BIOLOGY [Nervous System]

• The cerebral cortex is the outer layer of gray matter that covers most of the brain's surface.
• The cerebellum, located at the back of the skull, controls balance and coordination.
• The medulla oblongata, located near the base of the brainstem, regulates vital functions such as breathing and heart rate.
• The nervous system transmits signals between the brain and the rest of the body, including internal organs. 
• The basic unit of the nervous system is a nerve cell or neuron.
• Central Nervous System (CNS) - is made up of the brain and spinal cord. It serves as the main processing center for the entire nervous system. 
• Peripheral Nervous System (PNS) - is made up of the somatic and autonomic nervous systems. Its primary role is to relay information between our brain and the rest of the body. 
• Brain - weighs between 1.3 to 1.4 kg, with about 60% of the brain consisting of fat.
• The remaining 40% of the brain consists of protein, water, carbohydrates, and salts. 
• Brain - is an organ located within the skull that functions as an organizer and distributor of information for the body.
• The brain has its three main parts, namely: cerebellum, cerebrum, and brainstem
• Autonomic Nervous System - regulates involuntary actions like heart rate, breathing, digestion, blood pressure, and glandular secretions.
• Somatic Nervous System - controls voluntary movements such as walking, talking, writing, etc. This part of the PNS also receives sensory input from receptors throughout the body.
• Cerebellum - is responsible for coordinating voluntary movements such as walking, running, jumping, etc.
• Cerebrum - is divided into two hemispheres, left and right, which are connected by a bundle of nerve fibers called corpus callosum. The cerebrum controls higher mental processes like thinking, reasoning, learning, memory, speech, emotions, and personality.
• Brainstem - connects the brain to the spinal cord. It regulates vital life-supporting activities such as breathing, heartbeat, blood pressure, digestion, sleep, and wakefulness.
• Somatic Nervous System - controls voluntary movements such as walking or grasping objects.
• Hindbrain – includes the pons, medulla oblongata, cerebellum, and vestibular apparatus.
• Cerebrum - the most significant part of the brain.
• Cerebrum, is divided into the right and left cerebral hemispheres, both connected by the corpus callosum. 
• The cerebrum is responsible for regulating voluntary motor function, coordination, and balance. 
• Forebrain - consists of the thalamus, hypothalamus, limbic system, and basal ganglia. It plays a role in regulating consciousness, emotion, motivation, and behavior.
• Midbrain - located between the hindbrain and forebrain. It receives sensory information from the eyes and ears and sends motor commands to muscles involved in eye movement and balance.
• The cerebrum has four lobes: frontal lobe, parietal lobe, temporal lobe, occipital lobe.
• The spinal cord is a long tube-like structure that extends from the brain.
• spinal cord has a total of 31 pairs of nerves and nerve roots.  
• spinal cord serves as a channel for signals between the brain and the rest of the body and controls simple musculoskeletal reflex without input from the brain
• spinal cord is the longest nerve in the body, it connects the brain to the rest of the body
• somatic nervous system primarily sense the external environment and controls voluntary activities.  
• Spinal nerves connect the spinal cord with other parts of the body.
• The brain communicates with most of the body through the spinal nerves.
• Cranial nerve is a nerve fiber that carries information into and out of the brain stem.  
• Cranial nerves transmit sensory information, including touch, vision, taste, smell, and hearing. 
• autonomic nervous system primarily senses the internal environment
• Autonomic Nervous System (ANS) regulates involuntary actions such as heart rate, breathing, digestion, blood pressure, and sweating.
• Sympathetic division prepares the body for action by increasing heart rate, dilating pupils, constricting airways, and releasing adrenaline from the adrenal medulla.
• Parasympathetic division slows down the heart rate, relaxes muscles, increases saliva production, and stimulates digestive enzyme secretions.
• Sympathetic Division speeds up processes like heartbeat and digestion during times of stress or danger.
• Parasympathetic division slows down processes like heartbeat and digestion when they are not needed.