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CRANEAL NERVE: There are 12 pairs of cranial nerves which enter and leaves the brain, including sensory,motor and mixed types.They innervate the head,the upper part of the torso and some of the body's internal organs, some are associated with the automatic nervous system, on their journey,we can see ganglia nerves,formed by groups of neuronal bodies. SPINAL NERVES: They come out the spinal cord, there are 31pairs of mixed nerves, each mixed root first emerges from the spinal cord as two distinct roots,which then join together to form a single nerve cord, all the sensory neurons enter the spinal cord through the dorsal root and all the motor neurons come out of the ventral root.THE AUTOMATIC NERVOUS SYSTEM: It regulates and controls involuntary body functions, the higher parts of the A.N.S are located in the grey matter of the spinal cord, in the spinal bulb and in the hypothalamus, nerves emerge from these areas and send signals to the organs. A.N.S is divided into: the sympathetic N.S and the parasympathetic N.S , each one develops opposite actions.PITUITARY GLANDS (posterior lobe): antidiuretic: This decrease the water excess in urine/Oxytocin: This contracts the muscle in the uterus during birth/(anterior lobe) stimulating hormones: activates the glands/growth hormone: promotes a lengthening of the bones and growth in general/THYROID GLAND: Thyrosine: stimulates metabolism/PARATHYROID GLANDS:Parathyroid hormone : regulates the amount of calcium and phosphorus in the blood/PANCREAS: insulin: stimulates the utilization of glucose by tissues and muscles/GLUCAGON: stimulates the conversion of glycogen to glucose/ ANDRENAL GLANDS: adrenaline: prepares the body to work, similar to the Sympathetic nervous system /corticosteroids: Regulate metabolic processes and the water in tissues/aldosterone: controls the concentration of sodium and potassium in the blood/OVARIES: estrogens: produce and maintain female sexual traits/progesterone: allows the embryo to be implanted in the uterus./TESTICLES: androgens: produce and maintain male sexual traits.SPINAL CORD: is a cord of nerve tissues that runs through the spinal canal, the grey matter is found in the centre, the white matter is found in the outer area of the S.C , there is a small channel in the grey matter, the ependyma (from top to bottom) contains cerebrospinal fliud, nerves start from the spinal cord and reach all the body except the head. S.C FUNCTIONS: It produces reflex actions, these actions happen due to responses to a stimulus, without the brain participating/ it carries sensory nerves towards the brain and motor nerve impulses from the brain to the effector organs, so the brain receives the information and sends it to an organ that can modify a reflex action.

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