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Physiology-Glands and Hormones
Exam 2
48
Physiology
Undergraduate 3
10/28/2013

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Term
autocrine secretion
Definition
secretion that affects the cell that is secreting it
cell has a receptor
Term
paracrine secretion
Definition
secretion that affects neighboring cells
has a local effect/local control
regulation of circulation
Term
endocrine secretion
Definition
non-direct secretion
has a global impact
is released into the blood stream and acts on distant targets
Term
exocrine secretion
Definition
released into a gland/surface of body
ex: gut, sweat glands
pheremones are used for communication between animals
Term
endocrine glands
Definition
release endocrine secretions inside body
produces hormones and ensures a ready supply/stockpile
secretes hormones: to maintain homeostasis and a timely/logical response to stimulus
Term
hormone sequence of events
Definition
1. Made by tissues and synthesized by specific tissues of glands
2. secreted into blood stream
3. changes activities of target organ/has an impact
Term
3 ways testosterone levels can be affected in a cock (rooster)
Definition
1. removal of tissue (testes) causes lack of hormone (testosterone) and changes physiology/behavior
2. replacement of tissue (testes) reverses symptoms
3. injection of hormone (testosterone) alleviates symptoms
Term
feedback loop
Definition
maintains a set point (homeostasis)
set point can change, depending on system
short set point: low variability
long set point: potential high variability
Term
Central Endocrine Glands (and 3 examples)
Definition
**GLANDS IN BRAIN**

pituitary
hypothalamus
pineal
Term
Peripheral Endocrine Glands (and 6 examples)
Definition
**GLANDS IN BODY**
thyroid
adrenal
parathyroids
thymus
pancreas
gonads
Term
thyroid glands
Definition
endocrine gland found in the neck, has two cell types

follicular: produces thyroid hormone (increases growth rate, metabolic rate)
parafollicular: produces calcitonin (decreases blood calcium)
Term
thyroid disorders
Definition
hyperthyroidism
hypothyroidism
goiters
Term
hypothyroidism
Definition
not enough hormone
symptoms of low/weak metabolism
Term
hyperthyroidism
Definition
too much hormone
Graves disease: overactivity of thyroid, causes goiters and bulging of eyes
Term
Goiters
Definition
enlarged thyroid
caused by hypothyroidism: when thyroid isn't producing enough thyroid hormone, body increases the size of the gland in an effort to increase hormone production
found in locations where there is an iodine deficiency in the diet: thyroid hormone requires iodine; without iodine to taper off production, body will continue to crease thyroid tissue
Term
thyroid hormone
Definition
regulates rate of metabolism
heat production, stimulates reaction in which glycogen is broken down, increases numbers of target cell receptors for epinephrine and norepinephrine, increases rate of heart contractions
Term
parathyroids
Definition
produces parathormone
decreases blood phosphate levels
increases blood calcium levels

parapthyroid disorder: hyperparathyroidism causes "moans, groans, stones, bones, psych overtones"
Term
4 structural classes of hormones
Definition
amines
eicosenoids
steroids
peptides and proteins
Term
amines
Definition
hormones from amino acids
includes epinephrine/norepinephrine, thyroid hormone
Term
eicosenoids
Definition
family of lipids
hormones that are arachadonic acid derivatives (arachadonic acid is a polyunsaturated fatty acid)
includes thromboxane: aids in clot formation
Term
steroids
Definition
hormones that are synthesized from cholesterol
includes estrogen and testosterone
Term
peptides and proteins
Definition
most common hormones in body
Term
lipid solubility
Definition
affects whether hormone can travel in/out of a cell

thyroid hormone
estrogen and testosterone
(all other hormones are lipid insoluble)
Term
lipid soluble hormones
Definition
thyroid hormone, estrogen and testosterone

most pathways involve traveling through membrane
hormones are carried through bloodstream on carrier proteins
hormone can bind to nuclear receptors or cytoplasmic receptors
goal of lipid soluble hormones binding is go change DNA expression and have long-lasting effects
when bound to carrier proteins, rarely hormones may act like lipid insoluble
Term
lipid insoluble hormones
Definition
1. reception at a membrane bound receptor
2. transduction: binding changes/causes activation **amplification
3: activation of effector protein **amplificaiton
Term
3 major classes of intracellular messenger cascade
Definition
1. cyclic nucleotide monophosphates (cAMP and cGMP)
2. inositol phospholipids (IP3 and DAG)
3. Calcium
Term
Cyclic nucleotide signaling systems
process of events
Definition
1. hormone binds to G-protein coupled receptor (stimulating signal) **amplification
2. G-protein activates and increases activity of Adenylate Cyclase
3. Adenylate Cyclase increases amount of cAMP production (PDE enzyme degrages cAMP) **amplification
4. cAMP increases amount of activated protein kinase A through direct binding
5. PKA phosphorylates effector proteins **amplification

