1
Q
nervous system control of body functioning
A
uses electrical impulses (neurotransmitters)
responds rapidly, response lasts milliseconds
only stimulates excitable tissue (muscle and glands)
2
Q
endocrine system control of body functioning
A
uses chemical messengers through the bloodstream (hormones), lag time before response, slower to adapt but lasts longer
stimulates target cells, changes the metabolic activity of the cell
3
Q
exocrine glands
A
use ducts
-secretions!! (saliva, sweat, oils, etc)
-primarily works in digestive system (ex. pancreas)
4
Q
endocrine glands
A
ductless
-secrete HORMONES
-highly vascularized glands
-chemical messengers travel through bloodstream
5
Q
what galnd has both exocrine and endocrine functions?
A
the pancreas
-digestive function
6
Q
what is the neuroendocrine link?
A
specific parts of the body have a strong connection between the nervous and endocrine system
-linked by the HYPOTHALAMUS
-hypothalamus and pituitary gland (master gland) are linked via infundibulum
7
Q
how does the neuroendocrine link work?
A
signals from the hypothalamus activate the pituitary gland to release a hormone which goes into the bloodstream and affects another part of the body (long distance)
8
Q
hormones
A
long distance chemical messengers that are produced in one part of the body and affect another part of the body
-does not affect the cell that produced the chemical!!!
9
Q
autocrines
A
secretions prodiced by a cell that affect the activity of that cel
-self-regulating
-does not affect neighboring cells!!
10
Q
paracrines
A
local signaling molecules that are secreted by a cell but only affect neighboring cells
-does not affect the cell that produced it!!!
11
Q
pheromones
A
chemicals secreted by one organism that affect the activity of a different organism
- sweat is sexually attractive, fear
12
Q
amino acid based, non-steroid, peptide-based hormones
A
majority of hormones that are derived from amino acids
-water soluble so they are easy to transport in bloodstream but need a receptor on outside of cell to pass through plasma membrane
13
Q
steroid hormones
A
derived from cholesterol, lipid soluble
-can pass across plasma membrane but need receptor INSIDE the cell to keep them from leaving
-do not pass through bloodstream easily
-ONLY produced by gonads & adrenal cortex
14
Q
eicosanoids
A
biologically active lipids (not true hormones)
-have localized effects
15
Q
types of eicosanoids?
A
-prostaglandins (multiple effects in cells, ex. is in menstrual cycle)
-leukotrines (inflammatory response and immune system function)
16
Q
target cells
A
any cell that has the receptor for a hormone
-hormones changes activity of this cell once binded to receptor
17
Q
effects of target cells
A
- open or close ion channels to change permeability of cell and change membrane potential
- stimulate protein synthesis by activating DNA directly
- activate or deactivate enzymes by turning existing proteins on or off
- promote secretions by stimulating exocytosis
- stimulate mitosis
18
Q
amino acid based hormone activation
A
indirect activation- binds to receptor and activates a protein on the inside of the cell to change the activity of cell
19
Q
steroid based hormone activation
A
direct by diffusion across the lipid bilayer and binding to receptor in the nucleus
20
Q
steroid action
A
- hormones secreted by an endocrine gland
- travels through the bloodstream to a target cell
- hormone difuses through the plasma membrane of the target cell
- binds with an intracellular receptor
- activated complex acts as a primer and binds to a specific receptor protein on DNA (different steroid activates different genes and cause different proteins to be produced)
- transcription is initiated which gives us mRNA
- mRNA leaves nucleus and goes to cytoplasm where it binds to a ribosome and is translated.
- new protein is produced (enzyme, structural protein, or export protein)
21
Q
Cyclic AMP non-steroid action
A
- hormone is secreted by an endocrine gland and travels through the bloodstream by a target cell
- hormone will bind to a specific receptor on the outside surface of the cell which modifies it
- the modified receptor binds with G protein to activate it and the G protein activates an enzyme called adenylate cyclase
- adenylate cyclase generates cAMP from ATP and cAMP becomes the secondary messenger which then stimulates protein kinases
- protein kinase reactions cause existing proteins to be phosphorylated which will either activate or deactivate the proteins
- phosphodiesterase degrades cAMP and shuts the cycle off
22
Q
PIP Calcium non-steroid action
A
- hormone is secreted by an endocrine gland and travels through the bloodstream to a target cell which binds to a receptor.
- modified receptor binds with a G protein and the G protein is activated.
- The activated G protein activates phospholipidase and it splits PIP2 into DAG and IP3.
- DAG activates protein kinase which causes phosphorylation of existing proteins.
- IP3 triggers release of calcium from endoplasmic reticulum and calcium acts as an additional messenger, catalyzing additional reactions in the body
23
Q
What is the only peptide-based hormone that functions as a steroid?
