Final exam Flashcards
What are the principal nitrogenous wastes produced in the body?
Urea; uric acid; creatinine.
- Where are the renal pyramids located?
Within the renal medulla.
- Compare and contrast the two limbs of the nephron loop (of Henle).
The descending limb is a thin segment containing simple squamous epithelium, which makes it very permeable to water. The ascending limb is a thick segment containing simple cuboidal epithelium and symporters that are involved in active transport of salts.
- Trace the flow of blood from an afferent arteriole until it drains into a venule.
Afferent arteriole to glomerular capillaries to efferent arteriole to peritubular capillaries/vasa recta to venule.
- How is the net filtration pressure established?
Net filtration pressure (NFP) is determined by glomerular blood hydrostatic pressure (GBHP) minus the sum of capsular hydrostatic pressure (CHP) and blood colloid osmotic pressure (BCOP).
- How would your kidneys respond to an increase in systemic blood pressure?
Signals to the smooth muscle fibers in the afferent arteriole will result in constriction of the afferent arteriole. This will reduce blood flow into the glomerular capillaries, causing a reduction in glomerular filtration.
- List two (2) effects of angiotensin II on the urinary system.
Constricts both afferent and efferent arterioles; stimulates adrenal cortex to release aldosterone to promote sodium retention and water reabsorption; stimulates pituitary gland to release ADH to make collecting ducts more permeable to water reabsorption.
- In which portion(s) of the nephron would sodium ions draw water back into the blood?
Proximal convoluted tublue and distal convoluted tubule.
- In which portion(s) of the nephron would sodium ions, potassium ions, and chloride ions be actively transported into the interstitial space?
Ascending limb of the nephron loop (of Henle).
- How would your body respond to elevated blood pressure caused by an increase in blood volume?
Heart would release atrial natriuretic peptide. ANP increases GFR and suppresses release of aldosterone and ADH.
- What will happen to urine production if ADH secretion is blocked? EXPLAIN.
Urine production will increase. Without ADH, aquaporins cannot be inserted into the collecting ducts. They become less permeable to water reabsorption from the urine.
- What is the countercurrent multiplier?
A mechanism established by the nephron loop (of Henle) that creates an osmotic gradient in the interstitial fluid of the renal medulla that will help the collecting ducts reabsorb water from the urine, provided ADH is present.
- Why would a strict vegetarian tend to produce alkaline urine?
Vegetarians consume very little, if any, animal protein. Thus, they don’t have to process the amino acids that would contribute hydrogen ions to the blood. The kidneys wouldn’t have to excrete as many hydrogen ions in the urine, so urine is alkaline.
- Why does drinking beer make you have to urinate?
Beer contains ethyl alcohol, which is a diuretic. Alcohol inhibits the release of ADH. Therefore, the collecting ducts are less permeable to water reabsorption and more urine is produced.
- Explain the process of micturition.
As the urinary bladder fills with urine, stretch receptors in its wall send signals to the spinal cord and to a micturition center in the pons. Spinal cord sends parasympathetic motor signals back to the bladder to stimulate the detrusor muscle to contract and the internal urethral sphincter to relax. Signals are also sent to the cerebral cortex that would allow voluntary relaxation of the external urethral sphincter. The bladder can now be emptied.
- Why are females more prone to bladder infections than males?
Female anatomy. The female external urethral orifice is located close to the anus. E. coli bacteria can spread to the urethral opening and migrate up the short female urethra to the urinary bladder causing cystitis.
- Compare and contrast hypovolemia and dehydration.
Both are examples of fluid deficiency in the body. Hypovolemia occurs when both water and sodium are eliminated without adequate replacement and total body water is reduced. Dehydration occurs if the body eliminates more water than sodium, creating osmolarity imbalances.
- Why would hypernatremia lead to hypertension?
Too much sodium is going to promote the retention of water from tubular fluid into the blood. Increasing the blood volume will increase blood pressure.
- How would the respiratory system respond to lower blood pH?
Hyperventilation. By removing carbon dioxide more rapidly, hydrogen ions will bind with bicarbonate ions to replace the carbon dioxide and pH will rise to normal levels.
- How would the kidneys respond to metabolic acidosis?
Kidneys will remove excess hydrogen ions from the blood and excrete them in the urine.
The kidneys control blood composition and volume by
removing wastes and regulating water levels.
Kidneys regulate osmolarity of body fluids by
controlling solutes and water levels.
kidneys regulate blood pH
by excreting hydrogen ions
kidneys regulate BP by
activating renin-angiotensin pathway
kidneys control oxygen-carrying capacity of blood
by secreting erythropoietin
kidneys contribute to metabolism by
synthesizing glucose during periods of starvation
nitrogenous wastes
metabolic wastes that result from breakdown of proteins
how does ammonia form
amino groups removed from amino acids combine with hydrogen ions
ammonia gets converted into
less toxic urea by the liver which uses less water
the breakdown of nucleic acids forms
uric acid
creatinine results from
use of creatine phosphate during muscle metabolism
amount of nitrogenous waste in blood is
blood urea nitrogen (BUN) with levels at 10-20 mg/ml
elevated BUN
azotemia which indicates renal insufficiency
elevated BUN leads to
uremia, which causes diarrhea, vomiting, dyspnea, cardiac arrhythmia, convulsions, coma, death
sudoriferous glands in skin eliminate excess
heat and excrete water, with small amounts of urea
kidneys extend from what parts of the spine
T-12 to L-3
how much does an adult kidney weigh
about 150 grams. right is slightly lower than left
which surface of the kidney is convex
lateral surface
fatty adipose capsule cushions kidney
from trauma and holds it in place
fibrous renal fascia anchors
kidney to abdominal wall
renal parenchyma
glandular tissue that forms urine
minor calyx collects
urine. two or three together then transport it to major calyx
each kidney contains over 1 million
nephrons that carry out kidney functions
descending limb of henle
permeable to water
ascending limb of henle
involved in salt transport
collecting duct
transfers urine into papillary duct
glomerular filtrate
water and substances that are dissolved in blood plasma are forced out of glomerular capillaries and into glomerular capsule
Endothelial cells in glomerular capillaries join po
docytes to form
a filtration membrane that filters
water and small solutes, but not plasma proteins or
formed elements
glomerular endothelial cells have large fenestratio
which solutes pass through
pedicels
are foot-like extensions from podocytes that wrap around glomerular capillaries to form filtration slits that block negative ions
proteinuria(excess protein) and hematuria(RBCs in urine)
Kidney infection or kidney trauma can damage the fi
ltration membrane and allow plasma proteins
and/or formed elements to enter the filtrate
Glomerular blood hydrostatic pressure (GBHP) is the
main force responsible for moving water and
solutes out of blood plasma through the filtration
membrane.
Capsular hydrostatic pressure (CHP) opposes
additio
nal filtration because there is a high rate of
filtration and because fluid is already present in
the renal tubule.
Blood colloid osmotic pressure (BCOP) also opposes
filtration
because of the plasma proteins that
are present in blood plasma.
Net filtration pressure promotes filtration
OUT of the glomerular capillaries
The glomerular filtration rate (GFR) refers to
the amount of filtrate that is formed per minute in all of the renal corpuscles of both kidneys.
