mechanics of the nervous system

Question 1

CNS: spinal cord

Answer 1

• conduit for sensory and motor info (brain to body and body to brain)
• protected by vertebrae
• afferent neuron acons enter cord in dorsal root and terminate in dorsal horn
• efferent neurons have a cell body in ventral horn and axons leave cord ventral root

Question 2

PNS: function

Answer 2

• connects CNS to limbs and organs via cranial and spinal nerves
• carries info from environment to CNS (afferent/sensory neurons)
• carries info from CNS to muscles and glands (efferent/motor neurons)

Question 3

PNS: nerves

Answer 3

• neuron axons grouped into bundles
• 43 pairs:
• 12 cranial nerve pairs
• 31 spinal nerve pairs

Question 4

PNS: cranial nerves

Answer 4

• 12 pairs
• 10 –> brainstem
• 1 & 11 –> forebrain
• information between the brain and body above the neck

Question 5

PNS: spinal nerves

Answer 5

• 31 pairs
• each pair is associated with a segment of spinal cord
• spinal nerves can contain sensory and motor fibres

Question 6

somatic nervous system

Answer 6

• voluntary control of body movement
• receives sensory information and controls spinal nerves that innervate skin, joints, and muscles
• afferent neurons carry sensory into from skin
• efferent neurons control skeletal muscles

Question 7

autonomic nervous system

Answer 7

• controls involuntary functions and internal environment
• afferent neurons carry sensory infro from internal organs to CNS
• efferent neurons control smooth muscle, cradiac muscle and glands

Question 8

sub divisions of autnomic nervous system

Answer 8

1. sympathetic nervous system
2. parasympathetic nervous system
3. enteric nervous system

Question 9

ANS: symphathetic ns

Answer 9

• any response for activities which expand energy
• coordinates fight or flight response

Question 10

ANS: parasympathetic ns

Answer 10

• activities involved with increase in the body’s supply of stored energy
• coordinates rest and relax resposne

Question 11

ANS: enteric ns

Answer 11

• lines your gastrointestinal tract from oesophagus to rectum
• controls digestion

Question 12

gut-brain axis

Answer 12

• two way communication system between brain and the gastrointestinal tract
• gut microbiota regulates brain function by preserving the CNS immune homeostasis
• prevents neuroinlammation and degradation

Question 13

neurons

Answer 13

• transmit info to other neurons, muscle or gland cells
• 80% of neurons are in the brain

Question 14

sensory neurons

Answer 14

• part of PNS
• contain sensory receptors to detect sensory changes
• sends info about changes to CNS

Question 15

motor neurons

Answer 15

• part of PNS
• synapses to skeletal muscle to command muscle/glands to release hormones
• relays signal from CNS to PNS
• dendrites and cell body in CNS, axon enters PNS

Question 16

interneurons/relay neurons

Answer 16

• in CNS
• recipes info from sensory neurons and passes it onto motor neurons
• integrate signal: inputs from multiple afferent neurons
• change signal: interneurons can provide excitatory or inhibitory

Question 17

neuronal membrane

Answer 17

• two layers of lipif molecules: hydrophillic and hydrophobic
• barrier: water soluble molecules cannot pass

Question 18

fluid environment

Answer 18

• contians ions - intraceullualr fluid and extracellular fluid
  cations:
• sodium is mostly extracellular
• potassium is mostly intracellular
  anions:
• chloride is mostly extracellular
• organic ions are only inracellular

Question 19

movement of ions

Answer 19

ions move because of:
- concentration gradient (via diffusion)
- electrical force (via electrostatic pressure)