurons to depolarize. This in turn decreases the neurons' activity, leading to mental sluggishness, reduced reflex activity, and weak muscle activity (due to lack of stimulation from motor neurons).
Why is consuming pure water potentially problematic for someone who is dehydrated? How can this potentially be prevented?
Dehydration may be treated by consuming pure water, but this should be approached with caution. If water is consumed in moderate amounts, it will mildly dilute the ECF, making it slightly hypotonic to the cytosol. This will trigger a shift of water back into the cells, rehydrating them. However, if large amounts of water are consumed in a short period of time, the ECF can become overly dilute, causing too much water to enter the cells and resulting in cellular swelling. For this reason, treating dehydration with sports drinks is preferable in many cases, as sports drinks contain glucose and electrolytes, making them hypertonic to pure water.
What is an allele?
Different forms of a gene
Describe the primary follicle. What is the shape of the granulosa cells?
During childhood, many of the primordial follicles begin developing into primary follicles. As this occurs, the follicular cells change in shape from flattened to cuboidal, at which point we call them granulosa cells. Two important structures appear in the primary follicles: microvilli and thecal cells. Microvilli develop in the oocyte and grow into the surrounding granulosa cells and form a connection. Part of this connection is a glycoprotein-rich area called the zona pellucida, which becomes important if the oocyte is later fertilized (see Chapter 27). Microvilli also increase the surface area available for the granulosa cells to transfer materials to the growing primary oocyte through gap junctions. Only a small number of the primary follicles will continue development.
Describe the changes that occur leading to an erection.
During sexual arousal, a parasympathetic reflex triggers the release of nitric oxide (NO) from blood vessel endothelial cells. This relaxes smooth muscle in the walls of the arterioles of the penis, dilating them, and within the blood sinuses in erectile tissue, which allows large amounts of blood to enter the tissue. The combination of increased blood flow and widening blood sinuses results in an erection. The erection is maintained, at least partially, by the compression of the veins that drain the penis. Note that the corpus spongiosum does not become as rigid as the corpora cavernosa, which allows the urethra to remain open during ejaculation so that sperm and semen can pass.
What changes occur in females during the sexual response?
During sexual excitement, the vaginal mucosa, vestibule, and breasts engorge with blood; the clitoris and nipples become erect; and increased activity of the vaginal mucosa and vestibular glands lubricates the vestibule. For the most part, these events are similar to the erection phase in men. Tactile and psychological stimuli, mediated along autonomic pathways, promote sexual excitement.
What happens during the menstrual phase?
During the menstrual phase, the uterus sheds the stratum functionalis, resulting in menstruation.
What happens during the proliferative phase?
During the proliferative phase, a new stratum functionalis develops with endometrial glands and spiral arteries and veins. As this new layer thickens (proliferates), its endometrial glands enlarge and its spiral arteries and veins increase in number. Cervical mucus is thick and sticky until just before ovulation, when it thins to facilitate the passage of sperm into the uterus. At the end of the proliferative phase around day 14, ovulation occurs.
What happens during the secretory phase?
During the secretory phase, the spiral arteries convert the stratum functionalis to secretory mucosa and endometrial glands secrete a nutritious glycogen-rich fluid, also known as uterine milk, into the uterine cavity to sustain the conceptus.
Describe the size and location of the ovaries. Why do they appear bumpy?
Each ovary weighs only about 6-8 g and is about the size of a walnut in women who are actively releasing ova on a monthly cycle. These organs appear relatively smooth before puberty, but as a woman matures, they take on a bumpy appearance due to scars left behind when ova are released approximately once each month.
What are the regions of a mature sperm? Label them in the image above.
Each sperm cell has head, midpiece, and tail regions and is about 55-60 μm (0.0021-0.0024 in.) long and about 3 μm (0.0001 in.) wide (see Figure 26.8a). The head includes the nucleus and the acrosome and very little cytoplasm; the midpiece contains the mitochondria; and the tail is a flagellum surrounded by the plasma membrane. The tail moves in a mature sperm cell because of ATP provided by the mitochondria of the midpiece.
What is a zygote?
Earliest stage of human development, consists of a single cell formed from the fusion of an ovum and a sperm cell
What can cause edema?
Edema can have many causes, including high hydrostatic pressure, as seen with hypertension, a decrease in the return of venous blood to the heart, and/or excess sodium ion retention; low colloid osmotic pressure; removal of lymphatic vessels; or release of inflammatory mediators.
How large is the prostate gland?
Egg-sized
What is ejaculation? What are the two phases of ejaculation?
Ejaculation is the process by which semen is expelled from the penis. Although erection is under parasympathetic control, ejaculation is under sympathetic control. It actually occurs in two stages, emission and expulsion.
Where does sperm travel next? What structures mark the beginning of this duct? The end of this duct? Through which gland does this duct travel?
Ejaculatory duct, junction of the ampulla of the ductus deferens and the duct of an accessory gland called the seminal vesicle, Each ejaculatory duct then travels through another accessory gland, the prostate gland, and empties into the urethra
What occurs during emission? Expulsion?
Emission is the movement of sperm and testicular fluid, as well as secretions from the prostate gland and seminal vesicle, into the urethra. As semen accumulates in the urethra with the increase in sexual tension, sensory impulses are stimulated and pass into the sacral portion of the spinal cord. Motor neurons from the spinal cord stimulate skeletal muscles at the base of the erectile columns of the penis to rhythmically contract, resulting in expulsion of the semen from the urethra.
What stimuli can lead to an erection?
Erection can occur because of a variety of sexual stimuli, including touch; mechanical stimulation of the penis; and erotic sights, sounds, and smells.
What is the function of the oviduct? How does it carry out this function?
Externally, they are covered by the peritoneum and are supported along their length by part of the broad ligament. Internally, they are lined by smooth muscle and simple columnar epithelium, with cells that are both ciliated and nonciliated.
What is the name of the process in which the female gamete is produced?
Female gametes are produced by the process of oogenesis. -oogenesis: the process of female gamete, or ova, production in females Oogenesis begins with an oogonium that has 46 chromosomes, and produces 1 secondary oocyte that has 23 chromosomes; when fertilized, this secondary oocyte becomes an ovum with 46 chromosomes.
Describe the three ligaments that hold the ovaries in place.
First is the broad ligament, a large, flat ligament that attaches to the ovaries, uterine tubes, and uterus and connects them to the bony pelvis (you can see this attachment to the pelvis in Figure 26.10b). Next is the ovarian ligament, which connects the medial surface of the ovary to the uterus, near the attachment of the uterine tube. Finally, the suspensory ligament (or infundibulopelvic ligament; in-fun-DIB-yoo-loh-pel′-vik) connects the lateral surface of the ovary to the pelvic wall. Notice in Figure 26.11 that this ligament carries the ovarian artery and ovarian vein.
What is first-tier control?
First-tier control. The hypothalamus releases gonadotropin-releasing hormone (GnRH).
What is the first-tier control in the hypothalamic-pituitary-gonadal (HPG) axis?
First-tier control. The hypothalamus secretes gonadotropin-releasing hormone (GnRH).
What happens if a strong base is added to a solution of pure water?
For example, see what happens when a strong base such as sodium hydroxide (NaOH) is added to water, as shown in the upper right illustration in Figure 25.9b. In this unbuffered solution, the released hydroxide ions remove many of the hydrogen ions from the solution and raise its pH, making it very basic
If potassium ion levels are critical, then why do you not die when you eat a banana?
Fortunately, several mechanisms within the endocrine and urinary systems help to prevent this from happening. For one, hormones such as insulin, aldosterone, and epinephrine stimulate the uptake of potassium ions by cells. This shifts the newly ingested potassium ions into the intracellular compartment.
What do they become as they mature?
From childhood through menopause, primordial follicles progressively mature first to primary follicles
The condition respiratory alkalosis is caused by a loss of carbon dioxide through the lungs due to hyperventilation.
Generally, this results from psychological states that increase the rate of breathing. The condition may also occur when an individual is at extremely high altitudes and the low PO2 of the atmosphere triggers hyperventilation.
Why is there normally no net osmotic movement between the ECF and the cytosol? What can change this?
As we just described, the ECF and cytosol generally have the same osmotic pressure. Such solutions, which are referred to as isotonic, have the same ability to cause water movement by osmosis. So, there is usually no net osmotic movement of water between the two solutions. However, when the ECF's solute concentration is altered, its osmotic pressure changes, and so its ability to cause water movement by osmosis also changes. There are two possible types of ECF solute variations, hypotonic and hypertonic, and they cause water movement as follows: -Hypotonic ECF causes a cell to gain water. The ECF is hypotonic to the cytosol when it has a lower osmotic pressure than the cytosol and so a lesser ability to cause water movement by osmosis. In this case, it's the cytosol that has a greater osmotic pressure, which gives it a greater ability to drive osmosis. For this reason, a cell in a hypotonic ECF gains water and will swell. -Hypertonic ECF causes a cell to lose water. The ECF is hypertonic to the cytosol when it has a higher osmotic pressure than that of the cytosol and so has a greater ability to cause water movement by osmosis. So, a cell in a hypertonic ECF loses water because it leaves the cytosol and enters the ECF. This causes the cell to shrivel, or crenate.
Describe the changing hormone levels during the uterine cycle.