GFR for males and females
125 mL/mn for men, produces 180L of filtrate and 105 for women produces 150L of filtrate
GFR is directly proportional to
NFP, so changes in GBHP, CHP, or BCOP will affect GFR
if the GFR is too high, filtrate will flow through
renal tubules too quickly for them to reabsorb water and solutes.urinary output rises and creates a risk for becoming dehydrated
If the GFR is too low, filtrate will flow through
renal tubules too slowly and wastes will get reabsorbed. creates a risk for developing azotemia
Renal autoregulation describes the ability of the kidneys to maintain constant
renal blood flow and glomerular filtration despite changes in arterial blood pressure
myogenic mechanism occurs when
when arterial blood pressure changes affects smooth muscle in walls of afferent arterioles.
when blood pressure rises
smooth muscle fibers contract and constrict afferent arteriole which decreases blood flow into glomerulus to reduce GFR
glomerular filtrate is only 3% what
filtrate
when blood pressure drops, smooth muscle fibers
relax and dilate afferent arteriole which increases blood flow into glomerulus to raise GFR
tubuloglomerular feedback involves
juxtaglomerular apparatus
when GFR is elevated, filtrate
flows through renal tubule too fast
when GFR falls, flow of blood
from afferent arteriole into glomerulus is increased
macula densa cells release vasoconstrictor that reduces
flow of blood from afferent arteriole into glomerulus to reduce GFR
autoregulation does not completely block changes in
GFR, allows for fluctuation within narrow limits
autoregulation cannot compensate for extreme variations in
BP, but it will prevent large changes in water and solute excretion
Neural regulation uses sympathetic nerve fibers to
send signals to
afferent arterioles that constrict them and decrease the flow of blood into the glomerular capillaries in order to reduce GFR and maintain systemic blood pressure
when is neural regulation most likely to occur
during extreme stress or emergency situations
The renin-angiotensin mechanism is activated by
a drop in BP
juxtaglomerular cells secrete renin which triggers
conversion of angiotensinogen to angiotensinogen II
angiotensin II constricts both afferent and efferent arteriole to reduce
GFR
angiotensin II stimulates adrenal cortex to secrete aldosterone
to promote water and sodium retention
angiotensin II stimulates pituitary gland to secrete ADH
to increase water absorption
Tubular reabsorption returns
filtered water and filtered solutes back to the bloodstream
interstitial fluid pressure helps
drive water back into peritubular capillaries
blood hydrostatic pressure is relatively low in the
peritubular capillaries which reduces resistance to reabsorption
plasma proteins are not filtered which raises
blood colloid osmotic pressure in peritubular capillaries
total plasma volume filters through the renal tubules every
22 minutes, draining all in 30
transcellular route allows substances to pass from
filtrate across epithelial cells of tubule into interstial fluid
paracellular route allows substances to
“leak” out of filtrate through “tight” junctions between epithelial cells.
Substances that get reabsorbed from the filtrate are
taken into the peritubular capillaries
blood retains its plasma proteins, so water gets
drawn into capillaries by osmosis
solvent drag occurs when
dissolved solutes enter capillaries by following water
primary active transport uses ATP energy to
pump substances into capillaries
secondary active transport uses energy
from ionic electrochemical gradient to pump substances into the capillaries
symporters can move two or more substances
across a membrane in same direction
antiporters can move two or more substances
across a membrane in opposite directions
most significant transport substance our of filtrate
glucose which has highest tmax
Transport maximum (T max) describes the reabsorption limit of a
renal tubule due to the number of
transport proteins that are available.
each particular solute has its own Tmax when
all its transporters are occupied
tubular secretion removes substances from
the peritubular capillaries and adds them to the filtrate. puts wastes into urine
Most tubular reabsorption occurs in the
proximal convoluted tubule.
Sodium reabsorption creates
an osmotic gradient and an electrical gradient to drive the reabsorption of water and other solutes.
sodium ions are reabsorbed by
symporters and antiporters.
sodium is driving force behind reabsorption
of stuff in PCT
80% of all active transport is used to reabsorb
sodium ions which are most abundant cations
Chloride ions get reabsorbed because
they follow sodium ions due to electrical attraction
water reabsorption raises chloride concentration in
tubular fluid and creates a chloride gradient
Bicarbonate ions seem to be reabsorbed from
the filtrate, but they really aren’t
urine is usually free of bicarbonate ions
because they don’t cross membrane of PCT
bicarbonate ions combine with hydrogen ions present
in tubular fluid to form
carbonic acid which dissolves into water and CO2
carbon dioxide enters tubule cells and combines with
water to again form carbonic acid which dissociates into bicarbonate and hydrogen ions
bicarbonate ions are pumped into
blood
hydrogen ions are pumped back into
tubular fluid
Glucose is co-transported with
sodium ions because glucose isnt absorbed fast enough by symporters
Nitrogenous wastes are reabsorbed int
the capillaries.
40% to 60% of urea formed gets reabsorbe
along with water and all uric acid but no creatinine
obligatory water reabsorption
Water gets reabsorbed into the peritubular capillaries/takes place in PCT
about 2/3 of this water is reabsorbed through
aquaporins also in PCT
reabsorption of sodium ions and chloride ions and other solutes makes tissue fluid
hypertonic to tubular fluid
osmolarity of tubular fluid remains
constant
Tubular secretion in the PCT extracts
urea, uric acid, ammonia, and other wastes from the blood and transfers them into the tubular fluid
bicarbonate ions and hydrogen ions are secreted into
tubular fluid to regulate pH of body fluid
The primary function of the nephron loop (of Henle) is to create
a gradient for urine concentration and water conservation
tubular fluid in the nephron loop is quite different from glomerular filtrate and blood plasma
because glucose and other solutes have been reabsorbed
The descending limb of the nephron loop will reabsorb
about 15% of the water present in the glomerular filtrate
The thick ascending limb of the nephron loop has symporters that will reabsorb
one sodium ion, one potassium ion, and two chloride ions from the tubular fluid/ limb is impermeable to water
Principal cells in the collecting duct reabsorb
reabsorb sodium ions and secrete potassium ions.
Intercalated cells in the collecting duct reabsorb
potassium ions and bicarbonate ions, but secrete hydrogen ions
“proton pumps” are effective
at secreting hydrogen ions
Aldosterone is secreted by the adrenal cortex when
blood levels of sodium fall or when blood levels
of potassium rise, causing the DCT and the collecting duct to reabsorb more sodium ions and secrete more potassium ions.
aldosterone targets principal cells, causing them to
open so very little sodium leaves in urine
urine can be 1000 times more
acidic than blood thereby maintaining pH of body fluids
The increase in blood pressure that results from increased blood volume triggers the release of
of atrial natriuretic peptide from the heart
chloride ions and water follow sodium ions which
reduces urine volume, salt balance is maintained
atrial natriuretic peptide does what
increases glomerular filtration rate, suppresses release of ADH by pituitary gland, suppresses release of aldosterone by counteracting effects of angiotensin II, inhibits reabsorption of sodium ions
Antidiuretic hormone makes the collecting ducts more permeable to
water, thereby increasing the reabsorption of water into the tissue fluid and the bloodstream
ADH inserts aquaporins into
membranes of principal cells in collecting ducts
Despite daily fluctuations in fluid intake, total fluid volume in one’s body remains
stable
the osmolarity of the tubular fluid increases as it flows
down the descending limb of nephron loop, then decreases as it flows up the ascending limb of the nephron loop, and decreases even more as it flows through the DCT and the collecting duct
Urine can be as much as four times more dilute than
blood plasma or glomerular filtrate
principal cells in collecting ducts are impermeable to water when
ADH levels are low
When water intake is low or when water loss is high the kidneys produce
small volumes of highly concentrated urine because ADH has a strong influence on the collecting ducts
osmolarity of interstitial fluid increases four-fold from
renal cortex to renal medulla
medullary portion of collecting duct is more permeable to
water than to NaCl
Concentrated urine is formed because the
nephron loop creates a countercurrent multiplier to
maintain an osmotic gradient in the interstitial fluid of the renal medulla.
