Discussion Week 5

The Human Brain What are the different structures that make up the brain? Cerebrum Cerebral cortex, white matter, basal nuclei Diencephalon Thalamus, hypothalamus, epithalamus Midbrain Part of the brainstem Pons Also part of the brainstem, cerebellum Medulla oblongata ALSO part of the brainstem

Brain Organization Cerebrum Cerebellum Controls skeletal muscle Center for learning, emotion, memory, and perception Cerebral cortex – perception, voluntary movement, and learning Corpus callosum is necessary for the left and right cerebral hemispheres to communicate Movement and balance Learning and remembering motor skills Hand-eye coordination

Brain Organization Diencephalon Brainstem Thalamus – sensory information gets sorted and sent to the cerebrum Hypothalamus – body’s thermostat and central biological clock Pituitary gland - Hunger, thirst, sexual/mating behaviors, fight-or-flight response Epithalamus – pineal gland as source of melatonin Midbrain, pons, medulla Midbrain – Sensory information and visual reflexes Medulla – homeostatic functions: breathing, heart and blood vessel activity, swallowing, vomiting, and digestion Pons – helps regulate breathing centers in the medulla

Neurotransmitters Neurotransmitters allow communication between neurons and other cells Neurotransmitters travel across synapses between neurons and targets Acetylcholine tells muscles to contract

What happens if you block acetylcholine release?

What happens if you block inhibition of acetylcholine?

Action Potentials What is the threshold for this neuron? What does letter A represent? What does letter B represent? -50 mV Graded potential Inhibitory signals

Adding cholesterol, more saturated Cell Membranes Which cell membrane is more fluid? How could a cell decrease membrane fluidity? B Adding cholesterol, more saturated fatty acids

Osmosis Frog eggs are placed in solutions of different concentrations What concentrations are Hypertonic Isotonic Hypotonic > 0.4 M 0.4 M < 0.4 M

DNA Content The graph shows relative DNA content Match the samples to the following cells: Sperm Neuron Dividing endothelial cells 3 1 2