Chapter 12: Nervous Tissue

Question 1

Central Nervous system consists of

Answer 1

the brain and spinal cord

Question 2

Peripheral nervous system consists of

Answer 2

• cranial nerves
• spinal nerves
• enteric plexus in small intestine
• sensory receptors in the skin

Question 3

What are somatic senses

Answer 3

receptors for pain, itch, vibration, pressure (distributed throughout the body)

Question 4

What are special senses

Answer 4

only in specific areas such as eyes (seeing), ears (hearing), tongue (taste)

Question 5

Somatic nervous system (CNS)

Answer 5

skeletal muscle ( able to control)

Question 6

Autonomic nervous system (CNS)

Answer 6

• sympathetic division (fight or flight)
• parasympathetic division (rest and digest)
  ^ smooth muscle, cardiac muscle, and glands
• enteric plexus: smooth muscle and glands of digestive canal

Question 7

Functions of the nervous system

Answer 7

• Sensory: detect changes through sensory receptors
• Integrative: analyze incoming sensory information, store some aspects, and make decisions regarding appropriate behaviours
• Motor: respond to stimuli via effectors

Question 8

Characteristics of neurons

Answer 8

• electrically excitable (like muscle cells)
• do not divide and multiply
• cell body has normal cellular structures

Question 9

Nerve impulse is called an

Answer 9

action potential

Question 10

Parts of a neuron

Answer 10

Dendrites: listen to the gossip
Cell body: has nucleus, mitochondria etc
Axon: can be long or short, Transmit electrical impulses away from the cell body to other cells

Question 11

3 Different structural classifications of neurons (classified based on number of processes extending from cell body)

Answer 11

• Multipolar neuron
• Bipolar neuron
• Pseudounipolar neuron

Question 12

Functional classification of neurons (classified based on direction of nerve impulse propagation)

Answer 12

• Sensory/Afferent neurons: conveys information to CNS
• Motor/Efferent neurons: conveys action potential from the CNS
• Interneurons/Association neurons: process sensory information and elicit motor response

Question 13

Most sensory neurons are…

Answer 13

unipolar

Question 14

Most motor neurons are…

Answer 14

multipolar

Question 15

Most interneurons are …

Answer 15

multipolar

Question 16

Interneurons are responsible for

Answer 16

transmitting impulses between sensory and motor neurons. Most abundant

Question 17

Neuroglia characteristics

Answer 17

• not electrically excitable
• make up about half of the volume of the nervous system
• can multiply and divide
• 6 types

Question 18

What are the 4 types of neuroglia in the CNS

Answer 18

• astrocytes
• oligodendrocytes
• microglia
• ependymalF

Question 19

Function of astrocytes

Answer 19

• support neurons in the CNS
• maintain the chemical environment (Ca2+ and K+)

Question 20

Function of oligodendrocytes

Answer 20

produce myelin in the CNS

Question 21

Function of microglia

Answer 21

participate in phagocytosis

Question 22

Function of ependymal cells

Answer 22

form and circulate CSF

Question 23

What are the 2 types of neuroglia in the PNS

Answer 23

• Satellite cells
• Scwann cells

Question 24

Function of Satellite cells

Answer 24

• provide structural support
• regulate the exchanges of materials between neuronal cell bodies and interstitial fluid

Question 25

Function of Schwann cells

Answer 25

they form the myelin sheath around axons in the PNS just like oligodendrocytes in the CNS

Question 26

Function of myelin sheath

Answer 26

- insulates and protects electrical signals - fat ( causes the plasma membrane to look thicker on slides) - plasma; lipid bilayer

Question 27

Gray matter vs white matter

Answer 27

- White matter: composed of primarily myelinated axons - Gray matter consists of unmyelinated axons

Question 28

Membrane potential

Answer 28

the difference in charges between the inside and the outside of the cell

Question 29

How to neurons (excitable cells) communicatte with one another

Answer 29

via action potentials or graded potentials

Question 30

Action potentials Vs Graded potentials

Answer 30

allow communication over short and long distances whereas graded potentials allow communication over short distances only

Question 31

What determines production of AP or GP

Answer 31

depends on the existence of a resting membrane potential and the existence of certain ion channels

Question 32

Ion Channels; Leak channels (description + location)

Answer 32

- gated channels that randomly open and close - found in nearly all cels, and dendrites, cell bodies, and axons of all types of neurons

Question 33

Ion Channels; Ligand -gated channels (description + location)

Answer 33

- gated channels that open in response to binding of ligand (chemical) stimulus

Question 34

Ion Channels; Mechanically-gated channels (description + location)

Answer 34

- gated channels that open in response to mechanical stimulus (such as touch, pressure, vibration, or tissue stretching)

Question 35

Ion Channels; Voltage-gated channels (description + location)

Answer 35

- gated channels that open in response to voltage stimulus (change in membrane potential)

Question 36

Resting membrane potential

Answer 36

- the membrane of a non-conducting neuron is positive outside and negative inside.

Question 37

What is resting membrane potential (negative inside and positive outside) determined by:

Answer 37

1. unequal distribution of ions across the plasma membrane and selectively permeability of the neuron's membrane to Na+ and K+ 2. most anions cannot leave the cell (negatively charged have to go through membrane proteins) 3. Na+/K+ pumps

Question 38

Graded potentials

Answer 38

- small deviations in resting membrane potential

Question 39

A graded potential occurs in response to the opening of a ...

Answer 39

mechanically-gated or ligand-gated ion channels