As you can see, at the beginning of the menstrual phase, FSH and LH levels are beginning to rise. Ovarian hormones, however, are at their lowest normal levels until day 5, at which point the growing ovarian follicles start to produce more estrogens. As the proliferative phase begins, the rising levels of estrogens cause a new stratum functionalis to generate and trigger endometrial cells to synthesize progesterone receptors. The high levels of estrogens trigger release of more FSH and LH, and their levels peak around day 14, which causes ovulation. At the start of the secretory phase, the level of progesterone from the corpus luteum begins to rise, while the amount of estrogen secreted decreases. The high progesterone level and falling levels of estrogens inhibit the anterior pituitary, which, as you can see in the graph, leads to low amounts of LH and FSH. This progesterone also stimulates the continuing development of the stratum functionalis during the secretory phase.
Assuming a 28-day cycle, when does the follicular, ovulation, and luteal phase occur?
Assuming an ovarian cycle of 28 days, the follicular phase extends from the 1st to the 14th day of the cycle, ovulation typically occurs on day 14, and the luteal phase extends from the 14th to the 28th day.
What are the regions of the uterine tube? Describe the fimbriae.
At its proximal end, the uterine tube connects to the uterus in a constricted region called the isthmus. The distal end of each uterine tube expands as it curves around the ovary, forming the ampulla, which is where fertilization of an oocyte normally occurs. The ampulla connects to the infundibulum, an open funnel-shaped structure. At the end of the infundibulum are ciliated, finger-like projections known as fimbriae (FIM-bree-aye) that drape over the ovary and "catch" an oocyte that is released from an ovary during a process known as ovulation.
Describe the vesicular (tertiary) follicle. Typically, how many follicles become a tertiary follicle each month? What is the name of the fluid-filled cavity?
At puberty, rising levels of FSH and LH stimulate a group of secondary follicles to continue maturation. Usually only one follicle—the dominant follicle—completes this process and becomes a vesicular follicle. As you can see in Figure 26.15, in a vesicular follicle, the smaller pockets of follicular fluid from a secondary follicle merge to form a single large cavity called the antrum. The primary oocyte and its surrounding capsule of granulosa cells, known as cumulus cells, project into the antrum. As the vesicular follicle continues to enlarge, it may reach 15-25 mm (0.6-1.0 in.) in diameter and create a bulge in the surface of the ovary. At this point, the primary oocyte, which has been suspended in prophase I, completes meiosis I to form the secondary oocyte and the first polar body. However, it is then suspended in metaphase II and will not complete meiosis unless fertilization occurs. Keep in mind that the maturation of any one individual oocyte and follicle likely takes 3-4 cycles to complete.
What are the signs and symptoms of dehydration?
Initially, a person becoming dehydrated will experience a dry mouth and thirst. This situation progresses to dryness of the skin and decreased urine production (called oliguria; ohl′-ih- GYU-ree-uh); eventually, fever may develop and organ function is impaired. The condition, and its associated electrolyte imbalances, is fatal if hydration is not restored.
Label the vagina and the fornix in the image.
It parallels the anterior urethra, lying between the urinary bladder and the rectum. The superior end of the vaginal canal surrounds the external os of the cervix and produces a recess called the vaginal fornix (shown in Figure 26.11). The wall of the vagina is covered with transverse ridges, or rugae, which stimulate the penis during intercourse. Generally, the lumen of the vagina is quite small and, except where it is held open by the cervix, its walls touch one another. However, the vagina stretches considerably during intercourse and childbirth.
What changes in hormone levels occur during this time?
It takes place because the number of primary follicles left to respond to FSH and LH is quite low after approximately three decades of ovarian cycles and also because of atresia—a process in which immature follicles degenerate and are resorbed during the follicular phase of the menstrual cycle. Those follicles that remain in the ovaries are less responsive to gonadotropins, and so less estrogen and progesterone are secreted.
What is third-tier control?
Third-tier control. The ovaries are the target organ of FSH and LH. LH stimulates thecal cells in the follicle to secrete androgens, which diffuse through the basement membrane to the granulosa cells. FSH stimulates granulosa cells in follicles to convert these androgens to estrogens. FSH also stimulates granulosa cells to secrete inhibin.
What is the third-tier control? What is the effect of the hormones produced?
Third-tier control. The testes are the target organs of FSH and LH. LH stimulates the interstitial cells to produce testosterone. FSH stimulates the sustentacular cells to secrete androgen-binding protein (ABP), and the hormone inhibin.
What is the ovarian cycle?
This cycle consists of three main phases: the follicular, ovulation, and luteal phases.
Would these changes favor capillary filtration or capillary reabsorption?
This has increased its hydrostatic pressure but also made the plasma hypotonic by diluting it, which has decreased its osmotic pressure. Both situations—a higher hydrostatic pressure and a lower osmotic pressure—will cause water to move out of the plasma and into the interstitial fluid. This then increases the hydrostatic pressure and decreases the osmotic pressure of the interstitial fluid, both of which drive water into the cytosol. As a result, the cell swells.
Why is sodium such an important osmotic particle in the ECF?
This is due in large part to two factors: (1) the Na+/K+ ATPase pump, which uses ATP to pump sodium ions out of the cytosol against their concentration gradient; and (2) the relatively low permeability of the plasma membrane to sodium ions, which prevents these ions from leaking back into the cytosol in large numbers. This high extracellular concentration of sodium ions makes them one of the most important types of osmotic particles in the ECF.
What is sexual intercourse? What are some other terms for it?
This is usually accomplished by sexual intercourse, also called copulation or coitus (KOY-tus), most commonly defined as the insertion of the male penis into the copulatory organ of the female, the vagina.
What hormone triggers the secretion of potassium?
This makes potassium ion secretion possible only in the distal tubule and collecting system. As you have learned, this is under the control of aldosterone, which triggers secretion of potassium ions (and hydrogen ions) and reabsorption of sodium ions.
Alkalosis is defined as a body fluid pH greater than 7.45 (alkalemia refers specifically to an elevated blood pH).
This occurs when more base ions are added than the buffers can handle or when the number of hydrogen ions in the body fluids decreases. Alkalosis increases the excitability of neurons, and so they fire action potentials inappropriately. This results in sensory symptoms such as numbness and tingling and motor symptoms such as muscle twitches or tetanic contractions. Untreated, alkalosis can lead to seizures and death due to sustained contractions of respiratory muscles.
What percentage of bicarbonate ions are typically reabsorbed?
This process accounts for reabsorption of nearly 100% of the bicarbonate ions in the filtrate and secretion of large numbers of hydrogen ions.
What hormonal changes occur during puberty?
Throughout a boy's childhood, testosterone from the testes and androgens from the adrenal cortex are secreted in low, but sufficient, amounts to inhibit GnRH release from the hypothalamus. This continues until puberty, when the hypothalamus becomes much less sensitive to inhibition by the androgens, causing the GnRH level to increase. GnRH stimulates the HPG axis, and the blood testosterone level begins to rise, triggering spermatogenesis and the appearance of male secondary sex characteristics. In most boys, puberty begins between 12 and 14 years of age, but this age varies. Usually within a few years after the onset of puberty, the hormone levels stabilize. As soon as spermatogenesis begins, males are capable of sexual reproduction, even if hormone levels are still fluctuating.
Label two uterine ligaments, the three regions of the uterus, and the opening to the uterus on the image.
Like the ovaries, the uterus is supported by several ligaments: inferiorly by the lateral cervical ligaments, which extend from the cervix and superior vagina to the lateral walls of the pelvis; posteriorly by the paired uterosacral ligaments (yoo′-ter-oh-SAYK-ruhl), which connect the uterus to the sacrum; anteriorly by the round ligaments, which connect the uterus to the anterior body wall (you can see this attachment in Figure 26.10); and laterally by the broad ligaments. In addition to these ligaments, the uterus also receives a great deal of support from the muscles of the pelvic floor. There are three regions of the uterus: the main portion, or body; the rounded region superior to the entrance of the uterine tubes, called the fundus; and the cervix, the narrow neck that projects into the vagina inferiorly. The most inferior portion of the cervix, which serves as the entrance into the uterus, is known as the external os. It is this portion of the cervix that is generally observed during a pelvic examination. Glands in the mucosa of the cervical canal secrete mucus that covers the external os, acting as a protective plug.
Review: this section begins with a list of calcium functions. How many do you remember from previous chapters? Jot down the functions that you forgot about.
Main components of osseous tissue 🡪 give bone its hardness and resistance to compression Required for muscle contraction and plateau phase of cardiac action potential/intracellular signaling Blood clotting Neuronal synaptic transmission etc.
What is male climacteric?
Male climacteric (kly-MAK-ter-ik), or andropause, is the period in which reproductive functions begin to decline in men.
How large are the bulbourethral glands? When does it release its secretion? What is the function of its secretion?
Marble sized, secrete a thick alkaline mucus-like fluid that helps neutralize any acidic urine remaining in the urethra prior to ejaculation
What happens to the RMP with mild/moderate hyperkalemia?
Mild hyperkalemia alters the resting membrane potential—the excess of potassium ions in the ECF causes fewer potassium ions to leave the cell through leak channels. This means that the cell retains more positive charges, and as a result the resting membrane potential is more positive at rest than is normally the case
What can cause mild hyperkalemia?
