Section 6 pituitary Anatomy Flashcards
No projections of neurons into this lobe:
anterior
What triggers the neuron synthesizing topic hormones?
Activity of hypothalamus, floods endocrine cells in anterior pituitary gland
True or False? Many neurons are needed in the hypothalamus to release hormones.
F. only a few
slice infindibulum:
cut off communication of both the portal system and the neural lobe, neurons may regenerate, project down, and regain some function, no blood supply will come back to anterior pituitary gland.
Controls of hypothalamic centers:
heat, energy, hunger, satiety, body mass, BP, HR, sweat, blood volume, intake-thirst, output-urine volume, metabolic rate, stress, growth, reproduction, lactation
True or False? Pain can act on the neurons that control the pituitary gland, i.e. hear baby cry and start lactating
T. let down reflex
Pro-opiomelanocortins (POMC):
ACTH, ADH (adrenal control)
Two subunit glycoprotieins:
TSH, LH, FSH, alpha unit is the same to all these
3 classes of hormones released from anterior pituitary gland:
glycoprotieins, pro-opiomelanocortins, large single chain proteins
Large single chain proteins:
GH, prolactin
Are PMC’s small or large?
small
ACTH is released by this cell:
corticotroph
What does the hypothalamus release to activate or inhibit the corticotroph cell?
corticotropin-Release Hormone (CRH)
how does the CRH get from the hypothalamus to the corticotrophs?
potral circulatory
ACTH affects what target?
adrenal cortex (growth and function of gland)
Inhibiting hormones of ACTH, PIMC, MSH, B-lipotropin, gammea-lippotropin, B-endorphin, N-terminal peptide:
none
Major cleavage products of POMC:
ACTH, different versions of MSHs, endorphins, and others.
Corticotroph tumor or tumor secreting lots of ATCH:
processed via POMC (pro hormone), over-secreting ACTH, MSH, and other fragments, pigmentation coloration change
High secretion of ACTH:
darker pigmentation on inside of lips, tongue, and mucosa of mouth
alpha units are all the same for:
Two subunit glycoproteins (LH, FSH, TSH)
Cell type for LH:
gonadotroph (10-15% of cells)
TSH is aka:
Thyrotropin
Release hormone for TSH:
TRH (3 amm)
Inhibiting hormone of TSH:
Somatostatin
Somatostatin (ss) is always:
inhibitory factor/ hormone
Release hormone of LH and FSH:
GnRH
Target of LH:
Testis (testosterone), ovary (Estrogen/Progesterone synthesis, Follicular ovulation)
Only2 hormones synthesized by the same cell type:
LH and FSH
Cell type of FSH:
gonadotroph
Target of FSH:
sperm maturation, follicular growith
Cell type of GH:
Somatotroph (40-55%), Preg: decrease size and number
Functions of GH:
Full body metabolism and growth
Release hormone f GH:
GHRH
Inhibiting hormone of GH:
SS (aka GHIH)
Target of GH:
Liver and other tissues, growth, development, metabolic
Dopamine tonically inhibits mammotroph from releasing:
prolactin
Cell type of prolactin:
Mammotroph (10-25%)(lactotroph) Preg: increase size and number
Release hormone of prolactin:
Prolactin-releasign factors (?) TRH
Inhibiting hormone of Prolactin:
Prolactin-inhibitiing factors (?) (GAP*) Dopamine SS
Target of Prolactin:
Breast, lactation, growth, milk, suppresed menstrual functions
slic infidibulum, how are hormone levels affected:
Prolactin increases because there is no inhibition via portal system (connection wiped out) but TSH, ACTH, GH, FSH, LH are inhibited. constant inhibitory affect by the hypothalamus on prolactin secretion
pituitary gland controlled by:
hypothalamus and higher brain centers
endocrine part of adrenal gland:
cortex
secrete epinephrine and norepinephrine (glucose homeostasis), extension of sympathetic nervous system:
adrenal medulla
Counter regulatory to insulin:
glucagon
What controls the placenta?
none, autonomous, proesterone, estrogen, sometotropins, etc.
Major feedback mechanism in biology:
negative feedback
Location of pituitary gland:
base of skull, out pouching of brain
What lobe is the posterior pituitary gland?
neural lobe, neurohypophysis
True or False? There are synapse-synapse connections between the neural lobe and the hypothalamus
no synaptic connection, synapses neuron to capillary bed
To where does the structure of the pituitary gland project?
sphenoid process
What type of tissue is the anterior pituitary gland made of?
endocrine tissue
Where are the cell bodies located for the pituitary gland?
hypothalamic nuclei
True or False? Neurons release ADH (vasopressin) and oxytocin
T
What makes up the posterior pituitary gland?
Projections from the hypothalamus
True or False? Both the anterior and posterior pituitary gland are controlled by the hypothalamus.
T
Neurons of the pituitary gland synapes here:
capillary bed
Where are the hormones synthesized in the cell?
cell body
Communication in pituitary gland:
is a hormones released from synapse into circulation
Hormone involved in stress
ACTH
How are endocrine cells controlled?
hypothalamus
adenohypophesis communication:
portal capillary circulation a, capacity, vein, cap, vein
Function of portal capillary system:
Transmit signals from hypothalamus to the anterior pituitary gland (adenohypophyis)
Does the posterior or anterior pituitary gland require a factor?
anterior
Benefit of portal system (?)