A countercurrent exchange system develops from the
arrangement of
juxtamedullary nephrons and the vasa recta
as blood flows into medulla, water diffuses out of
the
vasa recta and sodium and chloride ions diffuse into vasa recta
as blood flows out of the medulla, sodium ions and
chloride ions diffuse out of
vasa recta, and water diffuses into vasa recta
net result is reabsorption of
water from tubular fluid. blood at end of vasa recta is greater than at beginning
The overall effect is that ADH makes the collecting
ducts more permeable to
water by inserting aquaporins into the membranes of the principal cells, and the osmotic gradient in the renal medulla “pulls” water out of the collecting ducts to form concentrated urine.
Urinalysis
examines the physical, chemical, and microscopic properties of urine
yellow color of urine is due to
urochrome pigment produced during breakdown of hemoglobin
Urine is typically clear, but it will turn cloudy as a consequence of
bacterial growth or from pus formation caused by a urinary tract infection
bacteria change urea to
ammonia
what do people form after eating asparagus
methylmercaptan
what do diabetics produce in their urine
ketone bodies
what do people produce in their urine that smells like a mouse cage
phenylketonuria
The pH of urine
ranges from 4.5 to 8.2, but it is usually slightly acidic
increase acidity of urine
high protein diets
decrease acidity of urine
vegetarian diets
Urine has a higher specific gravity than
water, depending on its solute concentration
Normal urine output is between
1 and 2 liters per day.
polyuria
describes excessive production of urine
oligouria
describes scanty output of urine
anuria
refers to an output of less than 100 mL per day
Diabetes is one of several metabolic disorders characterized by
polyuria
excess glucose in tubular fluid blocks reabsorption
of
water and leads to dehydration
diabetes mellitus and gestational diabetes result
from
hyperglycemia and can be diagnosed from glycosuria
hyposecretion of ADH prevents the collecting ducts
from reabsorbing water, causing
diabetes insipidus to develop
Diuretics are substances that increase
urine volume by increasing glomerular filtration and/or reducing tubular reabsorption
caffeine dilates
afferent arterioles which increases GFR
alcohol inhibits
ADH secretion reduces tubular reabsorption of water
Lasix inhibits
sodium reabsorption from nephron loop reduces reabsorption of water from collecting ducts
Renal clearance measures the volume of
blood that is cleared of a particular substance and it is expressed in mL/min.
solute clearance depends on
glomerular filtration, tubular reabsorption, secretion
a blood sample and a urine sample are collected, and concentration of urea in each is measured and compared to
rate of urine output
renal clearance is important during drug therapy cause
it allows drug dosage to be set to maintain therapeutic levels of that drug
The glomerular filtration rate can be assessed by measuring the rate of
urine output and the concentration of a solute that completely remains in the tubular fluid and gets cleared in the urine
inulin is completely filtered by
glomerulus and added to urine. renal clearance is equal to GFR
clearance value less than that of inulin means
substance has been reabsorbed
clearance value greater than that of inulin means
substance has been secreted into tubular fluid
ureter
is 25 cm long and transports urine from the renal pelvis to the urinary bladder
arrangement of ureters at back of bladder prevents
backflow of urine as bladder fills
adventitia is
connective tissue that anchors ureters to surrounding tissues
muscularis is
composed of two layers of smooth muscle
contractions initiate
peristalsis to move urine through ureter toward bladder
mucosa has
transitional epithelium and underlying lamina propria
urinary bladder
hollow muscular organ on the floor of the pelvic cavity
trigone is a small triangular area in
the floor of the bladder
fibrous adventitia
continuous with adventitia of ureters
detrusor muscle
consists of three layers of smooth muscle that form internal urethral sphincter
mucosa of urinary bladder has
transitional epithelium. when bladder is relaxed, mucosa exhibits conspicuous rugae
The bladder is highly distensible and typically holds
500 mL of urine, but it can hold up to 800 mL
female urethra is
3-4 cm
male urethra
15-20 cm
membranous urethra passes through
urogenital diaphragm
Micturition (urination; voiding) empties
urinary bladder and is controlled by a spinal micturition reflex
for micturition to occur, detrusor muscle must
contract, internal urethral sphincter must relax,external urethral sphincter must open
stretch receptors in the wall of the urinary bladder
send nerve impulses to the sacral portion of the spinal cord when the bladder reaches
200-400 mL
Parasympathetic motor impulses from the spinal cord
stimulate
the detrusor muscle to contract and the internal urethral sphincter to relax
Urinary retention
prevents the urinary bladder from emptying its contents/ often a consequence of general anesthesia
A urinary tract infection (UTI)
describes an infection in any part of the urinary system, or the presence of bacteria that may produce blood or pus in the urine
symptoms of UTI
painful and/or burning urination,
urgent and/or frequent urination, low-back
pain, bed-wetting/ may also be asymptomat
Urethritis
is an inflammation of the urethra that can cause painful urination
Cystitis
is an inflammation of the urinary bladder, usually in the trigone, which is often accompanied by hematuria.
females are more prone to cystitis because
E. coli bacteria from the anus can easily spread up
short urethra into bladder/ if untreated, bacteria may spread to renal pelvis, renal cortex, and nephrons and cause pyelonephritis
Glomerulonephritis
is an inflammation of the glomeruli that makes them swollen and more permeable, which leads to hematuria and proteinuria and even renal failure/ may be autoimmune
polycystic kidney disease
renal tubules riddled with cysts can cause renal failure
Renal calculi
when excess calcium intake or insufficient water intake cause calcium or phosphates or uric acid to crystallize into insoluble stones
common causes of renal calculi
oxalic acid from beets, colas, leafy green vegetables, and tea is a common cause
stones from renal calculi may block
ureters and create excruciating pain as they pass through ureter
treatment for kidney stones may involve
stone-dissolving drugs or surgery or ultrasound lithotripsy
Chronic renal disease
if one’s GFR is below 60 mL/min for at least 3 months.
what happens during chronic renal disease
production of glomerular filtrate declines, concentration of nitrogenous wastes increases, and
the pH of the blood becomes more acidic
leading cause of chronic renal disease
diabetes, followed by hypertension
Renal failure
occurs if one’s GFR falls below 15 mL/min and must be treated with dialysis or a kidney transplant.
Approximately 55 to 60% of our total body weight is
due to fluids. what is male and females %
male-60% female-50%
About two-thirds of the water in the body is
intracellular fluid (ICF).
The remaining one-third of the water in the body is
extracellular fluid (ECF), which is distributed among interstitial fluid, blood plasma, lymph, and trans-cellular fluid.
fluid gain is primarily due to
preformed water from ingested foods/liquids and metabolic wastes from chemical reactions in cells
fluid loss comes from
obligatory water loss
insensible water loss comes from
expired breath, perspiration, cutaneous transpiration, and defecation
sensible water loss
comes from urine
Water intake is controlled by a
hypothalamic “thirst center” that responds to dehydration.
falling blood pressure will trigger release of
angiotensin II
rising blood osmolarity will trigger release of
ADH
increasing osmolarity of ECF will be detected by
osmoreceptors
Water output is controlled by
variations in urine volume usually linked to sodium reabsorption
kidneys begin to eliminate water within
30 minutes of ingestion
Fluid deficiency occurs when
water output exceeds water input over a long period of time.
