Exam 1 Flashcards
1
Q
Hormone
A
produced by endocrine glands
acts on cells, tissues, or organs
facilitates/inhibits a physiologic process
broader level-whole body
2
Q
endocrine gland
A
secretes within the body
usually into blood or lymph but there are some exceptions
endo=within
3
Q
exocrine gland
A
secretes externally
has ducts to carry molecules to the exterior (ex: sweat, urine, mucous, etc…)
4
Q
what purpose do hormones serve
A
integration purpose
5
Q
how long does a neural pathway take
A
seconds
6
Q
how long does an endocrine pathway
A
can range from minutes to hours and maybe even days
7
Q
neuro-endocrine system
A
full integration of the two systems (nervous and endocrine)
8
Q
examples of hormones regulating body functions
A
growth-growth hormone lactation-oxytocin estrous cycle-estradiol ovulation-luteinizing hormone parturition-oxytocin, relaxin
9
Q
basic structures in the reproductive endocrine system
A
brain (hypothalamus and pituitary gland)
repro tract (female=uterus, ovaries; male=penis, urethra, testis)
HORMONES CONNECT BRAIN AND REPRO TRACT
10
Q
three things to consider when looking at types of hormones
A
- site of production
- stimulatory or inhibitory
- structure (protein or lipid/small or large)
11
Q
differences between a protein and a lipid
A
a lipid can directly enter a cell through a bilayer. Lipid hormones, like steroids, have to be carried through on carrier proteins. Cannot be released as free floating molecules to get to the next location. EX: testosterone and estradiol
A protein needs help passing through the cell bilayer by using a receptor. Hydrophilic molecules that can be released as free floaters to get to their next location. EX: luteinizing hormone
12
Q
glycosylation
A
when a molecules is glycosylated it means sugars are added
glycos=sugar
glycosylated hormones increase the half-life in circulation. Happens with proteins. Sugars are added to the protein between the ER and the Golgi Apparatus to make the protein glycosylated. Happens within the cell that is producing the hormone
13
Q
why does it matter if hormones are large or small?
A
large tend to stay in circulation longer and have biological effects
small are easily degraded
14
Q
describe the location of the hypothalamus and the pituitary glands
A
they are very small and are in the part of the brain that is very protected
15
Q
describe the structure of the pituitary gland
A
it has two sections: the posterior pituitary and the anterior pituitary
posterior pituitary=made up of true neuroendocrine tissue. AKA neurohypophysis
anterior pituitary=made up of vascularized tissue which means it is rich in blood supply. It has a capillary plexus which is a closed capillary network. AKA adenohypophyis
located above the rook of the pharynx and is completely encased by bone (sphenoid bone) to protect it
16
Q
describe the structure of the hypothalamus
A
located above the pituitary gland
made up of many different areas. We will focus on three:
PON: Pre-Optic Nucleus. Nucleus=cluser of neurons within the hypothalamus. GnRH surge control center.
ARC: arcuate nucleus. Nucleus=cluster of neurons within the hypothalamus. GnRH tonic control center/
ME: Median Eminence. Region of hypothalamus where a lot of neurons and their axons converge just before they make their way to the pituitary gland. Has a capillary plexus
master neuroendocrine gland
17
Q
blood brain barrier
A
it prevents certain molecules from making their way from axons into the bloodstream or from the bloodstream into neural tissue (brain tissue)
prevention of moment starting in brain into bloodstream or vice versa
median eminence is one location where there is a lack of blood brain barrier. This is why when the neurons terminate the ME they can literally dump their contents into the bloodstream-which is what happens. GnRH dumps its contents into the bloodstream at the level of the median eminence
18
Q
functions of the hypothalamus include
A
appetite thirst body temperature vasomotor activity emotion use of body nutrient reserves activity of intestine sleep sexual behavior production and secretion of reproduction releasing hormone. Releasing hormones are going to find a target tissue and stimulate the secretion of something else.
19
Q
hypothalamic hormones
A
site of production=hypothalamus-GnRH
GnRH=gonadotropin releasing hormone. Action is to affect downstream hormones to release them.
