The Brain Principles of Health Science

Name the main divisions of the Nervous System Identify the four main parts of the Neuron Investigate the parts and functions of the Brain Define, pronounce, and spell key terms of the Nervous System

The nervous system is the most highly organized system in the human body. It coordinates all the activities of the body. Responds and adapts to changes both inside and outside the body. It is a fast, complex communication system that regulates thoughts, emotions, movement, impressions, reasoning, learning, memory and choices. So how does the Nervous System work?

There are cells in the nervous system called Neurons or “nerve cells”. Neurons make up the communication of the brain. Neurons communicate with each other. About 100 billion neurons in human brain.

1.Cell body-(or soma) is the “receiving” surface of the neuron. 2.Dendrites-are multiple branches that come off the soma. The branches receive nerve impulses from other neurons. 3.Axon-is a single fiber that is thicker and longer than dendrites. The axon transmits neural messages from cell body away to another neuron at the synapse by neurotransmitters. 4.Myelin sheath-the lipid cover that insulates the axon. The more heavily insulated, the faster the electrical impulse to other neurons. There are about 10,000 synaptic contacts with other neurons.

1. The Central Nervous System (CNS) Consists of the brain and spinal cord. Serves as control center for entire organism. Takes incoming information and determines appropriate responses. 2. The Peripheral Nervous System (PNS) Made up of cranial and spinal nerves outside the CNS. Acts as communication lines to and from CNS Made up of sense organs—eyes, ears, taste buds, hearing, and touch receptors. There is also a separate division of the PNS called the Autonomic Nervous System that controls involuntary body functions.

Part of the PNS that controls involuntary functions and allows the body to react in times of emergency by two divisions: Sympathetic NS- in times of emergency, the SNS prepares the body to act by increasing heart rate, respirations, and blood pressure, and also slows the digestive tract. This is know as FIGHT OR FLIGHT RESPONSE! Parasympathetic NS-after the emergency the PNS stabilizes by slowing the heart rate, respirations, blood pressure and increasing the activity of the digestive tract.

The brain is a mass of nerve tissue protected by the cranium and other membranes. The 4 main sections of the brain are: Cerebrum, Cerebellum, Diencephalon, and the Brainstem (which consists of the Midbrain, Pons and the Medulla Oblongata). The structure of the brain is also divided by a right and a left hemisphere. Each side is organized to receive sensory information & control muscles from the opposite side of body. These hemispheres are connected by two bundles of axons known as the corpus callosum.

The largest and the most anterior part of the brain. The folds in the brain are called convolutions and are separated into lobes. The lobes include the frontal, parietal, temporal, and occipital lobes. The cerebrum is responsible for reasoning, thought, memory, speech, sensation, sight, smell, hearing, and voluntary movement.

1. Frontal Lobe- controls skeletal muscles, Broca’s speech (formation of sentences), and personality. Damage to frontal lobe can cause changes in personality 2. Temporal Lobe- controls hearing, smelling, understanding language and speech production. Damage can result in aphasia (partial or total inability to produce and understand speech). 3. Parietal Lobe- controls sensory association areas. Impulses of the skin such as pain, heat, touch, and temperature are interpreted. Also regulates estimation of distances, sizes, and shapes 4. Occipital Lobe- controls vision. Trauma can result in blindness and tumors can cause visual hallucinations.

Located in the back of the Cerebrum (hindbrain). Responsible for muscle coordination, balance (equilibrium), posture, and muscle tone.

Located between the Cerebrum and the midbrain and contains 4 structures: 1. Thalamus-acts as a relay station for all sensory impulses (except smell) and directs them to the cerebrum. 2. Pineal Gland-a small gland posterior to thalamus. It secretes the hormone melatonin that regulates sleep/wake cycles.

3. Hypothalamus-helps maintain homeostasis; body temperature, appetite, water balance and sleep. It also regulates emotions such as fear, anger, pleasure, pain, and affection. 4. Pituitary Gland-is attached to the hypothalamus. Also called “master gland” and sometimes called “The Boss” because it secretes hormones to tell other glands when and what to do such as the thyroid, adrenal glands, growth, puberty, ovaries and testes.

The midbrain-located below the cerebrum and is responsible for impulses between brain parts and for certain eye and hearing reflexes. Pons-located below the midbrain; sends messages to other parts of the brain for certain reflexes such as chewing, tasting, saliva production, and assists with respiration. Medulla Oblongata-posterior part of the brainstem and connects with the spinal cord. Controls heartbeat, respiration and blood pressure. Also controls reflexes such as swallowing, coughing, sneezing and vomiting!

Continues down form the Medulla Oblongata and ends at the 1 st or 2 nd lumbar vertebrae. It is protected by the vertebra. It is responsible for the reflex activities of the body. Transmits information back and forth from cranial and spinal nerves of Peripheral NS to brain. Afferent-messages sent to the brain. Efferent-messages from the brain. The Cerebrospinal Fluid-carries nutrients and serves as a shock absorber to protect the brain and the spinal cord.

Cerebral Palsy Cerebral Vascular Attack (CVA) Encephalitis Epilepsy Hydrocephalus Meningitis Multiple Sclerosis Paralysis-Para and Quadriplegia Parkinson’s Disease Shingles