Hypovolemia
when the body eliminates water and sodium without adequately replacing them
hypovolemia can be caused by
hemorrhage, severe burns, chronic vomiting, or chronic diarrhea, cold weather
• blood vessels constrict in order to conserve heat
• cold, dry air increases water loss during respiration
Dehydration occurs when
the body eliminates more water than sodium/caused by diabetes mellitus, diabetes insipidus, profuse sweating, or overuse of diuretics
Water intoxication occurs if the body replaces
water without replacing sodium/ECF becomes hypotonic and water moves into tissue cells causes them to swell
Fluid sequestration(edema) occurs if
excess fluid accumulates in interstitial space
Electrolytes are physiologically important in order
for the body to maintain
homeostasis
Electrolytes help to
chemically reactive participants in metabolic pathways,
help to determine electrical potential across cell
membranes, control osmolarity of body fluids and water content and distribution
Blood plasma is the usual reference point for measuring
electrolyte concentration
Sodium is the only electrolyte to exert significant
osmotic pressure and it is essential for transmitting
action potentials, for buffering the blood, and for creating the osmotic pressure
how many grams of sodium per day does an adult need
.5 grams but typically ingest 3-7
estrogens can mimic effect of
aldosterone causing females to retain sodium ions and water during menstrual cycle and pregnancy
hyponatremia
excessive water intake or decrease in sodium intake. consequences include muscle weakness, dizziness, headache, hypotension, tachycardia
hypernatremia
due to dehydration or excessive sodium intake/consequences include intense thirst, hypertension, edema, convulsions
Potassium ions are the most abundant
intracellular cations and potassium balance is maintained by the kidneys
Sodium ions are the most abundant
extracellular cations
Potassium helps establish
resting membrane potentials and action potentials, intracellular osmolarity and cell volume
aldosterone is principal regulator of
potassium levels/ when aldosterone stimulates reabsorption of sodium ions, it promotes secretion of
potassium ions
hypokalemia
can be caused by heavy sweating, chronic vomiting, chronic diarrhea, or laxative abuse/ consequences include muscle fatigue, loss of muscle tone, mental confusion, irregular heart activity
hyperkalemia can be caused by
injuries that crush tissues, renal failure, aldosterone deficiency/ consequences include irritability, nausea, vomiting muscle weakness; death can occur if heart rate gets increased too much
Calcium is the most abundant
mineral in the body, but calcium ion concentration is kept low in cells.
Calcium is stored in
bone tissue/ parathyroid hormone and calcitriol regulate blood levels of calcium
hypocalcemia
can be caused by increased calcium loss, vitamin D deficiency, thyroid and/or parathyroid gland problems/ consequences include numbness and tingling, muscle
cramps, convulsions, bone fractures
hypercalcemia
caused by thyroid gland problems, parathyroid gland problems, over use of vitamin D/ consequences include lethargy, muscle weakness, cardiac arrhythmia, and mental disorientation
Chloride ions are the major
extracellular anions/ involved in regulating osmolarity between fluid compartments, forming stomach acid, loading and unloading carbon dioxide
Phosphate ions are highly concentrated in
intracellular fluid./ participate in metabolic pathways and act as buffers that help to maintain pH of body fluids
parathyroid hormone regulates what ion levels
phosphate
Hydrogen ion concentration must be controlled to maintain
blood pH between 7.35 and 7.45,
Buffers are salts of weak acids or salts of weak bases that resist changes in
pH when strong acids or strong bases, respectively, are added to the blood
physiological buffers stabilize
pH by controlling output of acids or bases or carbon dioxide
chemical buffers bind
hydrogen ions and remove them from solution when concentration rise can restore pH within seconds but amount that can be buffered depends on concentration and pH of environment
urinary system buffers greatest amount of
acid or base but requires several hours or days to exert max efforts
The bicarbonate buffer system is a solution of
carbonic acid and bicarbonate ions that serves as the principal buffer in the extracellular fluid.
bicarbonate buffer system equation
CO2+ H2O H2CO3 HCO3-1+ H+1 reaction can go in either direction
when carbonic acid dissociates, it releases
hydrogen ions to lower pH
bicarbonate ions bind hydrogen ions and remove them
to
raise pH
lungs and kidneys constantly remove carbon dioxide
to prevent
equilibrium
The phosphate buffer system is a solution of
dihydrogen phosphate ion and monohydrogen
phosphate ion that can release hydrogen ions in order to lower pH, or bind hydrogen ions in order to raise pH in the urine and/or intracellular fluid
what is a stronger buffering system than bicarbonate buffer system
phosphate buffer system
phosphate buffers are very effective in
urine and ICF where phosphate ions are high
The protein buffer system has the most abundant buffers in the
ECF and blood plasma, using hemoglobin to accomplish its goals
amino acid side groups can release
hydrogen ions to lower pH
The equation for the bicarbonate buffer system indicates the
impact that CO2 has on pH
respiratory system can neutralize two to three times more
acid than chemical buffers/pH can be restored within minutes
hypercapnia stimulates
deep and rapid breathing to eliminate more carbon dioxide and shift the reaction to the left
Kidneys neutralize more acid or base than the respiratory system or chemical buffers, because
the renal tubules secrete hydrogen ions into the tubular fluid rather than binding hydrogen ions to other
chemicals
kidneys neutralize as long as
there is a hydrogen ion gradient between tubule cells and tubular fluid and pH is higher than 4.5
for kidneys to reabsorb bicarbonate ions, they must secrete
hydrogen ion
hydrogen ion secretion occurs in
PCT and in intercalated cells of collecting ducts
Acidosis occurs when blood pH falls below
7.35
what does acidosis do
can suppress central nervous system and cause confusion, disorientation or coma
respiratory acidosis results from inability of respiratory system to
eliminate carbon dioxide
metabolic acidosis results from
excessive production of hydrogen ions, lactic acid fermentation, ketone bodies produced by alcoholism or diabetes mellitus, overuse of aspirin or laxative
alkalosis occurs when blood pH rises above
7.45
alkalosis can
hyperexcite neuromuscular system, shifts membrane potential closer to threshold / causes muscular spasms or cunvulsions
respiratory alkalosis results from
hyperventilation
metabolic alkalosis results from
rapid elimination of hydrogen ions during vomiting
increase in hydrogen ions in nerve cells requires
removal of
potassium ions so RMP becomes hyper polarized
The genetic sex of an individual is determined at the time of fertilization by
by the sex chromosome that is carried by the sperm
there is no morphological indication of sex until
week six or seven of embryonic development
embryo can be described as
sexually bipotential or potentially bisexual
The gonads develop from
embryonic tissue called mesoderm
each gonad is enclosed by
germinal epithelium
approximately 43 days after fertilization what begins
Y chromosome begins to affect indifferent gonads
carries a sex-determining gene
Y-chromosome
genital ducts
2 pairs are present during the indifferent stage
mesonephros consists of
of mesonephric tubules and mesonephric ducts
causes mesonephros to differentiate into male reproductive tract
testosterone
paramesonephros consists of
a pair of Muellerian ducts
causes paamesonephros to degenerate
presence of Muellerian-inhibiting factor
The scrotum hangs from
the lower abdomen behind the base of the penis.
Sex determining region produces
testis-determining factor (TDF) which directs development of different gonads into testes
what tissues does the scrotum consist of
consists of loose skin, superficial fascia, and muscle tissue
dartos is a
sheath of smooth muscle fibers located beneath the skin
cremaster muscles
are thin strands of skeletal muscle that suspend the testes
what do the walls of the scrotum contain
numerous sweat glands
A medial septum divides the scrotum into
two compartments, each containing one testis./location of septum can be seen externally as median raphe
The location of the scrotum outside of the body cavity permits
thermoregulation of the testes to
enhance the production and survival of sperm
dartos and cremaster muscles will contract in response to
cold temps, draws closer to body
pampiniform plexus
blood vessels that supply testes with blood
scrotal temp ideal for sperm
35 degrees Celsius
male gonads
testes
cytogenic
testes are because they produce sperm
function as endocrine glands because they produce testosterone
testes
There are two oval testes and each is about how long
4 cm long and 15 grams
tunica vaginalis lines
scrotum
tunica albuginea divides its testis into
200-300 lobules
Each lobule contains several highly coiled
seminiferous tubules
how long is each seminiferous tubule
80 cm
Sertoli cells
in the walls of seminiferous tubules/they protect and nourish developing sperm cell, destroy damaged or defective sperm cells,
interstitial cells (of Leydig)
fill the spaces between the seminiferous tubules/produce and secrete testosterone
primary sex cords
Finger-like strands of the germinal epithelium that grow into an indifferent gonad and carry primordial germ cells inward
form a blood-testis barrier
sertoli cells/ to prevent sperm from entering blood stream where their membrane antigens could trigger immune response.
