Exam #3 W 4/2 in class Review T 4/1 from 5-7pm in PAI 3.02 Before Exam #3: the nervous system, movement and the immune system

CB 48.3 Nerves allow us to perceive the environment while the brain integrates the incoming signals to determine an appropriate response. Response

CB 48.5 Neurons: signals move through neurons electrically and between neurons chemically

electrical at synapse chemical At the synapse the electrical signal is converted to a chemical signal

CB Neurons are commonly connected to many other neurons, and the effect of the different incoming signals determines what the neuron will do.

Incoming signals move through neurons. Only signals above the threshold are transmitted along the neuron.

CB 49.3 Sensory neurons in human skin

Nervous System Signaling Stimulus Transduction Transmission Response Integration

Smells are detected by receptor neurons in our nose. Each receptor is sensitive to a different chemical CB 49.15

CB The brain and the central nervous system integrate the various incoming signals

CB Human Brain Development: Cerebrum- integration and memory Brainstem- homeostasis and input sensory info Cerebellum- motor functions Diencephalon- input to cerebrum and homeostasis

CB Cerebrum: higher brain function

CB Neocortex: thin layer on outside of the cerebrum. Highly convoluted in humans, ~5mm thick but ~80% brain mass.

CB Corpus Callosum: communication between hemispheres

CB Different regions of the cerebral cortex integrate different inputs/outputs

CB Visualizing the specialization of brain regions

CB Some body parts have more sensory input/ motor control Sensory input motor output

CB 48.3 Nerves allow us to perceive the environment while the brain integrates the incoming signals to determine an appropriate response. Response Responses can be release of hormones, change in cell activity, or muscle contraction

Muscles allow movement

An earthworm: without something to push against, muscles are not much use. CB 49.25

The skeleton, made of bones, gives support CB 49.26

Bones (connective tissue) are alive

Connections between bones and muscles

CB Muscles can only contract. Therefore, two muscles are needed for each range of motion.

2 nerve signals for every movement: excitatory and inhibitory CB 49.27

How do muscles contract?

CB Excitatory neuro- transmitters released by motor neurons cause muscle cells to contract

Muscle cells are comprised of series of sarcomeres. CB 49.28

Each sarcomere is a repeating unit of actin and myosin proteins CB 49.28

As each sarcomere contracts, the muscle contracts CB 49.28

CB Neuro- transmitters released at nerve/ muscle junction cause calcium to be released in muscle

CB A third protein, tropomyosin controls when the muscle contracts

CB ATP provides the energy for myosin movement along the actin

CB and.33 The contraction of muscle cells causes the muscle to contract

CB 48.3 Nerves allow us to perceive the environment while the brain integrates the incoming signals to determine an appropriate response. Response Responses can be release of hormones, change in cell activity, or muscle contraction

How do muscles contract?

Einstein’s Brain:

A video about different human reactions to cool:

Exam #3 W 4/2 in class Review T 4/1 from 5-7pm in PAI 3.02 Before Exam #3: the nervous system, movement and the immune system