A
Thyroid hormone
24
Q
factors affecting hormone action
A
-hormone level in bloodstream
-# of receptors in or on target cells
-receptor affinity
25
hormone levels in the bloodstream
the more hormone in the bloodstream, the greater the activity
26
number of receptors in or on target cells
the more receptors we have, the greater the activity
27
receptor affinity
if a cell has strong affinity, it can be picked up from far away
the higher the affinity, the greater the activity
28
up regulation
continued exposure to a hormone results in more receptors for that so cells become more active
-stress causes a hormone to be produced so the cell will respond by increasing response to get back to homeostasis and the increased effect increases the receptors
29
down regulation
the continued release of a hormone decreases the number of receptors for that home
-increased hormone level DECREASES the effects of that hormone
30
permissiveness
one hormone requires a second hormone to be present in order to exert its fullest effect
Ex. thyroid hormone and sex maturation
31
synergism
two or more hormones produce the same effect and their combined effect is stronger
Ex. glucagon and epinephrine both increase blood glucose, they work stronger together
32
antagonism
two hormones work in opposition to one another to create feedback systems
Ex. glucagon and insulin raise and lower blood pressure
33
humoral mechanism for endocrine grand stimulation
changes in levels of something in the bloodstream or extracellular fluid that causes a gland to start functioning
34
neural mechanism for endocrine gland stimulation
nerve fibers stimulate and directly synapse with an endocrine gland and the neurotransmitter released activates the gland to secrete a hormone
35
hormonal mechanism for endocrine gland stimulation
an endocrine gland is activated by a hormone produced by a different endocrine gland
36
tropic hormone
a hormone whose target cell is another endocrine gland
37
pituitary gland
hypophysis
38
infundibulum
a stalk that extends off the hypothalamus
attaches the pituitary gland to the hypothalamus
39
thyroid
surrounds the trachea
40
parathyroid
embedded within the posterior thyroid
41
adrenal
on top of the kidneys
42
pancreas
in the abdominal cavity
43
gonads
testes in male and ovaries in female
44
pineal
in the brain
45
thymus
deep to sternum (not very active in adults
46
posterior pituitary- neurohypophysis
composed of neural tissue which is an outgrowth of the hypothalamus, extends off the infundibulum
- DOES NOT PRODUCE HORMONES -> only stores and releases hormones
47
anterior pituitary- adenohypophysis
composed of glandular tissue which is an out-pocketing of the oral cavity (Rathke's pouch pit)
-DOES PRODUCE HORMONES
48
connection between anterior and posterior pituitary
visceral connection
49
hormones secreted by posterior pituitary
1. oxytocin
2. antidiuretic hormone (ADH)
50
oxytocin
"cuddle hormone"
-functions with smooth muscle contractions (in childbirth, contracts the uterine muscles)
-involved with milk ejection during nursing
-functions as an amnesiac
-works through positive feedback
51
antidiuretic hormone (ADH)
regulates water balance by targeting the kidney tubules and causing them to reabsorb more water into the body
-prevents urine formation
-alcohol inhibits ADH (why you have to pee a lot when you're drunk)
52
hormones secreted by the anterior pituitary
1. growth hormone (GH)
2. thyroid-stimulating hormone (TSH)
3. adrenocorticotropic hormone (ACTH)
4. gonadotropins (Follicle stimulating hormone- FSH & Luteinizing hormone- LH)
5. prolactin (PRL)
6. pro-opiomelanocortin (POMC)
53
growth hormone actions
-stimulates cell growth and division, protein synthesis, fat metabolism, and glucose conservation
-growth of bones and muscle
54
pituitary dwarfism
deficiency in GH in children
-children small in size
55
Giantism
excess GH in children
-overall large in size
56
Acromegaly
normal levels of GH as a child, but it increases as an adult
-large hands, feet, and face
Ex. Abe Lincoln
57
GH cascade
1. Hypothalamus secretes GHRH and it affects somatotrope cells of the anterior pituitary and they begin GH synthesis.
2. GH gets into the bloodstream and has both direct and indirect effects on target tissues.
3. Increased amounts of circulating GH triggers production of growth hormone inhibiting hormone (somatostatin) which shuts off GHRH in order to stop production of GH
58
direct actions of growth hormone
-increase blood levels of fatty acids by taking fats from fat stores and putting them into the bloodstream
-stop glucose uptake and metabolism by leaving glucose in the bloodstream so it can go to active cells
-encourages breakdown of glycogen from the liver and release of gluocse into the bloodstream to increase amount of glucose available for energy
59
diabetogenic effect
breaking down of glycogen to release glucose
-direct action of growth hormone
60
indirect actions of growth hormone
operates through insulin-like growth hormones (IGFs):
-growth hormone stimulates the liver to produce IGFs
-IGFs stimulate uptake of amino acids from blood into cellular proteins
-stimulates uptake of sulfur into background matrix of cartilage
61
thyroid stimulation hormone (TSH)
also known as thyrotropin
stimulates the development and secretion of the thyroid gland
62
TSH cascade
1. hypothalamus secretes thyroid releasing hormone (TRH) which causes thryotropic cells of the anterior pituitary to produce TSH.
2. TSH activates the pituitary gland,
4. Increased levels of TSH inhibit the pituitary gland and hypothalamus to shut off TRH and produce GHIH (growth hormone inhibiting hormone- somatostatin)
63
adrenocorticotropic hormone (ACTH)
stimulates the adrenal cortex to release corticosteroid hormones
-mostly glucocorticoids (aldosterone) which are involved with resisting stress
64
ACTH cascade
1. The hypothalamus secretes corticotropin releasing hormone (CRH) which stimulates the corticotrope cells to release ACTH
2. ACTH stimulates the adrenal cortex to release glucocorticoids
3. Increased levels of glucocorticoids stop CHR and ACTH secretion stops.
65
what stressors promote CRH release?
fever, hypoglycemia
66
gonadotropins
regulate functions of the gonads
follicle stimulating hormone (FSH) and Luteinizing hormone (LH)
67
FSH
stimulates gamete production
-eggs and sperm
68
LH
promotes production of gonadal hormones
69
male gonadotropins
-LH stimulates interstitial cells of the testes to produce testosterone which gives males secondary sex characteristics
-FSH stimulates sperm production
70
female gonadotropins
born with all eggs
-FSH stimulates ovum production
-LH triggers ovulation and promotes synthesis of ovarian hormones which lead to secondary sex characteristics
-FSH and LH regulate maturation of eggs which are kept in follicles in the ovaries
71
gonadotropin cascade
1. at puberty, the hypothalamus secretes GnRH and this stimulates the gonadotrope cells f the anterior pituitary to secrete FSH and LH
2. gonadotropins cause gonads to mature and begin producing their own hormones
3. the increased levels of gonad hormones suppress FSH and LH by suppressing GnIH
72
prolactin
stimulates milk production by the mammary glands in the breasts
may enhance testosterone production in males
73
prolactin cascade during cycle
1. high estrogen levels stimulate release of PRH from the hypothalamus and this stimulates lactotropes of the anterior pituitary to secrete prolactin by suppressing PIH production.
