Neurons & Neurophysiology

Question 1

Why do we Have a Brain?

Answer 1

Movement: To predict the Changing Environment

Brain = Predicting Machine > Using info. from Past Experience = Memory

To > Predict Future Events = Intelligence

Learns from Senses > about environment + whether Prediction is wrong

Question 2

What are the Sub-Divisions of the Nervous System?

Answer 2

Question 3

What is the Precentral Gyrus?

(Other Names, Location, Function)

Answer 3

AKA > M1 - BA4 (Primary Motor Cortex)

Located in Frontal Lobe (Ant. to central sulcus)

Function: Voluntary Movement of Skeletal mm.

Question 4

What is the Post Central Gyrus?

(Other Names, Location, Function)

Answer 4

AKA > S1 & BA 3, 2, 1 (Primary Somatosensory Cortex)

Located > Parietal Lobe > Posterior to Central Sulcus

Function > Main Sensory Receptive Area for:

Touch, Proprioception, Nocioception

Question 5

What Makes Up The Diencephalon & What is its Role?

Answer 5

Consists of: Hypothalamus & Thalamus

Hypothalamus > ANS >Control Centre for Basic Bodily Functions: Eating, Drinking, Sleeping

Thalamus > SNS > Relay Centre > Sensory & Motor Input > Regulation of Sleep + Sexual Behaviour

Question 6

What Makes Up the Peripheral Nervous System?

(Hint: How Many Pairs of Nerves)

Answer 6

All Neurons Outside CNS

12 Pairs Cranial (Sensory, Motor, Mixed)

31 Pairs of Spinal Nerves (8,12,5,5,1 > Exit Vetebrae > Arise > Ant. & Post. Horn Cells of Spinal Cord)

Question 7

What Makes Up the Central Nervous System?

+ Main Functions

Answer 7

Brain (Cerebrum, Cerebellum, Brainstem)

& Spinal Cord

Information Relay Centre > Bodily Functions > Homeostasis > Hormone Balance

Movement > Memory > Intelligence

Question 8

What Makes up the Limbic System?

+ Functions of Each

Answer 8

Cingulate Gyrus > Process Emotion & Behavior Regulation

Corpus Callosum > Links L. and R. Cerebral Hemispheres

Hypothalamus > Vital Control Centre Basic Bodily Functions (Homeostasis > Hormone Balance)

Thalamus > Relay Centre Sensory/ Motor Input + Regulate Sleep & Sexual Behaviour

Amagdala > Emotion Regulation (Mental Health)

Question 9

Broca’s Area + Location & Function

Answer 9

> BA 44, 45

> Frontal Lobe > Dominant Cerebral Hemisphere

• Word Formation

Question 10

Wernicke’s Area + Location & Function

Answer 10

> BA22

Superior Temporal Lobe ( Encircles Auditory Cortex > Dominant Cerebral Hemisphere) >

• Language comprehension & Intelligence

Question 11

Auditory Cortex + Location & Function

Answer 11

> BA 41, 42

> Temporal Lobe

Hearing (Process Speech), identify & Localise Sound Sources

Question 12

Function Of Glia?

(AKA Glial Cells, Neuroglia)

Answer 12

• Nutrients for Neurons (Regulate Ion Exchange > Homeostasis)
• Activate Repair Mechanisms

Question 13

Types Of Glial Cells + Functions

Answer 13

Astrocytes > Most Numerous in the brain > Fill spaces between neurons + Support functions

Myelinated Glia > Oligodendroglia (CNS) &

Schwann cells (PNS) > Insulate Axons

Other Non-Neuronal Cells >

• Microglia > Phagocytes (Immune)
• Ependymal Cells (Line Fluid-Filled Ventricles)

Question 14

What is an EPSP? & Give Examples

Answer 14

Excitory Post Synaptic Potential > (Na+ Channels Open)

(Depolarisation of Postsynaptic Membrane > Via Presynaptic Release of Neurotransmitter)

• Acetylcholine
• Noreadrenaline
• Serotonin
• Glutamate and aspartate
• Dopamine (Both Excitory & Inhibitory)

Question 15

What is an IPSP? & Give Examples

Answer 15

Inhibitory Postsynaptic Potential > (K+ Channels Open)

(Hyperpolarisation of Postsynaptic Membrane > Via Presynaptic Release of Neurotransmitter)

• GABA
• Endorphin & Enkephalins
• Dopamine (Both Excitory and Inhibitory)

Question 16

What Increases Action Potential Conduction?

Answer 16

Spread of AP Along Membrane > Myelination

Axonal Excitability >

Axional Diameter (Bigger = Faster)

Number of Voltage-Gated Channels

Nodes Of Ranvier > (Gaps B/w Axons > Allow Ion Exchange (Increase Depolarisation) > Increase Speed)

Question 17

How Do Neurons Communicate?

Answer 17

• Electrical Conduction > Pacemaker Cells (Heart)
• Chemical Conduction >

- Neurotransmitters > Attach to a Target > Elicit Response

Targets: Same Neuron, Different Neuron & Target Organ: Smooth, Cardiac, Skeletal

Question 18

ACh Cycle (Start Presynaptic Terminal)

Answer 18

ACh (Vesicles) > Calcium Influx > Vesicles Diffuse Presynaptic Membrane Via Exocytosis

Synaptic Cleft > Ach either Binds to Ach Receptor to Elicit Response or

> Enzyme Degradation Via > AChE > Cleaved into > Choline + Acetic Acid

Reuptake Choline > Presynaptic Terminal > Choline Symporter

Choline + Acetyl CoA > Synthesised (ChAT) >

ACh Stored > Vesicles

Question 19

Cerebellum (Location & Functions)

Answer 19

Consists of 2 Lobes

Posterior to Brainstem + Inferior to Occipital Lobe

• Reflexive, Involutary Fine Tuning of Motor Control
• Balance & Posture

Question 20

Brainstem (Components, Location, Functions)

Answer 20

Consists of Midbrain, Pons, Medulla Oblongata

Connects Cerebrum to Spinal Cord

Contains Reticular Activating System (RAS) > Network of Neurons Projecting:

Anteriorly > Hypothalamus

Posteriorly > Thalamus & Directly to the Cortex

• ANS Regulation
• Hearing
• Balance

Question 21

Name the Protective Structures of the Brain

Answer 21

Cranium > (Bony Outside Layer) Foramina for Nerves + Blood Vessels to Exit

Meninges > Membranes Surrounding Brain + Spinal Cord

• Dura Mater + Arachnoid Mater + Pia Mater

Cerebrospinal Fluid (CSF) + Ventricular System

Question 22

Cerebral Arteries + Supply

Answer 22

Anterior: Frontal & Parietal Lobes

Middle: Supplies Temporal & Frontal Lobes

Posterior: Supplies Occipital Lobe