Endocrine, Reproductive, Urinary & Avian Flashcards
Endocrine works closely with the cardiovascular system to control & coordinate the intricate parts & functions of the body because
hormones are produced and; travel through the blood
the hormonal part of the fight or flight response is produced in the
adrenal gland
where is the antidiuretic hormone that is produced in the hypothalamus stored before its release into the bloodstream?
the neurohypophysis
the hormone that results in a rise in blood glucose when it is released into the blood stream is produced where?
the pancreas
where is the hormone that increases metabolism produced?
thyroid
the hormone that targets the ovary is
FSH
the neurohypophysis produces what hormone?
ADH
the endocrine system effects tissues
from a distance
spermatogenesis takes place in
the seminiferous tubules
what is the major cells of the testes?
interstitial cells
pampiniform plexus is formed of what?
veins
the thin membrane that is intimately adhered to the testicular surface is the
visceral vaginal tunic
what are the 2 hormones produced in the ovaries?
estrogen & progestin
what is the name of the inner lining of the uterus?
endometrium
kidneys process waste from the metabolism of what nutrient?
protein
what animal has a heart shaped kidney?
the horse
what is the basic functional group of the kidney
nephron
what nutrient is ABSENT from glomerular filtrate
protein
the function of the urinary sphincter is under
voluntary control
compared to the nervous system, how quickly does the endocrine system respond & how long does the response last?
it responds slowly to stimuli and the response lasts longer than the nervous system
what 2 hormones are produced in the adrenal medulla?
epinephrine and norepinephrine
what part of the nervous system directly influences the release of adrenal hormones?
sympathetic nervous system
what type of thyroid disease are dogs commonly afflicted with?
hypothyroidism
low levels of cortisol is identified as a malfunction of what gland?
adrenal gland
where is insulin produced in the body?
pancreas
what are the releasing factor hormones secreted by the anterior pituitary gland?
TSH FSH ACTH GH Prolactin LH MSH
what is an alternative name for the posterior pituitary?
neurohypophysis
what is an enlargement of the thyroid gland due to iodine insufficiency called?
goiter
where is erythropoietin produced?
the kidney
what additional hormone is produced in the thyroid gland?
calcitonin
endocrine gland consisting of several small nodules located in, on, or near the thyroid gland
parathyroid gland
an endocrine gland located on either side of the larynx in the neck region
thyroid gland
portion of the brain stem that has extensive links to the brain & pituitary gland
hypothalamus
2 endocrine glands located near the cranial poles of the kidneys
adrenal glands
master endocrine gland aka hypophysis
pituitary gland
endocrine & exocrine gland that produces & secretes digestive enzymes into the intestines & produces hormones
pancreas
part of the renal corpuscle that surrounds the glomerulus consisting of 2 layers
bowmen’s capsule
capillaries in the network that surround the tubular part of the nephron of the kidney that eventually converge to form the renal vein
peritubular capillaries
tuft of capillaries at the center of the renal corpuscle
glomerulus
narrowest part of the tubular portion of the nephron
loop of henle
most proximal bone of the pelvic limb aka os coxae
pelvis
inner layer of a kidney that is darker in color & has smooth striated appearance
medulla
convoluted tubule that is a continuation of ascending part of the loop of henle
distal convoluted tubule
arterioles that carry blood into the glomerulus
afferent arterioles
outer fibrous covering of the kidney
capsule
tubular structure that carries urine from the urinary bladder out of the body
urethra
basic function unit of the kidney
nephron
outer portion of the kidney where renal corpuscles & the convoluted tubules of the nephrons are located
cortex
indented area where blood vessels, nerve & lymph vessles enter & leave the kidneys
hilus
sac like organ that stores urine until it is ready to be released out of the body
urinary bladder
convoluted tubule that forms the 1st part of the kidney nephron & continues with the bowmen’s capsular space
proximal
arterioles that carry blood away from the glomerulus after is has been filtered in the renal corpuscle
efferent arterioles
muscular tube that carry urine from the kidneys to the urinary bladder
ureters
the smaller of the two penile erectile tissues
corpus cavernosum urethrae
the largest ligament that supports the female reproductive organs in the abdominal cavity
broad ligament
