1. Sensory and Motor Mechanisms www.msbabbey.wikispaces.com

2.  Being able to detect and respond to the environment is important for survival.  Systems involved include: nervous, skeletal, and muscle www.msbabbey.wikispaces.com

3.  1. Sensory reception: detection of a stimulus by sensory cells (neurons, skin, ears, eyes, etc)  2. Transmission: an action potential is sent to the CNS  3. Perception: the brain processes the input into understandable images  4. Amplification and Adaptation: signals are increased or decreased based on importance www.msbabbey.wikispaces.com

4.  1. Mechanoreceptors: sense physical changes caused by pressure, touch, stretch, motion, and sound. Often have hairs attached externally.  2. Chemoreceptors: detect changes in solute such as glucose, oxygen, carbon dioxide, amino acids. Can be internal (blood) or external (antennae) www.msbabbey.wikispaces.com

5.  3. Electromagnetic receptors: detect light, electricity, and magnetism. Found in eyes, skull.  4. Thermoreceptors: detect heat and cold. Located in the skin.  5. Pain receptors: neurons that detect thermal, mechanical, or chemical stimuli www.msbabbey.wikispaces.com

6.  Hearing: ears have tiny hairs that vibrate due to pressure waves and send signals to the brain  Equilibrium: These same hairs help orient your body, telling your brain the position of your head. www.msbabbey.wikispaces.com

7.  Gustation (taste) and olfaction (smell) depend on chemoreceptors in the nose and mouth. www.msbabbey.wikispaces.com

8.  Invertebrates have photoreceptors, which detect light.  Insects have compound eyes, made up to several thousand light detectors  Our eyes have photoreceptors called rods and cones that send information through the optical nerve to the brain. www.msbabbey.wikispaces.com

9.  Smooth muscle: evolved first, non-striated, involuntary, digestive system, arteries, veins  Cardiac muscle: striated, in the heart, involuntary  Skeletal muscle: striated, multi-nucleated, voluntary, moves your body  Muscles are connected to the 206 bones in the body www.msbabbey.wikispaces.com

10.  Muscles do work in pairs, one contracts and one extends ◦ Tendons connect bone to muscle ◦ Ligaments connect bone to bone www.msbabbey.wikispaces.com

11.  Muscle cells are called muscle fibers, and are divided into sections called sarcomeres ◦ Made of bands of protein: thin (actin) & thick (myosin) www.msbabbey.wikispaces.com

12.  Sarcoplasm ◦ muscle cell cytoplasm ◦ contains many mitochondria  Sarcoplasmic reticulum (SR) ◦ organelle similar to ER, it stores and releases Ca 2+ as needed Ca 2+ ATPase of SR www.msbabbey.wikispaces.com

13.  Muscle movement is activated by the release of the neurotransmitter acetylcholine www.msbabbey.wikispaces.com

14.  Nerve signal travels to muscles  Muscles release Ca 2+  This causes muscles to contract www.msbabbey.wikispaces.com

15.  Slow twitch muscle fibers ◦ contract slowly, but keep going for a long time ◦ long distance runner ◦ “dark” meat = more blood vessels  Fast twitch muscle fibers ◦ contract quickly, but get tired rapidly ◦ sprinter ◦ “white” meat www.msbabbey.wikispaces.com

16.  Muscle fatigue ◦ lack of sugar  lack of ATP to restore Ca 2+ gradient ◦ low O 2  lactic acid drops pH which interferes with protein function ◦ synaptic fatigue  loss of acetylcholine  Muscle cramps ◦ build up of lactic acid ◦ ATP depletion ◦ ion imbalance  massage or stretching increases circulation www.msbabbey.wikispaces.com

17.  Some animals have exoskeletons made of chitin (arthropods and mollusks)  Internal skeletons are called endoskeletons. www.msbabbey.wikispaces.com

18.  Muscles, skeletons, and the nervous system work together to produce movement, or locomotion, like:  Swimming (with flagella or a whole organism)  Walking, running, hopping, crawling, maintaining balance  Flying www.msbabbey.wikispaces.com