180 likes | 192 Views
Discover how the nervous system maintains homeostasis, its functions, neuron anatomy, types, divisions, brain parts, and interactions with other body systems.
E N D
3/5 • Get out Body Systems Booklet • Open to nervous system lab • Go back to your trials and continue your analysis questions
Nervous System-Regulation requires homeostasis –the ability of the body or a cell to seek and maintain stability within its internal environment when dealing with external changes. -The nervous system maintains homeostasis by controlling and regulating all other parts of the body. REGULATION
Functions of the Nervous System • Sensory-uses receptors to gather information from all over the body 2. Interpretation-the brain then processes the information into possible responses 3. Response-sends messages back through the system of nerve cells to control body parts
Evolutionary Trends of the Nervous System Complex Simple
Structures of the Nervous System Neurons: the functional cell that transmits signals through the body; an individual nerve cell Parts of a Neuron • cell body- the largest part of the neuron; contains the nucleus and organelles 2. dendrites- short, branching extensions spreading out from the cell body; receive and carry impulses to the cell body 3. axon- long, fibrous part of neuron; conducts nerve impulses away from cell body 4. at the end of the axon, the impulse travels across the synapse, a tiny gap separating the axon of one neuron from the dendrite of another
What is a nerve impulse? Nerve Impulse- an electrical signal is sent from the dendrite, along the axon, to the terminal. A chemical message, called a neurotransmitter is released from the axon terminals into the synapse, where it travels to the next cell.
Types of Neurons a. sensory neurons- carry messages from sense organs to brain b. motor neurons- carry impulses from the brain/spinal cord to muscles/organs c. interneurons- carry impulses between sensory and motor neurons
Divisions of the Nervous System • Central Nervous System (CNS) • Peripheral Nervous System (PNS)
Central Nervous System (CNS) • Brain- “control center”- receives and analyzes information; processes and sends back instructions
Parts of the Brain 1. Cerebrum controls thought, language, learning, judgment, & voluntary action 2. Cerebellum controls involuntary functions of muscles & maintains balance and posture 3. Brain stem Controls involuntary functions such as breathing, heart rate, and swallowing 4. Thalamus, Hypothalamus Controls homeostasis- temperature, hunger, thirst, fight or flight responses
Spinal cord- link between the brain and PNS; also controls reflexes Reflex: a simple, automatic response (ex. Hand on a tack)
Peripheral Nervous System (PNS) • Consists of nerves- ropelike bundles of neurons • Gathers information, delivers it to and from CNS
Levels of Organization Neurons Nerves Brain Nervous
Interaction with othersystems for Regulation • Bones of the skeletal systemprotect the spinal cord and brain. • The brain controls heart rate, blood pressure, and breathing via the circulatory and respiratory systems. • Glands in the brain control the release of hormones of the endocrine and reproductive systems. • The brain controls muscles both in digestion and movement.
Diseases / Disorders of the Nervous System • Polio- a virus that attacks the spinal cord; eventually causes paralysis • Multiple Sclerosis (MS)- affects neurons; slows nerve impulses, causing muscle weakness, possibly paralysis. • Alzheimer’s- brain tissue deteriorates; severe memory loss • Stroke- a blockage in a blood vessel in the brain, causing brain damage • Concussion- a bruise to the brain when the brain hits the inside of the skull
Fun Facts • A human body contains more nerve cells than there are stars in the Milky Way • Neurons are the largest cell in the body and do NOT undergo mitosis • Nerve impulses move at 100 meters per second or more • Longest axon of a neuron is 15 ft! (in the giraffe)
3/5 • Get out your nervous system notes packet • Pick up the “Touch Receptor Lab” • Get out a spare sheet of paper for your warm-up (1st & 2nd period only)
Warm-Up • Most athletes have impeccable coordination and balance. What part of the brain controls these functions? • After a serious car accident, a man suffers a traumatic head injury. The man is still breathing and his heart is functioning but he is in a coma. What part of his brain is still intact? • A student thinks it’s a good idea to jump off of a roof into a neighbor’s pool below…what part of his brain is responsible for his LACK of judgment and thought? • You are jogging at night and a large dog starts to chase you!! What part of your brain will release the hormone “adrenaline” to allow you to fight or escape the animal? • List in order the direction an electrical impulse travels down a neuron: