Exam 4 Flashcards
The urinary system includes
2 kidneys ureters, bladder, and urethra
Kidneys produce
urine
Urteters
receive urine from kidneys. conduct urine to bladder by gravity and peristalsis
Bladder
receives and stores urine
Urethra
conducts urine from bladder to outside body
Functions of the urinary system
- adjusting blood volume and pressure
- regulating blood plasma concentrations of sodium, potassium, chloride and other ions
- stabilizing blood pH
- conserving valuable nutrients by preventing their loss in urine
- removing drugs and toxins from blood stream
Hilum
medial indentation of kidneys. point of entry/exit for the renal artery, renal nerves, renal vein, and ureter
The kidneys are connected to the urinary bladder by the
ureters
Structural landmarks of kidney
- fibrous capsule: outermost
- renal cortex
- renal medulla : renal pyramid(renal papilla is tip of pyramid) , renal column
- kidney lobe, each kidney contains 6-18
Cortical nephrons
microscopic functional units of kidneys. 85% of all nephrons. located primarily in cortex. responsible for most regulatory functions
Juxtamedullary nephrons
15% of all nephrons, long nephron loop extends deep into medulla, essential to producing concentrated urine
Segments of nephron
- renal corpuscle (filtration)
- proximal convoluted tubule (solute reabsorption of water, ions, and all organic nutrients)
- nephron loop: water reabsorption in descending limb and solute reabsorption of sodium and chloride ions in thick ascending limb
- distal convoluted tubule: secretion of ions, acids, drugs, and toxins.. variable reabsorption of water, sodium ions, and calcium ions.
- collecting duct: variable water reabsorption and variable solute reabsorption or secretion of sodium ,potassium, hydrogen and bicarbonate ions
- papillary duct: delivery of urine to minor calyx
The kidneys maintain homeostasis by
removing wastes and producing urine
Renal physiology
maintains homeostasis by regulating the volume and composition of blood. excretes solutes, especially metabolic wastes. concentrates urine to 855-1355 mOsm/L
Metabolic wastes
- Urea: most abundant organic waste. byproduct of amino acid breakdown
- creatinine: byproduct of creatine phosphate breakdown in muscles
- Uric acid: formed during recycling of nitrogenous bases of RNA
3 processes in urine formation
Filtration, Reabsorption, Secretion
Filtration
occurs only in renal corupuscle. blood pressure forces water and solutes across the membranes of the glomerular capillaries into the capsular space
Reabsorption
transport water and solutes from the tubular fluid across tubular epithelium into peritubular fluid.
Secretion
transport of solutes from the peritubular fluid across tubular epithelium into the tubular fluid
There are ___ factors that control glomerular filtration
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Glomerular hydrostatic pressure GHP
blood pressure in the glomerular capillaries. tends to push water and solutes out of plasma and into filtrate
Capsular colloid osmotic pressure
few plasma proteins enter the capsular space
Blood colloid osmotic pressure BCOP
pressure due to materials in solution. tends to draw water out of the filtrate and into the plasma. opposite of filtration
Capsular hydrostatic pressure CsHP
opposite of GHP. push water and solutes out of filtrate and into plasma. results from resistance of filtrate already in the nephron
Net filtration pressure NFP
Pressure acting across the glomerular capillaries. represents the sum of the hydrostatic pressure and colloid osmotic pressures.
Glomerular filtration rate
amount of filtrate produced each minute
Two level of control that help stabilize glomerular filtration rate
- auto regulation
- central regulation: endocrine component initiated by kidneys. neural component involved the sympathetic division of the ANS
Reabsorption in the proximal convoluted tubule includes
<99% of glucose, amino acids, and other organic nutrients. sodium, potassium, bicarbonate, magnesium, phosphate, sulfate ions. water (108 liters a day): solute concentration of tubular fluid decreases and water moves into peritubular fluid
Reabsorption and secretion along the Distal convoluted tubule
movement of water and solutes out of peritubular fluid into the tubular fluid. only 15-20% of the initial filtrate volume reaches the DCT. the combo of reabsorption and secretion alters solute concentration in tubular fluid. sodium ions are reabsorbed in exchange for potassium ions (pump stimulated by aldosterone). hydrogen ions are secreted in exchange for sodium ions to increase pH of body fluids. carrier proteins also secrete toxins or drugs
thick ascending limb
actively transports na+ and cl- out of the tubular fluid. impermeable to water. tubular fluid solute concentration decreases. peritubular fluid concentration increases. osmotic concentration of peritubular fluid is increased from activity here.
thin descending limb
permeable to water, impermeable to solutes. water moves from tubular fluid into the peritubular fluid by osmosis. tubular fluid solute concentration increases.
