A&P Final Exam Flashcards
Adrenal Medulla
innervated by sympathetic neurons (Chromaffin cells)
Releases norepinephrine or epinephrine (small amounts of dop)
Causes increased:
BP, heart rate, blood flow to skelatal muscle, pulmonary air flow
Inhibits digestion and urination
Chromaffin cells
modified neurons - secretory cells that release into blood stream
adrenal cortex
Produces 25 steroid hormones (corticosteroids)
Categories of Corticosteroids
- mineralocorticoids: regulates electrolytes
- glucocorticoids - regulate metabolism of glucose
- sex steroid - repro. functions (androgens)
Zona glomerulosa (adrenal cortex)
secretes aldosterone in resp to blood Na content and angiotensin 2 from lungs
Increases reabsorption of Na+ and water in kidneys, maintains blood volume
Aldosterone
principle mineralocorticoid produced in zona glomerulosa
Zona Fasciculata and reticularis glucocorticoids
primarily secretes cortisol in resp to ACTH from anterior pituitary
Regulates metabolism by stimulating fat and protein catabolism, as well as as release of fatty acids and glucose into blood (makes nutrients available for ATP production)
Anti-inflammatory effects (steroid creams)
inhibits white blood cells and reduces release of histamine from mast cells, decreases capillary permeability
Androgens from Zona Fasciculata and reticularis
small amounts of androgens produced
Major androgen: dehydroepiandrosterone –> testosterone (large quantities produced in testes, so this is unimportant for males in this location; important for females (sex drive))
Estradiol (adrenal estrogen)
Estradiol
while ovaries produce much more than that derived from zona fasciculata and reticularis, helps to sustain bone mass after menopause
Pancreatic Hormone
1-2 million pancreatic islets producing hormones
clusters of endocrineccells
other 98% of organ produces digestive enzymes (exocrine)
Pancreatic Hormone
1-2 million pancreatic islets producing hormones
clusters of endocrine cells
other 98% of organ produces digestive enzymes (exocrine)
Pancreatic Islets
types of cells: alpha, beta, delta, PP (F), G
alpha cells
glucagon raises blood glucose levels by increasing rates of:
glycogen breakdown in skeletal muscle
glucose release by liver
fat breakdown in adipose
beta cells
insulin secreted after meal with carbohydrates raises glucose blood levels
stimulates glucose and amino acid uptake
nutrient storage effect (stimulates glycogen, fat, and protein synthesis)
stimulation of fatty acid absorption in adipocytes)
Delta Cells
produces somatostatin
inhibits GH (it’s GHIH)
secreted concurrently with insulin
may modulate secretion of alpha and beta cells
G cells
secrete gastrin which stimulates stomach secretions, motility, and emptying
PP (F) cells
produce pancreatic polypeptide (PP)
inhibits gallbladder contractions and regulates production of some pancreatic enzymes
Thrifty genotype
high rates of obesity
rapid production of insulin when food is ingested
permits body to lay down efficiently
may be adapted to environments characterized by feast and famine
Regulation of glucagon and insulin secretion
Low blood glucose stimulates release of glucagon
High blood glucose stimulates secretion of insulin
Corpus luteum
follicle after ovulation
produces estradiol and progesterone for 12 days or 8-12 weeks with pregnancy
Functions of estradiol and progesterone
development of female reproductive system and physique including bone growth
regulates menstrual cycle, sustains pregnancy
Preps mammary glands for lactation
interstitial cells of testes
exists between seminiferous tubules
produces testosterone and estrogen
functions of testes
development of male reproductive system and physique
Sustains sperm production and sex drive
Sustentacular sertoli cells (nurse cells)
secretes inhibin which suppresses FSH secretion and stabilizes sperm production rates
Heart
atrial natriuretic peptide (AMP) released in response to low BP by raising it
Skin
keratinocytes helps produce D3, first step in synthesis of calcitriol
Liver
converts vitamin D3 to calcidiol
source of IGF (insulin-like growth factor) that works with GH
secretes about 15% of erythropoietin
Secretes angiotensinogen
precursor of angiotensin 2 (vasoconstrictor) raises BP
Kidneys
converts calcidiol to calcitriol (active form of vit D)
incr. absorption by intestine and inhibits loss in urine
more Ca2+ available for bone deposition
produces 85% of erythropoietin
converts angiotensinogen to angiotesin 1 with renin
erythropoietin
