Lecture 1

Question 1

Which is faster: The nervous system or The endocrine system? Why?

Answer 1

The nervous system, because it uses action potentials which travel through myelinated axons that might reach 120 m/s and unmyelinated axons from 2-5 m/s.

Question 2

Which has a higher gain: The nervous system or The endocrine system? Why?

Answer 2

The endocrine system, because the hormones try to bring back blood pressure to almost 100 with zero error; the game will be infinite. (Nervous system might bring it back to 105 = -3 gain)

Question 3

What does the nervous system affect?

Answer 3

Skeletal muscles and glands

Question 4

What does the endocrine system affect?

Answer 4

Growth, metabolism, and reproduction.

Question 5

If the signal does not reach the cerebral cortex, what happens?

Answer 5

The signal will not consciously be perceived.

Question 6

What is the central nervous system (CNS) composed of?

Answer 6

1) Brain

2) Spinal cord

Question 7

What goes to the CNS from the PNS?

Answer 7

Afferent (Ascending) division:

1) Sensory stimuli
2) Visceral stimuli

Question 8

What goes out of the CNS to the PNS?

Answer 8

Efferent (descending) division:

1) Somatic nervous system (motor/voluntary)
2) Autonomic nervous system (involuntary)

Question 9

What senses changes in the environment?

Answer 9

Receptors

Question 10

Receptors are also called ___, because:

Answer 10

Transducers; They convert any type of energy (action potential).

Question 11

Receptors attach with what kinds of neurons?

Answer 11

Afferent neurons.

Question 12

What are tracts?

Answer 12

Collection of axons in the CNS.

Question 13

What are nerves?

Answer 13

Collection of axons in the PNS.

Question 14

Where are the cell bodies of afferent neurons found?

Answer 14

In the dorsal root ganglia.

Question 15

If the signal doesnt ascend, then what connects afferent neurons with efferent neurons?

Answer 15

Interneurons

Question 16

What are the sensory divisions of the nervous system?

Answer 16

1) Tactile
2) Visual
3) Auditory
4) Olfactory

Question 17

What are the integrative divisions of the nervous system?

Answer 17

1) Information processing

2) Memory creation

Question 18

What are the motor divisions of the nervous system?

Answer 18

Respond to and move about in our environment.

Question 19

What does corticospinal mean?

Answer 19

From the cerbral cortex to the spinal cord.

Question 20

Where did the signals go to synapse with the motor neurons?

Answer 20

The anterior horn of the spinal cord (alpha motor neuron)

Question 21

What is an alpha neuron?

Answer 21

Big and myelinated neuron.

Question 22

What is the muscle tone?

Answer 22

Minimal contraction found in the muscle

Question 23

What are the 2 paths that signals can take?

Answer 23

1) Sensory -> Interneuron -> Motor

2) Sensory -> ascends CNS (brain) -> motor

Question 24

Interneurons are responsible for:

Answer 24

1) Integrating afferent information and formulating an efferent response
2) Higher mental functions associated with the mind and memory

Question 25

Most of the neurons found in the CNS are:

Answer 25

Interneurons

Question 26

What are the characteristics of interneurons?

Answer 26

1) Small 2) Highly excitable 3) Outnumber other neurons (interneurons > afferent (sensory) > efferent (motor)

Question 27

What are the types of sensory receptors?

Answer 27

1) Pain and temperature (free nerve endings) 2) Pressure (Pacinian corpuscles) 3) Touch (Meissener’s corpuscle) 4) Muscle (Muscle spindles) 5) Joints (Kinesthetic receptors; proprioceptors)

Question 28

Where does the sensory division start?

Answer 28

From the sensory receptors

Question 29

Where does the motor division start?

Answer 29

Cerebral cortex

Question 30

Which part of the muscle does the motor division go to?

Answer 30

Extrafusal muscle fibers

Question 31

Where is the primary somatosensory cortex located?

Answer 31

On the postcentral gyrus.

Question 32

Sensory signals usually stop at the ____, so it is the relay station for almost all sensations except ____.

Answer 32

Thalamus; olfaction.

Question 33

What are the three levels of CNS function/organization?

Answer 33

1) Spinal cord level 2) Lower brain level 3) Higher brain (Cortical) level

Question 34

Which level is present in primitive or lower animals?

Answer 34

Only the spinal cord level

Question 35

What does the spinal cord level contain?

Answer 35

1) Walking circuits 2) Withdrawal circuits 3) Circuits for reflex control of organ function

Question 36

What do we test when we test the reflexes?

Answer 36

The integrity of the spinal cord

Question 37

What does the lower brain level contain?

Answer 37

1) Medulla oblongata 2) Pons 3) Midbrain

Question 38

What does the lower brain level control?

Answer 38

Subconscious body activities: 1) Arterial pressure 2) Respiration 3) Equilibrium 4) Feeding reflexes 5) Emotional patterns

Question 39

What is the Higher brain (Cortical) level?

Answer 39

1) A large memory storehouse | 2) Essential for thought processes

Question 40

Does the cortex function alone?

Answer 40

No, it always functions in association with lower brain centers.

Question 41

What is the neuron?

Answer 41

The structural and functional unit of our nervous system

Question 42

What are the three major components of a neuron?

Answer 42

1) Soma: Body 2) Axon: Extends from Soma to terminal part of effector 3) Dendrite: high resistance projections from the soma to the sensory portion of the neuron

Question 43

What is the first part of a neuron called?

Answer 43

Axon hillock

Question 44

What is found at the end of the axon?

Answer 44

Axonal terminals or axonal buttons

Question 45

What do axonal buttons contain?

Answer 45

Neurotransmitters

Question 46

Neurons have all the cell organelles except ____.

Answer 46

Centrioles

Question 47

Why do neurons lack centrioles?

Answer 47

Because they dont divide/regenerate.

Question 48

Why is the CNS enclosed by bony structures (skull and vertebral column)?

Answer 48

For protection.

Question 49

What is the function of the cerebrospinal fluid (CSF)?

Answer 49

Shock absorber

Question 50

Why are dendrites unable to produce action potentials?

Answer 50

Because they have a very low density of sodium voltage gated channels.

Question 51

Where is the action potential best produced?

Answer 51

Axon hillock (first unmyelinated part of axon)

Question 52

Which has the highest density of sodium voltage gated channels?

Answer 52

Axon hillock

Question 53

The CNS is also protected by meninges. What are the three layers from outside to inside?

Answer 53

1) Dura mater 2) Arachnoid mater 3) Pia mater

Question 54

Which cells produce the myelin sheath in the CNS?

Answer 54

Oligodendrocytes

Question 55

Which cells produce the myelin sheath in the PNS?

Answer 55

Schwann cells

Question 56

What are the nodes of Ranvier?

Answer 56

Unmyelinated areas interrupting myelin.

Question 57

What is the anterior motor neuron?

Answer 57

A kind of neuron that contains many synapses: 1) Axosomtic with soma 2) Axodendritic with dendrites 3) Axoaxonal with axons

Question 58

What kind of conduction is one-way conduction/synapse?

Answer 58

Chemical conduction/synapse

Question 59

What kind of conduction is two-way conduction/synapse?

Answer 59

Electrical conduction/synapse

Question 60

Why is chemical synapse one-way?

Answer 60

Because there are no receptors on the pre-synaptic neuron (only post-synaptic).

Question 61

Which type of conduction is more common in the CNS?

Answer 61

Chemical synapse (one-way conduction)