Lecture 06. CNS

Question 1

Central Nervous System

Answer 1

• Information Transfer
• Basic Pattern
• Spinal Cord
• Brain

Question 2

Information Transfer

Answer 2

Information can pass through the CNS via Long Neural Pathways Multsynaptic Pathways

Question 3

Basic Pattern of CNS

Answer 3

Question 4

CNS - Spinal Cord

Answer 4

Question 5

Reflexes

Answer 5

A reflex is a rapid, predictable motor response to a stimulus.

Reflexes may:

• Be inborn or learned (acquired)
• Involved only in peripheral nerves and the spinal cord
• Involve high brain centers as well

Question 6

Reflex Arc

Answer 6

Question 7

Reflex Classification

Answer 7

• Classified Functionally
• Somatic Reflexes
• Autonomic Reflexes

Question 8

Reflexes in Adult Humas

Answer 8

• Accommodation reflex
• Achilles reflex
• Biceps stretch reflex
• Brachioradialis reflex
• Corneal reflex (also known as the blink reflex)
• Crossed extensor reflex
• Gag reflex
• Mammalian diving reflex
• Patellar reflex (knee-jerk reflex)
• Photic sneeze reflex
• Plantar reflex (Babinski reflex)
• Pupillary reflex
• Quadriceps reflex
• Salivation
• Scratch reflex
• Sneeze
• Tendon reflex
• Triceps stretch reflex
• Vestibulo-ocular reflex
• Withdrawal reflex
• Yawn

Question 9

Crossed Extensor Reflex

Answer 9

Question 10

Mammalian Diving Reflex

Answer 10

Submerging the face into water causes the mammalian diving reflex

Includes three factors:

• Bradycardia
• Peripheral vasoconstriction
• Blood shift

When the face is submerged, receptors that are sensitive to water within the nasal cavity and other areas of the face supplied by cranial nerve V (trigeminal) relays the information to the brain and then innervates cranial nerve X (vagus).

Question 11

Photic Sneeze Reflex

Answer 11

A medical condition by which people exposed to bright light sneeze.

• Occurs in 17% to 25% of humans
• The probable cause is a congenital malfunction in nerve signals in the trigeminal nerve nucleus.
• Overstimulation of the optic nerve triggers the trigeminal nerve, and this causes the photic sneeze reflex.

Question 12

Yawn

Answer 12

A reflex of deep inhalation and exhalation associated with being tired, with a need to sleep, or from lack of stimulation. Pandiculation.

• It is claimed to help increase the state of alertness of a person. It could possibly be from lack of oxygen.
• The exact causes of yawning are still unknown.

Question 13

Spinal Cord Trauma: Transection

Answer 13

• Cross sectioning of the spinal cord at any level results in total motor and sensory loss in regions inferior to the cut
• Paraplegia – transection between T1 and L1
• Quadriplegia – transection in the cervical region

Question 14

Poliomyelitis

Answer 14

• Destruction of the anterior horn motor neurons by the poliovirus
• Early symptoms – fever, headache, muscle pain and weakness, and loss of somatic reflexes

Question 15

The Brain

Answer 15

• Composed of wrinkled, pinkish gray tissue
• Surface anatomy includes cerebral hemispheres, cerebellum, and brain stem

Question 16

Adult Neural Canal Regions

Answer 16

Question 17

Ventricles of The Brain

Answer 17

Question 18

Protection of the Brain

Answer 18

• The brain is protected by bone, meninges, and cerebrospinal fluid
• Harmful substances are shielded from the brain by the blood-brain barrier

Question 19

Meninges

Answer 19

• Three connective tissue membranes that lie external to the CNS – dura mater, arachnoid mater, and pia mater
• Functions of the meninges include:
  
  • Cover
  • Protect
  • Contain
  • Form

Question 20

Dura Mater

Answer 20

Question 21

Arachnoid Mater

Answer 21

Question 22

Pia Mater

Answer 22

Question 23

Cerebrospinal Fluid (CSF)

Answer 23

Question 24

Choroid Plexuses

Answer 24

Question 25

Blood-Brain Barrier

Answer 25

* Protective mechanism that helps maintain a stable environment for the brain * Bloodborne substances are separated from neurons by: * Continuous endothelium of capillary walls * Relatively thick basal lamina * Bulbous feet of astrocytes

Question 26

Blood-Brain Barrier: Functions

Answer 26

* Reduce the immune systems access to the brain * Comprised of the cells that make up the smallest blood vessels of the brain * Anatomical structures * Physiological transport systems * Accounts for some drug actions * Morphine vs. heroin * Many substances are not lipid soluble * Glucose and other important brain substrates

Question 27

Brain

Answer 27

* Brainstem * Midbrain * Pons * Medulla Oblongata * Cerebellum * Forebrain * Diencephalon * Cerebrum * Limbic System

Question 28

Midbrain

Answer 28

* Located between the diencephalon and the pons * Midbrain structures include: * Corpora quadrigemina * Superior Colliculi * Inferior Colliculi * Sustantia nigra * Cerebral Aqueduct

Question 29

Midbrain Nuclei

Answer 29

Question 30

Pons

Answer 30

Question 31

Medulla Oblongata

Answer 31

Question 32

Cerebellum

Answer 32

Question 33

Forebrain

Answer 33

* Two Regions * Cerebrum * Diencephalon

Question 34

Cerebrum

Answer 34

Question 35

Functional Areas: Left Cerebral Cortex

Answer 35

Question 36

Primary Motor Cortex

Answer 36

Question 37

Sensorymotor Cortex

Answer 37

* Premotor cortex * Supplementary motor cortex * Parietal-lobe association cortex

Question 38

Somatosensory Cortex

Answer 38

Question 39

Diencephalon

Answer 39

Question 40

Limbic System

Answer 40

Question 41

Cerebrovascular Accidents

Answer 41

Question 42

Brain Atrophy in Advanced Alzheimer's Disease

Answer 42

Question 43

Huntingtons Disease

Answer 43

* Genetic disorder * HD gene located on chromosome 4 * Extra CAG repeat on the end of the gene * Caused by degeneration of neuronal cells * Frontal lobes * Basal ganglia * Caudate nucleus * Symptoms * Jerky uncoordinated movements which become progressively worse * Excecutive function, abstract thinking, speech and perceptual and spatial function are all affected

Question 44

Blood Supply

Answer 44