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Physiology Chp5-8
Chemical messenger, endocrine system, nerve cells, synaptic transmission
103
Physiology
Undergraduate 3
10/25/2010

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Term
Receptor
Definition
Proteins on a target cell tjat recoginizes and binds a chemical messenge; in sensory systems, detectors of stimuli
Term
Affinity
Definition
A measure of how tightly ligand molecules bind to proteins( strength of binding between a messenger and receptor)
Term
Ligand
Definition
A chemical messenger
Term
Signal Transduction
Definition
How a chemical signal is translated into a cell action
Term
Chemical Messenger(F): Neurotransmitter
Definition
Chemical messenger released from the axon terminal of a neuron (a messenger produced by neurons released from the ECF of the synaptic cleft). Ex. Glycine
Term
Chemical Messenger(F): Hormone
Definition
Messenger produced by endocrine cell secreted into blood via interstitial fluid. Ex:Insulin and Estrogen
Special Class-Neurohormones, ex:ADH
Term
Half-Life
Definition
Time for a chemical to decrease concentration in half(interstitial or blood)-(dissolved=short) (bound=long)
Term
Up-regulation
Definition
Receptor number increase on target. May result in too little messenger. Sensitivity to messenger increase.
Term
Down-regulation
Definition
Receptor numbers decrease on target. May result from excess messenger. Sensitivity to messenger decrease. Tolerance to messenger develop.
Term
Agonist
Definition
Chemcial which bind to receptors. Action mimic normal response.(Activation)
Term
Antagonist
Definition
Chemical that binds to a receptor but does not result in a response. Competes with normal ligands. Opposite of agonist.(no activation)
Term
Second Messenger
Definition
Binding of first messenger to receptor lead to production of second messenger. Involves: Gi-activates amplifier enzyme, Gs-imhibits amplifier enzyme
Term
Chemical Messenger(F):Paracrine
Definition
chemicals that serve to signal nearby cells. Ex: Histamine
Autocrine-subclass that acts on the same cell that secreted them.
Term
Chemical Messenger(C): Amino Acids
Definition
Lipophobic, target cell receptors on a membrane.Only four function as a messenger, but all are neurotransmitters.
Ex. GABA, glutamate, aspartate, glycine
Term
Chemical Messenger(C): Amine
Definition
Most are lipophobic except thyroid hormones. Derived from amino acid and contain amine groups. Ex: Catecholamine
Term
Chemical Messengers(C):Peptide/protein
Definition
Most abundant ligand; lipophobic. Made of chain of amino acids. Peptide<50a.a. and protein>50a.a.
Term
Chemical Messenger(C): Steroid
Definition
Lipophilic; target has intercellular receptors. Derived from cholesterol and function as hormones
Term
Chemical Messenger(C): Eicosanoid
Definition
Lipophilic; intercellular target receptors. Derived from arachidonic acid(phospholipid)
Term
Lipophobic
Definition
Water soluble not lipid soluble. Does not easily cross cell membrane. May require pumps or channels. General action of target response: enzyme activation, membrane permeability changes. Syn independent, Stored in vesicles until needed, Exocytosis
Term
Lipophilic
Definition
Lipid soluble not water soluble. Easily crosses cell membrane. Receptor location with in cell.General action of target response is gene activation. Syn on demand, release immediately, and release rate depends on syn.
Term
Target Cell Response
Definition
One messenger=many receptor, one target=many types of receptors. Strength of response depends on: concentration, #of receptors per target, and receptor affinity.
Term
Ligand-gated channels: Channel-linked receptor
Definition
Fast ligand-gated channel. Receptor and channel are the same protein. Binding of ligand causes channels to open and close. Change in transport of ions cause target response. Action is direct.
Term
Ligand-gated channel: Enzyme-linked receptor
Definition
Receptor and enzyme=same protein. Ligand binding activates enzyme which cause target response. Action is direct.
Term
Ligand-gated channel:G-protein-linked receptor
Definition
Slow ligand-gated channel. Receptor and channel=different protein but are linked by g proteins. Binding of ligands activated G which activates channels. Change in transport ions cause target response. Action is indirect.
Term
Second Messenger 5 types
Definition
cAMP, cGMP, IP3, DAG, and calcium ions( Table 5.3)
Term
Signal Amplification
Definition
"a little does alot". Small amount of ligands can cause a huge response in targets. Each step recruits more participants. Similar to second messenger.
