Nervous tissue

Question 1

What are the two main divisions of the nervous system?

Answer 1

• Central Nervous system (brain and spinal cord)
• Peripheral Nervous system (Nerves, ganglia, and sensory receptors)

Question 2

How do nerves respond to external stimuli?

Answer 2

By generating an action potential and transmitting it to the CNS for analysis and processing.

Question 3

What is the functional unit of the nervous system?

Answer 3

A NEURON

Question 4

Name the parts of a neuron

Answer 4

Cell body

Dendrites

Axon hillock

Axon

Axon terminal

Question 5

What is the cell body of a neuron?

Answer 5

Contains a nucleus and most of the cell’s organelles.

Site of neurotransmitter production

Contains a lot of microfilaments that aid in moving the neurotransmitters from the cell body to the axon terminal

Question 6

What are dendrites?

Answer 6

These are extensions of the cell body that specialize in receiving stimuli from other neurons via synapses.

Question 7

What is an axon?

Answer 7

A single long process ending at synapses that can generate and conduct action potentials

They also receive information from other cells that mainly modify the transmission to those neurons.

Question 8

How are neurons classified?

Answer 8

Structure and function

Question 9

Multipolar neuron

Answer 9

One axon and two or more dendrites

Typical neuron

Question 10

Bipolar neurons

Answer 10

One dendrite and one axon

Question 11

Unipolar or pseudounipolar neuron

Answer 11

A single process that bifurcates close to the cell body with the longer branch extending to the peripheral ending and the other toward the CNS

Question 12

Anaxonic neurons

Answer 12

Many dendrites but no true axon.

DO NOT produce action potentials, but regulates electrical changes of adjacent neurons

Question 13

What types of classification do most neurons have?

Answer 13

Multipolar

Question 14

Where are bipolar neurons found?

Answer 14

Retina → senses sight

Olfactory mucosa → senses smell

Inner ear (Cochlear and vestibular ganglia) → balance

Question 15

Where are pseudounipolar neurons found?

Answer 15

Spinal ganglia and in most cranial ganglia.

Question 16

How are nervous components subdivided functionally?

Answer 16

Sensory neurons → afferent as they receive stimuli from the receptors throughout the body

Motor neurons → efferent because they send impulses to effector organs (glands, muscles)

Question 17

What are the types of motor nerves?

Answer 17

Somatic → under voluntary control and innervates skeletal muscle and skin

Autonomic→ involuntary activates glands, cardiac muscle and most smooth muscle

Question 18

What are interneurons

Answer 18

Forms circuits between neurons

Generally multipolar or anaxonic

Question 19

Microglia

Answer 19

• Mobile phagocytic cells (macrophages) that are derived from monocytes
• Smallest glial cellls
• Stains dark with elongates nucleus and little cytoplasm