Plastic Movie: M 4/13 at 7pm in Welch Today: Intro to Animals and the Nervous System

Fig 1.9 Life as we know it… the animals

Protostomes Deuterostomes Fig 32.8 Animal Development

One important consideration of structure and function…surface area Nalca leaves

One important consideration of structure and function…surface area See fig's

Why is surface area so critical? Animals (and plants) must exchange various components with the environment

Organisms are organized: atoms molecules organelles cells tissues organs systems organisms Fig 41.8

Four major tissue types in animals: epithelial, connective, muscle, and nervous Fig 41.8

Fig 41.6 Epithelieal tissue: Covers and lines body and/or parts. Tightly packed cells.

Connective tissue: Holds and supports. Few cells with an extensive extracellular matrix. Fig 41.3

Fig 41.5 Muscle tissue: Movement. Long muscle fibers cells. Nerve tissue: Signaling. Generally long cells, neurons. Fig 41.4

Different tissues that comprise the stomach, an organ.

Homeostasis: Maintaining a steady-state internal condition Fig 41.14

Sensing and reacting to the environment is critical

Failure to properly sense and react to the environment can be fatal

Fig Nerves allow us to perceive the environment while the brain integrates the incoming signals to determine an appropriate response.

Fig 45.3 Neurons: cells specialized for transmitting signals

Axon Parts of a neuron Signals Fig 45.3

In the brain neurons are shorter and highly interconnected

Neurons: signals move through neurons electrically and between neurons chemically

Nervous System Signaling Stimulus Transduction Response

Na + /K + pump plasma membrane Na + K+K+ ATP–>ADP Fig 45.4 Ionic gradients in neurons

Fig At rest, the Na + /K + gradient is maintained

Depolarization occurs with the opening of Na + channels Fig 45.11

An action potential starts when the local depolarization causes other Na + channels to open Fig 45.11

Action potentials only occur when the initial depolarization is above the threshold

Fig An action potential starts when the local depolarization causes other Na + channels to open

Fig 45.6 Repolarization is achieved via closing Na + and opening K + channels

Fig the Na + /K + pump reestablishes the resting state

Depolarization of one part of the membrane opens Na + channels further along so the signal travels from one end to the other Fig 45.11

Neurons: signals move through neurons electrically and between neurons chemically

Plastic Movie: M 4/13 at 7pm in Welch Coming up: Nervous system and Immune system