Term
Primary endocrine organs: Pineal Gland
Definition
Glandular tissue that secretes hormone melatonin. Also may be involved in circadian rhythm.
Term
Primary endocrine organ: Thymus
Definition
Secretes Thymosin and also regulates T cell function
Term
Primary endocrine organs: Parathyroid Hormones
Definition
Regulate calcium level in the blood
Term
Primary endocrine organs: Thyroid glands
Definition
Two types T3and T4. Regulates metabolism. Calcitonin-regulates calcium level in blood also.
Term
Primary endocrine organs: Adrenal glands
Definition
Mineralocorticoid(aldosterone)- secreted from zonae glomerulosa, regulates Na and K levels.
Glucocorticoids(cortisol)-secreted from zonae facciculata and reticularis, regualates body's response to stress and metabolism.
Sex hormones(androgen)-secreted from zonae facciculata and reticularis,regulates reproduction functions
Term
Primary endocrine organs: Adrenal medulla
Definition
Secretory cells: chromaffin cell, under neutral control
Term
Primary endocrine organs: Exocrine Pancreas
Definition
Acinar and duct cells: Secretes fluid and enzymes. Secretion enters digestive tract via pancreatic ducts
Term
Primary endocrine organs: Endocrine pancreas
Definition
Islet of Langerhan: Alpha cell-glucogen, Beta cells-insulin, delta cells-somatostatin and fcells-pancreatic poypeptides.
Term
Primary endocrine organs-Gonads
Definition
Males(testes):Testosterone and Androstenedione Females(overies)-Estradiol, Progesterone, and Placenta of pregnant female.
Term
Secondary endocrine organ:Heart
Definition
Atrial natriuretic peptide(ANP)
Term
Secondary endocrine organ: Kidney
Definition
Erythropoietin
Term
Secondary endocrine organ: Gastrointestinal tract
Definition
Secretin, cholecystokinin, and gastrin
Term
Secondary endocrine organ: Liver
Definition
Insulin-like growth factor(IGFs)
Term
Secondary endocrine organ:Skin and Kidney
Definition
Calcitriol
Term
Primary endocrine organ:hypothalamus
Definition
release inhibiting hormones. Regulates secretion of anterior pituitary hormones
Term
Primary endocrine organ:Pituitary gland-Posterior
Definition
ADH-water balance and osmolarity(paraventricular nucleus)
Oxytocin-milk ejection (supraoptic nucleus)
Term
Three factors affecting hormone levels in blood
Definition
Rate of hormone secretion, amount of hormone bound to plasma protein, and hormone metabolism
Term
Primary and Secondary hypersecretion and hyposecretion
Definition
Hyper=too much, hypo=too little. Primary-abnormality in endocrine organs secreting hormones. Secondary-Abnormality in tropic hormone(hypothalamic and anterior pituitary tropic hormones)
Term
Hormone interaction: Antagonistic
Definition
Effect of hormones oppose each other.Ex: glucogen increase blood glucose level and insulin decrease.
Term
Hormone interaction: Additive
Definition
Net effect equals sum of individual effect
Term
Hormone interaction:Synergism
Definition
Effect of two hormones favor each other but the net effect exceeds the sum of individual effect. Ex: glucagon
Term
Hormone interaction: Permissive
Definition
One hormone needed for the other to exert its effects
Term
Electrical Synapse
Definition
Two neurons linked together by gap junction. Function in nervous system
Term
Chemical Synapse
Definition
Functional anatomy of chemical synapse, signal tranduction, excitatory and Inhibitory
Term
Effector organ
Definition
Performs functions in response to commands from neurons; are usually muscles and glands.
Term
Neuroeffector junction
Definition
The synapse between a motor neuron and skeletal muscle cell
Term
Pre-synaptic neuron
Definition
A neuron that transmits signals to a second neuron or and effector cell
Term
synaptic cleft
Definition
the extracellular space between the axon terminal of the presynaptic cell and the postsynaptic cell at a synapse
Term
Postsynaptic neuron
Definition
the neuron that receives signals from another neuron
Term
Synapse
Definition
Axodendritic, Axosomatic, and Axoaxonic
Term
Convergence
Definition
the transmission of information from two or more neurons to one cell
Term
Divergence
Definition
The axon of one neuron often has several collaterals that communicate to several other neurons
Term
Excitatory
Definition
More likely to produce an action potential-depolarization
Term
Inhibitory
Definition
Less likely to produce action potential- Hyperpolarization;membrane stability
Term
90% of the CNS is composed of?