GnRH=stimulatory
Growth inhibitory someone (somatostatin)=inhibitory
structure and size: short chain polypeptides (3-44 amino acids). Polypeptides=protein hormones. Small=shorter half life, won’t remain in circulation for long before destroyed
20
Q
why did pharmaceuticals create synthetic GnRH hormones
A
natural GnRH hormones have an easily degraded structure (at sites 5-6 and 10). The synthetic hormone fixes this problem and makes them less vulnerable to degradation. The synthetic GnRH are more potent and last longer and has stimulatory affects on ovulation
21
Q
follicle stimulating hormone
A
stimulates the ovary and testis
22
Q
luteinizing hormone
A
stimulates ovulation in the ovaries and steroid production in the ovary and testis
23
Q
Glycosylation of FSH and LH
A
FSH and LH makes sense tone glycosylated because they have to travel father to the ovary and testis and need to last in the body to reach and affect
24
Q
FSH and LH are heterodiemers. what does heterdiemer mean?
A
Hetero=two different kind of subunits (one is alpha and one is beta)
Diemers=two subunits combined
FSH and LH have the same alpha subunit but they differ in their beta subunits which gives them their specificity by targeting with receptors within the tissue to cause specific responses
25
how does GnRH travel to the anterior pituitary to release LH and FSH?
GnRh from the pre optic nuclei in the hypothalamus gets dumped into the blood supply at the median eminence through axons and makes its way to the anterior pituitary causing the release of LH and FSH by affecting the cells that release LH and FSH
26
gonadal steroids refer to
estrogen
progesterone
testosterone
27
importance of the superior hypophyseal artery
capillary plexus found in the median eminence
| coming from the general circulation and bringing oxygen and nutrients to this whole system
28
importance of the hypophyseal portal vessels
still have oxygenated blood and nutrient blood
this blood makes its way to the secondary capillary plexus
consists of enzymes (endopeptidases and carboxypeptidases) both have the net affect of degrading proteins that are in the blood supply
29
How do Oxytocin and ADH reach the posterior pituitary?
the cluster of neurons that provide hormones to the posterior pituitary are the supraoptic nuclei and the paraventricular nuclei. they travel all the way into the posterior pituitary and dump their contents (oxytocin and ADH) directly into the circulation via the capillary plexus
30
cholesterols synthesis to estradiol
once cholesterol enters the gonads it goes through a sequence of enzymatic modifications to give us either estrogen/progesterone/testosterone
Step 1: cell obtains cholesterol from circulation. The rate limiting step for a cell producing steroids is for the cholesterol to make its way from the cytoplasm of the cell into the mitochondria. The STAR (steroid acute regulatory protein) molecule is responsible for the rate-limiting step and bringing cholesterol from the cytoplasm into the mitochondria *key step for steroid synthesis*
Step 2: start of enzymatic changes. Notice you go from a 27-C cholesterol to a 21-C Pregnenolone. The side chain gets clipped off by the enzyme P450 side chain cleavage (P450scc).
Step 3: Thehis is the conversion of 21-C pregnenolone to 21-C progesterone. 3 beta hydroxy steroid dehydrogenase (3B-HSD) takes the three position hydroxyl group and pulls it off converting it to a veto group.
(Pulling the hydrogen off is performed by the 3B-HSD)
Step 4: 21-C progesterone to 19-C testosterone. The steroids here are not important but know that this is a step.
Step 5: the 19-C testosterone is converted to an 18-C estradiol. The P450 aromatase enzyme (P450arom) takes the testosterone ring resulting in an aromatic ring to form in the spot
31
what steps of cholesterol steroid synthesis occur in the mitochondria?
cholesterol and pregnenolone
| enzyme P450scc present here
32
what steps of cholesterol steroid synthesis occur in the smooth ER?
