WARM UP 11 4/28 Name the organ system. 1. Consists of the peripheral nerves, brain, and spinal cord 2. Function is to coordinate the body’s responses to changes in its internal and external environments 3. Consists of blood, blood vessels, and heart 4. Helps to protect the body from disease 5. Composed of hair, skin, nails, sweat, and oil grands 6. Controls growth, development, metabolism, and reproduction Put the following in smallest to largest: 7. Individual, cell, organ, tissue, organ system
The levels of organization in a multicellular organism from smallest to largest are: cell→ tissue → organ → organ system
Different tissue types work together within organs
What is the purpose of each of these items? Plastic Wrap Electrical Wire Packaging Tape
What type of tissue is represented by each item? Plastic Wrap Electrical Wire Packaging Tape epithelial nervous connective
Behind the scenes, your organ systems are working constantly to do something that few people appreciate- maintain a controlled, stable internal environment -cells must be kept at a certain temperature -supply energy through cellular respiration -clean waste products Failure at any of these tasks for a few minutes can lead to permanent injury or death
Nervous System Brain Spinal cord Peripheral nerves
Function: Controls & coordinates functions throughout the body Responds to internal & external stimuli Function:
Neurons- cells that transmit and carry messages (impulses) Dendrite Cell body Axon terminal Myelin sheath Nodes of Ranvier Axon Nucleus Structure of a Typical Neuron 100 billion neurons in the brain alone
3 types of neurons Classified by direction impulse travels 1) Sensory neurons- carries impulses from sense organs to spinal cord & brain 2) Motor neurons- brain/spinal cord to muscles 3) Interneurons- connect sensory & motor neurons
Nerve impulses are electrical Resting potential- neuron at rest (negative inside cell) Action potential- (positive inside cell) Threshold- minimum level of stimulus to activate neuron
Synapse Location neuron transfers an impulse to another cell Neurotransmitters- chemicals used by neuron to transmit an impulse to another cell Synapse
Page 897 vocab Axon Cell body Myelin sheath Nodes Dendrites Sketch picture Label parts Description for each part Page 897 Axon Myelin sheath Nodes Cell body Nucleus Dendrites vocab