Mild hyperkalemia is generally the result of renal failure or aldosterone insufficiency. It may also be due to widespread tissue damage that occurs with severe burns or trauma, as the damaged cells rupture and release their potassium ions into the ECF. Other potential causes include drugs such as aldosterone blockers and one commonly used for heart failure
What color is prostatic fluids? What do the enzymes found in prostatic fluid do? Describe the pH.
Milky, dissolve the clot of semen that initially forms in the female reproductive tract so that the sperm can move deeper into the tract; akaline
Mitosis vs. Meiosis
Mitosis is normal cell division everywhere Meiosis happens only in sex cells (gametes)
How is overhydration normally prevented?
Normally, when water is consumed, hypotonic hydration is prevented by a decline in ADH production, which leads to loss of the excess water in the urine.
Do the acids and bases we consume in our food have a big impact on pH homeostasis?
Note that although these foods do contribute some amounts of acids and bases to the body, they represent an exceedingly small minority that have essentially no effect on overall pH—the vast majority of acids and bases come from the body's own metabolic reactions, not from outside sources.
What are signs/symptoms of hypernatremia?
Note that sometimes hypernatremia can be accompanied by overhydration. This occurs when the hypernatremia is due to rapid ingestion of excess table salt or increased secretion of aldosterone, both of which increase water retention by the kidneys. Rehydration will be little help in these cases; for this reason, it's critical for a clinician to determine the primary cause of the hypernatremia so the proper course of treatment can be initiated.
Under normal conditions, how do the hydrostatic and osmotic pressures of the interstitial fluid and cytosol compare?
Notice that under normal conditions, the interstitial fluid's hydrostatic and osmotic pressures are very close to those of the cytosol, so not much of a gradient exists between the two compartments and there is no significant net movement of water between them
What happens if a strong acid is added to a buffered solution?
Now see what happens when we add the same acid to a solution buffered by sodium bicarbonate, shown at the bottom left in Figure 25.9a. Notice that here (after sodium bicarbonate dissociates), the hydrogen ion from the strong acid is accepted by the bicarbonate ion, forming carbonic acid. Since carbonic acid is a weak acid, it doesn't release its hydrogen ions as readily, minimizing any pH changes in the solution.
What are the spiral arteries?
Numerous endometrial (uterine) glands change in length as endometrial thickness changes. The main vascular supply of the uterus comes from the uterine arteries, which arise from the internal iliac arteries in the pelvis. After branching several times, they eventually form the spiral (coiled) arteries of the stratum functionalis.
Why would this value vary from person to person?
Of course, most people don't fit the profile of the standard man, and so total body water differs from this value. An individual's body mass, age, sex, and amount of adipose tissue all affect total body water. -In addition, infants of both sexes have a higher total body water, averaging about 65%, whereas individuals over 60 years of age average a total body water of about 52% for men and 46% for women.
What is resolution? What is the refractory period?
Orgasm and ejaculation are quickly followed by resolution, or relaxation. Blood vessels in the erectile tissues and blood sinuses constrict, forcing blood out of the penis, which soon becomes flaccid again. After ejaculation, a latent period, or refractory period, follows; during this time, ranging from minutes to hours, a man is unable to achieve another orgasm. The refractory period tends to get longer as men age.
What is orgasm?
Orgasm refers to the time period during which feelings of pleasure are experienced. In males, this coincides with ejaculation. - the time period during which feelings of pleasure are experienced during sexual intercourse.
What are other stimuli that can trigger thirst?
Other stimuli that can trigger thirst include a decreased plasma volume and the hormone angiotensin-II
Define overhydration.
Overhydration, also known as hypotonic hydration, results when the volume of the ECF increases and its osmotic pressure falls
What is the external portion of the penis called?
Penis and scrotum- perineum
What is the purpose of the polar body?
Polar body: the smaller cell that is produced during meiosis of oogenesis; contains DNA but very little cytoplasm and generally does not divide further - extra set of DNA is discarded in the polar body
Why would an enlarged prostate gland cause a problem with urination?
Pushes on urethra
What is the HPG axis?
Regulation of ovarian function requires a rhythmic fluctuation of hormones from the hypothalamus, the anterior pituitary, and the ovaries themselves. These hormones interact via negative feedback in the same hypothalamic-pituitary-gonadal (HPG) axis that operates in males, with the exception of a positive feedback mechanism that triggers ovulation.
Name two extracellular fluids. What is the main difference between the compositions of these two fluids?
Two of the fluids that we have discussed at length are plasma, the fluid portion of the blood, and interstitial fluid, the fluid in the spaces between the cells. Plasma accounts for approximately 8% (3 liters) of the total body water, and interstitial fluid for about 32% (13 liters) -The main difference in the composition of the two fluids is in protein content: Plasma has a much higher protein content than interstitial fluid, which has virtually no proteins.
Normally the amount of carbon dioxide expired is the same as the amount of _______________
Under normal conditions, the amount of carbon dioxide expired by the lungs matches the amount of carbon dioxide produced by metabolic reactions, which is why your respiratory rate doesn't remain constant.
How many follicles typically develop into a mature follicle each month?
Under the control of this cycle, each month a group of secondary follicles is stimulated to progress to the next stage of development, the vesicular follicle, or tertiary follicle. Again, most of these secondary follicles undergo atresia and die, and usually only one remains.
Where does sperm travel next? What are the three regions of this structure?
Urethra, prostatic, membranous, and spongy urethra
How many will complete development?
Usually one primary oocyte (or more in some women) will complete meiosis I to produce two haploid cells that are very different in size.
Each type of acid-base disturbance has a characteristic set of ABG findings, which are as follows:
Respiratory acidosis. The primary abnormality seen with respiratory acidosis is an elevated arterial PCO2PCO2 and lower than normal blood pH. If the bicarbonate ion level is elevated, then renal compensation has begun and the acidosis is partially compensated. Metabolic acidosis. The values for metabolic acidosis are slightly more complex, but the general rule of thumb is that you will have a decreased pH and lower bicarbonate ion level in the blood, although this might not always be the case. The PCO2PCO2 is also generally lower than normal because of respiratory compensation. Due to the rapid effects of respiratory compensation, most cases of metabolic acidosis are partially compensated. Respiratory alkalosis. The main findings with respiratory alkalosis are fairly straightforward—an elevated blood pH and a low PCO2PCO2. If the bicarbonate ion level is also low, this signifies partial compensation by the kidneys. Metabolic alkalosis. Metabolic alkalosis shows an elevated blood pH and a high bicarbonate ion level. If respiratory compensation has occurred, the PCO2PCO2 will be elevated.
What happens if two follicles mature and both secondary oocytes are fertilized?
Usually only one vesicular follicle is at the peak of maturation when ovulation occurs; however, sometimes more than one vesicular follicle releases a secondary oocyte. This phenomenon may result in fraternal twins, or nonidentical twins. It occurs more commonly in some families and also increases in frequency with advancing maternal age.
In which type of follicle does the primary oocyte complete meiosis I to become a secondary oocyte?
Vesicular (tertiary) follicle: -At this point, the primary oocyte, which has been suspended in prophase I, completes meiosis I to form the secondary oocyte and the first polar body.
Why are calcium and phosphate ions discussed together?
We cannot discuss calcium ions without also discussing phosphate ions (PO43−)(PO4 3−) because they are found together in hydroxyapatite crystals. The inorganic portion of bone cannot be built unless both ions are present.
What is an isosmotic fluid imbalance?
When ECF remains isotonic to cytosol; plasma osmotic pressure unchanged - include hypovolemia and hypervolemia
What happens to the hydrogen and bicarbonate ions that are formed in the reaction above?
When carbonic acid is formed in erythrocytes, much of it dissociates into bicarbonate and hydrogen ions. The hydrogen ions that form bind to hemoglobin, which buffers the cytosol of erythrocytes. The bicarbonate ions, however, are transported into the plasma, where they buffer fixed acids.
What are some signs & symptoms of hypocalcemia?
When hypocalcemia is severe, neurons begin firing spontaneously, leading to repetitive stimulation of skeletal muscles and tetanic (sustained) contractions. For example, the characteristic carpopedal spasm of hypocalcemia
Why does our thirst go away before the plasma osmolarity is restored?
When plasma osmolarity decreases, water moves back into the osmoreceptors and thirst is inhibited. Interestingly, however, we feel relieved of thirst as soon as we ingest liquids, well before they are absorbed and have the chance to affect osmoreceptors. This is believed to be due to **receptors in the pharynx** that detect the ingestion of liquid. Such a response is critical to preventing excessive liquid intake. If the liquid were not detected until ECF osmolarity decreased to the normal range—which takes about 30-60 minutes—one could continue drinking and overhydration could result.
What hormone decreases sodium ion reabsorption?
When secretion of both hormones decreases, the number of sodium ions (as well as the amount of water) reabsorbed decreases. Another hormone that influences sodium ion balance is atrial natriuretic peptide (ANP), which decreases sodium ion (and water) reabsorption. Together, these three hormones maintain a relatively stable plasma sodium ion concentration in the face of sometimes significant swings in sodium ion intake.
Review: Why is sodium critical to the function of excitable cells like neurons and muscle cells?
When sodium ion channels open, the sodium ions follow their concentration gradient and rush into the cell 🡪 causes depolarization (key event in exciting cells)
What happens if the hydrostatic pressure of plasma decreases?
