Chapter 21: Neural Control and Coordination

Any nerve impulse is passed from one neuron to another neuron via the axon. Transport and release of a neurotransmitter occur within a synapse. At a chemical synapse, the membranes of the pre- and post-synaptic neurons are separated by a fluid-filled space called the synaptic cleft. At these synapses, chemicals called transmitters are involved in the transmission of impulses.

Cerebrum – It is further divided into 4 lobes:

a. Frontal lobe – associated with parts of speech, reasoning, planning, problem-solving and movement.

b. Parietal lobe – Helps in movement, perception of stimuli and orientation.

c. Occipital lobe – Visual processing

d. Temporal lobe – memory and speech.

Thalamus- It is a small structure located right above the brain stem. It helps in the sensory information from the sense organs. It is found in the limbic system within the cerebrum.

Hypothalamus – The hypothalamus is a small and important part of the brain, located exactly below the thalamus. It controls the mood and emotions and synthesis body’s essential hormones.

The middle ear contains three ossicles which are arranged in a chain fashion called the malleus, incus and stapes

The malleus is attached to the tympanic membrane and the stapes is attached to the oval window of the cochlea. A Eustachian tube connects the middle ear cavity with the pharynx and helps in equalizing the pressures on either side of the eardrum.

The inner ear is also called labyrinth, which is fluid-filled and has two parts, the bony and the membranous labyrinth. Former is the series of channels inside this membranous labyrinth that is present and surrounded by a fluid called perilymph. The membranous labyrinth is filled with a fluid called endolymph. The coiled portion of the labyrinth is called the cochlea. Endolymph is filled in scala media. At the base of the cochlea, the scala vestibule ends at the oval window, while the scala tympani terminates at the round window, which opens to the middle ear.