Exam 5 Flashcards
What is another name for the autonomic system?
Visceral nervous system
Autonomic nervous system
efferent innervation of tissues other than skeletal muscle, some examples are cardiac and smooth muscle, adipocytes, and glands
What is the difference between somatic and autonomic nervous systems?
somatic controls voluntary while autonomic control involuntary
What is the difference between somatic neuron and visceral neurons?
somatic neuron is single, long axon, excitatory while visceral neurons are pre and post synaptic neurons, excitatory or inhibitory
Ganglion
postsynaptic neuron that has its cell body in the ganglion that will continue onto the target tissue
Preganglionic neuron
presynaptic neuron sends message to ganglion
What are the two divisions of the ANS?
sympathetic (fight or flight) and parasympathetic (rest and digest)
Dual innervation
every organ receives input from both sympathetic and parasympathetic divisions
Sympathetic division
preganglionic neuron - originate entirely of the CNS (thoracic to lumbar), postganglionic neuron - trunks span from cervical to sacral
What is the 3 categories of sympathetic postganglionic neurons?
sympathetic chain, collateral ganglia, and adrenal
Sympathetic chain
majority of the postsynaptic fibers originate in this region, directly adjacent to the spinal cord on both sides (symmetrical), insert into organs/glands of head, heart, lungs
Collateral ganglia
preganglionic neurons come through both ventral roots, regulating functions of digestive system and reproductive system, located on ventral surface
What are the types of the collateral ganglia?
celiac, superior mesenteric, inferior mesenteric
Adrenal medulla
post ganglionic neurons are endocrine tissue not neurons, inner layer, contains chromaffin cells
Adrenal cortex
true endocrine tissue, outermost layer
Chromaffin cells
endocrine cells that are regulated by the nervous system, releases secretions (epinephrine and norepinephrine) into the bloodstream
Where do the preganglionic cell bodies originate in the parasympathetic division?
cranial nerves - oculomotor, facial, glossopharyngeal, vagus, spinal cord - S2, S3, S4
What is the autonomic function of the cranial nerves?
oculomotor - control tear ducts (auto-lacrimal cells), facial - produce saliva, glossopharyngeal - regulate saliva production, vagus - “the wonderer”
Parasympathetic innervation
preganglionic axons pass to peripheral ganglia within target organs, preganglionic neurons are long and myelinated while postganglionic neurons are short and typically unmyelinated
What is the physiology of “fight or flight”?
increased heart rate, sweating, constrict blood flow in GI and urinary system, dilate blood flow around skeletal muscle, increased respiration rate, dilation of airways
How is the sympathetic division able to be systemic?
able to activate lots of neurons because the Adrenal medulla is activated since lot of epinephrine is released into the bloodstream to activate all those regions
What is the physiology of “rest and relax”?
decreased heart rate, increased GI activity, dilate blood blow around GI, decrease respiration rate, always constricted
How is the parasympathetic division able to be systemic?
it is like a reset button, does not rely on the endocrine system, not organized for mass discharge
Cholinergic neurons
acetylcholine is released, all preganglionic neurons in both divisions are this, postganglionic neurons of parasympathetic division are this too
Adrenergic neurons
epinephrine and norepinephrine is released, postganglionic neurons in sympathetic division are this, adrenal chromaffin cells are this too
What are the different types of acetylcholine receptors?
nicotinic and muscarinic
Nicotinic
activated by nicotine and acetylcholine, ionotrophic - ion gated ligand channels, motor end plate is an example, found on dendrites in both divisions
Muscarinic
activated by acetylcholine and muscarine, metabotrophic - associated with signaling enzymes, only on target organs of parasympathetic division
Adrenergic neurons
in sympathetic division, activated by epinephrine or norepinephrine, one of reasons why there is diversity during fight or flight response
Why can parasympathetic and sympathetic division can produce opposite responses?
they have different neurotransmitters that can activate different types of receptors
Why can the sympathetic nervous system can sometimes activate responses on the same tissue type?
