Search results
Results from the WOW.Com Content Network
Prickles on a blackberry branch. In plant morphology, thorns, spines, and prickles, and in general spinose structures (sometimes called spinose teeth or spinose apical processes), are hard, rigid extensions or modifications of leaves, roots, stems, or buds with sharp, stiff ends, and generally serve the same function: physically defending plants against herbivory.
Dendritic spines serve as a storage site for synaptic strength and help transmit electrical signals to the neuron's cell body. Most spines have a bulbous head (the spine head), and a thin neck that connects the head of the spine to the shaft of the dendrite. The dendrites of a single neuron can contain hundreds to thousands of spines.
Prickles, thorns and spines are all modified plant tissues that have evolved to prevent or limit herbivory, these structures have evolved independently a number of times. [215] Stimulant toxins: plants which are only distantly related to each other, such as coffee and tea, produce caffeine to deter predators. [216]
Prickles and thorns are an evolved defense against herbivores — animals that eat plants — and can also aid in growth, plant competition and water retention, according to the study.
A dendrite (from Greek δένδρον déndron, "tree") or dendron is a branched cytoplasmic process that extends from a nerve cell that propagates the electrochemical stimulation received from other neural cells to the cell body, or soma, of the neuron from which the dendrites project.
Dendritic filopodia may be the site of synapses in certain regions of the nervous system. In some neuronal cell types, such as in rat retinal ganglion cells, dendritic spines are not present, suggesting that in these cases, synaptogenesis occurs primarily on dendritic shafts or on filopodia themselves.
Cell damage (also known as cell injury) is a variety of changes of stress that a cell suffers due to external as well as internal environmental changes. Amongst other causes, this can be due to physical, chemical, infectious, biological, nutritional or immunological factors. Cell damage can be reversible or irreversible.
Viburnum lesquereuxii leaf with insect damage; Dakota Sandstone (Cretaceous) of Ellsworth County, Kansas. Scale bar is 10 mm. Knowledge of herbivory in geological time comes from three sources: fossilized plants, which may preserve evidence of defense (such as spines) or herbivory-related damage; the observation of plant debris in fossilised animal feces; and the structure of herbivore mouthparts.