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Parasympathetic system is located in the:
Midbrain, medulla, sacral cord.
What's the difference between tonic and reflex?
- Tonic: one nerve does more or less
- Reflex: dual innervation - para and symp work together or against each other.
1. Baroreceptor reflex is (antagonistic/complementary/synergistic)?
2. Where are the baroreceptors located?
3. Where are the control centers located?
- 1. Antagonistic. Para tells AV node to slow down. Symp tells AV node to speed up. Dual innervation.
- 2. Carotid sinus and aortic arch
- 3. Medulla oblongata.
What's the difference between cooperative and complementary effects in regards to the reflex?
Complementary causes similar effects. Cooperative is when both para and symp work together to have different effects to cause the same function.
1. Is the simple stretch control in the urinary bladder complementary, cooperative or antagonistic?
2. Explain it.
3. Can it be complementary? How?
- 1. Antagonistic.
- 2. Sympathetic system usually causes bladder wall relaxation and closing of the internal sphincter. Parasym causes contraction of bladder wall and opening of the internal sphincter.
- 3. Yes. When bladder is full, the parasympathetic system causes reflex contraction of the bladder muscle and relaxation of the internal sphincter so that bladder can empty. Though it isn't essential, sympathetic system can increase the tone of the bladder wall and thus cause emptying as well.
1. Are glial cells excitable?
2. Can neurons make more neurons?
3. Can neurons regenerate themselves?
4. Can Glial cells make more glial cells? If so, how?
5. T/F. There are more neurons than glial cells.
6. Glial cells support neurons like the glue they are, yes?
- 1. No.
- 2. No.
- 3. Yes.
- 4. Yes. Mitosis.
- 5. LIES!! ...False.
- 6. Yes
Name the different types of glial cells, what they do and what's cool about them and where they're found.
- 1. Schwann cells: PNS. Make myeline. One axon per schwann cell. There may be more than one schwann cell per axon.
- 2. Satellite cells: PNS. Structural support.
- 3. Oligodendrocytes: CNS. Make myelin. Many axons mylinated per oligodendrocyte. Many oligodendrocyte per axon.
- 4. Astrocytes: CNS. Most numerous of all neuroglial cells. They provide nutrition, contact blood vessels, repair damage, limit transmitter diffusion, uptake transmitters, synthesize transmitter and buffer extracellular potassium. They do not have action potentials.
- 5. Microglia: CNS. Phagocytic cells (tiny garbagemen)
- 6. Ependymal cells: CNS. line ventricles of the brain and central canal of spinal cord.
1. What are nissl bodies?
2. Where are they found?
3. How'd you find 'em?
- 1. Form of rough endoplasmic reticulum.
- 2. Cell bodies of nerve cells.
- 3. They stained dark grey!
1. What type of neuron is most common? How many dendrites and axons does it have? Example?
2. How many dendrites and axons does a bipolar neuron have? Where is one found?
1. Multipolar. Several dendrites and one axon. Example is alpha motor efferent neuron
What disease, discussed by Dr. D'Souza, causes degeneration of the myeline sheath?
T/F. The amount of neurotransmitters that are released form the terminal is directly proportional to the amount of Ca++ entering the terminal.
What two ions are responsible for IPSPs?
K+ (efflux) and Cl- (influx)
What is the difference between temporal and spatial summation?
- Temporal: repetitve EPSPs from same knob.
- Spatial: simultaneous EPSPs from different knobs.
1. What are gap junctions?
2. T/F. They are electrically coupled and unidirectional.
3. What three places area they found in?
4. T/F. Gap junctions are the major form of communication.
- 1. Membranes of adjacent cells are very close together and channels exist between the two membranes, allowing communication.
- 2. False, they are electrically coupled and bidirectional.
- 3. Glial cells, areas in brain where two-way communication is needed and embryonic nervous tissue.
- 4. False, chemical synapses are the major form of communication between cells.
1. T/F. Chemical synapses are unidirectional.
2. What are the three types of chemical synapses and which is the best?
- 1. True
- 2. Axodendritic (where competition may occur), Axoaxonic (where short circuiting is possible) and Axosomatic (which is the best because it's closest to the initial segment.)
