Lecture 12 & 13 Questions (few ? q's) Flashcards
draw and label the organization of the CNS at 3 weeks, 4 weeks and 11 weeks
• At the 3rd week of development, the
human brain starts as a hollow tube
• By 4th week it specializes in the anterior
end
- ~4-6 weeks - MASSIVE increase in the # of cells & they are starting to move/migrate around into these new structures
- ~11 weeks - all of this has REALLY started to enlarge & start to BEND & there is a massive increase in the # of cells in the cerebrum
what’s the difference between white and grey matter?
• Grey matter: Unmyelinated cell bodies, axon terminals
and dendrites. Neuronal cell bodies are most often
found clustered together in groups called nuclei, or on
the outer surface of the brain as the cerebral cortex.
• White matter: Myelinated axons.
Where is each (white & grey matter) located in the brain? The Spinal cords?
Brain:
- white matter - inside
- grey matter - outside
Spinal Cord:
- white matter - outside
- grey matter - inside
what are the 4 main support/protective systems for the CNS?
- Bony skull and vertebral column
- Wrapped by three protective and
nourishing membranes called MENINGES - Cerebrospinal fluid (CSF)
- Blood-Brain barrier
Draw and label a cross section (coronal section) of the brain and skull, including the 3 meninges
3 meninges:
- Pia matter
- Arachnoid membrane
- Dura matter
diagrams in notes
list 3 places bleeding can occur between the skull and brain
Traumatic head injury can cause:
– epidural bleeding (between the skull and dura)*
– subdural bleeding (between the dura and arachnoid)
– subarachnoid bleeding (between the arachnoid
membrane and the pia mater)
what are the ventricles filled with?
Cerebrospinal fluid
what produces this (cerebrospinal fluid) substance?
produced by CHOROID PLEXUS in the ventricles
describe the pathway taken by this (cerebrospinal fluid) substance
- Produced by choroid plexus in the ventricles
- Exits brain thru foramen of Magendie and
foramen of Luschka (median and lateral) - Some circulates around the spinal cord, some
circulates into subarachnoid space - Enters arachnoid villi (granulations), and
crosses into venous blood.
what does the cerebrospinal fluid do?
- Helps maintain proper solute concentrations in the interstitial fluid surrounding neurons
- Helps remove waste
- Provides a cushion for the brain
What is the blood brain barrier
• Barrier between the interstitial fluid of the
brain and the plasma.
– Due to the specialized anatomy of blood
vessels in the CNS
– Keeps unwanted materials out, keeps wanted
materials in.
what glia cells help make the BBB
endothelial cells & astrocyte endfeet ?
Is heroin likely to be hydrophobic or hydrophilic?
“Heroin is lipophilic (“lipid-loving”), which means that it can cross the blood-brain barrier more efficiently than its hydrophilic (“water-loving”) metabolite, morphine. Heroin’s lipophilicity manifests itself as rapid Central Nervous System (CNS) absorption, leading to fast onset of effects.” ?
How does glucose get from the plasma to the extracellular fluid in the brain?
Glucose from blood enters the brain by a transport protein. Glucose is the primary energy substrate of the brain. Glucose transport protein (GLUT-1) is highly enriched in brain capillary endothelial cells. These transporters carry glucose molecules through the blood brain barrier. ?? ASK
what kinds of information are processed at the level of the spinal cord
Spinal cord has its own internal circuitry to mediate simple reflexes and generates complicated control programs, such as rhythmic patterns used for walking.
Do the the meninges cover the spinal cord?
yes - the meninges (Pia matter, Arachnoid membrane & Dura matter) surround SC as well so SC gets this protection
what kind of information travels through the dorsal roots? The ventral roots?
Dorsal root: carries sensory (afferent) info to CNS
- enlargement that contains cell bodies of those sensory neurons
Ventral root: carries motor (efferent) info to muscles & glands
list 4 important nuclei in the spinal cord show where they are found
- Visceral sensory nuclei
- neurons part of a local processing circuit - meant to process sensory info that is coming from your viscera (from various organs for ex) - Somatic sensory nuclei
- 2nd order sensory neurons (means they receive a synapse from the 1st order primary sensory neurons)
- cell bodies in there receive some of the sensory info - Autonomic efferent nuclei
- send axons out through ventral routes
- contribute to the autonomic control of your organs - Somatic motor control nuclei (skeletal muscle)
- in the very ventral aspect
- control skeletal muscle
slide 41 for diagram
what is an ascending tract? Descending tract? Show where they are found?
Ascending tract:
- on dorsal surface
- carry sensory info
Descending tract:
- info on axons that will control skeletal muscle & organs
phylogenetically, what is the oldest part of the brain? The newest?
BRAINSTEM is the OLDEST region of the brain
CEREBRUM is evolutionarily, the NEWEST
what does the medulla do? Reticular Formation? Pons? Midbrain?
• RETICULAR FORMATION: – Receives and integrates incoming sensory input. Plays critical role in AROUSAL. – Gives rise to groups of diffuse modulatory neurons*
• MEDULLA contains neuronal clusters
(nuclei) that control HEART and BLOOD
VESSEL function, RESPIRATION, and many
DIGESTIVE functions
• PONS acts as a RELAY STATION for
cerebellum and cerebrum: Plays role
in regulating muscle reflexes involved
in equilibrium and posture
• MIDBRAIN – Critical RELAY for VISUAL and AUDITORY info – Governs movement of the EYES – Gives rise to groups of diffuse modulatory neurons*
What is a diffuse modulatory system? What are the 4 neurotransmitters commonly used? Where are these neurons found?