the outer, thick connective tissue sac around each testis
parietal (common) vaginal tunic
the most cranial of the male accessory reproductive glands (not found in the dog and cat)
seminal vesicle
the tube that connects the tail of the epididymis with the urethra
vas deferens
the inner, thin connective tissue sac that is tightly adhered to the surface of the testis
visceral (proper) vaginal tunic
a lateral fold of the broad ligament of the uterus made up of fibrous tissue and blood vessels
round ligament of the uterus (mesometrium)
where spermatozoa enter from the efferent ducts
epididymus
a ligament that comes off the cranial end of the broad ligament and attaches to the body wall near the last rib
suspensory ligament of the ovary (mesovarium)
an s-shaped bend in the nonerect penis of the bull, ram, and boar
sigmund flexure
the single male accessory reproductive gland that surrounds the pelvic urethra and sends many ducts into the urethra
prostate gland
the portion of the urethra located in the penis
penile urethra
the entrance into the vagina
vestibule
erectile tissue in the dog penis that swells after ejaculation
bulbous glandis
the penis muscle that pulls the penis of bulls, rams, and boars back into its nonerect S-shape
retractor muscle
a funnel-like enlargement at the ovarian end of the oviduct
infundibulum
the female gonad
ovaries
the portion of the urethra located in the pelvic canal
pelvic urethra
the cord that links the testes with the rest of the body, comprised of blood and lymphatic vessels, nerves, and the vas deferens
spermatic cord
the duct through which spermatozoa enter the epididymis
efferent duct
the sheath of skin that encloses the penis when it is not erect
prepuce
the hollow, muscular organ where pregnancy is maintained
uterus
part of the female vulva that contains erectile tissue and is covered by many sensory nerve endings
clitoris
the birth canal and the tube that receives the penis during breeding
vagina
the larger of the two penile erectile tissues
corpus cavernosum penis
the only externally visible part of the female reproductive tract
vulva
a bone that partially surrounds the penile urethra of a dog
os penis
the smooth muscle valve between the uterine body and the vagina
cervix
the microscopic tubules in the testes where spermatozoa are produced
seminiferous tubules
the sac of skin that houses the testes
scrotum
lips of the vulva
labia
fingerlike projections from the edge of the infundibulum on the oviduct that surround a follicle
fimbriae
the most caudal male accessory reproductive gland that secretes a mucus-like liquid that lubricates and clears the urethra
bulbourethral gland
the male gonads
testes
the muscle attached to the scrotum that allows the testes to be brought closer to or further away from the body to control their temperature
cremaster muscle
the multilayered, fluid-filled sac around the developing fetus that attaches to the uterine lining
placenta
where does fertilization take place
oviducts
the male breeding organ
penis
what muscle helps regulate scrotal temperature?
cremaster muscle
why is temperature regulation so important?
because the testicles need to remain cooler than the rest of the body
what male reproductive organ delivers sperm to the urethra?
vas deferens
what male connective tissue reproductive structure contains blood vessels, nerves, lymphatic vessels and the vas deferens?
spermatic cord, which goes through the inguinal ring of the abdomen
what is the name of the fibrous connective tissue, deep to the vaginal tunics that protects the testicle
tunica albuginea
what is the general name that refers to the suspensory ligament of the uterus?
broad ligament
where is the ovum fertilized?
oviducts
what is the name of the structure of the oviduct that catches the egg for delivery to the uterus?
infundibulum
two species that are induced ovulators?
cats and ferrets
what is the female gamete?
ova
endocrine glands
ductless glands that secrete tiny amounts of hormones directly into the bloodstream
endocrine system
slow reaction to stimuli & long duration of effects, travel through bloodstream
hormones
secreted directly into bloodstream & produce effects only when they bind to their specific receptors in or on cells
negative feedback
most common; activity is decreased by rising levels of hormone, once homeostasis is achieved the hormone production is stopped to prevent high levels
positive feedback
activity increased due to falling levels of a hormone; will continue increasing even though there is already a high amount
hypothalamus
controls activity of pituitary gland; blood vessels link anterior portion of pituitary; modified neurons secrete releasing & inhibiting factors
what hormones does the hypothalamus secrete?