2. Prolactin production is brief during ovarian hormone cycling (why your breasts get tender) but decreased estrogen at the end of cycle stimulates production of PIH from the hypothalamus.
3. Prolactin production stops when PIH is produced.
74
Prolactin cascade during pregnancy
1. HIgh estrogen levels turn off PIH and prolactin is triggers by PRL at the end of pregnancy. Milk starts to be produced.
2. Baby suckling maintains PRL production
3. Lack of suckling and return of normal hormone cycle brings about PIH production, and lack of prolactin stops milk production.
75
what is the largest pure endocrine gland in the body
thyroid gland
76
histological composition of thyroid gland
composed of follicles made up of epithelial cells called follicular cells and parafollicular cells
77
what do follicular cells produce
thyroglobulin- a protein that becomes an amino-acid based hormone
78
why is the thyroid gland unique
it both stores and secretes
-thyroglobulin is stored within the follicle as colloid
79
what makes up thyroid hormone
thyroglobulin + iodine (from our diet)
80
what do parafollicular cells produced
calcitonin- which is immediately secreted, it is not stored
81
what cells do not have receptors for thyroid hormone
brain
spleen
testes
uterus
thyroid
82
functions of TH
-increase basal metabolic rate and heat production through calorigenic effect (breakdown of glucose to generate heat and produce ATP
-maintains blood pressure by causing the production of aditional adrenergic receptors that are on teh surface of blood vessels and cause them to constrict
-regulates tissue growth and development
-maturation of reproductive organs
83
synthesis of TH
1. anterior pituitary secretes TSH and this travels to the thyroid gland via blood vessels which triggers the production of thyroglobulin by follicular cells.
2. Thyroglobulin is transported into the follicle and gets stored there while channels open to take in iodine and store it in the colloid.
3. Thyroglobulin is iodized to form T1 and T2 and they combine to form T3 and T4
4. T3 and T4 come out of the colloid and back into the follicle cells and are packaged into vesicles for exocytosis. Lysozomal enzymes free T3 and T4 into the bloodstream almost every organ in the body is affected.
84
why is the thyroid unique?
it can store the hormones that it produces.
85
Diurnal cycle
the thyroid can store its hormones for 2-3 months
-stored in the extracellular colloid
*TSH peaks before sleep and remains high at night (why college students get less sleep and gain weight)
86
TH feedback
-Increasing blood levels of T4 inhibit TSH production while low levels stimulate it
-Increased in body energy needs stimulates release of TRH (need is detected by hypothalamus -> TRH -> TSH)
-GHIH shuts off production of TH
87
which hormone is amino-acid based but acts like a steroid
Thyroid hormone
-T4 and T3 bind to transport proteins and are delivered to target cells, then they bind to intracellular receptors, DNA is activated and transcription results in new proteins
88
calcitolin
produced by parafollicular cells
- lowers blood calcium levels
- most important during rapid periods of skeleton growth and reformation (mainly during childhood and puberty)
89
actions of calcitonin
inhibits osteoclast activity (stops breakdown of bone)
stimulates calcium uptake and deposition into bone
90
calcitonin feedback
high calcium levels are humoral stimuli for increasing activity of C cells while low levels of calcium in the blood inhibits C cell activity
91
parathyroid gland
imbedded in the posterior portion of the thyroid gland (usually 4, sometimes 5, rarely there are 3)
92
histological composition of parathyroid gland
has two types of glandular cells
-oxyphil cells
-chief cells- secrete parathyroid hormone (PTH)
93
parathyroid hormone importance
most important hormone for controlling blood calcium levels in ADULTS
-antagonist to calcitonin: PTH increases blood calcium levels
-low levels of calcium have a humoral affect which activates chief cells to produce PTH
94
PTH actions
-stimulates osteoclasts to break down bone and release calcium into the bloodstream
-affects the kidneys by enhancing their reabsorption of calcium
-stimulates the intestines to absorb more calcium out of the food we've eaten
-promotes kidneys to convert viatmin D into its active form, calcitriol (D3), which helps us absorb calcium
95
adrenal glands
paired glands located on top of each kidney that are composed of a cortex and medulla
-they release hormones that help us resist stress
96
what is the adrenal cortex composed of
glandular epithelium/tissue
97
what is the adrenal medulla derived from
sympathetic nervous tissue
98
what are the 3 classes of corticosteroids
mineralocorticoids in the zona glomerulosa
glucocorticoids in the zona fasiculata
gonadocorticoids in the zona reticularis
99
what is the major hormone of mineralocorticoids
aldosterone (95% of all)
100
what do mineralocorticoids do?