When the hydrostatic pressure of the plasma decreases, we don't normally see water move from the interstitial fluid into the capillary, because the plasma's hydrostatic pressure is still significantly higher than that of the interstitial fluid. Instead, we simply find that less water moves out of the capillary and into the interstitial fluid. We generally only see the gradient reversed—that is, water moving from the interstitial fluid into the plasma—in extreme cases, such as during severe blood loss (known as hypovolemic shock).
What happens if the hydrostatic pressure of plasma increases?
When the hydrostatic pressure of the plasma increases due to a higher water volume, more water is pushed out of the capillary into the interstitial fluid. This in turn increases the hydrostatic pressure of the interstitial fluid above that of the cytosol, creating a gradient that drives water into the cell.
Why does your respiratory rate increase when you are exercising and decrease when you are sedentary?
When you are physically active, glycolytic catabolism and oxidative catabolism occur more rapidly and more carbon dioxide is generated. As a result, your respiratory rate increases to match the higher level of carbon dioxide production. The opposite is also true—when you are sedentary, you generate less carbon dioxide and so your respiratory rate decreases.
What color is the fluid? Name three components of seminal fluid. Describe the pH of seminal fluid.
Yellowish, alkaline, fructose, prostaglandins, and coagulating proteins/ enzymes
Why is water balance dependent on sodium balance?
Yet in spite of this significant sodium ion intake, the concentration of sodium ions in the ECF remains stable, thanks to several mechanisms. This is critical not only to sodium ion balance but also to fluid balance, as water reabsorption in the kidneys depends on a gradient consisting largely of sodium ions in the interstitial fluid
What is the percentage of water in a "standard man"?
You may have heard or read that the human body is composed of about 60% water. However, this value refers to the amount of water in the "standard man," a reference point that considers the standard values for a 20- to 30-year-old 70-kg (154-lb) male of European descent.
What is the inguinal canal and the inguinal ring?
a passageway into the abdomen, opening to the inguinal canal
What is hyperkalemia?
a plasma potassium ion concentration above 4.5 mEq/l. Hyperkalemia is arguably one of the most dangerous electrolyte imbalances; indeed, a high dose of potassium ions can cause death almost immediately.
What is an ovarian follicle (this may be called simply "follicle" in this chapter)?
a small structure inside the ovarian cortex that contains a developing oocyte
What is hypernatremia? What is its primary cause?
a sodium ion concentration in the blood above 145 mEq/l. The most common cause of hypernatremia is actually dehydration.
What is a strong acid? A weak acid?
a strong acid is one that releases most of its hydrogen ions when placed in water, which lowers the pH of the solution. A weak acid, however, releases relatively few hydrogen ions in solution, and so has a much smaller impact on pH.
What is a strong base? A weak base?
a strong base is one that binds and removes a great number of hydrogen ions from the solution, increasing the solution's pH. A weak base binds relatively few hydrogen ions in a solution and so has less impact on its pH.
What is an electrolyte? List examples of some of the common electrolytes discussed in this course.
a substance that dissociates into ions when placed in water cations and anions (na and cl and k)
What is the corpus albicans?
a whitish knot of scar tissue that forms as the corpus luteum degrades -When levels of hormones secreted by the corpus luteum decline, macrophages within the ovary invade the corpus luteum and degrade it while fibroblasts lay down collagen fibers. These actions reduce the corpus luteum to the corpus albicans, a whitish knot of scar tissue (albus = "white"). This event marks the end of one ovarian cycle.
About how long is the ductus epididymis? How does that support the function of the epididymis?
about 6 m (19.7 ft) , allows ample time for sperm to mature, and also permits sperm to be stored for several months if ejaculation does not occur
What are accessory reproductive organs?
additional organs and structures that contribute to the functioning of the reproductive system
What is the enlarged end of the ductus deferens called?
ampulla
____________ merge to form the seminal vesicle. The seminal vesicle produces seminal fluid.
ampulla of the ductus deferens and the duct of an accessory gland
What is the most potent trigger for thirst?
an increase in the osmolarity of the plasma.
What is a buffer?
buffer system: a chemical system that resists changes in pH and prevents large swings in the pH when acid or base is added to the solution
What is mitosis? What is the product of mitosis? Which cells undergo mitosis? Which cells undergo meiosis?
cell division undergone by all somatic, or body, cells that are capable of division, 2 daughter cells cells destined to become gametes
What is a base? What is the most common base in the body?
chemical that accepts a hydrogen ion in a solution bicarbonate ion?
What is an acid?
chemical that dissociates in water to release a hydrogen ion (H+)
Where does sperm flow next? After that?
Rete testis, then efferent ductules to enter the epididymis
What is second-tier control?
Second-tier control. GnRH stimulates the anterior pituitary to release FSH and LH.
What is the second-tier control?
Second-tier control. GnRH stimulates the anterior pituitary to secrete the gonadotropins: follicle-stimulating hormone (FSH) and luteinizing hormone (LOO-tee′- uh-nyz-ing) (LH), also called interstitial cell-stimulating hormone (ICSH) in males.
What divides the scrotum into two compartments? What is the raphe?
Septum, ridgelike seam at midline
What can cause severe hyperkalemia?
Severe hyperkalemia is almost always due to ingestion or administration of excess potassium ions. This can be intentional, as with a lethal injection, or accidental, as occurs when a medical professional mistakenly gives the wrong dose of potassium salts.
Simply put, what happens when the level of calcium ions in the ECF falls? (list 3)
Simply put, when the level of calcium ions in the ECF falls, calcium ions are released from the bone by osteoclasts, more are reabsorbed from the filtrate in the kidneys, and more are absorbed from ingested food and liquids in the small intestine.
How much water do we need to drink? Does drinking excess water help people lose weight? NO
Since on average a person loses about 2.5 liters per day, then water gains should equal about 2.5 liters per day. -So this leaves only about 1.5 liters of water that we need to drink. Of course, this amount will vary with activity. A person engaged in strenuous physical activity can lose 4-5 liters of fluid through sweating, and naturally this volume needs to be replaced to prevent serious imbalances.
How long does it take for a follicle to mature into a vesicular follicle?
So it will take about 90-120 days for the dominant follicle to mature to a vesicular follicle with a secondary oocyte.
What happens to the corpus luteum if a pregnancy occurs?
So, if pregnancy does occur, the corpus luteum will persist for approximately 3 months to produce hormones.
What are signs/symptoms of hyponatremia?
Sometimes hyponatremia can exist with dehydration, which occurs with a primary loss of sodium ions and water molecules. This can be caused by prolonged vomiting and/or diarrhea, decreased aldosterone secretion, and diuretic overuse. In such cases, the osmolarity of the ECF is generally nearly isotonic to the cytosol, so isotonic saline is used instead of hypertonic saline.
Describe the process of spermatogenesis.
Spermatogenesis occurs in the seminiferous tubules of the testes through the division of spermatogenic, or sperm-forming, cells. Spermatogonia (sper-mat′-oh-GOHN-ee-ah; singular, spermatogonium), the stem cells that begin the process, are diploid cells with 46 chromosomes. They are found along the basement membrane of the seminiferous tubules, as you can see in Spermatogenesis begins with a spermatogonium that has 46 chromosomes, and produces 4 spermatids that have 23 chromosomes each.
What are the two cells found in the seminiferous tubules? What is the function of each?
Spermatogenic, sperm-forming cells, and sustentacular cells, which support the production of sperm by production of testicular fluid, which contain nutrients for sperm cells
What structures are found in the spermatic cord? What is the name of the smooth muscle found here?
Supporting structure of the male reproductive system extending from the scrotum to the inguinal canal, cremaster muscle
What are the male gonads? Where are they located? What is the name of the structure they are located in?
Testes, in the scrotum located outside the abdominopelvic cavity
What artery serves the testicles? What is the name of the veins that drains blood from the testicles? Describe the structure of this vein.
Testicular artery, pampiniform venous plexus, network of veins
What is obligatory water loss? What volume is a typical daily obligatory water loss?
The amount of urine that must be produced daily irrespective of fluid intake to excrete wastes and other solutes. -The obligatory water loss for most people is about 500 ml, even if a person has not taken in any water at all.
What are some primary mechanisms to prevent imbalances of fluid homeostasis?
The amount of water in your body may increase and decrease throughout the day. Generally, the body compensates for these changes by altering urine output and there is no noticeable disturbance in fluid balance. However, some conditions can either overwhelm the compensatory mechanisms or prevent the body from compensating at all. Certain imbalances can lead to a change in the osmolarity of the ECF, whereas others produce an isosmotic state, meaning that the ECF has the same tonicity as the cytosol. In this section, we look at both types of imbalances more closely.
ConceptBOOST>>> Why does the amount of water in the body affect the sodium ion concentration?
The answer is that it actually doesn't have any effect on the absolute number of sodium ions. Instead, it changes the concentration of sodium ions in body fluids, meaning the percentage of sodium ions relative to water molecules. -The concentration of sodium ions in the body's fluids is determined by both the absolute number of sodium ions in the body fluids and the number of water molecules. So anything that abnormally increases or decreases the number of sodium ions and/or the number of water molecules can cause a sodium ion imbalance. This potential imbalance comes in two forms: hypernatremia, an elevated sodium ion concentration, and hyponatremia, a decreased sodium ion concentration.
What are the basic phases of the male sexual response?
The basic phases of the male sexual response include erection and ejaculation. Erection is the enlargement and stiffening of the penis, which allows the penis to enter the vagina. An erection results when the erectile tissue in the penis becomes engorged with blood. Normally, blood vessels in the penis that supply erectile tissue are constricted, and the penis is in a flaccid, or relaxed, state.