in a male the medulla expands and forms
bulk of testis, while cortex condenses and forms tunica albuginea
in a male the primary sex cords
lose contact with germinal epithelium as it disappears then become hollow and start to form seminiferous tubules
in a male cells that remain in walls of seminiferous tubules become
Sertoli cells
in a male primordial germ cells within primary sex cords become
spermatogonia
The testes will descend through an opening in the
inguinal canal into the scrotum sometime during the seventh month of fetal development.
cryptorchidism
failure of testes to descend/ can cause sterility
risk for testicular cancer is how many times greater if boys have cryptorchidism
30 to 50 times
in about 80% of cases of cryptorchidism testes will
descend within a year
Immature sperm will move from the seminiferous tubules into the
rete testis, which is a network of
about 100 short tubes that drain the seminiferous tubules into a collection of short efferent ductules
The efferent ductules converge to form a highly coiled, comma-shaped
epididymis along the superior/dorsal margin of the testis
immature sperm cells mature and become motile over
a period of
10-14 days as they pass through epididymis
how long can sperm stay in epididymis
a month before they disintegrate and get reabsorbed
Mature sperm move from the epididymis into the
ductus (vas) deferens
vas deferens joins together with what to form the spermatic cord
blood vessels, lymphatic vessels, nerves, and cremaster
muscle
behind urinary bladder, distal end of the vas defer
ens expands and forms
ampulla for temporary sperm storage
The ampulla of the ductus (vas) deferens merges with a
a duct from the seminal vesicle to form an
ejaculatory duct behind the urinary bladder
ejaculatory duct transports
sperm into urethra
male urethra is
15 to 20 cm long and serves as a common passage for sperm and urine
prostatic urethra extends from
urinary bladder through prostate gland
membranous urethra passes through
urogenital diaphragm
spongy (penile) urethra passes through
spongy tissue of penis
When the interstitial cells (of Leydig) start to produce testosterone, the
mesonephric tubules and the mesonephric ducts begin to differentiate
mesonephric tubules merge with primary sex cords to
form
efferent ductules
ductus (vas) deferens forms from middle portion of
mesonephric duct
distal portion of mesonephric duct expands laterally to form
seminal vesicle
male accessory glands
produce and secrete the liquid
portion of semen
semen is a mixture of
sperm, nutrient-rich mucus, proteins, and enzymes
Seminal vesicles are
pouch-like sacs at base of the bladder and they contribute about 60% of the volume of semen.
energy source for sperm
fructose,citric acid
proseminogelin
protein that gets converted into seminogelin causes semen to form clot in vagina
prostate gland
doughnut-shaped gland that surrounds the urethra as it exits the bladder and it also contributes to the volume of semen
prostaglandins may cause mucus in the cervical canal to become
thinner, making it easier for sperm to travel from vagina to uterus/ may stimulate smooth muscle contractions
acid phosphatase
helps semen form clot in vagina
bicarbonate buffers neutralize natural acidity in
vagina
fibrinolysin
decoagulates a semen clot after vaginal acidity has been neutralized
serine protease
enzyme that breaks down proteins
bulbourethral (Cowper’s) glands
mall spherical structures located beneath the prostate
gland on either side of the membranous urethra
secrete alkaline substances to neutralize acidic re
residue left by urine in urethra and mucus to lubricate penis
bulbourethral glands
male copulatory organ.
penis
The shaft of the penis contain
three cylindrical masses of erectile tissue, each of which is surrounded by fibrous tissue
two corpora cavernosa penis are
dorsolateral masses and each contains an artery that dilates to produce erection
corpus spongiosum penis is a
ventral mass that contains spongy urethra
glans penis
richly innervated with sensory nerve endings and covered with a loose skin fold
small glands beneath the foreskin secrete
waxy smegma
genital tubercle appears early during
embryonic development
labioscrotal swellings begin to develop
lateral to urethral folds
glans develops at the end of the
genital tubercle
lateral buttresses form on either side of
phallus
Testosterone triggers the
genital tubercle to differentiate by the 10th week following fertilization and the external genitalia start to appear distinctly male.
urethral folds fuse on the
ventral surface of the phallus to form a hollow tube that will eventually become the penile urethra.
lateral buttresses fold over to form most of the
shaft of the penis, and the glans penis expands from the glans at the end of the phallus
labioscrotal swellings will fuse and form the
scrotum
urethral groove elongates in both directions; one end breaks through the glans to form the
external urethral orifice and the opposite end grows inward to form the bladder.
one pair of outgrowths off urethral groove fuse to
become
prostate gland
male puberty typically begins at age
10 or 11
adrenal glands produce and release
low levels of testosterone before puberty begins.
creates feedback inhibition
With the onset of puberty, inhibition stops so
hypothalamus can release GnRH
GnRH triggers
anterior lobe of pituitary gland to produce and release two gonadotropins
Follicle stimulating hormone (FSH) initiates
sperm production
Interstitial cell stimulating hormone (ICSH) stimulates the
interstitial cells (of Leydig) to synthesize and release testosterone
Testosterone produces multiple effects on a boy’s body.including
stimulates spermatogenesis/triggers development of secondary sex characteristics/stimulates growth of testes, scrotum and penis/ causes production of pubic hair, axillary hair, and facial hair/spontaneous erections occur and nocturnal emissions produce “wet dreams”/vocal cords become longer and thicker/ sebaceous glands secrete more sebum/stimulates male sex drive
Secretion of gonadotropins is controlled by a
hypothalamic “gonadostat” that monitors testosterone levels in the blood.
low levels of testosterone cause hypothalamus to release
GnRH
testes also produce and release the
hormone inhibin, which will inhibit the anterior lobe of the pituitary gland from releasing FSH
Spermatogenesis
is the process by which the testes produce haploid sperm
Diploid (2N) spermatogonia lining the inner walls of the seminiferous tubules divide by
mitosis/ some resulting cells remain as spermatogonia
some resulting cells become primary spermatocytes
During the reduction division of meiosis, each primary spermatocyte
enlarges and divides to produce a pair of haploid (N) secondary spermatocytes.
During the equatorial division of meiosis, each secondary spermatocyte divides to
produce a pair of haploid (N) spermatids./four haploid spermatids will be produced from each primary spermatocyte
Spermiogenesis
a maturation process that converts spermatids into spermatozoa
spermatozoa
remain attached to Sertoli cells until they mature/mature at a rate of more than several hundred million per day
head of a sperm contains
nucleus and acrosome/ acrosome contains enzyme
Spermatogenesis takes an average of ____days
74 days and starts when a male undergoes puberty and continues until he reaches an age when testosterone
levels become ineffective
The human sexual response cycle can be divided into
four or five arbitrary phases
Sexual arousal is controlled by
by limbic system in the cerebrum, which is linked to centers throughout the brain where various stimuli can “turn on” the “sex center” to initiate the male sex drive.