regulate the electrolyte concentration of extracellular fluids
-most important electrolytes are sodium and potassium
-also helps to regulate water balance (osmotic gradients)
101
actions of mineralocorticoids
stimulates sodium reabsorption in the distal parts of kidney tubules (also from sweat, saliva, and gastric juice
- sodium can make an osmotic gradient which affects movement of water and other ions and effects blood volume and pressureh
102
how do mineralocorticoids affect blood volume and pressure
if sodium moves into the bloodstream, water follows and this adds more blood volume into the blood vessels and results in increased pressure against the vessel walls
103
mineralocorticoid feedback
humoral triggers cause an increase in aldosterone
-high potassium levels in blood
-low sodium levels in blood
-low blood volume
-low blood pressure
104
what is the most important mechanism of aldosterone production
renin-angiotensin mechanism
105
renin-angiotensin mechanism of aldosterone production
-the liver constantly produced a protein called angiotensionogen which is an inactive protein
-under the proper stimulate (low BP, low blood volume), the kidneys start to produce renin and this converts angiotensinogen to an active form called angiotensinogen II
-angiotensin II activates the zona glomerulosa of the adrenal cortex to produce aldosterone and this causes sodium reabsorption
106
plasma concentration mechanism for aldosterone production
when sodium levels in the blood are low and potassium levels are high, aldosterone is produced by zona glomerulosa
107
ACTH mechanism for aldosterone production
stress causes the hypothalamus to produce CRH which causes the anterior pituitary to produce ACTH, which causes the adrenal cortex to become active
-this mechanism only produces a very small amount
108
atrial natriuretic peptide (ANP) mechanism for aldosterone production
stretch on the walls of the heart due to high blood pressure will release ANP and shut off the production of aldosterone
-decreases blood pressure
109
what is the only mechanism of aldosterone production that DECREASES blood pressure?
atrial natriuretic peptide mechanism
110
major hormone of glucocorticoids
cortisol- regulates energy metabolism in response to stress
111
actions of glucocorticoids
maintains blood sugar levels
-cortisol stimulates a process called gluconeogenisis
maintains blood volume
-prevents the uptake of water from the bloodstream by cells
112
what is gluconeogenisis
the production of new sugars from non-carbohydrate substances (like fats or proteins)
113
glucocorticoid feedback
CRH released by hypothalamus which promotes the release of ACTH. this activates the adrenal cortex to produce cortisol
-increased cortisol inhibits CRH release by the hypothalamus
114
what are the effects of stress (increased cortisol levels)
-increase gluconeogenisis
-liberate fatty acids for energy (taken out of storage)
-break down proteins into amino acids
-assist in vasoconstriction
115
what do gonadocorticoids produce
weak androgens (most common is DHEA)
116
what is dehyroepiandrosterone
DHEA is the precursor that gives rise to hormones like testosterone and estrogen
-helps time puberty
117
what does testosterone provide for women
sex drive
-increased libido
118
gonadocorticoids feedback
increased ACTH stimulates the production of the gonadocorticoids
-no shutoff mechanism
119
what are the hormones of the adrenal medulla
epinephrine and norepinephrine
-they combine to create adrenaline (synergists)
120
histological composition of adrenal medulla
chromaffin cells
-modified ganglion sympathetic neurons
-they produce norepinephrine and epinephrine which are released into the bloodstream
121
actions of epinephrine and norepinephrine
promoted by stress and stimulates sympathetic nervous system
-blood sugar rises
-blood vessels constrict
-heart beat increases
-blood pressure rises
-blood is diverted to brain, heart, skeletal muscle, and preganglionic sympathetic nerve endings in adrenal medulla (organs for figth or flight!)
122
pancreas
located in the abdominal cavity behind the stomach and connected to the small intestine
123
exocrine portion of pancreas
secretes substances into a duct that are used for digestion
124
endocrine portion of pancreas
some of the tissue of the pancreas secretes hormones that go directly into the bloodstream
125
histological composition of the exocrine portion of the pancreas
made up of acinar cells
126
histological composition of the endocrine portion of the pancreas
pancreatic islets (islets of langerhans)
-alpha cells produce glucagon
-beta cells produce insulin
127
actions of glucagon
increases blood sugar levels
-functions on the liver to release glucose into the bloodstream
-breaks glycogen down into glucose
-synethesizes glucose from lactid acid and non-carbohydrate molecules
128
feedback of glucagon
low blood glucose and/or high amino acid levels have a humoral effect on the pancreas and causes it to release glucagon
-sympathetic nervous stimulation promotes release and GHIH inhibits release
129
insulin actions
lowers blood sugar levels
-stimulates fat and protein metabolism
-enhances membrane transport of glucose into cells
-inhibits breakdown of glycogen into glucose
-inhibits the conversion of amino acids or fats to glucose (gluconeogenisis)
promotes the oxidization of glucose of ATP production
130
insulin feedback
high blood glucose has a humoral effect on the pancreas and stimulates beta cells to produce insulin
-parasympathetic nervous stimulation causes release
-hormonal influences also stimulate beta cells to produce insulin
131
Gonads
male= testes
female=ovaries
131
testosterone actions
-maturation and maintenance of male reproductive organs
-male secondary sex characteristics (facial hair, deep voice)
-increases sex drive
-sperm production
132
estrogen actions
maturation and maintenance of female reproductive organs
-female secondary sex characteristics (breast development, deposition of adipose tissue)
133
progesterone functions
fucntions with estrogen to promote breast development and cause cyclic changes in uterine lining to regulate the menstrual cycle
134
feedback of sex hormones
regulated by gonadotropins
135
pineal gland
extends from the roof og the 3rd ventricle in the diencephalon
136
histological composition of the pineal gland
made up of cells called pinealcytes
-produce melatonin
137
actions of melatonin
promotes drowsiness
inhibits sexual maturation (helps with timing of puberty)
-pinealocytes are suppressed when sun is up and active when sun is down
138
thymus
gland beneath the sternum in the thoracic cavity
-size diminishes with age (most activity occurs early in life)
139
hormones of the thymus
-thymoproteins
-thymic factor
-thymosins
140
all hormones of the thymus functions...
