U2: C13: The Nervous System

Question 1

Neuron Structure

Answer 1

(effector cell) sensory neuron -> (effected cell) interneron or motor neuron

Question 2

Mylein Sheath 1. produced by what cell 2. location 3. function 4. affected by

Answer 2

1. Schwann cells (PNS) & Oligodendrites (CNS) 2. Axon, form nodes of ranvier 3. Insulate and are not permeable to ions, therefore ions have to skip myleinated areas and only act at nodes or ranvier making action potential quicker. 4. speed of AP p/1 diameter of axon 1/p of length

Question 3

If stimulus intensity increases how will it change the speed of conduction, amplitude, and frequency?

Answer 3

Neurons are coded by frequency and by the # of action potentials, not by the size of AP. Frequency will increase, but will not affect the size of the amplitude nor speed.

Question 4

Neurons communicate via… (electrical or chemical signals)

Answer 4

Both electrical (action potential = potential difference bw inside and outside of neuron) chemical = neurotransmitters at synaptic terminal. Electrical= all or nothing, and has a absolute and relative refractory period

Question 5

Vocabulary

1. effector
2. afferent\
3. efferent
4. interneron
5. presynaptic terminal
6. postsynaptic terminal
7. polarized
8. depolarized
9. hyperpolarized
10. repolarized

Answer 5

1. neuron that signals to gland or muscle
2. sensory neurons to brain
3. motor neurons from brain
4. reflex arc
5. messenger (synaptic terminal)
6. message receiver (dendrites)
7. resting potential (-70mV) = neg
8. stimulus, rising to action potential (-30mV to +35mV)) = less neg
9. over shoot resting potential (-100mV)
10. returning to resting potential (-70mV)

Question 6

Synaptic traits 1. most are electrical/ chemical 2. rely on .. 3. can be either inhibitory or excitatory by.. 4. To elicit a response from effector cell it depends on…

Answer 6

1. chemical- neurotransmitters 2. Ca2+ to release neurotransmitters (i think??) 3. inhibitory- hyperpolarizing membrane excitatory- depolarizing membrane 4. quantity not quality (number of stimuli not size, or amt of neurotransmitters at effector receptors) Neurotransmitters will be diffused or re-uptaked by synaptic cleft)

Question 7

Neuron propogation

Answer 7

1. @ rest: neuron polarized (-70mV inside)
   
   1. K+/Na+ ATPase (pump 3 Na+ out and 2 K+ in) (influx= in, efflux= out)
2. Stimulus: have to reach meet threshold (-55 mV)
   
   1. Na+ voltage gated channels open (Na+ influx)
   2. Action Potential depolarized (goes to 35mV)
3. After AP: hyperpolarization (-80mV) bc of…
   
   1. Na+ VGC close (@ 35mV)
   2. K+ VGC open (@ 35mV): K+ efflux
4. After hyperpolarization: repolarization (-70mV) bc of…
   
   1. K+ VGC close (@-80mV)
   2. Na+/K+ ATPase

Question 8

Relative & Absolute Refractory period

(draw and label)

Answer 8

Question 9

Nervous System Organization

Answer 9

Question 10

CNS

(white and gray matter)

Answer 10

1. White matter: myleinated = axon
2. Gray matter: nonmyleinated = cell body clusters in CNS = nuclei, and in PNS = ganglia
3. Brain
   
   1. white matter; inside (medulla)
   2. gray matter: outside (cortex)
4. Spinal Cord
   
   1. w: outside
   2. g: inside (dorsal and ventral horns)
      
      1. dorsal root ganglion = sensory neurons
      2. ventral root nuclei = motor neurons

Question 11

CNS/PNS & Spinal cord organization

1. Ganglia location
2. Neurotransmitters
3. Glial cells
4. Somas in Spinal Cord

Answer 11

Question 12

Sensory and Motor neurons

1. Brain
2. Spinal Cord
3. Organ

Answer 12

Question 13

Somatic vs Autonomic nervous system

1. type

2, NT

3. key difference

Answer 13

1. SNS
   
   1. voluntary (unless reflex arc)
   2. acetylcholine for both pre and post synapse
   3. Sensory neuron-> muscle neuron -> goes directly to muscle w/o interneuron
2. ANS
   