Progesterone, testosterone, and estradiol;
| enzymes 3B-HSD and P450arom are present here
33
prostaglandins
another type of lipid derived hormone
all cells have the capability to create prostaglandins if they have the proper enzymes because they can make it within their membrane
PGE2 and PGF2
34
net effects of PGE2
vasodilation
maintain CL
ovulation
implantation
35
net effects of PGF2
```
vasoconstriction
CL regression
ovulation
parturition
sperm transport
```
36
protein hormones
hydrophilic
when they reach a target it needs to interact with a receptor on the cell-surface in order to have a downstream effect within the cell
the outer portion of receptor has sugars added onto it which react with the sugars on the glycoprotein hormone (LH/FSH) and when they interact they perform specificity and downstream effects for the receptor
37
broad ligament
connective tissue sheet
massive structure
supports and suspend the reproductive tract-suspended from the dorsal wall (back of animal) and reproductive tract hangs from this ligament
38
mesometrium
supports uterus
39
mesosalpinx
supports oviduct
40
mesovarium
supports ovary
41
ovary
primary sex organ
(bovine ovary=about 5-6 cm large)
hormonal=produce steroid and protein hormones
steroid: estrogen and progesterone
protein: anti-mullerian hormone, inhibit, activin
gametogenic: oocyte=egg=ova
42
follicles
found on ovaries
blister like projections
hormones secrete estrogen
houses the oocyte/egg and it is released from follicle during ovulation
43
corpus luteum
"yellow body"
lutein molecule gives it a yellowish tint
secretes the steroid progesterone which is responsible for maintaining pregnancy if an animal becomes pregnant
44
medulla
innermost region of the ovary
| where there is nerve and blood supply
45
cortex
outermost region of the ovary
| where follicles are found in various stages of growth and where the corpus lute is found
46
hilus
portion that connects to the mesovarium. blood and nerve supply goes through this to get to the ovary
47
tunica albuginea
small layer made up of connective tissue
48
germinal epithelium
a single layer of cell surrounding the outside of the ovary
| 85% of ovarian cancers in humans are in the germinal epithelium due to defects
49
primordial follicle
flattened cells surrounding oocyte
| egg is small. single layer of cells surrounding eggs becomes flattened. granulosa cells.
50
primary follicle
larger oocyte, cuboidal granulose cells
size of egg has grown and the structure of the cells surrounding them becomes more a cuboidal cell structure
granulosa cells
51
secondary follicle
several layers of granulose cells
| size of egg hasn't really changed much but there are several layers of granulose cells surrounding the egg
52
tertiary follicle
fluid filled cavity (antrum)
granulose cells are present and theca cell layers start to form around the follicle
-theca interna: vascular cells that are closest to the basement membrane (bm=avascular)
-theca externa: larger blood vessels, lymphatic system, nerves
53
cumulus oophorus
cumulus oophorus cells join the egg while it is released from the ovary. helps to control maturation of the cell and prepare it for fertilization
54
lumen
innermost space of the reproductive tract
55
mucosa
first layer of cells lining the reproductive tract
56
submucosa
lymphatics, blood supply, etc...found here. directly below the mucosa
57
smooth muscle layers
the circular smooth muscle layer is overlaid by a longitudinal smooth muscle layer
smooth muscle layers are oriented criss cross to each other (muscularis). this is because of peristalsis which is directional movement to secrete and expel things. The smooth muscle is involuntary and more resistant to fatigue
58
serosa
has secretions to it
| allows things to slide and slip against each other
59
function of the oviduct
gamete transportation:
-sperm: making its way toward the ovary
-oocyte: moving down away from ovary
-site of fertilization: captures the sperm and provides a space for the egg to reside until fertilized
supports early embryo development: 1-2-4-8-16 cell divisions right after fertilization occurs here until it gets large enough to travel to the uterus
transport of embryo to uterus
60
infundibulum
funnel like structure that is part of the oviduct
61
fimbria
fingerlike projections from the infundibulum that help massage the egg and guide it to the ostium
also secrete mucus to help move it down the path along with the overlying smooth muscle layers to help sperm and egg meet
62
ostium
opening of the infundibulum
63
ampulla
middle section of oviduct
64
ampullary isthmus junction
site of fertilization!
65
isthmus
last portion of oviduct
66
oviduct histology
mucosa: ciliated columnar and conciliated columnar
67
functions of the uterus
muscle contractions: transport sperm and expel fetus and placenta
absorption and phagocytosis
prepares sperm for fertilization: capacitation
provides environment for embryo and fetal growth
hormone production: prostaglandin F2alpha production-uterine contraction and regression of corpus luteum
68
function of the cervix
```
transport sperm
barrier to sperm (species dependent)
reservoir for sperm
blocking bacterial invasion during pregnancy
birth canal
```
69
functions of the vagina
copulatory organ
glands secrete lubrication
birth canal
glands secrete pheromones
70
uterine body vs horn size
depending on species that is pregnant and number of their offspring will determine the length of their horns
- litter bearing species have longer horns and smaller body
- species that typically have one offspring have a more developed uterine body and underdeveloped horns
71
parts of the uterus
endometrium
myometrium
perimetrium
72
endometrium
innermost segment of the uterus
endo=within
caruncles: points of attachment to the placenta of the fetus (blood exchange occurs, nutrient exchange occurs, etc...)
