KNOW THESE BETTER

Question 1

Metencephalon - made up of what 2 brain structures?

Answer 1

• Pons: houses many fibre tracts and part of reticular formation
• Cerebellum: 50% of all neurons in the brain; Massively connected to cortex – multiple cerebro- cerebellar systems; Involved in movement and timing

Question 2

Mesencephalon (midbrain) - composed of:

Answer 2

the tectum (“roof”), which contains nuclei that receive and relay:
- visual information (superior colliculi)
- auditory information (inferior colliculi)

the tegmentum (“floor”), which contains nuclei related to:
- motor function (substantia nigra and red nucleus)
- pain (periaqueductal grey)

Question 3

Structure that can span across multiple sections

Answer 3

Reticular formation

Question 4

Reticular formation

Answer 4

• midbrain, pons, medulla
• Reticulum means “little net”
• In the myel-, met- and mesencephalon (midbrain + hindbrain)
• Many nuclei that play roles in arousal, attention, cardiac and respiratory reflexes, and other jobs

Question 5

Diencephalon - composed of…

Answer 5

• thalamus
• hypothalamus

Question 6

Diencephalon - Thalamus

Answer 6

• 2-lobed structure
• Different types of nuclei – some process and relay info between receptors and cortex
• **Nuclei may be specific to one sense or combine information from many senses (EX: if someone suddenly threw a frisbee, you would both be able to SEE it and HEAR it)
• Thalamus & cortex are closely connected

Question 7

Thalamo-cortical loops and consciousness

Answer 7

• Thalamus and cortex are closely connected - important in how we see the world as a unified place
• General anesthetics tend to act upon the nonspecific nuclei of the thalamus (as well as other structures)
• Abnormal synchronization in the thalamo-cortical network can cause absence (“ab-sonce”) seizures

Question 8

The hypothalamus

Answer 8

• Hypo = under, hence, UNDER the thalamus in the brain
• Plays an important role in behaviours such as feeding, sex, sleeping, temperature, emotion, and movement
• Acts upon the body’s endocrine (hormone) system via the pituitary gland (instructs the endocrine system)

Question 9

Telencephalon involves which 3 structures

Answer 9

1. Basal ganglia
2. Limbic system
3. Cerebral cortex

Question 10

Basal Ganglia

Answer 10

• “Lower knots”
• Collection of nuclei highly connected to cortex, thalamus, and midbrain
• Involved in movement and learning

Question 11

Limbic system - made up of what 2 structures (amongst other structures):

Answer 11

• Hippocampus (“seahorse”) – plays a role in spatial memory
• Amygdala (“almond”) – plays a role in emotion

Question 12

Cerebral cortex - Sulci and Gyrus

Answer 12

Sulci deep enough to indent the ventricles are also called fissures

• Sulcus: bottom of wrinkle
• Gyrus: top of wrinkle

Question 13

Is the cortex just one layer?

Answer 13

NO - made of up to 6!

Question 14

Cerebral cortex - 90% of the human cerebral cortex is…

Answer 14

isocortex (sometimes called neocortex) = 6-layered

Question 15

Cerebral cortex - 10% of the human cerebral cortex is…

Answer 15

• …allocortex = <6 layers
• Hippocampus, olfactory (piriform) cortex

Question 16

What is the role of the meninges?

Answer 16

Three layers of membranes known as meninges protect the brain and spinal cord

Question 17

What 3 layers make up the meninges?

Answer 17

• The delicate inner layer: pia mater.
• The middle layerz; the arachnoid, a web-like structure filled with fluid that cushions the brain
• The tough outer layer: the dura mater.

Question 18

• ANATOMY: NEURONS -

Question 19

Does AP occur anywhere along the axon?