function in immunity
-influence the development of white blood cells (T lymphocytes) that go out and recognize specific pathogens and attacks them
-stronger immunity when we're young
141
hormone the heart produces
ANP
142
actions of ANP
inhibits aldosterone and changes the composition of urine by acting on the kidneys
143
GI tract hormones
many hormones are produced that regulate digestive system activity
144
hormones produced by the placenta
estrogen, progesterone, and hCG
145
actions of placental hormones
exist only during oregnancy
-links maternal circulation with fetus
-takes over the ovaries and keeps the uterus nutrient rich and vascular
146
hormone produced by the kidneys
erythropoitein
147
erythropoitein functions
stimulates the kidneys ti produce red blood cells
148
hormone produced by the skin
cholecalciferol
149
cholecalciferol actions
activated by the liver and helps absorb calcium in the intestines
-this is the inactive form of vitamin D3
150
hormone produced by adipose tissue
leptin
151
leptin actions
as we store more and more fat in adipose tissue, it produces leptin
-acts on the amygdala to decrease appetite
-increases energy expenditure
152
what embryonic layer do the (steroid hormones) gonads and adrenal cortex come from?
the mesoderm
153
what embryonic germ layer do the amino acid hormone structures come from?
ectoderm and endoderm
154
how does age change the rate of hormone production?
-women stop cycling and go through menopause
-men see a decrease in testosterone levels
155
testes
male gonads that produce gametes (sperm)
156
scrotum
muscular sac outisde the abdominal cavity that testes are stored in
157
epididymis
where immature sperm is stored
158
ductus deferens
pathway that carries sperm into the males body
159
ejaculatory duct
connects vas deferens to the urethra
160
urethra
pathway of sperm and urine out of the body
161
penis
specialized copulatory organ that is outside the body
-allows deposition of gametes into the females body
162
seminal vesicles
secrete alkaline fluid as a defense mechanism
163
prostate gland
produces prostatic secretions
-increases in size with age
164
bulbourethral gland
two of these (aka cowper's glands)
-they secrete mucus and work as a lubricant
-known as pre-ejaculation
165
lobules
divides the testes into compartments
-each has elaborate tubules known as seminiferous tubules
166
seminiferous tubules
highly branched tubules
-the "factory"
-actual site of sperm production
-NOT MATURE SPERM
167
tubulus rectus
each lobule has one of these that merge out to the rete testis, a channel between seminiferous and rete testis
168
rete testis
hub of tubules, central hub of where all tubules connect
169
efferent ductus
"exits from"
immediately leaving tubes from rete testes, carry immature sperm from the rete testes to epididymis
170
epididymis
stores BILLIONS of sperm
171
interstitial cells (of Leydig)
cells located between the seminiferous tubules
-activated by LH to produce testosterone which helps stimulate sperm production
172
explain testicular blood flow
blood is supplied by testicular arteries and is drained by the testicular veins
-blood delivered to testes is COOLER
173
what makes blood delivered to the testes colder?
the pampiniform plexus
174
how is blood cooled by the time it reaches the scrotum?
as the arterial and venous blood pass each other, the heat from the arterial blood gets dissipated into the cooler venous blood and the arterial blood is cooled
175
define the scrotum
a sac-like structure outside of the males body that consists of skin and a superficial fascia
176
muscles of the scrotum
-via dartos and cremaster
involuntary muscles that contract when cold and relax when warm to move the testes closer and farther from the body
-helps maintain optimal temperature
177
what temp is the scrotum kept at?
34 degrees celcius
-3 degrees below body temp
178
3 regions of the penis
1. head (glans) -> covered with prepuse "foreskin"
2. shaft
3. root
179
circumcision
surgical removal of the prepuce (foreskin)
-some cultures remove this for hygiene reasons
180
corpora cavernosa
two large bodies of erectile tissue that keep the urethra open when the penis fills with blood so sperm can pass through
180
erection
change in size and rigidity of the penis
181
corpus spongiosum
single smaller tissue at the bottom of the penis that surrounds the urethra
182
erectile tissue
spongy networks of connective tissue, smooth muscle, and vascular space that fill with blood upon sexual arousal to make the penis larger and firmer
-collapses the veins that drain the penis and traps the blood
183
epididymis
two of these accessory ducts
-billions of immature sperm stored here (come from the seminiferous tubules)
-sperm stays here unless enough sexual arousal occurs
184
ductus (vas) deferens
two of these accessory ducts
-tubes that carry sperm from the epididymis up towards the urinary bladder/torso
185
vasectomy
a surgical procedure where the vas deferens are cut and cauterized so sperm cannot be released
~99.9% effective
186
ejactulatory duct
two of these accessory glands
-each ductus deferens empty into these short ducts
-connects to the urethra
187
urethra
carries reproductive and urinary fluids
-urine is toxic to sperm
-sphincter at the end of bladder shuts off the opening to the bladder during sexual arousal
188
how many days does it take sperm to acquire the ability to swim?
20 days
-they swim using flagella
189
how long can sperm be stored?