1. How and where is CSF formed?
2. Where does it drain?
- 1. CSF is formed in the choroid plexus which are located on top of each ventricle. Na+ and Cl- ions in blood pass through the highly selective membrane made of choroid epithelial cells (regulated by tight junctions) and water follows due to the osmotic gradient created. No macromolecules allowed.
- 2. CSF drains into the arachnoid villi (same as arachnoid granulations only granulations are a bigger version. Remember in GA, we had to locate the pits for the arachnoid granulation?). Arachnoid villi are litte projections from the arachnoid membrane that protrude into the venous sinuses of the brain to drain the CSF. They are one-way valve that have direct contact with veins like the emissary vein or meningeal vein and they push CSF back into the blood stream.
1. Capillaries in the brain are walled-in by __________ cells bound together by _______ junctions and thus forming the _______ ________ _________.
2. T/F. Gasses, lipid soluble substances, glucose, some amino acids and blood proteins are allowed to pass through the blood brain barrier either by diffusion or by specialized transport systems.
3. What are the breaks in the blood-brain barrier called?
- 1. endothelial, tight, blood-brain barrier.
- 2. False. Gasses, lipid soluble substances, glucose and amino acids can pass through specialized transport systems. Blood proteins and other macromolecules cannot.
- 3. Circumventricular organs.
1. What is laterality of function?
2. What is the left hemisphere good at?
3. What is the right hemisphere good at?
- 1. Laterality of function means that certain functions are best done by one hemisphere of the brain. This does not mean that the other hemisphere cannot carry out those functions, it just means that one hemisphere is better at it.
- 2. Left hemisphere --> Symbolic / Analytical (language, intellectual, math).
- 3. Right hemisphere --> Associative (aesthetics, senses, mood, music, spatial ability etc)
In the brain:
1. What are gyri?
2. What are sulci?
3. What are fissures?
- 1. elevations of folds or crests
- 2. grooves
- 3. deep sulci that divide the hemisphere into lobes.
1. What is the primary function of the frontal lobe?
2. What area on the frontal lobe specializes in this function, in other words, neurons for this function are found where?
3. What other minor functions does the frontal lobe carry out?
4. T/F. Each area of the precentral gyrus controls a particular muscle.
- 1. Voluntary motore control
- 2. Precentral gyrus.
- 3. Integrates sensory and motor input, personalty, concentration (wrinkle your forehead when you concentrate, use the frontal lobe), planning, decision making, verbal communication, inhibition of inappropriate behavior, visual sensations (associates what you see with other things).
- 4. True.
1. What is the main function of the parietal lobe?
2. Where are the neurons for this function located in the parietal lobe?
3. What happens when there's damage to the parietal lobe?
- 1. Interpretation of cutaneous and muscle sensation (somatosensory- touch/pain etc. Knowing spatial placement of limbs etc), understanding and formulating speech to express thoughts and emotions, texture and shape interpretation (reach into a box and feel an object)
- 2. Post-central gyrus aka somatosensory cortex.
- 3. Decreased spatial orientation, loss of body image on the contralateral side.
1. What is the main function of the temporal lobe?
2. What disease is associated with damage to the temporal lobe and what are some of its symptoms?
- 1. Auditory. Also responsible for emotional behavior and memory of sights and sounds. The hippocampus lies in the temporal lobe and it's pertinent to long term memory.
- 2. Kluver-Bucy syndrome: Placidity loss of fear, decreased aggressiveness, visual agnosia (can't describe what you're looking at), orality (tendency to put objects in your mouth.
1. What is the main function of the occipital lobe?
1. Vision and coordination of eye movement. It works with the frontal lobe to correlate visual images with previous visual experiences.
What is the purpose of the insular lobe?
Memory encoding, integration of sensory with visceral responses (coordination of cardiovascular response to stress)
This lobe has a low threshhold for seizures. Seizures in this lobe may produce hallucinations of sights, sounds and smells.
The cells of the cortex are divided into 6 layers. What are the functions of these layers?