stimulates bone marrow to produce RBC’s
Lungs
converts angiotensin 1 to angiotensin 2 (vasoconstrictor)
stomach and small intestines (10 enteric hormones)
coordinate digestive motility and secretion
Placenta
secretes estrogen, progesterone, and others
regulates pregnancy, stimulates development of fetus and mammary glands
down regulation of hormone receptors
receptors are degraded, decrease sensitivity of target cell to hormone
Up regulation of hormone receptors
targets tissue more sensitive to the hormone and increase receptor production
Gen mechanism of hormone action
hormone binds to cellular surface or receptor inside target cell
cell may then synthesize new molecules, change permeability of membrane, or alter rates of reaction
Permissive effect
second hormone that strengthens effects of first
ex: estrogen stimulates up regulation of progesterone receptors in uterus
synergistic effect
two hormones acting together for greater effect
Ex: estrogen and LH both needed for oocyte development
FSH and testosterone both needed for sperm production
Antagonistic effect
two hormones with opposite effects
insulin promotes glycogen formation and glucagon stimulates glycogen breakdown
stress response
set of bodily changes called general adaptation syndrome (GAS)
Primary sex organs
organs that produce the gametes (testes or ovaries)
Secondary sex organs (accessory but essential for reproduction)
male = ducts, glands, and penis females = uterine tubes, uterus, vagina that receive sperm and nourish the developing fetus
Secondary sex characteristic
features that develop at puberty to attract a mate
pubic, axillary and facial hair, scent glands, body morphology
Somatic cells (diploid)
23 pairs of chromosomes for total of 46
each pair is homologous - contains similar genes
one member of each pair is from each parent
22 autosomes and 1 pair of sex chromosomes (either X or Y)
Gametes (haploid cells)
single set of chromosomes for total of 23
produced by special type of division: meiosis
Testes
paired oval glands measuring 2 in by two inc
surrounded by dense CT white capsule (tunic albuginea)
Fibrous partitions (septa) form 200-300 lobules
Each is filled with 2 or 3 seminiferous tubles where sperm are formed
Tunica Vaginalis
serous membrane (visceral and parietal layer) that is the piece of peritoneum that descended with testes into scrotal sac, superficial to tunica albiquinea allows for easier movement of testes with scrotum
seminiferous tubules
contains all stages of sperm development: spermatagonia, primary spermatocyte, secondary spermatocyte, spermatid, and sperm
supporting cells = sertoli cells (nurse cells)
Leydig cells
exists in between tubules, secretes testosterone
Sertoli cells
extends from basement membrane to lumen
forms blood-testis barrier
support developing sperm cells
produce fluid and control release of sperm into lumen
secrete inhibin, slows sperm production by inhibiting FSH
Support of spermiogenisis by surrounding and unfolding spermatids by providing nutrients and chemical stimuli that promote development
supports mitosis andmeiosis (promote division in response to FSH)
Blood testis barrier (similar to BBB)
essential for preserving differences between tubular fluid and interstitial fluid
prevents immune system from attacking spermatazoa
Spermatogenesis
spermatagonia produces 2 kinds of daughter cells
Type A - remains outside blood-testis barrier and produce more daughter cells until death
Type B - differentiates into primary spermatocytes
(cells must pass through BTB to move inward towards lumen – new tight junction forms behind these cells)
Spermatagonia
stem cells
spermiogenesis
transformation of spermatagonia into spermatozoon (sprouts tail and discards cytoplasm to become lighter)
4 spermatids are formed, with each being haploid and unique
all four remain in contact with cytoplasmic bridge
accounts for synchronized release of sperm that are 50% x chromosome and 50% y chromosome
maturation of spermatid into sperm cells
changes that form spermatid into spermatazoa, discarding excess cytoplasm and growing tails
Anatomy of sperm
head:
nucleus contains haploid set of chromosomes
acrosome contains hyaluronidase and proteinase enzymes that penetrate egg
tail:
midpiece contains mitochondria around flagella (produces ATP for flagellar movement)
Puberty
surge of pituitary gonadotropins (LH, FSH) begins development
continues until first menstrual period or first ejaculation of viable sperm
Brain-testicular axis
mature hypothalamus produces GnRH