73
myometrium
middle muscular layer, smooth muscle cells
| myo=muscular layer
74
perimetrium
outside layer of the uterus
| outermost surface of the uterus
75
uterine anatomy
layers can be fairly seen on histology cells
myometrium: some cells will look like circles and some will look longitudinal due to the criss cross matching of the smooth muscles
76
functions of the cervix
```
transport sperm
berries to sperm (species dependent)
reservoir for sperm
blocking bacterial invasion during pregnancy
birth canal
```
77
cow cervix!
internal cervical Os: opening between uterine body and cervix
cervix is composed of thick connective tissue and smooth muscle
cow has 4-5 annular rings:
-cartilage rings that are 3D structures that form barriers due to them being there
-difficult for AI
mucus is secreted near the time of breeding and ovulation
-secretion type/consistency changes
--more liquid around ovulation and more viscous away from ovulation
external cervical Os: opening at the exterior of the cervix that leads to the vagina
-fornix: blind pocket that surround the external Os
78
functions of the vagina
copulatory organ: where the penis resides during the process of ejaculation
glands secrete lubrication
birth canal (once cervix dilates)
glands secrete pheromones
79
ovarian differences
cow an sow ovaries: follicles (blister like structures that form to produce/release an egg for ovulation) are obvious and can make their way to the cervix
cow: corpus lute
-size of follicles on ovary: 15-20 mm
-size of corpus lute: 20-30 mm
sow: corpora lutea
cow, sow, ewe, human: cortex on outside and ovulation occurs on the surface
mare: there are no corpora lutea/follicles seen on the surface because it is a totally different structure in terms of how it forms and functions
-inversion of cortex and medulla
-ovulation at the ovulation fossa
-size of follicles on ovary: 50-60 mm
-size of corpus lute: 40-50 mm
80
bicornuate species
bicornuate=2 horns, fused=1 uterine body, 1 cervix, 1 vagina
ewe: smaller uterine horns
cow: not litter bearing but fairly long and developed
sow: litter bearing-large uterine horns that have folds and are very developed and long
mare: uterine body more prominent. small uterine horns-not very developed or long.
bitch: small uterine body and long uterine horns
queen: small uterine body and long uterine horns
81
simplex
no horns, fused body
woman: large uterine body
no uterine horns
82
duplex
2 separate horns
opossum: 2 vaginas, 2 uterine horns, 2 cervixes
rabbit: 2 uterine horns, 2 cervixes, 1 vagina
mouse: 2 uterine horns, 2 cervixes, 1 vagina
83
vagina anatomy
cervix->fornix->anterior vagina (columnar epithelium-single layer of columnar epithelium that secrete and absorb)->vulva vaginal sphincter (separates the two compartments, aka hymen)->posterior vagina (stratified squamous epithelium-helps protect due to friction/abrasion during sex)
84
avian female anatomy
as they develop the right side of the reproductive tract will regress while the left side develops-unknown why this happens
the oviduct is prominently developed in chickens: infundibulum (catches ovaries), magnum (the additional layers that make up the egg get added on here: albumin, some parts of the shell membrane. Also where fertilization occurs), isthmus (holds the egg here for a short period of time)
the uterus is where the shell is added to the egg AKA: shell gland
cloaca is where both the vagina and intestines becomes one structure: release of egg and release of feces
follicles don't have anything surrounding them: you can tell the order when each follicle will make its way into the infundibulum by the size of the follicles-largest follicle goes first and is ovulated
85
how do follicles grow
folliculogenesis
86
folliculogenesis
preantral phase largely gonadotropin (FSH, LH) independent
form primary follicle onward, increasingly gonadotropin dependent (FSH stimulates granulose; LH stimulates theca)
theca (vascular) and granulose (avascular) layers separated by a basement membrane
oogonia are present in fetal ovaries and at birth the oogonia become primordial follicles
the activation of primordial follicles causes them to turn into primary follicles. these early stages are called prenatal phases and occurs independently of gonadotropin secretions-FSH or LH stimulation
primary to secondary follicles=unclear if there are gonadotropin stimulation this is the last portion of the prenatal phase