during male arousal signals from spinal cord release
nitric oxide into the blood/increased blood flow fills corpora cavernosa with blood/muscle tension increases throughout body/dartos and cremaster muscles contract and pull testes closer to body/external urethral orifice dilates
plateau phase of male sexual arousal
sex flush appears as skin becomes redder/ testes are drawn closer to body and may increase in
size/parasympathetic division stimulates bulbourethral glands to release fluids to lubricate glans penis/emission occurs when sperm move through ejaculatory
ducts into urethra/ seminal vesicles and prostate gland secrete fluids urethral sphincters contract
male ejaculation
muscles in walls of male ducts contract in response to signals from sympathetic division/ rhythmic contractions of skeletal muscles at base of penis cause expulsion of semen/ ejaculation releases several hundred million sperm
refractory period occurs when
penis remains semi-erect, but cannot return to full erection/ refractory period becomes longer as a male grows older/blood leaves corpora cavernosa and penis returns to its flaccid state
Testicular cancer
most common cancer in males between the ages of 15 and 34
most testicular cancers are due to
abnormal sperm-producing cells
early symptoms of testicular cancer and treatments
early sign may be a lump in testis accompanied by discomfort or pain
early stages may be asymptomatic
treatment involves orchiectomy followed by chemotherapy
inguinal hernia
can occur when a loop of the intestine descends into the scrotum before the inguinal canal closes
Prostatitis
is an inflammation of the prostate gland caused by bacterial infection
acute prostatitis tends to be common among
sexually active men
symptoms and treatment of prostatitis
prostate gland becomes swollen and tender/ antibiotics and increased fluid intake are effective treatment
Benign prostatic hyperplasia (BPH)
is a non-cancerous and non-inflammatory enlargement of the prostate gland that occurs in one of every three males over age 60/probably due to changing hormone levels
BPH may lead to
compression of the urethra/ symptoms include painful or difficult urination, bed-wetting, and incomplete emptying
transurethral resection of the prostate (TURP)
surgically removes pieces of prostate gland/
drugs, microwaves, or radio frequency incineration can also be used to treat BP
Prostate cancer
second leading cause of cancer death among males over age 50./elevated blood levels of acid phosphatase or prostate-specific antigen indicate a tumor has
spread from prostate gland
• tumors tend to form near periphery of prostate gland
Erectile dysfunction (impotence
is the inability to attain and maintain an erection long enough to engage in satisfactory sexual intercourse.
<may be caused by aging, cardiovascular disease, neurological disorders, medications, or psychological factors/Viagra, Cialis, and Levitra can supplement existinglevels of NO within one hour
The female gonads develop from
mesoderm in the embryo./absence of Y chromosome and its sex-determining gene allows undifferentiated gonads to develop into ovaries
The female reproductive ducts develop from
the paramesonephros in the embryo
absence of testosterone prevents
mesonephros from developing/ and lateral buttresses from enlarging/ prevents labioscrotal swellings from fusing together
absence of Muellerian-inhibiting factor allows
Muellerian ducts to develop
The female external genitalia develop from
the genital tubercle
female gonads.
ovaries
ovaries
cytogenic because they produce new oocytes/ovaries function as endocrine glands to produce estrogens and progesterone
estrogen refers to
a collection of hormones
ovary is roughly the size and shape of an
almond and it is suspended in the pelvic cavity by a collection of ligaments
broad ligament
attaches ovary to back of uterus
ovarian ligament
attaches medial surface to uterus
suspensory ligament
attaches lateral surface to wall of pelvic cavity
germinal epithelium of the ovary
covers its surface/tunica albuginea is inside
stroma is at center of ovary
cortex is involved in egg development/medulla contains ovarian blood vessels, lymph vessels, and nerve
During embryonic development, primordial germ cells
migrate to a
developing ovary, which causes the primary sex cords to grow into the germinal epithelium
during embryonic development
cortex expands, medulla contracts, primary sex cords degenerate
ovary is homologous to a
testis
cells in medulla that surround primordial germ cell
become
follicle cells
follicle cells are homologous to
interstial cells of leydig
primordial germ cells become
ogonia- which are homologous to spermatagonia
uterine (Fallopian) tubes
contain smooth muscle and they are lined with cilia and they extend laterally from an ovary toward the uterus.
The distal, funnel-shaped end of a Fallopian tube is the
infundibulum
fimbriae “catch”
oocytes from ovary
where fertilization usually takes place
Beyond the infundibulum is an enlarged ampulla
uterus
is a hollow, muscular organ roughly the size and shape of a pear and it is located between the urinary bladder and the rectum
broad ligamenta
holds uterus in place
uterosacral ligaments
attach uterus to sacrum
round ligaments
attach uterus to external genital
fundus
dome-shaped portion of uterus
perimetrium
covers uterus
endometrium
is highly vascular mucous membrane lines uterine cavity
stratum functionalis
proliferates monthly
stratum basalis
permanent source for replacement of stratum functionalis
myometrium
thick layer of smooth muscle causes labor contractions and cramps
vagina
fibromuscular tube that extends from the cervix to the vaginal orifice
inner epithelium of vagina forms vaginal rugae
that secrete mucus and other substances to produce an acidic environment
The vaginal orifice is partially to fully covered at birth by a
thin membranous hymen that usually ruptures during childhood activity
female copulatory organ
vagina, forms the lower portion of the birth canal, and
provides a passage for menstrual flow out of the body.
Fallopian tubes form from
upper, unfused, funnel-shaped ends of Muellerian ducts
female external genitalia are collectively referred to as the
vulva or pudendum.
mons pubis
is a mound of fatty tissue covered with skin and coarse hair that cushions the pubic symphysis and vulva during sexual intercourse
labia majora
are fleshy folds covered by pubic hair that extend from the mons pubis
clitoris
is a nodule of erectile tissue at the anterior junction of the labia minora.
shaft contains corpora cavernosa clitoris
spongy erectile tissue
glans clitoris
extremely sensitive to touch
female vestibule is the area enclosed by the
labia minora
urethral orifice is located behind
clitoris
vestibular bulbs
are masses of erectile tissue located deep in labia majora/during sexual arousal they become engorged with blood
greater vestibular glands (bartholins)
produce and secrete mucus during
sexual arousal
Skenes glands
produce secretions to keep urethral orifice moist and lubricated
genital tubercle differentiates into the
vulva in the absence of testosterone
urethral folds become
labia minora because they dont fuse/lateral buttresses disappear
labioscrotal swellings remain unfused and become
labia majora
clitoris is homologous to
the penis
labia majora is homologous to
scrotum
female posterior opening of the urethral groove becomes
vaginal orifice which grows inwards to form lower vagian
female anterior opening of urethral groove becomes the
external urethral orifice which grows inward from this opening to form urinary bladder
Lateral growths along the urethra become
Bartholin’s glands and Skene glands
Bartholin’s glands form ducts that link them with vagina and are homologous to
bulbourethral (Cowpers) glands
skenes glands are homologous to
prostate gland
breasts
located above pectoralis major muscles and supported by suspensory ligaments
coopers droop
as a female grows older suspensory ligaments become weaker causing her breasts to sag
areola
contains sebaceous glands to keep nipple soft when infant nurses
The internal mammary glands are actually
modified s
weat glands from the integument that consist of
15 to 20 lobes subdivided into lobules.