some regions would have alpha adrenergic receptors which activates the target tissue then some regions have beta adrenergic receptors which inhibits the target tissue
Antagonistic control
not mutually exclusive - can work alone or work simultaneously to control normal function, dual innervation of body tissues leads to this
Tone
balance of basal activity, most organs have tone not just muscles, determined by the autonomic system
Endocrine system
a chemical messenger within the body, coordinate many processes within the body by effecting changes at the cellular level, decentralized
What is the differences between endocrine system and nervous system?
nervous - one cell to one cell, generally localized signals, short duration, rapid recovery, endocrine - one cell to many cells, global effects, long duration, long recovery
Neuroendocrine tissue
secreted directly from neurons into the bloodstream, examples are chromaffin cells of adrenal medulla and hypothalamus
Processes under hormonal control
metabolism, vascular function, reproduction, cell growth, cell differentiation, behavior
How are hormones classified?
origin, structure, and function
What are the structural hormone classification?
peptide, steroid, amine
Peptide hormones
proteins, genetically encoded, translated in an inactive form known as preprohormone, then the cells uses proteolytic enzymes to produce smaller yet inactive enzymes called pro hormones, then are cleaved to produce an active hormone
Steroid hormone
possess cholesterol backbone, sex steroids, cortical steroids, all have 4 fused carbon rings but the R groups differ on each hormone
Steroid hormone synthesis
Cellular enzymes modify cholesterol to produce different biologically active hormones, it is complicated and always starts with cholesterol
What can testosterone be converted to and with what?
DHT with 5 alpha reductase
What does testosterone do? And what does DHT do?
drives some secondary sex characteristics, DHT leads to male pattern baldness
Amine hormones
derived from single amino acids - tyrosine and tryptophan
What does tyrosine make?
epinephrine, norepinephrine, dopamine, and thyroid hormones
What does tryptophan make?
used by the pineal gland in the hypothalamus to create melatonin which is important for regulating sleep and wake cycles which can produce then serotonin
Hormone mechanisms
all hormones require receptors to work, known as first messengers, receptor upregulation or downregulation
Receptor upregulation
increase sensitivity, tissue places more receptors on the cell surface
Receptor downregulation
decreases sensitivity, tissue removes receptors on the plasma membrane
How does solubility affect hormone transport?
solubility of a hormone in the plasma predicts transport mechanisms and half life
Water-soluble hormones
do not require carrier proteins and can just be dissolved in water, shorter half life, extracellular receptors, secondary messenger receptor, examples are peptide and most amine hormones
Lipid hormones
insoluble in plasma and requires a carrier protein, lipids have longer half life, intracellular receptors, gene transcription, examples are steroids and thyroid hormone
Estrogen
lipophilic, located inside the cell and when it passes through the plasma membrane and binds to the estrogen receptor then will get translocated inside the cell to then influence gene transcription
What is the link between estrogen and beast cancer?
can be caused due to how estrogen can drive cell growth and proliferation, best practice for someone who has been diagnosed is genotyping, single positive means the estrogen pathway is working
What hormone are being tested for if someone has breast cancer?
estrogen and progesterone
What is the final step to making estrogen?
aromatase which causes treatments of breast cancer be inhibitors of aromatase
What are examples of secondary messenger system?
adrenergic and muscarinic receptors
Metabotropic receptors
second messengers are intracellular enzymes activated by an extracellular receptor
Advantage of secondary messenger system
once an enzyme is activated, it can activate more then more so a single binding event may result in 1,000,000 final products
Glycogen metabolism
stores away glucose so when body is fasting glycogen needs to be broken down into glucose
First messenger of glycogen metabolism
one epinephrine molecule binding receptor on liver cell membrane
Second messenger of glycogen metabolism
amplification of several intracellular enzymes, activates protein kinase A
What is the effect of the glycogen metabolism?
