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Terms in this set (90)
Electrical difference between 2 places
Uses Electrical changes from channels
Where does Action Potential begin?
Graded Potential start from
Dendrites. Will create an action potential if big enough
- based on chemical changes
More Na+ is located
Outside the cell
More K+ is located
Inside the cell
Amino acids also inside the cell
Inside the cell is more
Negative (A-) than outside. Some K+ is leaking out.
To make more flow of Action Potential,
Open the channels
K+ are slow to close. Can reach another AP, but need a harder stimulation
- when we want to turn cell off
Open K+ channels, graph declines.
Start of Graded Potential
Open Na+ channels, enter the cell. Inside becomes more positive, must reach higher than threshold point to create action potential.
Absolute Refractory Period
Na+ can't open again or make another action potential
Relative refractory period
Can make a new action potential, but with difficulty. Only if stimulation is hard enough
Cytoskeletal elements, gives cell its shape
Space between 2 neurons
Na+ goes in, intensity gets less intense as it moves down the cell. No more sodium channels to open.
- Calcium enters the cell, channels open, vesicles release neurotransmitters
- K+ leaves, Na+ enters. Makes inside cell more positive. Creates a small depolarization current
Release neurotransmitters. Key in lock to open channels
Adding graded potentials coming from many places
Adding graded potential coming in too quickly
Too much excitation in the brain. Traffic brain
More positive on the inside, getting closer to the threshold
Take away from the threshold. Open a chloride channel, allow to flow in (Cl-) when Na+ is outside the cell
- More K, amino acids inside the cell
Nodes of Ranvier
Gaps needed to have channels uncovered.
Wraps around the axon. Insulation, like electrical coverings that covers the cord.
Plasma membrane is oily.
Outermost layer-contains nucleus
Jumping down the axon. Only found in Schwann cells
PNS, Schwann cells on the axon can regenerate. Form a tube and tells where to grow: Regeneration tube
Survival, warning sign. To stop the action. Carried on axons with heavy myelin
Don't use it anymore. Takes time to get to nervous system, unmyelinated axons.
Don't make myelination tube/regeneration tube.
- Sends off branches to wrap up several axons through extensions.
Demyelination, short circuits. speed of action potential slows down
Regulate chemical environment of nervous tissue.
Neurons don't like fluctuations, prefer stable conditions. Acts as a cell in between to regulate.
- tight blood vessels in brain
Blood brain barrier
Brain likes chemically stable environment
Act as a phagocyte, serves as protective immune function
- BBB: WBC aren't enough because of the barrier
Cerebral spinal fluid
In brain ventricles.
Surrounding brain, goes down spinal cord.
- Stable, acts as cushioning, lightens brain, nourishes brain, allows for stable chemical environment for brain
At the edges of ventricles. Supporting cells. Have cilia that move cerebral spinal fluid
Secretes and reabsorbs things- regulates content of the CSF.
Choroid plexus: have ependymal cells + blood vessels. Creates cerebral spinal fluid, regulates content.
Instead of jumping across signals, travels continuously
What allows for faster action potentials
Size of axon- bigger axon is faster
Temperature- colder temperature slows it down
Rate of action potential determines intensity
How neurotransmitter is removed
1. Enzyme gets rid of it
3. Neuron that releases neurotransmitter can suck it back up: Reuptake
4. Neurotransmitter diffuses away by itself
Rough ER: for protein synthesis.
Located in the cell body of the neuron
Cortex of brain
Gray matter: contains cell bodies. Looks darker
Just contains axons, lighter
Inside CNS. Distinct collections of axons
Collection of deep gray matter with specific function
Protection of brain & spinal cord
Separates 2 halves
Tough, like leather.
Underneath dura mater. Has blood
Layer with spider webs. Space underneath- Subarachnoid space: where cerebral spinal fluid circulates
Where CSF comes out, goes back into the blood
Thin & delicate, follows every gyrus & sulcus in the brain
Aren't getting rid of CSF fast enough
Cushioning around spinal cord, filled with fat
Cervical enlargement & Lumbar enlargement
Contains more nerves, goes to arms & legs
Tip end of spinal cord
Big collection of spinal nerves at the end- tail of a horse
Separates Cerebellum from brain
Separates temporal lobe from brain
Separates frontal lobe from parietal
Primary Motor area. In front of central sulcus
Primary Somatosensory area. Behind central sulcus. Receives sensory input from your brain. Ex: poke your finger
Motor speech, frontal lobe
Between Temporal & parietal lobe: speech comprehension
White matter in cerebellum
Connects 2 hemispheres. Commissure
2 sides communicate with each other. Each side does different things. CC shares information with the other side
Where things cross over to the other side. Action potentials from here to breathe, makes you inhale. Worse to damage this than pons. What makes you breathe.
