Neurons Also called nerve cells Highly specialized to transmit messages from one part of the body to another Size varies in length from microscopic to 3-4 feet! ◦ The longest is from the spine to the big toe
Dendrite Soma (cell body) Nucleus Myelin sheath Schwann cell Node de Ranvier Axon terminal Axon
Dendrites Incoming messages toward cell body (soma) come here Hundreds of branching dendrites in one neuron
Axon One axon per neuron Message travels along axon, away from cell body, to axon terminal
Axon Terminal End of neuron Contain sacs that have neurotransmitters When impulses reach here, they stimulate the release of NTs into the extracellular space
Synaptic cleft Tiny gap that separates each axon terminal from the next neuron Synaptic cleft **Adjacent neurons never touch each other
Myelin Sheath Protects axon and increases rate of message Multiple Sclerosis (MS) is a disease that occurs when the myelin sheath is destroyed ◦ Symptoms: person loses ability to control muscles and becomes disabled; no cure
Neurotransmitter A chemical signal that relays information between neurons Released from axon terminal into the synaptic cleft Picked up by dendrites on adjacent neuron ◦ NTs in dendrites causes information to travel through cell body and down axon to the axon terminal and process repeats
Common Neurotransmitters NTs have different effects on our bodies We will learn about 5 different ones **Forget about the inhibitory/excitatory box. Use that box for more space to take the notes!
Dopamine Effects: emotion and subconscious skeletal muscle movements Decreased amounts lead to Parkinson’s Increased amounts = Schizophrenia
Serotonin Regulates mood, appetite, sleep, muscle contraction, memory and learning. Decreased amounts = depression
Epinephrine Adrenaline Increase heart rate Participates in fight-or-flight response of the sympathetic nervous system
Endorphins Released by pituitary gland and hypothalamus during exercise, excitement, pain, and consumption of spicy food Work as "natural pain relievers."
Oxytocin Best known for its roles in female reproduction: 1) it is released in large amounts after distension of the cervix and vagina during labor, and 2) after stimulation of the nipples, facilitating birth and breastfeeding, respectively. Recent studies have begun to investigate oxytocin's role in various behaviors, including social recognition, bonding, anxiety, trust, love, and maternal behaviors