ADH & oxytocin
how does the hypothalamus communicate with the anterior pituitary?
via bloodstream to send a signal to the affecter organ
how does the hypothalamus communicate with the posterior pituitary?
via nerve signals, telling it to store or release hormones
pituitary gland
aka hypophysis; master endocrine gland
adenohypophysis
anterior pituitary; rostral; makes hormones when stimulated
neurohypophysis
posterior pituitary; caudal; stores & release hormones made by the hypothalamus when needed
anterior pituitary hormones
TSH, FSH, ACTH, GH, Prolactin, LH, MSH
TSH
stimulates growth & development; causes thyroid gland to produce hormone; aids in metabolism
FSH
stimulates spermatogenesis in males; stimulates oogenesis in females & helps ovaries develop, mature & release eggs
fossa glandis
tip of the equine penis
GH
promotes body growth in young animals; helps regulate metabolism of proteins, lipids & carbohydrates in all body cells
prolactin
helps trigger & maintain lactation; level is highest when animal is lactating
LH
completes process of follicle development in ovary; stimulates male production of testosterone; works with FSH to complete process for embryo
MSH
associated with color changes in the skin
posterior pituitary gland hormones
ADH & oxytocin
ADH
helps prevent urination; if the hypothalamus notes dehydration, a more concentrated urine is produced
Diabetes insipidus
ADH deficiency; PU PD
oxytocin
causes constriction of the myometrium, the uterus muscle; aids in milk let down
thyroid gland
2 lobes on either side of the larynx; produces precursor hormone colloid & regular hormones T3, T4, & calcitonin
isthmus
connective tissue that connects the lobes of the thyroid gland
function of thyroid gland
regulates metabolic rate of all body cells; burns calories to generate heat; synthesizes cards & proteins & aids in the growth & development of animals in the central nervous system, muscle & bones
calcitonin
produced in parafollicular cells of the thyroid gland; prevents too much milk
parathyroid gland
small pale nodules in, on, or near the thyroid gland; produces PTH; helps maintain blood calcium homestasis
PTH
parathyroid hormone; exerts opposite effect of calcitonin; prevents low calcium levels
goiter
disorder of the thyroid gland in which precursors are constantly produced
adrenal gland
located at the cranial poles of the kidneys; produces mineralocorticoids, glucocorticoids, sex hormones; secretes epinephrine & norepinephrine
polyestrous interval
cycle year round if not pregnant; cattle and swine
seasonally polyestrous interval
cycle continuously at a certain time of the year; horses, sheep and cats
glucocorticoids
increases level of sugar
sex hormones
androgens for males, estrogens for females
adrenal gland medulla
develops from nervous tissue; secretes epinephrine & norepinephrine directly into bloodstream
cushings
too much corticoid production in the adrenal gland
pancreas
located near duodenum; islets of langerhans produce insulin, stores sugar & potassium
glucagon
alpha cells; exocrine & raises blood glucose levels & may be stored in the liver; pancreas produces glucagon when body has low blood sugar
insulin
beta cells; endocrine & lowers blood sugar
somatostatin
delta cells; inhibits both the alpha & beta cells
gonads
reproductive organs, testes & ovaries; stimulated by LH, promotes secondary sex characteristics
addison’s disease
low levels of cortisol production in the adrenal gland
metabolic waste products
products not needed by the body anymore, include potentially harmful substance that must be eliminated and can be harmful if accumulated
kidneys
located in the dorsal abdominal area; right kidney is more cranial than left
retroperitoneal
Between the peritoneum & the abdominal cavity
urinary system functions
Production of urine; maintain homeostasis through blood filtration, reabsorption & secretion; fluid base regulation; acid base balance regulation; production of hormones; blood pressure regulation
Nerve supply to the kidney
Sympathetic stimulation causes vasoconstriction of renal vessels; sympathetic portion of autonomic nervous system releases norepinephrine
Kidney hormones
ADH, aldosterone, erythropoietin, prostaglandins, & rentin
Renal capsule
Thick fibrous covering of the kidney
