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61 Cards in this Set
- Front
- Back
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Cell membrane functions |
Provides a physical barrier Regulates the exchange of ions, nutrients, elimination of waste Secretion of products with extracellular fluid Communication of cell and environment Provides structural support |
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Cell membrane electrical insulation role |
Cell membrane acts and insulator Cell interior has -1 charge and exterior +1 charge at rest The input of energy to transport ions across the membrane creates electrical gradient so the inside of the cell is negative to the outside |
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Cell membrane lipid types |
Phospholipid Glycolipid Cholesterol |
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Protein function |
Structural elements maintain cell shape and creates junctions to hold tissue together at cell level Enzymes catalyze reactions Receptors are specific for a particular molecule or family of molecules Transporters allow molecules to move in and out of cell |
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Carrier protein function |
Bind to substrate but never form direct connection between ICF and ECF Carry substrate across membrane by changing conformation or shape |
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Diffuse-best molecular characteristics |
Movement of molecules from higher to lower concentration until it eliminates the concentration gradient. Diffusion is passive, therefore no energy needed. |
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Structural protein function |
Maintain cell shape and creates junctions to hold together tissues at cell level |
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Diffusion effect on connection gradients |
Movement until equilibrium Flows rapid for short distance, slower over long distance Smaller moves faster Occurs faster at higher temp Occurs across open systems or through partitions |
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Fluid mosaic model structures |
Contains phospholipids, peripheral and integral proteins, glycolipids, glycoproteins, and cholesterol |
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Enzyme function |
Catalyze reactions |
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Glycoprotein main function |
Surface of cell, plays key role in body's immune system |
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Channel protein function |
Provides pores that allow molecules to pass through, gates opened or closed by proteins. Open channels-open most of time Gate- closed most of time |
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Diffusion |
Movement of molecules from higher to lower concentration until it eliminates the concentration gradient |
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Diffusion types |
Passive process (no energy needed) movement until equilibrium Rapid for short distances-slower over long distances |
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Facilitated diffusion |
Passive down concentration gradient (higher to lower concentrations) stops at equilibrium I.e. glucose in icf=ecf |
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Facilitated diffusion |
Stops at equilibrium I.e. glucose in ICF=ecf |
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Saturation define/describe |
Carriers working at max rate Further increase in substrate concentration has no effect |
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Exocytosis |
Export large lipophobic molecules I.e. proteins and waste left in lysosomes during intercellular digestion |
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Endocytosis |
Pinocytosis and potocytosis are examples Membrane indents Always taking place Energy input |
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Na+/K+ pump |
Sodium potassium pumps into cell at 3:2 ration with additional ATP Nerve cells use to transmit electricity by Na+ gradient - initiates electrical signal |
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Ion concentration level in ICF |
Potassium is in high concentration Sodium is low Calcium Ca key ion involved in intercellular signalling |
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ECF 2 divisions of/primary cations found |
Divided into plasma (liquid part of blood) and interstitial (bathes cells, outside circulatory system) Primary cation is sodium |
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Resting cell membrane |
Charge inside V outside Na+ ion concentration At rest, there are relatively more sodium ions outside the neurons and more potassium ion inside the neuron |
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Neuronal electrical signal initiation key ion |
Nerve cells use sodium potassium pump to transmit electicity by Na+ pump |
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Excitable tissue |
Ability to generate, propagate electrical signals, transmit stimuli, transmit information. -cations (+) attract anions (-), same charges repel each other |
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Na+ ion gated channel types |
Chemically gated Voltage gated Mechanically gated Sodium channels |
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Na+ ion gated channels functions |
Chem-controlled by intercellular messengers or extracellular ligands Voltage-controlled by electrical signals Mech-controlled by physical change Sodium-contains all gate types |
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Neuron-resting state..Change in ion permeability and results |
The input of energy to transport ions across the membrane creates an electrical gradient so the inside of the cell is negative to the outside |
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Signal molecules exhibit what characteristics |
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Specificity |