myoepithelial cells along length of lactiferous ducts contract and force
milk towards nipple
lactiferous sinuses
where milk can be temporarily stored when mother is nursing
Ovarian cysts
arise from follicles that continue to grow, accumulate fluid, and produce hormones./retention of a cyst may cause hormonal and fertility problems/rupture of a cyst may cause bleeding and acute pain
Ovarian cancer
difficult to diagnose because it produces nondescript symptoms, such as slight pelvic discomfort, bloating, and/or fatigue/ usually not found until it spreads
most ovarian cancers result from
abnormal epithelial cells on surface of ovary/more often a woman ovulates, the greater her risk/pregnancy and nursing can reduce number of ovulations/ smoking and family history put one at risk
examination of external genitalia can identify
irritation, genital lesions or growths, or abnormal
discharge from vagina/internal examination allows vaginal walls and cervix to be examined visually
Pap exam(screening test)
removes cells from cervix and cervical canal/ Pap test is usually 90 to 95% reliable for detecting precancerous conditions of cervix
Cervical cancer
cervical dysplasia is precancerous condition that changes shape, growth rate, and quantity of cervical cell/pap smears can detect
human papilloma virus is a principal cause of
cervical cancer
who is at risk for cervical cancer and hows it treated
women who become sexually active early in life
• women with multiple sexual partners
• women who use oral contraceptives
• women, especially teenagers, who smoke cigarettes
<treatment of cervical cancer involves removal of lesions, radiation therapy, chemotherapy and/or hysterectomy
Endometrial cancer
invades the inner lining of the uterus and is most common among women between 50 and 64, although women who have never been pregnant, women who are obese, and/or women who have diabetes tend to have a higher risk/irregular menstrual bleeding is often an early symptom
Endometriosis
describes the growth of endometrial tissue outside of the uterus because of menstrual reflux through the Fallopian tubes into the pelvic cavity./endometrial tissue may attach to ovaries, kidneys,bladder, or abdominal wall/ can cause per-menstural pain
ectopic pregnancy
occurs when a fertilized egg implants outside the uterine cavity, usually in the ampulla of a Fallopian tube, and produces a “tubal pregnancy
who is at risk for developing an ectopic pregnancy
women who use an intrauterine device for birth control/women who have developed pelvic inflammatory disease/ women who smoke cigarettes
Fibrocystic disease
of the breast is the most common cause of breast lumps, which are fluid-filled cysts or alveolar thickening./lumpy, swollen, tender breasts develop a week before menstruation
Fibroadenomas
are fibrous or solid tissue masses that are usually benign
Breast cancer
most common among post-menopausal women over 50 and approximately one of eight women in U.S. will develop breast cancer/ familial breast cancer is hereditary/ woman has two defective copies of BRCA1 gene in her breast cell
spontaneous breast cancer occurs in individuals with no prior history
women who are childless or who had their first child after age 34
• women who began menstruation before age 12
• women who entered menopause after age 50
• women who smoke cigarettes
<more than 70% of breast cancers lack any identifiable risk factor
base-line mammogram should be taken between
35-40 years
lumpectomy
removes only tumor if cancer has not spread
simple mastectomy
removes breast tissue and axillary lymph nodes if cancer has spread
radical mastectomy
removes breast, lymph nodes, underlying pectoralis muscle and fascia/ rarely used
Herceptin
uses bioengineered antibodies to jam estrogen receptor
Tamoxifen
antiestrogen that blocks estrogens/recommended for pre-menopausal females
Femora
disables an enzyme needed to make estrogens
• reduces risk of cancer reoccurring in post-menopausal female
Anatomical and physiological changes in a girl’s body are controlled by hormones that lead to sexual
maturity typically beginning at age
10 or 11 and ending between 15 and 17
With the onset of puberty, GnRH is released from the hypothalamus and triggers the
anterior lobe of pituitary gland to produce and release two gonadotropins
Follicle stimulating hormone (FSH) travels from the
anterior lobe of the pituitary gland through the
blood to the ovaries to stimulate follicle cells to
divide.
<follicle cells produce and release estrogens
Luteinizing hormone (LH) travels from the anterior lobe of the pituitary gland through the
blood to the ovaries where it stimulates the differentiation of cells in a developing follicle and eventually triggers ovulation
in a female adrenal testosterone initiates
growth spurt and pubic hair
estrogens cause
breast development and maturation of ovaries, Fallopian tubes, uterus, vagina
first ovulation typically occurs around the age
14
Oogenesis is the process by which
haploid oocytes are produced in the ovaries.
<begins before birth, pauses during childhood, accelerates at puberty, occurs on a monthly basis until female goes through menopause
Primordial germ cells (PGC) migrate to developing ovary during
embryonic development, where they
become enclosed in a layer of cells and form a primordial follicle.
each primordial follicle contains a
diploid oogonium(egg mother cell)/oogonia dont undergo mitosis
how much body fat is needed for a girl to start menache
17%
An oogonium grows within its primordial follicle and becomes a
primary oocyte, which causes the
primordial follicle to become a primary follicle
primary oocyte starts meiosis
but process is suspended during Prophase I
With the onset of puberty, several primary follicles will start to
develop each month/only 1-3 mature
follicle cells change shape and divide repeatedly to form layers of granulosa cells around a
primary oocyte/ produce and secrete zona pellucida
developing structure becomes a secondary follicle
cells near oocyte secrete liquor folliculi that accumulates within follicle and forms antrum
growing antrum causes the secondary follicle to
become a
Graafian follicle
primary oocyte resumes Meiosis and completes reduction division
which forms large secondary oocyte and smaller polar body
If a sperm penetrates the wall of a secondary oocyte,
Meiosis II will be completed, which forms a
large haploid ovum and a smaller, non-functional second polar body
The empty Graafian follicle remains in the ovary and gets transformed into a
corpus luteum, which produces high levels of progesterone and some estradiol until it eventually degenerates to form a corpus albicans.
sexual arousal in the female
signals are sent to vagina which cause Bartholin’s
glands to secrete lubricating mucus
<blood supply to the breasts increases
Stimulation of the nipples and/or clitoris leads to
the
plateau phase.
<breasts increase in size
ovarian cycle
describes events associated with maturation and release of an oocyte
uterine cycle
describes regular, recurring changes in uterus
A “typical” reproductive cycle ranges from
24-35 days
We will use a hypothetical cycle of
28 days, with Day 1 of the cycle defined as the day on which menstrual bleeding begins
On Day 2 or Day 3,
the hypothalamus produces and releases GnRH to stimulate the anterior lobe of the pituitary gland to release FSH
pre-ovulatory phase
This is the time between the end of menstrual bleeding and ovulation, typically occurring from Day 6
to Day 13 of a 28-day cycle, although it can be quite variable
follicular phase describes events associated with
ovarian cycle
proliferative phase describes events associated with
uterine cycle
Secretion of estradiol from granulosa cells in developing follicles cause
changes to occur in the female reproductive tract.<
stratum basalis produces a new stratum functionalis
<lining of vagina thicken
Rising levels of estradiol exert
positive feedback on the hypothalamus, which causes it to continue releasing GnRH.
<GnRH stimulates anterior lobe of pituitary gland to release a surge of LH
Ovulation typically occurs
on Day 14 of a 28-day cycle
Post-ovulatory phase
the time between ovulation and the onset of
menstrual bleeding, typically lasting from Day 15
to Day 28 of a 28-day cycle
luteal phase describes events associated with
ovarian cycle
secretory phase describes events associated with
uterine cycle
post-ovulatory/Rising levels of progesterone secreted by the corpus luteum exert
negative feedback on the hypothalamus, which inhibits the secretion of GnRH
post-ov/absence of GnRH prevents anterior lobe of pituitary gland from releasing
FSH so no additional ovarian follicles will develop
post-ov/Rising levels of progesterone stimulate the development of the
endometrium.
<uterine glands fill with glycogen
If a fertilized egg implants in the endometrium
the corpus luteum has to be maintained in order to
produce and secrete the hormones needed for pregnancy to continue.
If fertilization does not occur, the corpus luteum
degenerates by
Day 25 of a 28-day cycle.
<levels of estradiol and progesterone decline sharply triggers menstruation
Menstruation (menses) occurs from
Day 1 to Day 5 of the next 28-day cycle.
A sharp decline in progesterone levels constricts the spiral arteries that supply the endometrium,
causing
ischemia that leads to the death of the endometrial tissue
total menstrual discharge ranges between
50-150mL
Premenstrual syndrome
refers to a collection of physical, physiological, and emotional symptoms that appear between three and ten days prior to the start of the menses.
<treatment with vitamins, diuretics and prostaglandin inhibitors may reduce symptoms
Dysmenorrhea
refers to difficult menstruation accompanied by painful cramps caused by powerful contractions of uterine smooth muscle when the endometrium is sloughed off.
