Nervous System

Question 1

Function of the Nervous System

Answer 1

• Maintains homeostasis, controls organ systems
• Cognition/memory
• Interprets sensory information about external conditions
• Controls skeletal muscles

Question 2

Neurons

Answer 2

• Processes information

- Sense environmental changes

Question 3

Neuroglia

Answer 3

-Insulate, support, nourish neurons

Question 4

Cell Body

Answer 4

-Contains cell nucleus

Question 5

Dendrite

Answer 5

• Receive information from other cells
• Exert effect on postsynaptic neuron
• Site of graded potential

Question 6

Axon

Answer 6

-Propagation of action potential
Start=Axon Hillock
(where action potential starts)
End= Axon Terminal

Question 7

Multipolar Neuron

Answer 7

• Many dendrites, 1 axon

- Cell body between dendrites and axon

Question 8

Unipolar Neuron

Answer 8

• Dendrites merge into 1 axon
• Cell body on side of axon
• Sensory neurons in PNS

Question 9

Bipolar Neuron

Answer 9

• 1 dendrite and axon
• cell body between dendrite and axon
• Small/rare

Question 10

Anaxonic Neuron

Answer 10

• Can’t distinguish dendrites and axons
• Central cell body
• Occur in brain and sense organs

Question 11

Sensory Neuron

Answer 11

Deliver information from sensory receptors in body to CNS

Question 12

Motor Neuron

Answer 12

Carry movement instructions from CNS to body

Question 13

Interneurons

Answer 13

Forms connections with other neurons

Question 14

Grey Matter

Answer 14

High density of cell bodies

Question 15

White Matter

Answer 15

High density of axons

Question 16

Astrocytes

Answer 16

• Fills spaces between neurons
• Provides structural support
• Regulate chemical environment between neurons
• Maintain blood-brain barrier

Question 17

Ogliodendrocytes

Answer 17

Layers of membrane that insulate axons in CNS

Question 18

Schwann Cells

Answer 18

Layers of membrane that insulate axons in PNS

Question 19

Myelin

Answer 19

• Layers of membrane that insulate axons
• Covering= Myelin Sheath
• Gaps= Nodes of Ranvier
• Increases speed of information transfer down axons (action potential)

Question 20

Neurotransmission

Answer 20

Transmission of information across a synapse

Question 21

Resting Membrane Potential (Neurons)

Answer 21

-70mV

Question 22

Membrane Potential

Answer 22

Positive and negative charges held apart across plasma membrane

Question 23

Sodium Potassium Exchange Pump

Answer 23

• Potassium ions are pumped back into cell and sodium ions are pumped back out of cell
• Ions pumped against their concentration gradient (require ATP)
• Pump is a form of active transport across plasma membrane

Question 24

Passive (Leak) Channels

Answer 24

Always open (sodium and potassium channels)

Question 25

Active (Gated) Channels

Answer 25

- Closed, need stimulus to open | - Open changes membrane potential

Question 26

Chemically-Gated Ion Channel

Answer 26

Chemical opens channel

Question 27

Voltage-Gated Ion Channel

Answer 27

Change in voltage opens channel

Question 28

Mechanically Gated Ion Channel

Answer 28

Mechanical stimulus opens channel (eg: stretching)

Question 29

Action Potential

Answer 29

- An all or none electrical event | - Brief reversal of membrane potential that starts at axon hillock and propagates down the axon to the axon terminal

Question 30

Brief Reversal of Membrane Potential

Answer 30

1) Depolarisation to threshold 2) Activation (opening) of voltage gated sodium ion channels and rapid repolarisation 3) Inactivation (closing of sodium ion channels) and activation of potassium ion channels starts repolarisation 4) Time lag in closing of all potassium ion channels leads to temporary hyperpolarisation 5) Resting potential- both channels close

Question 31

Synapse Activity

Answer 31

Arrival of action potential at axon terminal

Question 32

Neurotransmission at a chemical synapse

Answer 32

1) Arrival of action potential at axon terminal opens voltage-gated calcium channels. Calcium enters presynaptic neuron. 2) Synaptic vesicle containing neurotransmitter fuses to presynaptic neuron and neurotransmitter is released into synaptic cleft via exocytosis. 3) Neurotransmitter binds to receptors on postsynaptic neuron/membrane 4) Receptors on postsynaptic neuron open, enabling a specific ion to move across the plasma membrane

Question 33

Cerebrum

Answer 33

Memory, cognition, control of skeletal muscle

Question 34

Cerebellum

Answer 34

- Monitors and adjusts ongoing movement | - Coordination and timing of movements

Question 35

Spinal Cord

Answer 35

- Transfers movement commands from brain --> body | - Transfers sensory commands from body --> brain

Question 36

Diencephalon

Answer 36

- Thalamus: process sensory info - Hypothalamus: behavioural drives, regulation of body temperature, controls endocrine system and regulates cardiovascular/respiratory/digestive system

Question 37

Midbrain

Answer 37

- Process visual and auditory information - Movement reflex - Maintains consciousness

Question 38

Pons

Answer 38

Subconscious control of skeletal and smooth muscle

Question 39

Medulla Oblongata

Answer 39

Regulates cardiovascular/respiratory/digestive systems

Question 40

Peripheral Nervous System

Answer 40

- Delivers motor commands from CNS --> Body - Delivers sensory commands from body --> CNS - Divided into somatic (skeletal muscle/skin/joints) and autonomic (glands/smooth muscle - Autonomic divided into sympathetic (fight or flight), parasympathetic (rest and digest) and enteric (controls food movement through intestine)