What is the biggest source of metabolic acids?
The biggest source of metabolic acids is carbon dioxide, which is a byproduct of glucose catabolism -carbon dioxide is known as volatile acid because in solution it is able to change states from carbonic acid back to carbon dioxide gas. This allows carbon dioxide to be eliminated from the body through both the lungs and the kidneys.
Normally, the body's buffer systems ensure that the pH of body fluids remains within a narrow range, even when acids or bases are added or lost. But when these buffer systems are overwhelmed by a significant loss or gain of acids or bases, they can fail, resulting in a pH imbalance. The two basic types of pH imbalance are acidosis and alkalosis.
The body attempts to correct both types of imbalances through a process called compensation, which involves respiratory compensation and/or renal compensation.
We define the condition respiratory acidosis as a decrease in the pH of body fluids due to excess carbon dioxide.
The carbon dioxide excess happens when ventilation decreases, which is known as hypoventilation (see Chapter 21). Hypoventilation leads to the accumulation of carbon dioxide because less of it is being exhaled. This interferes with the carbonic acid-bicarbonate ion buffer system and causes a shift toward excessive carbonic acid, lowering the pH of the blood. There are three general causes of respiratory acidosis: suppressed ventilation from brainstem dysfunction, blockage of air passages in the lungs, and decreased gas exchange in the alveoli. Whatever the cause, the respiratory and urinary systems attempt to compensate for the acidosis.
Which of these are found in a chemical buffer system? How does this minimize pH changes?
consist of a weak acid and its conjugate weak base, function to resist large swings in pH. -When a strong acid is added to a solution, the weak base of the buffer system binds the released hydrogen ions and removes them from solution. When a strong base is added to a solution, the buffer system's weak acid releases its hydrogen ions to bind the base ions. Both situations minimize pH changes and help maintain acid-base homeostasis. The buffering capacity of the body's fluids is known as the alkaline reserve. When the alkaline reserve is depleted, acid-base imbalances can result.
Chloride ion regulation is coupled to the regulation of what other ion?
The concentration of chloride ions in the ECF is mostly determined by the kidneys, where the reabsorption of these ions is largely coupled to that of sodium ions. Chloride ions follow sodium ions passively from the filtrate to the ECF due to the electrical gradient created by sodium ion reabsorption. In addition, several transporters move the two ions together.
For each of the following, determine if the concentration is higher in the ECF or the ICF. Sodium ions Chloride ions Calcium ions Proteins Potassium ions
The concentrations of sodium, chloride, calcium, and bicarbonate ions are much higher in the ECF than in the cytosol. In contrast, proteins and potassium, magnesium, sulfate, and monohydrogen phosphate (HPO42−) ions have a much higher concentration in the cytosol than in the ECF.
What is the first phase of the ovarian cycle? When does it occur in a woman's lifetime?
The development of follicles is a process that occurs continuously from childhood to menopause. During the follicular phase, the follicle grows and develops.
Label the dorsal and the deep arteries in the picture on the previous page. Note their location. (Notice that the term dorsal makes more sense for the erect penis)
The dorsal arteries supply the penile skin, fascia, and corpus spongiosum, and the deep arteries feed the corpora cavernosa.
Explain the effect of hydrostatic pressure with respect to water movement.
The effect of hydrostatic pressure on water movement with respect to the plasma is relatively simple. Hydrostatic pressure in this context is just the force of the water on the capillary wall. The hydrostatic pressure of the plasma is higher than that of the interstitial fluid, so normally water is forced out of the capillary.
What are the three bodies of erectile tissue in the penis called? What are they composed of? Label them in the image.
corpora (singular, corpus), covered by sheaths of dense fibrous connective tissue
Why is fluid balance so important in determining electrolyte balance?
critical factor that helps to determine electrolyte balance
What are the borders of the perineum? Label them in the image. Also label the urogenital triangle and the anal triangle.
diamond-shaped area between the thighs bordered by the pubic symphysis anteriorly, the ischial tuberosities laterally, and the coccyx posteriorly
What is an ion?
dissolve into the water of the body's fluids, where they have a number of important roles
What happens during ovulation?
during ovulation, a ova is expelled from the ovary. it is then picked up by the fimbriae and then moves into the uterine tube. the peristalsis and the beating of cilia moves the ova towards the uterus.
What is the glans penis?
end of the penis, called the glans penis, which is where the external urethral orifice is located
What typically happens to the prostate gland with age?
enlarges
What ducts does the sperm pass through after leaving the testis?
epididymis, ductus deferens, ejaculatory duct, and urethra
What is the usual site of fertilization?
fertilization, which begins when a sperm cell binds to and penetrates the plasma membrane of an ova, occurs in the uterine tube (usually ampulla).
What are the primary sex organs? What do they produce?
gonads- testes and ovaries that produce sex cells or gametes
What are the regions of the epididymis?
head, body, tail
What is hypervolemia? What is a common example?
hypervolemia: fluid overload, or too much fluid in the blood; ECF volume increases without change in osmotic pressure Example is edema (swlling)
What part of the body controls the thirst mechanism?
hypothalamus
What is hypovolemia? What can cause hypovolemia? What are some signs and symptoms of hypovolemia?
hypovolemia: volume depletion is a state of decreased blood volume or diminished blood fluid -This type of fluid imbalance is known as hypovolemia, and, if untreated, it can lead to shock, organ failure, and death due to extremely low blood pressure. Generally, if the blood products cannot be immediately replaced, isotonic fluids are administered to help restore ECF volume.
What are the effects?
The estrogens and inhibin produced have various effects throughout the reproductive system. Estrogens stimulate the dominant follicle to continue developing into a vesicular follicle. The granulosa cells of the new vesicular follicle continue to produce estrogens in increasing amounts. In most cases, a rising concentration of the target hormone would trigger a negative feedback loop; that is, you might expect the rising levels of estrogens to cause the anterior pituitary to decrease LH release. However, the opposite occurs: When the granulosa cells eventually produce enough estrogens, they exert positive feedback on the anterior pituitary, and trigger a large increase in LH release. This increase is known as the LH surge. The LH surge, accompanied by a rise in FSH secretion, triggers ovulation. The resulting corpus luteum produces additional progesterone, estrogens, and inhibin.
What typically happens to the ovulated oocyte?
The fimbriae of the uterine tube sweep the ovarian surface, allowing them to "catch" the ovulated secondary oocyte. The oocyte is then carried into the uterine tube, where a combination of peristalsis and the beating of the cilia moves the oocyte toward the uterus. Nonciliated cells in the uterine tube produce a mucus-like secretion that keeps the oocyte moist and nourished. Note that because the ovary is not directly attached to the uterine tube, the fimbriae may not pick up the oocyte, in which case it is released into the peritoneal cavity. After the oocyte is released, the vesicular follicle collapses and ruptured vessels bleed into the antrum. The remaining structure is known as a ruptured follicle.
What are the first follicles that formed called? What do they contain?
The first follicles formed in the female fetus are called primordial follicles. Each one contains one primary oocyte.
What percentage of total body fluid is found inside of cells?
The fluid within the intracellular compartment is, of course, cytosol (or intracellular fluid [ICF]), which accounts for about 60% of the body's fluids, or about 26 liters.
What happens if a strong base is added to a buffered solution?
The hydrogen ion binds to the hydroxide ion released from sodium hydroxide, forming water and a molecule of sodium bicarbonate. The bicarbonate ion is a weak base and will not remove significant numbers of hydrogen ions from the solution.
What direction does water move based on hydrostatic gradients?
The hydrostatic pressure gradient, or the force that the fluid exerts on cells, tends to result in water moving from an area of higher hydrostatic pressure to one with lower hydrostatic pressure.
Describe the nerve supply to the penis
innervated by many sensory and motor fibers, including both sympathetic and parasympathetic nerves.
What are the two basic ways that the kidneys aid in acid-base balance?
The kidneys work with the lungs in two ways to determine the number of hydrogen ions and base ions in the blood. First, the kidneys can excrete fixed acids that the lungs cannot excrete, such as lactic acid, ketones, phosphoric acid, uric acid, and ammonium ions (NH4+). About 25% of the body's hydrogen ions are eliminated in this manner. Second, the kidneys contribute to acid-base homeostasis by controlling the concentration of bicarbonate ions in the blood. -Generally, the kidneys reabsorb all the bicarbonate ions from the filtrate. Recall, though, that there are no true transport mechanisms to move bicarbonate ions from the filtrate into the tubule cells. For this reason, other, more roundabout methods for reabsorption are needed. In addition, the kidneys can actually manufacture new bicarbonate ions when the pH of the blood falls, and secrete bicarbonate ions when the pH of the blood rises.
What cells are found between the seminiferous tubules?
interstitial cells or leydig cells
What is the endometrium?
lining of the uterus The endometrium has two main strata, or layers.