-increased amounts of calcium affects pathways: decreases effectiveness of adenylate cyclase, causes PDE enzyme to become more effective; has opposite effect on cGMP
Term
Inositol phospholipid signaling system (IP3 pathway)
process of events
Definition
1. hormone binds and activates G-protein coupled receptor
2. G-protein activates PLC
3. PLC hydrolizes PIP2 into two major second messengers
-DAG (stays in membrane
4a. activates PKC
5a. PKC phosphorylates effector proteins, which creates cellular responses
-IP3 (stays in cytoplasm)
4b. IP3 releases calcium from endoplasmic reticulum
5b. IP4 brings in calcium
6b. Calcium activates Ca++/CaM kinase
7b. Ca++/CaM kinase phosphorylates effector proteins which creates a cellular response
Term
Ca++ signaling systems
Definition
can readily change (increase/decrease) intracellular calcium concentration
receptor activation (voltage-gated calcium channels, 2nd messenger systems with PKA opening calcium channels)

ways to decrease calcium: pump into endoplasmic reticulum, pump it out across cell membrane against concentration gradient
Term
membrane-associated signaling systems
Definition
membrane-bound receptor is an enzyme
activated enzyme produces cellular response
specifically constrained to cytosol by membrane

is simpler, faster, less amplification, and more Ca++ sensitive than other systems
Term
divergent pathway
Definition
one hormone turns on 2 receptors and pathways

epinephrine turns on Alpha (secretion of fluid via Ca++) and Beta (causes amylase release via cAMP) pathways, which separately affect mammalian salivary gland
Term
convergent pathway
Definition
one hormone turns on 2 pathways but converge at the end

epinephrine turns on Alpha (secretion of Ca++) and Beta (secretion of amylase) pathways, both of which produce phosphorylase kinase which causes glycogenesis
Term
hormonal integration (relationships between hormones)
Definition
hormones ignore each other
synergism: A=effect, A+B=stronger effect than A alone
permissiveness: A=no effect, B=no effect, A+B=effect
antagonism: A and B have opposite effect

hormones can be excitatory or inhibitory
Term
neuroendocrine systems
Definition
neurosecretory cells release neurohormones into blood stream

primary control centers: hypothalamus, anterior pituitary, posterior pituitary
Term
hypothalamus
Definition
receives information from CNS, releases/inhibits CRH to anterior pituitary
Term
Anterior pituitary
Definition
produces hormones that controls other glands/endocrine tissue (tropic)
puts hormones into circulation
some act directly on somatic tissue

specific hormones (ACTH, TSH) stimulate adrenal cortex to release cortisol
Term
Posterior pituitary
Definition
stores and releases hypothalamic hormones

specific hormones (ADH and oxytocin): ADH causes increase in water absorption in kidney, oxytocin causes mammary glands to eject milk and uterus to contract
Term
Molting/ecdysis
Definition
PTTH: neurohormone, produced in brain, tropic hormone that stimulates ecdysone production by prothoracic gland
Ecdysone: produced by prothoracic gland, stimulates apolysis (detachment of old cuticle and skeleton)
Bursicon: neural hormone, promotes cuticle development and hardening
Eclosion hormone: neurohormone, produces shedding of skin
Term
neurohormone
Definition
hormone that comes from brain/spinal cord
Term
hemimetabolus
Definition
organism has similar body structures over course of life (humans)
Term
homocletabolus
Definition
organism's body structures transform over life (insect)

Larva->Pupa->Adult
Term
juvenile hormone
Definition
neurohormone,
high amounts in larva, decreasing amounts in pupa, increases throughout adulthood

in females: produces growth of new eggs
in males: stimulates sexual maturity
Term
how the body maintains blood sugar
Definition
pancreas: endocrine and exocrine gland that contains Islets of Langerhans
Islets of Langerhans: an oval collection of cells scattered through pancreas (1-2 million islets in a human pancreas)

blood from islets drains into hepatic portal vein directly into the liver
Term
Islets of Langerhans
Definition
cells in pancreas

three types of cells
1. Alpha cells: (20%) secrete glucagon
2: Beta cells: (75%) secrete insulin
3. Delta cells (1-8%)
Term
glucagon
Definition
small protein, binds to hepatocytes in liver

glucogenolysis: glucagon stimulates liver to break down glucogen into glucose
lipolysis: stimulates mobilization of fate stores
gluconeogenesis: stimulation of construction of glucose from non-carbohydrate resources (amino acids)

increased release of glucagon stimulated by low blood sugar and epinephrine/norepinephrine
decreased release of glucagon stimulated by insulin

glucagon is short-lived, is broken down by liver cells
Term
insulin
Definition
hormone

in liver:
1. suppresses glycogenolysis
2. stimulates glycogenesis
3. stimulates amino acid uptake and protein synthesis

in muscle
1. increases glucose uptake and glycogenesis

in all tissue
1. reduction in lipolysis
2. increased lipid uptake and fat synthesis
3. increased glucose uptake and glycogenesis

in kidney
1. increased glucose uptake in renal tubule

increased release stimulated by high blood sugar, glucagon, some amino acids, incretins
decreased release stimulated by low blood sugar
Term
Type I diabetes
Definition
loss of pancreatic beta-cell mass (unable to secrete insulin)
often referred to as juvenile diabetes
Term
Type II diabetes
Definition
defective signal reception, insulin resistance
often referred to as adult-onset diabetes
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