Early Brain Development Chapter 9 Section 1 21

Early Brain Development Chapter 9 Section 1 21 st Century Families

Experience Matters

• Dendrites: Extensions from the neuron cell body that take information TO the cell body. • Nucleus: part of the neuron that contains chromosomes. (genetic material) • Cell Body: Also called the soma; the part of the cell that contains the nucleus. • Myelin: Fatty substance that surrounds some axons. Speeds up communication. • Node of Ranvier: Gaps in the myelination of axons. • Axon: The part of the neuron that takes information AWAY from the cell body. • Synaptic Terminal: The end of the axon containing vesicles with neurotransmitters. Also known as axon terminals. • Neurotransmitters: The chemicals released by an axon and cross the gap to the dendrite of another nerve cell. That gap is called a synapse.

What is going on here? Can you find the…. Axon Soma Dendrites Myelin Node of Ranvier Nucleus Synaptic Terminal

How Neurons Work § Step 1: § Dendrites receive information from other neurons. Each dendrite can have many different branches. § Step 2: § The dendrites pass that information to the body of the nerve cell, where the information is processed.

§ Step 3: § The nerve cell sends messages through axons, which transmits the messages to the dendrites. § The axons are coated with a waxy protein-based substance called myelin. § Myelin allows information to be transmitted more easily. § Step 4: § Chemical called neurotransmitters are released by the axon and cross the gap to the dendrite of another cell. § This gap is called the synapse.

Developing the Brain § More dendrites indicate increased learning. § An increased number of neural pathways results from sensory input. § Each child’s brain gets organized in a unique way, depending on his or her experiences. dendrite A branchlike feature at the end of each axon that receives the messages from other neurons. neural pathway The link between neurons.

Developing the Brain § Repetitive action causes the neurons to work together so that action becomes easier. § The brain can be reorganized. § Sensory activities increase neural pathways.

Developing the Brain § The brain continues to develop through responses to life’s experiences. § Caregivers can increase the speed of brain development with a stimulating environment. How can a stimulating environment encourage brain development?

Experience Can Change the Actual Structure of the Brain § Brain development is “activitydependent” § Every experience excites some neural circuits and leaves others alone § Neural circuits used over and over strengthen, those that are not used are dropped resulting in “pruning”

Neglect Impedes Brain Development § Limited exposure to language, touch or social interactions § Emotional or cognitive neglect § Structural Changes § Lack of brain growth beyond effects of poor nutrition § Neuronal death beyond “pruning”

Fun Facts § Average number of neurons in the human brain § 100 billion § Average number of neurons in an octopus brain § 300 million § Rate of neuron growth during development of a fetus (while in the womb) § 250, 000 neurons per minute

§ CEREBRUM § The cerebrum is the largest part of the brain and controls all conscious thoughts, experiences, and actions. § Speech, memory, and problem solving § Its outer folded layer is called the cerebral cortex.

§ THALAMUS § Connects the spinal cord and cerebrum. § Controls expression of emotions.

§ PITUITARY GLAND § The pea-sized gland that releases the hormones that regulate growth and sexual development. § Found in the center of the skull

§ CEREBELLUM § The cerebellum is the second largest part of the brain. § It controls posture and balance. Replace this with, "It also helps with the timing and coordination of our movements, making them smooth and precise.

§ BRAIN STEM § It controls processes basic for survival, such as heart rate, breathing, digestion, heart rate, and sleep. § It is the main route of communication between the rest of the brain.

§ Spinal Cord § Transmits information from the body to the brain and from the brain to the body. § It coordinates the activities of the left and right sides of the body and controls simple reflexes that do not involve the brain.