Definition
Glial Cells
Term
Glial Cell: Astrocyte
Definition
numerous Functions
Term
Glial Cell: Ependymal
Definition
Lines cavities
Term
Glial Cell: Microglia
Definition
protects CNS from foreign matter through phagocytes. Also it protects CNS from oxidative stress
Term
Glial Cell: Oligodendrocytes
Definition
forms myelin
Term
Glial Cell: Schwann Cells
Definition
form myelin
Term
Astrocytes
Definition
development of neutral connection, modulate synaptic activities, and removes neurotransmitters from synaptic cleft.
Term
Astrocytes
Definition
Communicate to neurons through chemical messengers, maintain normal electrolyte composition of ICF, and protects neurons aganist toxic substances/oxidative stress
Term
Cerebrospinal Fliud(CSF)
Definition
secreted by ependymal cells of the choroid plexus which circulates to subarachnoid space and ventricle; reasorbed by arachnoid villi
Term
CSF: Funtions
Definition
1) Cushions Brain
2) Maintain interstitial fluid environment
3) total volume 125-50mL(recycled 3times day)
Term
Blood supply
Definition
1)CNS comprises 2% of body weight
2)High metabolic rate
3)Depends on blood flow for energy
Term
Stroke
Definition
Caused by decreased blood supply
Term
Blood-Brain Barrier: Capillaries
Definition
Sites of exchange between blood and interstitial fluid
Term
Blood-Brain Barrier
Definition
Special anatomy of CNS capillaries which limits exchange
Term
White Matter: Projection Fiber
Definition
Cerebral cortex with lower levels of brain or spinal cord
Term
White Matter: Association Fiber
Definition
connect to areas of cerebral cortex on same side of brain
Term
White Matter: Commissural fibers
Definition
Connects same cortical region on two sides of the brain
Term
White Matter: Corpus Callosum
Definition
primary location of commissural fibers
Term
Dermatome
Definition
Sensory region of skin, each served by spinal nerves
Term
Gray Matter: functional halves
Definition
Dorsal: sensory functions
Ventral: motor functions
Term
White matter forms:
Definition
tracts-ascending and decending
Term
Cerebellum
Definition
1)Bilaterally symmetrical
2)Cortex and nuclei
Term
Cerebellum: Functions
Definition
1)Motor coordination and balance
2)Coordination of eye and body movement
Term
mixed nerve:
Definition
contain both afferent and efferent axon
Term
Ascending tract:
Definition
transmit info from spinal cord to brain
Term
Descending tract:
Definition
transmit info from brain to spinal cord
Term
Contralateral pathway-
Definition
when a pathway crosses to the side opposite its origin
Term
Reflex:
Definition
Automatic patterned response to a stimulus
Term
Olfaction depends on...?
Definition
chemicals in the air which binds to chemoreceptors in Olfactory epithelium
Term
Olfactory epithelium is located in the...?
Definition
Nasal cavity
Term
Supporting cell
Definition
Secretes mucus
Term
Basal Cell:
Definition
are precursors for the development for new receptors
Term
Receptor cell:
Definition
neurons that respond to odorants
Term
Sustentacular cells:
Definition
maintain the extracellular environment surrounding the receptor cells
Term
Bowman's gland:
Definition
produces the mucus found in the nasal cavity and olfactory neuron axons.
Term
Cilia
Definition
contains receptors that bind with specific odorant molecules.These cilia are immotile and increase SA
Term
AXON of olfactory receptor:
Definition
enter the CNS through holes(foramina) in the cribriform plate of the skull and terminate in the olfactory bulb.
Term
Cilia projected into mucus:
Definition
have chemoreceptors
Term
Olfactory binding proteins are located in the...?
Definition
Mucus
Term
Olfactory binding proteins transport odorants to?
Definition
Receptors
Term
Cribriform plate:
Definition
Base of skull with holes through which axons of receptor cells can travel
Term
Binding of an odorant molecule to a membrane receptor activates:
Definition
a G protein called G-olf
Term
G-olf activates the enzyme:
Definition
adenylate cyclase
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