Concentration of urine
water is reabsorbed along the DCT and collecting duct, increasing concentration of solutes within the tubular fluid, particularly urea. tubular fluid reaching the papillary duct has a typical urea concentration of 450 mOsm/L
Obligatory water reabsorption
occurs in locations where water cannot be prevented (pct and descending limb of nephron loop). rate cant be adjusted, recovers 85% of filtrate
facultative water reabsorption
occurs in the DCT and collecting tubule. allows precise control of water reabsorption, adjusts urine volume by reabsorbing a portion of the remaining 15% of filtrate volume
urine volume without antidiuretic hormone
no water is reabsorbed in DCT and collecting tubule. no facultative water reabsorption
urine volume with adh
adh allows water channels to form. aquaporins appear in the apical plasma membranes of the DCT and collecting tubule cells. water permeability of the last tubular segments increases, increasing water reabsorption
normal urine
normal volume is 1200 ml a day with an osmotic concentration of 1000 mOsm/L . kidneys alter their main function to maintain homeostasis
function of the female reproductive system
- produce sex hormones
- produce functional gametes
- protects and supports developing embryo
- maintains growing fetus
- nourishes newborn infant
female gonads are ovaries that
produce gametes which are oocytes that mature into ova. the produce hormones
female reproductive tract
uterine tubes deliver oocyte or embryo to the uterus. normal sites of fertilization
uterus
cite of embryonic and fetal development. also site of exchange between maternal and embryonic/ fetal bloodstream.Hollow, muscular organ
Provides mechanical protection, nutritional support, and waste removal for embryo (weeks 1–8) and fetus (>8 weeks)
Contractions in the muscular wall are important in delivering the fetus at birth
ovary
paired almond shaped organs. produce immature female gametes (oocytes). secrete sex hormones (estrogen and progesterone). secrete inhibin (inhibits FSH production in the anterior pituitary gland)
oogenesis
formation and development of the oocyte. begins before birth, acerbates at puberty, ends at menopause.
steps in oogenesis
- mitosis of oogonium: completed prior to birth, for each oogonium, produces one oogonium and one primary oocyte
- meiosis I
- meiosis II
meiosis I
begins 3rd and 7th month of fetal development. primary oocytes begin meiosis I but stop at prophase I until puberty. rising FSH levels trigger start of ovarian cycle. each month some of the primary oocytes are stimulated to complete meiosis I. yields haploid secondary oocyte and a polar body. secondary oocyte gets the majority of cytoplasm. ovary releases a secondary oocyte (not mature ovum). meiosis does not complete unless fertilization occurs
meiosis II
secondary oocyte begins. suspended in metaphase II at ovulation. at fertilization the secondary oocyte divides into a secondary polar body and a mature ovum.
ovarian follicles
specialized structures where oocyte growth and meiosis I occur
stages in ovarian cycle
- Primordial follicle in egg nest
- Formation of primary follicles
- Formation of secondary follicles
- Formation of tertiary follicle
- Ovulation
- Formation of corpus luteum
- Formation of corpus albicans
Primordial follicle
inactive primary oocyte surrounded by a simple squamous layer of follicle cells
egg nests
clusters of primary oocytes in the outer portion of the ovarian cortex, near the tunic albuginea
Formation of primary follicles
Follicular cells enlarge, divide, and form several layers around the primary oocyte
Follicular cells now called granulosa cells
Zona pellucida (pellucidus, translucent)
Region that develops around the oocyte
Thecal endocrine cells (theca, box)
Layer of cells that form around the follicle
Thecal cells and granulosa cells work together to produce estrogen
Formation of secondary follicles
Follicle wall thickens, and follicular cells secrete fluid
Fluid-filled pockets expand and separate the inner and outer layers of the follicle
Formation of tertiary follicle
Occurs about day 10–14 of cycle
One secondary follicle becomes a tertiary follicle, or mature graafian follicle
Roughly 15 mm in diameter
Expanded central chamber (antrum) is filled with follicular fluid
Oocyte projects into the antrum
Granulosa cells form a protective layer (corona radiata) around the secondary oocyte
Ovulation
Tertiary follicle releases secondary oocyte and corona radiata into the pelvic cavity
Marks end of follicular phase and start of luteal phase
Formation of corpus luteum (lutea, yellow)
Empty tertiary follicle collapses
Remaining granulosa cells proliferate
Secrete progesterone and estrogens
Progesterone stimulates maturation of the uterine lining
Formation of corpus albicans
Knot of pale scar tissue produced by fibroblasts