Direct connection of a small pool of neurons
Urinating too much can be a sign of:
damage to infindibulum
Brain regions that provide input to the hypothalamus:
Reticular activating substance (sleep wake), Thalamus (pain), Neocortex to Limbic System (Emotion, fright, rage, smell), visual system, auditory system
What systems are controlled by the hypothalamus?
visceral systems
What controls the hypothalamus?
higher centers
Which hormone is derived from a precursor protein/
ACTH
Which are the 2 subunit hormones?
LH, FSH, TSH (affect both men and women, way to remember)
What % of cells in the anterior pituitary gland are corticotrophins?
15-20%
How many amino acids is ACTH made of?
39
What is the main POMC?
ACTH
From where are inhibiting and activating hormones released
neurons
What cell type releases MSH?
corticotrophs
Clinical indication that the ACTH system is out of whack>
change in intraoral pigment coloration
Percentage of cells that are Thyrotrophs:
(3-5%)
Is GH more involved in growth or whole body metabolism?
whole body metabolism
How many amino acids is somatostatin composed of?
14
What percentage of tissues is the mammotroph (lactotroph) made of?
10-25%
Major controller of prolactin:
contant inhibition via dopamine
How many amino acids is GH made of?
191
How many amino acids is prolactin made of?
199
True or False? prolactin is involved in milk ejection.
F. oxytocin is
Another function of prolactin:
suppress the menstrual cycle, longer you breast feed the longer it will be before your next cycle
For all except prolactin, if you cut the infundibulum stalk:
All the levels of the other hormones will decrease
Constantly inhibit the production of prolactin:
dopaminergic neurons, gets rid of the dopamine influence
Levels of this hormone are low during the day and rise 1-2 hours after you fall asleep:
GH, go to sleep and you will grow (mom says :-))
True or False? The growth spike from GH diminishes with age.
T
What will inhibit GH?
High carbohydrates, cortisol, ss
Will wil upregulate GH production?
Arginine
Pituitary stalk is aka:
Median eminence
Functions of cell bodies of posterior pituitary gland
make, produce and process hormones
True or False? Posterior pituitary gland hormones are large hormones.
F. 9 amino acids, nonapeptides
Half life of short peptides:
minutes to hours
Steroids require this for transport in system:
carrier protein
What is Arginine vasopressin?
ADH
In which nuclei are oxytocin and ADH made?
supraoptic nuclei and paraventricular nuclei (SON and PVN)
Classic response to oxytocin
effects on both breast tissue and uterus, cause contractile activity in muscle cells or myoepithelial cells that surround duct and breast tissues. Squeeze blind sacs filled with milk and allow milk ejection
What cells make milk?
Acing cells in ductal tissues
Myometrium is what?
smooth muscle cells of the uterus
Delivery (of baby):
partruition
True or False? Oxytocin is the trigger for birth.
F. Oxytocin can be used (patosin) pharmacologically to induce labor, but not the physiological trigger for labor
True or False? All biologically systems have a feedback system to maintain homeostasis.
T
The uterus is line with what type of fibers?
C fibers (pain receptors)
Stimulate cervix and stretch receptors and this will happen:
stimulate activation of pathways that lead to oxytocin release
How does oxytocin travel to the uterus?
Systemic circulation
Pushing the baby out will:
lead to more dilation, this is a positive feedback mechanism
What leads to the release of stretch receptor activation?
birth of baby
Myometrium contributes to this, in addition to pushing baby out:
delivery of the placenta
Muscle squeezing:
cuts off blood supply to the baby, ascetic, squeezing due to oxytocin leads to vasoconstriction so that mom doesn’t bleed to death
What type of feedback system is related to breast feeding?
positive
What can happen in conjunction with breast feeding?
contractions, helps to bring the uterus back to prepregnacy size, let down reflex
Sex hormone:
oxytocin, receptors all throughout brain, involved in stress, empathy, social body, increased during sexual activity, increased bonding
Polymorphisms in oxytocin receptors:
behave differently, different levels of stress and different empathy
Strong stimuli from ADH:
cardiovascular effects
Controls of ADH release:
Osmoreceptors, volume/ pressure receptors
Vasopressor action:
increase blood pressure
2 systems that are activated to regulate ADH:
cardiovascular system and CNS
ADH effect these 2 systems:
kidney and cardiovascular system, pee less or drink more
Location of plasma receptors:
AV3V
Direct stimulation of supraoptic nuclei and paraventricular nuclei:
AV3V
2 things AV3V activates:
thirst and supraoptic nuclei and paraventricular nuclei, to add water to body
True or False? The thirst mechanisms has an immediate response.
F. delayed
How dehydrated are you by the time you sense thirst?
0.5 to 1L
Where is low pasta volume sensed?
changes in blood volume and plasma volume heart, aortic and carotid baroreceptors, stretch receptors (C fibers and other A type fibers)
When blood pressure is high how is the CNS affected?
shut down
True or False? When blood volume decreases more neural input is sent to the CNS to increase blood volumes.
F. less neural input
True or False? Decreases capillary hydrostatic pressure will lead to the recruitment of extracellular fluid.
F.