Ability of carrier to move only one molecule or group of closely related molecules |
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Competitive describe |
Move chemically different but similar substances by a carrier protein with one substance competing with the other based on affinity |
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Active transport vs facilitated diffusion |
Facilitated is passive with down concentration gradient (high to low). Active is protein mediated, needs energy, moves against concentration gradient |
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Hyposmotic/hyperosmotic |
Water movement. Hypo has more water, less solute. Hyper has more solute, less water |
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Cations...anions |
Cations-positive- attract anions-negative. And same charges repel each other |
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Gap junction |
Transfer chemical and electrical signals between cells by cytoplasmic bridges Channels are formed by connexins (proteins) When channels open, channels act as one. In mammals, found in most cells (heart muscles, some smooth muscle, lung, liver, neurons in brain) |
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Cell methods of communication |
Gap junctions, contact dependent, autocrine, and paracrine |
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Neurotransmitters and neurohormones release point and affected cells |
Hormones-chemical released into blood. Transmitter-chemical secreted by neurons that diffuse. Both affect only target cells |
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Target cells |
Cells that receive electrical or chemical signals such as hormones |
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Agonists |
Ligand that turns on receptor. May mimic a naturally occurring ligand. Used by many drugs. |
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Antagonist |
Blocks a receptors activity |
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Cell sensitivity/sensitivity to signal/determining factors and threshold |
Have receptor proteins that determine the cells response and allows for ligands to bind. If not present, cell will not respond |
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Chemical signalling |
Exhibits saturation (max out) Specificity of receptors Competitive between competing receptors |
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Protein kinoses |
Intracellular effector in chemical signalling |
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Lipophilic hormone function |
Signals diffuse into the phospholipid bylayer of cell membrane Bind to receptors in cytosol and nucleus Often turns on gene transcription |
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Ligand-regulated receptor molecules / channel types |
Ligand (gated ion channels) Receptor (enzymes G protein Integrin receptors |
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Secondary messengers |
Ions-Ca involved in intracellular signaling, binds to protein, altering function, producing response. Nucleotides-cAMP (activates protein kinase A), cGMP Lipid derived-IP3, DAG |
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Gene transcriptiom |
Transcription is copying of small section of DNA into RNA activated by G protein Link between a first messenger and second messenger to lipophobic signals |
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Homeostasis |
Process by which the body maintains a stable and optimal internal environment |
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Homeostasis regulation |
Adjust by physiological changes like body temp, glucose concentration, and fluid amounts |
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Homeostasis failure |
Disease occurs when it fails |
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Homeostasis control reflex 8 parts |
Stimulus-disturbance that starts reflex pathway Threshold-max stimulus needed to start reflex response Receptor-monitors environment Signal created- sent to integrating center (endocrine cell) Set point- desired value Effector- organ or gland that performs change to return to normal Physiological variables oscillate around set point Sensitivity-allowable distance from set point |
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Neurocrine |
(Long distance communication) chemical signal secreted by a nerve. Hormones affect only target cells. |
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Down regulation |
Used to bring target cells back to normal. May decrease receptor number. May decrease binding affinity |
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Autocrine |
(Allows communication between cells) chemical acts on cell that secreted it. (Acts locally) |
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Paracrine |
Secreted by cell to act on near by cells. (Allows communication between cells.) (acts locally) |
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Intracellular signaling key ion |
Ca in key ion involved. Binds to protein, altering it's function, producing a response |
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Target cells receptor function |
Binds to receptors in cytosol and nucleus. Often turns on gene transcription. |
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Competitive inhibitor |
Enzyme inhibition where binding of the inhibitor to the active site on enzyme prevents binding to substrate and vice versa. Must bind reversibly to active site of enzyme |
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Calmodulin |
Ca binding protein that alters enzyme activity on open state of ion channels. |
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Nitric oxide |
Does not require a receptor |
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Calcium sources ECF/ICF |
Enter cytosol through ECF through channels or ICF by secondary messengers |