What is electrolyte balance?
maintained through the principle of mass balance, by which the amount of electrolytes gained through the diet is equal to that lost from the body via various routes
What is semen? What composes the majority of semen? What makes the second largest contribution? How much does sperm contribute?
milky white, somewhat sticky mixture of sperm and fluids from the testes, seminal vesicles, prostate, bulbourethral glands, and urethral glands sperm compose 5%
What is semen?
mixture of sperm and seminal fluid
Hypokalemia
most commonly caused by diuretics -causes the RMP to hyperpolarize, and so cells are difficult to stimulate
When does the secondary oocyte complete meiosis? *****
only if fertilization occurs
The ovulated oocyte is in which stage of development?
ovulation phase -Stage 5
What is a physiological buffer system? What are the two physiological buffer systems?
physiological systems are functions of organ systems that work to buffer fluids. -the respiratory system and urinary system are the body's physiological buffer systems
What is the anatomical term for foreskin? What is the name of the procedure where this is removed?
prepuce circumcision
What pump helps maintain the concentration gradient of potassium ions?
primarily to the actions of the Na+/K+ pump
What is ejaculation?
process by which semen is expelled from the penis
What is capacitation?
process, sperm undergo changes that enable them to penetrate and fertilize an immature female gamete
Review: potassium ions are critical in maintaining the ___________ _______________ potential.
resting membrane
What hormones are secreted by the corpus luteum?
secretes progesterone and some estrogens
What are the functions of the epididymis?
site of sperm maturation and storage and is filled with many ductules
What is spermatogenesis?
sperm cells develop via a process known as spermatogenesis Spermatogenesis (sper-mat′-oh-JEN-uh-sis) is the process of male gamete, or sperm cell, development. It begins at puberty and continues throughout life. Every day, a healthy young adult male makes about 400 million sperm.
What forms when seminiferous tubules merge?
straight tubule
What two forces determine the direction of the movement of water?
that the direction in which water moves between compartments is influenced by two pressure gradients: hydrostatic pressure and osmotic pressure, another example of the Gradients Core Principle (p. 28).
List some female secondary sexual characteristics.
the appearance of pubic and axillary hair; an increase in the overall amount of adipose tissue in the subcutaneous layer, with additional deposits in the breasts and around the hips and thighs; increased secretions of sebaceous glands (the oilier skin often results in acne); and skeletal changes, including increased height and widening pelvis.
What is the ovarian cycle?
the monthly series of events associated with the maturation of an ooctye and its follicle in an ovary -at puberty, a female begins the ovarian cycle
hypothalamic-pituitary-gonadal (HPG) axis definition
the multi-tiered feedback loops of the hormones of the hypothalamus, anterior pituitary, and gonads
What is ovulation?
the process by which the ovary expels a secondary oocyte -In the ovulation phase, generally simply called ovulation, the secondary oocyte and associated granulosa cells, called the corona radiata, are released from the ovary.
What do primary follicles become as they mature?
then to secondary follicles
What forms the crus? Label the crura.
two corpora cavernosa split to form the two crura
When do the mitotic divisions take place in females?
undergo their mitotic divisions before birth, during months 2-7 of the fetal period.
What causes the penis to enlarge during sexual excitement?
vascular spaces fill with blood, which causes the penis to enlarge and become rigid. This event, called erection
What is the main component of all body fluids?
water
What is the purpose of the secondary oocyte?
The larger cell, the secondary oocyte, contains DNA and most of the cytoplasm plus absorbed extracellular fluid. The extra cytoplasm in the secondary oocyte ensures that if it is fertilized, it will have adequate nutrients for its 4- to 7-day journey toward the uterus. The large amount of cytoplasm is also the reason why only the secondary oocyte has the potential to become an ovum.
What happens to the remainder of the follicle in the ovary after ovulation?
The luteal phase (LOO-tee-uhl) is the period in which the remnants of the ruptured follicle become an endocrine organ called the corpus luteum.
Describe the process of spermiogenesis.
The maturation process of sperm is called spermiogenesis (sper-mee′-oh-JEN-uh-sis) and involves changing the size and shape of the cell. Spermiogenesis begins in the testes as the spermatid elongates and sheds excess cytoplasm (step 4 in Figure 26.7). As it continues, the following occur (step 5): A structure known as the acrosome (AK-roh-sohm), which contains digestive enzymes and helps fertilize the female gamete, forms over the nucleus; more mitochondria are produced and move to their positions around the beginning part of the flagellum; microtubules in the cell form the flagellum, or tail; and cells lose their connections to sustentacular cells and are released into the lumen of the seminiferous tubule.
Describe the structure of the female external genitalia.
The mons pubis (mahnz PYOO-bis) is a fatty, rounded area overlying the pubic symphysis that is covered with hair after puberty. Posterior to the mons pubis are two elongated, fatty protective skin folds, the labia majora (LAY-bee-uh), which enclose two thinner skin folds called the labia minora. Enclosed within the labia minora is a recess known as the vestibule. The vestibule contains the urethral orifice and vaginal orifice; the paraurethral glands (pehr-uh-yoo-REETH-ruhl), which discharge mucus into the urethra; and the openings of the greater vestibular glands (Bartholin's glands), which release a small amount of mucus into the vestibule, helping to lubricate the opening of the vagina during intercourse. -Anterior to the vestibule is the clitoris (KLIT-ur-us), a small, protruding structure composed of erectile tissue. It corresponds to the corpora cavernosa of the penis and is important in the female sexual response. Just as in the penis, erectile tissue of the clitoris becomes engorged with blood and is innervated by many sensory, motor and autonomic fibers. Tactile, pressure, and temperature receptors are abundant here as well, and are also important for sexual stimulation.
What is the pH range for body fluids, including blood? (You should know these numbers!)
The normal hydrogen ion concentration of body fluids is equal to a pH range of about 7.35-7.45. The body must maintain the pH within this narrow, slightly alkaline, range because even a slight deviation can have disastrous consequences for our cells. Blood pH is maintained through a number of mechanisms, the most important of which are the respiratory system, the urinary system, and the body's buffer systems.
What direction does water move based on osmotic pressures?
The osmotic pressure gradient, or the difference between the osmotic pressures of two solutions, tends to result in water moving by osmosis toward the solution with the higher osmotic pressure
What are the primary functions of the ovaries?
The ovaries perform two main functions: They (1) produce ova and (2) secrete several hormones. Among these hormones are the estrogens, which include estradiol, estrone, and estriol, with estradiol being the most abundant. We will use the term estrogens to refer to all these hormones collectively. The ovaries also produce progesterone (proh-JES-ter-ohn), inhibin, and relaxin.
Acidosis is defined as a body fluid pH of less than 7.35 (note that acidemia refers to low blood pH specifically).
The pH of a patient with acidosis generally remains in the alkaline range (it is rare to see a pH less than 7.0), but it is still more acidic than the normal range. Acidosis develops when more hydrogen ions are added than the body's buffers can bind or when the number of buffers such as bicarbonate ions decreases. This causes neurons to become less excitable, leading to signs and symptoms of nervous system depression, such as slurred speech, drowsiness, and unresponsiveness. Left untreated, acidosis can lead to coma and, in severe cases, death.
Describe the three layers of the uterine wall. Label them in the image above.
The perimetrium (pehr-ee-MEE- tree-um) is the outermost serous layer and is an extension of the parietal peritoneum. The myometrium is the thick middle layer, composed of bundles of smooth muscle. It contracts rhythmically during orgasm and during childbirth to expel the fetus from the mother's body and in some women, to a lesser degree, during the menstrual cycle. The innermost endometrium lines the uterine cavity and is a mucous membrane composed of simple columnar epithelium on a layer of connective tissue called the lamina propria.
Phosphate Buffer System You don't have to memorize the chemical formulas for this buffer system. Know that it consists of a weak acid and a weak base and it a chemical buffer system important in cells and in the filtrate in the kidneys.
The phosphate buffer system consists of the weak acid dihydrogen phosphate (H2PO4−) and its conjugate base, hydrogen phosphate (HPO42−).
The kidneys remove hydrogen ions by the process of ______________ in the proximal tubule.
The proximal tubule cells secrete hydrogen ions from fixed acids by a secondary active transport process.
About how many primary oocytes are found in a newborn? About how many will reach maturity and ovulate? *****
The remaining 1-2 million oogonia begin to undergo meiosis I, at which point they are called primary oocytes. Of a woman's 300,000 primary oocytes, only about 400-500 will become mature secondary oocytes during her reproductive lifetime.
Why is there such a steep sodium ion gradient between cytosol and ECF?
The steep sodium ion gradient between the cytosol and ECF also makes this ion critical for all our electrophysiological processes. Recall that cells have a negative resting membrane potential—the inside of the cell is negative compared to the outside. When sodium ion channels open, the sodium ions follow their concentration gradient and rush into the cell. This causes the cell to gain positive charges and depolarize:
What is the stratum functionalis?
The stratum functionalis, or functional layer, undergoes cyclic changes in response to ovarian hormones. It detaches from the uterine wall and is shed as a discharge of roughly 35-50 ml of blood and other materials from the vagina approximately once per month during menstruation.
Metabolic acidosis is defined as the addition of hydrogen ions to the ECF (from acids other than carbon dioxide) or loss of bicarbonate ions.
The term refers to the fact that the condition can result from the addition of metabolic acids such as lactic acid, uric acid, and ketones to the blood. There are many different causes of metabolic acidosis, including prolonged diarrhea (which results in the loss of bicarbonate ions to the feces), the production of excess metabolic acids (such as occurs with diabetic ketoacidosis), failure of the kidneys to reabsorb bicarbonate ions or secrete hydrogen ions, and the ingestion of acidic drugs and toxins such as methanol.
What is the stratum basalis?