stimulation of gonadotroph cells in anterior pituitary causes secretion of FSH and LH
Causes enlargement of secondary sexual organs
Testosterone sustains spermatogenesis throughout adulthood
Controlling testosterone production
negative feedback system controls blood levels of testosterone
receptors in hypothalamus detects increase in blood level
secretion of GnRH slowed
anterior pituitary (FSH and LH) hormones slowed
Leydig cells of testes slowed
Blood level returns to normal
Inhibin hormone
nurse cells release inhibin when you got enough sperm, inhibits FSH secretion by anterior pituitary and decreases sperm production
Pathway of sperm flow through ducts of testis
seminiferous tubules straight tubules rete testis efferent ducts ductus epididymis ductus (vas) deferens
Spermatic ducts
efferent, epididymis, ductus deferens, and ejaculatory duct
Epididymis
Head, body, and tail
6 m long coiled duct adhering to posterior of testis
site of sperm maturation and storage (fertile for 60 days)
Efferent ducts
12 small ciliated ducts collecting sperm from rete testes and transporting it to the epididymis
Ductus (vas) deferens
causes peristalsis during orgasm
muscular tube 45 cm long passing up from scrotum through inguinal canal to posterior surface of bladder
Ejaculatory duct
2 cm duct formed from ductus deferens and seminal vesicle and passing through prostate to empty into urethra
Pathway of Ductus Vas Deferens
Ascends along posterior border of epididymis
passes up through spermatic cord and inguinal ligament
reaches posterior surface of urinary bladder
empties into prostatic urethra with seminal vesicle
lined with pseudostratified columnar epithelium and covered with heavy coating along through peristaltic contractions
Male urethra
8 inch long passageway for urine and semen
membranous urethra
Prostatic urethra (1 inch long)
membranous urethra (passes through UG diaphragm)
penile (spongy) urethra (through corpus spongiosum)
Seminal vesicles
pair of pouchlike organs found posterior to base of bladder
filled with viscous fluid used to neutralize vaginal acid and male urethra, has fructose for ATP, prostaglandins to stimulate sperm motility and viability, and clotting proteins for coagulation of semen
Prostate gland
single organ size of chestnut found inferior to bladder
secretes milky fluid that increases sperm motility and viability
citric acid for ATP production and enzymes for seminal liquefaction
enlarges with age
Bulbourethral (Cowper’s) Gland
paired, pea-sized gland within UG diaphragm that secretes alkaline mucous into spongy urethra
neutralizes acids and lubricates
Semen
60% seminal vesicle fluid, 30% prostatic, 10% spem
normal sperm count = 50-150 million/mL
Cross section of penis
corpora cavernosa (upper paired, erectile tissue masses) corpus spongiosum (lower erectile tissue mass that surrounds urethra)
Life history of oogonia
born with 200,000 - 2 mill at birth, only 400 mature due to polar bodies
meiosis 1 resumes for the follicles prepping for ovulation so by the time they’re ready to ovulate it’s at meiosis 2
Sperm causes final stages of meiosis 2 to occur
Follicular stages
Primordial, primary, secondary, tertiary (graafian), ovulation
Primordial follicle
when oocyte is surrounded by single squamous layer of follicle cells
starting at puberty, these follicles are being continuously activated to be developed
Granulosa cells
when follicular cells have enlarge, divided, and formed several layers around growing primary oocyte
Zona pellucida
where granulosa cell and oocyte touch
Thecal cells
adjacent cells that work together with granulosa to produce estrogen
Secondary follicle
when follicular cells begin secreting small amounts of fluid that accumulates in small pockets –> gradually expands and separated inner and outer layers of follicle
Corona radiata
granulosa cells attached to zona pellucida–still attached to oocyte at ovulation
antrum
formed by granulosa cells secreting fluid
Tertiary follicle
oocyte has reached metaphase of meiosis 2 and stopped developing; first polar body has been discarded
Ovulation
Oocyte and corona radiata are ejected into the pelvic cavity
Oocyte is then moved into uterine tube by fimbriae
Formation of corpus luteum
progesterone preps uterus for preg by stimulating maturation of uterine lining and secretions of uterine glands
(if no pregnancy: empty follicle collapses and ruptured blood vessels bleed into antrum; remaining granulosa cells invade area and proliferate)
Formation of corpus albicans