secondary to tertiary and tertiary to preovulatory follicles are dependent on gonadotropin secretions-FSH stimulation is needed for granulose cells and LH is needed to simulate theca cells
87
2-cell 2-gonadotropin mechanism of steroidogenesis
theca cells respond to LH and that response results in an increase in androgens by the cAMP mechanism. The androgens produced by theca cells can make their way across the basement membrane and become substrates for steroid production within the granulose cells. Granulose cells have receptors for FSH and get stimulated by FSH, a reaction occurs, and they stimulate enzymes that convert the androgens to estradiol (cholesterol precursor-->estrogen in bloodstream)
88
wave like pattern of follicle development
follicular waves: astral follicles in cattle develop in a wave-like pattern with the first wave starting a few days after estrus and the second wave beginning on days 12-14
periodic waves of astral follicle growth may occur in 3 wave patterns or 2 wave patterns
-waves are characterized by growth of astral follicles
-as long as the corpus lute is present and large and functional there will be a periodic recurrence of waves of follicles emerging and going through artesian until the corpus lute undergoes regression. As the size of the corpus lute starts to diminish then the dominant follicle of the wave that's closest to the regression of the corpus lute will eventually ovulate
dominant follicle emerges from each wave
waves continue until CL regresses
dominant follicle present at luteolysis comes preovulatory follicle
species with follicular waves: bos indicus, cattle, goats, llamas, dromedary camel, musk oxen, cervids, bison
89
role of FSH on wave initiation
surge of FSH that precede when the follicle of the cohort will be stimulated and recruited to go ahead and start their growth
90
follicle selection
the FSH follicle coupling hypothesis-all follicles are capable of becoming a dominant follicle
91
functional coupling between FSH and follicles
surge in FSH occurring at a time that is slightly ahead of seeing follicles recruited and start to grow
increase in FSH circulating through the body and the FSH target granulose cells within the follicles which leads to an increase in steroid production and cause them to mitotically divide and grow
once that occurs FSH starts to decrease because of the inhibit and estradiol suppressions from the granulose cells
the FSH continues to decrease and reaches the basement level-the number of receptors on the granulose cells have increased enough so the dominant follicle still remains sensitive to low levels of FSH; however, that is not the case for the subordinate follicles causing them to undergo atresia
92
anti mullein hormone
expressed and secreted by granulose cells of follicles and have effects on follicle activation and growth
-negatively regulates follicle activation and growth
locally AMH: (secreted by primary and secondary follicles) inhibits further activation of primordial follicles into that primary follicle pool
systemically AMH: affect hypothalamus and pituitary by decreased FSH secretion which affects the movement of secondary to tertiary follicles and so forth
high levels of AMH: means they probably have a large number of follicles which indicates greater fertility
93
luteinization
morphological and functional changes that granulose and theca cells undergo forming a corpus lute
characterized by...rapid cellular proliferation, differentiation, angiogenesis-establishment of blood supply in the tissue so that it can carry the large amounts of progesterone being produced to the other parts of the body
94
what happens to the CL while it is doubling in size and cell number every 60 hours during luteinization
the granulose cells of the ovulatory follicle undergo hypertrophy so they get larger in size but not number-large luteal cells
the theca cells of the follicle undergo some hypertrophy but they also increase in number (hyperplasia)-small luteal cells
the endothelial cells that make up the vasculature of the tissue are reestablished (angiogenesis=rapid proliferation of the endothelial cells) as the corpus lute is forming
95
luteotropism
characterized by arrested cellular proliferation (no more cells rapidly dividing at this time), progesterone secretion, high metabolic rate
96
luteolysis
destruction of corpus lute
occurs around days 15-17 an induced by PGF