7 months
-if not used, they are phagocytized
190
seminal vesicles
two of these accessory glands
-they surround ejaculatory duct on each side
-paired organs that secrete alkaline fluid to neutralize acidic vagina
191
prostate gland
located where the urethra starts
-secretes enzymes and nutrients upon stimulation
-senzymes cause activation of sperm and nutrients feed mitochondria to give them energy to swim
192
bulbourethral glands "cowpers glands"
two of these
-tiny, pea sized glands that secrete mucus into semen
-cleans out residue left behind by urine
-provides lubrication to ease insertion into the females body
193
what is semen
glands collectively secrete this
-bulbourethral glands are activated before the others and release pre-ejaculation
194
erection phase
parasympathetic (POINT)
-involuntary
-visual stimulus for men
195
Ejaculation phase
sympathetic (SHOOT)
-voluntary (must have sex or some sort of friction to cause this to happen)
196
spermatogenesis
the production of spermatids in the seminiferous tubules
-males start to produce sperm at puberty and continue until death
~400 sperm per day (begins ay basal lamina and products are released into lumen)
197
spermiogenesis
the modification of spermatids to become spermatozoa
-differentiation process
198
parts of the spermatozoan
-head
-acrosome
-midpiece
-tail
199
how many days does it take to go from a primary spermatocyte to an immature sperm
64-72 days
200
head of the spermatozoan
genetic component
-where all DNA is
201
acrosome of spermatozoan
the very end of the head
-a vesicle that helps get through the covering of the egg
-has acrosomal enzyme that is used in fertilization
202
midpiece of the spermatozoan
hs lots of mitochondria that get nutrients from the prostate gland to make energy for the flagellum to contract
203
tail of spermatozoan
cytoplasmic extention called the flagellum that makes the sperm swim
204
sustentacular cells
AKA 'sertoli' or 'nurse' cells
-haploid sperm appear foreign to the body so the immune system tries to kill them, these cells protect the sperm
205
actions of sertoli cells
-protect developing spermatocytes from the immune system by creating a blood-testes barrier in the male reproductive tract
-nourish dividing cells by having secretions to help the cells divide
-helps move cells to the lumen so they can be transported to the epididymis
-secretes sustentacular/testicular fluid which functions as a transport medium in the lumen and fills lumen of seminiferous tubules to help get the spermatids to the epididymis
-dispose of eliminated cytoplasm (get rid of defective sperm)
-regulate spermatogenesis
206
role of FSH
-stimulates sertoli cells to release androgen-binding protein (ABP)
-ABP attaches to outside of spermatogonia & causes them to accumulate testosterone
207
role of LH
helps with sperm production
-causes interstitial cells in the seminiferous tubules to secrete testosterone (also very small amount of estrogen)
208
role of testosterone
-stimulates spermatogenisis (through binding of testosterone to ABP)
-inhibits GnRH (as testosterone levels increase, this shuts off GnRH which then inhibits gonadotropin release
-has anabolic effects on accessory reproductive organs (develops and maintains them)
-promotes male secondary sex characteristics (strong bones, increased muscle mass, hair production, oily skin, deep voice)
-boosts BMR (basal metabolic rate)
-influences behavior (increases sex drive and aggression)
209
role of inhibin
produced by sustentacular cells when sperm count is high
-inhibits release of FSH and LH by inhibiting GnRH
-shuts off production of ABP and stops gonadotropin production
210
ovaries
site where gametes are produced
211
oviducts
pathway that carries eggs to the uterus
-site of fertilization (in the ampulla)
212
uterus
thick-walled muscular organ that receives, retains, and nourishes the fertilized ovum
site of implantation and embryonic development/gestation
213
vagina
female organ of copulation
where sperm are deposited
birth canal
passage for menstrual flow
214
external genitalia
also called vulva
includes labias, mons pubis, clitoris, etc
215
mammary glands
produce milk to nourish newborn
modified sweat gland
216
where are the ovaries formed
in the ovarian cortex before birth
217
follicular cells
first layer surrounding the oocyte
218
granulosar cells
each subsequent layer above follicular
219
primordial follicle
in the body when born
oocyte is surrounded by ONE layer of epithelial cells
women born with ALL the primordial follicles they will ever have
SOME start to ripen
220
primary follicles
develops from a primordial follicle
TWO or more layers of cells around the oocyte
has both follicular and granulosar cells!
221
secondary follicle
only one or two primary follicles develop into this each month
-will develop a fluid-filled cavity called an andrum
222
graafian follicle/vesicular
generally, only one secondary follicle continues to mature into this
much larger in size, oocyte is pushed away from center and sits up on a stalk
appears like a blister on the surface of the ovary
ruptures to release oocyte and follicular fluid in a process called ovulation -> fills with blood to become corpus hemorrhagicum
223
corpus luteum
ovarian follicle turns into this
a glandular structure which secretes hormones that get the uterus ready for implantation (specifically progesterone)
if fertilization occurs- this is maintained for a few months and then degenerate
if fertilized does NOT occur- this will degenerate right away
224
corpus albecans
corpus luteum becomes this where or not fertilization occurs
-a scar on the ovary
225
where is the ovulated oocyte released from the ovary into?
the peritoneal cavity
it gets released into the abdomen & ciliated fimbriae help it get to the uterus
226
oocyte path to uterus?
ovary -> oviduct -> infundibulum -> ampulla -> isthmus -> uterus
227
infundibulum
the closest part of oviduct to the uterus
has cilia which are stimulated to pulse and create a contraction to pull the egg into the oviduct (also what prevents sperm from getting in)
228
ectopic pregnanyc
the fertilized egg will implant itself anywhere other than the uterus (typically in the oviduct)
- life-threatening to mom and baby
228
body of uterus
central part
"pear shaped"
where fetus resides
228
fundus
above where the oviducts meet
above the body
228
ampulla
part of the oviduct
normal site of fertilization!
