You will eventually have to get back to the resting potential involving the

You will eventually have to get back to the resting

This preview shows page 4 - 7 out of 8 pages.

You will eventually have to get back to the resting potential, involving the sodium-potassium pump. The cell is polarized at -70mv. Sodium comes in through depolarization. The process of the potassium channel opening and all the events that follow is called repolarization. Three sodium to two potassium ratio.
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Microvilli, Cilia, and Flagella microvilli: extensions of the plasma membrane that serve primarily to increase a cell’s surface area; best developed in cells specialized for absorption such as the epithelial cells of the intestines and kidney tubules cilia: hairlike processes about 7-10 µm long; sensory, serving as the cells “antenna” for monitoring nearby conditions; sense of balance; monitor the flow of fluids as it is processed to urine flagellum: whiplike tail of a sperm Neurotransmitters neurotransmitter: chemical released at the distal end of an axon that stimulates and adjacent cell examples: acetylcholine (ACH), norepinephrine, and serotonin action/graded potential steps (take 1/1000 th of a second to do): ACH makes peripheral protein move out of the way so the gate can open sodium comes in; as it comes in -70mv gets closer to 0 sodium keeps coming in until -70mv reaches +30mv; then the gate closes and the ACH is destroyed (depolarization) because it reaches +30mv, voltage disruption makes a peripheral protein move off the potassium channel and potassium exits the cell until it reaches -90mv (hyperpolarization) to get back to -70mv a pumper molecule will pump 3 sodium to 2 potassium The Nucleus largest organelle of the cell and visible with the light microscope contains the cell’s chromosomes and is the genetic control center of cellular activity a few cell types are multinucleate, they have 2 to 50 nuclei nuclear envelope: formed by two unit membranes surrounding the nucleus and is perforated with nuclear pores, formed by a ring of proteins nuclear lamina: narrow, but dense fibrous zone inside the nuclear envelope nucleoplasm: material inside the nucleus chromatin: fine thread-like matter composed of DNA and protein nucleoli: dark-staining mass where ribosomes are produced Endoplasmic Reticulum (ER) literally means “little network within the cytoplasm”
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endoplasmic reticulum: system of interconnected channels called cisternae enclosed by a unit membrane made to compartmentalize synthesizes steroid & other lipids, detoxifies alcohol and other drugs, and manufactures all membranes of the cell rough endoplasmic reticulum cisternae are parallel, flattened sacs covered with granules called ribosomes continuous with the outer membrane of the nuclear envelope, and adjacent cisternae are connected by perpendicular bridges produces the phospholipids and proteins of plasma membrane & synthesizes proteins that are either packaged in other organelles or secreted from the cell abundant in cells that synthesize large amount of protein (digestive gland) smooth endoplasmic reticulum
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