Communication Chapter 7: Signals from the eye and ear are transmitted as electro-chemical changes in the membranes of the optic and auditory nerves

The cerebrum perceives and interprets light and sound identify THE areas of the cerebrum involved in the perception and interpretation of light and sound THE CEREBRUM The brains of humans appear to be out of proportion compared with overall body size. This is due to the great enlargement of the cerebrum. The cerebrum splits into two hemispheres - a left and a right. Each hemisphere receives impulses from and exerts control over the opposite side of the body.

The cerebrum perceives and interprets light and sound identify THE areas of the cerebrum involved in the perception and interpretation of light and sound The hemispheres are divided into four lobes: Frontal Occipital Parietal Temporal Insular lobe- emotional experience

The cerebrum perceives and interprets light and sound identify THE areas of the cerebrum involved in the perception and interpretation of light and sound The tough protective covering of the brain is called the dura matter. The surface of the cerebrum is drawn up into folds called convolutions. This triples the surface area of the brain where important processes occur.

The cerebrum perceives and interprets light and sound identify THE areas of the cerebrum involved in the perception and interpretation of light and sound Most of the activities of the cerebrum occur on its outer surface, in a layer of grey matter (cerebral cortex) only a few millimetres thick. The greater the surface area of the cerebrum the greater the ability to perform functions.

The cerebrum perceives and interprets light and sound identify THE areas of the cerebrum involved in the perception and interpretation of light and sound Optic nerve LIGHT AND THE CEREBRUM Optic nerves are the sensory nerves of vision. Fibres arise from the retina of the eye to form the optic nerve. Each optic nerve passes through the skull via an opening in the eye socket. The optic nerves from each eye cross over partly to form the optic chiasma (cross).

The cerebrum perceives and interprets light and sound identify THE areas of the cerebrum involved in the perception and interpretation of light and sound About half of the nerves cross to the other side, providing each visual cortex with the same image as viewed by both eyes but each eye received the image at a slightly different angle.

The cerebrum perceives and interprets light and sound identify THE areas of the cerebrum involved in the perception and interpretation of light and sound A visual cortex lies within the occipital lobe of each cerebral hemisphere. Impulses reach this lobe from the retina via the optic nerve. Different sites on the visual cortex process information from different positions on the retina.

The cerebrum perceives and interprets light and sound identify THE areas of the cerebrum involved in the perception and interpretation of light and sound SOUND AND THE CEREBRUM Auditory nerves arise from the hearing (cochlea) and equilibrium (vestibule) within the inner ear. These merge to form the vestibulocochlear nerve. This nerve runs from the organ of Corti to the auditory cortex, in the temporal lobe of the brain.

The cerebrum perceives and interprets light and sound identify THE areas of the cerebrum involved in the perception and interpretation of light and sound An auditory cortex is found on the temporal lobe of each cerebral hemisphere. Different sites on this cortex receive and interpret different sound frequencies.

The mammalian brain perform a first-hand investigation to examine an appropriate mammalian brain or model of a human brain to gather information to distinguish the cerebrum, cerebellum and medulla oblongata and locate the regions involved in speech, sight and sound perception Page 87-90

Correct interpretation of signals explain, using specific examples, the importance of correct interpretation of sensory signals by the brain for the coordination of animal behaviour Stimuli must be received and transmitted to the brain or spinal cord before being interpreted and a response given. Some reasons that can cause a ‘short circuit’ include: Lack of stimulus Trauma Lack of oxygen Drug reaction Disease Age related damage or deterioration

Correct interpretation of signals explain, using specific examples, the importance of correct interpretation of sensory signals by the brain for the coordination of animal behaviour ALCOHOL, ANAESTHETICS AND SEDATIVES Can all impair the transmission of messages. They all block nerve impulses by reducing the plasma membrane’s permeability to sodium ions, resulting in no sodium entry into the neuron. As a result there is no action potential. Common symptoms include: poor coordination of movements, lack of concentration, retarded reflexes, tiredness, blurred vision and slurred speech.

Correct interpretation of signals explain, using specific examples, the importance of correct interpretation of sensory signals by the brain for the coordination of animal behaviour MULTIPLE SCLEROSIS Is a autoimmune disease in which there is an immune attack by the body on its own myelin protein. Gradually the myelin sheaths in the CNS are destroyed and become hard substances called scleroses. As the insulating layer becomes non-functional, the impulses are short circuited and finally conduction of the impulse ceases.

Correct interpretation of signals explain, using specific examples, the importance of correct interpretation of sensory signals by the brain for the coordination of animal behaviour Common symptoms include: problems controlling muscles (weakness, clumsiness, urinary incontinence) and visual disturbances (including blindness).

Correct interpretation of signals explain, using specific examples, the importance of correct interpretation of sensory signals by the brain for the coordination of animal behaviour CEREBRAL PALSY May be caused by a temporary lack of oxygen to a baby during a difficult delivery. It is a neuromuscular damage, in which the voluntary muscles lack coordination due to brain cell damage. The brain cells are unable to transmit a message to the muscles and as a result the muscles can not be controlled. Common symptoms include: impairments in movement, speech, hearing and vision.

Correct interpretation of signals explain, using specific examples, the importance of correct interpretation of sensory signals by the brain for the coordination of animal behaviour RUBELLA (German measles) Is caused by the rubella virus. The disease causes a fine rash, fever and sometimes, upper respiratory tract infection. If a woman contracts rubella in the first 3 months of pregnancy, the virus may pass through the placenta to the developing baby. Damage to the brain and spinal cord leads to a lack of transmission of nerve signals to various organs. The baby could then be affected by rubella congenital syndrome.

Correct interpretation of signals explain, using specific examples, the importance of correct interpretation of sensory signals by the brain for the coordination of animal behaviour Common symptoms include: cataracts, congenital glaucoma and retinopathy of the eye, loss of hearing, congenital heart disease, as well as problems with development of the brain, spinal cord, spleen, liver and possibly bones.

Correct interpretation of signals explain, using specific examples, the importance of correct interpretation of sensory signals by the brain for the coordination of animal behaviour AGE-RELATED DAMAGE OR DETERIORATION The human brain reaches its max size in young adulthood. From then on the neurones may be damaged and die, contributing to a gradual loss of weight and volume of the brain. The destruction of neurones is attributed to the build- up of calcium, which has a neurotoxic effect. Common symptoms include: decline in reaction time and speed of decision making, as well as memory loss.