229
cervix
"neck" of the uterus
230
internal os
opening of cervix at the top
cervix & uterus
231
external os
opening of cervix at the bottom
cervix & vagina
232
cervical opening width
normally the width of a human hair
dilates to 10 cm during birth
233
cervical plug
mucus that develops during pregnancy to block foreign things in the vagina from reaching the baby
234
how does the uterus propel sperm toward the egg
it has rhythmic, reverse peristalsis
235
perimetrium
outer layer of the uterine wall
236
myometrium
middle layer of the uterine wall
-muscular layer
-- involuntary smooth muscle
237
endometrium
inner lining of uterine wall
- highly vascularized and glandular portion (has soft mucosal lining)
238
stratum functionalis
innermost layer of the endometrium where implantation occurs
- if fertilization does NOT occur, this is what is built up and sloughed off
239
stratum basalis
portion of the endometrium that is closest to the muscle
causes thickening and vascularization of the stratum functionalis
- hormones cause it to rebuild the stratum functionalis when it is sloughed off
240
vagina
female organ of copulation that is the "receptive organ"
birth canal where baby passes through
passage for menstrual flow
241
why does the vagina have an acidic environment
an immune function
-prevents bacteria and foreign bodies from getting in
242
hymen
thin layer of tissue that covers the opening of the vagina
-most girls born without completely intact
- not a proper way to check for virginity
243
mons pubis
fatty tissue on top of the pubic symphysis
prevents pain during intercourse
has many hair follicles
244
labia majora
outer folds that do have hair follicles associated with it
245
labia minora
inner folds that do not have hair follicles
246
greater vestibular glands
associated with the walls of the vagina and labia minora
- parasympathetic impulses stimulate production of mucus to aid insertion of the penis upton sexual arousal
**female counterpart to male bulbourethral gland**
247
clitoris
a collection of erectile epithelial tissue (cavernous tissue) which fills with blood upon sexual arousal
-MANY nerve endings
248
perineum
the tissue between anus and vulva
often cut or torn during labor
249
episiotomy
surgically cut the perineum before it tears for an easier healing process
250
mammary galnds
both males and females have them but only functional in females due to hormonal regulation
251
lobes
divide the mammary glands
252
lobules
divides the lobes of the mammary glands
253
alveoli
tiny sacs that produce milk
254
lactiferous ducts
milk is carried through here from the lobules to the sinus
255
lactiferous sinus
where milk is stored
beneath the nipple
256
areola
colored area to guide the baby where to suck
257
nipple
where the baby places its mouth to express milk
258
oogenesis
the process of gamete production BEFORE birth
and then stops. will then start up again during puberty and end at menopause
259
how many viable gametes?
only 500 viable gametes of the original 2 million primary oocytes will be ovulated
one per month for around 40 years
260
how many oocytes get fertilized?
average is about 2- ones that actually finish meiosis II
**this is dependent on how many children you have
261
what happens if fertilization DOES occur?
secondary oocyte completes meiosis II
produces one ovum and the second polar body
ovum is haploid and then becomes diploid as soon as the sperm combines with it
total produced= one ovum and three polar bodies
262
what happens if fertilization DOES NOT occur?
the secondary oocyte degenerates and never finishes division (meiosis II)
263
follicular phase
growth of a follicle (primordial follicle -> primary follicle -> secondary follicle -> graafian follicle)
includes everything prior to ovulation
14 days long in regular 28 day cycle
**variability in length of menstrual cycle occurs here**
264
cell vs follicle
secondary follicle contains a primary oocyte at first, which develops into a secondary oocyte (this is what actually gets ovulated)
a graafian follicle always contains a secondary follicle
265
ovulation phase
the ovary wall ruptures and the oocyte and corona go into the peritoneal cavity
only one secondary oocyte is ovulated
266
what increases the chance of twins
genetics- twins skip a generation
age- as you get older, more likely
267
luteal phase
includes everything after ovulation
this phase is ALWAYS 14 days long
the corpus hemorrhagicum forms and reabsorbs
the granulosa and theca cells make corpus luteum and that secretes progesterone and estrogen
either becomes placenta OR corpus albicans (scar)
268
fraternal twins
produced from hyperovulation
genetically different and can be different sexes
269
hyperovulation
where you ovulate more than one oocyte and each of them is fertilized by its own sperm
270
identical twins
one oocyte is fertilized by one sperm but when it divides, it separates and produces two independent zygotes
genetically identicall and cannot be different sexes
271
hormonal regulation of female prior to puberty
the ovaries produce SOME estrogen (which inhibits GnRH and prevents the production of FSH and LH)
272
hormonal regulation of female during puberty
the hypothalamus becomes less sensitive, there is not enough estrogen to stop GnRH so FSH and LH start to be rhythmically produced
this causes menarchy
273
why is there no regularity for your first few menstrual cycles
hormones are unsteady
can take 3 years to steady out (some women never do)
274
role of FSH in female
stimulates follicle cells
causes growth and maturation of follicle
-stimulates primordial follicle to ripen
275
role of LH early in the cycle
LH causes thecal cells of the secondary follicle to produce androgens
- androgens are converted to estrogen by gransulosa cells (they release the estrogen and it circulates in the body)
276
role of estrogen
the initial rise in estrogen level inhibits the release of FSH and LH (it is still stored in the anterior pituitary, just not released)
-LH stimulates the continuation of follicle development (estrogen production increases)
-the increase in estrogen levels causes a flood of LH (what was previously stored)
277
non-cyclic (not related to development of the follicle) role of estrogen
-anabolic effects (maturation of female sex organs and reproductive tract)
-supports short term growth spurt of girls at puberty (occurs before male)
