Neurons – The building block STRUCTURENeuron: A single cell.Nerve: a bundle of neurons.Parts of neurons:1. Dendrites2. Axon3. Axon Terminal4. Cell body
Neurons – The building block FUNCTION Neurons vary greatly in size and shape. Neurons are classified into three categories ◦ Sensory neurons – transmit impulses from receptors to CNS ◦ Motor neurons – carry outgoing signals from CNS to muscles and glands ◦ Inter-neurons – connect sensory and motor neurons
Neurons – The building blockFUNCTION- Neural Communication Action Potentials ◦ Information travels along neuron in form of neural impulse called an action potential ◦ Each action potential is the result of movement of electrically charged particles (ions) in and out of neuron ◦ Movement of ions controlled by ion channels - when these are closed the neuron is referred to as “resting” ◦ When a neuron is depolarized above the excitation threshold cell membrane is temporarily unstable, resulting in action potential. Resting Potential: The state when neuron is charged but waiting for next action potential to be generated.
Neurons – The building blockFUNCTION- Neural Communication Action Potential
Neurons – The building blockFUNCTION- Neural Communication Importance of eating bananas!!
Neurons – The building block Synapse: tiny fluid filled gap between axon terminal and dendrites.
Neurons – The building blockFUNCTION Communication Between Neurons Synaptic transmission and neural coding ◦ All-or-none law – a neuron is either firing action potential, or not, so how can the nervous system code for/represent complexity of experience? ◦ Power of nervous system lies in the complexity of the connections between neurons ◦ Lock-and-key action – the way a neurotransmitter and receptor fit together, which causes a change in permeability of ion channels, either excitatory or inhibitory.
Neurons – The building blockNeurotransmitters ◦ More than 70 identified ◦ Acetylcholine – involved in memory and attention and transmits signals between nerve and muscle. ◦ Dopamine – mediates effects of natural rewards (e.g. food). Excess activity associated with schizophrenia. ◦ Serotonin – important role in mood regulation (SSRI). Also important in sleep and appetite
Neurons – The building blockNeurotransmitters Excitatory Effect: A neurotransmitter effect that makes it more likely that the receiving neuron will generate an action potential, or “fire.” Agonist: A drug that boosts the effect of a neurotransmitter. Inhibitory Effect: A neurotransmitter effect that makes it less likely that a receiving neuron will generate an action potential, or “fire.” Antagonist: A drug that blocks the effect of a neurotransmitter.
The Structure of Nervous System Nervous System Peripheral Central Autonomic Somatic Sypathetic Parasympathetic
THE BRAIN- Case Studies Psychologist and Doctors began to learn about brain functions by studying the changes in ability and personality caused by brain injuries. Case of Phineas Gage. The injury leading to his personality change. Whats another important information about function of the damaged area?
THE BRAIN- Scanning Structure: ◦ Computerized Axial Tomography (CAT)-X-rays. ◦ Magnetic Resonance Imaging (MRI)-magnetic fields and radio waves Function: ◦ Functional MRI ◦ Electroencephalogram (EEG)-electrodes ◦ Positron Emission Tomography (PET) – radioactive glucose
THE BRAIN- Parts The BrainSTEM- no visible or structural end. Spinal chord enters the brain and changes the shape into medulla and reticular formation. ◦ Medulla: Basic life support. ◦ Reticular formation: Nerve network involved in wakefulness and alertness.
THE BRAIN- Parts The Thalamus: Sits at the top of brainstem. “sensory Switchboard” All incoming sensory nerves go through thalamus and its function is to send them to correct cortical area. Cerebellum : (little brain) Its controls emotions, hearing, touch. Coordination of physical movements and balance.
THE BRAIN- Parts The Limbic System: a border in between brain stem and cerebral cortex. 3 parts of limbic system: ◦ Hypothalamus- hunger, thirst, fight or flight. ◦ Hippocampus- MEMORIES ◦ Amygdala- emotions.
THE BRAIN- CEREBRAL CORTEX 20-30 billion neurons can exist in a layer of brian tissue 1/8th inch thickness. Two kinds of Cells: ◦ Glial cells ◦ Neurons
THE BRAIN- CEREBRAL CORTEX Major division of cerebral cortex:1. Frontal Lobe2. Temporal Lobe3. Parietal Lobe4. Occipital Lobe
THE BRAIN- CEREBRAL CORTEX Movement: ◦ Motor Cortex Feelings ◦ Somatosensory cortex Plasticity: The ability of our brain to reprogram an a section for a new function.