Formed by degeneration of the corpus luteum when fertilization does not occur after 12 days
Marks the end of the ovarian cycle
Oocyte transport
Involves combination of ciliary movement and peristaltic contraction of smooth muscle in the uterine tube
Takes 3–4 days for a secondary oocyte to travel from infundibulum to the uterine cavity
Fertilization must occur within the first 12–24 hours after ovulation
layers of the uterine wall
1.Perimetrium (peri, around + metra, uterus)
Outer surface
Incomplete serosa continuous with the peritoneal lining
2.Myometrium (myo-, muscle)
Thick muscular middle layer
Smooth muscle layer provides force for childbirth
3.Endometrium
Glandular inner lining whose characteristics change with each uterine cycle
uterine cavity
Large, superior cavity continuous with isthmus of uterine tube
Internal os (os, opening or mouth)
Opening connecting the uterine cavity to the cervical canal
Cervical canal
Constricted passageway at the inferior end of the uterine cavity
Begins at internal os; ends at external os
External os
Curving vaginal opening into the uterus
Vagina
Elastic, muscular tube Extends from the cervix to the vestibule (space bordered by the labia minora) Typically 7.5–9 cm (3–3.6 in.) long Variable diameter (highly distensible) Internal passageway is the vaginal canal
Vaginal canal
Internal passageway
Lined by nonkeratinized stratified squamous epithelium
Fornix
Shallow recess in the vagina surrounding the tip of the cervix
Rugae
Folds formed by the vaginal lining when relaxed
Vulva
area containing the female external genitalia
Vestibule
Central space bounded by small folds called labia minora (singular, labium minus)
Lesser vestibular glands
Secrete onto the vestibular surface, keeping it moist
Greater vestibular glands (Bartholin’s glands)
Activated during sexual arousal
Mucous glands that discharge into the vestibule
Same embryonic origins as the bulbo-urethral glands of males
Vestibular bulbs
Masses of erectile tissue on either side of the vaginal entrance
Have the same embryonic origin as the corpus spongiosum of the penis
Mons pubis
Bulge of adipose tissue deep to the skin and superficial to the pubic symphysis
Clitoris
Projects into the vestibule
Contains erectile tissue comparable to the corpora cavernosa and corpus spongiosum of the penis
Prepuce, or hood
Extensions of the labia minora encircling the body of the clitoris
Labia majora (singular, labium majus)
Prominent folds of skin encircling the labia minora and adjacent structures
Mammary glands
Provide nourishment (milk) for developing infant Milk production (lactation) controlled by hormones released by the reproductive system and the placenta Located on the anterior chest, directly over the pectoralis major muscle.Embedded in the subcutaneous tissue of the pectoral fat pad deep to the skin
Suspensory ligaments of the breast
Bands of dense connective tissue
Surround the duct system and form partitions between lobes and lobules
Glandular tissue divided into lobes
Each lobe has several secretory lobules
Each lobule is composed of secretory alveoli. Ducts from the lobules converge into one lactiferous duct per lobe
Each lactiferous duct expands near the nipple to form a lactiferous sinus
Nipple
Conical projection where 15–20 lactiferous sinuses open onto the body surface
Areola
Reddish-brown skin around the nipple
Grainy texture from sebaceous glands deep to the surface
Ovarian and uterine cycles
Ovarian and uterine cycles are controlled by cyclical changes in hormones
Two cycles must operate synchronously for proper reproductive function
Step 1 in ovarian cycle hormonal regulation
Release of gonadotropin-releasing hormone (GnRH)
From hypothalamus
Causes production and secretion of FSH
Causes production (not secretion) of LH
Step 2 in ovarian cycle hormonal regulation
Follicular phase of the ovarian cycle
Begins when FSH stimulates some secondary follicles to become tertiary follicles
As follicles develop, FSH levels decline (as a result of negative feedback effects of inhibin)
Developing follicles also secrete estrogens (especially estradiol)
Low levels of estrogens inhibit LH secretion
Inhibition decreases as estrogen levels climb
Estrogen decreases basal body temperature about 0.3ºC (0.5ºF) lower than during the luteal phase
Step 3 in ovarian cycle hormonal regulation
Luteal phase
GnRH and elevated estrogen levels stimulate LH secretion
Massive surge in LH on or around day 14 triggers:
Completion of meiosis I by the primary oocyte
Forceful rupture of the follicular wall
Ovulation (~9 hours after LH peak)
Formation of corpus luteum
Luteal phase begins after ovulation. Corpus luteum secretes progesterone
Stimulates and sustains endometrial development
Progesterone levels increase, and estrogen levels fall
Suppresses GnRH
If pregnancy does not occur, corpus luteum degenerates
Progesterone levels fall
GnRH increases and begins a new cycle
