Podcast
Questions and Answers
Nerves are stringlike bundles of axons and dendrites that come from the spinal cord and are held together by ______.
Nerves are stringlike bundles of axons and dendrites that come from the spinal cord and are held together by ______.
connective tissue
The Central Nervous System is made up of neurons located in the ______ and spinal cord.
The Central Nervous System is made up of neurons located in the ______ and spinal cord.
brain
The resting membrane potential of a neuron is approximately ______ millivolts (mV).
The resting membrane potential of a neuron is approximately ______ millivolts (mV).
-70
If the depolarization is strong enough to raise the membrane potential to around ______ mV, the threshold is reached.
If the depolarization is strong enough to raise the membrane potential to around ______ mV, the threshold is reached.
During depolarization, sodium ions rush into the neuron, causing rapid ______ of the membrane potential.
During depolarization, sodium ions rush into the neuron, causing rapid ______ of the membrane potential.
After sodium channels close, ______ channels open, allowing potassium ions to flow out of the neuron.
After sodium channels close, ______ channels open, allowing potassium ions to flow out of the neuron.
In some cases, potassium channels remain open briefly, causing hyperpolarization before returning to ______.
In some cases, potassium channels remain open briefly, causing hyperpolarization before returning to ______.
Neurotransmitters are chemicals used for communication between neurons during mental or physical ______.
Neurotransmitters are chemicals used for communication between neurons during mental or physical ______.
Genes are chains of chemicals arranged like rungs on a twisting ______.
Genes are chains of chemicals arranged like rungs on a twisting ______.
A human brain weighs about ______ grams.
A human brain weighs about ______ grams.
Glial cells are the most numerous brain cells, about ______ billion.
Glial cells are the most numerous brain cells, about ______ billion.
A neuron is a brain cell with two specialized ______ for receiving and transmitting signals.
A neuron is a brain cell with two specialized ______ for receiving and transmitting signals.
Dendrites are branchlike ______ that receive signals from other neurons.
Dendrites are branchlike ______ that receive signals from other neurons.
The axon is a single threadlike structure that carries signals ______ from the cell body.
The axon is a single threadlike structure that carries signals ______ from the cell body.
Presynaptic terminals look like tiny ______ that store neurotransmitters.
Presynaptic terminals look like tiny ______ that store neurotransmitters.
The Peripheral Nervous System (PNS) consists of nerves located throughout the body except in the brain and ______.
The Peripheral Nervous System (PNS) consists of nerves located throughout the body except in the brain and ______.
Flashcards are hidden until you start studying
Study Notes
Overview of the Human Brain
- Genes consist of chemical chains that influence the development of the brain and body, with 20,000 to 25,000 identified.
- The mature human brain weighs approximately 1,350 grams and has a pinkish-white color, resembling firm JELL-O.
- Contains about 1 trillion cells and has three major divisions.
Key Cell Types in the Brain
- Glial Cells: Approximately 900 billion; provide structural support, insulation for neurons, and release chemicals that affect neuron growth.
- Neurons: About 100 billion; specialized cells designed for receiving and transmitting electrical signals.
Neuron Structure and Function
- Dendrites: Branched extensions from the cell body that receive signals from other cells.
- Soma (Cell Body): Egg-shaped structure that maintains neuron function and produces necessary chemicals.
- Axon: Long structure that transmits signals away from the cell body.
- Presynaptic Terminals (End Bulbs): Store neurotransmitters for communication with adjacent cells.
- Synapse: Microscopic gap (20-30 billionths of a meter) between neurons where signal transmission occurs.
Nervous System Components
- Peripheral Nervous System (PNS): Comprises nerves outside the brain and spinal cord, composed of bundled axons and dendrites; nerves can regenerate if damaged.
- Central Nervous System (CNS): Composed of neurons located in the brain and spinal cord.
Information Transmission in Neurons
- Resting Potential: Neurons maintain a stable membrane potential of about -70 mV; the inside is negatively charged due to potassium ions and negatively charged proteins.
- Threshold: If membrane potential reaches -55 mV, voltage-gated sodium channels open, initiating an action potential.
- Depolarization: Sodium ions influx leads to rapid membrane potential change, reaching +30 mV.
- Repolarization: Sodium channels close, potassium channels open to restore the negative potential.
- Hyperpolarization: Potassium efflux may overshoot, temporarily decreasing membrane potential below baseline.
- Refractory Period: A brief pause after neuron firing during which new action potentials cannot occur.
Neurotransmitters
- Approximately a dozen different chemicals vital for neuron communication that facilitate mental and physical activities.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