Answer 19

• Unmyelinated axons have Na+ channels (Nav) all along their surface
• Myelinated axons not all covered by myelin; rather, have little bubbles and gaps between myelinated areas, leaving the axon exposed
• Nav only at the nodes of Ranvier: where myelin is interrupted

Question 20

The synapse - receiving…

Answer 20

• postsynaptic neuron
• Postsynaptic neurons have a variety of receptors that fit, like a lock and key, with specific neurotransmitters
• When NTs bind to a corresponding receptor, they trigger changes that push the charge of the postsynaptic cell up (towards depolarizing) or down (towards hyperpolarizing)

Question 21

Neurotransmitters can be (3 types)

Answer 21

• Excitatory: make the receiving neuron more likely to fire an action potential
• Inhibitory: make the receiving neuron less likely to fire an action potential
• Modulatory: trigger other changes

Question 22

Neurotransmitter cleanup

Answer 22

• Diffuse away
• Broken down by enzymes
• Reuptake
  ○ By presynaptic neuron
  ○ By glia

Question 23

Reuptake inhibitors

Answer 23

• Serotonin (5-HT) & norepinephrine (=noradrenaline) are neurotransmitters
• These drugs are generally used to treat depression, anxiety, and pain

Question 24

Other cell in the nervous system

Answer 24

• Glia
• “glue,” “sticky”
• 10x more numerous than neurons

Question 25

4 subtypes of glia

Answer 25

* Oligodendroglia * Schwann cells * Microglia * Astroglia

Question 26

Oligodendroglia

Answer 26

wrap around the axons of neurons in **CNS**, forming **many** myelin sheaths per cell

Question 27

Schwann cells

Answer 27

wrap around the axons of neurons in **PNS**, forming **one** myelin sheath per cell

Question 28

Microglia

Answer 28

* (smallest type of glial cell) respond to injury & disease, engulfing debris and triggering immune response * Only in CNS

Question 29

Astroglia

Answer 29

are the largest glial cells: * Support endothelial cells of the BBB * Provide nutrients to neurons * Maintain ion balance in CNS * Repair after injury * Communicate with neurons and glia * Control and maintain synapses Only in CNS

Question 30

Which of the 4 subtypes of glial cells is in the PNS?

Answer 30

Schwann cells

Question 31

NEUROLOGICAL EXAM

Question 32

3.Motor Function - Key features to examine:

Answer 32

* Gross appearance of muscle * Muscle **tone, strength** * Strength: how much force can a muscle exert, when you’re trying to exert force * Muscle tone: how active is a muscle at rest

Question 33

Upper motor neurons originate in _ or _ and use _

Answer 33

motor cortex, brainstem; glutamate

Question 34

Upper motor neuron lesions can lead to

Answer 34

* Weakness * Spasticity - Muscle “catches”; ridgity * Hyperreflexia * Retained primitive reflexes (e.g., grasp, suck, snout)

Question 35

Lower motor neurons originate in _ or _ , _ , and use _ (incl. motor cranial nerves)

Answer 35

spinal cord or brainstem, innervate muscles or glands, and use acetylcholine

Question 36

Lower motor neuron lesions can lead to:

Answer 36

* Weakness * Hypotonia (low tone) * Hyporeflexia * Atrophy * Fasciculations: fine movements of the muscles under the skin

Question 37

4.Somatosensory

Answer 37

Somatosensory Function * Temperature * Pain * Vibration * Proprioception * Touch

Question 38

Somatosensory - issues with touch

Answer 38

* **Astereognosis** = inability to recognize objects by touch * (Subtype) **Agraphesthesia** = inability to recognize letters/numbers by touch * > both point to sensory cortex of parietal lobe

Question 39

5.Coordination - Quick, alternating movements can test

Answer 39

* Dysmetria > impairment performing accurate movements * EX: putting the cap on a pen

Question 40

5.Coordination - Romberg’s test

Answer 40

* balance with eyes open vs closed * +ve Romberg points to cerebellar damage

Question 41

5.Coordination - Pronator drift

Answer 41

Pronator drift = rotation and vertical motion of arm - EX: in the neurological exam video - when eyes are closed, hands held out either rotate (pronates) or one raised above the other - Points to damage to the pyramidal tract (efferent fibres from cortex to brainstem or spinal cord)