Nervous System

Question 1

Functions of nervous system:

Answer 1

1. Sensory input
2. Integration
3. Control of muscles and glands
4. Mental activity
5. Homeostasis

Question 2

Main Divisions of the Nervous System:

Answer 2

1. Central Nervous System (CNS): brain and spinal cord
2. Peripheral Nervous System (PNS): all neurons outside CNS

Question 3

Neuron Characteristics:

Answer 3

• Nerve cells
• Require oxygen and glucose
• Receive input, process input, and produce a response

Question 4

Neuron Structures:

Answer 4

• Dendrite - receives stimulus from other neurons or sensory receptors
• Cell body - processes stimulus, contains a nucleus
• Axon - transmits stimulus to a gland, muscle, organ, or other neuron

Question 5

Myelin Sheath

Answer 5

fatty, protective wrapping around axons

Question 6

gaps in myelin sheath where action potentials develop

Answer 6

Nodes of Ranvier

Question 7

jumping of action potentials

Answer 7

Saltatory conduction

Question 8

disease of myelin sheath that causes loss of muscle function

Answer 8

Multiple sclerosis

Question 9

Types of Neurons:

Answer 9

• Multipolar neuron - many dendrites and a single axon
• Bipolar neuron - one dendrite and one axon
• Pseudo-unipolar neuron - one axon and no dendrites

Question 10

Neuroglia Characteristics:

Answer 10

• Supporting cells for neurons
• More numerous than neurons
• Can divide to produce more cells

5 types:
- Astrocytes
- Ependymal Cells
- Microglia
- Oligodendrocytes
- Schwann cells

Question 11

• star-shaped
• most abundant
• form blood-brain barrier

Answer 11

Astrocytes

Question 12

produce and circulate cerebrospinal fluid (CSF)

Answer 12

Ependymal Cells

Question 13

help remove bacteria and cell debris from CNS

Answer 13

Microglia

Question 14

produce myelin sheath in CNS

Answer 14

Oligodendrocytes

Question 15

produce myelin sheath in PNS

Answer 15

Schwann cells

Question 16

Organization of Nervous Tissue:

Answer 16

• Gray matter: - collection of dendrites and cell bodies
• White matter: - collection of axons and their myelin sheath

Question 17

Produce myelin sheath:

Answer 17

CNS: Oligodendrocytes
PNS: Schwann cells

Question 18

Collection of axons:

Answer 18

CNS: Nerve tracts
PNS: Nerves

Question 19

Collection of cell bodies:

Answer 19

CNS: Nuclei
PNS: Ganglion

Question 20

Resting Membrane Potential:

Answer 20

• Outside of cell is more + (Na+)
• Inside of cell is more – (K+)
• Leak ion channels:
  
  • always open
  • K+ channels
• Gated ion channels:
  
  • closed until opened by specific signal
  • Na+ channels

Question 21

• “Electricity” that cause depolarization and repolarization
• Change resting membrane potential by activating gated ion channels

Answer 21

Action Potentials

Question 22

If enough Na+ enters then ________ is reached and more Na+ channels open

Answer 22

threshold

Question 23

Action potentials continue until Na+ channels close, K+ channels open, and ________ occurs

Answer 23

repolarization

Question 24

where an axon attaches to a muscle, gland, organ, or other neuron

Answer 24

Synapse

Question 25

involuntary response to a stimulus

Answer 25

Reflexes

Question 26

path reflex travels

Answer 26

Reflex arc

Question 27

Components of Reflex Arc:

Answer 27

**1. Sensory receptors:** - pick up the stimulus - in skin **2. Sensory (afferent) neurons:** send stimulus to interneurons in the spinal cord **3. Interneurons (Association) neuron:** - located in the CNS and connected to motor neurons - process stimulus **4. Efferent (motor) neurons:** send a response to the effector **5. Effector:** muscle, gland, or organ

Question 28

two or more neurons synapse the same neuron

Answer 28

Converging

Question 29

axon from one neuron divides and synapses with more than one neuron

Answer 29

Diverging

Question 30

Consists of brain and spinal cord

Answer 30

Central Nervous System

Question 31

It includes nerves outside the brain and spinal cord

Answer 31

Peripheral Nervous System

Question 32

Extends from foramen magnum to 2nd lumbar vertebra

Answer 32

Spinal Cord

Question 33

Gray and White Matter in Spinal Cord:

Answer 33

**Gray Matter:** center of the spinal cord looks like the letter H or a butterfly **White Matter:** outside of the spinal cord contains myelinated fibers

Question 34

White Matter in Spinal Cord

Answer 34

* Contains 3 columns dorsal, ventral, and lateral columns * **Ascending tracts:** axons that conduct action potentials **toward** the brain * **Descending tracts:** axons that conduct action potentials **away** from the brain

Question 35

Gray Matter in Spinal Cord:

Answer 35

**Posterior horns:** contain axons that synapse with interneurons **Anterior horns:** contain somatic neurons **Lateral horns:** contain autonomic neurons **Central canal:** fluid-filled space in the center of the cord

Question 36

Arise along spinal cord from union of dorsal roots and ventral roots

Answer 36

Spinal Nerves

Question 37

Originates from spinal nerves C1-4, it **innervates** muscles attached to the hyoid bone and neck

Answer 37

Cervical Plexus

Question 38

Originates from spinal nerves C5-T1, it supplies nerves to the **upper limb, shoulder, hand**

Answer 38

Brachial Plexus

Question 39

Originates from spinal nerves L1 to S4, it supplies nerves in the **lower limbs**

Answer 39

Lumbosacral Plexus

Question 40

Fluid that bathes the brain and spinal cord

Answer 40

Cerebrospinal Fluid

Question 41

Brainstem components:

Answer 41

* Medulla oblongata * Pons * Midbrain

Question 42

component of the brainstem that regulates heart rate, blood vessel diameter, breathing, swallowing, vomiting, hiccupping, coughing, sneezing, balance

Answer 42

Medulla oblongata

Question 43

component of the brainstem that regulates breathing, chewing, salivation, swallowing

Answer 43

Pons

Question 44

component of the brainstem that coordinated the eye movement, pupil diameter, turning head toward noise

Answer 44

Midbrain

Question 45

regulates cyclical motor function, respiration, walking, chewing, arousing, and maintaining consciousness regulates the sleep-wake cycle

Answer 45

Reticular Formation

Question 46

Diencephalon:

Answer 46

* Located between the brainstem and cerebrum **Components:** * **Thalamus** - influences moods and detects pain * **Epithalamus** - an emotional and visceral response to odors * **Hypothalamus** - controls homeostasis, body temp, thirst, hunger, fear, rage, sexual emotions