Calcium ions then spread into the synaptic bulb, and Ach is released by vesicles into the synaptic cleft. Na+ ions go into the channels and K+ leaves. Na+ sets up action potential on the sarcolemma, and the muscle fiber is provoked. The action potential travels to the T tubules, and Ca2+ is released into the sarcoplasm. Ca2+ binds to the troponin, which results in a movement in the tropomyosin.
The breakdown of the membranes of these structures affect the function of the heart because the special calcium ATPase’s had stopped moving calcium from the cytosol into the endoplasmic reticulum of his cardiac muscle cells. As the intracellular calcium levels rose, they caused proteases to spill into the interior of the cell, attacking the cytoskeleton. Lysosomal enzymes normally bound safely inside vesicles begin to digest the plasma membranes of the organelles. Question D: Two important pieces of information—The instructions Joseph’s body needs to repair itself and his predisposition for vascular disease—are both contained within the cell on which structures? His predisposition for vascular disease is held in the Mitochondrial DNA.
5. The accumulation of sodium inside causes depolarization, which opens the calcium channels. 6. Influx of calcium triggers exocytosis of synaptic vesicles and liberation of neurotransmitter. 7.
Then a neurotransmitter, called acetylocholine (ACh), is released and the ACh binds to receptors on motor end plates and sodium ions then move into muscle fibers. The next step is the muscle action potentials move into the Ttubules where calcium is released by the sarcoplasmic reticulum and the calcium binds to a binding
adrenal medulla/adrenaline * Paracrine - that secretes hormones that affect adjacent cells e.g. gastric mucosa/gastrin/gastric pits. * Autocrine – regulate their own avtivity by the secretion of hoirmone e.g. interstitial cells of testis/testosterone Each target cell in the body is regulated only by those hormones to which it has receptor molecules , and not y others.different cells may respond in different ways to the same hormone – the transduction machinery of different target cells ‘reads’ the hormone signal in different ways. Blood hormone concentrationare usually governed by negative feedback control – a reduction in concentration stimulates additional secretion and an increase in concentration inhibits further secretion.
Voltage-gated K+ channels begin to open. d. Rapid Na+ entry depolarizes cell e. Na+ channels close and slower K+ channels open f. K+ moves from cell to extracellular fluid g. K+ channels remain open and additional K+ leaves the cell, hyperpolarizing it. h. Voltage-gated K+ channels close, less K+ leaks out of cell. i. Cell returns to resting ion permeability and resting membrane potential.
14 September 2012 Homework #2 1) A) The parts to a neuron are the cell body, bushy dendrite fibers, the axons, and the myelin sheath. B) Neural impulses are generated when a neuron fires an impulse called the action potential, which is a brief electrical charge that travels down the axon. The first part of the axon begins the process by opening up its gate, so that positively charged ions can flood through the cell membrane. As a result, this process depolarizes that axon section, causing another axon channel to open and then the process repeats continuously after the other. C) In terms of communication, nerve cells communicate with one another by having the dendrites receive the messages from other cells.
open | |What other tubular structure are they associated with? Sarcoplasmic reticulum | |What ion does this other tubular structure contain? Calcium ions | | Neuromuscular Interaction: | | neuromuscular junction: The site where the motor neuron and muscle fiber meet is the neuromuscular junction. | |The muscle fiber membrane forms a __motor __ __end_ _plate__ in which the sarcolemma is | |tightly folded and where nuclei and mitochondria are abundant. | |acetylcholine - neurotransmitter released from the __axon terminal___ of the neuron.
How would the breakdown of the membranes of these structures affect the function of Joseph’s heart cells? All intracellular organelles have membranes as part of their structure except ribosomes. The breakdown of these membranes affect the function of the heart because the lack of ATP has affected the plasma membrane pumps and stopped the moving of the ATPase calcium from the cytosol to the endoplasmic reticulum of the cardiac muscle. As the calcium level rice the protease spill into the interior of the cell which attacks the cytoskeleton, causing enzymes to eat away at the membranes. Queston D: Two important pieces of information-the instructions of Joseph’s body needs to repair itself and his predisposition for vascular disease- are both contained within the cell on which structures?
terest 11, How neurons communicate with other cells 1 to attract other electrical charges 2 leakage channels, voltage gated channel, ligand gated channel 3 only works for the ions LiceIC+ 4 action potential, graded potential 5 it will stop exchanging 6 it will decrease 7 they are sustained 8 cell membrane 9 voltages 12. All or none principle An action potential takes place in 2 phases: Depolarization: inside the membrane becomes + Repolarization : inside becomes more – Na+ and k+ are ions that move through the membrane via ion channels and change the electrical charge of the neuron - when NA+ channels open, NA+ moves inside= depolarization - When K+ channels open, K+ moves out + repolarization - When depolarization