The thinner, deeper stratum basalis, or basal layer, does not thicken in response to ovarian hormones, but forms a new stratum functionalis after menstruation ends.
Phosphate ions levels are not regulated tightly. What two hormones regulate calcium and phosphate ion levels? What is the function of these hormones?
The two main hormones involved in calcium and phosphate ion regulation are parathyroid hormone (PTH) and vitamin D3 (calcitriol). -Recall that PTH is released from the parathyroid glands in response to a decrease in the calcium ion concentration of the blood, and it triggers osteoclast activity and calcium ion reabsorption in the kidneys (see Chapter 16). In addition, it decreases the reabsorption of phosphate ions. -Another important effect of PTH is the activation of vitamin D3, which is a potent stimulator of calcium ion absorption by the small intestine. Vitamin D3 also assists PTH in increasing osteoclast activity and calcium ion reabsorption from the kidneys. With regard to phosphate ions, vitamin D3 triggers their absorption from the small intestine. This increases the concentration of phosphate ions in the ECF, in contrast to the effects of PTH, which decreases their level. This helps to ensure that the level of phosphate ions in the ECF does not fall too low.
Do most women have a 28-day cycle? How does this vary?
However, fewer than 25% of women normally have 28-day cycles, and cycles as short as 21 days or as long as 40 days are relatively common. In addition, it is also common for the same woman to experience 1- or 2-day fluctuations from one cycle to the next.
When you drink water, what happens to the plasma volume? The blood hydrostatic pressure? The blood osmotic pressure?
However, if water is gained or lost from the plasma, its hydrostatic and osmotic pressures change. This in turn influences how much water leaves the plasma and enters the interstitial fluid, and so the hydrostatic and osmotic pressures of interstitial fluid also change. The differences in interstitial fluid pressures then directly influence the volume of the cytosol.
In what phase of meiosis is the secondary oocyte suspended? When would it complete meiosis?
However, it is then suspended in metaphase II and will not complete meiosis unless fertilization occurs.
What happens to most primordial follicles?
However, most of these follicles stop maturing and instead die by a process called atresia (ah-TREE-zee-ah), during which the oocyte first dies, followed by the collapse of the follicle. Indeed, by the time puberty is reached, the number of follicles has fallen by 50-90%.
What primary additional function does the female reproductive system have?
However, the female reproductive system must also support a developing conceptus—the offspring from fertilization through birth—and nourish an infant, and these functional differences lead to structural differences.
What is water toxicity?
However, this mechanism can fail when renal function is impaired, ADH is secreted abnormally, or extreme amounts of water are consumed in a short time period (a condition called water toxicity).
What happens with more severe hyperkalemia?
However, with severe hyperkalemia, the membrane can become so depolarized at rest that the cells are no longer excitable. In effect, this shuts down every excitable cell in the body, including neurons and muscle cells, and the result can be nearly instantaneous death.
Metabolic alkalosis results from a loss of hydrogen ions or an excess of bicarbonate ions.
Hydrogen ion loss is commonly the result of prolonged vomiting and the loss of acidic stomach contents. It may also be produced by certain diuretics or excess aldosterone, both of which lead to increased sodium ion reabsorption with concurrent hydrogen ion secretion. An increase in the bicarbonate ion level can happen when excessive bicarbonate salts have been ingested; the "culprit" is usually oral antacids taken for stomach ulcers or severe acid reflux. Compensation for metabolic alkalosis is both respiratory and renal. The respiratory response to a decreased hydrogen ion concentration is hypoventilation. This retains carbon dioxide and increases the number of hydrogen ions in the body. The renal response to metabolic alkalosis is the same as for respiratory alkalosis—the kidneys retain hydrogen ions and secrete bicarbonate ions into the urine.
What two hormones increase sodium ion retention in the kidneys? How do they work?
The two main hormones that increase sodium ion retention are angiotensin-II and aldosterone -A low extracellular sodium ion concentration is one of the major stimuli that triggers the RAAS. The low sodium ion concentration is detected by receptors in the macula densa of the nephron, which leads to the release of renin and the eventual formation of angiotensin-II. As we've covered, angiotensin-II increases the reabsorption of sodium ions from the proximal tubule. Angiotensin-II also stimulates aldosterone secretion, which causes sodium ion reabsorption from the distal tubule. Note that both actions also indirectly increase water reabsorption, as water follows sodium ions by osmosis.
What happens if a strong acid is added to a solution of pure water?
The upper left illustration in Figure 25.9a shows a strong acid, such as hydrochloric acid, being added to a beaker of water. Notice that the acid immediately donates its hydrogen ions to the solution, which increases its hydrogen ion concentration and therefore reduces its pH.
What is the uterine cycle? What is another term for this cycle?
The uterine cycle, or menstrual cycle, is the series of cyclic changes that the uterine endometrium goes through each month as it responds to the fluctuating levels of ovarian hormones. These uterine changes are coordinated with the levels of estrogen and progesterone released during the phases of the ovarian cycle, which are controlled by FSH and LH released from the anterior pituitary.
What are signs/symptoms of hypercalcemia?
Hypercalcemia affects other tissues, as well. Recall that calcium ions are responsible for the plateau phase of the cardiac action potential, which lengthens and strengthens the heart's contraction. When excess calcium ions are present, the plateau phase is shortened, making the contraction shorter and weaker. Hypercalcemia can cause decreased appetite and constipation due to decreased activity of gastrointestinal smooth muscle. It can also cause kidney stones, bone pain, and frequent urination.
What is hypercalcemia? What can cause hypercalcemia?
Hypercalcemia is defined as a plasma calcium ion concentration above 10.5 mg/dl. This condition is usually due to hyperparathyroidism but may also be caused by certain cancers, excess vitamin D, certain bone disorders, and renal failure.
What happens to cells in a hypertonic fluid?
Hypertonic ECF causes a cell to lose water. The ECF is hypertonic to the cytosol when it has a higher osmotic pressure than that of the cytosol and so has a greater ability to cause water movement by osmosis. So, a cell in a hypertonic ECF loses water because it leaves the cytosol and enters the ECF. This causes the cell to shrivel, or crenate.
How can hyponatremia be treated?
Hyponatremia due to overhydration is generally treated with hypertonic saline to restore the plasma sodium ion concentration and draw water back out of the cells.
What are the functions of the uterus? What is the common term for uterus?
The uterus (YOO-ter-uhs), known commonly as the womb, is part of the pathway through which sperm travel to reach the uterine tubes. It is also the site where a fertilized ovum implants, and it provides protection and nutritional support for a developing conceptus. In addition, contractions of the uterus are responsible for ejecting the fully developed conceptus (known as a fetus) during childbirth. When pregnancy does not occur, the uterus is the source of menstrual flow.
What occurs during orgasm in females? Do females have a refractory period?
The uterus does exhibit peristaltic waves of contraction, and the cervix pushes down somewhat into the vagina. If semen is present, these actions may draw semen farther into the reproductive tract, but female orgasm is not required for conception. Females do not experience a refractory period, so they may have multiple orgasms during a single sexual experience.
Describe the size and shape of the uterus.
The uterus is located in the pelvis anterior to the rectum and posterior to the urinary bladder. A hollow, thick-walled, muscular organ, it is similar in size and shape to an inverted pear. It weighs 30-40 g, but it is usually a little larger in women who have borne children.
What are the functions of the vagina?
The vagina (vuh-JY-nuh) is the female organ of copulation because it receives the penis (and semen) during sexual intercourse. It also provides a passageway for delivery of a fetus and for menstrual flow
Describe the size and location of the vagina.
The vagina is a thick-walled tube, approximately 8-10 cm (3.1-3.9 in.) long that extends from the cervix to the exterior of the body
What epithelium lines the adult vagina?
The vaginal mucosa is a stratified squamous epithelium, allowing it to withstand friction.
What is the term for the ridges in the wall of the vagina? Why is the pH kept low in the vagina?
The wall of the vagina is covered with transverse ridges, or rugae, which stimulate the penis during intercourse. The epithelial cells also secrete glycogen, which resident bacteria break down to produce ATP and lactic acid. This helps maintain the acidic pH that keeps the vagina healthy and free of infection. Earlier in the chapter, we mentioned that the acidic pH of the vagina is also hostile to sperm. This is one reason why the alkaline semen is so important for maintaining sperm health in the female reproductive tract.
What are sustentacular cells? What are some other names for these cells?
The yellow cells in Figure 26.7 that you can see surrounding the spermatogenic cells are supporting cells called sustentacular cells (sus′-ten-TAK-yoo-luhr), also referred to as nurse cells. These large cells extend from the basement membrane to the lumen of the tubule and are bound to one another by tight junctions.
What are some important functions of chloride ions?
Their high concentration in the ECF makes them an important osmotic particle, along with sodium ions. Chloride ions are also a critical component of some other processes, including the production of hydrochloric acid secreted by the stomach. In addition, chloride ions are involved in the secretion of newly formed bicarbonate ions from erythrocytes.
This is the most important chemical buffer system! You should know the chemical equation showing the conversion of carbon dioxide to bicarbonate ion!
There are three main chemical buffer systems in the body: the carbonic acid-bicarbonate ion buffer system, the phosphate buffer system, and the protein buffer system.
What is hyponatremia? What can cause hyponatremia?
