Test 1 Flashcards
What are the two categories of cells of the nervous system? What do they do?
Neurons: receive and transmit information
Gila: exchange chemicals with adjacent neurons, do NOT transmit over long distances, Support, protect, and neurish neurons
What is notable about the plasma membrane of nerve cells?
- separate inside and outside of cell
- small uncharged molecules move freely across: H2O, O2, CO2
- charged ions pass through protein channels: Na, K, Ca, Cl
What are the four major structures of a neuron and what do they do?
- Dendrites: branching fibers, information receivers (many)
- Soma: cell body, nucleus, ribosomes, mitochondria
- Axon: thin fiber, information sender (one)
- Presynaptic terminals (end bulbs): swelling at the tip of axon, axon releases chemicals at synaptic gap
What are the four important structures in the neuron soma?
- Nucleus structure that contains chromosomes
- Mitochondria: powerhouse of the cell
- Ribosomes: site of protein synthesis
- Endoplasmic Reticulum: network of thin tubes that transport newly synthesized proteins
What are the important structures, actions, and a disease associated with the axon?
- Mylin sheath: covers the axon: insolates, and increases action potential speed
- Nodes of Ranvier: interruption in myelin sheath/ short unmyelinated sections, facilitates rapid conduction of nerve impulses
- Saltatory conduction: “jumping” of action potential/impulse from node to node along myelinated axon
- Multiple Sclerosis: loss of myelin along axon preventing movement (propagation of APs down an axon
What are the types of neurons?
Sensory
- afferent: brings info to structure
Motor
- efferent: brings info away from structure
Interneurons
What is muscle memory?
A clearer path in the brain made by repitition
What are the facts about glia cells?
(Greek for Glue)
- 10th of the size of a neuron
- 10X more numerous than neurons in the brain
- Takes up same space as neurons
What are Astrocytes?
(Star-shaped) wraps around synaptic terminals
- Synchronize axon activity enabling them to send messages in waves
- Removes waste material created when neurons die
“Stars” star-shaped, are synchronized in the sky
What are Oligondendrocytes?
- Surrounds and insulates certain axons in brain & spinal cord
- Builds myelin sheaths around axons in the brain and spinal cord
“legal”- attorney brain & backbone
What are Schwann cells?
- Surrounds and insulates certain axons in the periphery of the body
- Builds myelin sheaths around axons in the periphery of the body
What are Radial Glia?
During embryonic development
- Type of astrocyte that guides migration of neurons
- Type of astrocyte that guides the growth of axons & dendrites
Radial tires migrate
What are microglia?
- Proliferate in areas of brain damage
- Removes toxic materials
Microfiber towel clean-up
What is the blood-brain barrier?
***
- Endothelial cells in the brain that are so tightly joined that most molecules cannot pass between them
- Keeps most viruses, bacteria and harmful chemicals out of the brain
Why do we need a blood brain barrier?
- Damaged cells do not regenerate
- Need to minimize the risk of brain damage
What molecules can cross the Blood Brain Barrier?
1) Small uncharged molecules:
- O2, CO2, H2O
2) Molecules that dissolve in fats of capillary wall
- psychiatric dugs
- abused/ street drugs (nicotine, heroine, marijuana)
- Vitamin A & D
What is Active Transport?
A protein-mediated process that pumps necessary and useful chemicals from the blood to the brain
What chemicals pass through the blood-brain barrier by active transport?
- Glucose
- Amino acids
- Thiamine/other vitamins/iron
- Certain hormones
Why might alcoholics have a vitamin B1 (thiamine) deficiency?
- Poor diet
- Impaired absorption
What does a vitamin B1 deficiency lead to?
- inability to use glucose
- leading to neuron death
- leading to Korsakoff’s Syndrome
What is Korsakoff’s Syndrome?
Severe memory impairment which might cause the person to confabulate
What does it mean to confabulate?
Making up information to fill in gaps
What is a nerve impulse?
- Electrical message transmitted down the axon
- Exchange of chemicals between the inside and outside of cell
What is electrical polarization?
- Difference in electrical charge between two locations
- Inside of membrane has slightly negative electrical potential with respect to the outside