Science 10: The Nervous System PDF

SCIENCE 10 THE NERVE IMPULSE Teacher : Sophia Isabelle S. PLEASE, GIVE ME LABEL PLEASE, GIVE ME LABEL  DID YOU KNOW ? 1.The Human brain weights 3 pounds 2. It comprises 60% of fat and is one of the fattest organs in the human body 3. There are 100 billion...

SCIENCE 10 THE NERVE IMPULSE Teacher : Sophia Isabelle S. PLEASE, GIVE ME LABEL PLEASE, GIVE ME LABEL  DID YOU KNOW ? 1.The Human brain weights 3 pounds 2. It comprises 60% of fat and is one of the fattest organs in the human body 3. There are 100 billion neurons present in the brain 4. As we grow older, we are unable to remember new things. according to the researchers in the US it is because the brain is unable to filter and remove old memories which prevent it from absorbing new things What is Nervou s System The human body is made up of different systems that coordinate with one another to perform their functions well. If any of these organs fails, the body will lose its balance. The instability caused by the malfunctioning of one system cannot be made stable by other systems because each system has its own Your nervous system connects all your body parts and transmits signals from one part to another. It is a system of cells, tissues and organs that regulates the body’s responses to internal and external stimuli. Each part of the nervous system has a specific role as it functions as an important part of a MAJOR DIVISIONS AND PARTS OF THE NERVOUS SYSTEM 1. Central Nervous System (CNS ) 2. Peripheral Nervous System (PNS) 1. Central Nervous System (CNS) This is an organ located within the skull that functions as organizer and distributor of information for the body. It has three Main Parts: Cerebrum Cerebellum Brain Stem CEREBRUM The largest part of the brain, the cerebrum initiates and coordinates movement and regulates temperature. Other areas of the cerebrum enable speech, judgment, thinking and reasoning, problem- solving, emotions and learning. Other functions relate to vision, hearing,  CEREBELLUM The cerebellum (which is Latin for “little brain”) is a major structure of the hindbrain that is located near the brainstem. This part of the brain is responsible for coordinating voluntary movements. It is also responsible for a number of functions including motor skills such as balance, coordination, and posture. BRAIN STEM Your brainstem is the bottom, stalklike portion of your brain. It connects your brain to your spinal cord. The brainstem is a sort of automatic control center for several important involuntary actions of the body, such as heartbeat, breathing, blood pressure, and many reflexes. Sudden injuries, and brain or  SPINAL TheCORD spinal cord is a long, tube-like band of tissue. It connects your brain to your lower back. Your spinal cord carries nerve signals from your brain to your body and vice versa. These nerve signals help you feel sensations and move your body. Any damage to your spinal cord can affect your movement or function What does the spinal cord do? Motor Functions - directs your body's voluntary muscle movements. Sensory Functions – monitors sensation of touch, pressure, temperature and pain. Autonomic Functions – regulates digestion, urination, body temperature, heart rate, and dilation/contraction of 2. Peripheral Nervous System (PNS ) The peripheral nervous system consists of the nerves that branch out from the brain and spinal cord. These nerves form the communication network between the CNS and the body parts. The peripheral nervous system is further subdivided into the somatic nervous system and the autonomic nervous system. A.Somatic Nervous System this system is associated with the voluntary control of body movements and has two main a.1 Spinal parts. Nerves are nerves that carry motor and sensory signals between the spinal cord and a.2 the body.Nerves are Cranial the nerve fibers that carry information into and out of the brain stem. B. Automic Nervous System this system is associated with the involuntary control of body movements and has two (2) sub-divisions. b.1 Sympathetic – it is activated when the body is in a dynamic role or stress. (eg. Increased heart rate and breathing, dilation of pupil, sweating, etc) b.2 Parasympathetic - it maintains body functions and restores the body to normal or relaxed mode.  