- I-III --> association and process, connections between cortical layers.
- IV --> Input from thalamus.
- V-VI --> Output. Connections between subcortical structures, send axons to distant part of the nervous system.
They go I-VI from outer surface of the brain to the inner white matter.
1. What is special about cortical cells in the same vertical column?
2. What makes cortical mapping possible?
- 1. Each column acts as a module or circuit that analyzes input to detect or extract specific features of the stimulus. The columns are specialized.
- 2. The cortex can be mapped because the cells of the cortical vertical columns share functions
1. T/F. Caudate and lentiform nucleus are part of the cerebrum.
1. False. They are part of the basal ganglia which is not part of the cerebrum.
1. What is the function of the basal ganglia?
2. What is the function of the caudate nucleus?
3. What is the function of the lentiform nucleus?
- 1. Motor learning and motor control. Controls movements indirectly by making synapses with other regions connecting with the extrapyramidal tracts. Responsible for body posture, direction, force and speed of movement.
- 2. Caudate --> Cognitive control. It helps cortex execute subconscious but learned patterns of movement. (When the Titanic was sinking, Jack Dawson's caudate nucleus helped him to save his own caudate by going to the upper decks instead of going to the lower flooded decks. He didn't consciously have to ponder whether he should go drown or not)
- 3. Lentiform --> Learned, complex movement such as writing the alphabet or drilling a prep. Right now, we're trying to get our lentiform to learn how to prep teeth.
Parkinson's disease is caused by the degeneration of what parts of the brain and what neurotransmitter is it associated with?
Basal ganglia and substantia nigra (where dopamine is made...decrease in dopamine related to Parkinson's)
Name three other basal ganglia disorders.
- 1. Huntington's Chorea: sudden, jerky, purposeless movement.
- 2. Athetosis: worm-like movement of hands, neck, face, tongue or other body parts.
- 3. Hamiballismus: wilf flailing.
What is the purpose of the thalamus?
Thalamus is the switchboard. It's the sensory and motor relay and integration center, processing the sensory and motor info and channeling it to appr
This area of the brain is a complex network of nuclei and fibers located in the brain stem and project to all parts of the brain. It is also involved in arousal (alert consciousness)
The hypothalamus serves as a vital interface between what two areas of the brain and thus helps maintain what two bodily functions?
Interface between the endocrine system and the reticular formation. It helps maintain menstrual and sleep/wake cycles.
1. Chronic stimulation of what causes overeating?
2. Osmoreceptors in the hypothalamus stimulate thirst and ADH release from what?
- 1. Lateral hypothalamus
- 2. Posterior pituitary.
What are all the functions of the hypothalamus?
- Maintaining sleep/wake cycles, menstrual cycles, emotions (anger, pain, fear), homeostatsis (body's thermostat), hunger/thirst, integrative functions include autonomic, somatic and hormonal pathways, controls visceral organs via other brain regions and the autonomic nervous system.
- Hypothalamus is a very versatile organ.
Limbic system is also known as the ______________.
What are the structures of the limbic system?
- 1. Cingulate Gyrus
- 2. Amygdala
- 3. Hippocampus
- 4. Septal Nuclei
Which organ can interact with the external environment via the limbic system?
T/F. The papez circuits communicate with the thalamus, hypothalamus and the cerebral hemispheres.
False. Papez circuits are connections between the thalamus and hypothalamus, not cerebral hemispheres.
Now onto Miss Cerebellum, the secretary. Miss Cerebellum controls ___________ functions primarily. She organizes all input from different areas of the brain into smooth and _________ movement.
- 1. Motor.
- 2. Coordinated. (Cerebellum co-ordinates, never initiates.)
Cerebellum recieves input from ___1___, ____2___ and ____3______. It sends output to _____4_______ aka _____5______ via the ______6_______. It also has connections to ____7____ and ____8_______.
- 1. Joints
- 2. Tendons
- 3. Muscle receptors
- 4. Motor cortex
- 5. Precentral gyrus
- 6. Thalamus
- 7. Brain stem
- 8. Spinal cord.
