Nervous tissue. Nervous tissue or nerve tissue is the main tissue component of the two parts of the nervous system; the brain and spinal cord of the central nervous system (CNS), and the branching peripheral nerves of the peripheral nervous system (PNS), which regulates and controls bodily functions and activity.
Transmission. Mosquitoes carry the parasite that causes heartworm disease from animal to animal. The life cycle of a heartworm begins when a mosquito bites an infected animal carrying heartworm microfilariae in its blood.If that mosquito bites another cat or dog, it transmits the larvae to that animal.The larvae mature into adult worms in the heart and lungs of the host animal.he life cycle of a heartworm begins when a mosquito bites an infected animal carrying heartworm microfilariae in its blood. If that mosquito bites another cat or dog, it transmits the larvae to that animal. The larvae mature into adult worms in the heart and lungs of the host animal.
In the southern United States, especially the Gulf Coast and Florida, where mosquitoes are present year-round, the threat of heartworm disease is constant.Figure 1. Distribution of dog heartworm in the United States.Credit: American Heartworm Society.evelopment of heartworm in the vector starts when microfilariae are ingested by the female mosquito during blood feeding on an infected dog. Microfilariae leave the midgut of the mosquito soon after ingestion and migrate into the Malpighian tubule cells (the mosquito kidney).