Nerve cell is the basic unit of the nervous system, nerve cells are called neurons. There are billions of neurons in the body. Some exist alone. Others are joined together to form organs like brain and spinal cord. In one part of the brain Neurons are alone there are specially 12-14 billion of neurons. NEURONS intended for information processing and signaling. They relay and receive messages (impulse) between the brain and the body, and within the brain and spinal cord. Motor Neurons transmit impulses from the brain to muscles, glands, or other neurons in the peripheral nervous system. Sensory neurons transmit impulses from sensory nerves (receptor) to the Central Nervous System (CNS). Nerve Neurons are cells with the special ability to carry signals or impulses. Thoughts, Impulse emotions, learning, and many body functions are carried by nerve impulses in the neurons. A nerve impulse is a combination of an electrical charge and chemical reaction. A nerve impulse is not a flow of electricity, but an electrochemical signal moving along a neuron. The Nerve Impulse cannot jump from one neuron to another. When a nerve impulse comes to an end of an axon, it produces the chemical, called NEUROTRANSMITTER to be released. The chemical crosses the space between neurons called SYNAPSE and stimulates the nerve impulse to start in the The Nervous System is assisted by fi ve (5) sense organs Eyes, Ears, Nose, Tongue, and Skin. These sense organs are constantly receiving information from the environment and sending messages to the brain. These senses aid in the survival of human beings. 1.Light hits the retina: Light enters the eye and hits the retina, a light-sensitive layer of tissue at the back of the eye. 2.Photoreceptors turn light into electrical signals: Special cells in the retina called photoreceptors convert the light into electrical signals. 3.Optic nerve carries signals to the brain: The electrical signals travel through the optic nerve to the brain. 4.Brain interprets signals as images: The brain decodes the signals and turns them into the images  STIMULUS refers to any factor in the environment that may trigger a nerve impulse. STIMULUS is received by the body and a RESPONSE is made. RESPONSE on the other hand is a reaction to a stimulus. Messages do not travel in both directions along the same neuron. Only the axon of the neuron releases STIMUL neurotransmitters that cross the space between neurons. Reaction Time is the length of US time between application of a stimulus and detection of a  LESSON 3: Human Disorders related to NervousSystem  Human Disorders 1. Neurodegenerative Disorders are both neurodegenerative disorders characterized by loss of nervous system functioning. a. Alzheimer’s disease is an irreversible, progressive brain disorder that slowly destroys memory and thinking skills and, eventually, the ability to carry out the simplest tasks. b. Parkinson’s disease is a brain disorder that leads to shaking, stiff ness, and diffi culty with walking, balance, and coordination. 2. Neurodevelopmental Disorders are neurodevelopmental disorders that arise when nervous system development is disrupted. a.Autism or autism spectrum disorder (ASD) refers to a broad range of conditions characterized by challenges with social skills, repetitive behaviors, speech, and nonverbal communication. b.Attention-deficit/hyperactivity disorder (ADHD) is one of the most common neurodevelopmental disorders of childhood. It is usually first diagnosed in childhood and often lasts into adulthood. Children with ADHD may have trouble paying attention, controlling impulsive behaviors (may act without thinking about what the result will be), or be overly active. 3. Neurodevelopmental Disorders: Mental Illnesses a. Schizophrenia a psychiatric diagnosis denoting a persistent, often chronic, mental illness variously aff ecting behavior, thinking, and emotion. b. Depression is caused by a decrease in norepinephrine and serotonin neurotransmission. 4. Other Neurological Disorders a. Epilepsy a medical condition in which the suff erer experiences seizures (or convulsions) and blackouts b. Stroke the loss of brain function arising when the blood supply to the brain is suddenly interrupted. 5. Gigantism is a serious condition that is nearly always caused by an adenoma, a tumor of the pituitary gland. Gigantism occurs in patients who had excessive growth hormone in childhood. The pituitary tumor cells secrete too much growth hormone (GH), leading to many changes in the body 6. Growth hormone defi ciency (GHD), also known as dwarfi sm or pituitary dwarfi sm, is a condition caused by insuffi cient amounts of growth hormone in the body.