Lecture 5: Chemicals of Life Flashcards
What are cells in the nervous system?
- Cells are the basic structural units of all forms of life.
- They are specialised for different functions.
- You can see them under a microscope.
What are the different types of cells involved in behaviour?
- Neurons, glial cells (in the brain)
- Receptor cells (in sensory organs, e.g. rod and cone cell in eye)
- Ganglion cells (neurons clustered in peripheral nervous system, away from the brain)
What is the typical structure of an animal cell?
Each cell has:
- organelles (=specialised structures inside the cell)
- a nucleus containing the DNA (with the majority of genes)
- Cytoplasm
→ All surrounded by a cell membrane
What are neurons?
Electrically excitable cells which transmit signals throughout the body?
- Have similar structures as other animal cells, but also differences
What are receptor cells?
in sensory organs, e.g. rod and cone cells in eye retina or skin receptors for touch
What are ganglion cells?
Specific type of neurons clustered in peripheral nervous system, away from the brain
What is a nucleus?
Genes are located on chromosomes (DNA coiled around histones) located in the cell nucleus
What is a gene?
Gene = a length of DNA that contains the information for constructing a particular protein
What is gene expression?
A process of producing a protein from DNA
What are the two phases of gene expression?
- Transcription (from DNA to RNA)
- Translation (from RNA to protein)
What are proteins?
Gene products
- large, complex molecules that do most of the work in cells
- Enzymes (make biochemical reactions happen)
- Messengers (chemical communication across the body)e.g. Hormones
- Structural componentse.g. membrane channels, receptors for neurotransmitters
What are the ions in the intracellular and extracellular space?
- Ions are small particles created when you dissolve solid chemicals in watery solutions.
- They are the same chemical elements but in a different form.
- The structure of the atom changes and becomes charged negatively or positively depending on their characteristics.
What is a neuronal membrane?
(At rest ,not during electrical signal)
- Keeps water in or out of cell (insoluble in fat layer)
- Keeps most chemicals in or out of cell (physical barrier)
- Channel proteins pump some ions in and out.
- Other ions go through open channel proteins according to their concentration (from more concentrated to less concentrated).
→ Maintaining a different electrical charge (more negative inside and more positive outside)
What is the electricity of the neuron?
- Neurons are electrically charged.
- They generate electrical currents by changing the imbalances of ions between the intra- and extracellular space.
- As negative and positive charged elements attract each other, the ions move when allowed to go through the cell membrane and by moving they generate electrical impulses.
What are axons?
- Myelin (a fatty substance that does not have the channels/pores for ions) insulates the axon and makes it travel faster.
Duct tape analogy - when you have a broken cable, you fix by wrapping with duct tape to keep all electricity inside
What are synapses?
- At the end of the axon (can be long as in a nerve), the electrical message needs to be transferred to another cell (another neuron, a muscle cell or a hormone-producing organ)
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Neurotransmitters (small molecules related to proteins):
- Acetylcholine (e.g. motor synapses), serotonin (e.g. antidepressant target), glutamate (e.g. generation of electrical signals in the neurons), dopamine (e.g. addiction), GABA (e.g. alcohol)
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Proteins on cell membrane (or nucleus), act as receptors and ion channels
- e.g. target for psychoactive drugs, genetic predisposition to mental illness
