Regulation  control and coordination of life functions and activities  2 systems involved: 1. nervous- electrical system, brain,spine and nerves found in multicellular organisms 2. endocrine- chemical system, hormones found in all organisms Nervous System: definitions: a. stimulus- “message”; electrochemical charge sent along a nerve cell (neuron) change in the internal or external environment that triggers an impulse which ends in a response b. impulse-

c. receptor-structures that detect stimuli ex) sense organs d. response- reaction to a stimulus carried out by the effectors e. effector-organs of response include muscles & glands Parts of a neuron: f. neuron-nerve cell, functional unit of nervous system a bundle of neurons is a nerve fibers that detect stimuli generate impulse toward cyton 2. cyton-“cell body” contains nucleus fibers that send impulse away from cyton to terminal branches 3. axon- 1. dendrites-

4. terminal branches-  end of axon Direction of impulse: cyton nucleus dendrites node of Ranvier axon nucleus/Schwann cell myelin Schwann cell (produces myelin) terminal branches synaptic knobs  contain synaptic knobs that secrete neurotransmitters

definitions cont’d g. synapse-space between 2 neurons or between neuron & effector neurons are not connected h. neurotransmitters-chemicals that aid in the transmission of impulses across a synapse ex) acetylcholine

Path of an impulse to brain/spinal cord: stimulus (dendrites of sensory neuron) synapse cytonaxon dendrites of next neuron …….until it reaches brain or spinal cord End of notes for neuron quiz terminal branch

Types of Neurons : relay impulse from receptor to brain or spinal cord in the CNS (Central Nervous System) found in sense organs “neurons of motion” relay impulse from CNS to effectors b. motor- a. sensory- impulse relay causes muscle to contract or gland to secrete hormones “relays” in brain & spinal cord interpret & relay impulse between sensory & motor neurons c. inter-

Reflex An involuntary, automatic response to a stimulus Impulse does NOT travel to the brain stimulus interneuron (spinal cord) motor neuron (effector) RESPONSE sensory neuron (receptor)

See Awesome Adaptations sheet Functional Organization: Human Nervous System brain, spinal cord, interneurons Central Nervous System (CNS) Peripheral Nervous System (PNS) nerves outside of the CNS; sensory and motor neurons

A. Central Nervous System 1.Brain  100 billion neurons  3 lb. organ, uses 20% of body’s oxygen  protected by skull, meninges (tough membrane) and cerebrospinal fluid (CSF)  Composed of 2 sides called hemispheres the 2 hemispheres communicate via the nerves of the corpus callossum largest part a. cerebrum right hemisphere controls the left side of the body & vice-versa  3 major parts: is convoluted (folded) to increase surface area for information storage

functions: located beneath the rear of cerebrum b. cerebellum- coordinates motor activities, maintains balance 2. voluntary motor activity (movement) is initiated 3. responsible for thinking, learning & memory affected by alcohol and if damaged can cause loss of balance or tremors 1. sensory impulses are interpreted c. medulla oblongata- (brainstem) controls involuntary actions (heart, digestion, breathing) connects brain & spinal cord

hypothalamus spinal cord medulla cerebellum corpus callosum cerebrum thalamus

Other brain terms: gray matter- hypothalamus- any region in the brain or spinal cord that contains cytons white matter- thalamus- contains myelin & axons relay area/center btwn. brain & spinal cord controls body temp, blood pressure, sleep & emotions acts like a gland by stimulating pituitary connected to pituitary gland

1.Spinal Cord-  thick nerves protected by vertebrae (backbones)  all nerves outside of CNS  continuous w/medulla  controls reflexes  connects brain to PNS  covered by meninges  surrounded by CSF B. Peripheral Nervous System  those connected to brain are cranial nerves 12 pairs servicing head & sense organs  those connected to spinal cord are spinal nerves 31 pairs throughout the body

2 Divisions of the PNS somatic-nerves that control both voluntary movement (motor neurons) and sense organs (sensory neurons) autonomic-nerves that control involuntary actions like breathing & heart rate. Made of 2 subdivisions: 1. sympathetic 2. parasympathetic antagonists; have opposite effects

Sympathetic Parasympathetic Neurotransmitter effects on: heart vessels eyes norepinepherine (excitatory) prepares for emergency speeds up constricts (gets small) pupils dilate acetylcholine (inhibitory) returns body to normal, relaxed state slows down dilate (get big) pupils constrict

Malfunctions of the Nervous System: A. Cerebral Palsy- disease that affects cerebrum and creates problems w/motor functions, voluntary action and memory results from a hemorrhage (excessive bleeding due to broken blood vessel) or a blood clot in the cerebrum C. Stroke- viral disease of the CNS inflammation of the membranes surrounding the brain & spinal cord D. Polio- B. Meningitis- may result in paralysis is preventable by immunization

Nervous System CentralPeripheral brain spinal cord somaticautonomic sympatheticparasympathetic End of info for human n. sys quiz