<high levels of prostaglandins in blood constrict endometrial blood vessels• reduces blood flow to myometrium
Mittelschmerz
describes pain in the lower abdomen at the time of ovulation, probably because of irritation of nerve endings in the lining of abdominal cavity when blood and/or follicular fluid is released after a Graafian follicle ruptures
Amenorrhea
is a lack of menstrual periods in post-pubescent, non-pregnant females
primary amenorrhea
is failure to start menstruating by age 16
• almost always caused by abnormally low body fat
• may be caused by endocrine disorders or genetic disorders
secondary amenorrhea
is absence of menstrual periods for six months or more• usually due to reduction in percentage of body fat
Toxic shock syndrome
is caused when Staph aureus bacteria invade the bloodstream from the skin and produce deadly toxins.
<symptoms include high fever, vomiting, diarrhea, muscle aches, fatigue, and dangerous drops in blood pressure
A female’s monthly reproductive cycle comes to a halt between the
45-60
Reduced levels of estradiol fail to trigger ovulation, so a
corpus luteum does not form.
<less estradiol and progesterone get secreted
Changing hormone levels during menopause cause
dizziness, headaches, insomnia, anxiety, or depression.
<accompanied by profuse sweating
Fertilization
is the union of a sperm with an egg to form a zygote.
<typically occurs in ampulla of a Fallopian tube
Semen is deposited in the vagina as a liquid, but
fibrinogenase converts fibrinogen into a fibrin clot
within one minute to prevent semen from leaking out
of the vagina, and also to protect the sperm from the acidity of the vagina.
after about 20 minutes, vaginal acidity is
and sperm can survive so semen clot liquifies
shortly before ovulation, cervical mucus become
thinner to facilitate passage through cervix
uterine cavity is filled with a
watery fluid through which sperm can easily pass
Only a few thousand sperm survive to enter the
Fallopian tubes and they move through the Fallopian
tubes assisted by ciliary action.
<only 50 to 100 sperm will actually reach a secondary oocyte
capacitation
probably removes a protective coating from head of a sperm that block release of acrosome enzymes needed for penetration of secondary oocyte
The secondary oocyte responds to sperm penetration
by
blocking the entry of more than one sperm, which prevents polyspermy from occurring.
<secondary oocyte completes second meiotic division
If two oocytes are released during ovulation and each gets penetrated by a separate sperm
, two eggs may be fertilized and dizygotic (fraternal) twins result
Approximately 30 hours after fertilization
the zygote divides by mitosis and forms two identical daughter cells.
sperm can survive for
7 days in reproductive tract so fertilization can occur during 1 week window of opportunity
Mitotic divisions continue to occur every
16 to 20 hours, which produces a collection of blastomeres that form a solid morula.
<these divisions occur quite rapidly and blastomeres get progressively smaller/ morula remains same size as zygote
The cells of the morula become tightly packed through
compaction and blastomeres of unequal size begin to form, which creates a hollow blastocyst.
<larger cells inside trophoblast make up inner cell mass
If a single zygote separates completely during cleavage
monozygotic (identical) twins will result
When a blastocyst comes into contact with the endometrium, the risky process of
implantation begins.
<spontaneous abortions (miscarriages) may occur at this time 2 out of 3 wont implant due to genetic abnormalities
As a blastocyst begins to implant, cells of the trophoblast
divide and differentiate and grow into the endometrium to anchor the blastocyst in place and the inner cell mass separates from the trophoblast and differentiates into the primary germ layers of the embryo
ectoderm will form
skin, hair, nails, neural tissue, and linings of mouth and throat
mesoderm will form
bone, cartilage, muscle, and parts of heart, kidneys, and gonads
endoderm will form
most of gut and parts of liver and pancreas, linings of digestive tract and respiratory tract, and reproductive ducts
yolk sac develops from
endoderm and mesoderm to provide blood until liver is est. and is source of primordial germ cells that migrate to gonads
amnion develops from
ectoderm and mesoderm to surround embryo/ fills with amniotic fluid which cushions and protects embryo also maintains temp and pressure
allantois develops from
endoderm near base of yolk sac
• blood vessels in allantois become umbilical vein and umbilical arteries/ contributes to development of urinary bladder
chorion develops from
mesoderm and forms finger-like chorionic villi that penetrate endometrium to est. network of blood vessels
The placenta forms in part from
maternal tissue and in part from embryonic tissue
Chorionic villi contain blood vessels and grow into
the
endometrium, where they get surrounded by
maternal blood sinuses to form the placenta
placenta serves as a
selectively permeable barrier/ blood is never exchanged and materials “cross the placenta” by simple diffusion
The amnion fuses with the
chorion and they surround the allantoic blood vessels to form an umbilical cord.
<umbilical cord attaches belly of embryo to middle of placenta
umbilical vein carries blood
that is rich in oxygen and nutrients from placenta to embryo
umbilical arteries carry blood that
that contains carbon dioxide and wastes from embryo to placenta to be eliminated
A full-term pregnancy (gestation) lasts for approximately
9 months or 40 weeks or 266 days and can be divided into two major periods
embryonic stage typically refers to
first 8-10 weeks of gestation characterized by development of major organ systems in embryo
fetal stage typically refers to the
last 30 to 32 weeks of gestation characterized by organ growth and maturation of the fetus
The corpus luteum in the ovary secretes
estrogens and progesterone to maintain the endometrium and prepare the mammary glands for lactation
Chorionic villi secrete human chorionic gonadotropin (hCG) to maintain
the corpus luteum, which prevents menstruation that would eliminate the developing embryo.
<hCG levels may be cause of nausea and vomiting associated with morning sickness
falling progesterone levels increase
sensitivity of uterine smooth muscles to oxytocin
oxytocin is released from the
the posterior lobe of the pituitary gland to stimulate uterine smooth muscle contractions
relaxin is produced by
placenta to soften pubic symphysis and dilate cervix
Two to three weeks before labor begins
the fetus drops lower into the pelvic cavity in a process
called “lightening”, which reduces the pressure on
the mother’s abdomen and diaphragm making it easier for her to breathe
During the last week of gestation
the fetus will rotate in the uterus in order to present itself for delivery.
<head of fetus usually moves into cervix
true labor is characterized by contractions that become
stronger at regular intervals
Stage I involves
cervical effacement and dilation and lasts from four to 24 hours.
<contractions occur at short intervals
Stage II involves
expulsion of the fetus and lasts from 15 minutes to two hours.
episiotomy
performed if vaginal canal is too small to permit passage/ an incision is made from vagina to anus
if complications occur during delivery,
cesarean section can be performed
• in a breech birth, feet would be delivered first, umbilical cord could become tangled around baby’s neck
• baby might be too large to be delivered vaginally
• placenta might detach prematurely cause hemorrhage
Stage III
involves expulsion of the placenta within 15 to 30 minutes after parturition.
<forceful contractions constrict uterine blood vessel to reduce hemorrhage
Actual milk production is stimulated by the hormone
prolactin (PRL)
high levels of estrogens and progesterone during pregnancy cause hypothalamus to release
prolactin-inhibiting hormone (PIH)
elimination of placenta during afterbirth reduces
levels of estrogens and progesterone and allows prolactin to stimulate alveoli in breasts to produce milk
The principal stimulus that maintains milk production is
the sucking action of the infant
milk-ejection reflex
sensory nerves in nipples send signals to hypothalamus
can become a conditioned reflex by hearing baby cry or seeing it suck its thumb
The first liquid produced by the mammary glands is
a
yellowish fluid called colostrum that is high in protein, but lower in lactose and fat than milk.
<contains important antibodies and iron-binding proteins
Breast feeding maintains higher levels of
oxytocin in a mother’s bloodstream, which causes
contractions of uterine smooth muscles that can help restore the uterus to its pre-pregnant state
Breast feeding may provide natural contraception for some women because nursing will reduce
GnRH secretion by the hypothalamus, which reduces the amount of FSH and LH released by the pituitary gland.
<reduction in FSH and LH will inhibit follicle development and ovulation