1. T/F. The cerebellum controls motuion on the ipsilateral side.
2. T/F. The cerebellum influences motor activity directly.
- 1. True.
- 2. False. It influences motor activity indirectly via motor nuclei and the basal ganglia.
1. Where are the corpora quadragemini located?
2. What are they and what are their functions?
- 1. Midbrain
- 2. They are four elevations. Upper two are superior colliculi involved in visual reflexes, as in tracking objects. They also help you look like less of a pug and more of a human.
- The lower two are inferior colliculi and they relay auditory input to other parts of the brain. They help you determine where the loud semi is coming from so you can get your butt out of its way before you become a road stain.
1. Cerebral peduncles, located in the ___________, contain what?
2. What part of the midbrain is connects to the cerebrum and cerebellum? What is it involved in?
3. Substantia nigra connects to what part of the brain? What is substantia nigra involved in?
- 1. Midbrain; contain ascending and descending fiber tracts.
- 2. Red nucleus; involved in motor coordination.
- 3. Basal ganglia; involved in motor coordination and also dopamine production.
Disorders of movement such as ataxia, dysmetria and dysdiadochokinesia are most likely due to the damage of what part of the brain?
In the brain stem:
1. Midbrain is primarily responsible for?
2. Pons is primarily responsible for?
3. Medulla is primarily responsible for?
- 1. It's a relay center for sensory and motor pathways and contains nuclei as well as ascending and descending fiber tracts.
- 2. It's involved in control of different autonomic functions and contains relay stations for activities initiated at higher levels of the brain.
- 3. All ascending and descending tracts pass through the medulla, many of them cross (the crossing forms structures called pyramids). Medulla also has nuclei for cranial nerves (8-12). Medulla genreally controls functions which are confined to one organ such as heart rate, respiration, BP etc. Each organ has its own center in the medulla.
What two functions sets pons apart from the midbrain?
Unlike the midbrain, Pons has nuclei for cranial nerves 5, 6, 7 and 8, and it has two respiratory centers (apneustic and pneumotaxic). It's like the midbrain because it connects to the cerebellum and has ascending and descending tracts.
Name the three important centers located in the medulla and what they do.
- 1. Vasomotor center: regulates blood vessel diameter
- 2. Cardioinhibitory center: slows heart rate and decreases force of contraction
- 3. Medullary respiratory center: regulates patterns of breathing.
Where is the reticular formation? What is its purpose?
Reticular formation is located within the midbrain, pons, medulla, thalamus and hypothalamus. It is activated in a non-specific fashion by sensory information, its fibers project diffusely and result in non-specific arousal of the cortex to incoming sensory info. Its continuous transmissions activate the brain. There's no brain function without it. It's the core of the CNS. It organizes basic behavioral patterns involving the body as a whole.
It adds method to the madness.
What's the cauda equina?
Tail of the horse. It's all the nerves that come out of the bottom of the spine to the sacrum. The parasympathetic nerves, Sacral 2, 3, 4 are part of the cauda equina.
In the spinal cord, the ascending and descending tracts are arranged into 6 columns of white matter, what are they called?
1. Can the spinal cord have local segmental reflexes?
2. Are there some reflexes that are taken care of by the spinal cord before the brain even catches up?
3. T/F. Spincal cord has reflex centers.
1. Name the sensory tracts in the spinal cord and describe their path.
2. Name the motor tracts in the spinal cord and describe their path.
3. Which tract never crosses over?
4. Which tract crosses over in the spinal cord?
5. Which two tracts cross over in the medulla?
- 1. a. Spinocerebellar - goes from muscle spindle to cerebellum. (Cerebellum is motor, muscles are all about motor, so it goes from muscle spindle to cerebellum)
- b. Spinothalamic - goes pain and temperature receptors to thalamus and cortex (post-central gyrus).
- c. Dorsal column-Medial leminiscal - goes from joint and touch receptros to thalamus and cortex (post-central gyrus)
- 2. a. Corticospinal - Pyramidal tract - Motor cortex (precentral gyrus) to motor neurons of skeletal muscle.
