At the leading edge of the impulse, the sodium gates open. The membrane becomes more permeable to Na + ions and an action potential occurs. As the action potential passes, potassium gates open, allowing K + ions to flow out. The action potential continues to move along the axon in the direction of the nerve impulse. At rest. Action Potential Section 35-2 Figure 35-7 An Impulse Action Potential Nerve Impulse
Vesicle Axon Axon terminal Synaptic cleft Neurotransmitter Receptor Dendrite of adjacent neuron Direction of Impulse Section 35-2 Figure 35-8 The Synapse The Synapse When an impulse reaches the end of one neuron, neurotransmitters are released into the synaptic cleft
Neurons in the brain also communicate with chemicals Serotonin, Histamine, Dopamine, Norepinephrine and Epinephrine
Pons Pituitary gland Hypothalamus Cerebrum Medulla oblongata Spinal cord Cerebellum Pineal gland Thalamus Figure 35-9 The Brain Central Nervous System – Brain and Spinal Cord
Interneuron (relay neuron): Relays message from sensory neuron to motor neuron Make up the brain and spinal cord
Spinal nerve Central canalGray matter White matter Meninges Section 35-3 Figure 35-11 The Spinal Cord Spinal Cord
Autonomic Nervous System Controls the functions of the body that are not under conscious control
PET SCAN or MRI As you read this passage quietly to yourself, certain parts of your brain are working to try to make sense of different aspects of the information contained in this text. We can actually take a picture of the activity in the brain as its owner engages in certain behaviors and the picture tells us what parts of the brain are most active during that behavior. The outer surface of the brain (called the Neocortex) is functionally divided into four lobes - the frontal lobe at the front of the head, the occipital lobe at the back of the head, the temporal lobe on the side, and the parietal lobe on the top.
Brain Activity With a PET scan, radioactive glucose is injected into the blood stream. The most active neurons absorb more of the radioactive glucose, so it is easy to take a picture of the brain's activity during different tasks.
Cerebrum Frontal Lobe- associated with reasoning, planning, parts of speech, movement, emotions, and problem solving Parietal Lobe- associated with movement, orientation, recognition, perception of stimuli Occipital Lobe- associated with visual processing Temporal Lobe- associated with perception and recognition of auditory stimuli, memory, and speech
Cerebellum The cerebellum, or "little brain", is similar to the cerebrum in that it has two hemispheres and has a highly folded surface or cortex. This structure is associated with regulation and coordination of movement, posture, and balance
Limbic System: The limbic system, often referred to as the "emotional brain", is found buried within the cerebrum. Thalamus Hypothalamus Amygdala Hippocampus Brain Structures and Their FunctionsBrain Structures and Their Functions
Brain Stem This structure is responsible for basic vital life functions such as breathing, heartbeat, and blood pressure. Midbrain Pons Medulla Brain Structures and Their FunctionsBrain Structures and Their Functions
Respiratory SystemDigestive SystemExcretory System Endocrine System Reproductive System Lymphatic System Section 35-1 Figure 35-2 Human Organ Systems Part 2 In what ways does the nervous system interact with the other systems below ?