Lecture 20 Flashcards
Critical regulatory center of the nervous system is the _______ and is the major _______ between the nervous system and the endocrine system
Synthesizes a variety of different “R” (Releasing) and Inhibiting hormones:
TRH, GnRH, GHRH, CRH, and also ADH, Oxytocin, Prolactin inhibiting hormone (dopamine), Growth hormone inhibitory hormone (somatostatin)
hypothalamus
link
Pituitary gland secretes a number of different hormones
Together, the Hypothalamus and the Pituitary gland regulate __________
growth, development, metabolism, and homeostasis
Hypothalamus controls the secretion of the _______ pituitary
Does this by secretion of hormones called ______ and _______ hormones
These hormones are transported to the anterior pituitary through minute blood vessels called _______
anterior
hypothalamic releasing
hypothalamic inhibitory
hypothalamic-hypophysial portal vessels
Hypothalamic hormones reach the anterior pituitary gland through the ________ system
Transports blood from a ______ capillary network to capillaries into a _____ capillary network (in the anterior pituitary) without passing through the _____
Hormones will then pass into the anterior ________and out into the general circulation to travel to target tissues
hypophyseal portal
primary
second
heart
hypophyseal veins
____________ (branches of internal carotid arteries) bring blood to the hypothalamus.
At the _________ these arteries divide into a ___________ of the hypophyseal portal system
This plexus drains blood into the ________ which pass down the infundibulum
Within the pituitary the portal veins divide into a _________ of the hypophyseal portal system
Superior hypophyseal arteries
infundibulum
primary capillary plexus
hypophyseal portal veins
secondary plexus
Pea-shaped structure about ½ inch in diameter
Pituitary Gland
pituitary gland lies within the ________ of the ________ of the ______ bone
Attached to the hypothalamus by a stalk called the ________
Anterior/posterior two different cell types
hypophyseal fossa
sella turcica
sphenoid
infundibulum
2 structurally and functionally different areas of the pituitary or hypophysis
Anterior Pituitary (adenohypophysis)
Posterior Pituitary (neurohypophysis)
Anterior Pituitary (adenohypophysis) accounts for ____% of the total weight
contains _____ different types of hormone-secreting cells
75%
5
Posterior Pituitary (neurohypophysis) contains ____ and ________ of more than 10,000 different neurons
cell bodies of these neurons are located in the _______ and _______ of the hypothalamus
secretes ____ major hormones of the endocrine system
axons
axon terminals
supraoptic
paraventricular nuclei
two
Regulates a wide range of physiologic functions from growth to reproduction
anterior pituitary
40% of cell mass is __________
secrete ______________
hGH stimulates a variety of tissues to secrete ___________, which stimulate body growth and regulates metabolism
Somatotrophs
human growth hormone (hGH or somatotropin)
insulin-like growth factors (IGFs)
secrete thyroid-stimulating hormone (TSH or thyrotropin)
stimulates secretion of thyroid gland
Thyrotrophs
secrete both follicle-stimulating hormone (FSH) and luteinizing hormone (LH)
- both FSH and LH control growth of the ovaries and testes, as well as their hormonal and reproductive activities
Gonadotrophs
secrete prolactin (PL) which stimulates milk production in mammary glands
Lactotrophs
20% of cell mass is ___________
Corticotrophs
Corticotrophs secrete _________ and _________
adrenocorticotropic hormone (ACTH) or corticotropin
melanocyte-stimulating hormone (MSH)
ACTH stimulates the _______ to secrete _______
adrenal cortex
glucocorticoids
MSH stimulates _______, increasing ________
melanocytes
skin pigmentation
human growth hormone is a single chain of ____ amino acids
- Stimulates body growth
- Both cell size and number of cells
- Stimulates secretion of ____________
- Proteins produced primarily in the _____
- Require growth hormone to carry out function of increasing bone growth
191
Insulin-like growth factor -1
liver
Human growth hormone
- Inhibits ______ action on carbohydrate and lipid metabolism
- Promotes _______ synthesis
- Facilitates AA transport across the cell and increases RNA translation
- Limits breakdown of _____
- Stimulates _____, mobilization and utilization of fatty acids as energy
insulin
protein
proteins
lipolysis
human growth hormone
- Conservation of glucose
- _____ glucose uptake skeletal muscle and fat
- _______ glucose production in liver
- ______ insulin secretion by the pancreas
- “_______”: looks like Type II diabetes when GH is in excess. (unknown cause- likely GH’s associated increase in fatty acids)
- GH in absence of carbohydrates or insulin? _______
Decreases
Increases
Increases
diabetogenic
No growth
human growth hormone
- Integral in cartilage formation and bone growth
- Deposition of new cartilage _______ (which converts to bone in growing individuals)
- Promotes ______ activity manufacturing the boney matrix
epiphyseal region
osteoblast (build bone)
stimulate or inhibit GRWOTH HORMONE
- low blood sugar hypoglycemia will _____
stimulate GH
Hypothalamic Stimulation of the Posterior Pituitary
Secretion from the posterior pituitary is controlled by nerve signals that originate in the hypothalamus and terminate in the posterior pituitary
Hormones are secreted by specialized cells called _________ located in the hypothalamus
Hypothalamus produces ____ and _____, packaged into secretory vesicles that are transported via carrier proteins called ______ down to the nerve endings in the posterior pituitary. This process takes several days.
magnocellular neurons
ADH
oxytocin
neurophysins
in the posterior pituitary the hormones are stored until nerve impulses trigger ______ and release of the hormones
hormones enter the posterior pituitary circulation until they reach the general circulation where they travel to their target tissues
exoctyosis
Structure of Posterior Pituitary:
Consists of axon terminals of________ cells which form the ____________ tract.
