CH 3: The Brain, NS & Neural Communication

Question 1

List the major divisions of the nervous system (8)

Answer 1

1. Central Nervous System
   - Brain
   - Spinal Cord
2. Peripheral Nervous System
   - Somatic NS
   - Autonomic NS
   - -> Sympathetic NS
   - -> Parasympathetic NS

Question 2

Describe the CNS

Answer 2

• Central Nervous System

- NS in skull & spine = brain & spinal cord

Question 3

Describe the PNS

Answer 3

• Peripheral Nervous System
• NS outside of skull & spine
• Composed of the Somatic NS & Autonomic NS

Question 4

Describe the Somatic NS

Answer 4

• Part of the PNS that interacts w/ EXTERNAL environ

- Composed of afferent nerves & efferent nerves

Question 5

Describe AFFERENT NERVES in Somatic NS

Answer 5

• Carries SENSORY signals from skin, skeletal muscles, joints, eyes, ears, etc. to CNS

Question 6

Describe EFFERENT NERVES in Somatic NS

Answer 6

• Carries MOTOR signals from CNS to skeletal muscles

Question 7

Describe the Autonomic NS

Answer 7

• Part of PNS that regulates body’s INTERNAL environ

- Composed of afferent nerves & efferent nerves

Question 8

Describe AFFERENT NERVES in Autonomic NS

Answer 8

• Carries SENSORY signals from internal organs to CNS

Question 9

Describe EFFERENT NERVES in Autonomic NS

Answer 9

• Carries MOTOR signals from CNS to internal organs

Question 10

Name the 2 types of nerves in Autonomic NS

Answer 10

• Sympathetic Nerves

- Parasympathetic Nerves

Question 11

Describe Sympathetic Nerves (3)

Answer 11

• Autonomic motor nerves that project from CNS in the lumbar (small of back)
• ***Stimulate, organize & mobilize E resources in threatening situations
• Sympathetic changes are indicative of psychological AROUSAL

Question 12

Describe Parasympathetic Nerves (3)

Answer 12

• Autonomic motor nerves that project from brain & sarcal (lower back) regions of spinal cord
• ***Acts to conserve E
• Parasympathetic changes are indicative of psychological RELAXATION

Question 13

Define MENINGES.

Answer 13

• 3 protective membranes that cover the brain & spinal cord

Question 14

List the 3 meninges & explain their functional role.

Answer 14

(1) Dura Mater = tough outer meninx
(2) Arachnoid Membrane = spiderweb-like meninx located b/w dura mater & pia mater
(3) Pia Mater = delicate, innermost meninx

Question 15

Describe function of CEREBROSPINAL FLUID (CSF).

Answer 15

• Supports/cushions the brain

Question 16

Where is CSF produced?

Answer 16

• Produced by CHOROID PLEXUSES = networks of capillaries that protrude into ventricles from the pia matter

Question 17

Where does CSF flow? (3).

Answer 17

(1) Subarachnoid Space = space beneath arachnoid membrane - contains many large bv’s & CSF
(2) Central Canal = small central canal that runs length of spinal cord
(3) Cerebral Ventricles = 4 large internal chambers of brain

Question 18

Define BLOOD-BRAIN BARRIER & describe its function

Answer 18

• Mechanism that impedes the passage of toxic substances from blood into brain
• Formed due to tightly packed bv walls of brain cells

Question 19

List the 4 types of GLIAL CELLS

Answer 19

1. Oligodendrocytes
2. Schwann Cells
3. Microglia
4. Astrocytes

Question 20

Define 1. OLIGODENDROCYTES

Answer 20

• Glial cells that myelinated neurons of the CNS

- -> increases speed of transduction

Question 21

Define 2. SCHWANN CELLS

Answer 21

• Glial cells that compose the myelin sheaths of PNS axons & promote the regeneration of PNS axons

Question 22

Define 3. MICROGLIA

Answer 22

• Glial cells that respond to injury/disease engulfing cellular debris & triggering inflammatory responses
• Plays role in regulation of cell death

Question 23

Define 4. Astrocytes

Answer 23

• Large, star-shaped glial cells that play multiple roles in the CNS
• ie) exchange chemical signals w/ neurons & other astrocytes

Question 24

List 5 neuroanatomical research techniques.

Answer 24

1. Golgi stain
2. Nissl stain
3. Electron microscopy
4. Anterograde tracing methods
5. Retrograde tracing methods

Question 25

Describe 1. GOLGI STAIN

Answer 25

- Neural stain that completely darkens a few of the neurons in each slice of tissue - > reveals their silhouettes - > see individual neurons

Question 26

Describe 2. NISSL STAIN

Answer 26

- Neural stain that has an affinity for structures in neuron cell bodies

Question 27

Describe 3. ELECTRON MICROSCOPY

Answer 27

- Microscopy technique used to study fine details of cellular structure

Question 28

Describe 4. ANTEROGRADE TRACING METHODS

Answer 28

- Used when want to trace paths of axons projecting AWAY from cell bodies

Question 29

Describe 5. RETROGRADE TRACING METHODS

Answer 29

- Used when want to trace paths of axons projecting INTO a particular area

Question 30

Define ANTERIOR

Answer 30

- Towards the nose end

Question 31

Define POSTERIOR

Answer 31

- Towards the tail end

Question 32

Define DORSAL

Answer 32

- Top of human head & back of human body

Question 33

Define VENTRAL

Answer 33

- Bottom of human head & front of human body

Question 34

Define MEDIAL

Answer 34

- Towards midline of body

Question 35

Define LATERAL

Answer 35

- Away from midline toward body's lateral surfaces

Question 36

List the 5 major components of the spinal cord.

Answer 36

1. Gray Matter 2. White Matter 3. Dorsal Horns 4. Ventral Horns 5. Dorsal Root Ganglia

Question 37

Describe GRAY MATTER

Answer 37

- Composed of cell bodies & un-myelinated interneurons

Question 38

Describe WHITE MATTER

Answer 38

- Composed of myelinated axons

Question 39

Describe DORSAL HORNS

Answer 39

- 2 dorsal arms of the spinal grey matter

Question 40

Describe VENTRAL HORNS

Answer 40

- 2 ventral arms of the spinal grey matter

Question 41

Describe DORSAL ROOT GANGLIA

Answer 41

- Structures just outside the spinal cord that are composed of cell bodies of dorsal root axons

Question 42

List the 5 major divisions of the brain.

Answer 42

FOREBRAIN: 1. Telencephalon (aka cerebral hemispheres) 2. Diencephalon MIDBRAIN: 3. Mesencephalon (aka midbrain) HINDBRAIN: 4. Metencephalon 5. Myelencephalon (aka medulla) - 2-5 = brain stem = stem on which cerebral hemispheres sit