Chapter Four - The Nervous System

Question 1

What are the 2 Main Divisions of the NS?

Answer 1

• CNS: Brain, & Spinal Cord.
• PNS: Outside the skull, most nerves project from spinal cord except the 12 pairs of nerves called cranial nerves which project from the brain.

Question 2

Nerve vs. Tract?

Answer 2

• Nerve: collection of axons outside the CNS.
• Tract: collection of axons inside the CNS.

Question 3

Afferent vs. Efferent?

Answer 3

• Afferent = towards area of interest.
• Efferent = away from area of interest.

Question 4

What neurons are often found in a cluster?

Answer 4

• Ganglion = a cluster or neuron cell bodies outside the CNS.
• Nucleus = a cluster of neuron cell bodies insdie the CNS.

Question 5

What are the two subdivisions of the PNS?

Answer 5

1. Somatic NS.
2. Autonomic NS.

Question 6

Somatic Nervous System?

Answer 6

• Interacts with the body’s external environment [body surface and muscles].

Question 7

ANS?

Answer 7

• Interacts with the body’s internal environment [internal organs].
• Efferent nerves are divided into two systmes based on where their cell bodies are located within the spinal cord.

Question 8

ANS 2 Subdivisons?

Answer 8

1. Sympathetic.
2. Parasympathetic.

Question 9

Sympathetic NS?

Answer 9

• motor nerves project from neurons in the lumbar and thoracic spine regions.
• controls involuntary movement of various internal organs.
• prepares body for fight or flight.
• arousal.
• increases heart rate, facilitates breathing, dilates pupil, inhibits digestion.

Question 10

Parasympathetic NS?

Answer 10

• motor nerves project from neurons in thebranial and sacral regions.
• decreases breathing, heart rate, and constricts pupil, and stimulates digestion.

Question 11

Spine & Vertebrate Sections?

Answer 11

33 vertebrates.
- Cervical spine = 7 in the neck.
- Thoracic spine = 12 in the upper back.
- Lumbar spine = 5 in lower back.
- Sacrum spine = 5 fused vertebrates.
- Coccyx spine = 4 fused vertebrates.

Question 12

What structures protect the CNS?

Answer 12

• Physical protection = bones, membranes, and CSF.
• Chemical protection = BBB.

Question 13

What are the 3 Meninges?

Answer 13

1. Dura Mater = closest to skull.
2. Arachnoid Membrane = arachnoid.
3. Pia Mater = closest.

Question 14

How many cranial nerves project from the brain?

Answer 14

• 12 nerves.

Question 15

Ventricular System:

Answer 15

• 4 ventricles in the brain: 2 lateral, one third, and one foruth ventricle.

Question 16

Two main functions of CSF?

Answer 16

1. Acts as a shock absorber.
2. Provides an exchange medium between blood and brain.

• CSF is produced by a network of capillaries of blood vessels, called chorid plexus, an organ protruding into the ventricles.

Question 17

Blood Brain Barrier:

Answer 17

• Tightly packed cells of blood vessel walls prevent the entry of many molecules.
• Functions: protects brain from foreign substances, hormones, transmitters, and maintains a constant environment for the brain.

Question 18

What are the two types of cells in the NS?

Answer 18

• Neurons.
• Glia.

Question 19

Glia to neuron ratio?

Answer 19

• Outnumber neurons 10:1.

Question 20

Four main classes of Glial cells?

Answer 20

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

Question 21

Forebrain?

[ what are the long terms]

Answer 21

• Telencephalon.
• Diencephalon.

Question 22

Midbrain?

[ long name]

Answer 22

Mesencephalon.

Question 23

Hindbrain?

[long names]

Answer 23

• Metencephalon.
• Myelencephalon.

Question 24

How many pairs of spinal nerves are there?

Answer 24

• 31 pairs of spinal nerves.

Question 25

Gray vs. White Matter?

Answer 25

- Gray: inner component, primarily cell bodies. - White: outer area, mainly myelinated axons.

Question 26

Hindbrain Structures?

Answer 26

- Medulla. - Pons. - Cerebellum. - Reticular Formation.

Question 27

Medulla?

Answer 27

- Composed largely of axon tracts.

Question 28

Pons?

Answer 28

- Some nuclei involved in sleep and arousal, others invovles in movement and muscle tone.

Question 29

Cerebellum?

Answer 29

- Consists of cerebellar cortex and subcortical cerebellar nuclei. - Involves in motor control.

Question 30

Midbrain Structures?

Answer 30

- Tectum. - Tegmentum.

Question 31

Tectum?

Answer 31

- Doral part. - consists of 2 pairs of bumps, (1) superior colliculis, which recieves visual info, and (2) inferior colliculus, which recieves auditory info.

Question 32

Tegmentum?

Answer 32

- Ventral part. - consists of reticular formation, periaqueductal gray, substantia nigra, and the red nucleus. - periaqueductal gray = gray matter around the acquduct, mediating pain sensation. - substantia nigra and red nucleus = involved in motor function.

Question 33

Forebrain Structures?

Answer 33

- Thalamus. - Hypothalamus. - Basal ganglia. - Limbic system. - Cerebral cortex.

Question 34

Thalamus?

Answer 34

- 2 lobed structure sitting on top of the brainstem. - The main relay station of the brain. - Made up of many nuclei, each of which recieves different sensory info. - Laterl geniculate nuclei = visual. - Medial ^ = auditory. - Ventral posterior nuclei = somatosensory.

Question 35

Hypothalamus?

Answer 35

- Locaed ventral of the thalamus.

Question 36

Basal Ganglia?

Answer 36

- consits of amygdala, striatum, & globus pallidus. - necessary for sensory-driven and goal directed voluntary movement.

Question 37

Limbic System?

Answer 37

- A group of structures surrounding the thalamus like a ring shape. - Hippocampus, amygdala, fornix, cingulate cortex, septum, and mammillary bodies. - Involved in the four Fs: fighting, feeding, fleeing , sexual behaviours.

Question 38

Cerebral Cortex?

Answer 38

- Right and left hemispheres. - Hemispheres conncected by corpus callosum. - Four lobes: parietal, frontal, occipital, and temporal.

Question 39

4 Lobes Responsibilities?

Answer 39

- Frontal = higher cognition, motor function. - Parietal = somatosensation. - Occipital = visual perception. - Temporal = hearing, language, & memory.