More life support system. Senses the stretch, says its time to stop breathing, stops the action potential in Medulla
Internal GPS. sesnse of where things are around you. 2 bumps: visual & auditory reflex
Anything with "Thalamus"
The gateway to the brain, sensory relay. Takes something and sends it on.
Regulates homeostasis: thirst, hunger, sex drive, hormones, body temperature. Controls the pituitary gland.
Includes pineal gland: makes melatonin
Also known as a stroke. Blood is cut off to brain and brain tissue may die as a result.
Two ways to have a CVA:
Ischemic-A blockage/clot blocks a blood vessel. Hemorrhagic-A blood vessel burst in the brain and bleed inside the brain.
This type is worse, because direct contact with blood is toxic to brain tissue and will kill it. Blockages on the other hand may go away or can be dissolved with medications given promptly
traumatic brain injury that can affect behavior. Usually temporary; nothing obvious on brain scans
"Bruised brain". When there is actual bleeding in the brain
Inflammation or infection of the brain itself
Commissural tracts (commissures)
Tracts that connect structures on opposite sides (left and right) of the central nervous system.
Connections between structures on the SAME side. For example, tracts that connect the occipital and parietal lobes on the same side of the brain would be association tracts.
Begin in the brain but then leave to proceed down the spinal cord. Motor pathways originating in motor cortex on the pre-central sulcus project out of the brain and go down the spinal cord when they make connections onto other motor neurons (in the anterior gray) that go to your muscles.
Decussation (crossing over) of the medulla oblongata
Where sensory and motor pathways going to and from the body cross to the other side. This explains why the right side of your brain senses and controls the left side of your body. The relevant tracts decussate (cross over) to the other side in the medulla.
1. The poliovirus is a highly contagious virus that can cause paralytic polio in some infected individuals.
2. In paralytic polio, the virus preferentially destroys motor neurons in the anterior horns of the spinal cord. In the image (above), it is clear that the anterior horn on one side of the spinal cord is greatly diminished in size. T
3. The destruction of these motor neurons will cause the skeletal muscles formerly controlled by those nerves to lose their connections to the nervous system.
4. Paralysis results.
5. Poliomyelitis is easily prevented through childhood vaccinations.
1. The Latin word limbus means belt in English. The limbic system consists of a diverse array of deep brain structures arranged in a semicircular belt-like fashion.
2. Also known as the "emotional brain", because many of its structures play a role in emotion.
3. Note the following structures in the limbic system: Olfactory bulbs (receive and transmit sense of smell to the brain)
Hippocampus (a temporal lobe structure involved in memory)
Hypothalamus (responsible for regulating drives, hormones and homeostasis).
4. For thought: Out of all our senses, the sense of smell is often cited as being the most powerful sense for triggering memory and emotion. Why is this? It is because the sense of smell is directly tied into the limbic system along with the memory centers in the hippocampus.
5. For thought: Why is it that our emotions can affect things like appetite and sex drive? It is because the hypothalamus is a part of the limbic system. Our emotions can have a real affect on the body by influencing the hypothalamus.
1. Plays a crucial role in maintaining behavioral arousal and consciousness
2. Sends information from eyes and ears to cerebellum
3. Helps with tone and posture (motor function)
4. Can block some pain signals to brain
5. Exerts some control over thalamus and regulates how much sensory information reaches the cortex. This can regulate how attentive or alert we are or whether we are sleeping. Injury to this function can cause irreversible coma or inability to sleep.
6. Habituation: Filters out repetitive, meaningless stimuli while remaining sensitive to others. Example: Being able to sleep through the sound of car traffic in a big city, but promptly waking up if you hear your baby crying.
7. Everyone's capacity to filter out sensory information varies. A person with a very strong reticular formation filter is not bothered by a lot of extraneous outside information. This type of person may crave stimulation at a party, for example. Such persons are often labeled as "extroverts". Other individuals who do not filter as much sensory information may be overwhelmed by too much sensory input at a loud party. It is possible that the strength of the filtering capacity of the reticular formation plays a role in determining certain personality types.
1. Older texts refer to them as "ganglia"
2. Deep nuclei at base of forebrain (cerebrum)
3. Involved in procedural learning, routine behaviors, eye movements.
4. Some are also part of limbic system
5. Some help to regulate motor functions to make movements "smooth"
6. Many exert an inhibitory effect
Example: The substantia nigra (see diagram) is an inhibitory basal nucleus that helps to inhibit unwanted action potentials coming from motor cortex. This nucleus essentially functions as an "off switch" to make sure your muscles don't move unless you want them to move. If this nucleus degenerates or is damaged, you begin to have unwanted muscle movements (Parkinson's disease)
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