   1. involuntary
   2. NT depends on if its sympathetic or parasympathetic
   3. Sensory-> interneurons -> muscle neuron
      
      1. sympathetic: Ach-> norepherine/ epinephrine
      2. parasympathetic: Ach-> Ach

Question 14

Sympathetic vs Parasympathetic Nervous System

Answer 14

PNS of ANS

1. sympathetic: fight or flight- increase heart rate, blood flow to striated muscles, breath rate, pupil dilate (black larger), decrease digestive organ blood flow
2. para: rest & digest- opposite of sym. (innervated by vagus cranial nerve)

Question 15

Forebrain, Midbrain, Hindbrain, Spinal Cord

(parts and functions)

Answer 15

• Forebrain
  
  • cerebral cortex: higher thought
  • corpus collosum: connects the hemispheres
  • cerebrum contains: frontal, parietal, occipital, temporal lobes
  • Thalmus: gateway (all asending sensory travel through thalmus before entering cortex)
  • Hypothalmus: endocrine control
• MIdbrain
  
  • relay point bw peripheral structures and forebrain
    
    • sensory info to midbrain then forebrain
    • motor info from forebrain to midbrain then to hindbrain
• Hindbrain: connects to spinal cord
• Spinal Cord: ervical, throracic, lubar, sacral,

Question 16

Sensory receptors

1. intero
2. proprio
3. extero
4. noci

Answer 16

1. monitor internal env
2. relative position of bodies in dark
3. moitor external env
4. sense pain

Question 17

Chemical receptors x 2

Answer 17

olfaction and gustations (chemicals bind to receptors)

Question 18

Eye

1. light travel order through eye
2. sclera
3. choroid
4. cornea
5. pupil
6. lens
7. photoreceptors

Answer 18

1. light, cornea, pupil/iris, lens, retina, electrical signal
2. white of eye, covering except for the cornea
3. direcly under sclera, supplier of O2 and nutrients
4. bends and focus light]
5. black of eye, opening space behind the iris
6. frocus light, by cillary muscle contraction/relaxation
7. in the retina, they have
   
   1. cones: color
   2. rods: black and white

Question 19

Photoreceptors

Answer 19

1. Cones: color- each type of cone contains a pigment that absorbs a differe wavelength of light
2. rods: black and white, Rhodopsin: only 1 pigment

Question 20

Ear

1. Outer
2. Middle
3. Inner
4. Movement of sound

Answer 20

1. auricle & auditory canal
2. tymphanic membrane (ear drum) & ossicles
   
   1. ossicles- malles, incus, stapes
3. Fluid filled: cochlea & semiciruclar canal
   
   1. cochlea: organ of corti depolarize and cause electrical signal
   2. semicircular canal: orientation and balance due to fluid mvoement.
4. Longitudinal wave-> (auricle -> auditory canal) -> (tymph membrane: vibration bc of pressure of sound wave-> ossicles move back and forth) -> pressure moves through oval window into -> (cochlea: sound wave transfered into fluid wave-> depolarization occurs in hair of organ of corti) -> auditory nerve

Question 21

Resting membrane potential

1. mV
2. Protein tranport type
3. Transport protein function
4. K+ and Na+ concentrations inside
5. K+ and Na+ concentration outside

Answer 21

1. -70mV
2. Na+/K+ ATPase
3. 3 Na+ pumped out, 2 K+ pumped in, Active Transport
4. Inside: [K+] >> [Na+]
5. Outside: [Na+] >> [K+]

Question 22

Initiating action potential

1. How is action potential triggered
2. How is it executed

Answer 22

1. if excitatory input auses axon hillock to depolarize to threshold value (-55mV to -40mV), action potenialwill be triggered.
2. Voltage gated ion channels open.
   
   1. Na+ VGC open, and Na+ influx due to chemical and electrical gradient. Passive transport.

Question 23

Action Potential

1. How did this occur
2. What occurs after action potential
3. How is resting potential reached

Answer 23

1. Na+ VGC opening and Na+ influx : depolarization (+35mV)
2. Na+ VGC close and K+ VGC open: K+ eflux (electrical gradient &chemical gradient): leads to hyperpolarization (-90mV)
3. K+ VGC close. Na+/K+ ATPase repolarizes membrane (-70mV)