- b. Rubrospinal - red nucleus gets info from the cerebrum and cerebellum and sends it down the spinal cord to muscles.
- 3. Spinocerebellar.
- 4. Spinothalamic.
- 5. Medial leminiscal and corticospinal.
1. In muscle reflex, which fiber is the sense organ and which is the contractile unit?
2. T/F. Ia afferent nerve goes from extrafusal fiber to the spindal cord.
- 1. Intrafusal fiber aka muscle spindle is the sense organ and extrafusal fiber is the contractile unit.
- 2. False. It goes from intrafusal fiber to the spinal cord.
1. What happens when gamma nerve fiber is stimulated?
2. T/F. The more the 1a afferent fiber fires, the less the intrafusal fiber stretches.
- 1. Muscle spindle stretches --> 1a efferent gets a signal --> tells alpha motor neuron to contract extrafusal fiber --> muscle contracts. Gamma increases senstivity of the stretch reflex. 'Lil intrafusal fiber is too weak to contract a muscle on its own.
- 2. False. Stretch of the intrafusal fiber is directly proportional to 1a afferent's firing.
1. What are the two types of intrafusal fibers?
2. What's the difference between the two types?
- 1. Nuclear bag and nuclear chain.
- 1. Nuclear bag detects fast, dynamic changes in muscle length and tension. Chain detects static changes. (Unrelated analogy: If you stretch a metal chain, it doesn't go anywhere, it's static! Plastic bag full of hair can be pulled in different directions, it's dynamic.)
1. The golgi tendon organ has what sort of afferent fibers?
2. Are they excitatory or inhibitory to the 1a?
3. T/F: Inverse stretch reflex is a defensive mechanism.
- 1. 1b.
- 2. Inhibitory.
- 3. True.
What is the difference between reciprocal innervation and crossed extensor reflex?
Reciprocal innervation flexing one group of muscles while extending another group. Crossed extensor reflex does the same thing for the most part only on different limbs, flexing one group of muscle in one limb while extending another group in another limb.
What are the three cortical motor areas and what are their functions?
- 1. Primary motor cortex - Discrete. Recieves sensory input and gives feedback. Muscles for more skilled movement have areas of greater representation.
- 2. Supplementary - less defined.
- 3. Premotor cortex - motor association area; capable of coordinating movements involging many muscles simulataneously.
1. What area of the brain is responsible for posture and controls vestibular and neck relfexes (balance)?
2. What area is used for learned patterns of behavior and is a co-initatior?
3. What area is best informed of all motor structure and is a coordinator of muscle movement?
- 1. Brain stem.
- 2. Basal Ganglia
- 3. Cerebellum.
1. What is the law of specific nerve energies?
2. What is the law of projection?
3. Which law is responsible for Phantom Limb Syndrome? Which method of sensory coding is responsible for Phantom Limb Syndrome?
4. What is meant by the term "receptor's modality"?
- 1. The sensation characteristic of a sensory neuron is the one produced by its adequate stimulus.
- 2. No matter where along the sensory pathway a neuron is stimulated, the cortex will percieve the same sensation.
- 3. Law of Projection. Labelled line.
- 4. Receptor's modality is the type of sensation it elicits (vision, hearing, pH of CSF etc)
1. Stimulus strength depends on: ?
2. How do you tell where a stimulus is?
3. How do you know what a stimulus is?
- 1. Firing frequency (stronger stimulus cause faster firing rates), recruitment (stronger stimulus make more receptors fire) and threshold stimulus which is the weakest stimulus that can be detected (more sensitive receptors get stimulated and stimulate less sensitive ones so e'rybody fires!)
- 2. Each neuron recieves info from a particular area and projects to a spot on the cerebral cortex (remember homonculus). Laternal inhibition (tune everyone else out to say "I'm right here!" When one neuron is fired, others around it are inhibited)
- 3. Labelled line: regardless of how it's stimulated, the message recieved by CNS is the same.
1. Which receptor chiefly mediates fine touch and vibration?
2. Is it rapidly adapting?
3. Does it have myelinated afferent fibers?
4. What is its mechanism?
5. Where is it found?
- 1. Pacinian corpuscle.