marks end of ovarian cycle
fibroblasts invade corpus luteum and creates this structure
uterine/fallopian tube
a narrow, 4 inch tube that extends from ovary to uterus
infundibulum is the opening near ovary (funnel shape) that has fimbriae (finger-like processes)
central region = ampulla
where it meets the uterus = isthmus
Histology + function of uterine tube
mucosa, muscularis, and serosa
Functions – events occuring in uterine tube
Overview of ovulation
fimbriae sweep oocyte into tube, cilia and peristalsis move it along, sperm reaches oocyte, fertilization occurs within 24 hours after ovulation, zygote reaches uterus about 7 days after ovulation
Anatomy of uterus
Site of menstruation & development of fetus
subdivided into fundus,body, isthmus & cervix
mucosa
ciliated columnar epithelium with secretory cells provide nutrients & cilia move along ovum
muscularis
circular & longitudinal smooth muscle
peristalsis helps move ovum down to the uterus
serosa
outer serous membrane
histology of uterus
endometrium, myometrium, and perimetrium
endometrium
simple columnar epithelium stroma of connective tissue and endometrial glands stratum functionalis shed during menstruation stratum basalis replaces stratum functionalis each month
myometrium
3 layers of smooth muscle
perimetrium
visceral peritoneum
blood supply to uterus
Uterine arteries branch as arcuate arteries and radial arteries that supply the myometrium
branches penetrate to the endometrium
spiral arteries supply the stratum functionalis
their constriction due to hormonal changes starts menstrual cycle
endometriosis
growth of endometrial tissue outside uterus
can cover ovaries, outer surface of uterus, colon, kidneys, and bladder
Problem is tissue responds to hormonal changes by proliferating then breaking down & bleeding
causes pain, scarring & infertility
Vagina
passageway for birth, menstrual flow, and intercourse
4 inch long fibromuscular organ ending at cervix
mucosal layer =
stratified squamous epithelium & areolar connective tissue
muscularis layer = smooth muscle allows considerable stretch
adventitia = loose connective tissue that binds it to other organs
lies between urinary bladder and rectum
Female repro cycle
Controlled by monthly hormone cycle of anterior pituitary, hypothalamus & ovary
Monthly cycle of changes in ovary and uterus
Ovarian cycle
changes in ovary during & after maturation of oocyte
Uterine cycle
preparation of uterus to receive fertilized ovum
if implantation does not occur, the stratum functionalis is shed during menstruation
Female puberty
9-10 in US
Triggered by rising levels of GnRH which stimulate anterior lobe of pituitary to produce FSH & LH (follicle-stimulating & luteinizing hormone)
FSH stimulates follicles to secrete estrogen & progesterone
2nd sex organs maturation, in height & width of pelvis
prepares uterus for pregnancy
development of breasts
growth of pubic & axillary hair, apocrine & sebaceous glands
Menarche = first menstrual period (~age 12)
requires at least 17% body fat in teenager, 22% in adult
Female hormones secreted cyclically & in sequence
Hormonal Regulation of Reproductive Cycle
GnRH secreted by the hypothalamus controls the female reproductive cycle
stimulates anterior pituitary to secrete FSH & LH
FSH initiates growth of follicles that secrete estrogen
estrogen maintains reproductive organs
LH stimulates ovulation & promotes formation of the corpus luteum which secretes estrogens, progesterone, relaxin & inhibin
progesterone prepares uterus for implantation and the mammary glands for milk secretion
relaxin facilitates implantation in the relaxed uterus
inhibin inhibits the secretion of FSH
Sexual Cycle
Averages 28 days
Hormone cycle produces hierarchy of control
hypothalamus-> pituitary -> ovaries -> uterus
Follicular phase (2 weeks)
menstruation occurs during first 3 to 5 days of cycle
uterus replaces lost endometrium & follicles grow
Postovulatory phase (2 weeks)
corpus luteum stimulates endometrial thickening
endometrium lost again if pregnancy does not occur
Menstrual Phase
Menstruation lasts for 5 days
First day is considered beginning of 28 day cycle
In ovary
20 follicles that began to develop 6 days before are now beginning to secrete estrogen
fluid is filling the antrum from granulosa cells
In uterus
declining levels of progesterone caused spiral arteries to constrict – glandular tissue dies
stratum functionalis layer is sloughed off along with 50 to 150 ml of blood
Preovulatory Phase
Lasts from day 6 to 13 (most variable timeline)