1,000,000 glucose molecules released from glycogen storage
What is the effect of protein kinase A?
stops the cell from making new glycogen, initiate the process of glycogen breakdown by adding functional groups to glycogen which causes it to lose stability and get converted into glucose
G-protein coupled receptors
consist of three subunits which are alpha, beta, and gamma, when the hormones binds to the receptor, the alpha subunit separates from beta and gamma
Different forms of alpha subunit
GaS, GaI, GaQ
Kinases
carry out phosphorylation
Phosphorylation
may dictate protein shape, activity, stability, binding partners or localization, occurs on specific amino acids residues (serine, threonine, tysosine)
Tyrosine kinases
not G-protein mediated, kinase directly coupled to receptor, may involve fewer steps than GPCR pathways
Chronic myeloid leukemia
a cancer that is very fast growing, caused by the fusion of BCR and APL that is active without hormone to turn on the kinase, drive cell growth and proliferation as long the protein is there
Gleevec
generic name is imatinib, treatment for CML, and would go into remission within a week, magic bullet, blocks the active site and prevents the kinase from phosphorylating,
The problem with Gleevec
receptor tyrosine kinase tend to mutate as the cancer grows, this really effective drug is no longer effective a couple of generations later because the receptor has mutated
How is calcium regulated? (ion)
PTH/calcitonin
How is glucose regulated? (organic nutrient)
insulin (help cells take up glucose)
Neurotransmitter activation
done by epinephrine
Factors influencing release of hormones
not mutually exclusive
Parathyroid hormone (PTH)
secreted by parathyroid, raises plasma calcium, causes more reabsorption of calcium through kidneys, causes the kidneys to release calcitriol
Calcitonin
secreted by thyroid, lower plasma calcium, simulates the kidneys to start excreting more calcium which means calcium would leave the body through urine
Calcitriol
hormone that acts on the GI tract to help us absorb as much as calcium as possible from digestive system
What is the fastest hormone for releasing fatty acids?
epinephrine and thyroid hormone
What effects do hormones have on each other?
hormones may modulate effect of other hormones, usually through receptors, regulating the synthesis and secretion of other hormones
Permissiveness
upregulation the sensitivity of that hormone in a particular tissue, synthesis of adrenergic receptors, increase of sympathetic response
Pituitary gland
major regulator of peripheral hormone release, anterior pituitary and posterior pituitary
Anterior pituitary
also known as adenohypophysis, typical endocrine gland structure, is made up of epithelial tissue and that secretes hormones
Posterior pituitary
also known as neurohypophysis, made up of nervous tissue, neuroendocrine - neurons secrete hormones into the bloodstream
What is the pituitary regulated by?
hypothalamus
Where are the cell bodies of the posterior pituitary located?
supraoptic region and paraventricular nuclei which are in the hypothalamus
What are the hormones of the posterior pituitary? And their function?
Oxytocin - producing contraction in smooth muscle and milk letdown, ADH (Vasopressin) - water regulation
ADH (Vasopressin)
takes water from fluid that is about to become urine, ADH is released into the collecting duct that has the fluid, filtrate (filtrated blood) then aquaporins inserted into the tubule which allow more water to be reabsorbed into a capillary so less water will be in the urine
Oxytocin
involved in milk letdown in breast feeding, thinking about the baby or hearing the baby cry cause oxytocin to be released so stored milk will be released to the baby breast feeding, oxytocin is released to enhance uterus contraction and continue to stretch the cervix, is also released in the presence of a partner (romance hormone) or pet
How do the hypothalamus regulate the anterior pituitary?
tuberal region contains neurons that secrete hormone into the capillary bed then flows into the veins then another capillary bed, stimulate the releasing and inhibiting hormones, uses a vascular network which is a hypophyseal portal system
Tropic hormones
hormones that go from the anterior pituitary to endocrine tissue in the body
What are the types of feedback loops?
ultra short loop - releasing hormone on hypothalamus, short loop - tropic hormone on hypothalamus (GH on GHRH), long loop - effector hormone on hypothalamus and anterior pituitary (IGF on GHRH+GH)
What is the difference and similarities between prolactin and oxytocin?
prolactin - regulate milk synthesis, oxytocin - regulates milk let down, both are a positive feedback loop
Growth hormone
released by the anterior pituitary
What is growth hormone regulated by?
