Intro to neural control systems

Question 1

Where is grey matter found and what is its role?

Answer 1

Packed in dendrites
-Role is involved in processing information

Question 2

Where is white matter found?

Answer 2

In bundles of axon
-This carries information to dendrites

Question 3

What is the CNS composed of?

Answer 3

Spinal cord and brain

Question 4

What do afferent nerves carry in the peripheral nervous system?

Answer 4

Afferent: carries information to brain

Question 5

What do efferent nerves carry in the peripheral nervous system?

Answer 5

Efferent: carries (motor outputs): information from brain to effectors
(glands, skeletal/smooth muscles)

Question 6

What is the somatic nervous system?

Answer 6

Includes all nerves that run to and from the spinal cord and send information to and from the muscles and senses

Question 7

What is the autonomic nervous system?

Answer 7

Component of the peripheral nervous system that regulates physiological processes including heart rate, blood pressure, respiration, digestion and sexual arousal

Question 8

What are the thinking parts of the brain?

Answer 8

Cerebral cortex and hippocampus are the thinking part of the brain

Question 9

What connects the two hemispheres of the brain?

Answer 9

corpus callosum connects the two hemispheres – axons running through

Question 10

What makes up the diencephalon?

Answer 10

divided into 4 main parts
-Epithalamus
-Thalamus
-Subthalamus
-Hypothalamus

Question 11

What does the thalamus relay to and from?

Answer 11

Thalamus relays signal to and from the cerebral cortex

Question 12

What do sensory pathways do in the thalamus?

Answer 12

Sensory pathways synapse in the thalamus on the way to the cortex

Question 13

What is the hypothalamus the master controller of?

Answer 13

Hypothalamus is the master controller for homeostasis

Question 14

What does the hypothalamus lihk and control?

Answer 14

Links neural and endocrine systems
-Controls the system that regulate the internal environment via the ANS and the systems that generate the sleep-wake cycle

Question 15

What does the brainstem manage and via what system?

Answer 15

Manages visceral function via the autonomic nervous system

Question 16

What does the brain stem work with to fine-tune motor control?

Answer 16

Works in partnership with cerebellum to fine tune motor control

Question 17

What turns into the spinal cord as it extends beyond the skull?

Answer 17

The medulla turns into spinal cord as it extends beyond the skull

Question 18

What does the spinal cord carry?

Answer 18

Carries afferent and efferent axons for somatic and autonomic nervous systems

Question 19

What is the resting membrane potential?

Answer 19

The Resting Membrane Potential (RMP) is a potential difference between the inside
and outside of the membrane

Question 20

What allows current flow across the nerve?

Answer 20

Potential difference allows current flow

Question 21

How is the resting membrane potential generated?

Answer 21

• We use ATP to drive Na out of
  cell and import K
• 3 K in and 2 Na out – leaving
  deficit of negative charge inside of
  cell
• This causes the formation of a concentration
  gradient
• More positive inside
  momentarily
• Allows opening of K channel
  which allows K to flow out of the
  cell via. diffusion due to
  concentration created
• More positive outside

charge inside a cell

• This gives the potential
  difference
• Na can’t flow back in
• You will get to a point where K
  can no longer be diffused due to
  build-up of positive charge
• However, equilibrium can be
  reached ~ -70mV which maintains the
  RMP

Question 22

What is the resting membrane potential?

Answer 22

-70mV

Question 23

What is the size of the membrane potential determined by?

Answer 23

The size of membrane potential is
determined by size of concentration
gradient

Question 24

What is the normal range of K in plasma

Answer 24

About 3-5mM

Question 25

What can happen if K+ levels are altered?

Answer 25

If that changes e.g. kidney disease (hyperkalaemia), tissue damage – dead tissue
releasing K – it turns into medical emergency
o If concentration gradient gets smaller, then all membrane potential of cells
will get smaller too
o Can disrupt your neural activity
o Disrupt you heart activity

Question 26

How do nerves depolarise?

Answer 26

• How to depolarise the cell – we
  need positive charge into the cell
• Na channels closed at rest but
  when action potential fired it
  opens (it is voltage gated meaning
  it will open due to change in
  membrane potential) – flows into
  the cell
• To bring back to rest you need to open
  more K channels to allow K to flow out
  the cell causing repolarisation
• Then hyperpolarisation

Question 27

What is the size of the synaptic cleft?

Answer 27

20-50nM between presynaptic and postsynaptic cell.