In the ovary (follicular phase)
follicular secretion of estrogen & inhibin has slowed the secretion of FSH
dominant follicles survives to day 6
by day 14, graafian follicle has enlarged & bulges at surface
increasing estrogen levels trigger the secretion of LH
In the uterus (proliferative phase)
increasing estrogen levels have repaired & thickened the stratum functionalis to 4-10 mm in thickness
Ovulation
Rupture of follicle & release of 2nd oocyte on day 14
Cause
increasing levels of estrogen stimulate release of GnRH which stimulates anterior pituitary to release more LH
Corpus hemorrhagicum results
Postovulatory Phase
Most constant timeline = lasts 14 days
In the ovary (luteal phase)
if fertilization did not occur, corpus albicans is formed
as hormone levels drop, secretion of GnRH, FSH & LH rise
if fertilization did occur, developing embryo secretes human chorionic gonadotropin (hCG) which maintains health of corpus luteum & its hormone secretions
In the uterus (secretory phase)
hormones from corpus luteum promote thickening of endometrium to 12-18 mm
formation of more endometrial glands & vascularization
if no fertilization occurs, menstrual phase will begin
Breasts
Mound of tissue overlying the pectoralis major
axillary tail in armpit contains many lymphatic vessels
Nipple is surrounded by areola (colored zone)
melanocytes
smooth muscle contracts wrinkling the skin & erecting the nipple in response to cold, touch
Suspensory ligaments attach it to skin & muscle
If nonlactating, contains little glandular tissue just a system of branching ducts and fat tissue
Mammary Glands
Modified sweat glands that produce milk (lactation)
amount of adipose determines size of breast
milk-secreting glands open by lactiferous ducts at the nipple
Development of mammary glands
Lactation = synthesis and ejection of milk from mammary glands
High estrogen levels in pregnancy cause ducts to grow and branch
Progesterone stimulates budding & development of the acini at the ends of the ducts
Colostrum & Milk Synthesis
Colostrum forms in late pregnancy
similar to breast milk but contains 1/3 less fat, thinner
nutrition for first 1 to 3 days after birth
contains IgA protection from gastroenteritis
Synthesis is promoted by prolactin (from pituitary)
synthesis of hormone begins 5 weeks into pregnancy, by full term it is 20x normal level
steroid hormones from placenta oppose it until birth
At birth, prolactin secretion drops to nonpregnant levels, but 20 times with nursing events
without continuous nursing, production stops in 1 week
Only 5-10% of women become pregnant again while nursing
inhibition of GnRH & reduced ovarian cycling
Without continuous nursing decreased prolactin levels allow normal ovarian cycling
milk ejection + milk letdown
controlled by a neuroendocrine reflex
infant’s suckling stimulates sensory receptors in nipple, signaling the hypothalamus & posterior pituitary to release oxytocin
oxytocin stimulates myoepithelial cells
Myoepithelial cells surround each gland acinus
epithelial cells packed with actin
contract like smooth muscle to squeeze milk into duct
milk flow within 30-60 seconds after suckling begins
Breast milk
Colostrum & milk have a laxative effect that clears intestine (green, bile-filled fecal material in newborn)
Breast milk supplies antibodies & helps to colonizes intestine with beneficial bacteria
Nursing woman can produce 1.5L per day
inc calorie intake by 300, inc Ca+2 & vitamin D
benefits of breast feeding
Faster & better absorption of the “right” nutrients
Decreased incidence of diseases later in life
reduction in allergies, respiratory & GI infections, ear infections & diarrhea
Parent-child bonding
Infant in control of intake
aging female repro system
Hormone-directed sexual characteristics start to develop at puberty
Reproductive cycle occurs once/month from menarche (10-14) until menopause (between 40 & 50)
Fertility declines with age
decreasing number of viable eggs
less frequent ovulation
declining ability of uterus to support embryo
Menopause is cessation of menstruation
no remaining follicles to stimulate estrogen secretion
osteoporosis, hot flashes, mood swings, organ atrophy
Aging male repro system
Decline in reproductive function is more subtle (capacity may remain into 90’s)
Decline in testosterone at 55
reduced muscle synthesis
fewer viable sperm
reduced sexual desire
Enlargement of prostate (benign hyperplasia)
1/3 of males over 60
frequent urination, decreased force of stream