process triggering CL regression
occurs at the end of luteal phase
characterized by reduced P4 (both LLCs and SLCs will reduce their progesterone secretion which is a huge sign that luteolysis is occurring), increased oxytocin (source of oxytocin=LLC), increased PGF2alpha (from uterus) which is transported to the ipsilateral ovary via the countercurrent exchange mechanism
decreased blood flow to CL (PGF=vasoconstrictor)
cellular response (apoptosis-programmed death of cells- and progesterone synthesis-declines)
immune response (lymphocytes accumulate and macrophages accumulate/phagocytosis)
97
follicular phase
when the follicle is recruiting
- progesterone declines as LC regresses
- estradiol increases as follicles get closer to ovulating
- FSH is stimulating follicles to go
- LH drastically increases (SURGE) that causes it to go from pre ovulation to rupturing open and ovulating
98
luteal phase
period of time when the corpus lute forms which lasts until the CL regresses
ranges from 15-16 days in cows
99
estrus
sexually receptive in heat
100
estrous
the cycle/period
101
polyestrus
multiple heats
queen, cow, sow
look at relatie E2-as they grow to the point of ovulation it results in a huge increase in E2 production
102
seasonally polyestrus
short day breeders: fall
-ewe, doe, elk, nanny=shorter gestation (5/6 months)-warmer and optimal conditions for birth in the wild
long day breeders: spring
-mare=roughly 11 month gestation-pastures are full, warmer temperatures, optimal conditions in wild to foal
look at relative E2 as they grow to the point of ovulation it results in a huge increase in E2 production
103
monoestrus
typically one heat
dog, wolf, bear, fox
look at relative E2 as they grow to the point of ovulation it results in a huge increase in E2 production
104
cow reproductive cycle
length of estrous cycle: 21 days polyestrus
length of estrus: 18 hour
ovulation: 11 hours after end of estrus
length of pregnancy: 282 days
105
ewe reproductive cycle
length of estrous cycle: 17 days seasonal (fall)
length of estrus: 29 hour
ovulation: near end estrus
length of pregnancy: 148 days
106
sow reproductive cycle
length of estrous cycle: 21 days polyestrus
length of estrus: 48-72 hours
ovulation: 35-45 hour after start of estrus
length of pregnancy: 115 days
107
mare reproductive cycle
length of estrous cycle: 21 days seasonal (spring)
length of estrus: 4-8 days
ovulation: 3-6 days of estrus (1-2 days before end of estrus)
length of pregnancy: 335 days
108
bitch reproductive cycle
length of estrous cycle: 6 months
length of estrus: 9 days
ovulation: 4-24 days after start of estrus
length of pregnancy: 63 days
109
queen
length of estrous cycle: 17 days
length of estrus: 9 days
ovulation: induced
length of pregnancy: 63 days
110
anestrus
lack of estrus/lack of heat
| insufficient GnRH is the underlying cause of anestrus bc GnRH is the master control center
111
causes of anestrus
```
season-long day or short day breeding
pregnancy
presence of offspring-suckling phenomenon
pathology
stress
nutrition
```
112
gestational anestrus
progesterone during pregnancy
- P4 has negative feedback on GnRH
- -placenta and corpus lute secrete progesterone which inhibits GnRH secretion (which also shuts down LH and FSH secretion)
- after parturition anestrus continues
- -carryover of progesterone during pregnancy
- -hypothalamus: lacks estradiol positive feedback
- allows time for uterine involution
- -uterus recovery is very important
113
seasonal anestrous
just like entering puberty
timed for optimal birth (spring)
controlled by photoperiod and melatonin from pineal gland
long day (mare) vs short day (ewe)
-in mare: role of melatonin unclear
-in ewe: more dark-more melatonin-more GnRH
114
lactational anestrus
suckling effect on LH
the suckling in the first several weeks causes the blood LH levels to be low which relates to decreased GnRH
about 6-7 weeks after calving (when the calves are weaned) there is a large surge in LH in the blood which is related to the increased levels of GnRH
115
nutritional anestrus
if an animal doesn't have sufficient energetic capacity from the standpoint of its nutrient status it will suppress the GnRH secretion and cause the animal to go into anestrus
116
pathologic conditions of anestrus
stress (cortisol suppresses ovulatory LH surge)
pathology: cystic ovary (common in dairy cow)
- follicular cysts (E2)
- luteal cysts (P4)
- -causes lower GnRH