Blood is supplied to the posterior pituitary by the _______ (branches of internal carotid arteries), which drain into the capillary network of the _______ where OT and ADH are secreted
From this plexus hormones pass into the ________ and into the general circulation where they travel to their target tissues.
hypothalamic neurosecretory
hypothalamohypophyseal
inferior hypophyseal arteries
infundibular process
posterior hypophyseal veins
peptide containing 9 AA synthesized primarily by the ___________
stimulates contraction of smooth muscle of the uterus during childbirth
stimulates contraction of myoepithelial cells in mammary glands for milk ejection (let down).
what hormone is this?
paraventricular nucleus
oxytocin
peptide containing 9 AA synthesized primarily by the ____________
decreases urine volume and sweat gland activity, thus conserving body water
raises BP by constricting arterioles (vasopressin)
supraoptic nucleus
Antidiuretic hormone
(ADH; vasopressin)
Regulation of ADH Production
__________ within hypothalamus
Sensitive to osmotic pressure of serum
_______ in size as osmolarity increases
In the kidney, water will move toward the region of higher solute concentration, i.e. from the ______ solution to the ______ solution, eventually producing an isotonic solution
Movement of water through the membrane requires ________ (in the kidney- collecting tubules)
______ acts on the cell to increase availability of these proteins
Osmoreceptors
Shrink
hypotonic
hypertonic
aquaporins
ADH
Low Blood Volume and ADH Secretion
Trigger: ____________
Sensed by decrease in _________________
In turn sends signals to brain to release ____
Intravascular volume depletion 20%
atrial stretch receptors, carotid, aortic baroreceptors
ADH
The Hypothalamus’ other functions include the ______ System
Limbic
Hypothalamus represents less than____% of the brain mass, but controls most of the _____ system
Also: senses blood levels of various hormones, aids in arterial pressure control and heart rate, stimulates hunger, thirst and the GI tract, initiates satiety after eating, controls bladder contraction and urine production, pupillary dilation, and regulates body temperature. It regulates uterine contractions and stimulates milk secretion in the breasts.
Behaviorally, the hypothalamus stimulates the general activity level, and if overstimulated can lead to __________.
1%
limbic
rage and fighting
Frequently the behavioral aspects are linked to physiologic effects due to this hypothalamic overlap
Satiety is diminished drive to eat, and a sense of tranquility after eating
____ and the reaction to __________ are elicited in the hypothalamus
______ is primarily a hypothalamic-mediated response
Fear
punishment
Sexual drive
These areas of the limbic system provoke _______, as well as causing the sensation of needing to escape.
These centers are in the _________
less potent areas are in the ______________.
fear and shame
mesencephalon
periventricular hypothalamus
thalamus
amygdala and hippocampus
limbic system is our _____ and _____ center
reward and punishment
punishment stimulation and fear can overcome the ________ centers completely, with the result that punishment and fear (anxiety?) can take precedence in the mind over pleasure and reward.
reward and pleasure
Reward: Located primarily in the _____ and the _______, these areas were found by electrically stimulating areas of the brain in primates.
Primates deprived of food will press a lever delivering stimulation to reward centers in the brain rather than receive food.
Less potent reward centers exist in the _________________
Stronger stimuli to the same areas of the brain that are reward centers (lateral hypothalamus) can cause______ (we don’t know why).
forebrain
lateral hypothalamus
septum, amygdala, thalamus, and basal ganglia
rage
Rage comes from the _________. Despite association with reward area of _____________, rage primarily involves the __________ centers
limbic system
lateral hypothalamus
punishment
Held in check by inhibitory signals from the ________, the hippocampus, and the anterior limbic cortex.
Consistent lower-level overstimulus of the reward centers of the brain result in ______________.
ventromedial hypothalamus
placidity and tameness
The hypothalamic pituitary axis is composed of the ______________________
hypothalamus, infundibular stalk, posterior and anterior pituitary
Arginine vasopressin (ADH) and oxytocin are synthesized in the ______________ whose axons terminate in the __________
hypothalamic neurons
posterior pituitary
Hypothalamic growth hormone releasing hormone increases growth hormone secretion from ____________, which in turn stimulate the release of insulin like growth factor 1 from liver
Aging, deep sleep, stress, exercise and hypoglycemia are a few examples known to regulate GH secretion
GH assists in multiple physiologic processes within the body
somatotrophs