Hilus
Indented area where ureter, renal artery, renal vein & nerves enter & leave
Renal cortex
Outer portion of the kidney, reddish brown in color
Renal medulla
Surrounds renal pelvis; drains urine to calyces
Calyces
Direct urine into renal pelvis, from there urine moves into ureter
Renal pelvis
Urine collection chamber that forms beginning of ureter; not present in cow; lined with transitional epithelium for stretching
Mutilobar/multi pyramidal
Numerous medulla a facing the ureter; cows & pigs
Unipyramidal/ unilobar
Medullary pyramids fused as 1 structure to form a calyx that directs urine into renal pelvis
Nephron
Basic functional unit of the kidney
Afferent arterioles
Carry blood to renal corpuscle
Renal corpuscle
Located in the cortex, made up of the glomerulus & bowmen’s capsule
Glomerulus
Tuft of capillaries where filtration starts; forms glomerular filtrate
Bowmen’s capsule
Double walked capsule that surrounds glomerulus with visceral & parietal layers
Podocytes
Extensions that cover glomerular capillaries with a permeable layer to allow fluid & dissolved substances to pas through
Proximal convoluted tubule
Continuation of capsular space of bowmen’s capsule; longest part of nephron; reabsorption & secretion of tubular filtrate
Efferent arterioles
Carry blood out of renal corpuscles
Peritubular capillaries
O2 exchange to cells of nephron; reabsorption & secretion
Loop of henle
Continues from PCT, descends into medulla, makes a u turn & heads back into cortex; ascending wall becomes thicker again
Distal convoluted tubule
Continuation of ascending loop of henle; empties into collecting ducts
Collecting ducts
Hold urine; empty into renal pelvis; primary site of ADH action & regulation of K, Na & acid-base balance
Blood flow through the kidney
Renal artery ➡️ afferent arterioles ➡️ glomerulus capillaries ➡️ efferent arterioles ➡️ peritubular capillaries ➡️ renal vein
Renal artery
Branches off abdominal aorta & brings blood to the kidney
Renal vein
Takes purified blood from the kidney & brings it to the caudal vena cabs
Fenstrations
Windows in capillary endothelium
Urine volume regulation
Controlled by the action if ADH & aldosterone
Ureters
3 layers Outer fibrous Middle muscular Inner epithelial
Trigone
Oblique angle where ureters insert into the bladder
Urinary bladder
Where urine is stored as its produced
Detruser muscle
Smooth muscle of the urinary bladder that contracts to expel urine
Circulator sphincter muscle
Around the neck of the bladder to provide voluntary control over urination process
Control of urination
Urine accumulation Detruser muscle contraction Circulator sphincter muscle controlRelease of urine
Urethra
Continuation of the neck of the bladder
Urachus
Tube that runs from the fetal bladder to the umbilicus vein
Waste products include
Water, urea, salts &a other soluble waste products
what structure protects the birds legs when it lands?
synsacrum
when a bird rubs its beak on a rough surface to keep it clean, it is doing what?
feaking
what bones make up the pectoral girdle?
coracoids, clavicles & scapula
the part of the contour feather that contains barbs and barbules is
vane
what is the term used to identify the web of skin in the wing?
patagium
bumblefoot is caused by
claw neglect
Anterior glandular stomach of birds in which chemical digestion of proteins begins
proventriculus
Part of the respiratory system of the bird; there are nine in the system
air sacs
An essential muscle, along with the supracoracoideus muscle, that generates wing motion
pectoralis
A dilation of the esophagus in some species of birds that acts as a storage pouch for food
crop
Section of the avian oviduct that secretes albumin (the egg white) of the egg
magnum
The cavity located at the end of the digestive tract of birds that receives waste products from the intestinal, urinary, and genital tracts
cloaca
Muscular stomach in birds that grinds food into a digestible form
gizzard
Section of the avian oviduct that deposits the keratin shell membrane
isthmus
Enlargement of the trachea above the sternum in birds
syrinx
modifications to anatomy that enable flight
reduction in the number of bones; fused bones to make them stronger; reduced bone density; loss of internal bone matrix
axial skeleton
