Lecture 20 Flashcards by Sydney Perry

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

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Pituitary gland secretes a number of different hormones

Together, the Hypothalamus and the Pituitary gland regulate __________

growth, development, metabolism, and homeostasis

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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 _______

hypothalamic releasing
hypothalamic inhibitory

hypothalamic-hypophysial portal vessels

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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

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____________ (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

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Pea-shaped structure about ½ inch in diameter

Pituitary Gland

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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

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2 structurally and functionally different areas of the pituitary or hypophysis

Anterior Pituitary (adenohypophysis)
Posterior Pituitary (neurohypophysis)

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Anterior Pituitary (adenohypophysis) accounts for ____% of the total weight

contains _____ different types of hormone-secreting cells

75%

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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

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Regulates a wide range of physiologic functions from growth to reproduction

anterior pituitary

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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)

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secrete thyroid-stimulating hormone (TSH or thyrotropin)
stimulates secretion of thyroid gland

Thyrotrophs

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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

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secrete prolactin (PL) which stimulates milk production in mammary glands

Lactotrophs

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20% of cell mass is ___________

Corticotrophs

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Corticotrophs secrete _________ and _________

adrenocorticotropic hormone (ACTH) or corticotropin
melanocyte-stimulating hormone (MSH)

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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