transmission of action potentials from one neuron to another. A chemical called acetylcholine is the neurotransmitter released from the presynaptic neuron. As the postsynaptic cells on the muscle cell membrane receive the acetylcholine‚ the channels for the cations sodium and potassium are opened. These cations produce a net depolarization of the cell membrane and this electrical signal travels along the muscle fibers. Through the movement of calcium ions‚ the muscle action potential is taken into actual
Premium Skeletal muscle Myosin Action potential
and (+) ions (Ca++) can pass into the muscle fiber which depolarizes the membrane potential. As this happens the voltage-gated sodium channels are triggered opens and allows sodium ions (NaCl-) enters the fiber and action potential spreads along the entire membrane to initiate excitation-contraction coupling. Following the depolorization of the membrane‚ repolarization occurs‚ which reestablishes the negative membrane potential. The ACh within the synaptic cleft is also degraded by AChE so that ACh
Premium Muscle Acetylcholine Neuromuscular junction
drop in voltage (refer to Figure 1)‚ therefore indicating that inside the muscle was more negative in relation to the outside solution. The time when the pipette was intramuscular‚ the recording showed a steady reading of the intramuscular voltage potential (Figure 1). When the pipette was removed from the crayfish muscle and was back in the extracellular solution‚ the voltage measurement returned to baseline (Figure 1). The intramuscular recordings showed that all three crayfish muscles were depolarized
Premium Chemistry Acid Potassium
patch-clamp electrophysiology‚ investigators have recently cloned‚ expressed‚ and characterized the genes encoding many of these proteins. Ion-channel proteins are under intense scrutiny in an effort to determine their roles in pathophysiology and as potential targets for drugs. Defective ion-channel proteins are responsible for cystic fibrosis‚1 the long-QT syndrome‚2 heritable hypertension (Liddle’s syndrome)‚3‚4 familial persistent hyperinsulinemic hypoglycemia of infancy‚5‚6 hereditary nephrolithiasis
Premium Action potential Cystic fibrosis
Chapter 48 Nervous Systems Lecture Outline Overview: Command and Control Center The human brain contains an estimated 1011 (100 billion) neurons. Each neuron may communicate with thousands of other neurons in complex information-processing circuits. Recently developed technologies can record brain activity from outside the skull. One technique is functional magnetic resonance imaging (fMRI)‚ which reconstructs a 3-D map of the subject’s brain activity. The results of brain imaging and other
Premium Neuron Action potential
Suggested answers to Practical Workbook for SBA Ch 1 Introducing biology Practical 1.1 Design an investigation of the effect of fresh pineapple on the setting of jelly Propose a hypothesis (p. 1-2) It is the fresh pineapple that causes the jelly to remain in liquid form. Design and perform an experiment (p. 1-2) 1 (Answer varies with Ss. The recommended quantity of jelly powder and water is stated on the packet of the jelly powder. Jelly will not set if it is too dilute.)
Premium Cell wall Enzyme Sodium chloride
the individual‚ (Waugh‚ A. and Grant‚ A.2010). Animal cell consists of a plasma membrane‚ separating the cells internal components from the extra cellular materials and external environment. Inside which are a number of organelles suspended in a watery fluid called cytoplasm. Cytoplasm includes the organelles and the inclusions. Organelles are highly specialized structures and often enclosed in their own membrane within the cytoplasm‚ specialised for specific activities. They include nucleus
Premium Cell Neuron Cell membrane
Key Terms Active transport: membrane proteins use cellular energy (usually ATP) to move molecules or ions across a plasma membrane against their concentration gradient. Allele: different forms of a gene • genotype – the combination of alleles in an organism. Aquaporin: a specialised channel protein in the plasma membrane of a cell‚ which is selectively permeable to water. Attachment protein: a protein in the plasma membrane of a cell that attaches either to the cytoskeleton inside the cell‚
Premium Cell membrane Cell
with many functional units or organelles (Spurger).A membrane is a fluid mosaic which consists of proteins‚ lipids and carbohydrates which seperates the cell from it’s surrounding environment or subdivides a cell into specialised regions or compartments (Watters). The membrane is specialised in that it contains the specific proteins and lipid components that it requires in order to fulfil the requirements needed by that organelle or cell. Membranes are vital for the integrity and function of a cell
Premium Cell membrane Protein Cell
Describe the pathways AND mechanisms by which water passes from the soil to the xylem vessels in the root. (7 marks) As there is a higher water potential in the soil‚ and there is a lower water potential in the root hair cells‚ the water molecules move from the area of high potential to the area of low potential. From the soil into the roots. The process by which the molecules of water move into the root hair cells is ’osmosis’. This is a passive process‚ meaning that no energy (in the form of
Premium Cell wall Plant physiology Xylem