growth hormone releasing hormone (GHRH) and growth hormone inhibiting hormone (GHIH)
Why is growth hormone releasing hormone released?
low plasma glucose, raised plasma arginine, exercise, sleep, fasting
Effects of growth hormone
effector functions - metabolic (increase nutrients for ATP synthesis), tropic functions - released to the liver which then releases somatomedins (amino acid uptake, protein synthesis, cell growth and proliferation)
What are the disorders associated with GH?
hyposecretion which results in dwarfism, hypersecretion which results in gigantism and acromegaly (in adults with epiphyseal line, bone growth in width)
Why is hyposecretion caused?
genes, tumors, high levels of stress
Gross anatomy and microscopic anatomy of thyroid gland
follicles, colloid, follicular cells (thyroid hormone), and parafollicular cells (calcitonin)
Thyroid follicle
secretary and functional unit of the thyroid gland, consists of thyroid endothelial cells that surround a central colloid-filled cavity. the membrane polarity is apical which faces lumen and basal which faces blood, blood supply is capillary plexus
TSH receptor
G coupled protein receptor which stimulates thyroglobulin synthesis which is a protein that forms in the colloid
How is iodine used in the cell?
transported in the bloodstream then this symporter (secondary active transport) captures the iodine and sodium and moves the iodine through an enzyme thyroid peroxidase and moved into the colloid then the iodine is attached to the tyrosine on the thyroglobulin
Monoiodotyrosine
one iodine on the tyrosine
Diiodotyrosine
two iodines on the tyrosine
What are the thyroid hormones called?
T3 (attach monoiodotyrosine to diiodotyrosine) and T4 (two diiodotyrosine together)
How are thyroid hormones secreted?
the hormones go through pinocytosis through the follicular cells then proteolytic enzymes will start to break down the chain and start to secrete the T3 and T4 into the bloodstream, they are lipid soluble so it uses TBG to be carried in the bloodstream
Thyroid simulating hormone (TSH)
simulates all steps of thyroid hormone synthesis (by cAMP increase), biological effects include gene transcription and the production of Na+/I+ symporter, thyroglobulin, thyroid peroxidase, and thyroid hormones
Why are two different versions of thyroid hormone made?
have a similar effect, at the target tissue T4 becomes T3 by deiodinases because T3 is more potent even though T4 is more abundant
What is given during nuclear fallout?
a medicine containing iodine in low concentration which blocks the radiation with potassium that is easier to digest so they hope your body would compete with the radioactive iodine with the medicine one
Intracellular effect of thyroid hormone
increasing transcription of Na/K ATPase (increase oxygen consumption), increased protein synthesis, glycogen breakdown, fatty acid oxidation, and creating glucose from noncarbohydrate sources (growth and differentiation in conjunction with GH), enhanced cholesterol synthesis (LDL regulation)
Calorigenic effect
increase basal metabolic rate and heat production
What is required for skeletal and CNS development?
regulator of tissue growth and development
How is thyroid hormone regulated?
uses negative feedback loop with thyroid hormone levels if there is too much or too little, body temperature - even if it is cold TRH is secreted until the body temperature is up
Hypothyroidism in infants
shortage of iodine, big effect, cretinism - short, disproportionate body, mental impairments (due to CNS impairments)
Hypothyroidism in adults
low basal metabolic rate, dermal edema, cold intolerance, lethargy, mental sluggishness, myxedema (appearance very much changes)
How is hypothyroidism caused?
tertiary - disease in hypothalamus, secondary - disease in pituitary, primary - disease in thyroid
Goiter
thyroid dysfunction that causes abnormal enlargement of thyroid gland, maybe caused by iodine deficiency, tropic hormones stimulate and cause gland growth since feedback loop cannot be stopped
Grave’s disease
abnormal development of antibodies in the thyroid gland that cause hyperthyroidism, symptoms includes elevated basal metabolic rate, irregular rapid heartbeat, nervousness, weight loss, bulging eyes, autoimmune