- 2. Yes.
- 3. Yes.
- 4. The receptor is encapsulated in layers. When stimulated, the outer layer deforms and in turn, deforms the inner layer which deforms the nerve terminal. If the outer layer stays deformed, the inner layer arranges itself. A steady discharge is generated by vibration only.
- 5. Muscle and subcuteanous layer.
1. What does Ruffini corpuscle detect?
2. Where is it found?
3. T/F. Ruffini's corpuscle is slowly adapting and thus it's unmyelinated.
4. What's special about its capsule?
5. Where are Ruffini's corpuscles found that are relevant to dentists?
- 1. Pressure and sustained touch.
- 2. Dermis and joint capsules.
- 3. False. Ruffini's corpuscle is slowly adapting but it's myelinated.
- 4. It's capsule is filled with liquid. Collagen strands connect it to skin and nerve terminal, deformation of skin can fire the neurons.
- 5. PDL. Gives tooth directional sensitivity.
1. What do Meissner's Corpuscle and Merkel's disc do?
2. Which is rapidly adapting and which one isn't? Are they both encapsulated and myelinated?
3. What else detects touch? Are they rapidly adapting or slow? What specifically do they detect?
- 1. They both detect touch, together they're important for localizing touch and determining texture. Meissner's - Tactile descrimination and location. Merkel's - skin indentation.
- 2. Meissner's is rapidly adapting, Merkel's is slow. Meissner's is encapsulated, Merkel's isn't. They're both myelinated.
- 3. Hair follicle receptors. Rapidly adapting. Initial contact and direction of movement on skin.
1. T/F. Warm fibers are more numerous than cold.
2. T/F. C-Fibers and A-delta fibers detect warmth.
3. T/F. A-delta fibers are myelinated.
4. T/F. As body gets warmer, the A-delta fibers fire more and more.
5. The viscera generally has what type of endings?
- 1. False.
- 2. False. Only C-fibers detect warmth. Cold is detected by both but primarily A-delta.
- 3. True. C-fibers aren't.
- 4. False. A-delta are primarily for cold, as body gets warmer, cold fibers fire less.
- 5. C-fibers.
What two types of receptors are multi-branched?
Ruffini Corpuscle and A-delta fiber have multi-branched endings.
During what range are changes in temperature easiest to detect? What is name for this range?
31-36 degree C. Comfort zone.
1. Which fibers are receptors for fast pain?
2. On which tract does slow pain travel?
3. Does slow pain elicit the withdrawal reflex?
4. Does slow pain have more or less projects from thalamus to the parietal lobe?
- 1. A-delta.
- 2. Spinoreticulo-thalamic (lateral division?)
- 3. No, fast pain does.
- 4. Less.
1. What kind of a function is discriminative pain?
2. What kind of a function is affective pain?
1. What are the two theories for referred pain? Explain them.
2. T/F. Phantom limb is a form of referred pain.
- 1. a. Convergence: somatic and visceral afferents converge on the same spinothalamic neuron, thus the pain generated in the viscera feels like it came from the skin.
- b. Facilitation: Impulses from visceral lower somatic's threshold and thus anything activity in the somatic area that would've died out is actually passed onto the brain.
- 2. False. Phantom limb is associated with labelled line and law of projection.
1. Pain activates a path in the ____________ grey matter of the ________ and ______________.
2. Which nucleus does this area synapse on and where is it located?
3. Which tract does the neurons from this nucleus synapse with?
4. Name two opioid peptides.
5. Where are pain signals inhibited?
- 1. a. Periaquaductal
- b. Midbrain
- c. Upper pons.
- 2. Raphe nucleus located in the lower pons and upper medulla.
- 3. Spinothalamic.
- 4. Ekephalins and beta-endorphins.
- 5. Pain signals are inhibited where they synapse in the dorsal horn (dorsal = sensory, stop sensing pain)
What's the Gate Theory?
Gate theory is distraction. You activate the larger fibers with touching or shaking so that the smaller ones are inhibited.