If a person receives a blow on the back, then it will lead in an impairment of cognitive abilities or physical functioning. It can also result in the disturbance of behavioural or emotional functioning. Cervical injuries often lead to quadriplegia (tetraplegia).

The eustachian tube connects the middle ear cavity with the pharynx. It helps in equalising the pressures on either sides of the ear drum. At the pharyngeal opening of the Eustachian tube, is a valve which normally remains closed. The valve opens during yawning, swallowing and during an abrupt change in altitude, when air enters or leaves the tympanic cavity to equalise the pressure of air on the two sides of the tympanic membrane.

Representation of the following parts of eye

A neuron has three main parts

(i) Cell body (ii) Axon (iii) Dendrites

Any stimulus/nerve impulse passes from one neuron to another via axon. This nerve impulse is wave of bioelectric/electrochemical disturbance that passes along neuron during conduction of an excitation.

Transport and release of a neurotransmitter occurs within a synapse. At a chemical synapse, the membranes of the pre- and post-synaptic neurons are separated by a fluid-filled space called synaptic cleft. Chemicals called neurotransmitters are involved in the transmission of impulses at these synapses. The axon terminals contain vesicles filled with these neurotransmitters. When an impulse (action potential) arrives at the axon terminal, it stimulates the movement of the synaptic vesicles towards the membrane, where they fuse with the plasma membrane and release their neurotransmitters in the synaptic cleft. The released neurotransmitters bind to their specific receptors, present on the post-synaptic membrane. This binding opens ion channels allowing the entry of ions which can generate a new action potential in the post-synaptic neuron.

The forebrain is the largest part of the brain most of which is cerebrum. Other important structures include the thalamus, hypothalamus and the limbic system. The cerebrum is divided into two cerebral hemisphere connected here by a mass of white matter known is corpus callosum. Each hemispere is split into four lobes. The surface of each hemisphere is made up of grey matter known as the cerebral cortex that is folded to increase the surface area. Various structures of forebrain are given below

Brain Region	Structure	Function
Diencephalon	Thalamus	Organising sensory information
Diencephalon	Hypothalamus	Endocrine system, thermoregulation
Diencephalon	Pituitary	Endocrine system
Telencephalon	Cerebral cortex	Consciousness, language, etc
Telencephalon	Limbic system	Memory, motivation, emotions
Telencephalon	Olfactory bulb / lobes	Smell

Thalamus

The thalamus has many functions including processing and relaying sensory information selectively to various parts of the cerebral cortex, translating signals to the cerebral cortex and also regulating states of sleep and wakefulness. The thalamus plays a major role in regulating arousal levels of consciousness and levels of activity.

Hypothalamus

The function of the hypothalamus is mainly related to the overall regulation of the endocrine system and closely related to the pituitary gland.

Pituitary

The function of the pituitary is mainly related to the production of hormones as part of the endocrine system.

Cerebral Cortex

The cerebral cortex is essential for memory, attention, awareness, thought, language and consciousness. The cerebral cortex is connected to structures such as the thalamus and the basal ganglia, sending information to them along efferent connections and receiving information form them via afferent connections.

Motor Cortex

The motor cortex areas of the brain are located in both hemispheres of the cortex are related to controlling voluntary movements, especially fine movements.

Sensory Areas

The sensory areas are the areas theat receive and process information from the senses. inputs form the thalamus are called primary sensory areas, where vision, hearing and touch are processed. The two hemispheres of the cerebral cortex receive information form the opposite (contra lateral) side of the body.

The association areas of the brain function to produce a perception of the world enabling an animal to interact with their environment effectively. The frontal lobe or prefrontal association complex is involved in planning actions and movement.

Limbic System

The limbic system is principally responsible for emotions and the various types of emotion can affect the activity of the Autonomic Nervous System (ANS) facilitated by the hypothalamus.

Olfactory Bulb

The olfactory bulb is responsible for olfaction concerned with sense of small plays.