<span>Superior and inferior vena cava enters the right atrium which is pumped by the tricuspid valve to the right ventricle and to the pulmonary valve to the pulmonary artery then to the lungs from the lungs back thru the pulmonary veins entering the left atrium pumped by the mitral valve to the left ventricle to the aortic valve to the aorta.
The circulatory system is important in meeting the needs of all cells in the body because it offers means of transport by which cells obtain the materials needed to live and function.</span>
A single undifferentiated cell. For example, in human, this was the embryo.
Answer:
The physical space between the presynaptic and postsynaptic neurons is called the synaptic cleft
and the chemical that is released to signal across this space is called a neurotransmitter
Explanation:
A synapse is the junction between dendrites of two adjacent neurons. Its function is to allow the transmission of nerve impulses from neurone to neurone. Tn the presynaptic knob there are vesicles which contain a transmitter substance which is usually acetylcholine. The acetylcholine diffuses from the presynaptic membrane to the postsynaptic membrane.