Diffuse modulatory system: long, slow regulation of behaviour of neurons & its usually through actions of GPCR
4 n.t’s used:
- Norepinephrine
- found: locus coeruleus, hypothalamus, thalamus, & cerebellum - Serotonin
- found: raphe nuclei to basal nuclei - Dopamine
- found: ventral tegmental area, prefrontal cortex & substantia nigra to basal nuclei - Acetylcholine
- found: pontine nuclei, fornix, & cingulate gyrus
slide 47 for a diagram
list 4 common functions of the cerebellum, and one newley described function
• Processes sensory info from muscles, joints, vestibular system, eyes. Integrates position and movement of body with intent to move body.
1. Important in maintaining BALANCE and controls EYE MOVEMENTS.
- Enhances MUSCLE TONE and COORDINATES skilled, VOLUNTARY MOVEMENTS.
- Plays role in PLANNING and INITIATING VOLUNTARY activity by providing input to cortical motor areas.
- Stores PROCEDURAL MEMORIES
• Motor learning.
& • Also has recently discovered function in cognition
list a bunch of functions of the hypothalamus. What do these have in common?
• Brain area most involved in directly
regulating internal environment (WHAT THEY HAVE IN COMMON –> HOMEOSTASIS)
• Functions – Controls body temperature – Controls thirst and urine output – Controls food intake – Controls anterior pituitary hormone secretion – Produces vasopressin & oxytocin (neuroendocrines) – Controls uterine contractions and milk ejection – Serves as a major ANS coordinating center – Plays role in emotional and behavioral patterns, including reproduction, sexual orientation?
what are the 5 major lobes of the cerebrum
• Each half of cortex divided into five major lobes – Occipital – Temporal – Parietal – Frontal – Insular*
given a diagram of a brain, be able to label with the five lobes, and give the function
Diagram slide 54
- Occipital –> vision
- Temporal –> hearing
- Parietal –> sensory
- Frontal –> skeletal muscle movement (motor)
- Insular –> taste & smell
list 5 association areas. Where are they found and what do they do?
- Visual association area –> in Occipital Lobe
- allow higher level processing of the info acquired in the visual cortex - Auditory association area –> in Temporal Lobe
- goes here to understand & process - Sensory association area –> in Parietal Lobe
- understand more of the properties of what you’re touching
- able to associate smooth/rough surface with other simultaneous stimuli & make a judgement as to what that particular stimulus is (ex: different properties of keyboard your touching) - Motor association area (premotor cortex) –> in Frontal Lobe
- involved in planning of movement
- ultimately let you grab your coffee cup
- thinking of picking up coffee mug (help coordinate movement) - Prefrontal association area –> in Frontal Lobe
- “It is involved in the top-down processing of sensory and motor information” ?
what is the corpus callusum?
the central region where neurons pass from one hemisphere of the cerebrum to the other (from textbook)
if you are right handed, where are your language areas likely to be found?
– For most people language processing, math processing occur on the left side
• 95% right handed people left dominant for language
• But only 20% left handed people right dominant for language; many lefties process language on
both sides
– i.e. it’s complicated
– For most people spatial recognition, face recognition, aspects of emotion
processing and artistic functions occur on the right side
what is brocas area? What is wernicke’s area’
BROCA’s area: speech center in the frontal lobe
WERNICKE’s area: 1 of the speech centers of the brain
Sensory input goes from audio or visual cortex to Wernicke’s, then to Broca’s
- following integration b/t these 2 areas, info from Broca’s to motor cortex to initiate spoken or written action
how many cells layers are found in the cerebral cortex? Which layer receives information? Which layer is the main output to distant areas?
6 layers ?
the primary somatosensory cortex is located in a strip of cortex called the postcentral gyrus. It receives information from the body about tactile sensations as well as touch-related sensations like pain and temperature. ?
idk ? ASK
What is the role of the limbic system?
Limbic system links higher processing with primitive emotions such as fear, aggression, reward, social and sexual behaviour.
name three areas the limbic system communicates with
• Includes:
- amygdala (emotion & memory)
- hippocampus (learning & memory)
- cingulate gyrus (emotion)
• Strongly connected with other
areas, such as thalamus,
hypothalamus, and parts of the
midbrain
differentiate between parkinsons disease and Huntington’s disease?
• Parkinsons disease: loss of dopaminergic neurons in BG. Causes tremors, loss of ability to move, cognitive deficits.
– MJF
• Huntington’s disease is loss of cholinergic neurons in BG (this activates the neurons that are lost in Parkinson’s). Causes uncontrolable movements (chorea), loss of coordination, dementia.
what is chorea?
uncontrollable movements (Latin - to dance)
recently Rush Limbaugh accused Michael J fox of pretending to have parkinson’s
disease. Why did he make this accusation? Was he correct?
https: //www.theguardian.com/world/2006/oct/26/filmnews.radio
if you overstimulate/overmedicate you can cause Huntington like symptoms
Rush thought he was “exaggerating his symptoms of his illness”