Hyponatremia is defined as a plasma sodium ion concentration less than 135 mEq/l. Like hypernatremia, hyponatremia is often not related to the absolute number of sodium ions but, rather, is due to overhydration. One cause of hyponatremia with overhydration is hypersecretion of ADH, a condition known as syndrome of inappropriate ADH secretion -As with overhydration, hyponatremia can result in cellular swelling due to movement of water into the cytosol. It can also lead to problems with electrophysiology; specifically, it reduces the sodium ion gradient across the plasma membrane. This can slow depolarization, which slows the rate of action potential generation. Hyponatremia due to overhydration is generally treated with hypertonic saline to restore the plasma sodium ion concentration and draw water back out of the cells.
What happens to cells in a hypotonic fluid?
Hypotonic ECF causes a cell to gain water. The ECF is hypotonic to the cytosol when it has a lower osmotic pressure than the cytosol and so a lesser ability to cause water movement by osmosis. In this case, it's the cytosol that has a greater osmotic pressure, which gives it a greater ability to drive osmosis. For this reason, a cell in a hypotonic ECF gains water and will swell.
What is hyponatremia? What are the signs and symptoms of hyponatremia? How can overhydration/hyponatremia be treated?
Hypotonic hydration results in electrolyte imbalances due to dilution of the ECF. Particularly affected is the sodium ion concentration, which can fall dramatically, leading to hyponatremia. Together, the hyponatremia and cellular swelling can cause severe disturbances to homeostasis, particularly to the central nervous system. The swelling of neurons, or cerebral edema, affects their ability to function and can lead to mental status changes, seizures, coma, and even death. Treatment consists of administering hypertonic fluids to draw the water back out of the cell and into the interstitial fluid.
What can lead to identical twins?
Identical twins are a separate phenomenon that results from the fertilization of a single oocyte by a single sperm, followed by separation of the dividing cells in early development.
What hormone is released if fertilization takes place? What is a major impact of this?
If fertilization does take place, the outer layer of the developing conceptus begins to secrete the LH-like hormone human chorionic gonadotropin (hCG), which keeps the corpus luteum from degenerating and the progesterone level high. hCG is unique to the developing conceptus, which makes it useful as a target compound for home pregnancy tests.
What happens to the corpus luteum if a pregnancy does not occur?
If pregnancy does not occur, the corpus luteum begins to degenerate in approximately 10 days and stops producing hormones.
When there are water losses, what happens to the plasma volume? The blood hydrostatic pressure? The blood osmotic pressure?
In Figure 25.4b, we have the opposite situation of a water deficit due to dehydration. This has caused the hydrostatic pressure to decrease, leading to less water leaving the plasma, and it has also made the plasma hypertonic, meaning it now has a higher osmotic pressure. The hypertonic plasma will draw water out of the cytosol and interstitial fluid and into the plasma by osmosis. For this reason, the cell has shrunk.
What are some functions of sustentacular cells?
In addition to forming the blood testis barrier, sustentacular cells perform many other functions important to spermatogenesis, which explains why they are nicknamed nurse cells. These functions include the following: - providing structural support for spermatogonia development by maintaining the environment around the cells; - secreting substances that stimulate mitosis of spermatogonia and initiation of meiosis in response to testosterone and follicle-stimulating hormone; -providing nutrients to the dividing cells; -phagocytizing damaged spermatogenic cells and excess cytoplasm released from maturing spermatids; and -producing androgen-binding protein (ABP) and inhibin (see the next module), which help regulate spermatogenesis.
What happens at the arterial end of a capillary?
In most blood capillaries, the plasma has a high hydrostatic pressure at the capillary's arteriolar end—much higher than that of the interstitial fluid. This forces water out of the capillary and into the interstitial fluid.
What is the hymen?
In most women, the mucosa near the distal vaginal orifice forms an incomplete partition called the hymen. The hymen is very vascular and may bleed when it ruptures, which happens in about 50% of women during their first experience of sexual intercourse. However, it may also rupture from an injury or during activities such as sports
What happens to cells during dehydration?
In such cases, the water loss decreases the plasma volume, increasing its solute concentration and osmotic pressure. The changes in solute concentration lead to electrolyte imbalances in addition to water imbalances, which are covered in the next module.
Which phase of the cycle is less variable?
In these cases, the length of the follicular phase varies, but the luteal phase normally remains constant: It is 14 days from the time of ovulation to the end of the cycle.
Compare and contrast spermatogenesis and oogenesis.
-Both spermatogenesis and oogenesis produce haploid gametes with unique combinations of alleles. -One key distinction is the number of cells produced. -Another difference is in the structure of the gametes.
What is the most abundant intracellular cation? What is the most abundant extracellular cation?
-ICF: potassium -ECF: Sodium
What is a mammary gland? An areola? A nipple?
-Mammary gland: exocrine gland contained within a rounded skin-covered breast; consists of lobules with glandular alveoli that produces milk -Just below the center of each breast is an area of pigmented skin, the areola, which surrounds a central protruding nipple through which milk exits the gland.
What is female climacteric? What is menopause?
-The time from the onset of irregular menstrual cycles to their complete cessation, which may be up to 5 years in some women, is called the female climacteric. -menopause: the cessation of regular menstrual cycles that normally occurs between the ages of 45 and 55 years
List four hormones that ensure that regulate water balance. Which hormone is most important?
-We have discussed ADH and the other three hormones that affect fluid balance—angiotensin-II, aldosterone, and atrial natriuretic peptide (ANP) -ADH: a hormone produced by the hypothalamus and stored in the posterior pituitary that causes the insertion of aquaporin channels in the cells of the distal tubule and collecting system to allow water reabsorption
What assertions have been made by proponents of the alkaline diet? Is there any truth to these assertions?
-Well, according to proponents, we all have blood that is too acidic due to our diets, and acid, they say, causes inflammation, which causes disease. An alkaline diet is therefore the literal cure for every disease, up to and including cancer. As you might expect, these assertions are generally made by people trying to sell you something. -For the first claim, that dietary foods and liquids affect the pH of the blood, remember that the pH of stomach acid is extremely low—about 1-3—and this is true no matter what you eat. Also, remember that the pancreas secretes bicarbonate ions to neutralize the acidic stomach contents entering the duodenum. So, regardless of the alkalinity or acidity of your diet, the food you eat is going to leave your stomach at a pH of about 2, and travel through your small intestine at a pH of about 7. -Proponents do make one true claim, which is that an alkaline environment kills cancer cells. They're right: Cancer cells can't survive in a very alkaline environment, but neither can healthy cells. If the pH is high enough to kill cancer cells, all cells die.
Label the internal genitalia. Note that the image on the right is a superior view (looking down into the pelvis).
-ovaries, uterine tubes, uterus, vagina
Why is the steep concentration gradient of potassium ions critical to the function of neurons and muscle cells?
-potassium ions are the most abundant intracellular cation The concentration of potassium ions is higher in the cytosol of cells than in any other body fluids due primarily to the actions of the Na+/K+ pump. This steep concentration gradient, like that of sodium ions, is critical to the functioning of neurons and the three types of muscle cells in the body.
What is sensible water loss? Insensible water loss?
-sensible: a water loss that is "sensed" or noted; includes water lost to the urine and the feces -insensible: a water loss that is not "sensed" or noticed; includes water lost to sweat and ventilation
What are the three phases of the uterine cycle? When does each occur (given a 28-day cycle)?
1 Menstrual phase, days 1-5. 2 Proliferative (preovulatory) phase, days 6-14. 3 Secretory (postovulatory) phase, days 15-28
the stages of spermatogenesis in the seminiferous tubules
Before puberty, spermatogonia divide by mitosis, but only to produce more spermatogonia. When puberty begins, they become functional stem cells and divide, again by mitosis, to maintain the stem cell line and create more spermatogonia. However, some of the cells resulting from mitosis differentiate into diploid primary spermatocytes (sper-MAT-oh-sytz; step 1). As spermatogonia divide into these two cell types, the cell destined to become a primary spermatocyte is pushed toward the lumen of the seminiferous tubule while the spermatogonium takes its place along the basement membrane to replace its parent cell. The primary spermatocyte then undergoes meiosis I, forming two smaller, joined haploid cells called secondary spermatocytes (step 2). The two secondary spermatocytes rapidly undergo meiosis II and produce four small haploid spermatids (step 3). Notice in Figure 26.7 that the spermatids are located at the lumen of the tubule.
What forms the blood-testis barrier? Why is this barrier important?
Blood testis barrier: a barrier formed by sustentacular cells that prevents immune cells in the bloodstream from encountering the new antigens formed on the genetically unique sperm cells These tight junctions form a blood testis barrier that separates the forming sperm cells from the immune system. Immune cells in the bloodstream must be prevented from encountering the new antigens on the genetically unique sperm cells, as they would recognize these antigens as foreign and mount an immune response against them.
How does testosterone impact the following? Bones: Skeletal muscle: Erythropoiesis: Libido:
Bones: more calcium salts are deposited in bone, making it denser Skeletal muscle: mass increases, accounting for the higher muscle mass in males compared to females, and all organs are in general larger Erythropoiesis: causing males to have a higher number of erythrocytes than females Libido: it is the basis for the male libido, which is the desire for sexual activity. However, the long-held idea that testosterone is responsible for aggression is highly disputed, and much evidence suggests that it is not true.
Name some similarities between the male and female reproductive systems.
Both systems produce sex hormones and gametes, and both have a series of ducts to move the gametes.