cervical, thoracic, lumbar, sacral and coccygeal
synsacrum
fusion of vertebrae; protect spine and legs when a bird lands
pygostyle
fusion of the most caudal coccygeal vertebrae; supports the tail feathers
keel
the sternum; acts as a shield; site of attachment for flight muscles; injection site
pectoral girdle
the shoulder; supports the wings and protects the chest; consists of the coracoids, scapulas, and the clavicles
coracoid
part of the pelvic girdle that protects the sternum
scapulas
protect the rib cage
clavicle
the wishbone; positioned outward to forward to keep the shoulders separated; protects the crop
humerus
where the wing muscles attachment site for wing muscles
appendicular skeleton
pelvic girdle and avian leg
pelvic girdle
supports/protects the legs; illium is fused to the synsacrum; ishium and pubis are fused to illium
avian leg
composed of femur, tibiotarsus, fibula and tarsometatarsus
coping
trimming or reshaping of beaks and nails
patagium
wing web skin; aids in flight
alula
first digit; originates from the wrist
metacarpal bones
join with fingers to help support primary flight feathers
pectoralis muscle
controls downstroke of wing; larger more superficial of the flight muscles
supracoracoideus muscle
deep wing muscle; controls upstroke of flying
layers of the eye
outermost fibrous tunic layer; middle layer is the uveal tunic; inner most layer is neural tunic
sclerotic ring
ring of small bones that protect the eye
feaking
when a bird rubs their beak on a rough surface to clean and maintain its shape
uropygial gland
one major skin gland that helps clean and waterproof feathers through preening
pterylae
feather tracts
apteria
bare areas of skin with no feathers
reminges
wing feathers
retrices
tail feathers
auriculars
surround ears
digestive anatomy
beak, mouth, esophagus (crop), stomach, liver, pancreas, small/large intestines and cloaca
proventriculus
glandular stomach that initiates chemical digestion
ventriculus
gizzard; muscular stomach that grinds coarse ingesta
crop
dilation of the esophagus where food is stored
cloaca
final structure of digestive system; 3 parts - coprodeum, urodeum, proctodeum
coprodeum
receives intestinal waste
urodeum
receives waste from the urogenital system
proctodeum
stores waste
vent
waste products are expelled through here
syrinx
voice box; dilation of the trachea
air sacs
9 in total, 4 pairs & 1 single interclavicular; maintain air volume, provide buoyancy & aid in thermoregulation
female reproductive system
left is functional, right is rudimentary
magnum
makes the egg white
isthmus
shell gland that forms the keratin shell membrane and exterior shell
uterus
produces calcium for the shell
cere
located at the base of the upper mandible
nictitating membrane
third eyelid
pecten
provides nutrition to the eye
choanae
connects the mouth to the nasal chambers
inferior umbilicous
tiny opening at the base of a feather where it inserts into the skin
superior umbilicous
where the webbed part of a feather begins
calamus
quill of a feather
rachis
main feather shaft
vane
flattened part of a feather that appears weblike, which have barbs and barbules in them
male gamete
sperm
female gamete
ova
gubernaculum
bands of connective tissue that attach testes in sctrotum
endocrine glands
ductless glands that secrete tiny amounts of hormones directly into the bloodstream
endocrine system
slow reaction to stimuli & long duration of effects, travel through bloodstream
hormones
secreted directly into bloodstream & produce effects only when they bind to their specific receptors in or on cells
negative feedback
most common; activity is decreased by rising levels of hormone, once homeostasis is achieved the hormone production is stopped to prevent high levels
positive feedback
activity increased due to falling levels of a hormone; will continue increasing even though there is already a high amount
hypothalamus
controls activity of pituitary gland; blood vessels link anterior portion of pituitary; modified neurons secrete releasing & inhibiting factors
what hormones does the hypothalamus secrete?
ADH & oxytocin
how does the hypothalamus communicate with the anterior pituitary?
via bloodstream to send a signal to the affecter organ
how does the hypothalamus communicate with the posterior pituitary?
