● A `color{violet}("nerve impulse")` is `color{violet}("transmitted")` from one `color{violet}("neuron")` to another through junctions called `color{brown}("synapses.")`

● A `color{brown}("synapse")` is formed by the membranes of a `color{violet}("pre-synaptic neuron")` and a `color{violet}("post-synaptic neuron")`, which may or may not be separated by a gap called `color{brown}("synaptic cleft.")`

● There are two types of `color{violet}("synapses,")` namely, `color{brown}("electrical synapses")` and `color{brown}("chemical synapses.")`

● At `color{violet}("electrical synapses,")` the membranes of `color{violet}("pre- and post-synaptic")` neurons are in very `color{brown}("close proximity.")`

● `color{violet}("Electrical current")` can flow directly from one `color{violet}("neuron")` into the other across these `color{violet}("synapses.")`

● `color{violet}("Transmission of an impulse")` across `color{violet}("electrical synapses")` is very similar to impulse conduction along a `color{violet}("single axon.")`

● `color{violet}("Impulse transmission")` across an `color{violet}("electrical synapse")` is always `color{brown}("faster")` than that across a `color{violet}("chemical synapse.")`

● `color{violet}("Electrical synapses")` are rare in our system

● At a `color{brown}("chemical synapse,")` the membranes of the `color{violet}("pre- and post-synaptic")` neurons are separated by a fluid-filled space called `color{brown}("synaptic cleft.")`

● Chemicals called `color{brown}("neurotransmitters")` are involved in the transmission of impulses at these `color{violet}("synapses. ")`

● The `color{violet}("axon terminals")` contain `color{brown}("vesicles")` filled with these `color{violet}("neurotransmitters.")`

● When an `color{violet}("impulse")` (action potential) arrives at the `color{violet}("axon terminal")`, it stimulates the movement of the `color{violet}("synaptic vesicles")` towards the membrane where they fuse with the `color{violet}("plasma membrane")` and release their `color{violet}("neurotransmitters")` in the `color{violet}("synaptic cleft")`.

● The released `color{violet}("neurotransmitters bind")` to their specific `color{brown}("receptors,")` present on the `color{violet}("post-synaptic")` membrane.

● This binding opens `color{violet}("ion channels")` allowing the entry of `color{violet}("ions")` which can generate a new potential `color{brown}("in the post-synaptic neuron.")`

● The new potential developed may be either `color{brown}("excitatory or inhibitory")`

● The `color{violet}("brain")` is the `color{brown}("central information processing organ")` of our body, and acts as the `color{brown}("‘command and control system’.")`

● It controls the voluntary movements, balance of the body, functioning of `color{violet}("vital involuntary organs")` (e.g., lungs, heart, kidneys, etc.), thermoregulation, hunger and `color{violet}("thirst, circadian")` (24-hour) rhythms of our body, activities of several endocrine glands and human behaviour.

● It is also the site for processing of `color{violet}("vision, hearing, speech, memory, intelligence")`, emotions and thoughts.

● The `color{violet}("human brain")` is well protected by the `color{brown}("skull.")`

● Inside the skull, the brain is covered by `color{brown}("cranial meninges")` consisting of an outer layer called `color{brown}("dura mater,")` a very thin middle layer called `color{brown}("arachnoid")` and an inner layer (which is in contact with the `color{violet}("brain tissue")` ) called `color{brown}("pia mater.")`

● The `color{violet}("brain")` can be divided into three major parts: `color{brown}("(i) forebrain, (ii) midbrain,")` and `color{brown}("(iii) hindbrain ")`