-promotes female secondary sex characteristics (smooth skin, less oil, increase in fat composition around hips and breasts)
278
role of LH during cycle
the surge in LH stimulates the completion of meiosis I by the dominant primary follicle
-one of these will go through ovulation which inhibits estrogen production (surge of LH stops)
-transforms the ruptured follicle into the corpus hemorrhagicum and then corpus luteum
- then progesterone and estrogen are produced from the corpus luteum
279
role of progesterone in female
inhibits FSH and LH production
280
role of inhibin in female
inhibits FSH and LH production
-stops things in the ovary
-suppresses FSH and LH when pregnant so we don't develop any more follicles
281
uterine cycle
the menstrual cycle (changes in the endometrium)
-highly coordinated with ovarian cycle
282
menstrual phase of uterine cycle
begins with menses (blood)
- ovarian hormones are at their lowest level- lack of hormone causes the functional endometrium to be sloughed off
-menstruation occurs (bleeding)
-lasts 3-5 days
-experience increase in receptors for progesterone increase
-occurs at same time as ovarian follicular phase
283
proliferative phase of uterine cycle
-FSH and LH levels increase which causes estrogen levels to increase and the endometrium rebuilds itself
-progesterone receptors develop in the endometrial cells
284
secretory phase of uterine cycle
-progesterone receptors increase and the progesterone causes the endometrium to prepare for implantation and form the cervical plug
-decreasing progesterone and LH levels initiate breakdown of the endometrium and the cycle starts all over again
285
why does the endometrium shed
it is sloughed off to rebuild and constantly create a healthy lining for possible implantation
286
explain the female sexual response
mostly psychological arousal
- blood engorges in the clitoris upon parasympathetic nervous activity
-the vestibular gland is stimulated by friction to produce mucus and aid in insertion
-orgasm does not always happen and no refractory people
-climax does not have to occur for the female to be impregnated
287
human sexual development
the gender is determined by male -> X or Y sperm
-embryo is sexually indifferent until 2 months post-conception
-development of gonads begin 5-6 weeks post conception but do not differentiate until 2 months
288
sexual differentiation
gonadal ridges begin to form 5 weeks post conception
mullerian and wolffian ducts develop
primordial germ cells are depostited
genital tubercle develops and contains the urethral groove, urethral fold, and labioscrotal swellings
289
mullerian ducts
female
290
wolffian ducts
male
-men are dogs and wolfs are close to dogs
291
urethral groove is
the external opening of the urogenital sinus that forms the urethral oepnings
292
urethral folds are
on the sides of the grooves
293
labioscrotal swellings are
on the sides of the folds
will develop into either a labia or scrotum
294
steps of male sexual differentiation (all directed by SRY gene)
1. seminiferous tubules form in gonadal ridges and link with wollfian ducts
2. the developing testes secrete anti-mullerian hormone (AMH) which causes the mullerian duct to degenerate
3. genital tubercle enlarges to form the penis
4. labioscrotal folds fuse to form the scrotum
5. urethral folds fuse to form the urethra
6. testosterone production guides secondary sexual developlemt (continues development of sex organs)
7. testes descend into scrotum approximately 2 months before birth
295
female sexual differentiation
1. gonadal ridges form the ovaries
2. follicles form in the cortex of ovaries (they start to deposit and get surrounded by germinal cells
3. mullerian ducts differentiate and nothing stops their generation while wollfian ducts degenerate because there is nothing promoting their generation
4. genital tubercle gives rise to the clitoris
5. urethral groove becomes vestibule
6. urethral fold stays unfused and becomes the labia minora
7. labioscrotal folds stay unfused and become the labia majora
8. ovaries descend, but only to the pelvic brim (stay inside the body)
296
what is the female counterpart to the penis
the clitoris
297
what does the urethral groove give rise to in women
the vestibule
298
what does the urethral fold turn into in female
the labia minora
299
what does the labioscrotal fold turn into in female
the labia majora
300
process of fertilization
sperm fuses with a secondary oocyte and finishes meiosis II to form a zygote
-sperm is viable for 72 hours
-oocyte is viable for 24 hours
(4 day window to get pregnant)
301
4 barriers to prevent fertilization
1. loss of sperm from the vagina
- men release millions of sperm, not all of them stay
2. vaginas acidic environemnt
3. consistency of cervical mucus
- contractions during ovulation work against sperm
4. phagocytic cells in the uterus
- sperm try to fertilize ANY cell, they can choose the wrong one
302
capacitation
sperm are incapable of fertilization immediately after ejaculation so they go through this process for 6-8 hours
- the membrane gets thinned out by the swimming action of sperm and this allows acrosomal enzymes to be released
-change in tail activity
303
acrosomal reaction
the sperm will bind with the zona pellucida and the acrosomal enzymes are released to digest the zona pellucida
-hundreds of sperm do this but only one will end up penetrating the oocyte
304
fast block to polyspermy
membrane dpolarization
the union of sperm to the oocyte causes sodium channels to open
- the membrane depolarizes and nothing gets in
305
slow block to polyspermy
cortical reaction
-once sperm penetrates the oocyte, the endoplasmic reticulum releases calcium and water comes in, pushing the sperm away
-this causes the membrane to spill enzymes and kill receptors
306
what happens if two sperm penetrate one egg
miscarriage
307
process of implantation
occurs 6-7 days after ovulation
the egg embeds itself into the stratum functionalis
human chorionic gonadotropin (hCG) secreted by the zygote, maintains the corpus luteum
- this causes progesterone production and maintains the lining -> eventually the placenta takes over
308
chroion
external embryonic membrane
chorionic villi are the baby's capillary beds
309
amnion
deep embryonic membrane
contains amniotic fluid which provides cushion, float, and protects the baby
-it breaks after thinning and this is your water breaking
BIOL 2230
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