via nerve signals, telling it to store or release hormones
pituitary gland
aka hypophysis; master endocrine gland
adenohypophysis
anterior pituitary; rostral; makes hormones when stimulated
neurohypophysis
posterior pituitary; caudal; stores & release hormones made by the hypothalamus when needed
anterior pituitary hormones
TSH, FSH, ACTH, GH, Prolactin, LH, MSH
TSH
stimulates growth & development; causes thyroid gland to produce hormone; aids in metabolism
FSH
stimulates spermatogenesis in males; stimulates oogenesis in females & helps ovaries develop, mature & release eggs
ACTH
stimulates growth & development of adrenal gland cortex; also the release of some of its hormones; can be release quickly as a result of stress
GH
promotes body growth in young animals; helps regulate metabolism of proteins, lipids & carbohydrates in all body cells
prolactin
helps trigger & maintain lactation; level is highest when animal is lactating
LH
completes process of follicle development in ovary; stimulates male production of testosterone; works with FSH to complete process for embryo
MSH
associated with color changes in the skin
posterior pituitary gland hormones
ADH & oxytocin
ADH
helps prevent urination; if the hypothalamus notes dehydration, a more concentrated urine is produced
Diabetes insipidus
ADH deficiency; PU PD
oxytocin
causes constriction of the myometrium, the uterus muscle; aids in milk let down
thyroid gland
2 lobes on either side of the larynx; produces precursor hormone colloid & regular hormones T3, T4, & calcitonin
isthmus
connective tissue that connects the lobes of the thyroid gland
function of thyroid gland
regulates metabolic rate of all body cells; burns calories to generate heat; synthesizes cards & proteins & aids in the growth & development of animals in the central nervous system, muscle & bones
calcitonin
produced in parafollicular cells of the thyroid gland; prevents too much milk
parathyroid gland
small pale nodules in, on, or near the thyroid gland; produces PTH; helps maintain blood calcium homestasis
PTH
parathyroid hormone; exerts opposite effect of calcitonin; prevents low calcium levels
goiter
disorder of the thyroid gland in which precursors are constantly produced
adrenal gland
located at the cranial poles of the kidneys; produces mineralocorticoids, glucocorticoids, sex hormones; secretes epinephrine & norepinephrine
adrenal gland cortex
develops from glandular tissue; produces mineralocorticods, glucocorticoids, & sex hormones
mineralocorticoids
regulates Na, K, Cl
glucocorticoids
increases level of sugar
sex hormones
androgens for males, estrogens for females
adrenal gland medulla
develops from nervous tissue; secretes epinephrine & norepinephrine directly into bloodstream
cushings
too much corticoid production in the adrenal gland
pancreas
located near duodenum; islets of langerhans produce insulin, stores sugar & potassium
glucagon
alpha cells; exocrine & raises blood glucose levels & may be stored in the liver; pancreas produces glucagon when body has low blood sugar
insulin
beta cells; endocrine & lowers blood sugar
somatostatin
delta cells; inhibits both the alpha & beta cells
gonads
reproductive organs, testes & ovaries; stimulated by LH, promotes secondary sex characteristics
addison’s disease
low levels of cortisol production in the adrenal gland
male gamete
sperm
female gamete
ova
gubernaculum
bands of connective tissue that attach testes in sctrotum
male sex hormones
androgens which are produced in the interstitial cells; testosterone is produced under the influence of LH
leydig cells
aka interstitial cells
gubernaculum
bands of connective tissue that attach testes in the scrotum
testicular artery
where temperature regulated blood passes in and out of
orchiectomy
castration
septa
divides each testis into tiny lobules that contain seminiferous tubules
sertoli cells
support developing sperm and shield them from the immune system
efferent ducts
house the seminiferous tubules
epididymis
sperm are stored here to mature; connect efferent ducts with vas deferens
vas deferens
muscular tube that connects the epididymis to the urethra
accessory reproductive glands
secretions from these glands make up the majority of semen; help the sperm survive through the acidic female reproductive tract
seminal vesicle
enter the pelvic urethra, not present in cats & dogs
2 bands of connective tissue that consist of the root of the penis
crura
corona glandis
glands of the equine penis that flare up to form a mushroom shape
urethral process
extends from the central depression of equine fossa glandis
fossa glandis
tip of the equine penis
broad ligaments
sheets of peritoneum that hang the ovaries, oviducts and uterus
mesovarium
suspensory ligament of the ovary
mesosalphinx
supports the oviduct
mesometrium
round ligament of the uterus
ovaries
produce hormones estrogen and progestins
outer uterine layer
perimetrium
middle uterine layer
myometrium
inner uterine later
endometrium
estrus
heat period
diffuse placenta
horse and pig placenta
cotyledonary placenta
ruminant placenta
zonary placenta
dog and cat placenta
discoid placenta
primates, rodents and rabbits
placentomes
sites where placenta and uterus attach in ruminants
caruncle
fleshy masses where the placenta attaches on the wall of the uterus in ruminants
estrous cycle
controlled by hormones FSH and LH
polyestrous
cycle year round if not pregnant; cattle and swine
seasonally polyestrous
cycl
diestrous interval
2 cycles per year; dogs
monoestrous interval
1 cycle per year; foxes and minks
proestrus stage
follicular development
estrus stage
sexual receptivity
metestrus stage
period of ovulation
diestrus stage
maintenance of corpus luteum if pregnant, reabsorption if not
anestrus stage
seasonal inactivity in seasonally polyestrous, diestrous and monestrous animals
